| blob | 507675b4aae685a0eaf47d5451e2cddf00c94037 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 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". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 alias template (needed by instantiate_decl). */
232 static void
234 {
242 else
246 {
247 saved_access_scope = tree_cons
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 static void
258 {
260 {
263 }
267 else
269 }
271 /* Do any processing required when DECL (a member template
272 declaration) is finished. Returns the TEMPLATE_DECL corresponding
273 to DECL, unless it is a specialization, in which case the DECL
274 itself is returned. */
276 tree
278 {
285 {
286 tree type;
294 {
298 }
300 }
304 {
306 {
309 }
310 else
312 }
313 else
317 }
319 /* Create a template info node. */
321 tree
323 {
328 }
330 /* Return the template info node corresponding to T, whatever T is. */
332 tree
334 {
356 }
358 /* Returns the template nesting level of the indicated class TYPE.
360 For example, in:
361 template <class T>
362 struct A
363 {
364 template <class U>
365 struct B {};
366 };
368 A<T>::B<U> has depth two, while A<T> has depth one.
369 Both A<T>::B<int> and A<int>::B<U> have depth one, if
370 they are instantiations, not specializations.
372 This function is guaranteed to return 0 if passed NULL_TREE so
373 that, for example, `template_class_depth (current_class_type)' is
374 always safe. */
376 int
378 {
382 {
393 else
395 }
398 }
400 /* Subroutine of maybe_begin_member_template_processing.
401 Returns true if processing DECL needs us to push template parms. */
403 static bool
405 {
411 }
413 /* Subroutine of maybe_begin_member_template_processing.
414 Push the template parms in PARMS, starting from LEVELS steps into the
415 chain, and ending at the beginning, since template parms are listed
416 innermost first. */
418 static void
420 {
428 current_template_parms
434 NULL);
436 {
445 {
452 /* Push the CONST_DECL. */
458 }
459 }
460 }
462 /* Restore the template parameter context for a member template, a
463 friend template defined in a class definition, or a non-template
464 member of template class. */
466 void
468 {
469 tree parms;
474 {
477 /* Disregard full specializations (c++/60999). */
480 }
483 {
488 {
491 }
494 }
496 /* Remember how many levels of template parameters we pushed so that
497 we can pop them later. */
499 }
501 /* Undo the effects of maybe_begin_member_template_processing. */
503 void
505 {
514 {
518 }
519 }
521 /* Return a new template argument vector which contains all of ARGS,
522 but has as its innermost set of arguments the EXTRA_ARGS. */
524 static tree
526 {
527 tree new_args;
545 }
547 /* Like add_to_template_args, but only the outermost ARGS are added to
548 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
549 (EXTRA_ARGS) levels are added. This function is used to combine
550 the template arguments from a partial instantiation with the
551 template arguments used to attain the full instantiation from the
552 partial instantiation. */
554 static tree
556 {
557 tree new_args;
559 /* If there are more levels of EXTRA_ARGS than there are ARGS,
560 something very fishy is going on. */
563 /* If *all* the new arguments will be the EXTRA_ARGS, just return
564 them. */
568 /* For the moment, we make ARGS look like it contains fewer levels. */
573 /* Now, we restore ARGS to its full dimensions. */
577 }
579 /* Return the N levels of innermost template arguments from the ARGS. */
581 tree
583 {
584 tree new_args;
590 /* If N is 1, just return the innermost set of template arguments. */
594 /* If we're not removing anything, just return the arguments we were
595 given. */
601 /* Make a new set of arguments, not containing the outer arguments. */
608 }
610 /* The inverse of get_innermost_template_args: Return all but the innermost
611 EXTRA_LEVELS levels of template arguments from the ARGS. */
613 static tree
615 {
616 tree new_args;
622 /* If N is 1, just return the outermost set of template arguments. */
626 /* If we're not removing anything, just return the arguments we were
627 given. */
632 /* Make a new set of arguments, not containing the inner arguments. */
639 }
641 /* We've got a template header coming up; push to a new level for storing
642 the parms. */
644 void
646 {
647 /* We use a non-tag-transparent scope here, which causes pushtag to
648 put tags in this scope, rather than in the enclosing class or
649 namespace scope. This is the right thing, since we want
650 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
651 global template class, push_template_decl handles putting the
652 TEMPLATE_DECL into top-level scope. For a nested template class,
653 e.g.:
655 template <class T> struct S1 {
656 template <class T> struct S2 {};
657 };
659 pushtag contains special code to insert the TEMPLATE_DECL for S2
660 at the right scope. */
666 /* Add a dummy parameter level while we process the parameter list. */
667 current_template_parms
670 current_template_parms);
671 }
673 /* This routine is called when a specialization is declared. If it is
674 invalid to declare a specialization here, an error is reported and
675 false is returned, otherwise this routine will return true. */
677 static bool
679 {
682 /* [temp.expl.spec]
684 An explicit specialization shall be declared in the namespace of
685 which the template is a member, or, for member templates, in the
686 namespace of which the enclosing class or enclosing class
687 template is a member. An explicit specialization of a member
688 function, member class or static data member of a class template
689 shall be declared in the namespace of which the class template
690 is a member. */
692 {
695 }
697 /* [temp.expl.spec]
699 In an explicit specialization declaration for a member of a class
700 template or a member template that appears in namespace scope,
701 the member template and some of its enclosing class templates may
702 remain unspecialized, except that the declaration shall not
703 explicitly specialize a class member template if its enclosing
704 class templates are not explicitly specialized as well. */
706 {
709 }
712 }
714 /* We've just seen template <>. */
716 bool
718 {
722 }
724 /* Called at then end of processing a declaration preceded by
725 template<>. */
727 void
729 {
732 }
734 /* Any template <>'s that we have seen thus far are not referring to a
735 function specialization. */
737 void
739 {
742 }
744 /* We've just seen a template header. If SPECIALIZATION is nonzero,
745 it was of the form template <>. */
747 static void
749 {
751 template_header_count++;
752 }
754 /* We're beginning an explicit instantiation. */
756 void
758 {
761 }
764 void
766 {
769 }
771 /* An explicit specialization or partial specialization of TMPL is being
772 declared. Check that the namespace in which the specialization is
773 occurring is permissible. Returns false iff it is invalid to
774 specialize TMPL in the current namespace. */
776 static bool
778 {
781 /* [tmpl.expl.spec]
783 An explicit specialization shall be declared in a namespace enclosing the
784 specialized template. An explicit specialization whose declarator-id is
785 not qualified shall be declared in the nearest enclosing namespace of the
786 template, or, if the namespace is inline (7.3.1), any namespace from its
787 enclosing namespace set. */
790 {
793 }
796 /* Same or enclosing namespace. */
798 else
799 {
805 }
806 }
808 /* SPEC is an explicit instantiation. Check that it is valid to
809 perform this explicit instantiation in the current namespace. */
811 static void
813 {
814 tree ns;
816 /* DR 275: An explicit instantiation shall appear in an enclosing
817 namespace of its template. */
823 }
825 // Returns the type of a template specialization only if that
826 // specialization needs to be defined. Otherwise (e.g., if the type has
827 // already been defined), the function returns NULL_TREE.
828 static tree
830 {
831 // An implicit instantiation of an incomplete type implies
832 // the definition of a new class template.
833 //
834 // template<typename T>
835 // struct S;
836 //
837 // template<typename T>
838 // struct S<T*>;
839 //
840 // Here, S<T*> is an implicit instantiation of S whose type
841 // is incomplete.
845 // It can also be the case that TYPE is a completed specialization.
846 // Continuing the previous example, suppose we also declare:
847 //
848 // template<typename T>
849 // requires Integral<T>
850 // struct S<T*>;
851 //
852 // Here, S<T*> refers to the specialization S<T*> defined
853 // above. However, we need to differentiate definitions because
854 // we intend to define a new partial specialization. In this case,
855 // we rely on the fact that the constraints are different for
856 // this declaration than that above.
857 //
858 // Note that we also get here for injected class names and
859 // late-parsed template definitions. We must ensure that we
860 // do not create new type declarations for those cases.
862 {
866 // If there are no template parameters, this cannot be a new
867 // partial template specializtion?
871 // The injected-class-name is not a new partial specialization.
875 // If the constraints are not the same as those of the primary
876 // then, we can probably create a new specialization.
880 {
884 }
886 // Also, if there's a pre-existing specialization with matching
887 // constraints, then this also isn't new.
890 {
898 }
900 // Create a new type node (and corresponding type decl)
901 // for the newly declared specialization.
906 /* We only need a separate type node for storing the definition of this
907 partial specialization; uses of S<T*> are unconstrained, so all are
908 equivalent. So keep TYPE_CANONICAL the same. */
911 // Build the corresponding type decl.
917 }
920 }
922 /* The TYPE is being declared. If it is a template type, that means it
923 is a partial specialization. Do appropriate error-checking. */
925 tree
927 {
928 tree context;
933 /* A lambda that appears in specialization context is not itself a
934 specialization. */
939 {
943 }
948 {
954 else
957 }
959 {
960 /* This is for ordinary explicit specialization and partial
961 specialization of a template class such as:
963 template <> class C<int>;
965 or:
967 template <class T> class C<T*>;
969 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
972 {
979 {
984 }
985 }
991 /* Trying to define a specialization either without a template<> header
992 or in an inappropriate place. We've already given an error, so just
993 bail now so we don't actually define the specialization. */
995 }
1001 {
1002 /* This is for an explicit specialization of member class
1003 template according to [temp.expl.spec/18]:
1005 template <> template <class U> class C<int>::D;
1007 The context `C<int>' must be an implicit instantiation.
1008 Otherwise this is just a member class template declared
1009 earlier like:
1011 template <> class C<int> { template <class U> class D; };
1012 template <> template <class U> class C<int>::D;
1014 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1015 while in the second case, `C<int>::D' is a primary template
1016 and `C<T>::D' may not exist. */
1020 {
1021 tree t;
1026 {
1031 }
1033 /* Check for invalid specialization after instantiation:
1035 template <> template <> class C<int>::D<int>;
1036 template <> template <class U> class C<int>::D; */
1040 {
1044 {
1045 /* We already have a full specialization of this partial
1046 instantiation, or a full specialization has been
1047 looked up but not instantiated. Reassign it to the
1048 new member specialization template. */
1049 spec_entry elt;
1061 spec_entry **slot
1066 }
1067 else
1068 /* But if we've had an implicit instantiation, that's a
1069 problem ([temp.expl.spec]/6). */
1072 }
1074 /* Mark TYPE as a specialization. And as a result, we only
1075 have one level of template argument for the innermost
1076 class template. */
1081 }
1082 }
1084 {
1085 /* Someday C++0x may allow for enum template specialization. */
1090 else
1091 {
1094 }
1095 }
1098 }
1100 /* Returns nonzero if we can optimize the retrieval of specializations
1101 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1102 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1106 {
1109 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1110 parameter. */
1112 /* The optimized lookup depends on the fact that the
1113 template arguments for the member function template apply
1114 purely to the containing class, which is not true if the
1115 containing class is an explicit or partial
1116 specialization. */
1120 /* It is possible to have a template that is not a member
1121 template and is not a member of a template class:
1123 template <typename T>
1124 struct S { friend A::f(); };
1126 Here, the friend function is a template, but the context does
1127 not have template information. The optimized lookup relies
1128 on having ARGS be the template arguments for both the class
1129 and the function template. */
1131 }
1133 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1134 gone through coerce_template_parms by now. */
1136 static void
1138 {
1141 {
1144 {
1151 /* Allow typedefs on the type of a non-type argument, since a
1153 else
1155 }
1156 }
1158 }
1160 /* Retrieve the specialization (in the sense of [temp.spec] - a
1161 specialization is either an instantiation or an explicit
1162 specialization) of TMPL for the given template ARGS. If there is
1163 no such specialization, return NULL_TREE. The ARGS are a vector of
1164 arguments, or a vector of vectors of arguments, in the case of
1165 templates with more than one level of parameters.
1167 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1168 then we search for a partial specialization matching ARGS. This
1169 parameter is ignored if TMPL is not a class template.
1171 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1172 result is a NONTYPE_ARGUMENT_PACK. */
1174 static tree
1176 {
1186 /* There should be as many levels of arguments as there are
1187 levels of parameters. */
1196 /* Lambda functions in templates aren't instantiated normally, but through
1197 tsubst_lambda_expr. */
1202 {
1203 /* The template arguments actually apply to the containing
1204 class. Find the class specialization with those
1205 arguments. */
1207 tree class_specialization
1212 /* Find the instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. ATTRLIST is the list of
1477 attributes that the specialization is declared with or NULL when
1478 it isn't. Returns SPEC, or an equivalent prior declaration, if
1479 available.
1481 We also store instantiations of field packs in the hash table, even
1482 though they are not themselves templates, to make lookup easier. */
1484 static tree
1486 hashval_t hash)
1487 {
1488 tree fn;
1490 spec_entry elt;
1498 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1499 register it; we want the corresponding TEMPLATE_DECL instead.
1500 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1501 the more obvious `uses_template_parms (spec)' to avoid problems
1502 with default function arguments. In particular, given
1503 something like this:
1505 template <class T> void f(T t1, T t = T())
1507 the default argument expression is not substituted for in an
1508 instantiation unless and until it is actually needed. */
1512 /* We don't put these specializations in the hash table, but we might
1513 want to give an error about a mismatch. */
1515 else
1516 {
1524 slot =
1528 else
1530 }
1532 /* We can sometimes try to re-register a specialization that we've
1533 already got. In particular, regenerate_decl_from_template calls
1534 duplicate_decls which will update the specialization list. But,
1535 we'll still get called again here anyhow. It's more convenient
1536 to simply allow this than to try to prevent it. */
1540 {
1542 {
1545 {
1547 fn);
1549 }
1550 else
1551 {
1552 tree clone;
1553 /* This situation should occur only if the first
1554 specialization is an implicit instantiation, the
1555 second is an explicit specialization, and the
1556 implicit instantiation has not yet been used. That
1557 situation can occur if we have implicitly
1558 instantiated a member function and then specialized
1559 it later.
1561 We can also wind up here if a friend declaration that
1562 looked like an instantiation turns out to be a
1563 specialization:
1565 template <class T> void foo(T);
1566 class S { friend void foo<>(int) };
1567 template <> void foo(int);
1569 We transform the existing DECL in place so that any
1570 pointers to it become pointers to the updated
1571 declaration.
1573 If there was a definition for the template, but not
1574 for the specialization, we want this to look as if
1575 there were no definition, and vice versa. */
1578 /* The call to duplicate_decls will have applied
1579 [temp.expl.spec]:
1581 An explicit specialization of a function template
1582 is inline only if it is explicitly declared to be,
1583 and independently of whether its function template
1584 is.
1586 to the primary function; now copy the inline bits to
1587 the various clones. */
1589 {
1596 }
1600 }
1601 }
1603 {
1606 /* We've already complained in duplicate_decls. */
1610 /* Dup decl failed, but this is a new definition. Set the
1611 line number so any errors match this new
1612 definition. */
1616 }
1617 }
1621 /* A specialization must be declared in the same namespace as the
1622 template it is specializing. */
1628 {
1637 /* If TMPL is a forward declaration of a template function, keep a list
1638 of all specializations in case we need to reassign them to a friend
1639 template later in tsubst_friend_function.
1641 Also keep a list of all variable template instantiations so that
1642 process_partial_specialization can check whether a later partial
1643 specialization would have used it. */
1646 }
1649 }
1651 /* Returns true iff two spec_entry nodes are equivalent. */
1655 bool
1657 {
1664 /* tmpl could be a FIELD_DECL for a capture pack. */
1668 {
1669 /* Partial specializations of a variable template can be distinguished by
1670 constraints. */
1674 }
1678 }
1680 /* Returns a hash for a template TMPL and template arguments ARGS. */
1682 static hashval_t
1684 {
1687 }
1689 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1690 ignoring SPEC. */
1692 hashval_t
1694 {
1696 }
1698 /* Recursively calculate a hash value for a template argument ARG, for use
1699 in the hash tables of template specializations. */
1701 hashval_t
1703 {
1723 {
1731 {
1736 }
1758 {
1762 {
1765 }
1767 }
1771 {
1774 }
1785 val = iterative_hash_template_arg
1797 val);
1799 val);
1808 /* A lambda can't appear in a template arg, but don't crash on
1809 erroneous input. */
1821 /* Now hash operands as usual. */
1826 }
1829 {
1832 {
1833 // We want an alias specialization that survived strip_typedefs
1834 // to hash differently from its TYPE_CANONICAL, to avoid hash
1835 // collisions that compare as different in template_args_equal.
1836 // These could be dependent specializations that strip_typedefs
1837 // left alone, or untouched specializations because
1838 // coerce_template_parms returns the unconverted template
1839 // arguments if it sees incomplete argument packs.
1842 }
1845 val);
1848 /* Otherwise just compare the types during lookup. */
1857 {
1862 }
1863 }
1866 }
1868 /* Unregister the specialization SPEC as a specialization of TMPL.
1869 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1870 if the SPEC was listed as a specialization of TMPL.
1872 Note that SPEC has been ggc_freed, so we can't look inside it. */
1874 bool
1876 {
1878 spec_entry elt;
1886 {
1891 }
1894 }
1896 /* Like register_specialization, but for local declarations. We are
1897 registering SPEC, an instantiation of TMPL. */
1899 void
1901 {
1904 }
1906 /* TYPE is a class type. Returns true if TYPE is an explicitly
1907 specialized class. */
1909 bool
1911 {
1915 }
1917 /* Print the list of functions at FNS, going through all the overloads
1918 for each element of the list. Alternatively, FNS can not be a
1919 TREE_LIST, in which case it will be printed together with all the
1920 overloads.
1922 MORE and *STR should respectively be FALSE and NULL when the function
1923 is called from the outside. They are used internally on recursive
1924 calls. print_candidates manages the two parameters and leaves NULL
1925 in *STR when it ends. */
1927 static void
1929 {
1933 else
1935 {
1941 {
1944 else
1947 }
1949 }
1950 }
1952 /* Print the list of candidate FNS in an error message. FNS can also
1953 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1955 void
1957 {
1961 }
1963 /* Get a (possibly) constrained template declaration for the
1964 purpose of ordering candidates. */
1965 static tree
1967 {
1973 }
1975 /* Among candidates having the same signature, return the
1976 most constrained or NULL_TREE if there is no best candidate.
1977 If the signatures of candidates vary (e.g., template
1978 specialization vs. member function), then there can be no
1979 most constrained.
1981 Note that we don't compare constraints on the functions
1982 themselves, but rather those of their templates. */
1983 static tree
1985 {
1986 // Try to find the best candidate in a first pass.
1989 {
1996 }
1998 // Verify that the champ is better than previous candidates.
2003 }
2006 }
2009 /* Returns the template (one of the functions given by TEMPLATE_ID)
2010 which can be specialized to match the indicated DECL with the
2011 explicit template args given in TEMPLATE_ID. The DECL may be
2012 NULL_TREE if none is available. In that case, the functions in
2013 TEMPLATE_ID are non-members.
2015 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2016 specialization of a member template.
2018 The TEMPLATE_COUNT is the number of references to qualifying
2019 template classes that appeared in the name of the function. See
2020 check_explicit_specialization for a more accurate description.
2022 TSK indicates what kind of template declaration (if any) is being
2023 declared. TSK_TEMPLATE indicates that the declaration given by
2024 DECL, though a FUNCTION_DECL, has template parameters, and is
2025 therefore a template function.
2027 The template args (those explicitly specified and those deduced)
2028 are output in a newly created vector *TARGS_OUT.
2030 If it is impossible to determine the result, an error message is
2031 issued. The error_mark_node is returned to indicate failure. */
2033 static tree
2035 tree decl,
2039 tmpl_spec_kind tsk)
2040 {
2041 tree fns;
2042 tree targs;
2043 tree explicit_targs;
2046 /* A TREE_LIST of templates of which DECL may be a specialization.
2047 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2048 corresponding TREE_PURPOSE is the set of template arguments that,
2049 when used to instantiate the template, would produce a function
2050 with the signature of DECL. */
2060 /* We shouldn't be specializing a member template of an
2061 unspecialized class template; we already gave an error in
2062 check_specialization_scope, now avoid crashing. */
2065 {
2068 }
2076 /* Check for baselinks. */
2081 {
2084 }
2086 {
2089 }
2091 /* Count the number of template headers specified for this
2092 specialization. */
2102 {
2105 tf_warning_or_error,
2109 }
2111 {
2115 {
2116 tree decl_arg_types;
2117 tree fn_arg_types;
2118 tree insttype;
2120 /* In case of explicit specialization, we need to check if
2121 the number of template headers appearing in the specialization
2122 is correct. This is usually done in check_explicit_specialization,
2123 but the check done there cannot be exhaustive when specializing
2124 member functions. Consider the following code:
2126 template <> void A<int>::f(int);
2127 template <> template <> void A<int>::f(int);
2129 Assuming that A<int> is not itself an explicit specialization
2130 already, the first line specializes "f" which is a non-template
2131 member function, whilst the second line specializes "f" which
2132 is a template member function. So both lines are syntactically
2133 correct, and check_explicit_specialization does not reject
2134 them.
2136 Here, we can do better, as we are matching the specialization
2137 against the declarations. We count the number of template
2138 headers, and we check if they match TEMPLATE_COUNT + 1
2139 (TEMPLATE_COUNT is the number of qualifying template classes,
2140 plus there must be another header for the member template
2141 itself).
2143 Notice that if header_count is zero, this is not a
2144 specialization but rather a template instantiation, so there
2145 is no check we can perform here. */
2149 /* Check that the number of template arguments at the
2150 innermost level for DECL is the same as for FN. */
2158 /* DECL might be a specialization of FN. */
2162 /* For a non-static member function, we need to make sure
2163 that the const qualification is the same. Since
2164 get_bindings does not try to merge the "this" parameter,
2165 we must do the comparison explicitly. */
2171 /* Skip the "this" parameter and, for constructors of
2172 classes with virtual bases, the VTT parameter. A
2173 full specialization of a constructor will have a VTT
2174 parameter, but a template never will. */
2175 decl_arg_types
2177 fn_arg_types
2180 /* Function templates cannot be specializations; there are
2181 no partial specializations of functions. Therefore, if
2182 the type of DECL does not match FN, there is no
2183 match.
2185 Note that it should never be the case that we have both
2186 candidates added here, and for regular member functions
2187 below. */
2189 {
2193 }
2195 /* See whether this function might be a specialization of this
2196 template. Suppress access control because we might be trying
2197 to make this specialization a friend, and we have already done
2198 access control for the declaration of the specialization. */
2204 /* We cannot deduce template arguments that when used to
2205 specialize TMPL will produce DECL. */
2209 /* We deduced something involving 'auto', which isn't a valid
2210 template argument. */
2213 /* Remove, from the set of candidates, all those functions
2214 whose constraints are not satisfied. */
2218 // Then, try to form the new function type.
2222 fn_arg_types
2227 /* Save this template, and the arguments deduced. */
2229 }
2231 /* FN is an ordinary member function, and we need a
2232 specialization of a member template. */
2233 ;
2235 /* We can get IDENTIFIER_NODEs here in certain erroneous
2236 cases. */
2237 ;
2239 /* This is just an ordinary non-member function. Nothing can
2240 be a specialization of that. */
2241 ;
2243 /* Cannot specialize functions that are created implicitly. */
2244 ;
2245 else
2246 {
2247 tree decl_arg_types;
2249 /* This is an ordinary member function. However, since
2250 we're here, we can assume its enclosing class is a
2251 template class. For example,
2253 template <typename T> struct S { void f(); };
2254 template <> void S<int>::f() {}
2256 Here, S<int>::f is a non-template, but S<int> is a
2257 template class. If FN has the same type as DECL, we
2258 might be in business. */
2261 /* Its enclosing class is an explicit specialization
2262 of a template class. This is not a candidate. */
2267 /* The return types differ. */
2270 /* Adjust the type of DECL in case FN is a static member. */
2277 decl_arg_types))
2280 // If the deduced arguments do not satisfy the constraints,
2281 // this is not a candidate.
2285 // Add the candidate.
2287 }
2288 }
2291 {
2292 /* We have:
2294 [temp.expl.spec]
2296 It is possible for a specialization with a given function
2297 signature to be instantiated from more than one function
2298 template. In such cases, explicit specification of the
2299 template arguments must be used to uniquely identify the
2300 function template specialization being specialized.
2302 Note that here, there's no suggestion that we're supposed to
2303 determine which of the candidate templates is most
2304 specialized. However, we, also have:
2306 [temp.func.order]
2308 Partial ordering of overloaded function template
2309 declarations is used in the following contexts to select
2310 the function template to which a function template
2311 specialization refers:
2313 -- when an explicit specialization refers to a function
2314 template.
2316 So, we do use the partial ordering rules, at least for now.
2317 This extension can only serve to make invalid programs valid,
2318 so it's safe. And, there is strong anecdotal evidence that
2319 the committee intended the partial ordering rules to apply;
2320 the EDG front end has that behavior, and John Spicer claims
2321 that the committee simply forgot to delete the wording in
2322 [temp.expl.spec]. */
2325 {
2328 }
2329 }
2331 // Concepts allows multiple declarations of member functions
2332 // with the same signature. Like above, we need to rely on
2333 // on the partial ordering of those candidates to determine which
2334 // is the best.
2336 {
2338 {
2341 }
2342 }
2345 {
2352 else
2355 }
2359 {
2365 }
2367 /* We have one, and exactly one, match. */
2369 {
2373 // Propagate the candidate's constraints to the declaration.
2376 /* DECL is a re-declaration or partial instantiation of a template
2377 function. */
2380 /* It was a specialization of an ordinary member function in a
2381 template class. */
2383 }
2385 /* It was a specialization of a template. */
2388 {
2393 }
2394 else
2397 }
2399 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2400 but with the default argument values filled in from those in the
2401 TMPL_TYPES. */
2403 static tree
2405 tree tmpl_types)
2406 {
2407 tree new_spec_types;
2415 /* Substitute into the rest of the list. */
2416 new_spec_types =
2420 /* Add the default argument for this parameter. */
2423 new_spec_types);
2424 }
2426 /* DECL is an explicit specialization. Replicate default arguments
2427 from the template it specializes. (That way, code like:
2429 template <class T> void f(T = 3);
2430 template <> void f(double);
2431 void g () { f (); }
2433 works, as required.) An alternative approach would be to look up
2434 the correct default arguments at the call-site, but this approach
2435 is consistent with how implicit instantiations are handled. */
2437 static void
2439 {
2440 tree tmpl;
2441 tree spec_types;
2442 tree tmpl_types;
2443 tree new_spec_types;
2444 tree old_type;
2445 tree new_type;
2446 tree t;
2451 /* See if there's anything we need to do. */
2464 {
2465 /* Remove the this pointer, but remember the object's type for
2466 CV quals. */
2472 {
2473 /* DECL may contain more parameters than TMPL due to the extra
2474 in-charge parameter in constructors and destructors. */
2477 }
2479 {
2482 }
2483 }
2485 /* Compute the merged default arguments. */
2486 new_spec_types =
2489 /* Compute the new FUNCTION_TYPE. */
2491 {
2495 new_spec_types);
2498 /* Put the in-charge parameter back. */
2501 new_spec_types);
2505 new_spec_types);
2506 }
2507 else
2509 new_spec_types);
2519 }
2521 /* Return the number of template headers we expect to see for a definition
2522 or specialization of CTYPE or one of its non-template members. */
2524 int
2526 {
2530 {
2531 /* You're supposed to have one `template <...>' for every
2532 template class, but you don't need one for a full
2533 specialization. For example:
2535 template <class T> struct S{};
2536 template <> struct S<int> { void f(); };
2537 void S<int>::f () {}
2539 is correct; there shouldn't be a `template <>' for the
2540 definition of `S<int>::f'. */
2542 /* If CTYPE does not have template information of any
2543 kind, then it is not a template, nor is it nested
2544 within a template. */
2552 }
2555 }
2557 /* Do a simple sanity check on the template headers that precede the
2558 variable declaration DECL. */
2560 void
2562 {
2567 {
2570 "variable templates only available with "
2573 // Namespace-scope variable templates should have a template header.
2575 }
2577 {
2579 "too many template headers for %qD "
2585 "members of an explicitly specialized class are defined "
2587 }
2588 }
2590 /* An explicit specialization whose declarator-id or class-head-name is not
2591 qualified shall be declared in the nearest enclosing namespace of the
2592 template, or, if the namespace is inline (7.3.1), any namespace from its
2593 enclosing namespace set.
2595 If the name declared in the explicit instantiation is an unqualified name,
2596 the explicit instantiation shall appear in the namespace where its template
2597 is declared or, if that namespace is inline (7.3.1), any namespace from its
2598 enclosing namespace set. */
2600 void
2602 {
2607 {
2613 /* This was allowed in C++98, so only pedwarn. */
2615 "outside its namespace must use a nested-name-"
2617 }
2618 }
2620 /* Warn for a template specialization SPEC that is missing some of a set
2621 of function or type attributes that the template TEMPL is declared with.
2622 ATTRLIST is a list of additional attributes that SPEC should be taken
2623 to ultimately be declared with. */
2625 static void
2627 {
2634 /* Avoid warning if either declaration or its type is deprecated. */
2656 /* Avoid warning if the primary has no attributes. */
2660 /* Avoid warning if either declaration contains an attribute on
2661 the white list below. */
2664 };
2672 /* Avoid warning if the difference between the primary and
2673 the specialization is not in one of the attributes below. */
2677 };
2679 /* Put together a list of the black listed attributes that the primary
2680 template is declared with that the specialization is not, in case
2681 it's not apparent from the most recent declaration of the primary. */
2683 pretty_printer str;
2686 {
2688 {
2693 {
2703 }
2704 }
2705 }
2712 spec))
2718 }
2720 /* Check to see if the function just declared, as indicated in
2721 DECLARATOR, and in DECL, is a specialization of a function
2722 template. We may also discover that the declaration is an explicit
2723 instantiation at this point.
2725 Returns DECL, or an equivalent declaration that should be used
2726 instead if all goes well. Issues an error message if something is
2727 amiss. Returns error_mark_node if the error is not easily
2728 recoverable.
2730 FLAGS is a bitmask consisting of the following flags:
2732 2: The function has a definition.
2733 4: The function is a friend.
2735 The TEMPLATE_COUNT is the number of references to qualifying
2736 template classes that appeared in the name of the function. For
2737 example, in
2739 template <class T> struct S { void f(); };
2740 void S<int>::f();
2742 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2743 classes are not counted in the TEMPLATE_COUNT, so that in
2745 template <class T> struct S {};
2746 template <> struct S<int> { void f(); }
2747 template <> void S<int>::f();
2749 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2750 invalid; there should be no template <>.)
2752 If the function is a specialization, it is marked as such via
2753 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2754 is set up correctly, and it is added to the list of specializations
2755 for that template. */
2757 tree
2759 tree decl,
2762 tree attrlist)
2763 {
2772 tmpl_spec_kind tsk;
2775 {
2778 else
2780 }
2781 else
2785 {
2788 {
2791 }
2793 {
2795 /* This could be something like:
2797 template <class T> void f(T);
2798 class S { friend void f<>(int); } */
2800 else
2801 {
2802 /* This case handles bogus declarations like template <>
2803 template <class T> void f<int>(); */
2806 declarator);
2808 }
2809 }
2813 /* The error has already been reported in
2814 check_specialization_scope. */
2820 /* Fall through. */
2833 decl);
2836 else
2840 /* Fall through. */
2846 /* In cases like template<> constexpr bool v = true;
2847 We'll give an error in check_template_variable. */
2853 else
2859 {
2860 /* This case handles bogus declarations like template <>
2861 template <class T> void f<int>(); */
2865 declarator);
2867 {
2868 /* Partial specialization of variable template. */
2872 }
2876 else
2880 ok:;
2881 }
2884 /* This is a specialization of a member template, without
2885 specialization the containing class. Something like:
2887 template <class T> struct S {
2888 template <class U> void f (U);
2889 };
2890 template <> template <class U> void S<int>::f(U) {}
2892 That's a specialization -- but of the entire template. */
2898 }
2901 /* This doesn't apply to variable templates. */
2904 {
2908 {
2912 }
2913 }
2916 {
2921 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2923 {
2924 tree fns;
2929 else
2930 {
2931 /* If there is no class context, the explicit instantiation
2932 must be at namespace scope. */
2935 /* Find the namespace binding, using the declaration
2936 context. */
2940 /* If lookup fails, look for a friend declaration so we can
2941 give a better diagnostic. */
2947 {
2950 }
2951 }
2954 }
2960 {
2962 /* A specialization in class scope. This is invalid,
2963 but the error will already have been flagged by
2964 check_specialization_scope. */
2966 else
2967 {
2968 /* It's not valid to write an explicit instantiation in
2969 class scope, e.g.:
2971 class C { template void f(); }
2973 This case is caught by the parser. However, on
2974 something like:
2976 template class C { void f(); };
2978 (which is invalid) we can get here. The error will be
2979 issued later. */
2980 ;
2981 }
2984 }
2987 {
2988 // We'll match variable templates in start_decl.
2992 /* Find the list of functions in ctype that have the same
2993 name as the declared function. */
2997 {
3001 {
3002 /* From [temp.expl.spec]:
3004 If such an explicit specialization for the member
3005 of a class template names an implicitly-declared
3006 special member function (clause _special_), the
3007 program is ill-formed.
3009 Similar language is found in [temp.explicit]. */
3012 }
3015 }
3017 /* For a type-conversion operator, We might be looking for
3018 `operator int' which will be a specialization of
3019 `operator T'. Grab all the conversion operators, and
3020 then select from them. */
3025 {
3028 }
3029 else
3031 }
3033 /* Figure out what exactly is being specialized at this point.
3034 Note that for an explicit instantiation, even one for a
3035 member function, we cannot tell a priori whether the
3036 instantiation is for a member template, or just a member
3037 function of a template class. Even if a member template is
3038 being instantiated, the member template arguments may be
3039 elided if they can be deduced from the rest of the
3040 declaration. */
3043 member_specialization,
3044 template_count,
3045 tsk);
3048 /* We couldn't figure out what this declaration was
3049 specializing. */
3051 else
3052 {
3055 {
3057 "friend declaration %qD is not visible to "
3061 }
3069 {
3070 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3071 is done by do_decl_instantiation later. */
3077 {
3078 /* If TMPL is not the most general template (for
3079 example, if TMPL is a friend template that is
3080 injected into namespace scope), then there will
3081 be too many levels of TARGS. Remove some of them
3082 here. */
3084 tree new_targs;
3091 }
3094 }
3096 /* If we thought that the DECL was a member function, but it
3097 turns out to be specializing a static member function,
3098 make DECL a static member function as well. */
3104 /* If this is a specialization of a member template of a
3105 template class, we want to return the TEMPLATE_DECL, not
3106 the specialization of it. */
3108 {
3113 {
3114 tree parm;
3118 /* We want to use the argument list specified in the
3119 definition, not in the original declaration. */
3124 }
3127 }
3129 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3135 /* Inherit default function arguments from the template
3136 DECL is specializing. */
3140 /* This specialization has the same protection as the
3141 template it specializes. */
3145 /* 7.1.1-1 [dcl.stc]
3147 A storage-class-specifier shall not be specified in an
3148 explicit specialization...
3150 The parser rejects these, so unless action is taken here,
3151 explicit function specializations will always appear with
3152 global linkage.
3154 The action recommended by the C++ CWG in response to C++
3155 defect report 605 is to make the storage class and linkage
3156 of the explicit specialization match the templated function:
3158 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3159 */
3161 {
3165 /* A concept cannot be specialized. */
3167 {
3169 gen_tmpl);
3171 }
3173 /* This specialization has the same linkage and visibility as
3174 the function template it specializes. */
3177 {
3180 }
3183 {
3186 }
3187 }
3189 /* If DECL is a friend declaration, declared using an
3190 unqualified name, the namespace associated with DECL may
3191 have been set incorrectly. For example, in:
3193 template <typename T> void f(T);
3194 namespace N {
3195 struct S { friend void f<int>(int); }
3196 }
3198 we will have set the DECL_CONTEXT for the friend
3199 declaration to N, rather than to the global namespace. */
3204 /* This is not really a declaration of a specialization.
3205 It's just the name of an instantiation. But, it's not
3206 a request for an instantiation, either. */
3209 /* A specialization is not necessarily COMDAT. */
3215 /* If this is a full specialization, register it so that we can find
3216 it again. Partial specializations will be registered in
3217 process_partial_specialization. */
3219 {
3224 }
3227 /* A 'structor should already have clones. */
3233 }
3234 }
3237 }
3239 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3240 parameters. These are represented in the same format used for
3241 DECL_TEMPLATE_PARMS. */
3243 int
3245 {
3246 const_tree p1;
3247 const_tree p2;
3255 {
3267 {
3271 /* If either of the template parameters are invalid, assume
3272 they match for the sake of error recovery. */
3285 }
3286 }
3289 /* One set of parameters has more parameters lists than the
3290 other. */
3294 }
3296 /* Determine whether PARM is a parameter pack. */
3298 bool
3300 {
3301 /* Determine if we have a non-type template parameter pack. */
3308 /* If this is a list of template parameters, we could get a
3309 TYPE_DECL or a TEMPLATE_DECL. */
3313 /* Otherwise it must be a type template parameter. */
3317 }
3319 /* Determine if T is a function parameter pack. */
3321 bool
3323 {
3327 }
3329 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3330 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3332 tree
3334 {
3341 }
3343 /* Return true iff the function parameter PARAM_DECL was expanded
3344 from the function parameter pack PACK. */
3346 bool
3348 {
3353 /* The parameter pack and its pack arguments have the same
3354 DECL_PARM_INDEX. */
3356 }
3358 /* Determine whether ARGS describes a variadic template args list,
3359 i.e., one that is terminated by a template argument pack. */
3361 static bool
3363 {
3365 tree last_parm;
3379 }
3381 /* Generate a new name for the parameter pack name NAME (an
3382 IDENTIFIER_NODE) that incorporates its */
3384 static tree
3386 {
3387 /* Munge the name to include the parameter index. */
3388 #define NUMBUF_LEN 128
3402 }
3404 /* Return true if T is a primary function, class or alias template
3405 specialization, not including the template pattern. */
3407 bool
3409 {
3425 }
3427 /* Return true if PARM is a template template parameter. */
3429 bool
3431 {
3433 }
3435 /* Return true iff PARM is a DECL representing a type template
3436 parameter. */
3438 bool
3440 {
3445 }
3447 /* Return the template parameters of T if T is a
3448 primary template instantiation, NULL otherwise. */
3450 tree
3452 {
3457 parms = INNERMOST_TEMPLATE_PARMS
3461 }
3463 /* Return the template parameters of the LEVELth level from the full list
3464 of template parameters PARMS. */
3466 tree
3468 {
3469 tree p;
3480 }
3482 /* Returns the template arguments of T if T is a template instantiation,
3483 NULL otherwise. */
3485 tree
3487 {
3495 }
3497 /* Return the argument pack elements of T if T is a template argument pack,
3498 NULL otherwise. */
3500 tree
3502 {
3508 }
3510 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3511 ARGUMENT_PACK_SELECT represents. */
3513 static tree
3515 {
3519 /* If the selected argument is an expansion E, that most likely means we were
3520 called from gen_elem_of_pack_expansion_instantiation during the
3521 substituting of an argument pack (of which the Ith element is a pack
3522 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3523 In this case, the Ith element resulting from this substituting is going to
3524 be a pack expansion, which pattern is the pattern of E. Let's return the
3525 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3526 resulting pack expansion from it. */
3528 {
3529 /* Make sure we aren't throwing away arg info. */
3532 }
3535 }
3538 /* True iff FN is a function representing a built-in variadic parameter
3539 pack. */
3541 bool
3543 {
3553 }
3555 /* True iff CALL is a call to a function representing a built-in variadic
3556 parameter pack. */
3558 static bool
3560 {
3564 }
3566 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3568 static tree
3570 tree in_decl)
3571 {
3577 {
3579 {
3582 }
3587 }
3588 else
3589 {
3593 /* Calculate the largest value of len that won't make the size of the vec
3594 overflow an int. The compiler will exceed resource limits long before
3595 this, but it seems a decent place to diagnose. */
3599 {
3604 }
3612 }
3613 }
3615 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3616 CALL. */
3618 static tree
3620 tree in_decl)
3621 {
3631 }
3633 /* Structure used to track the progress of find_parameter_packs_r. */
3634 struct find_parameter_pack_data
3635 {
3636 /* TREE_LIST that will contain all of the parameter packs found by
3637 the traversal. */
3640 /* Set of AST nodes that have been visited by the traversal. */
3643 /* True iff we're making a type pack expansion. */
3645 };
3647 /* Identifies all of the argument packs that occur in a template
3648 argument and appends them to the TREE_LIST inside DATA, which is a
3649 find_parameter_pack_data structure. This is a subroutine of
3650 make_pack_expansion and uses_parameter_packs. */
3651 static tree
3653 {
3659 /* Handle type aliases/typedefs. */
3661 {
3668 }
3670 /* Identify whether this is a parameter pack or not. */
3672 {
3680 /* FALLTHRU */
3682 /* If the placeholder appears in the decl-specifier-seq of a function
3683 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3684 is a pack expansion, the invented template parameter is a template
3685 parameter pack. */
3695 {
3696 /* We don't want to walk into the type of a PARM_DECL,
3697 because we don't want to see the type parameter pack. */
3700 }
3705 {
3706 /* We don't want to walk into the type of a variadic capture proxy,
3707 because we don't want to see the type parameter pack. */
3710 }
3712 {
3714 find_parameter_packs_r,
3717 }
3729 /* Not a parameter pack. */
3731 }
3734 {
3735 /* Add this parameter pack to the list. */
3737 }
3743 /* This switch statement will return immediately if we don't find a
3744 parameter pack. */
3746 {
3751 /* Check the template itself. */
3754 /* Check the template arguments. */
3768 /* Ignore the declaration of a capture proxy for a parameter pack. */
3776 /* Fall through. */
3821 {
3822 /* Look at explicit captures. */
3827 /* Since we defer implicit capture, look in the body as well. */
3833 }
3836 {
3837 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3838 type_pack_expansion_p to false so that any placeholders
3839 within the expression don't get marked as parameter packs. */
3847 }
3851 }
3854 }
3856 /* Determines if the expression or type T uses any parameter packs. */
3857 bool
3859 {
3868 }
3870 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3871 representation a base-class initializer into a parameter pack
3872 expansion. If all goes well, the resulting node will be an
3873 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3874 respectively. */
3875 tree
3877 {
3878 tree result;
3887 {
3888 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3889 class initializer. In this case, the TREE_PURPOSE will be a
3890 _TYPE node (representing the base class expansion we're
3891 initializing) and the TREE_VALUE will be a TREE_LIST
3892 containing the initialization arguments.
3894 The resulting expansion looks somewhat different from most
3895 expansions. Rather than returning just one _EXPANSION, we
3896 return a TREE_LIST whose TREE_PURPOSE is a
3897 TYPE_PACK_EXPANSION containing the bases that will be
3898 initialized. The TREE_VALUE will be identical to the
3899 original TREE_VALUE, which is a list of arguments that will
3900 be passed to each base. We do not introduce any new pack
3901 expansion nodes into the TREE_VALUE (although it is possible
3902 that some already exist), because the TREE_PURPOSE and
3903 TREE_VALUE all need to be expanded together with the same
3904 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3905 resulting TREE_PURPOSE will mention the parameter packs in
3906 both the bases and the arguments to the bases. */
3907 tree purpose;
3908 tree value;
3911 /* Determine which parameter packs will be used by the base
3912 class expansion. */
3921 {
3924 arg);
3927 }
3930 {
3931 /* Collect the sets of parameter packs used in each of the
3932 initialization arguments. */
3934 {
3935 /* Determine which parameter packs will be expanded in this
3936 argument. */
3939 }
3940 }
3944 /* Create the pack expansion type for the base type. */
3950 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3951 they will rarely be compared to anything. */
3955 }
3960 /* Build the PACK_EXPANSION_* node. */
3961 result = for_types
3966 {
3967 /* Propagate type and const-expression information. */
3970 /* Mark this read now, since the expansion might be length 0. */
3972 }
3973 else
3974 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3975 they will rarely be compared to anything. */
3978 /* Determine which parameter packs will be expanded. */
3985 /* Make sure we found some parameter packs. */
3987 {
3989 {
3992 else
3994 }
3996 }
4002 }
4004 /* Checks T for any "bare" parameter packs, which have not yet been
4005 expanded, and issues an error if any are found. This operation can
4006 only be done on full expressions or types (e.g., an expression
4007 statement, "if" condition, etc.), because we could have expressions like:
4009 foo(f(g(h(args)))...)
4011 where "args" is a parameter pack. check_for_bare_parameter_packs
4012 should not be called for the subexpressions args, h(args),
4013 g(h(args)), or f(g(h(args))), because we would produce erroneous
4014 error messages.
4016 Returns TRUE and emits an error if there were bare parameter packs,
4017 returns FALSE otherwise. */
4018 bool
4020 {
4027 /* A lambda might use a parameter pack from the containing context. */
4041 {
4045 {
4056 else
4061 else
4065 }
4068 }
4071 }
4073 /* Expand any parameter packs that occur in the template arguments in
4074 ARGS. */
4075 tree
4077 {
4086 /* First, determine if we need to expand anything, and the number of
4087 slots we'll need. */
4089 {
4094 {
4098 else
4100 }
4101 else
4102 {
4104 num_result_args++;
4105 }
4106 }
4108 /* If no expansion is necessary, we're done. */
4112 /* Expand arguments. */
4115 non_default_args_count =
4118 {
4121 {
4128 }
4129 else
4130 {
4133 }
4134 }
4138 }
4140 /* Checks if DECL shadows a template parameter.
4142 [temp.local]: A template-parameter shall not be redeclared within its
4143 scope (including nested scopes).
4145 Emits an error and returns TRUE if the DECL shadows a parameter,
4146 returns FALSE otherwise. */
4148 bool
4150 {
4151 tree olddecl;
4153 /* If we're not in a template, we can't possibly shadow a template
4154 parameter. */
4158 /* Figure out what we're shadowing. */
4162 /* If there's no previous binding for this name, we're not shadowing
4163 anything, let alone a template parameter. */
4167 /* If we're not shadowing a template parameter, we're done. Note
4168 that OLDDECL might be an OVERLOAD (or perhaps even an
4169 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4170 node. */
4174 /* We check for decl != olddecl to avoid bogus errors for using a
4175 name inside a class. We check TPFI to avoid duplicate errors for
4176 inline member templates. */
4182 /* Don't complain about the injected class name, as we've already
4183 complained about the class itself. */
4190 else
4195 }
4197 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4198 ORIG_LEVEL, DECL, and TYPE. */
4200 static tree
4204 tree decl,
4205 tree type)
4206 {
4217 }
4219 /* Find the canonical type parameter for the given template type
4220 parameter. Returns the canonical type parameter, which may be TYPE
4221 if no such parameter existed. */
4223 static tree
4225 {
4226 tree list;
4240 else
4241 {
4245 }
4246 }
4248 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4249 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4250 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4251 new one is created. */
4253 static tree
4255 tsubst_flags_t complain)
4256 {
4261 {
4280 /* Template template parameters need this. */
4282 {
4289 }
4290 }
4293 }
4295 /* Process information from new template parameter PARM and append it
4296 to the LIST being built. This new parameter is a non-type
4297 parameter iff IS_NON_TYPE is true. This new parameter is a
4298 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4299 is in PARM_LOC. */
4301 tree
4304 {
4313 {
4317 {
4321 else
4323 }
4326 }
4329 {
4335 {
4336 /* [temp.param]
4338 The top-level cv-qualifiers on the template-parameter are
4339 ignored when determining its type. */
4344 && !is_parameter_pack
4345 /* If we're in a nested template parameter list, the template
4346 template parameter could be a parameter pack. */
4348 {
4349 /* This template parameter is not a parameter pack, but it
4350 should be. Complain about "bare" parameter packs. */
4353 /* Recover by calling this a parameter pack. */
4355 }
4356 }
4358 /* A template parameter is not modifiable. */
4367 processing_template_decl,
4372 }
4373 else
4374 {
4375 tree t;
4379 {
4381 /* This is for distinguishing between real templates and template
4382 template parameters */
4386 }
4387 else
4388 {
4390 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4393 }
4400 processing_template_decl,
4404 }
4408 /* Build requirements for the type/template parameter.
4409 This must be done after SET_DECL_TEMPLATE_PARM_P or
4410 process_template_parm could fail. */
4415 /* Build the parameter node linking the parameter declaration,
4416 its default argument (if any), and its constraints (if any). */
4421 }
4423 /* The end of a template parameter list has been reached. Process the
4424 tree list into a parameter vector, converting each parameter into a more
4425 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4426 as PARM_DECLs. */
4428 tree
4430 {
4435 /* Pop the dummy parameter level and add the real one. */
4438 current_template_parms
4443 {
4447 }
4452 }
4454 // Explicitly indicate the end of the template parameter list. We assume
4455 // that the current template parameters have been constructed and/or
4456 // managed explicitly, as when creating new template template parameters
4457 // from a shorthand constraint.
4458 void
4460 {
4462 }
4464 /* end_template_decl is called after a template declaration is seen. */
4466 void
4468 {
4474 /* This matches the pushlevel in begin_template_parm_list. */
4479 }
4481 /* Takes a TREE_LIST representing a template parameter and convert it
4482 into an argument suitable to be passed to the type substitution
4483 functions. Note that If the TREE_LIST contains an error_mark
4484 node, the returned argument is error_mark_node. */
4486 tree
4488 {
4501 {
4505 {
4506 /* Turn this argument into a TYPE_ARGUMENT_PACK
4507 with a single element, which expands T. */
4516 }
4517 }
4518 else
4519 {
4523 {
4524 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4525 with a single element, which expands T. */
4535 }
4536 else
4538 }
4540 }
4542 /* Given a single level of template parameters (a TREE_VEC), return it
4543 as a set of template arguments. */
4545 static tree
4547 {
4557 }
4559 /* Given a set of template parameters, return them as a set of template
4560 arguments. The template parameters are represented as a TREE_VEC, in
4561 the form documented in cp-tree.h for template arguments. */
4563 static tree
4565 {
4566 tree header;
4571 /* If there is only one level of template parameters, we do not
4572 create a TREE_VEC of TREE_VECs. Instead, we return a single
4573 TREE_VEC containing the arguments. */
4578 {
4583 else
4585 }
4588 }
4590 /* Within the declaration of a template, return the currently active
4591 template parameters as an argument TREE_VEC. */
4593 static tree
4595 {
4597 }
4599 /* Update the declared TYPE by doing any lookups which were thought to be
4600 dependent, but are not now that we know the SCOPE of the declarator. */
4602 tree
4604 {
4615 /* Don't bother building up the args in this case. */
4617 {
4618 /* tsubst in the args corresponding to the template parameters,
4619 including auto if present. Most things will be unchanged, but
4620 make_typename_type and tsubst_qualified_id will resolve
4621 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4624 tree pushed;
4626 {
4630 }
4635 }
4641 {
4644 else
4646 }
4648 }
4650 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4651 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4652 the new template is a member template. */
4654 tree
4656 {
4664 }
4666 struct template_parm_data
4667 {
4668 /* The level of the template parameters we are currently
4669 processing. */
4672 /* The index of the specialization argument we are currently
4673 processing. */
4676 /* An array whose size is the number of template parameters. The
4677 elements are nonzero if the parameter has been used in any one
4678 of the arguments processed so far. */
4681 /* An array whose size is the number of template arguments. The
4682 elements are nonzero if the argument makes use of template
4683 parameters of this level. */
4685 };
4687 /* Subroutine of push_template_decl used to see if each template
4688 parameter in a partial specialization is used in the explicit
4689 argument list. If T is of the LEVEL given in DATA (which is
4690 treated as a template_parm_data*), then DATA->PARMS is marked
4691 appropriately. */
4693 static int
4695 {
4703 {
4706 }
4708 /* In C++17 the type of a non-type argument is a deduced context. */
4713 data,
4714 NULL,
4717 /* Return zero so that for_each_template_parm will continue the
4718 traversal of the tree; we want to mark *every* template parm. */
4720 }
4722 /* Process the partial specialization DECL. */
4724 static tree
4726 {
4733 tree inner_parms;
4734 tree inst;
4744 /* A concept cannot be specialized. */
4746 {
4749 }
4754 /* We check that each of the template parameters given in the
4755 partial specialization is used in the argument list to the
4756 specialization. For example:
4758 template <class T> struct S;
4759 template <class T> struct S<T*>;
4761 The second declaration is OK because `T*' uses the template
4762 parameter T, whereas
4764 template <class T> struct S<int>;
4766 is no good. Even trickier is:
4768 template <class T>
4769 struct S1
4770 {
4771 template <class U>
4772 struct S2;
4773 template <class U>
4774 struct S2<T>;
4775 };
4777 The S2<T> declaration is actually invalid; it is a
4778 full-specialization. Of course,
4780 template <class U>
4781 struct S2<T (*)(U)>;
4783 or some such would have been OK. */
4791 {
4796 NULL,
4798 }
4801 {
4802 /* One of the template parms was not used in a deduced context in the
4803 specialization. */
4805 {
4809 }
4813 }
4818 /* [temp.class.spec]
4820 The argument list of the specialization shall not be identical to
4821 the implicit argument list of the primary template. */
4822 tree main_args
4825 && (!flag_concepts
4828 {
4832 else
4836 }
4838 /* A partial specialization that replaces multiple parameters of the
4839 primary template with a pack expansion is less specialized for those
4840 parameters. */
4842 {
4844 "primary template because it replaces multiple parameters "
4847 /* Avoid crash in process_partial_specialization. */
4849 }
4851 /* If we aren't in a dependent class, we can actually try deduction. */
4853 /* FIXME we should be able to handle a partial specialization of a
4854 partial instantiation, but currently we can't (c++/41727). */
4857 {
4861 maintmpl);
4862 }
4864 /* [temp.class.spec]
4866 A partially specialized non-type argument expression shall not
4867 involve template parameters of the partial specialization except
4868 when the argument expression is a simple identifier.
4870 The type of a template parameter corresponding to a specialized
4871 non-type argument shall not be dependent on a parameter of the
4872 specialization.
4874 Also, we verify that pack expansions only occur at the
4875 end of the argument list. */
4879 {
4886 {
4887 /* Extract the arguments from the argument pack. We'll be
4888 iterating over these in the following loop. */
4891 }
4894 {
4896 /* Get the Jth argument in the parameter pack. */
4900 {
4901 /* Pack expansions must come at the end of the
4902 argument list. */
4905 {
4909 else
4912 }
4913 }
4916 /* We only care about the pattern. */
4922 /* This next two lines are the `argument expression is not just a
4923 simple identifier' condition and also the `specialized
4924 non-type argument' bit. */
4928 {
4932 arg);
4933 else
4934 {
4935 /* Look at the corresponding template parameter,
4936 marking which template parameters its type depends
4937 upon. */
4941 {
4942 /* We haven't yet initialized TPD2. Do so now. */
4944 /* The number of parameters here is the number in the
4945 main template, which, as checked in the assertion
4946 above, is NARGS. */
4950 }
4952 /* Mark the template parameters. But this time, we're
4953 looking for the template parameters of the main
4954 template, not in the specialization. */
4961 NULL,
4965 {
4966 /* The type depended on some template parameters.
4967 If they are fully specialized in the
4968 specialization, that's OK. */
4977 "type %qT of template argument %qE depends "
4979 "type %qT of template argument %qE depends "
4981 type,
4982 arg);
4983 }
4984 }
4985 }
4986 }
4987 }
4989 /* We should only get here once. */
4993 // Build the template decl.
5002 /* Give template template parms a DECL_CONTEXT of the template
5003 for which they are a parameter. */
5005 {
5009 }
5012 /* We didn't register this in check_explicit_specialization so we could
5013 wait until the constraints were set. */
5015 else
5025 {
5031 {
5039 "declaration of %qD ambiguates earlier template "
5043 "partial specialization of %qD after instantiation "
5045 }
5046 }
5049 }
5051 /* PARM is a template parameter of some form; return the corresponding
5052 TEMPLATE_PARM_INDEX. */
5054 static tree
5056 {
5069 }
5071 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5072 parameter packs used by the template parameter PARM. */
5074 static void
5076 {
5077 /* A type parm can't refer to another parm. */
5081 {
5085 }
5092 }
5094 /* PARM is a template parameter pack. Return any parameter packs used in
5095 its type or the type of any of its template parameters. If there are
5096 any such packs, it will be instantiated into a fixed template parameter
5097 list by partial instantiation rather than be fully deduced. */
5099 tree
5101 {
5102 /* This can only be true in a member template. */
5105 /* This can only be true for a parameter pack. */
5108 /* A type parm can't refer to another parm. */
5122 }
5124 /* Check that a template declaration's use of default arguments and
5125 parameter packs is not invalid. Here, PARMS are the template
5126 parameters. IS_PRIMARY is true if DECL is the thing declared by
5127 a primary template. IS_PARTIAL is true if DECL is a partial
5128 specialization.
5130 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5131 function template declaration or a friend class template
5132 declaration. In the function case, 1 indicates a declaration, 2
5133 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5134 emitted for extraneous default arguments.
5136 Returns TRUE if there were no errors found, FALSE otherwise. */
5138 bool
5141 {
5144 tree parm_level;
5147 /* [temp.param]
5149 A default template-argument shall not be specified in a
5150 function template declaration or a function template definition, nor
5151 in the template-parameter-list of the definition of a member of a
5152 class template. */
5156 /* You can't have a function template declaration in a local
5157 scope, nor you can you define a member of a class template in a
5158 local scope. */
5166 /* A lambda doesn't have an explicit declaration; don't complain
5167 about the parms of the enclosing class. */
5174 /* If this is either a friend defined in the scope of the class
5175 or a member function. */
5181 /* And, if it was a member function, it really was defined in
5182 the scope of the class. */
5185 /* We already checked these parameters when the template was
5186 declared, so there's no need to do it again now. This function
5187 was defined in class scope, but we're processing its body now
5188 that the class is complete. */
5191 /* Core issue 226 (C++0x only): the following only applies to class
5192 templates. */
5195 {
5196 /* [temp.param]
5198 If a template-parameter has a default template-argument, all
5199 subsequent template-parameters shall have a default
5200 template-argument supplied. */
5202 {
5209 {
5219 {
5221 /* For better subsequent error-recovery, we indicate that
5222 there should have been a default argument. */
5225 }
5227 && !is_friend_decl
5228 /* Don't complain about an enclosing partial
5229 specialization. */
5234 /* A fixed parameter pack will be partially
5235 instantiated into a fixed length list. */
5237 {
5238 /* A primary class template can only have one
5239 parameter pack, at the end of the template
5240 parameter list. */
5248 }
5249 }
5250 }
5251 }
5254 || is_partial
5255 || !is_primary
5257 /* For an ordinary class template, default template arguments are
5258 allowed at the innermost level, e.g.:
5259 template <class T = int>
5260 struct S {};
5261 but, in a partial specialization, they're not allowed even
5262 there, as we have in [temp.class.spec]:
5264 The template parameter list of a specialization shall not
5265 contain default template argument values.
5267 So, for a partial specialization, or for a function template
5268 (in C++98/C++03), we look at all of them. */
5269 ;
5270 else
5271 /* But, for a primary class template that is not a partial
5272 specialization we look at all template parameters except the
5273 innermost ones. */
5276 /* Figure out what error message to issue. */
5291 else
5292 /* Per [temp.param]/9, "A default template-argument shall not be
5293 specified in the template-parameter-lists of the definition of
5294 a member of a class template that appears outside of the member's
5295 class.", thus if we aren't handling a member of a class template
5296 there is no need to examine the parameters. */
5300 /* If we're inside a class definition, there's no need to
5301 examine the parameters to the class itself. On the one
5302 hand, they will be checked when the class is defined, and,
5303 on the other, default arguments are valid in things like:
5304 template <class T = double>
5305 struct S { template <class U> void f(U); };
5306 Here the default argument for `S' has no bearing on the
5307 declaration of `f'. */
5309 else
5310 /* Check everything. */
5316 {
5323 {
5328 {
5330 {
5337 }
5339 /* Clear out the default argument so that we are not
5340 confused later. */
5342 }
5343 }
5345 /* At this point, if we're still interested in issuing messages,
5346 they must apply to classes surrounding the object declared. */
5350 }
5353 }
5355 /* Worker for push_template_decl_real, called via
5356 for_each_template_parm. DATA is really an int, indicating the
5357 level of the parameters we are interested in. If T is a template
5358 parameter of that level, return nonzero. */
5360 static int
5362 {
5368 else
5371 }
5373 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5374 DATA is really an int, indicating the innermost outer level of parameters.
5375 If T is a template parameter of that level or further out, return
5376 nonzero. */
5378 static int
5380 {
5386 else
5389 }
5391 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5392 parameters given by current_template_args, or reuses a
5393 previously existing one, if appropriate. Returns the DECL, or an
5394 equivalent one, if it is replaced via a call to duplicate_decls.
5396 If IS_FRIEND is true, DECL is a friend declaration. */
5398 tree
5400 {
5401 tree tmpl;
5402 tree args;
5403 tree info;
5404 tree ctx;
5408 /* True if the template is a member template, in the sense of
5409 [temp.mem]. */
5415 /* See if this is a partial specialization. */
5428 /* For a friend, we want the context of the friend, not
5429 the type of which it is a friend. */
5433 /* In the case of a virtual function, we want the class in which
5434 it is defined. */
5436 else
5437 /* Otherwise, if we're currently defining some class, the DECL
5438 is assumed to be a member of the class. */
5447 /* See if this is a primary template. */
5450 /* A friend template that specifies a class context, i.e.
5451 template <typename T> friend void A<T>::f();
5452 is not primary. */
5457 else
5461 {
5468 {
5471 }
5473 {
5475 {
5478 }
5480 {
5481 /* [temp.mem]
5483 A destructor shall not be a member template. */
5486 }
5493 {
5494 /* [basic.stc.dynamic.allocation]
5496 An allocation function can be a function
5497 template. ... Template allocation functions shall
5498 have two or more parameters. */
5501 }
5502 }
5505 {
5506 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5509 {
5515 }
5516 }
5519 /* alias-declaration */
5523 else
5524 {
5527 }
5528 }
5530 /* Check to see that the rules regarding the use of default
5531 arguments are not being violated. We check args for a friend
5532 functions when we know whether it's a definition, introducing
5533 declaration or re-declaration. */
5538 /* Ensure that there are no parameter packs in the type of this
5539 declaration that have not been expanded. */
5541 {
5542 /* Check each of the arguments individually to see if there are
5543 any bare parameter packs. */
5549 {
5552 {
5553 /* This is a PARM_DECL that contains unexpanded parameter
5554 packs. We have already complained about this in the
5555 check_for_bare_parameter_packs call, so just replace
5556 these types with ERROR_MARK_NODE. */
5559 }
5563 }
5565 /* Check for bare parameter packs in the return type and the
5566 exception specifiers. */
5568 /* Errors were already issued, set return type to int
5569 as the frontend doesn't expect error_mark_node as
5570 the return type. */
5574 }
5579 {
5582 }
5595 {
5600 /* If DECL is a TYPE_DECL for a class-template, then there won't
5601 be DECL_LANG_SPECIFIC. The information equivalent to
5602 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5606 {
5607 /* Since a template declaration already existed for this
5608 class-type, we must be redeclaring it here. Make sure
5609 that the redeclaration is valid. */
5611 current_template_parms,
5613 /* We don't need to create a new TEMPLATE_DECL; just use the
5614 one we already had. */
5616 }
5617 else
5618 {
5620 member_template_p);
5625 {
5626 /* A specialization of a member template of a template
5627 class. */
5631 }
5632 }
5633 }
5634 else
5635 {
5641 {
5644 }
5652 {
5653 tree new_tmpl;
5655 /* The declaration is a specialization of a member
5656 template, declared outside the class. Therefore, the
5657 innermost template arguments will be NULL, so we
5658 replace them with the arguments determined by the
5659 earlier call to check_explicit_specialization. */
5662 new_tmpl
5664 member_template_p);
5674 args,
5677 }
5679 /* Make sure the template headers we got make sense. */
5684 {
5689 }
5690 else
5692 {
5697 {
5701 else
5705 /* Avoid crash in import_export_decl. */
5708 }
5713 /* Can happen in erroneous input. */
5715 else
5717 }
5719 /* Check that the parms are used in the appropriate qualifying scopes
5720 in the declarator. */
5724 {
5730 /* Avoid crash in import_export_decl. */
5733 }
5734 }
5739 /* Push template declarations for global functions and types. Note
5740 that we do not try to push a global template friend declared in a
5741 template class; such a thing may well depend on the template
5742 parameters of the class. */
5745 {
5750 /* Hide template friend classes that haven't been declared yet. */
5752 {
5755 }
5756 }
5759 {
5764 /* Give template template parms a DECL_CONTEXT of the template
5765 for which they are a parameter. */
5768 {
5772 }
5778 }
5780 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5781 back to its most general template. If TMPL is a specialization,
5782 ARGS may only have the innermost set of arguments. Add the missing
5783 argument levels if necessary. */
5791 else
5792 {
5797 }
5800 && !is_friend
5803 /* Set DECL_COMDAT on template instantiations; if we force
5804 them to be emitted by explicit instantiation or -frepo,
5805 mark_needed will tell cgraph to do the right thing. */
5809 }
5811 tree
5813 {
5815 }
5817 /* FN is an inheriting constructor that inherits from the constructor
5818 template INHERITED; turn FN into a constructor template with a matching
5819 template header. */
5821 tree
5823 {
5824 tree inner_parms
5827 tree parms
5838 }
5840 /* Called when a class template TYPE is redeclared with the indicated
5841 template PARMS, e.g.:
5843 template <class T> struct S;
5844 template <class T> struct S {}; */
5846 bool
5848 {
5849 tree tmpl;
5850 tree tmpl_parms;
5854 {
5857 }
5861 /* The type is nested in some template class. Nothing to worry
5862 about here; there are no new template parameters for the nested
5863 type. */
5867 {
5869 tmpl);
5871 }
5877 {
5887 }
5890 {
5891 tree tmpl_parm;
5892 tree parm;
5893 tree tmpl_default;
5894 tree parm_default;
5908 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5909 TEMPLATE_DECL. */
5919 {
5923 }
5926 {
5927 /* We have in [temp.param]:
5929 A template-parameter may not be given default arguments
5930 by two different declarations in the same scope. */
5935 }
5938 /* Update the previous template parameters (which are the ones
5939 that will really count) with the new default value. */
5942 /* Update the new parameters, too; they'll be used as the
5943 parameters for any members. */
5946 /* Give each template template parm in this redeclaration a
5947 DECL_CONTEXT of the template for which they are a parameter. */
5949 {
5952 }
5956 }
5958 // Cannot redeclare a class template with a different set of constraints.
5960 {
5965 }
5968 }
5970 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5971 to be used when the caller has already checked
5972 (processing_template_decl
5973 && !instantiation_dependent_expression_p (expr)
5974 && potential_constant_expression (expr))
5975 and cleared processing_template_decl. */
5977 tree
5979 {
5982 complain,
5986 }
5988 /* Simplify EXPR if it is a non-dependent expression. Returns the
5989 (possibly simplified) expression. */
5991 tree
5993 {
5997 /* If we're in a template, but EXPR isn't value dependent, simplify
5998 it. We're supposed to treat:
6000 template <typename T> void f(T[1 + 1]);
6001 template <typename T> void f(T[2]);
6003 as two declarations of the same function, for example. */
6006 {
6007 processing_template_decl_sentinel s;
6009 }
6011 }
6013 tree
6015 {
6017 }
6019 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6020 an uninstantiated expression. */
6022 tree
6024 {
6028 {
6031 else
6032 {
6033 processing_template_decl_sentinel s;
6035 }
6036 }
6038 }
6040 /* True iff T is a specialization of a variable template. */
6042 bool
6044 {
6049 }
6051 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6052 template declaration, or a TYPE_DECL for an alias declaration. */
6054 bool
6056 {
6064 }
6066 /* Return TRUE iff T is a specialization of an alias template. */
6068 bool
6070 {
6071 /* It's an alias template specialization if it's an alias and its
6072 TYPE_NAME is a specialization of a primary template. */
6078 }
6080 /* An alias template is complex from a SFINAE perspective if a template-id
6081 using that alias can be ill-formed when the expansion is not, as with
6082 the void_t template. We determine this by checking whether the
6083 expansion for the alias template uses all its template parameters. */
6085 struct uses_all_template_parms_data
6086 {
6089 };
6091 static int
6093 {
6101 }
6103 static bool
6105 {
6120 }
6122 /* Return TRUE iff T is a specialization of a complex alias template with
6123 dependent template-arguments. */
6125 bool
6127 {
6140 }
6142 /* Return the number of innermost template parameters in TMPL. */
6144 static int
6146 {
6149 }
6151 /* Return either TMPL or another template that it is equivalent to under DR
6152 1286: An alias that just changes the name of a template is equivalent to
6153 the other template. */
6155 static tree
6157 {
6160 {
6161 /* Determine if the alias is equivalent to an underlying template. */
6173 tree alias_args = INNERMOST_TEMPLATE_ARGS
6178 /* Alias is equivalent. Strip it and repeat. */
6180 }
6183 }
6185 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6186 must be a reference-to-function or a pointer-to-function type, as specified
6187 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6188 and check that the resulting function has external linkage. */
6190 static tree
6192 tsubst_flags_t complain)
6193 {
6196 linkage_kind linkage;
6211 /* [temp.arg.nontype]/1
6213 A template-argument for a non-type, non-template template-parameter
6214 shall be one of:
6215 [...]
6216 -- the address of an object or function with external [C++11: or
6217 internal] linkage. */
6220 {
6222 {
6228 else
6231 }
6233 }
6237 {
6239 {
6244 else
6248 }
6250 }
6252 accept:
6254 {
6257 else
6259 }
6264 }
6266 /* Subroutine of convert_nontype_argument.
6267 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6268 Emit an error otherwise. */
6270 static bool
6272 tsubst_flags_t complain)
6273 {
6290 {
6295 else
6297 }
6299 }
6301 /* Returns TRUE iff the address of OP is value-dependent.
6303 14.6.2.4 [temp.dep.temp]:
6304 A non-integral non-type template-argument is dependent if its type is
6305 dependent or it has either of the following forms
6306 qualified-id
6307 & qualified-id
6308 and contains a nested-name-specifier which specifies a class-name that
6309 names a dependent type.
6311 We generalize this to just say that the address of a member of a
6312 dependent class is value-dependent; the above doesn't cover the
6313 address of a static data member named with an unqualified-id. */
6315 static bool
6317 {
6318 /* We could use get_inner_reference here, but there's no need;
6319 this is only relevant for template non-type arguments, which
6320 can only be expressed as &id-expression. */
6322 {
6326 }
6329 }
6331 /* The next set of functions are used for providing helpful explanatory
6332 diagnostics for failed overload resolution. Their messages should be
6333 indented by two spaces for consistency with the messages in
6334 call.c */
6336 static int
6338 {
6340 }
6342 /* Other failure functions should call this one, to provide a single function
6343 for setting a breakpoint on. */
6345 static int
6347 {
6349 }
6351 static int
6353 {
6358 }
6360 static int
6362 {
6368 }
6370 static int
6372 {
6376 }
6378 static int
6380 {
6383 " template parameter %qD is not a parameter pack, but "
6387 }
6389 static int
6391 {
6394 " template argument %qE does not match "
6398 }
6400 static int
6402 {
6406 }
6408 static int
6410 {
6416 }
6418 static int
6420 {
6422 {
6427 else
6429 " deduced conflicting values for non-type parameter "
6431 }
6433 }
6435 static int
6437 {
6440 " variable-sized array type %qT is not "
6442 arg);
6444 }
6446 static int
6448 {
6452 arg);
6454 }
6456 static int
6458 {
6460 {
6466 else
6471 }
6473 }
6475 static int
6477 {
6479 }
6481 static int
6484 {
6486 }
6488 static int
6491 {
6497 }
6499 static int
6502 {
6505 {
6513 }
6515 }
6517 static int
6519 {
6522 " template parameters of a template template argument are "
6525 }
6527 static int
6529 {
6535 }
6537 static int
6539 {
6544 }
6546 /* Attempt to convert the non-type template parameter EXPR to the
6547 indicated TYPE. If the conversion is successful, return the
6548 converted value. If the conversion is unsuccessful, return
6549 NULL_TREE if we issued an error message, or error_mark_node if we
6550 did not. We issue error messages for out-and-out bad template
6551 parameters, but not simply because the conversion failed, since we
6552 might be just trying to do argument deduction. Both TYPE and EXPR
6553 must be non-dependent.
6555 The conversion follows the special rules described in
6556 [temp.arg.nontype], and it is much more strict than an implicit
6557 conversion.
6559 This function is called twice for each template argument (see
6560 lookup_template_class for a more accurate description of this
6561 problem). This means that we need to handle expressions which
6562 are not valid in a C++ source, but can be created from the
6563 first call (for instance, casts to perform conversions). These
6564 hacks can go away after we fix the double coercion problem. */
6566 static tree
6568 {
6569 tree expr_type;
6573 /* Detect immediately string literals as invalid non-type argument.
6574 This special-case is not needed for correctness (we would easily
6575 catch this later), but only to provide better diagnostic for this
6576 common user mistake. As suggested by DR 100, we do not mention
6577 linkage issues in the diagnostic as this is not the point. */
6578 /* FIXME we're making this OK. */
6580 {
6586 }
6588 /* Add the ADDR_EXPR now for the benefit of
6589 value_dependent_expression_p. */
6592 {
6596 }
6598 /* If we are in a template, EXPR may be non-dependent, but still
6599 have a syntactic, rather than semantic, form. For example, EXPR
6600 might be a SCOPE_REF, rather than the VAR_DECL to which the
6601 SCOPE_REF refers. Preserving the qualifying scope is necessary
6602 so that access checking can be performed when the template is
6603 instantiated -- but here we need the resolved form so that we can
6604 convert the argument. */
6616 /* If the argument is non-dependent, perform any conversions in
6617 non-dependent context as well. */
6625 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6626 to a non-type argument of "nullptr". */
6630 /* In C++11, integral or enumeration non-type template arguments can be
6631 arbitrary constant expressions. Pointer and pointer to
6632 member arguments can be general constant expressions that evaluate
6633 to a null value, but otherwise still need to be of a specific form. */
6635 {
6637 /* A PTRMEM_CST is already constant, and a valid template
6638 argument for a parameter of pointer to member type, we just want
6639 to leave it in that form rather than lower it to a
6643 {
6644 /* C++17: A template-argument for a non-type template-parameter shall
6645 be a converted constant expression (8.20) of the type of the
6646 template-parameter. */
6652 }
6654 {
6659 }
6660 }
6664 else
6667 /* HACK: Due to double coercion, we can get a
6668 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6669 which is the tree that we built on the first call (see
6670 below when coercing to reference to object or to reference to
6671 function). We just strip everything and get to the arg.
6672 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6673 for examples. */
6675 {
6681 {
6682 /* ??? Maybe we could use convert_from_reference here, but we
6683 would need to relax its constraints because the NOP_EXPR
6684 could actually change the type to something more cv-qualified,
6685 and this is not folded by convert_from_reference. */
6690 && (same_type_ignoring_top_level_qualifiers_p
6693 {
6696 }
6697 }
6698 }
6700 /* [temp.arg.nontype]/5, bullet 1
6702 For a non-type template-parameter of integral or enumeration type,
6703 integral promotions (_conv.prom_) and integral conversions
6704 (_conv.integral_) are applied. */
6706 {
6708 {
6713 }
6718 /* Notice that there are constant expressions like '4 % 0' which
6719 do not fold into integer constants. */
6722 {
6724 {
6728 else
6734 /* else cxx_constant_value complained but gave us
6735 a real constant, so go ahead. */
6737 {
6738 /* Some assemble time constant expressions like
6739 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6740 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6741 as we can emit them into .rodata initializers of
6742 variables, yet they can't fold into an INTEGER_CST at
6743 compile time. Refuse them here. */
6748 }
6749 }
6750 else
6752 }
6754 /* Avoid typedef problems. */
6757 }
6758 /* [temp.arg.nontype]/5, bullet 2
6760 For a non-type template-parameter of type pointer to object,
6761 qualification conversions (_conv.qual_) and the array-to-pointer
6762 conversion (_conv.array_) are applied. */
6764 {
6767 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6768 decay_conversion or an explicit cast. If it's a problematic cast,
6769 we'll complain about it below. */
6771 {
6776 {
6779 }
6780 }
6782 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6784 A template-argument for a non-type, non-template template-parameter
6785 shall be one of: [...]
6787 -- the name of a non-type template-parameter;
6788 -- the address of an object or function with external linkage, [...]
6789 expressed as "& id-expression" where the & is optional if the name
6790 refers to a function or array, or if the corresponding
6791 template-parameter is a reference.
6793 Here, we do not care about functions, as they are invalid anyway
6794 for a parameter of type pointer-to-object. */
6797 /* Non-type template parameters are OK. */
6798 ;
6802 {
6804 {
6807 "because %qD is a variable, not the address of "
6810 }
6812 {
6818 }
6819 /* Other values, like integer constants, might be valid
6820 non-type arguments of some other type. */
6822 }
6823 else
6824 {
6828 {
6833 }
6835 {
6841 }
6844 {
6849 }
6850 /* C++17: For a non-type template-parameter of reference or pointer
6851 type, the value of the constant expression shall not refer to (or
6852 for a pointer type, shall not be the address of):
6853 * a subobject (4.5),
6854 * a temporary object (15.2),
6855 * a string literal (5.13.5),
6856 * the result of a typeid expression (8.2.8), or
6857 * a predefined __func__ variable (11.4.1). */
6859 {
6862 decl);
6864 }
6868 {
6873 }
6875 {
6879 decl);
6881 }
6882 }
6889 }
6890 /* [temp.arg.nontype]/5, bullet 3
6892 For a non-type template-parameter of type reference to object, no
6893 conversions apply. The type referred to by the reference may be more
6894 cv-qualified than the (otherwise identical) type of the
6895 template-argument. The template-parameter is bound directly to the
6896 template-argument, which must be an lvalue. */
6898 {
6900 expr_type))
6904 {
6909 }
6912 {
6917 }
6919 /* [temp.arg.nontype]/1
6921 A template-argument for a non-type, non-template template-parameter
6922 shall be one of: [...]
6924 -- the address of an object or function with external linkage. */
6927 {
6930 {
6933 "because a reference variable does not have a constant "
6936 }
6937 }
6941 /* OK, dependent reference. We don't want to ask whether a DECL is
6943 else
6944 {
6946 {
6952 }
6954 /* DR 1155 allows internal linkage in C++11 and up. */
6957 {
6963 }
6966 }
6970 }
6971 /* [temp.arg.nontype]/5, bullet 4
6973 For a non-type template-parameter of type pointer to function, only
6974 the function-to-pointer conversion (_conv.func_) is applied. If the
6975 template-argument represents a set of overloaded functions (or a
6976 pointer to such), the matching function is selected from the set
6977 (_over.over_). */
6979 {
6980 /* If the argument is a template-id, we might not have enough
6981 context information to decay the pointer. */
6983 {
6987 }
6990 /* Null pointer values are OK in C++11. */
6996 }
6997 /* [temp.arg.nontype]/5, bullet 5
6999 For a non-type template-parameter of type reference to function, no
7000 conversions apply. If the template-argument represents a set of
7001 overloaded functions, the matching function is selected from the set
7002 (_over.over_). */
7004 {
7006 {
7008 {
7013 }
7015 }
7020 }
7021 /* [temp.arg.nontype]/5, bullet 6
7023 For a non-type template-parameter of type pointer to member function,
7024 no conversions apply. If the template-argument represents a set of
7025 overloaded member functions, the matching member function is selected
7026 from the set (_over.over_). */
7028 {
7033 /* [temp.arg.nontype] bullet 1 says the pointer to member
7034 expression must be a pointer-to-member constant. */
7039 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7040 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7043 }
7044 /* [temp.arg.nontype]/5, bullet 7
7046 For a non-type template-parameter of type pointer to data member,
7047 qualification conversions (_conv.qual_) are applied. */
7049 {
7050 /* [temp.arg.nontype] bullet 1 says the pointer to member
7051 expression must be a pointer-to-member constant. */
7059 }
7061 {
7063 {
7068 }
7070 }
7071 /* A template non-type parameter must be one of the above. */
7072 else
7075 /* Sanity check: did we actually convert the argument to the
7076 right type? */
7080 }
7082 /* Subroutine of coerce_template_template_parms, which returns 1 if
7083 PARM_PARM and ARG_PARM match using the rule for the template
7084 parameters of template template parameters. Both PARM and ARG are
7085 template parameters; the rest of the arguments are the same as for
7086 coerce_template_template_parms.
7087 */
7088 static int
7090 tree arg,
7091 tsubst_flags_t complain,
7092 tree in_decl,
7093 tree outer_args)
7094 {
7103 {
7105 /* We encounter instantiations of templates like
7106 template <template <template <class> class> class TT>
7107 class C; */
7108 {
7115 }
7116 /* Fall through. */
7121 /* Argument is a parameter pack but parameter is not. */
7126 /* The tsubst call is used to handle cases such as
7128 template <int> class C {};
7129 template <class T, template <T> class TT> class D {};
7130 D<int, C> d;
7132 i.e. the parameter list of TT depends on earlier parameters. */
7134 {
7139 }
7143 /* Argument is a parameter pack but parameter is not. */
7150 }
7153 }
7155 /* Coerce template argument list ARGLIST for use with template
7156 template-parameter TEMPL. */
7158 static tree
7160 tsubst_flags_t complain)
7161 {
7162 /* Consider an example where a template template parameter declared as
7164 template <class T, class U = std::allocator<T> > class TT
7166 The template parameter level of T and U are one level larger than
7167 of TT. To proper process the default argument of U, say when an
7168 instantiation `TT<int>' is seen, we need to build the full
7169 arguments containing {int} as the innermost level. Outer levels,
7170 available when not appearing as default template argument, can be
7171 obtained from the arguments of the enclosing template.
7173 Suppose that TT is later substituted with std::vector. The above
7174 instantiation is `TT<int, std::allocator<T> >' with TT at
7175 level 1, and T at level 2, while the template arguments at level 1
7176 becomes {std::vector} and the inner level 2 is {int}. */
7180 {
7182 /* We want arguments for the partial specialization, not arguments for
7183 the primary template. */
7185 else
7187 }
7189 {
7190 /* This is an argument of the current template, so we haven't set
7191 DECL_CONTEXT yet. */
7192 tree relevant_template_parms;
7194 /* Parameter levels that are greater than the level of the given
7195 template template parm are irrelevant. */
7202 }
7209 complain,
7212 }
7214 /* A cache of template template parameters with match-all default
7215 arguments. */
7217 static void
7219 {
7223 }
7224 static tree
7226 {
7231 }
7233 /* T is a bound template template-parameter. Copy its arguments into default
7234 arguments of the template template-parameter's template parameters. */
7236 static tree
7238 {
7261 {
7264 {
7267 }
7268 }
7272 }
7274 /* ARG is a bound potential template template-argument, and PARGS is a list
7275 of arguments for the corresponding template template-parameter. Adjust
7276 PARGS as appropriate for application to ARG's template, and if ARG is a
7277 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7278 arguments to the template template parameter. */
7280 static tree
7282 {
7286 {
7287 /* When comparing two template template-parameters in partial ordering,
7288 rewrite the one currently being used as an argument to have default
7289 arguments for all parameters. */
7295 }
7296 else
7297 {
7298 tree aparms
7303 }
7306 }
7308 /* Subroutine of unify for the case when PARM is a
7309 BOUND_TEMPLATE_TEMPLATE_PARM. */
7311 static int
7314 {
7318 /* The template template parm might be variadic and the argument
7319 not, so flatten both argument lists. */
7324 {
7325 /* In keeping with P0522R0, adjust P's template arguments
7326 to apply to A's template; then flatten it again. */
7335 /* If the P0522 adjustment eliminated a pack expansion, deduce
7336 empty packs. */
7342 }
7343 else
7344 {
7345 /* Deduce arguments T, i from TT<T> or TT<i>.
7346 We check each element of PARMVEC and ARGVEC individually
7347 rather than the whole TREE_VEC since they can have
7348 different number of elements, which is allowed under N2555. */
7352 /* Check if the parameters end in a pack, making them
7353 variadic. */
7360 /* If the template argument list of P contains a pack
7361 expansion that is not the last template argument, the
7362 entire template argument list is a non-deduced
7363 context. */
7381 DEDUCE_EXACT,
7384 }
7387 }
7389 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7390 template template parameters. Both PARM_PARMS and ARG_PARMS are
7391 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7392 or PARM_DECL.
7394 Consider the example:
7395 template <class T> class A;
7396 template<template <class U> class TT> class B;
7398 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7399 the parameters to A, and OUTER_ARGS contains A. */
7401 static int
7403 tree arg_parms,
7404 tsubst_flags_t complain,
7405 tree in_decl,
7406 tree outer_args)
7407 {
7419 {
7420 /* P0522R0: A template template-parameter P is at least as specialized as
7421 a template template-argument A if, given the following rewrite to two
7422 function templates, the function template corresponding to P is at
7423 least as specialized as the function template corresponding to A
7424 according to the partial ordering rules for function templates
7425 ([temp.func.order]). Given an invented class template X with the
7426 template parameter list of A (including default arguments):
7428 * Each of the two function templates has the same template parameters,
7429 respectively, as P or A.
7431 * Each function template has a single function parameter whose type is
7432 a specialization of X with template arguments corresponding to the
7433 template parameters from the respective function template where, for
7434 each template parameter PP in the template parameter list of the
7435 function template, a corresponding template argument AA is formed. If
7436 PP declares a parameter pack, then AA is the pack expansion
7437 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7439 If the rewrite produces an invalid type, then P is not at least as
7440 specialized as A. */
7442 /* So coerce P's args to apply to A's parms, and then deduce between A's
7443 args and the converted args. If that succeeds, A is at least as
7444 specialized as P, so they match.*/
7451 {
7457 }
7458 }
7460 /* Determine whether we have a parameter pack at the end of the
7461 template template parameter's template parameter list. */
7463 {
7470 {
7484 }
7485 }
7491 /* Check all of the template parameters except the parameter pack at
7492 the end (if any). */
7494 {
7503 outer_args))
7506 }
7509 {
7510 /* Check each of the template parameters in the template
7511 argument against the template parameter pack at the end of
7512 the template template parameter. */
7519 {
7526 outer_args))
7528 }
7529 }
7532 }
7534 /* Verifies that the deduced template arguments (in TARGS) for the
7535 template template parameters (in TPARMS) represent valid bindings,
7536 by comparing the template parameter list of each template argument
7537 to the template parameter list of its corresponding template
7538 template parameter, in accordance with DR150. This
7539 routine can only be called after all template arguments have been
7540 deduced. It will return TRUE if all of the template template
7541 parameter bindings are okay, FALSE otherwise. */
7542 bool
7544 {
7548 /* We're dealing with template parms in this process. */
7554 {
7559 {
7564 {
7565 /* Look inside the argument pack. */
7568 }
7571 {
7575 /* Extract the next argument from the argument
7576 pack. */
7580 /* Look at the pattern of the pack expansion. */
7583 /* Extract the template parameters from the template
7584 argument. */
7590 /* Verify that we can coerce the template template
7591 parameters from the template argument to the template
7592 parameter. This requires an exact match. */
7594 && !coerce_template_template_parms
7596 targ_parms,
7597 tf_none,
7598 tparm,
7599 targs))
7600 {
7603 }
7604 }
7605 }
7606 }
7608 out:
7612 }
7614 /* Since type attributes aren't mangled, we need to strip them from
7615 template type arguments. */
7617 static tree
7619 {
7629 }
7631 /* And from inside dependent non-type arguments like sizeof(Type). */
7633 static tree
7635 {
7645 }
7647 // A template declaration can be substituted for a constrained
7648 // template template parameter only when the argument is more
7649 // constrained than the parameter.
7650 static bool
7652 {
7655 /* For now, allow constrained template template arguments
7656 and unconstrained template template parameters. */
7662 // If the template parameter is constrained, we need to rewrite its
7663 // constraints in terms of the ARG's template parameters. This ensures
7664 // that all of the template parameter types will have the same depth.
7665 //
7666 // Note that this is only valid when coerce_template_template_parm is
7667 // true for the innermost template parameters of PARM and ARG. In other
7668 // words, because coercion is successful, this conversion will be valid.
7670 {
7677 }
7680 }
7682 // Convert a placeholder argument into a binding to the original
7683 // parameter. The original parameter is saved as the TREE_TYPE of
7684 // ARG.
7687 {
7690 }
7692 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7693 because one of them is dependent. But we need to represent the
7694 conversion for the benefit of cp_tree_equal. */
7696 static tree
7698 {
7699 /* Auto parms get no conversion. */
7702 /* We don't need or want to add this conversion now if we're going to use the
7703 argument for deduction. */
7715 }
7717 /* Convert the indicated template ARG as necessary to match the
7718 indicated template PARM. Returns the converted ARG, or
7719 error_mark_node if the conversion was unsuccessful. Error and
7720 warning messages are issued under control of COMPLAIN. This
7721 conversion is for the Ith parameter in the parameter list. ARGS is
7722 the full set of template arguments deduced so far. */
7724 static tree
7726 tree arg,
7727 tree args,
7728 tsubst_flags_t complain,
7730 tree in_decl)
7731 {
7732 tree orig_arg;
7733 tree val;
7739 /* Trivially convert placeholders. */
7748 {
7749 /* The template argument was the name of some
7750 member function. That's usually
7751 invalid, but static members are OK. In any
7752 case, grab the underlying fields/functions
7753 and issue an error later if required. */
7756 }
7764 /* When determining whether an argument pack expansion is a template,
7765 look at the pattern. */
7769 /* Deal with an injected-class-name used as a template template arg. */
7771 {
7774 {
7784 }
7785 }
7787 is_tmpl_type =
7803 {
7805 {
7809 }
7812 "to refer to a type member of a template parameter, "
7817 typename_type,
7818 complain);
7821 }
7823 {
7825 {
7827 {
7839 else
7842 }
7843 }
7845 }
7847 {
7849 {
7856 else
7859 }
7861 }
7864 /* We already did the appropriate conversion when packing args. */
7867 {
7869 {
7871 /* The number of argument required is not known yet.
7872 Just accept it for now. */
7874 else
7875 {
7877 tree argparm;
7879 /* Strip alias templates that are equivalent to another
7880 template. */
7886 args))
7887 {
7890 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7891 TEMPLATE_DECL. */
7893 {
7898 }
7899 }
7900 else
7901 {
7903 {
7910 }
7913 }
7915 // Check that the constraints are compatible before allowing the
7916 // substitution.
7919 {
7921 {
7927 }
7929 }
7930 }
7931 }
7932 else
7934 /* We only form one instance of each template specialization.
7935 Therefore, if we use a non-canonical variant (i.e., a
7936 typedef), any future messages referring to the type will use
7937 the typedef, which is confusing if those future uses do not
7938 themselves also use the typedef. */
7941 }
7942 else
7943 {
7947 {
7951 }
7952 else
7960 /* We used to call digest_init here. However, digest_init
7961 will report errors, which we don't want when complain
7962 is zero. More importantly, digest_init will try too
7963 hard to convert things: for example, `0' should not be
7964 converted to pointer type at this point according to
7965 the standard. Accepting this is not merely an
7966 extension, since deciding whether or not these
7967 conversions can occur is part of determining which
7968 function template to call, or whether a given explicit
7969 argument specification is valid. */
7971 else
7972 {
7975 }
7985 {
7986 /* Reject template arguments that are references to built-in
7987 functions with no library fallbacks. */
7996 }
7999 {
8000 /* Strip typedefs from the SCOPE_REF. */
8003 complain);
8006 }
8007 }
8010 }
8012 /* Coerces the remaining template arguments in INNER_ARGS (from
8013 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8014 Returns the coerced argument pack. PARM_IDX is the position of this
8015 parameter in the template parameter list. ARGS is the original
8016 template argument list. */
8017 static tree
8020 tree args,
8021 tree inner_args,
8023 tree new_args,
8025 tree in_decl,
8026 tsubst_flags_t complain)
8027 {
8030 tree packed_args;
8031 tree argument_pack;
8038 {
8039 /* When the template parameter is a non-type template parameter pack
8040 or template template parameter pack whose type or template
8041 parameters use parameter packs, we know exactly how many arguments
8042 we are looking for. Build a vector of the instantiated decls for
8043 these template parameters in PACKED_PARMS. */
8044 /* We can't use make_pack_expansion here because it would interpret a
8045 _DECL as a use rather than a declaration. */
8059 /* If we're doing a partial instantiation of a member template,
8060 verify that all of the types used for the non-type
8061 template parameter pack are, in fact, valid for non-type
8062 template parameters. */
8065 {
8068 {
8072 }
8073 /* We don't know how many args we have yet, just
8074 use the unconverted ones for now. */
8076 }
8079 }
8080 /* Check if we have a placeholder pack, which indicates we're
8081 in the context of a introduction list. In that case we want
8082 to match this pack to the single placeholder. */
8086 {
8089 }
8090 else
8093 /* Convert the remaining arguments, which will be a part of the
8094 parameter pack "parm". */
8097 {
8103 {
8104 /* Once we've packed as many args as we have types, stop. */
8108 /* We don't know how many args we have yet, just
8109 use the unconverted ones for now. */
8111 else
8113 }
8116 {
8119 }
8120 else
8123 in_decl);
8127 }
8131 {
8136 }
8141 else
8142 {
8145 }
8152 }
8154 /* Returns the number of pack expansions in the template argument vector
8155 ARGS. */
8157 static int
8159 {
8164 {
8168 }
8170 }
8172 /* Convert all template arguments to their appropriate types, and
8173 return a vector containing the innermost resulting template
8174 arguments. If any error occurs, return error_mark_node. Error and
8175 warning messages are issued under control of COMPLAIN.
8177 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8178 for arguments not specified in ARGS. Otherwise, if
8179 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8180 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8181 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8182 ARGS. */
8184 static tree
8186 tree args,
8187 tree in_decl,
8188 tsubst_flags_t complain,
8191 {
8193 tree orig_inner_args;
8194 tree inner_args;
8195 tree new_args;
8196 tree new_inner_args;
8200 /* When used as a boolean value, indicates whether this is a
8201 variadic template parameter list. Since it's an int, we can also
8202 subtract it from nparms to get the number of non-variadic
8203 parameters. */
8208 /* Likewise for parameters with default arguments. */
8216 /* Determine if there are any parameter packs or default arguments. */
8218 {
8226 }
8229 /* If there are no parameters that follow a parameter pack, we need to
8230 expand any argument packs so that we can deduce a parameter pack from
8231 some non-packed args followed by an argument pack, as in variadic85.C.
8232 If there are such parameters, we need to leave argument packs intact
8233 so the arguments are assigned properly. This can happen when dealing
8234 with a nested class inside a partial specialization of a class
8235 template, as in variadic92.C, or when deducing a template parameter pack
8236 from a sub-declarator, as in variadic114.C. */
8240 /* Count any pack expansion args. */
8246 && require_all_args
8247 && !variadic_args_p
8248 && (!use_default_args
8251 {
8253 {
8255 {
8259 }
8260 else
8267 }
8270 }
8271 /* We can't pass a pack expansion to a non-pack parameter of an alias
8272 template (DR 1430). */
8276 && variadic_args_p
8278 {
8280 {
8282 {
8288 {
8291 "pack expansion argument for non-pack parameter "
8293 else
8295 "pack expansion argument for non-pack parameter "
8299 }
8300 }
8302 found:;
8303 }
8305 }
8307 /* We need to evaluate the template arguments, even though this
8308 template-id may be nested within a "sizeof". */
8317 {
8318 tree arg;
8319 tree parm;
8321 /* Get the Ith template parameter. */
8325 {
8328 }
8330 /* Calculate the next argument. */
8333 else
8338 {
8339 /* Some arguments will be placed in the
8340 template parameter pack PARM. */
8347 {
8348 /* We don't know how many args we have yet, just use the
8349 unconverted (and still packed) ones for now. */
8353 }
8357 /* Store this argument. */
8359 {
8360 lost++;
8361 /* We are done with all of the arguments. */
8363 }
8364 else
8365 {
8368 }
8371 }
8373 {
8375 {
8376 /* "If every valid specialization of a variadic template
8377 requires an empty template parameter pack, the template is
8378 ill-formed, no diagnostic required." So check that the
8379 pattern works with this parameter. */
8384 in_decl);
8386 {
8391 }
8393 /* Recover from missing typename. */
8397 /* We don't know how many args we have yet, just
8398 use the unconverted ones for now. */
8402 }
8403 }
8405 {
8406 /* There must be a default arg in this case. */
8409 /* The position of the first default template argument,
8410 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8411 Record that. */
8415 }
8416 else
8420 {
8423 }
8425 /* This only occurs if there was an error in the template
8426 parameter list itself (which we would already have
8427 reported) that we are trying to recover from, e.g., a class
8428 template with a parameter list such as
8429 template<typename..., typename>. */
8431 else
8437 lost++;
8439 }
8444 {
8446 {
8451 }
8453 }
8463 }
8465 /* Convert all template arguments to their appropriate types, and
8466 return a vector containing the innermost resulting template
8467 arguments. If any error occurs, return error_mark_node. Error and
8468 warning messages are not issued.
8470 Note that no function argument deduction is performed, and default
8471 arguments are used to fill in unspecified arguments. */
8472 tree
8474 {
8476 }
8478 /* Convert all template arguments to their appropriate type, and
8479 instantiate default arguments as needed. This returns a vector
8480 containing the innermost resulting template arguments, or
8481 error_mark_node if unsuccessful. */
8482 tree
8484 tsubst_flags_t complain)
8485 {
8487 }
8489 /* Like coerce_template_parms. If PARMS represents all template
8490 parameters levels, this function returns a vector of vectors
8491 representing all the resulting argument levels. Note that in this
8492 case, only the innermost arguments are coerced because the
8493 outermost ones are supposed to have been coerced already.
8495 Otherwise, if PARMS represents only (the innermost) vector of
8496 parameters, this function returns a vector containing just the
8497 innermost resulting arguments. */
8499 static tree
8501 tree args,
8502 tree in_decl,
8503 tsubst_flags_t complain,
8506 {
8509 tree coerced_args;
8512 {
8514 tree level;
8520 {
8521 tree l;
8525 require_all_args,
8526 use_default_args);
8527 else
8534 }
8535 }
8536 else
8539 require_all_args,
8540 use_default_args);
8542 }
8544 /* Returns 1 if template args OT and NT are equivalent. */
8546 int
8548 {
8557 /* For member templates */
8566 {
8583 }
8587 {
8590 /* Don't treat an alias template specialization with dependent
8591 arguments as equivalent to its underlying type when used as a
8592 template argument; we need them to be distinct so that we
8593 substitute into the specialization arguments at instantiation
8594 time. And aliases can't be equivalent without being ==, so
8595 we don't need to look any deeper.
8597 During partial ordering, however, we need to treat them normally so
8598 that we can order uses of the same alias with different
8599 cv-qualification (79960). */
8603 else
8605 }
8608 else
8609 {
8610 /* Try to treat a template non-type argument that has been converted
8611 to the parameter type as equivalent to one that hasn't yet. */
8624 }
8625 }
8627 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8628 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8629 NEWARG_PTR with the offending arguments if they are non-NULL. */
8631 int
8635 {
8648 {
8653 {
8659 }
8660 }
8662 }
8666 {
8668 }
8670 static void
8672 {
8682 /* We are called both from instantiate_decl, where we've already had a
8683 tinst_level pushed, and instantiate_template, where we haven't.
8684 Compensate. */
8695 else
8704 }
8707 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8708 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8709 documentation for TEMPLATE_ID_EXPR. */
8711 tree
8713 {
8714 tree type;
8722 {
8725 }
8728 {
8730 unknown_type_node,
8732 arglist);
8734 }
8741 }
8743 /* Within the scope of a template class S<T>, the name S gets bound
8744 (in build_self_reference) to a TYPE_DECL for the class, not a
8745 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8746 or one of its enclosing classes, and that type is a template,
8747 return the associated TEMPLATE_DECL. Otherwise, the original
8748 DECL is returned.
8750 Also handle the case when DECL is a TREE_LIST of ambiguous
8751 injected-class-names from different bases. */
8753 tree
8755 {
8759 /* DR 176: A lookup that finds an injected-class-name (10.2
8760 [class.member.lookup]) can result in an ambiguity in certain cases
8761 (for example, if it is found in more than one base class). If all of
8762 the injected-class-names that are found refer to specializations of
8763 the same class template, and if the name is followed by a
8764 template-argument-list, the reference refers to the class template
8765 itself and not a specialization thereof, and is not ambiguous. */
8767 {
8770 {
8776 }
8779 else
8781 }
8787 }
8789 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8790 parameters, find the desired type.
8792 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8794 IN_DECL, if non-NULL, is the template declaration we are trying to
8795 instantiate.
8797 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8798 the class we are looking up.
8800 Issue error and warning messages under control of COMPLAIN.
8802 If the template class is really a local class in a template
8803 function, then the FUNCTION_CONTEXT is the function in which it is
8804 being instantiated.
8806 ??? Note that this function is currently called *twice* for each
8807 template-id: the first time from the parser, while creating the
8808 incomplete type (finish_template_type), and the second type during the
8809 real instantiation (instantiate_template_class). This is surely something
8810 that we want to avoid. It also causes some problems with argument
8811 coercion (see convert_nontype_argument for more information on this). */
8813 static tree
8816 {
8818 tree t;
8821 spec_entry elt;
8822 hashval_t hash;
8825 {
8829 else
8830 {
8837 }
8840 }
8842 {
8845 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8846 an implicit typename for the second A. Deal with it. */
8851 {
8854 }
8855 }
8858 {
8861 }
8863 {
8867 }
8869 {
8872 }
8874 /* Issue an error message if we didn't find a template. */
8876 {
8880 }
8883 /* Make sure it's a user visible template, if it was named by
8884 the user. */
8887 {
8889 {
8893 }
8895 }
8899 /* An alias that just changes the name of a template is equivalent to the
8900 other template, so if any of the arguments are pack expansions, strip
8901 the alias to avoid problems with a pack expansion passed to a non-pack
8902 alias template parameter (DR 1430). */
8907 {
8908 tree parm;
8917 }
8918 else
8919 {
8921 tree gen_tmpl;
8922 tree type_decl;
8930 /* An error occurred while building the template TEMPL, and a
8931 diagnostic has most certainly been emitted for that
8932 already. Let's propagate that error. */
8941 {
8942 /* We've been given an incomplete set of template arguments.
8943 For example, given:
8945 template <class T> struct S1 {
8946 template <class U> struct S2 {};
8947 template <class U> struct S2<U*> {};
8948 };
8950 we will be called with an ARGLIST of `U*', but the
8951 TEMPLATE will be `template <class T> template
8952 <class U> struct S1<T>::S2'. We must fill in the missing
8953 arguments. */
8957 }
8959 /* Now we should have enough arguments. */
8962 /* From here on, we're only interested in the most general
8963 template. */
8965 /* Calculate the BOUND_ARGS. These will be the args that are
8966 actually tsubst'd into the definition to create the
8967 instantiation. */
8969 complain,
8974 /* We were unable to bind the arguments. */
8977 /* In the scope of a template class, explicit references to the
8978 template class refer to the type of the template, not any
8979 instantiation of it. For example, in:
8981 template <class T> class C { void f(C<T>); }
8983 the `C<T>' is just the same as `C'. Outside of the
8984 class, however, such a reference is an instantiation. */
8988 {
8993 }
8995 /* If we already have this specialization, return it. */
9005 /* If the the template's constraints are not satisfied,
9006 then we cannot form a valid type.
9008 Note that the check is deferred until after the hash
9009 lookup. This prevents redundant checks on previously
9010 instantiated specializations. */
9012 {
9014 {
9017 }
9019 }
9023 /* If the deduced arguments are invalid, then the binding
9024 failed. */
9028 complain))
9035 {
9040 }
9050 /* Create the type. */
9052 {
9053 /* The user referred to a specialization of an alias
9054 template represented by GEN_TMPL.
9056 [temp.alias]/2 says:
9058 When a template-id refers to the specialization of an
9059 alias template, it is equivalent to the associated
9060 type obtained by substitution of its
9061 template-arguments for the template-parameters in the
9062 type-id of the alias template. */
9065 /* Note that the call above (by indirectly calling
9066 register_specialization in tsubst_decl) registers the
9067 TYPE_DECL representing the specialization of the alias
9068 template. So next time someone substitutes ARGLIST for
9069 the template parms into the alias template (GEN_TMPL),
9070 she'll get that TYPE_DECL back. */
9074 }
9076 {
9078 {
9089 }
9090 else
9091 {
9092 /* We don't want to call start_enum for this type, since
9093 the values for the enumeration constants may involve
9094 template parameters. And, no one should be interested
9095 in the enumeration constants for such a type. */
9098 }
9102 }
9104 {
9105 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9106 instantiated here. */
9114 /* A local class. Make sure the decl gets registered properly. */
9119 /* This instantiation is another name for the primary
9120 template type. Set the TYPE_CANONICAL field
9121 appropriately. */
9124 /* Some of the template arguments require structural
9125 equality testing, so this template class requires
9126 structural equality testing. */
9128 }
9129 else
9132 /* If we called start_enum or pushtag above, this information
9133 will already be set up. */
9135 {
9142 }
9143 else
9147 {
9153 {
9156 }
9157 }
9161 {
9165 {
9166 tree attributes
9174 }
9175 }
9177 /* Let's consider the explicit specialization of a member
9178 of a class template specialization that is implicitly instantiated,
9179 e.g.:
9180 template<class T>
9181 struct S
9182 {
9183 template<class U> struct M {}; //#0
9184 };
9186 template<>
9187 template<>
9188 struct S<int>::M<char> //#1
9189 {
9190 int i;
9191 };
9192 [temp.expl.spec]/4 says this is valid.
9194 In this case, when we write:
9195 S<int>::M<char> m;
9197 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9198 the one of #0.
9200 When we encounter #1, we want to store the partial instantiation
9201 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9203 For all cases other than this "explicit specialization of member of a
9204 class template", we just want to store the most general template into
9205 the CLASSTYPE_TI_TEMPLATE of M.
9207 This case of "explicit specialization of member of a class template"
9208 only happens when:
9209 1/ the enclosing class is an instantiation of, and therefore not
9210 the same as, the context of the most general template, and
9211 2/ we aren't looking at the partial instantiation itself, i.e.
9212 the innermost arguments are not the same as the innermost parms of
9213 the most general template.
9215 So it's only when 1/ and 2/ happens that we want to use the partial
9216 instantiation of the member template in lieu of its most general
9217 template. */
9221 /* the enclosing class must be an instantiation... */
9224 {
9228 tree partial_inst_args =
9235 use_partial_inst_tmpl =
9236 /*...and we must not be looking at the partial instantiation
9237 itself. */
9239 partial_inst_args);
9240 }
9243 /* This case is easy; there are no member templates involved. */
9245 else
9246 {
9247 /* This is a full instantiation of a member template. Find
9248 the partial instantiation of which this is an instance. */
9250 /* Temporarily reduce by one the number of levels in the ARGLIST
9251 so as to avoid comparing the last set of arguments. */
9255 /* FOUND is either a proper class type, or an alias
9256 template specialization. In the later case, it's a
9257 TYPE_DECL, resulting from the substituting of arguments
9258 for parameters in the TYPE_DECL of the alias template
9259 done earlier. So be careful while getting the template
9260 of FOUND. */
9262 ? found
9266 }
9268 // Build template info for the new specialization.
9277 /* Note this use of the partial instantiation so we can check it
9278 later in maybe_process_partial_specialization. */
9285 /* Now that the type has been registered on the instantiations
9286 list, we set up the enumerators. Because the enumeration
9287 constants may involve the enumeration type itself, we make
9288 sure to register the type first, and then create the
9289 constants. That way, doing tsubst_expr for the enumeration
9290 constants won't result in recursive calls here; we'll find
9291 the instantiation and exit above. */
9295 /* If the type makes use of template parameters, the
9296 code that generates debugging information will crash. */
9299 /* Possibly limit visibility based on template args. */
9306 }
9307 }
9309 /* Wrapper for lookup_template_class_1. */
9311 tree
9314 {
9315 tree ret;
9321 }
9323 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9325 tree
9327 {
9328 /* The type of the expression is NULL_TREE since the template-id could refer
9329 to an explicit or partial specialization. */
9332 /* Except that concepts are always bool. */
9335 }
9337 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9339 tree
9341 {
9345 /* We never want to return a VAR_DECL for a variable concept, since they
9346 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9361 {
9363 {
9366 }
9368 }
9370 /* If a template-id refers to a specialization of a variable
9371 concept, then the expression is true if and only if the
9372 concept's constraints are satisfied by the given template
9373 arguments.
9375 NOTE: This is an extension of Concepts Lite TS that
9376 allows constraints to be used in expressions. */
9378 {
9381 }
9384 }
9386 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9387 TARGS template args, and instantiate it if it's not dependent. */
9389 tree
9391 tsubst_flags_t complain)
9392 {
9395 {
9398 }
9401 }
9403 \f
9404 struct pair_fn_data
9405 {
9406 tree_fn_t fn;
9407 tree_fn_t any_fn;
9409 /* True when we should also visit template parameters that occur in
9410 non-deduced contexts. */
9413 };
9415 /* Called from for_each_template_parm via walk_tree. */
9417 static tree
9419 {
9426 #define WALK_SUBTREE(NODE) \
9427 do \
9428 { \
9429 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9430 pfd->include_nondeduced_p, \
9431 pfd->any_fn); \
9432 if (result) goto out; \
9433 } \
9434 while (0)
9444 {
9448 /* Fall through. */
9454 else
9464 /* Since we're not going to walk subtrees, we have to do this
9465 explicitly here. */
9467 /* Fall through. */
9470 /* Check the return type. */
9473 /* Check the parameter types. Since default arguments are not
9474 instantiated until they are needed, the TYPE_ARG_TYPES may
9475 contain expressions that involve template parameters. But,
9476 no-one should be looking at them yet. And, once they're
9477 instantiated, they don't contain template parameters, so
9478 there's no point in looking at them then, either. */
9479 {
9480 tree parm;
9485 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9486 want walk_tree walking into them itself. */
9488 }
9491 {
9495 }
9512 /* Fall through. */
9524 /* Record template parameters such as `T' inside `TT<T>'. */
9526 /* Fall through. */
9538 /* A template template parameter is encountered. */
9542 /* Already substituted template template parameter */
9547 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9548 partial instantiation. */
9560 /* If there's no type, then this thing must be some expression
9561 involving template parameters. */
9583 }
9585 #undef WALK_SUBTREE
9587 /* We didn't find any template parameters we liked. */
9588 out:
9590 }
9592 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9593 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9594 call FN with the parameter and the DATA.
9595 If FN returns nonzero, the iteration is terminated, and
9596 for_each_template_parm returns 1. Otherwise, the iteration
9597 continues. If FN never returns a nonzero value, the value
9598 returned by for_each_template_parm is 0. If FN is NULL, it is
9599 considered to be the function which always returns 1.
9601 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9602 parameters that occur in non-deduced contexts. When false, only
9603 visits those template parameters that can be deduced. */
9605 static tree
9609 tree_fn_t any_fn)
9610 {
9612 tree result;
9614 /* Set up. */
9620 /* Walk the tree. (Conceptually, we would like to walk without
9621 duplicates, but for_each_template_parm_r recursively calls
9622 for_each_template_parm, so we would need to reorganize a fair
9623 bit to use walk_tree_without_duplicates, so we keep our own
9624 visited list.) */
9627 else
9630 for_each_template_parm_r,
9634 /* Clean up. */
9636 {
9639 }
9642 }
9644 /* Returns true if T depends on any template parameter. */
9646 int
9648 {
9678 else
9679 {
9682 }
9687 }
9689 /* Returns true iff current_function_decl is an incompletely instantiated
9690 template. Useful instead of processing_template_decl because the latter
9691 is set to 0 during instantiate_non_dependent_expr. */
9693 bool
9695 {
9704 }
9706 /* Returns true if T depends on any template parameter with level LEVEL. */
9708 bool
9710 {
9713 }
9715 /* Returns true if the signature of DECL depends on any template parameter from
9716 its enclosing class. */
9718 bool
9720 {
9730 template_parm_outer_level,
9740 }
9742 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9743 ill-formed translation unit, i.e. a variable or function that isn't
9744 usable in a constant expression. */
9748 {
9753 }
9755 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9756 neglectable and instantiated from within an erroneous instantiation. */
9758 static bool
9760 {
9771 }
9779 /* We're starting to instantiate D; record the template instantiation context
9780 for diagnostics and to restore it later. */
9782 bool
9784 {
9786 }
9788 /* We're starting to instantiate D; record the template instantiation context
9789 at LOC for diagnostics and to restore it later. */
9791 bool
9793 {
9797 {
9798 /* Tell error.c not to try to instantiate any templates. */
9801 "template instantiation depth exceeds maximum of %d"
9803 max_tinst_depth);
9805 }
9807 /* If the current instantiation caused problems, don't let it instantiate
9808 anything else. Do allow deduction substitution and decls usable in
9809 constant expressions. */
9813 /* When not -quiet, dump template instantiations other than functions, since
9814 announce_function will take care of those. */
9833 }
9835 /* We're done instantiating this template; return to the instantiation
9836 context. */
9838 void
9840 {
9841 /* Restore the filename and line number stashed away when we started
9842 this instantiation. */
9846 }
9848 /* We're instantiating a deferred template; restore the template
9849 instantiation context in which the instantiation was requested, which
9850 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9852 static tree
9854 {
9866 }
9868 /* Returns the TINST_LEVEL which gives the original instantiation
9869 context. */
9873 {
9879 }
9881 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9882 vector of template arguments, as for tsubst.
9884 Returns an appropriate tsubst'd friend declaration. */
9886 static tree
9888 {
9889 tree new_friend;
9894 /* This was a friend declared with an explicit template
9895 argument list, e.g.:
9897 friend void f<>(T);
9899 to indicate that f was a template instantiation, not a new
9900 function declaration. Now, we have to figure out what
9901 instantiation of what template. */
9902 {
9904 tree new_args;
9905 tree tmpl;
9908 /* Friend functions are looked up in the containing namespace scope.
9909 We must enter that scope, to avoid finding member functions of the
9910 current class with same name. */
9925 tsk_none);
9927 }
9931 /* The NEW_FRIEND will look like an instantiation, to the
9932 compiler, but is not an instantiation from the point of view of
9933 the language. For example, we might have had:
9935 template <class T> struct S {
9936 template <class U> friend void f(T, U);
9937 };
9939 Then, in S<int>, template <class U> void f(int, U) is not an
9940 instantiation of anything. */
9946 {
9950 }
9952 /* The mangled name for the NEW_FRIEND is incorrect. The function
9953 is not a template instantiation and should not be mangled like
9954 one. Therefore, we forget the mangling here; we'll recompute it
9955 later if we need it. */
9957 {
9960 }
9963 {
9964 tree old_decl;
9965 tree new_friend_template_info;
9966 tree new_friend_result_template_info;
9967 tree ns;
9970 /* We must save some information from NEW_FRIEND before calling
9971 duplicate decls since that function will free NEW_FRIEND if
9972 possible. */
9974 new_friend_is_defn =
9979 {
9980 /* This declaration is a `primary' template. */
9983 new_friend_result_template_info
9985 }
9986 else
9989 /* Inside pushdecl_namespace_level, we will push into the
9990 current namespace. However, the friend function should go
9991 into the namespace of the template. */
10001 {
10002 /* This new friend declaration matched an existing
10003 declaration. For example, given:
10005 template <class T> void f(T);
10006 template <class U> class C {
10007 template <class T> friend void f(T) {}
10008 };
10010 the friend declaration actually provides the definition
10011 of `f', once C has been instantiated for some type. So,
10012 old_decl will be the out-of-class template declaration,
10013 while new_friend is the in-class definition.
10015 But, if `f' was called before this point, the
10016 instantiation of `f' will have DECL_TI_ARGS corresponding
10017 to `T' but not to `U', references to which might appear
10018 in the definition of `f'. Previously, the most general
10019 template for an instantiation of `f' was the out-of-class
10020 version; now it is the in-class version. Therefore, we
10021 run through all specialization of `f', adding to their
10022 DECL_TI_ARGS appropriately. In particular, they need a
10023 new set of outer arguments, corresponding to the
10024 arguments for this class instantiation.
10026 The same situation can arise with something like this:
10028 friend void f(int);
10029 template <class T> class C {
10030 friend void f(T) {}
10031 };
10033 when `C<int>' is instantiated. Now, `f(int)' is defined
10034 in the class. */
10037 /* On the other hand, if the in-class declaration does
10038 *not* provide a definition, then we don't want to alter
10039 existing definitions. We can just leave everything
10040 alone. */
10041 ;
10042 else
10043 {
10047 /* Overwrite whatever template info was there before, if
10048 any, with the new template information pertaining to
10049 the declaration. */
10053 {
10054 /* We should have called reregister_specialization in
10055 duplicate_decls. */
10060 /* Instantiate it if the global has already been used. */
10064 }
10065 else
10066 {
10067 tree t;
10069 /* Indicate that the old function template is a partial
10070 instantiation. */
10078 /* Reassign any specializations already in the hash table
10079 to the new more general template, and add the
10080 additional template args. */
10084 {
10086 spec_entry elt;
10098 register_specialization
10101 }
10103 }
10104 }
10106 /* The information from NEW_FRIEND has been merged into OLD_DECL
10107 by duplicate_decls. */
10109 }
10110 }
10111 else
10112 {
10116 /* In the code
10117 template <class T> class C {
10118 template <class U> friend void C1<U>::f (); // case 1
10119 friend void C2<T>::f (); // case 2
10120 };
10121 we only need to make sure CONTEXT is a complete type for
10122 case 2. To distinguish between the two cases, we note that
10123 CONTEXT of case 1 remains dependent type after tsubst while
10124 this isn't true for case 2. */
10134 {
10136 /* do_friend adds the TEMPLATE_DECL for any member friend
10137 template even if it isn't a member template, i.e.
10138 template <class T> friend A<T>::f();
10139 Look through it in that case. */
10143 /* Check to see that the declaration is really present, and,
10144 possibly obtain an improved declaration. */
10149 }
10150 }
10153 }
10155 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10156 template arguments, as for tsubst.
10158 Returns an appropriate tsubst'd friend type or error_mark_node on
10159 failure. */
10161 static tree
10163 {
10164 tree tmpl;
10167 {
10170 }
10175 else
10183 {
10184 /* The friend template has already been declared. Just
10185 check to see that the declarations match, and install any new
10186 default parameters. We must tsubst the default parameters,
10187 of course. We only need the innermost template parameters
10188 because that is all that redeclare_class_template will look
10189 at. */
10192 {
10200 }
10201 }
10202 else
10203 {
10204 /* The friend template has not already been declared. In this
10205 case, the instantiation of the template class will cause the
10206 injection of this template into the namespace scope. */
10210 {
10211 /* The new TMPL is not an instantiation of anything, so we
10212 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10213 for the new type because that is supposed to be the
10214 corresponding template decl, i.e., TMPL. */
10221 /* It is hidden. */
10226 /* Inject this template into the enclosing namspace scope. */
10228 }
10229 }
10233 else
10237 }
10239 /* Returns zero if TYPE cannot be completed later due to circularity.
10240 Otherwise returns one. */
10242 static int
10244 {
10254 else
10256 }
10261 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10262 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10264 static tree
10267 {
10276 {
10283 clauses
10287 else
10289 }
10290 /* If the first attribute argument is an identifier, don't
10291 pass it through tsubst. Attributes like mode, format,
10292 cleanup and several target specific attributes expect it
10293 unmodified. */
10295 {
10296 tree chain
10301 }
10303 {
10304 /* An attribute pack expansion. */
10313 {
10317 }
10319 }
10320 else
10327 }
10329 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10330 unchanged or a new TREE_LIST chain. */
10332 static tree
10335 {
10340 {
10344 }
10348 {
10351 {
10354 {
10360 }
10361 }
10363 }
10366 }
10368 /* Apply any attributes which had to be deferred until instantiation
10369 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10370 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10372 static void
10375 {
10377 tree t;
10384 {
10388 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10389 to our attributes parameter. */
10391 }
10392 else
10393 {
10395 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10396 lookup_template_class_1, and should be preserved. */
10400 }
10404 {
10408 }
10412 {
10417 {
10420 {
10426 }
10427 else
10429 }
10432 }
10433 }
10435 /* Perform (or defer) access check for typedefs that were referenced
10436 from within the template TMPL code.
10437 This is a subroutine of instantiate_decl and instantiate_class_template.
10438 TMPL is the template to consider and TARGS is the list of arguments of
10439 that template. */
10441 static void
10443 {
10444 location_t saved_location;
10455 {
10467 /* Make access check error messages point to the location
10468 of the use of the typedef. */
10472 tf_warning_or_error);
10473 }
10475 }
10477 static tree
10479 {
10481 tree typedecl;
10482 tree pbinfo;
10483 tree base_list;
10485 tree fn_context;
10494 /* Figure out which template is being instantiated. */
10498 /* Mark the type as in the process of being defined. */
10501 /* Determine what specialization of the original template to
10502 instantiate. */
10507 {
10508 /* This TYPE is actually an instantiation of a partial
10509 specialization. We replace the innermost set of ARGS with
10510 the arguments appropriate for substitution. For example,
10511 given:
10513 template <class T> struct S {};
10514 template <class T> struct S<T*> {};
10516 and supposing that we are instantiating S<int*>, ARGS will
10517 presently be {int*} -- but we need {int}. */
10520 }
10521 else
10522 {
10525 }
10527 /* If the template we're instantiating is incomplete, then clearly
10528 there's nothing we can do. */
10530 {
10531 /* We can try again later. */
10534 }
10536 /* If we've recursively instantiated too many templates, stop. */
10540 /* We may be in the middle of deferred access check. Disable
10541 it now. */
10548 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10553 else
10554 {
10557 }
10558 /* Use #pragma pack from the template context. */
10564 /* Set the input location to the most specialized template definition.
10565 This is needed if tsubsting causes an error. */
10577 {
10580 /* Adjust visibility for template arguments. */
10582 }
10588 /* We should never instantiate a nested class before its enclosing
10589 class; we need to look up the nested class by name before we can
10590 instantiate it, and that lookup should instantiate the enclosing
10591 class. */
10597 {
10598 tree pbase_binfo;
10599 tree pushed_scope;
10602 /* We must enter the scope containing the type, as that is where
10603 the accessibility of types named in dependent bases are
10604 looked up from. */
10607 /* Substitute into each of the bases to determine the actual
10608 basetypes. */
10610 {
10611 tree base;
10617 {
10618 expanded_bases =
10625 }
10628 {
10630 /* Extract the already-expanded base class. */
10632 else
10633 /* Substitute to figure out the base class. */
10635 NULL_TREE);
10643 }
10644 }
10646 /* The list is now in reverse order; correct that. */
10651 }
10652 /* Now call xref_basetypes to set up all the base-class
10653 information. */
10661 /* Now that our base classes are set up, enter the scope of the
10662 class, so that name lookups into base classes, etc. will work
10663 correctly. This is precisely analogous to what we do in
10664 begin_class_definition when defining an ordinary non-template
10665 class, except we also need to push the enclosing classes. */
10668 /* Now members are processed in the order of declaration. */
10671 {
10675 {
10677 {
10679 /* A closure type for a lambda in an NSDMI or default argument.
10680 Ignore it; it will be regenerated when needed. */
10683 /* Build new CLASSTYPE_NESTED_UTDS. */
10685 tree newtag;
10691 /* If the member is a class template, then -- even after
10692 substitution -- there may be dependent types in the
10693 template argument list for the class. We increment
10694 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10695 that function will assume that no types are dependent
10696 when outside of a template. */
10706 {
10710 /* Unfortunately, lookup_template_class sets
10711 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10712 instantiation (i.e., for the type of a member
10713 template class nested within a template class.)
10714 This behavior is required for
10715 maybe_process_partial_specialization to work
10716 correctly, but is not accurate in this case;
10717 the TAG is not an instantiation of anything.
10718 (The corresponding TEMPLATE_DECL is an
10719 instantiation, but the TYPE is not.) */
10722 /* Now, we call pushtag to put this NEWTAG into the scope of
10723 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10724 pushtag calling push_template_decl. We don't have to do
10725 this for enums because it will already have been done in
10726 tsubst_enum. */
10730 }
10731 }
10733 {
10734 tree r;
10743 /* Instantiate members marked with attribute used. */
10749 }
10752 /* A closure type for a lambda in an NSDMI or default argument.
10754 else
10755 {
10756 /* Build new TYPE_FIELDS. */
10758 {
10759 tree condition;
10762 condition =
10772 }
10774 {
10775 tree r;
10779 /* The file and line for this declaration, to
10780 assist in error message reporting. Since we
10781 called push_tinst_level above, we don't need to
10782 restore these. */
10792 {
10793 /* A capture pack became multiple fields. */
10796 }
10799 {
10803 {
10804 /* In [temp.inst]:
10806 [t]he initialization (and any associated
10807 side-effects) of a static data member does
10808 not occur unless the static data member is
10809 itself used in a way that requires the
10810 definition of the static data member to
10811 exist.
10813 Therefore, we do not substitute into the
10814 initialized for the static data member here. */
10815 finish_static_data_member_decl
10821 /* Instantiate members marked with attribute used. */
10824 }
10826 {
10827 /* Determine whether R has a valid type and can be
10828 completed later. If R is invalid, then its type
10829 is replaced by error_mark_node. */
10835 {
10836 /* If R's type couldn't be completed and
10837 it isn't a flexible array member (whose
10838 type is incomplete by definition) give
10839 an error. */
10842 }
10843 }
10845 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10846 such a thing will already have been added to the field
10847 list by tsubst_enum in finish_member_declaration in the
10848 CLASSTYPE_NESTED_UTDS case above. */
10852 {
10855 }
10856 }
10857 }
10858 }
10859 }
10860 else
10861 {
10864 {
10865 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10871 {
10872 /* template <class T> friend class C; */
10875 }
10877 {
10878 /* template <class T> friend class C::D; */
10884 }
10887 {
10888 /* This could be either
10890 friend class T::C;
10892 when dependent_type_p is false or
10894 template <class U> friend class T::C;
10896 otherwise. */
10897 /* Bump processing_template_decl in case this is something like
10898 template <class T> friend struct A<T>::B. */
10905 }
10909 {
10910 /* friend class C;
10912 where C hasn't been declared yet. Let's lookup name
10913 from namespace scope directly, bypassing any name that
10914 come from dependent base class. */
10917 /* The call to xref_tag_from_type does injection for friend
10918 classes. */
10920 friend_type =
10924 }
10926 /* friend class C<T>; */
10929 /* Otherwise it's
10931 friend class C;
10933 where C is already declared or
10935 friend class C<int>;
10937 We don't have to do anything in these cases. */
10940 /* Trick make_friend_class into realizing that the friend
10941 we're adding is a template, not an ordinary class. It's
10942 important that we use make_friend_class since it will
10943 perform some error-checking and output cross-reference
10944 information. */
10952 }
10953 else
10954 {
10955 /* Build new DECL_FRIENDLIST. */
10956 tree r;
10958 /* The file and line for this declaration, to
10959 assist in error message reporting. Since we
10960 called push_tinst_level above, we don't need to
10961 restore these. */
10965 {
10968 }
10973 {
10976 }
10977 }
10978 }
10979 }
10982 {
10983 /* Restore these before substituting into the lambda capture
10984 initializers. */
10987 }
10989 /* Set the file and line number information to whatever is given for
10990 the class itself. This puts error messages involving generated
10991 implicit functions at a predictable point, and the same point
10992 that would be used for non-template classes. */
10999 /* We don't instantiate default arguments for member functions. 14.7.1:
11001 The implicit instantiation of a class template specialization causes
11002 the implicit instantiation of the declarations, but not of the
11003 definitions or default arguments, of the class member functions,
11004 member classes, static data members and member templates.... */
11006 /* Some typedefs referenced from within the template code need to be access
11007 checked at template instantiation time, i.e now. These types were
11008 added to the template at parsing time. Let's get those and perform
11009 the access checks then. */
11019 /* The vtable for a template class can be emitted in any translation
11020 unit in which the class is instantiated. When there is no key
11021 method, however, finish_struct_1 will already have added TYPE to
11022 the keyed_classes. */
11027 }
11029 /* Wrapper for instantiate_class_template_1. */
11031 tree
11033 {
11034 tree ret;
11039 }
11041 static tree
11043 {
11044 tree r;
11050 else
11051 {
11058 }
11060 }
11062 /* Given a function parameter pack TMPL_PARM and some function parameters
11063 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11064 and set *SPEC_P to point at the next point in the list. */
11066 tree
11068 {
11069 /* Collect all of the extra "packed" parameters into an
11070 argument pack. */
11071 tree parmvec;
11081 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11085 {
11090 }
11092 /* Build the argument packs. */
11097 }
11099 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11100 NONTYPE_ARGUMENT_PACK. */
11102 static tree
11104 {
11106 }
11108 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11109 pack expansion with no extra args, 2 if it has extra args, or 0
11110 if it is not a pack expansion. */
11112 static int
11114 {
11120 /* A decl pack is itself an expansion. */
11127 }
11130 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11132 static tree
11134 {
11141 }
11143 /* This is a subroutine of tsubst_pack_expansion.
11145 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11146 mechanism to store the (non complete list of) arguments of the
11147 substitution and return a non substituted pack expansion, in order
11148 to wait for when we have enough arguments to really perform the
11149 substitution. */
11151 static bool
11155 {
11156 /* If one pack has an expansion and another pack has a normal
11157 argument or if one pack has an empty argument and an another
11158 one hasn't then tsubst_pack_expansion cannot perform the
11159 substitution and need to fall back on the
11160 PACK_EXPANSION_EXTRA mechanism. */
11168 {
11171 parm_pack;
11173 {
11178 /* We can't substitute a pack expansion with extra args into
11179 our pattern. */
11183 else
11185 }
11189 }
11191 }
11193 /* [temp.variadic]/6 says that:
11195 The instantiation of a pack expansion [...]
11196 produces a list E1,E2, ..., En, where N is the number of elements
11197 in the pack expansion parameters.
11199 This subroutine of tsubst_pack_expansion produces one of these Ei.
11201 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11202 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11203 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11204 INDEX is the index 'i' of the element Ei to produce. ARGS,
11205 COMPLAIN, and IN_DECL are the same parameters as for the
11206 tsubst_pack_expansion function.
11208 The function returns the resulting Ei upon successful completion,
11209 or error_mark_node.
11211 Note that this function possibly modifies the ARGS parameter, so
11212 it's the responsibility of the caller to restore it. */
11214 static tree
11216 tree parm_packs,
11218 tree args /* This parm gets
11220 tsubst_flags_t complain,
11221 tree in_decl)
11222 {
11223 tree t;
11226 /* For each parameter pack, change the substitution of the parameter
11227 pack to the ith argument in its argument pack, then expand the
11228 pattern. */
11230 {
11235 ith_elem_is_expansion |=
11238 /* Select the Ith argument from the pack. */
11242 {
11244 {
11249 }
11250 else
11252 }
11253 else
11254 {
11259 {
11261 /* Update the corresponding argument. */
11263 }
11264 else
11265 /* Re-use the ARGUMENT_PACK_SELECT. */
11267 }
11269 }
11271 /* Substitute into the PATTERN with the (possibly altered)
11272 arguments. */
11274 /* Expanding a fixed parameter pack from
11275 coerce_template_parameter_pack. */
11280 {
11283 else
11286 }
11290 else
11293 /* If the Ith argument pack element is a pack expansion, then
11294 the Ith element resulting from the substituting is going to
11295 be a pack expansion as well. */
11300 }
11302 /* When the unexpanded parameter pack in a fold expression expands to an empty
11303 sequence, the value of the expression is as follows; the program is
11304 ill-formed if the operator is not listed in this table.
11306 && true
11307 || false
11308 , void() */
11310 tree
11312 {
11316 {
11325 }
11331 }
11333 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11334 form an expression that combines the two terms using the
11335 operator of T. */
11337 static tree
11339 {
11343 // Handle compound assignment operators.
11348 {
11358 complain);
11359 }
11360 }
11362 /* Substitute ARGS into the pack of a fold expression T. */
11366 {
11368 }
11370 /* Substitute ARGS into the pack of a fold expression T. */
11374 {
11376 }
11378 /* Expand a PACK of arguments into a grouped as left fold.
11379 Given a pack containing elements A0, A1, ..., An and an
11380 operator @, this builds the expression:
11382 ((A0 @ A1) @ A2) ... @ An
11384 Note that PACK must not be empty.
11386 The operator is defined by the original fold expression T. */
11388 static tree
11390 {
11393 {
11396 }
11398 }
11400 /* Substitute into a unary left fold expression. */
11402 static tree
11404 tree in_decl)
11405 {
11410 {
11414 }
11417 else
11419 }
11421 /* Substitute into a binary left fold expression.
11423 Do ths by building a single (non-empty) vector of argumnts and
11424 building the expression from those elements. */
11426 static tree
11428 tree in_decl)
11429 {
11438 {
11443 }
11451 }
11453 /* Expand a PACK of arguments into a grouped as right fold.
11454 Given a pack containing elementns A0, A1, ..., and an
11455 operator @, this builds the expression:
11457 A0@ ... (An-2 @ (An-1 @ An))
11459 Note that PACK must not be empty.
11461 The operator is defined by the original fold expression T. */
11463 tree
11465 {
11466 // Build the expression.
11470 {
11473 }
11475 }
11477 /* Substitute into a unary right fold expression. */
11479 static tree
11481 tree in_decl)
11482 {
11487 {
11491 }
11494 else
11496 }
11498 /* Substitute into a binary right fold expression.
11500 Do ths by building a single (non-empty) vector of arguments and
11501 building the expression from those elements. */
11503 static tree
11505 tree in_decl)
11506 {
11515 {
11520 }
11529 }
11531 /* Walk through the pattern of a pack expansion, adding everything in
11532 local_specializations to a list. */
11534 struct el_data
11535 {
11536 tree extra;
11537 tsubst_flags_t complain;
11538 };
11539 static tree
11541 {
11546 {
11548 {
11549 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11552 {
11558 }
11560 {
11561 /* Handle lambda capture here, since we aren't doing any
11562 substitution now, and so tsubst_copy won't call
11563 process_outer_var_ref. */
11567 {
11573 {
11574 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11575 proxies. */
11577 {
11582 }
11584 }
11585 }
11586 }
11587 }
11591 }
11593 }
11594 static tree
11596 {
11600 }
11602 /* Substitute ARGS into T, which is an pack expansion
11603 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11604 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11605 (if only a partial substitution could be performed) or
11606 ERROR_MARK_NODE if there was an error. */
11607 tree
11609 tree in_decl)
11610 {
11611 tree pattern;
11616 tree result;
11624 /* Add in any args remembered from an earlier partial instantiation. */
11627 {
11629 {
11630 /* The partial instantiation involved local declarations collected in
11631 extract_local_specs; map from the general template to our local
11632 context. */
11638 /* else inst is already a full instantiation of the pack. */
11640 }
11643 }
11648 /* Determine the argument packs that will instantiate the parameter
11649 packs used in the expansion expression. While we're at it,
11650 compute the number of arguments to be expanded and make sure it
11651 is consistent. */
11654 {
11661 {
11666 else
11669 }
11671 {
11672 /* ??? Support use in other patterns. */
11676 }
11678 {
11679 /* We know we have correct local_specializations if this
11680 expansion is at function scope, or if we're dealing with a
11681 local parameter in a requires expression; for the latter,
11682 tsubst_requires_expr set it up appropriately. */
11685 else
11686 /* We can't rely on local_specializations for a parameter
11687 name used later in a function declaration (such as in a
11688 late-specified return type). Even if it exists, it might
11689 have the wrong value for a recursive call. */
11693 {
11694 /* This parameter pack was used in an unevaluated context. Just
11695 make a dummy decl, since it's only used for its type. */
11698 /* Partial instantiation of the parm_pack, we can't build
11699 up an argument pack yet. */
11701 else
11703 }
11705 /* This argument pack isn't fully instantiated yet. We set this
11706 flag rather than clear arg_pack because we do want to do the
11707 optimization below, and we don't want to substitute directly
11708 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11709 where it isn't expected). */
11711 }
11713 {
11717 }
11718 else
11719 {
11725 }
11732 /* This can only happen if we forget to expand an argument
11733 pack somewhere else. Just return an error, silently. */
11734 {
11738 }
11741 {
11745 /* Don't bother trying to do a partial substitution with
11746 incomplete packs; we'll try again after deduction. */
11754 {
11759 pattern);
11760 else
11762 pattern);
11764 }
11766 /* Keep track of the parameter packs and their corresponding
11767 argument packs. */
11770 }
11771 else
11772 {
11773 /* We can't substitute for this parameter pack. We use a flag as
11774 well as the missing_level counter because function parameter
11775 packs don't have a level. */
11778 }
11779 }
11781 /* If the expansion is just T..., return the matching argument pack, unless
11782 we need to call convert_from_reference on all the elements. This is an
11783 important optimization; see c++/68422. */
11786 {
11789 /* If the argument pack is a single pack expansion, pull it out. */
11794 /* Types need no adjustment, nor does sizeof..., and if we still have
11795 some pack expansion args we won't do anything yet. */
11800 /* Also optimize expression pack expansions if we can tell that the
11801 elements won't have reference type. */
11807 /* Otherwise use the normal path so we get convert_from_reference. */
11808 }
11810 /* We cannot expand this expansion expression, because we don't have
11811 all of the argument packs we need. */
11813 {
11814 /* We got some full packs, but we can't substitute them in until we
11815 have values for all the packs. So remember these until then. */
11824 }
11826 {
11827 /* There were no real arguments, we're just replacing a parameter
11828 pack with another version of itself. Substitute into the
11829 pattern and return a PACK_EXPANSION_*. The caller will need to
11830 deal with that. */
11834 else
11838 }
11843 {
11844 /* We're in a late-specified return type, so create our own local
11845 specializations map; the current map is either NULL or (in the
11846 case of recursive unification) might have bindings that we don't
11847 want to use or alter. */
11850 }
11852 /* For each argument in each argument pack, substitute into the
11853 pattern. */
11857 {
11859 i,
11861 in_decl);
11864 {
11867 }
11868 }
11870 /* Update ARGS to restore the substitution from parameter packs to
11871 their argument packs. */
11873 {
11880 else
11881 {
11889 /* Update the corresponding argument. */
11893 else
11895 }
11896 }
11899 {
11902 }
11904 /* If the dependent pack arguments were such that we end up with only a
11905 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11911 }
11913 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11914 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11915 parameter packs; all parms generated from a function parameter pack will
11916 have the same DECL_PARM_INDEX. */
11918 tree
11920 {
11922 tree patparm;
11925 {
11931 }
11932 else
11933 {
11938 }
11941 }
11943 /* Make an argument pack out of the TREE_VEC VEC. */
11945 static tree
11947 {
11948 tree pack;
11952 else
11953 {
11956 }
11959 }
11961 /* Return an exact copy of template args T that can be modified
11962 independently. */
11964 static tree
11966 {
11974 {
11979 }
11985 }
11987 /* Substitute ARGS into the vector or list of template arguments T. */
11989 static tree
11991 {
12003 {
12005 tree new_arg;
12010 {
12011 /* Substitute into an expansion expression. */
12015 /* Add to the expanded length adjustment the number of
12016 expanded arguments. We subtract one from this
12017 measurement, because the argument pack expression
12018 itself is already counted as 1 in
12019 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12020 the argument pack is empty. */
12022 }
12024 {
12025 /* Substitute into each of the arguments. */
12034 else
12039 }
12040 else
12049 }
12054 /* Make space for the expanded arguments coming from template
12055 argument packs. */
12057 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12058 arguments for a member template.
12059 In that case each TREE_VEC in ORIG_T represents a level of template
12060 arguments, and ORIG_T won't carry any non defaulted argument count.
12061 It will rather be the nested TREE_VECs that will carry one.
12062 In other words, ORIG_T carries a non defaulted argument count only
12063 if it doesn't contain any nested TREE_VEC. */
12065 {
12069 }
12071 {
12075 {
12078 /* Now expand the template argument pack "in place". */
12081 }
12082 else
12083 {
12085 out++;
12086 }
12087 }
12090 }
12092 /* Substitute ARGS into one level PARMS of template parameters. */
12094 static tree
12096 {
12103 {
12111 }
12114 }
12116 /* Return the result of substituting ARGS into the template parameters
12117 given by PARMS. If there are m levels of ARGS and m + n levels of
12118 PARMS, then the result will contain n levels of PARMS. For
12119 example, if PARMS is `template <class T> template <class U>
12120 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12121 result will be `template <int*, double, class V>'. */
12123 static tree
12125 {
12129 /* When substituting into a template, we must set
12130 PROCESSING_TEMPLATE_DECL as the template parameters may be
12131 dependent if they are based on one-another, and the dependency
12132 predicates are short-circuit outside of templates. */
12139 {
12146 }
12151 }
12153 /* Return the result of substituting ARGS into one template parameter
12154 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12155 parameter and which TREE_PURPOSE is the default argument of the
12156 template parameter. */
12158 static tree
12160 {
12181 }
12183 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12184 type T. If T is not an aggregate or enumeration type, it is
12185 handled as if by tsubst. IN_DECL is as for tsubst. If
12186 ENTERING_SCOPE is nonzero, T is the context for a template which
12187 we are presently tsubst'ing. Return the substituted value. */
12189 static tree
12191 tree args,
12192 tsubst_flags_t complain,
12193 tree in_decl,
12195 {
12200 {
12205 /* Fall through. */
12209 {
12210 tree argvec;
12211 tree context;
12212 tree r;
12216 /* In "sizeof(X<I>)" we need to evaluate "I". */
12222 /* First, determine the context for the type we are looking
12223 up. */
12226 {
12229 /* If context is a nested class inside a class template,
12230 it may still need to be instantiated (c++/33959). */
12232 }
12234 /* Then, figure out what arguments are appropriate for the
12235 type we are trying to find. For example, given:
12237 template <class T> struct S;
12238 template <class T, class U> void f(T, U) { S<U> su; }
12240 and supposing that we are instantiating f<int, double>,
12241 then our ARGS will be {int, double}, but, when looking up
12242 S we only want {double}. */
12247 else
12248 {
12252 }
12258 }
12259 else
12260 /* This is not a template type, so there's nothing to do. */
12265 }
12266 }
12270 /* Substitute into the default argument ARG (a default argument for
12271 FN), which has the indicated TYPE. */
12273 tree
12275 tsubst_flags_t complain)
12276 {
12281 /* This can happen in invalid code. */
12296 /* This default argument came from a template. Instantiate the
12297 default argument here, not in tsubst. In the case of
12298 something like:
12300 template <class T>
12301 struct S {
12302 static T t();
12303 void f(T = t());
12304 };
12306 we must be careful to do name lookup in the scope of S<T>,
12307 rather than in the current class. */
12309 /* The "this" pointer is not valid in a default argument. */
12311 {
12316 }
12321 /* The default argument expression may cause implicitly defined
12322 member functions to be synthesized, which will result in garbage
12323 collection. We must treat this situation as if we were within
12324 the body of function so as to avoid collecting live data on the
12325 stack. */
12335 /* Restore the "this" pointer. */
12337 {
12340 }
12347 /* Make sure the default argument is reasonable. */
12353 {
12357 }
12360 }
12362 /* Substitute into all the default arguments for FN. */
12364 static void
12366 {
12367 tree arg;
12368 tree tmpl_args;
12372 /* If this function is not yet instantiated, we certainly don't need
12373 its default arguments. */
12376 /* Don't do this again for clones. */
12382 arg;
12388 complain);
12389 }
12391 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12393 static tree
12395 tree lambda_fntype)
12396 {
12401 /* Nobody should be tsubst'ing into non-template functions. */
12405 {
12406 /* If T is not dependent, just return it. */
12410 /* Calculate the most general template of which R is a
12411 specialization. */
12414 /* We're substituting a lambda function under tsubst_lambda_expr but not
12415 directly from it; find the matching function we're already inside.
12416 But don't do this if T is a generic lambda with a single level of
12417 template parms, as in that case we're doing a normal instantiation. */
12423 /* Calculate the complete set of arguments used to
12424 specialize R. */
12426 (DECL_TEMPLATE_RESULT
12432 /* Check to see if we already have this specialization. */
12434 {
12438 }
12440 /* We can see more levels of arguments than parameters if
12441 there was a specialization of a member template, like
12442 this:
12444 template <class T> struct S { template <class U> void f(); }
12445 template <> template <class U> void S<int>::f(U);
12447 Here, we'll be substituting into the specialization,
12448 because that's where we can find the code we actually
12449 want to generate, but we'll have enough arguments for
12450 the most general template.
12452 We also deal with the peculiar case:
12454 template <class T> struct S {
12455 template <class U> friend void f();
12456 };
12457 template <class U> void f() {}
12458 template S<int>;
12459 template void f<double>();
12461 Here, the ARGS for the instantiation of will be {int,
12462 double}. But, we only need as many ARGS as there are
12463 levels of template parameters in CODE_PATTERN. We are
12464 careful not to get fooled into reducing the ARGS in
12465 situations like:
12467 template <class T> struct S { template <class U> void f(U); }
12468 template <class T> template <> void S<T>::f(int) {}
12470 which we can spot because the pattern will be a
12471 specialization in this case. */
12478 }
12479 else
12480 {
12481 /* This special case arises when we have something like this:
12483 template <class T> struct S {
12484 friend void f<int>(int, double);
12485 };
12487 Here, the DECL_TI_TEMPLATE for the friend declaration
12488 will be an IDENTIFIER_NODE. We are being called from
12489 tsubst_friend_function, and we want only to create a
12490 new decl (R) with appropriate types so that we can call
12491 determine_specialization. */
12494 }
12511 /* If we hit excessive deduction depth, the type is bogus even if
12512 it isn't error_mark_node, so don't build a decl. */
12516 /* We do NOT check for matching decls pushed separately at this
12517 point, as they may not represent instantiations of this
12518 template, and in any case are considered separate under the
12519 discrete model. */
12523 /* Clear out the mangled name and RTL for the instantiation. */
12526 /* Leave DECL_INITIAL set on deleted instantiations. */
12531 /* OpenMP UDRs have the only argument a reference to the declared
12532 type. We want to diagnose if the declared type is a reference,
12533 which is invalid, but as references to references are usually
12534 quietly merged, diagnose it here. */
12536 {
12537 tree argtype
12542 "reference type %qT in "
12546 argtype);
12547 }
12550 /* Type-conversion operator. Reconstruct the name, in
12551 case it's the name of one of the template's parameters. */
12561 {
12565 }
12572 /* If this is an instantiation of a function with internal
12573 linkage, we already know what object file linkage will be
12574 assigned to the instantiation. */
12583 /* We'll re-clone as appropriate in instantiate_template. */
12586 /* If we aren't complaining now, return on error before we register
12587 the specialization so that we'll complain eventually. */
12593 /* When instantiating a constrained member, substitute
12594 into the constraints to create a new constraint. */
12597 {
12600 }
12602 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12603 this in the special friend case mentioned above where
12604 GEN_TMPL is NULL. */
12606 {
12611 tree new_r
12614 /* We instantiated this while substituting into
12615 the type earlier (template/friend54.C). */
12618 /* We're not supposed to instantiate default arguments
12619 until they are called, for a template. But, for a
12620 declaration like:
12622 template <class T> void f ()
12623 { extern void g(int i = T()); }
12625 we should do the substitution when the template is
12626 instantiated. We handle the member function case in
12627 instantiate_class_template since the default arguments
12628 might refer to other members of the class. */
12633 }
12634 else
12637 /* Copy the list of befriending classes. */
12641 {
12645 }
12648 {
12652 /* If this is an instantiation of a member template, clone it.
12653 If it isn't, that'll be handled by
12654 clone_constructors_and_destructors. */
12657 }
12668 /* Possibly limit visibility based on template args. */
12671 {
12675 }
12684 }
12686 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12688 static tree
12690 tree lambda_fntype)
12691 {
12692 /* We can get here when processing a member function template,
12693 member class template, or template template parameter. */
12696 tree spec;
12697 tree tmpl_args;
12698 tree full_args;
12699 tree r;
12703 {
12704 /* Template template parameter is treated here. */
12708 /* If we get a real template back, return it. This can happen in
12709 the context of most_specialized_partial_spec. */
12712 else
12713 /* The new TEMPLATE_DECL was built in
12714 reduce_template_parm_level. */
12717 }
12720 {
12721 /* We might already have an instance of this template.
12722 The ARGS are for the surrounding class type, so the
12723 full args contain the tsubst'd args for the context,
12724 plus the innermost args from the template decl. */
12728 /* Because this is a template, the arguments will still be
12729 dependent, even after substitution. If
12730 PROCESSING_TEMPLATE_DECL is not set, the dependency
12731 predicates will short-circuit. */
12739 /* If this is a default template template argument,
12740 tsubst might not have changed anything. */
12748 }
12750 /* Make a new template decl. It will be similar to the
12751 original, but will record the current template arguments.
12752 We also create a new function declaration, which is just
12753 like the old one, but points to this new template, rather
12754 than the old one. */
12759 // Build new template info linking to the original template decl.
12761 {
12764 }
12765 else
12768 /* The template parameters for this new template are all the
12769 template parameters for the old template, except the
12770 outermost level of parameters. */
12773 complain);
12777 {
12778 tree new_type;
12786 /* For a partial specialization, we need to keep pointing to
12787 the primary template. */
12793 }
12794 else
12795 {
12796 tree new_decl;
12800 else
12810 {
12813 }
12814 else
12815 {
12818 }
12819 }
12829 /* Record this non-type partial instantiation. */
12835 }
12837 /* True if FN is the op() for a lambda in an uninstantiated template. */
12839 bool
12841 {
12846 }
12848 /* We're instantiating a variable from template function TCTX. Return the
12849 corresponding current enclosing scope. This gets complicated because lambda
12850 functions in templates are regenerated rather than instantiated, but generic
12851 lambda functions are subsequently instantiated. */
12853 static tree
12855 {
12864 {
12877 }
12879 }
12881 /* Substitute the ARGS into the T, which is a _DECL. Return the
12882 result of the substitution. Issue error and warning messages under
12883 control of COMPLAIN. */
12885 static tree
12887 {
12888 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12889 location_t saved_loc;
12894 /* Set the filename and linenumber to improve error-reporting. */
12899 {
12909 {
12917 {
12918 /* If there is a local specialization that isn't a
12919 parameter pack, it means that we're doing a "simple"
12920 substitution from inside tsubst_pack_expansion. Just
12921 return the local specialization (which will be a single
12922 parm). */
12929 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12930 the parameters in this function parameter pack. */
12934 {
12937 /* Zero-length parameter packs are boring. Just substitute
12938 into the chain. */
12942 }
12943 else
12944 {
12945 /* All we did was update the type. Make a note of that. */
12948 }
12949 }
12951 /* Loop through all of the parameters we'll build. When T is
12952 a function parameter pack, LEN is the number of expanded
12953 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12956 {
12963 /* We're on the Ith parameter of the function parameter
12964 pack. */
12965 {
12966 /* Get the Ith type. */
12969 /* Rename the parameter to include the index. */
12972 }
12974 /* We're dealing with a normal parameter. */
12982 {
12985 else
12988 }
12998 /* Keep track of the first new parameter we
12999 generate. That's what will be returned to the
13000 caller. */
13004 /* Build a proper chain of parameters when substituting
13005 into a function parameter pack. */
13008 }
13010 /* If cp_unevaluated_operand is set, we're just looking for a
13011 single dummy parameter, so don't keep going. */
13016 /* FIRST_R contains the start of the chain we've built. */
13018 }
13022 {
13029 {
13030 /* This field is a lambda capture pack. Return a TREE_VEC of
13031 the expanded fields to instantiate_class_template_1. */
13035 {
13038 }
13039 else
13040 {
13041 /* All we did was update the type. Make a note of that. */
13044 }
13045 }
13048 {
13051 {
13055 }
13065 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13066 number of bits. */
13072 {
13073 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13074 NSDMI in perform_member_init. Still set DECL_INITIAL
13075 so that we know there is one. */
13080 }
13081 /* We don't have to set DECL_CONTEXT here; it is set by
13082 finish_member_declaration. */
13090 }
13094 }
13098 /* We reach here only for member using decls. We also need to check
13099 uses_template_parms because DECL_DEPENDENT_P is not set for a
13100 using-declaration that designates a member of the current
13101 instantiation (c++/53549). */
13104 {
13108 {
13113 {
13117 {
13120 }
13121 else
13122 {
13125 }
13127 }
13128 }
13129 else
13130 {
13136 else
13137 {
13140 }
13141 }
13142 }
13143 else
13144 {
13147 }
13152 {
13155 tree spec;
13157 tree ctx;
13166 {
13167 /* If this is the canonical decl, we don't have to
13168 mess with instantiations, and often we can't (for
13169 typename, template type parms and such). Note that
13170 TYPE_NAME is not correct for the above test if
13171 we've copied the type for a typedef. */
13177 }
13179 /* Check to see if we already have the specialization we
13180 need. */
13183 {
13184 /* T is a static data member or namespace-scope entity.
13185 We have to substitute into namespace-scope variables
13186 (not just variable templates) because of cases like:
13188 template <class T> void f() { extern T t; }
13190 where the entity referenced is not known until
13191 instantiation time. */
13195 {
13197 complain,
13199 /* If CTX is unchanged, then T is in fact the
13200 specialization we want. That situation occurs when
13201 referencing a static data member within in its own
13202 class. We can use pointer equality, rather than
13203 same_type_p, because DECL_CONTEXT is always
13204 canonical... */
13206 /* ... unless T is a member template; in which
13207 case our caller can be willing to create a
13208 specialization of that template represented
13209 by T. */
13213 }
13216 {
13221 argvec = (coerce_innermost_template_parms
13229 }
13230 }
13231 else
13232 {
13233 /* A local variable. */
13235 /* Subsequent calls to pushdecl will fill this in. */
13237 /* Unless this is a reference to a static variable from an
13238 enclosing function, in which case we need to fill it in now. */
13240 {
13244 }
13246 }
13247 /* If we already have the specialization we need, there is
13248 nothing more to do. */
13250 {
13253 }
13255 /* Create a new node for the specialization we need. */
13258 {
13261 else
13269 {
13270 /* Mask off any template args past the variable's context so we
13271 don't replace the auto with an unrelated argument. */
13275 /* This should never happen with the new lambda instantiation
13276 model, but keep the handling just in case. */
13279 }
13281 }
13283 {
13284 /* Even if the original location is out of scope, the
13285 newly substituted one is not. */
13292 {
13293 /* It may seem that this case cannot occur, since:
13295 typedef void f();
13296 void g() { f x; }
13298 declares a function, not a variable. However:
13300 typedef void f();
13301 template <typename T> void g() { T t; }
13302 template void g<f>();
13304 is an attempt to declare a variable with function
13305 type. */
13307 /* R is not yet sufficiently initialized, so we
13308 just use its name. */
13311 }
13313 /* Wait until cp_finish_decl to set this again, to handle
13314 circular dependency (template/instantiate6.C). */
13319 {
13324 {
13327 }
13329 }
13333 }
13339 /* Clear out the mangled name and RTL for the instantiation. */
13343 /* The initializer must not be expanded until it is required;
13344 see [temp.inst]. */
13348 {
13354 /* Possibly limit visibility based on template args. */
13357 {
13361 }
13363 }
13366 {
13367 /* A static data member declaration is always marked
13368 external when it is declared in-class, even if an
13369 initializer is present. We mimic the non-template
13370 processing here. */
13378 }
13379 else
13380 {
13385 }
13393 /* Preserve a typedef that names a type. */
13395 {
13399 /* An alias template specialization can be dependent
13400 even if its underlying type is not. */
13402 }
13405 }
13410 }
13411 #undef RETURN
13413 out:
13414 /* Restore the file and line information. */
13418 }
13420 /* Substitute into the ARG_TYPES of a function type.
13421 If END is a TREE_CHAIN, leave it and any following types
13422 un-substituted. */
13424 static tree
13426 tree args,
13427 tree end,
13428 tsubst_flags_t complain,
13429 tree in_decl)
13430 {
13431 tree remaining_arg_types;
13435 tree default_arg;
13446 {
13447 /* For a pack expansion, perform substitution on the
13448 entire expression. Later on, we'll handle the arguments
13449 one-by-one. */
13454 /* So that we'll spin through the parameters, one by one. */
13456 else
13457 {
13458 /* We only partially substituted into the parameter
13459 pack. Our type is TYPE_PACK_EXPANSION. */
13462 }
13463 }
13476 {
13478 {
13482 }
13484 }
13485 /* DR 657. */
13489 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13490 top-level qualifiers as required. */
13493 /* We do not substitute into default arguments here. The standard
13494 mandates that they be instantiated only when needed, which is
13495 done in build_over_call. */
13498 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13499 since the new op() won't have any associated template arguments for us
13500 to refer to later. */
13506 {
13507 /* We've instantiated a template before its default arguments
13508 have been parsed. This can happen for a nested template
13509 class, and is not an error unless we require the default
13510 argument in a call of this function. */
13511 remaining_arg_types =
13514 }
13515 else
13516 remaining_arg_types =
13518 }
13521 }
13523 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13524 *not* handle the exception-specification for FNTYPE, because the
13525 initial substitution of explicitly provided template parameters
13526 during argument deduction forbids substitution into the
13527 exception-specification:
13529 [temp.deduct]
13531 All references in the function type of the function template to the
13532 corresponding template parameters are replaced by the specified tem-
13533 plate argument values. If a substitution in a template parameter or
13534 in the function type of the function template results in an invalid
13535 type, type deduction fails. [Note: The equivalent substitution in
13536 exception specifications is done only when the function is instanti-
13537 ated, at which point a program is ill-formed if the substitution
13538 results in an invalid type.] */
13540 static tree
13542 tree args,
13543 tsubst_flags_t complain,
13544 tree in_decl)
13545 {
13546 tree return_type;
13548 tree fntype;
13550 /* The TYPE_CONTEXT is not used for function/method types. */
13553 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13554 failure. */
13558 {
13559 /* Substitute the argument types. */
13571 {
13572 /* DR 1207: 'this' is in scope in the trailing return type. */
13574 }
13576 /* Substitute the return type. */
13580 {
13583 }
13584 }
13585 else
13586 /* Substitute the return type. */
13591 /* DR 486 clarifies that creation of a function type with an
13592 invalid return type is a deduction failure. */
13595 {
13597 {
13600 else
13602 }
13604 }
13605 /* And DR 657. */
13610 {
13611 /* Substitute the argument types. */
13616 }
13618 /* Construct a new type node and return it. */
13620 {
13625 }
13626 else
13627 {
13629 /* Don't pick up extra function qualifiers from the basetype. */
13632 {
13633 /* [temp.deduct]
13635 Type deduction may fail for any of the following
13636 reasons:
13638 -- Attempting to create "pointer to member of T" when T
13639 is not a class type. */
13642 r);
13644 }
13649 }
13656 }
13658 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13659 ARGS into that specification, and return the substituted
13660 specification. If there is no specification, return NULL_TREE. */
13662 static tree
13664 tree args,
13665 tsubst_flags_t complain,
13666 tree in_decl,
13668 {
13669 tree specs;
13670 tree new_specs;
13675 {
13676 /* A noexcept-specifier. */
13681 {
13682 /* Defer instantiation of noexcept-specifiers to avoid
13683 excessive instantiations (c++/49107). */
13686 {
13687 /* We already partially instantiated this member template,
13688 so combine the new args with the old. */
13693 }
13694 else
13695 {
13698 }
13699 }
13700 else
13701 new_specs = tsubst_copy_and_build
13705 }
13707 {
13710 else
13712 {
13713 tree spec;
13718 {
13719 /* Expand the pack expansion type. */
13722 in_decl);
13728 else
13729 {
13730 /* We're substituting into a member template, so
13731 we got a TYPE_PACK_EXPANSION back. Add that
13732 expansion and move on. */
13736 expanded_specs,
13737 complain);
13740 }
13741 }
13744 {
13747 else
13752 complain);
13753 }
13756 }
13757 }
13759 }
13761 /* Take the tree structure T and replace template parameters used
13762 therein with the argument vector ARGS. IN_DECL is an associated
13763 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13764 Issue error and warning messages under control of COMPLAIN. Note
13765 that we must be relatively non-tolerant of extensions here, in
13766 order to preserve conformance; if we allow substitutions that
13767 should not be allowed, we may allow argument deductions that should
13768 not succeed, and therefore report ambiguous overload situations
13769 where there are none. In theory, we could allow the substitution,
13770 but indicate that it should have failed, and allow our caller to
13771 make sure that the right thing happens, but we don't try to do this
13772 yet.
13774 This function is used for dealing with types, decls and the like;
13775 for expressions, use tsubst_expr or tsubst_copy. */
13777 tree
13779 {
13802 else
13807 /* Reuse typedefs. We need to do this to handle dependent attributes,
13808 such as attribute aligned. */
13811 {
13815 {
13816 /* DECL represents an alias template and we want to
13817 instantiate it. */
13821 }
13825 {
13829 }
13834 else
13835 /* The typedef is from a non-template context. */
13839 {
13841 r = cp_build_qualified_type_real
13845 }
13846 else
13847 {
13848 /* We don't have an instantiation yet, so drop the typedef. */
13853 }
13854 }
13871 {
13897 {
13903 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13904 needed. */
13910 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13911 with TREE_SIDE_EFFECTS that indicates this is not an integral
13912 constant expression. */
13915 {
13918 }
13921 }
13927 {
13933 /* Early in template argument deduction substitution, we don't
13934 want to reduce the level of 'auto', or it will be confused
13935 with a normal template parm in subsequent deduction. */
13947 {
13950 /* See through ARGUMENT_PACK_SELECT arguments. */
13953 }
13958 {
13960 /* If ARG is an argument pack, we don't actually want to
13961 perform a substitution here, because substitutions
13962 for argument packs are only done
13963 element-by-element. We can get to this point when
13964 substituting the type of a non-type template
13965 parameter pack, when that type actually contains
13966 template parameter packs from an outer template, e.g.,
13968 template<typename... Types> struct A {
13969 template<Types... Values> struct B { };
13970 }; */
13974 {
13980 return cp_build_qualified_type_real
13982 }
13984 {
13985 /* We are processing a type constructed from a
13986 template template parameter. */
13997 /* Consider this code:
13999 template <template <class> class Template>
14000 struct Internal {
14001 template <class Arg> using Bind = Template<Arg>;
14002 };
14004 template <template <class> class Template, class Arg>
14005 using Instantiate = Template<Arg>; //#0
14007 template <template <class> class Template,
14008 class Argument>
14009 using Bind =
14010 Instantiate<Internal<Template>::template Bind,
14011 Argument>; //#1
14013 When #1 is parsed, the
14014 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14015 parameter `Template' in #0 matches the
14016 UNBOUND_CLASS_TEMPLATE representing the argument
14017 `Internal<Template>::template Bind'; We then want
14018 to assemble the type `Bind<Argument>' that can't
14019 be fully created right now, because
14020 `Internal<Template>' not being complete, the Bind
14021 template cannot be looked up in that context. So
14022 we need to "store" `Bind<Argument>' for later
14023 when the context of Bind becomes complete. Let's
14024 store that in a TYPENAME_TYPE. */
14028 argvec),
14029 typename_type,
14030 complain);
14032 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14033 are resolving nested-types in the signature of a
14034 member function templates. Otherwise ARG is a
14035 TEMPLATE_DECL and is the real template to be
14036 instantiated. */
14044 complain);
14045 return cp_build_qualified_type_real
14047 }
14050 else
14051 /* TEMPLATE_PARM_INDEX. */
14053 }
14056 /* This can happen during the attempted tsubst'ing in
14057 unify. This means that we don't yet have any information
14058 about the template parameter in question. */
14061 /* If we get here, we must have been looking at a parm for a
14062 more deeply nested template. Make a new version of this
14063 template parameter, but with a lower level. */
14065 {
14070 {
14072 r = cp_build_qualified_type_real
14076 }
14083 /* Break infinite recursion when substituting the constraints
14085 else
14086 {
14097 {
14098 /* Propagate constraints on placeholders. */
14103 {
14107 }
14108 }
14111 /* We have reduced the level of the template
14112 template parameter, but not the levels of its
14113 template parameters, so canonical_type_parameter
14114 will not be able to find the canonical template
14115 template parameter for this level. Thus, we
14116 require structural equality checking to compare
14117 TEMPLATE_TEMPLATE_PARMs. */
14121 else
14125 {
14127 /* We might need to substitute into the types of non-type
14128 template parameters. */
14140 }
14141 }
14145 /* OK, now substitute the type of the non-type parameter. We
14146 couldn't do it earlier because it might be an auto parameter,
14147 and we wouldn't need to if we had an argument. */
14156 }
14159 }
14162 {
14170 {
14174 }
14177 {
14181 }
14184 {
14188 }
14194 }
14197 /* We should never be tsubsting a binfo. */
14201 /* A vector of template arguments. */
14207 {
14211 /* [temp.deduct]
14213 Type deduction may fail for any of the following
14214 reasons:
14216 -- Attempting to create a pointer to reference type.
14217 -- Attempting to create a reference to a reference type or
14218 a reference to void.
14220 Core issue 106 says that creating a reference to a reference
14221 during instantiation is no longer a cause for failure. We
14222 only enforce this check in strict C++98 mode. */
14226 {
14229 /* We keep track of the last time we issued this error
14230 message to avoid spewing a ton of messages during a
14231 single bad template instantiation. */
14234 {
14239 else
14242 }
14245 }
14249 {
14251 {
14254 type);
14255 else
14257 type);
14258 }
14260 }
14262 {
14266 }
14268 /* In C++0x, during template argument substitution, when there is an
14269 attempt to create a reference to a reference type, reference
14270 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14272 "If a template-argument for a template-parameter T names a type
14273 that is a reference to a type A, an attempt to create the type
14274 'lvalue reference to cv T' creates the type 'lvalue reference to
14275 A,' while an attempt to create the type type rvalue reference to
14276 cv T' creates the type T"
14277 */
14278 r = cp_build_reference_type
14281 else
14286 /* Will this ever be needed for TYPE_..._TO values? */
14290 }
14292 {
14295 {
14296 /* [temp.deduct]
14298 Type deduction may fail for any of the following
14299 reasons:
14301 -- Attempting to create "pointer to member of T" when T
14302 is not a class type. */
14306 }
14308 {
14312 }
14314 {
14318 }
14321 {
14322 /* The type of the implicit object parameter gets its
14323 cv-qualifiers from the FUNCTION_TYPE. */
14324 tree memptr;
14325 tree method_type
14330 complain);
14331 }
14332 else
14335 complain);
14336 }
14339 {
14340 tree fntype;
14341 tree specs;
14346 /* Substitute the exception specification. */
14354 }
14356 {
14361 /* As an optimization, we avoid regenerating the array type if
14362 it will obviously be the same as T. */
14366 /* These checks should match the ones in create_array_type_for_decl.
14368 [temp.deduct]
14370 The deduction may fail for any of the following reasons:
14372 -- Attempting to create an array with an element type that
14373 is void, a function type, or a reference type, or [DR337]
14374 an abstract class type. */
14380 {
14384 }
14392 {
14395 }
14398 }
14401 {
14413 {
14417 }
14419 {
14420 /* Normally, make_typename_type does not require that the CTX
14421 have complete type in order to allow things like:
14423 template <class T> struct S { typename S<T>::X Y; };
14425 But, such constructs have already been resolved by this
14426 point, so here CTX really should have complete type, unless
14427 it's a partial instantiation. */
14430 {
14434 }
14435 }
14442 {
14445 }
14448 {
14450 {
14454 else
14456 }
14458 {
14462 else
14464 }
14465 }
14467 return cp_build_qualified_type_real
14469 }
14472 {
14484 }
14487 {
14488 tree type;
14504 complain);
14505 }
14508 {
14509 tree type;
14520 {
14522 {
14526 }
14529 }
14540 else
14541 {
14545 /* In a template ~id could be either a complement expression
14546 or an unqualified-id naming a destructor; if instantiating
14547 it produces an expression, it's not an id-expression or
14548 member access. */
14551 }
14556 }
14559 {
14563 }
14567 {
14568 tree r;
14572 else
14580 }
14595 /* We should use one of the expression tsubsts for these codes. */
14601 }
14602 }
14604 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14605 expression on the left-hand side of the "." or "->" operator. We
14606 only do the lookup if we had a dependent BASELINK. Otherwise we
14607 adjust it onto the instantiated heirarchy. */
14609 static tree
14612 {
14624 {
14631 }
14638 {
14644 /* Treat as-if non-dependent below. */
14649 {
14655 }
14659 }
14660 else
14661 /* We're going to overwrite pieces below, make a duplicate. */
14664 /* If lookup found a single function, mark it as used at this point.
14665 (If lookup found multiple functions the one selected later by
14666 overload resolution will be marked as used at that point.) */
14672 {
14673 /* Add back the template arguments, if present. */
14678 /* Update the conversion operator type. */
14680 }
14686 {
14688 qualifying_scope,
14689 object_type);
14691 /* We need to call adjust_result_of_qualified_name_lookup in case the
14692 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14693 so that we still get virtual function binding. */
14695 }
14698 }
14700 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14701 true if the qualified-id will be a postfix-expression in-and-of
14702 itself; false if more of the postfix-expression follows the
14703 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14704 of "&". */
14706 static tree
14710 {
14711 tree expr;
14712 tree scope;
14713 tree name;
14715 tree template_args;
14720 /* Figure out what name to look up. */
14723 {
14733 }
14734 else
14735 {
14738 }
14740 /* Substitute into the qualifying scope. When there are no ARGS, we
14741 are just trying to simplify a non-dependent expression. In that
14742 case the qualifying scope may be dependent, and, in any case,
14743 substituting will not help. */
14746 {
14749 }
14750 else
14754 {
14761 }
14764 {
14766 {
14767 /* A BIT_NOT_EXPR is used to represent a destructor. */
14769 {
14773 }
14774 else
14777 }
14778 else
14782 {
14784 {
14788 }
14790 }
14791 }
14794 {
14796 scope);
14797 /* Remember that there was a reference to this entity. */
14800 }
14803 {
14809 }
14812 {
14815 complain);
14816 else
14818 }
14824 {
14825 expr = (adjust_result_of_qualified_name_lookup
14827 expr = (finish_qualified_id_expr
14831 }
14833 /* Expressions do not generally have reference type. */
14835 /* However, if we're about to form a pointer-to-member, we just
14836 want the referenced member referenced. */
14844 }
14846 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14847 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14848 for tsubst. */
14850 static tree
14853 {
14860 {
14861 /* If we had an initializer but it
14862 instantiated to nothing,
14863 value-initialize the object. This will
14864 only occur when the initializer was a
14865 pack expansion where the parameter packs
14866 used in that expansion were of length
14867 zero. */
14869 complain);
14874 }
14877 }
14879 /* Like tsubst, but deals with expressions. This function just replaces
14880 template parms; to finish processing the resultant expression, use
14881 tsubst_copy_and_build or tsubst_expr. */
14883 static tree
14885 {
14887 tree r;
14895 {
14900 {
14901 /* We get here for a use of 'this' in an NSDMI. */
14905 /* This can happen for a parameter name used later in a function
14906 declaration (such as in a late-specified return type). Just
14907 make a dummy decl, since it's only used for its type. */
14910 /* Give it the template pattern as its context; its true context
14911 hasn't been instantiated yet and this is good enough for
14912 mangling. */
14914 }
14923 {
14924 tree enum_type;
14925 tree v;
14929 /* There is no need to substitute into namespace-scope
14930 enumerators. */
14933 /* If ARGS is NULL, then T is known to be non-dependent. */
14937 /* Unfortunately, we cannot just call lookup_name here.
14938 Consider:
14940 template <int I> int f() {
14941 enum E { a = I };
14942 struct S { void g() { E e = a; } };
14943 };
14945 When we instantiate f<7>::S::g(), say, lookup_name is not
14946 clever enough to find f<7>::a. */
14947 enum_type
14957 /* We didn't find the name. That should never happen; if
14958 name-lookup found it during preliminary parsing, we
14959 should find it again here during instantiation. */
14961 }
14966 {
14967 tree ctx;
14972 {
14975 {
14979 }
14981 }
14982 }
14992 {
14995 {
14996 /* First try name lookup to find the instantiation. */
14999 {
15000 /* Make sure that the one we found is the one we want. */
15004 }
15008 else
15009 {
15010 /* This can happen for a variable used in a
15011 late-specified return type of a local lambda, or for a
15012 local static or constant. Building a new VAR_DECL
15013 should be OK in all those cases. */
15016 /* Avoid infinite recursion (79640). */
15019 {
15020 /* We can't call cp_finish_decl, so handle the
15021 initializer by hand. */
15036 }
15043 }
15044 /* Remember this for subsequent uses. */
15047 }
15050 }
15051 else
15061 /* An OVERLOAD will always be a non-dependent overload set; an
15062 overload set from function scope will just be represented with an
15063 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15065 /* We must have marked any lookups as persistent. */
15081 {
15082 /* Template template argument like the following example need
15083 special treatment:
15085 template <template <class> class TT> struct C {};
15086 template <class T> struct D {
15087 template <class U> struct E {};
15088 C<E> c; // #1
15089 };
15090 D<int> d; // #2
15092 We are processing the template argument `E' in #1 for
15093 the template instantiation #2. Originally, `E' is a
15094 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15095 have to substitute this with one having context `D<int>'. */
15099 {
15100 /* When rewriting a constructor into a deduction guide, a
15101 non-dependent name can become dependent, so memtmpl<args>
15102 becomes context::template memtmpl<args>. */
15106 }
15108 }
15109 else
15110 /* Ordinary template template argument. */
15115 {
15116 /* Handle location wrappers by substituting the wrapped node
15117 first, *then* reusing the resulting type. Doing the type
15118 first ensures that we handle template parameters and
15119 parameter pack expansions. */
15123 }
15133 {
15137 }
15142 {
15151 /* We only want to compute the number of arguments. */
15154 else
15161 {
15163 /* Set TREE_USED for the benefit of -Wunused. */
15167 }
15175 {
15180 else
15186 else
15189 }
15190 else
15192 }
15194 {
15202 }
15203 /* Fall through */
15219 {
15223 }
15226 {
15227 tree object;
15228 tree name;
15233 {
15237 }
15240 {
15250 }
15255 in_decl);
15256 else
15259 }
15297 {
15301 }
15304 {
15309 }
15312 {
15316 }
15319 {
15327 }
15333 {
15340 }
15343 {
15350 }
15353 {
15360 }
15363 {
15364 /* Substituted template arguments */
15373 }
15376 {
15396 }
15421 /* Fall through. */
15424 {
15427 }
15428 else
15432 /* This is handled by tsubst_copy_and_build. */
15436 {
15440 }
15443 /* We shouldn't have built any of these during initial template
15444 generation. Instead, they should be built during instantiation
15445 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15449 {
15459 }
15477 {
15478 /* Instantiate any typedefs in the type. */
15483 }
15486 /* These can sometimes show up in a partial instantiation, but never
15487 involve template parms. */
15503 /* ??? There's no point in copying it for now, but maybe some
15504 day it will contain more information, such as a pointer back
15505 to the containing function, inlined copy or so. */
15509 /* We shouldn't get here, but keep going if !flag_checking. */
15513 }
15514 }
15516 /* Helper function for tsubst_omp_clauses, used for instantiation of
15517 OMP_CLAUSE_DECL of clauses. */
15519 static tree
15521 tree in_decl)
15522 {
15526 /* Handle an OpenMP array section represented as a TREE_LIST (or
15527 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15528 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15529 TREE_LIST. We can handle it exactly the same as an array section
15530 (purpose, value, and a chain), even though the nomenclature
15531 (low_bound, length, etc) is different. */
15533 {
15534 tree low_bound
15540 in_decl);
15549 }
15552 /* Undo convert_from_reference tsubst_expr could have called. */
15558 }
15560 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15562 static tree
15565 {
15570 {
15576 {
15579 {
15585 }
15586 /* FALLTHRU */
15601 in_decl);
15633 {
15636 {
15643 }
15644 else
15646 }
15649 in_decl);
15655 in_decl);
15663 in_decl);
15665 {
15668 }
15673 else
15676 in_decl,
15700 }
15703 {
15713 /* tsubst_expr on SCOPE_REF results in returning
15714 finish_non_static_data_member result. Undo that here. */
15718 {
15723 {
15727 CASE_CONVERT:
15736 /* FALLTHRU */
15740 }
15741 }
15747 {
15750 {
15753 }
15754 }
15758 }
15759 }
15763 {
15768 {
15771 }
15772 }
15774 }
15776 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15778 static tree
15780 tree in_decl)
15781 {
15782 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15802 {
15805 else
15806 {
15810 }
15811 }
15816 #undef RECUR
15817 }
15819 /* Used to temporarily communicate the list of #pragma omp parallel
15820 clauses to #pragma omp for instantiation if they are combined
15821 together. */
15825 /* Substitute one OMP_FOR iterator. */
15827 static void
15832 {
15833 #define RECUR(NODE) \
15834 tsubst_expr ((NODE), args, complain, in_decl, \
15835 integral_constant_expression_p)
15842 {
15845 }
15851 {
15852 /* We need to jump through some hoops to handle declarations in the
15853 init-statement, since we might need to handle auto deduction,
15854 but we need to keep control of initialization. */
15858 }
15859 else
15860 {
15862 {
15865 {
15869 {
15873 CASE_CONVERT:
15881 {
15884 }
15885 /* FALLTHRU */
15889 }
15890 }
15891 }
15892 else
15894 }
15905 {
15907 {
15908 /* Declare the variable, but don't let that initialize it. */
15913 }
15918 {
15923 }
15924 else
15931 }
15934 {
15935 /* Declare and initialize the variable. */
15938 }
15940 {
15944 {
15946 {
15952 {
15955 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15960 }
15963 {
15965 decl);
15967 }
15970 {
15972 decl);
15974 }
15975 else
15977 }
15980 }
15982 {
15987 {
15990 }
15991 }
15992 }
15995 {
15999 }
16000 else
16004 {
16015 {
16023 }
16024 else
16030 {
16036 }
16040 {
16048 }
16049 else
16055 }
16061 #undef RECUR
16062 }
16064 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16065 of OMP_TARGET's body. */
16067 static tree
16069 {
16072 {
16081 }
16083 }
16085 /* Helper function for tsubst_expr. For decomposition declaration
16086 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16087 also the corresponding decls representing the identifiers
16088 of the decomposition declaration. Return DECL if successful
16089 or error_mark_node otherwise, set *FIRST to the first decl
16090 in the list chained through DECL_CHAIN and *CNT to the number
16091 of such decls. */
16093 static tree
16097 {
16102 decl2
16107 {
16109 {
16112 }
16129 {
16132 }
16133 else
16135 }
16138 }
16140 /* Like tsubst_copy for expressions, etc. but also does semantic
16141 processing. */
16143 tree
16146 {
16147 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16148 #define RECUR(NODE) \
16149 tsubst_expr ((NODE), args, complain, in_decl, \
16150 integral_constant_expression_p)
16153 tree r;
16154 location_t loc;
16166 {
16168 {
16169 tree_stmt_iterator i;
16173 }
16188 else
16198 {
16200 tree init;
16206 {
16216 else
16218 }
16221 {
16222 /* We're in tsubst_lambda_expr, we've already inserted a new
16223 capture proxy, so look it up and register it. */
16224 tree inst;
16226 {
16227 inst = (retrieve_local_specialization
16230 }
16231 else
16232 {
16236 }
16239 }
16242 /* Don't copy the old closure; we'll create a new one in
16243 tsubst_lambda_expr. */
16245 else
16246 {
16250 {
16251 /* By marking the declaration as instantiated, we avoid
16252 trying to instantiate it. Since instantiate_decl can't
16253 handle local variables, and since we've already done
16254 all that needs to be done, that's the right thing to
16255 do. */
16260 /* Anonymous aggregates are a special case. */
16263 {
16266 {
16270 }
16272 }
16278 {
16283 }
16284 else
16285 {
16290 {
16291 /* For __PRETTY_FUNCTION__ we have to adjust the
16292 initializer. */
16296 }
16297 else
16301 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16306 {
16308 tree first;
16309 tree ndecl
16317 }
16318 else
16320 }
16321 }
16322 }
16325 }
16335 {
16339 }
16344 {
16345 /* Construct another range_for, if this is not a final
16346 substitution (for inside inside a generic lambda of a
16347 template). Otherwise convert to a regular for. */
16349 stmt = (processing_template_decl
16365 {
16369 }
16370 else
16371 {
16377 }
16383 }
16390 {
16394 }
16400 {
16404 }
16417 else
16418 {
16425 }
16431 {
16440 }
16448 else
16456 else
16477 {
16484 }
16488 {
16490 tree label;
16497 }
16503 /* Computed goto's must be tsubst'd into. On the other hand,
16504 non-computed gotos must not be; the identifier in question
16505 will have no binding. */
16507 else
16513 {
16529 }
16534 {
16539 }
16540 else
16541 {
16546 else
16553 else
16559 else
16561 }
16565 {
16569 {
16571 /* Prevent instantiate_decl from trying to instantiate
16572 this variable. We've already done all that needs to be
16573 done. */
16576 }
16581 }
16587 {
16588 /* Local classes are not independent templates; they are
16589 instantiated along with their containing function. And this
16590 way we don't have to deal with pushing out of one local class
16591 to instantiate a member of another local class. */
16592 /* Closures are handled by the LAMBDA_EXPR. */
16602 }
16606 {
16607 tree condition;
16610 condition =
16612 args,
16621 }
16627 in_decl);
16662 {
16675 in_decl);
16677 {
16684 }
16696 integral_constant_expression_p);
16707 else
16708 {
16716 }
16720 }
16725 /* FALLTHRU */
16732 in_decl);
16749 in_decl);
16760 {
16763 {
16764 /* For combined target teams, ensure the num_teams and
16765 thread_limit clause expressions are evaluated on the host,
16766 before entering the target construct. */
16767 tree c;
16773 {
16782 OMP_CLAUSE_FIRSTPRIVATE);
16786 }
16787 }
16788 }
16848 {
16853 {
16856 }
16862 }
16863 else
16864 {
16871 {
16874 }
16877 {
16882 {
16885 }
16891 }
16892 else
16893 {
16897 }
16900 }
16904 {
16910 {
16914 {
16919 }
16923 }
16924 else
16925 {
16930 }
16931 }
16935 {
16939 }
16952 /* If the first operand was a statement, we're done with it. */
16956 complain));
16970 integral_constant_expression_p));
16971 }
16974 out:
16977 #undef RECUR
16978 #undef RETURN
16979 }
16981 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16982 function. For description of the body see comment above
16983 cp_parser_omp_declare_reduction_exprs. */
16985 static void
16987 {
16993 tree_stmt_iterator tsi;
17004 {
17023 }
17025 {
17045 }
17046 }
17048 /* T is a postfix-expression that is not being used in a function
17049 call. Return the substituted version of T. */
17051 static tree
17053 tsubst_flags_t complain,
17054 tree in_decl)
17055 {
17059 else
17065 }
17067 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17068 instantiation context. Instantiating a pack expansion containing a lambda
17069 might result in multiple lambdas all based on the same lambda in the
17070 template. */
17072 tree
17074 {
17088 else
17096 {
17108 else
17113 {
17122 }
17123 else
17124 {
17130 }
17131 }
17135 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17153 else
17154 {
17155 /* Fix the type of 'this'. */
17161 {
17165 }
17166 else
17167 {
17171 }
17173 /* Let finish_function set this. */
17179 else
17180 /* Still increment function_depth so that we don't GC in the
17181 middle of an expression. */
17197 else
17200 /* The capture list was built up in reverse order; fix that now. */
17207 }
17214 }
17216 /* Like tsubst but deals with expressions and performs semantic
17217 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17219 tree
17221 tree args,
17222 tsubst_flags_t complain,
17223 tree in_decl,
17226 {
17227 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17228 #define RECUR(NODE) \
17229 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17231 integral_constant_expression_p)
17234 location_t loc;
17243 /* N3276 decltype magic only applies to calls at the top level or on the
17244 right side of a comma. */
17249 {
17252 /* Fall through. */
17254 {
17255 tree decl;
17256 cp_id_kind idk;
17261 {
17264 }
17266 /* Look up the name. */
17269 /* By convention, expressions use ERROR_MARK_NODE to indicate
17270 failure, not NULL_TREE. */
17276 integral_constant_expression_p,
17284 input_location);
17288 {
17292 }
17294 }
17297 {
17298 tree object;
17308 {
17313 }
17319 {
17322 }
17323 else
17330 else
17332 }
17335 {
17339 {
17340 /* A type conversion to reference type will be enclosed in
17341 such an indirect ref, but the substitution of the cast
17342 will have also added such an indirect ref. */
17344 }
17345 else
17353 }
17356 {
17360 }
17363 {
17367 {
17372 }
17374 /* We'll pass this to convert_nontype_argument again, we don't need
17375 to actually perform any conversion here. */
17381 flags));
17382 }
17385 {
17389 }
17396 {
17397 tree type;
17403 {
17408 }
17415 {
17433 }
17436 }
17470 else
17472 in_decl);
17507 {
17514 tree r = build_x_binary_op
17516 op0,
17518 ? ERROR_MARK
17520 op1,
17522 ? ERROR_MARK
17530 }
17533 {
17537 }
17553 /* Fall through */
17556 {
17557 tree r;
17563 {
17564 /* When there are no ARGS, we are trying to evaluate a
17565 non-dependent expression from the parser. Trying to do
17566 the substitutions may not work. */
17569 }
17570 else
17571 {
17576 else
17579 /*integral_constant_expression_p=*/
17583 }
17587 else
17591 {
17593 {
17595 {
17599 }
17600 else
17604 }
17606 }
17608 }
17611 {
17621 }
17637 {
17641 tree r = build_x_modify_expr
17644 /* TREE_NO_WARNING must be set if either the expression was
17645 parenthesized or it uses an operator such as >>= rather
17646 than plain assignment. In the former case, it was already
17647 set and must be copied. In the latter case,
17648 build_x_modify_expr sets it and it must not be reset
17649 here. */
17654 }
17659 /* Remember that there was a reference to this entity. */
17666 {
17671 tree ret;
17675 else
17676 {
17680 }
17682 /* If there was an initializer in the original tree, but it
17683 instantiated to an empty list, then we should pass a
17684 non-NULL empty vector to tell build_new that it was an
17685 empty initializer() rather than no initializer. This can
17686 only happen when the initializer is a pack expansion whose
17687 parameter packs are of length zero. */
17690 else
17691 {
17695 else
17696 {
17699 }
17700 }
17706 complain);
17714 }
17717 {
17723 complain));
17724 }
17727 {
17731 integral_constant_expression_p);
17733 op0,
17736 }
17739 {
17740 tree function;
17745 tree ret;
17748 /* Internal function with no arguments. */
17752 /* When we parsed the expression, we determined whether or
17753 not Koenig lookup should be performed. */
17756 {
17759 }
17761 {
17766 }
17768 {
17769 /* Do nothing; calling tsubst_copy_and_build on an identifier
17770 would incorrectly perform unqualified lookup again.
17772 Note that we can also have an IDENTIFIER_NODE if the earlier
17773 unqualified lookup found a member function; in that case
17774 koenig_p will be false and we do want to do the lookup
17775 again to find the instantiated member function.
17777 FIXME but doing that causes c++/15272, so we need to stop
17778 using IDENTIFIER_NODE in that situation. */
17780 }
17781 else
17782 {
17784 {
17790 }
17791 else
17796 /* Avoid error about taking the address of a constructor. */
17800 in_decl,
17802 integral_constant_expression_p);
17806 }
17811 {
17816 else
17817 {
17818 /* Expand the pack expansion and push each entry onto
17819 CALL_ARGS. */
17822 {
17827 {
17832 }
17833 }
17834 else
17835 {
17836 /* A partial substitution. Add one entry. */
17838 }
17839 }
17840 }
17842 /* We do not perform argument-dependent lookup if normal
17843 lookup finds a non-function, in accordance with the
17844 expected resolution of DR 218. */
17847 /* If lookup found a member function, the Koenig lookup is
17848 not appropriate, even if an unqualified-name was used
17849 to denote the function. */
17852 /* Only do this when substitution turns a dependent call
17853 into a non-dependent call. */
17861 {
17863 {
17864 /* For backwards compatibility and good diagnostics, try
17865 the unqualified lookup again if we aren't in SFINAE
17866 context. */
17867 tree unq = (tsubst_copy_and_build
17869 integral_constant_expression_p));
17871 {
17874 }
17877 {
17878 /* In a lambda fn, we have to be careful to not
17879 introduce new this captures. Legacy code can't
17880 be using lambdas anyway, so it's ok to be
17881 stricter. */
17886 "and no declarations were found by "
17887 "argument-dependent lookup at the point "
17894 else
17898 {
17909 {
17911 input_location);
17913 "declarations in dependent base %qT are "
17919 else
17923 }
17924 else
17926 "%qD declared here, later in the "
17929 {
17932 }
17933 }
17936 }
17937 }
17939 {
17944 }
17945 }
17947 /* Remember that there was a reference to this entity. */
17951 {
17954 }
17956 /* Put back tf_decltype for the actual call. */
17961 {
17965 {
17967 "wrong number of arguments to "
17970 }
17971 else
17973 input_location),
17978 /* Unsupported internal function with arguments. */
17980 }
17983 complain);
17985 {
18000 complain);
18001 else
18002 ret = (build_new_method_call
18007 complain));
18008 }
18009 else
18012 koenig_p,
18013 complain);
18018 {
18024 {
18030 {
18033 else
18035 /* The thunk location is not interesting. */
18037 }
18038 }
18039 }
18042 }
18045 {
18051 {
18053 {
18058 }
18059 else
18060 {
18065 }
18067 }
18068 else
18069 {
18072 }
18077 }
18080 {
18085 input_location));
18086 }
18089 {
18097 {
18098 /* We have pack expansions, so expand those and
18099 create a new list out of it. */
18102 tree chain;
18105 /* Expand the argument expressions. */
18113 /* Build the rest of the list. */
18118 /* Determine the number of arguments. */
18120 {
18123 }
18126 else
18127 {
18128 /* Since we only performed a partial substitution into
18129 the argument pack, we only RETURN (a single list
18130 node. */
18137 }
18139 /* Convert the argument vectors into a TREE_LIST */
18142 {
18143 /* Grab the Ith values. */
18144 i--;
18147 value
18151 /* Build the list (backwards). */
18153 }
18156 }
18172 }
18175 {
18176 tree object;
18177 tree object_type;
18178 tree member;
18179 tree r;
18183 /* Remember that there was a reference to this entity. */
18194 else
18200 {
18205 }
18209 {
18211 {
18216 {
18219 }
18221 {
18226 }
18227 }
18228 }
18231 {
18232 /* Lookup the template functions now that we know what the
18233 scope is. */
18241 {
18244 args);
18245 member = (adjust_result_of_qualified_name_lookup
18247 object_type));
18248 }
18249 else
18250 {
18252 input_location);
18254 }
18255 }
18259 {
18261 {
18265 else
18268 }
18270 }
18274 complain);
18278 }
18285 {
18293 tree r;
18298 /* We do not want to process the index of aggregate
18299 initializers as they are identifier nodes which will be
18300 looked up by digest_init. */
18306 {
18308 /* An identifier index is looked up in the type
18309 being initialized, not the current scope. */
18314 {
18315 /* Substitute into the pack expansion. */
18317 in_decl);
18321 ;
18323 /* Just move the argument into place. */
18325 else
18326 {
18327 /* Update the length of the final CONSTRUCTOR
18328 arguments vector, and note that we will need to
18329 copy.*/
18332 }
18333 }
18334 else
18336 }
18339 {
18344 {
18346 {
18351 }
18352 else
18354 }
18355 }
18361 {
18366 }
18370 }
18373 {
18376 {
18379 }
18380 else
18381 {
18384 }
18385 }
18390 /* Fall through */
18393 {
18395 /* ??? We're doing a subset of finish_id_expression here. */
18397 && !processing_template_decl
18398 && !cp_unevaluated_operand
18401 {
18403 /* Replace an evaluated use of the thread_local variable with
18404 a call to its wrapper. */
18406 }
18411 /* If the original type was a reference, we'll be wrapped in
18412 the appropriate INDIRECT_REF. */
18415 }
18418 {
18422 }
18425 {
18426 tree object_ptr
18433 }
18440 {
18451 }
18454 {
18460 integral_constant_expression_p);
18464 /* If the resulting list of expression statement is empty,
18465 fold it further into void_node. */
18470 }
18473 {
18477 }
18480 /* We can get here for a constant initializer of non-dependent type.
18481 FIXME stop folding in cp_parser_initializer_clause. */
18482 {
18484 complain);
18486 }
18490 integral_constant_expression_p));
18496 {
18501 complain));
18502 }
18509 /* We should only see these for location wrapper nodes, or within
18510 instantiate_non_dependent_expr (when args is NULL_TREE). */
18515 /* fallthrough. */
18518 /* Handle Objective-C++ constructs, if appropriate. */
18519 {
18520 tree subst
18525 }
18527 }
18529 #undef RECUR
18530 #undef RETURN
18531 out:
18534 }
18536 /* Verify that the instantiated ARGS are valid. For type arguments,
18537 make sure that the type's linkage is ok. For non-type arguments,
18538 make sure they are constants if they are integral or enumerations.
18539 Emit an error under control of COMPLAIN, and return TRUE on error. */
18541 static bool
18543 {
18547 {
18557 }
18559 {
18560 /* [basic.link]: A name with no linkage (notably, the name
18561 of a class or enumeration declared in a local scope)
18562 shall not be used to declare an entity with linkage.
18563 This implies that names with no linkage cannot be used as
18564 template arguments
18566 DR 757 relaxes this restriction for C++0x. */
18571 {
18572 /* DR 488 makes use of a type with no linkage cause
18573 type deduction to fail. */
18575 {
18578 else
18581 }
18583 }
18584 /* In order to avoid all sorts of complications, we do not
18585 allow variably-modified types as template arguments. */
18587 {
18591 }
18592 }
18593 /* Class template and alias template arguments should be OK. */
18595 ;
18596 /* A non-type argument of integral or enumerated type must be a
18597 constant. */
18602 {
18606 }
18608 }
18610 static bool
18612 {
18617 {
18620 }
18624 }
18626 /* We're out of SFINAE context now, so generate diagnostics for the access
18627 errors we saw earlier when instantiating D from TMPL and ARGS. */
18629 static void
18631 {
18643 }
18645 /* Instantiate the indicated variable, function, or alias template TMPL with
18646 the template arguments in TARG_PTR. */
18648 static tree
18650 {
18652 tree fndecl;
18653 tree gen_tmpl;
18654 tree spec;
18662 /* If this function is a clone, handle it specially. */
18664 {
18665 tree spec;
18666 tree clone;
18668 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18669 DECL_CLONED_FUNCTION. */
18675 /* Look for the clone. */
18679 /* We should always have found the clone by now. */
18682 }
18687 /* Check to see if we already have this specialization. */
18691 /* targ_ptr only has the innermost template args, so add the outer ones
18692 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18693 the case of a non-dependent call within a template definition). */
18694 targ_ptr = (add_outermost_template_args
18696 targ_ptr));
18698 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18699 but it doesn't seem to be on the hot path. */
18708 {
18710 {
18714 }
18716 }
18719 complain))
18722 /* We are building a FUNCTION_DECL, during which the access of its
18723 parameters and return types have to be checked. However this
18724 FUNCTION_DECL which is the desired context for access checking
18725 is not built yet. We solve this chicken-and-egg problem by
18726 deferring all checks until we have the FUNCTION_DECL. */
18729 /* Instantiation of the function happens in the context of the function
18730 template, not the context of the overload resolution we're doing. */
18732 /* If there are dependent arguments, e.g. because we're doing partial
18733 ordering, make sure processing_template_decl stays set. */
18737 {
18741 }
18747 {
18748 /* We need to determine if we're using a partial or explicit
18749 specialization now, because the type of the variable could be
18750 different. */
18756 {
18761 }
18762 }
18764 /* Substitute template parameters to obtain the specialization. */
18772 {
18775 }
18777 /* The DECL_TI_TEMPLATE should always be the immediate parent
18778 template, not the most general template. */
18782 /* Now we know the specialization, compute access previously
18783 deferred. Do no access control for inheriting constructors,
18784 as we already checked access for the inherited constructor. */
18787 {
18792 }
18795 /* If we've just instantiated the main entry point for a function,
18796 instantiate all the alternate entry points as well. We do this
18797 by cloning the instantiation of the main entry point, not by
18798 instantiating the template clones. */
18803 {
18805 {
18806 /* Remember to reinstantiate when we're out of SFINAE so the user
18807 can see the errors. */
18809 }
18811 }
18813 }
18815 /* Wrapper for instantiate_template_1. */
18817 tree
18819 {
18820 tree ret;
18825 }
18827 /* Instantiate the alias template TMPL with ARGS. Also push a template
18828 instantiation level, which instantiate_template doesn't do because
18829 functions and variables have sufficient context established by the
18830 callers. */
18832 static tree
18834 {
18841 {
18844 }
18846 args =
18854 /* We can't free this if a pending_template entry or last_error_tinst_level
18855 is pointing at it. */
18861 }
18863 /* PARM is a template parameter pack for FN. Returns true iff
18864 PARM is used in a deducible way in the argument list of FN. */
18866 static bool
18868 {
18871 {
18873 tree packs;
18879 {
18880 /* The template parameter pack is used in a function parameter
18881 pack. If this is the end of the parameter list, the
18882 template parameter pack is deducible. */
18885 else
18886 /* Otherwise, not. Well, it could be deduced from
18887 a non-pack parameter, but doing so would end up with
18888 a deduction mismatch, so don't bother. */
18890 }
18891 }
18892 /* The template parameter pack isn't used in any function parameter
18893 packs, but it might be used deeper, e.g. tuple<Args...>. */
18895 }
18897 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18898 NARGS elements of the arguments that are being used when calling
18899 it. TARGS is a vector into which the deduced template arguments
18900 are placed.
18902 Returns either a FUNCTION_DECL for the matching specialization of FN or
18903 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18904 true, diagnostics will be printed to explain why it failed.
18906 If FN is a conversion operator, or we are trying to produce a specific
18907 specialization, RETURN_TYPE is the return type desired.
18909 The EXPLICIT_TARGS are explicit template arguments provided via a
18910 template-id.
18912 The parameter STRICT is one of:
18914 DEDUCE_CALL:
18915 We are deducing arguments for a function call, as in
18916 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18917 deducing arguments for a call to the result of a conversion
18918 function template, as in [over.call.object].
18920 DEDUCE_CONV:
18921 We are deducing arguments for a conversion function, as in
18922 [temp.deduct.conv].
18924 DEDUCE_EXACT:
18925 We are deducing arguments when doing an explicit instantiation
18926 as in [temp.explicit], when determining an explicit specialization
18927 as in [temp.expl.spec], or when taking the address of a function
18928 template, as in [temp.deduct.funcaddr]. */
18930 tree
18932 tree explicit_targs,
18933 tree targs,
18936 tree return_type,
18937 unification_kind_t strict,
18941 {
18942 tree parms;
18943 tree fntype;
18956 tree tinst;
18962 full_targs = (add_outermost_template_args
18964 targs));
18969 /* In C++0x, it's possible to have a function template whose type depends
18970 on itself recursively. This is most obvious with decltype, but can also
18971 occur with enumeration scope (c++/48969). So we need to catch infinite
18972 recursion and reject the substitution at deduction time; this function
18973 will return error_mark_node for any repeated substitution.
18975 This also catches excessive recursion such as when f<N> depends on
18976 f<N-1> across all integers, and returns error_mark_node for all the
18977 substitutions back up to the initial one.
18979 This is, of course, not reentrant. */
18989 {
18990 /* [temp.deduct]
18992 The specified template arguments must match the template
18993 parameters in kind (i.e., type, nontype, template), and there
18994 must not be more arguments than there are parameters;
18995 otherwise type deduction fails.
18997 Nontype arguments must match the types of the corresponding
18998 nontype template parameters, or must be convertible to the
18999 types of the corresponding nontype parameters as specified in
19000 _temp.arg.nontype_, otherwise type deduction fails.
19002 All references in the function type of the function template
19003 to the corresponding template parameters are replaced by the
19004 specified template argument values. If a substitution in a
19005 template parameter or in the function type of the function
19006 template results in an invalid type, type deduction fails. */
19017 explicit_targs);
19019 /* Adjust any explicit template arguments before entering the
19020 substitution context. */
19021 explicit_targs
19023 complain,
19029 /* Substitute the explicit args into the function type. This is
19030 necessary so that, for instance, explicitly declared function
19031 arguments can match null pointed constants. If we were given
19032 an incomplete set of explicit args, we must not do semantic
19033 processing during substitution as we could create partial
19034 instantiations. */
19036 {
19041 /* Dig out the actual parm. */
19044 {
19047 }
19049 {
19052 }
19055 /* No explicit argument for this template parameter. */
19059 {
19060 /* Mark the argument pack as "incomplete". We could
19061 still deduce more arguments during unification.
19062 We remove this mark in type_unification_real. */
19064 {
19068 }
19070 /* We have some incomplete argument packs. */
19072 }
19073 }
19077 {
19080 }
19083 /* Ignore any access checks; we'll see them again in
19084 instantiate_template and they might have the wrong
19085 access path at this point. */
19097 /* Place the explicitly specified arguments in TARGS. */
19101 }
19103 /* Never do unification on the 'this' parameter. */
19107 {
19108 /* We're deducing for a call to the result of a template conversion
19109 function. The parms we really want are in return_type. */
19113 }
19115 {
19124 }
19126 /* We allow incomplete unification without an error message here
19127 because the standard doesn't seem to explicitly prohibit it. Our
19128 callers must be ready to deal with unification failures in any
19129 event. */
19132 /* If we aren't explaining yet, push tinst context so we can see where
19133 any errors (e.g. from class instantiations triggered by instantiation
19134 of default template arguments) come from. If we are explaining, this
19135 context is redundant. */
19137 {
19140 }
19142 /* type_unification_real will pass back any access checks from default
19143 template argument substitution. */
19155 /* Now that we have bindings for all of the template arguments,
19156 ensure that the arguments deduced for the template template
19157 parameters have compatible template parameter lists. We cannot
19158 check this property before we have deduced all template
19159 arguments, because the template parameter types of a template
19160 template parameter might depend on prior template parameters
19161 deduced after the template template parameter. The following
19162 ill-formed example illustrates this issue:
19164 template<typename T, template<T> class C> void f(C<5>, T);
19166 template<int N> struct X {};
19168 void g() {
19169 f(X<5>(), 5l); // error: template argument deduction fails
19170 }
19172 The template parameter list of 'C' depends on the template type
19173 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19174 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19175 time that we deduce 'C'. */
19178 {
19181 }
19183 /* All is well so far. Now, check:
19185 [temp.deduct]
19187 When all template arguments have been deduced, all uses of
19188 template parameters in nondeduced contexts are replaced with
19189 the corresponding deduced argument values. If the
19190 substitution results in an invalid type, as described above,
19191 type deduction fails. */
19194 {
19197 }
19199 /* Also collect access checks from the instantiation. */
19212 /* Now perform any access checks encountered during substitution. */
19219 /* If we're looking for an exact match, check that what we got
19220 is indeed an exact match. It might not be if some template
19221 parameters are used in non-deduced contexts. But don't check
19222 for an exact match if we have dependent template arguments;
19223 in that case we're doing partial ordering, and we already know
19224 that we have two candidates that will provide the actual type. */
19226 {
19230 tree sarg
19236 {
19240 }
19241 }
19243 /* After doing deduction with the inherited constructor, actually return an
19244 instantiation of the inheriting constructor. */
19250 fail:
19253 {
19255 /* Reset once we're all the way out. */
19257 }
19259 /* We can't free this if a pending_template entry or last_error_tinst_level
19260 is pointing at it. */
19266 }
19268 /* Adjust types before performing type deduction, as described in
19269 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19270 sections are symmetric. PARM is the type of a function parameter
19271 or the return type of the conversion function. ARG is the type of
19272 the argument passed to the call, or the type of the value
19273 initialized with the result of the conversion function.
19274 ARG_EXPR is the original argument expression, which may be null. */
19276 static int
19280 tree arg_expr)
19281 {
19285 {
19290 /* Swap PARM and ARG throughout the remainder of this
19291 function; the handling is precisely symmetric since PARM
19292 will initialize ARG rather than vice versa. */
19297 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19298 too, but here handle it by stripping the reference from PARM
19299 rather than by adding it to ARG. */
19307 /* Nothing else to do in this case. */
19312 }
19315 {
19316 /* [temp.deduct.call]
19318 If P is not a reference type:
19320 --If A is an array type, the pointer type produced by the
19321 array-to-pointer standard conversion (_conv.array_) is
19322 used in place of A for type deduction; otherwise,
19324 --If A is a function type, the pointer type produced by
19325 the function-to-pointer standard conversion
19326 (_conv.func_) is used in place of A for type deduction;
19327 otherwise,
19329 --If A is a cv-qualified type, the top level
19330 cv-qualifiers of A's type are ignored for type
19331 deduction. */
19336 else
19338 }
19340 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19341 reference to a cv-unqualified template parameter that does not represent a
19342 template parameter of a class template (during class template argument
19343 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19344 an lvalue, the type "lvalue reference to A" is used in place of A for type
19345 deduction. */
19352 /* try_one_overload doesn't provide an arg_expr, but
19353 functions are always lvalues. */
19357 /* [temp.deduct.call]
19359 If P is a cv-qualified type, the top level cv-qualifiers
19360 of P's type are ignored for type deduction. If P is a
19361 reference type, the type referred to by P is used for
19362 type deduction. */
19365 {
19368 }
19370 /* DR 322. For conversion deduction, remove a reference type on parm
19371 too (which has been swapped into ARG). */
19376 }
19378 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19379 template which does contain any deducible template parameters; check if
19380 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19381 unify_one_argument. */
19383 static int
19386 {
19387 tree type;
19391 else
19398 {
19402 }
19404 {
19409 }
19413 else
19415 }
19419 /* Returns true iff the expression EXPR is one from which a template
19420 argument can be deduced. In other words, if it's an undecorated
19421 use of a template non-type parameter. */
19423 static bool
19425 {
19426 /* Strip implicit conversions. */
19430 }
19432 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19433 deducible way; that is, if it has a max value of <PARM> - 1. */
19435 static bool
19437 {
19446 }
19448 /* Returns true iff the template arguments ARGS use a template parameter
19449 in a deducible way. */
19451 static bool
19453 {
19455 {
19460 else
19461 {
19468 else
19470 }
19473 }
19475 }
19477 /* Returns true iff TYPE contains any deducible references to template
19478 parameters, as per 14.8.2.5. */
19480 static bool
19482 {
19486 /* T
19487 cv-list T
19488 TT<T>
19489 TT<i>
19490 TT<> */
19495 /* T*
19496 T&
19497 T&& */
19501 /* T[integer-constant ]
19502 type [i] */
19507 /* T type ::*
19508 type T::*
19509 T T::*
19510 T (type ::*)()
19511 type (T::*)()
19512 type (type ::*)(T)
19513 type (T::*)(T)
19514 T (type ::*)(T)
19515 T (T::*)()
19516 T (T::*)(T) */
19519 || (uses_deducible_template_parms
19522 /* template-name <T> (where template-name refers to a class template)
19523 template-name <i> (where template-name refers to a class template) */
19530 /* type (T)
19531 T()
19532 T(T) */
19535 {
19544 }
19547 }
19549 /* Subroutine of type_unification_real and unify_pack_expansion to
19550 handle unification of a single P/A pair. Parameters are as
19551 for those functions. */
19553 static int
19557 {
19564 /* We can't deduce anything from this, but we might get all the
19565 template args from other function args. */
19568 /* Implicit conversions (Clause 4) will be performed on a function
19569 argument to convert it to the type of the corresponding function
19570 parameter if the parameter type contains no template-parameters that
19571 participate in template argument deduction. */
19574 /* For function parameters with no deducible template parameters,
19575 just return. We'll check non-dependent conversions later. */
19579 {
19581 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19582 | UNIFY_ALLOW_MORE_CV_QUAL
19596 }
19598 /* We only do these transformations if this is the top-level
19599 parameter_type_list in a call or declaration matching; in other
19600 situations (nested function declarators, template argument lists) we
19601 won't be comparing a type to an expression, and we don't do any type
19602 adjustments. */
19604 {
19606 {
19609 {
19610 /* [temp.deduct.type] A template-argument can be
19611 deduced from a pointer to function or pointer
19612 to member function argument if the set of
19613 overloaded functions does not contain function
19614 templates and at most one of a set of
19615 overloaded functions provides a unique
19616 match. */
19620 /* If a unique match was not found, this is a
19621 non-deduced context, so we still succeed. */
19623 }
19629 }
19631 arg_strict |=
19633 }
19634 else
19639 /* For deduction from an init-list we need the actual list. */
19643 }
19645 /* for_each_template_parm callback that always returns 0. */
19647 static int
19649 {
19651 }
19653 /* for_each_template_parm any_fn callback to handle deduction of a template
19654 type argument from the type of an array bound. */
19656 static int
19658 {
19666 {
19672 }
19674 /* Keep walking. */
19676 }
19678 /* Try to deduce any not-yet-deduced template type arguments from the type of
19679 an array bound. This is handled separately from unify because 14.8.2.5 says
19680 "The type of a type parameter is only deduced from an array bound if it is
19681 not otherwise deduced." */
19683 static void
19685 {
19690 }
19692 /* Most parms like fn_type_unification.
19694 If SUBR is 1, we're being called recursively (to unify the
19695 arguments of a function or method parameter of a function
19696 template).
19698 CHECKS is a pointer to a vector of access checks encountered while
19699 substituting default template arguments. */
19701 static int
19703 tree full_targs,
19704 tree xparms,
19708 unification_kind_t strict,
19712 {
19717 tree parms;
19728 /* Reset the number of non-defaulted template arguments contained
19729 in TARGS. */
19732 again:
19740 {
19745 /* For a function parameter pack that occurs at the end of the
19746 parameter-declaration-list, the type A of each remaining
19747 argument of the call is compared with the type P of the
19748 declarator-id of the function parameter pack. */
19754 /* For a function parameter pack that does not occur at the
19755 end of the parameter-declaration-list, the type of the
19756 parameter pack is a non-deduced context. */
19763 explain_p))
19765 }
19770 {
19771 /* Unify the remaining arguments with the pack expansion type. */
19772 tree argvec;
19775 /* Allocate a TREE_VEC and copy in all of the arguments */
19780 /* Copy the parameter into parmvec. */
19786 /* Advance to the end of the list of parameters. */
19788 }
19790 /* Fail if we've reached the end of the parm list, and more args
19791 are present, and the parm list isn't variadic. */
19794 /* Fail if parms are left and they don't have default values and
19795 they aren't all deduced as empty packs (c++/57397). This is
19796 consistent with sufficient_parms_p. */
19799 {
19803 do
19804 {
19807 count++;
19809 }
19813 type_pack_p);
19814 }
19817 {
19818 tsubst_flags_t complain = (explain_p
19819 ? tf_warning_or_error
19824 {
19828 /* Clear the "incomplete" flags on all argument packs now so that
19829 substituting them into later default arguments works. */
19831 {
19834 }
19842 {
19847 }
19849 /* If this is an undeduced nontype parameter that depends on
19850 a type parameter, try another pass; its type may have been
19851 deduced from a later argument than the one from which
19852 this parameter can be deduced. */
19856 {
19859 }
19861 /* Core issue #226 (C++0x) [temp.deduct]:
19863 If a template argument has not been deduced, its
19864 default template argument, if any, is used.
19866 When we are in C++98 mode, TREE_PURPOSE will either
19867 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19868 to explicitly check cxx_dialect here. */
19870 /* OK, there is a default argument. Wait until after the
19871 conversion check to do substitution. */
19874 /* If the type parameter is a parameter pack, then it will
19875 be deduced to an empty parameter pack. */
19877 {
19878 tree arg;
19881 {
19884 }
19885 else
19892 }
19895 }
19897 /* DR 1391: All parameters have args, now check non-dependent parms for
19898 convertibility. */
19902 {
19908 /* For a function parameter pack that occurs at the end of the
19909 parameter-declaration-list, the type A of each remaining
19910 argument of the call is compared with the type P of the
19911 declarator-id of the function parameter pack. */
19917 /* For a function parameter pack that does not occur at the
19918 end of the parameter-declaration-list, the type of the
19919 parameter pack is a non-deduced context. */
19928 explain_p))
19930 }
19932 /* Now substitute into the default template arguments. */
19934 {
19944 {
19945 /* When saw_undeduced == 1, substitution into parm and arg might
19946 fail or not replace all template parameters, and that's
19947 fine. */
19952 }
19965 else
19973 {
19975 /* The position of the first default template argument,
19976 is also the number of non-defaulted arguments in TARGS.
19977 Record that. */
19980 }
19981 }
19985 }
19991 }
19993 /* Subroutine of type_unification_real. Args are like the variables
19994 at the call site. ARG is an overloaded function (or template-id);
19995 we try deducing template args from each of the overloads, and if
19996 only one succeeds, we go with that. Modifies TARGS and returns
19997 true on success. */
19999 static bool
20001 tree targs,
20002 tree parm,
20003 tree arg,
20004 unification_kind_t strict,
20007 {
20014 {
20017 }
20018 else
20022 /* Handle `&x' where `x' is some static or non-static member
20023 function name. */
20029 /* Strip baselink information. */
20034 {
20035 /* If we got some explicit template args, we need to plug them into
20036 the affected templates before we try to unify, in case the
20037 explicit args will completely resolve the templates in question. */
20044 {
20057 {
20062 {
20065 }
20066 }
20069 }
20070 /* If no templates (or more than one) are fully resolved by the
20071 explicit arguments, this template-id is a non-deduced context; it
20072 could still be OK if we deduce all template arguments for the
20073 enclosing call through other arguments. */
20076 }
20079 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20080 -- but the deduction does not succeed because the expression is
20081 not just the function on its own. */
20083 else
20085 {
20090 {
20093 }
20094 }
20096 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20097 to function or pointer to member function argument if the set of
20098 overloaded functions does not contain function templates and at most
20099 one of a set of overloaded functions provides a unique match.
20101 So if we found multiple possibilities, we return success but don't
20102 deduce anything. */
20105 {
20109 {
20114 /* Don't forget explicit template arguments in a pack. */
20118 }
20119 }
20124 }
20126 /* Core DR 115: In contexts where deduction is done and fails, or in
20127 contexts where deduction is not done, if a template argument list is
20128 specified and it, along with any default template arguments, identifies
20129 a single function template specialization, then the template-id is an
20130 lvalue for the function template specialization. */
20132 tree
20134 {
20147 {
20150 }
20152 {
20155 }
20157 {
20160 }
20163 {
20167 /* If we got some explicit template args, we need to plug them into
20168 the affected templates before we try to unify, in case the
20169 explicit args will completely resolve the templates in question. */
20177 {
20190 {
20193 {
20196 }
20198 {
20201 }
20202 }
20203 }
20205 {
20213 {
20214 tree base
20217 }
20221 }
20223 /* There were no good options and at least one bad one, so let the
20224 user know what the problem is. */
20226 }
20228 }
20230 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20231 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20232 different overloads deduce different arguments for a given parm.
20233 ADDR_P is true if the expression for which deduction is being
20234 performed was of the form "& fn" rather than simply "fn".
20236 Returns 1 on success. */
20238 static int
20240 tree orig_targs,
20241 tree targs,
20242 tree parm,
20243 tree arg,
20244 unification_kind_t strict,
20248 {
20250 tree tempargs;
20256 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20257 to function or pointer to member function argument if the set of
20258 overloaded functions does not contain function templates and at most
20259 one of a set of overloaded functions provides a unique match.
20261 So if this is a template, just return success. */
20273 /* We don't copy orig_targs for this because if we have already deduced
20274 some template args from previous args, unify would complain when we
20275 try to deduce a template parameter for the same argument, even though
20276 there isn't really a conflict. */
20283 /* First make sure we didn't deduce anything that conflicts with
20284 explicitly specified args. */
20286 {
20293 /* Since we're unifying against ourselves, we will fill in
20294 template args used in the function parm list with our own
20295 template parms. Discard them. */
20298 {
20299 /* Check that the argument at each index of the deduced argument pack
20300 is equivalent to the corresponding explicitly specified argument.
20301 We may have deduced more arguments than were explicitly specified,
20302 and that's OK. */
20304 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20305 that's wrong if we deduce the same argument pack from multiple
20306 function arguments: it's only incomplete the first time. */
20319 }
20322 }
20325 {
20330 }
20333 }
20335 /* PARM is a template class (perhaps with unbound template
20336 parameters). ARG is a fully instantiated type. If ARG can be
20337 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20338 TARGS are as for unify. */
20340 static tree
20343 {
20344 tree copy_of_targs;
20354 /* We need to make a new template argument vector for the call to
20355 unify. If we used TARGS, we'd clutter it up with the result of
20356 the attempted unification, even if this class didn't work out.
20357 We also don't want to commit ourselves to all the unifications
20358 we've already done, since unification is supposed to be done on
20359 an argument-by-argument basis. In other words, consider the
20360 following pathological case:
20362 template <int I, int J, int K>
20363 struct S {};
20365 template <int I, int J>
20366 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20368 template <int I, int J, int K>
20369 void f(S<I, J, K>, S<I, I, I>);
20371 void g() {
20372 S<0, 0, 0> s0;
20373 S<0, 1, 2> s2;
20375 f(s0, s2);
20376 }
20378 Now, by the time we consider the unification involving `s2', we
20379 already know that we must have `f<0, 0, 0>'. But, even though
20380 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20381 because there are two ways to unify base classes of S<0, 1, 2>
20382 with S<I, I, I>. If we kept the already deduced knowledge, we
20383 would reject the possibility I=1. */
20387 {
20391 }
20393 /* If unification failed, we're done. */
20399 }
20401 /* Given a template type PARM and a class type ARG, find the unique
20402 base type in ARG that is an instance of PARM. We do not examine
20403 ARG itself; only its base-classes. If there is not exactly one
20404 appropriate base class, return NULL_TREE. PARM may be the type of
20405 a partial specialization, as well as a plain template type. Used
20406 by unify. */
20408 static enum template_base_result
20411 {
20413 tree binfo;
20419 {
20420 /* The type could not be completed. */
20423 }
20425 /* Walk in inheritance graph order. The search order is not
20426 important, and this avoids multiple walks of virtual bases. */
20428 {
20433 {
20434 /* If there is more than one satisfactory baseclass, then:
20436 [temp.deduct.call]
20438 If they yield more than one possible deduced A, the type
20439 deduction fails.
20441 applies. */
20443 {
20446 }
20449 }
20450 }
20454 }
20456 /* Returns the level of DECL, which declares a template parameter. */
20458 static int
20460 {
20462 {
20472 }
20474 }
20476 /* Decide whether ARG can be unified with PARM, considering only the
20477 cv-qualifiers of each type, given STRICT as documented for unify.
20478 Returns nonzero iff the unification is OK on that basis. */
20480 static int
20482 {
20488 {
20489 /* Although a CVR qualifier is ignored when being applied to a
20490 substituted template parameter ([8.3.2]/1 for example), that
20491 does not allow us to unify "const T" with "int&" because both
20492 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20493 It is ok when we're allowing additional CV qualifiers
20494 at the outer level [14.8.2.1]/3,1st bullet. */
20504 }
20515 }
20517 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20518 void
20520 {
20524 {
20527 }
20528 else
20529 {
20532 }
20533 }
20535 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20536 do { \
20537 if (unify (TP, TA, P, A, S, EP)) \
20538 return 1; \
20539 } while (0)
20541 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20542 expansion at the end of PACKED_PARMS. Returns 0 if the type
20543 deduction succeeds, 1 otherwise. STRICT is the same as in
20544 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20545 function call argument list. We'll need to adjust the arguments to make them
20546 types. SUBR tells us if this is from a recursive call to
20547 type_unification_real, or for comparing two template argument
20548 lists. */
20550 static int
20554 {
20555 tree parm
20561 /* Add in any args remembered from an earlier partial instantiation. */
20569 /* Determine the parameter packs we will be deducing from the
20570 pattern, and record their current deductions. */
20573 {
20577 /* Determine the index and level of this parameter pack. */
20582 /* Keep track of the parameter packs and their corresponding
20583 argument packs. */
20586 }
20588 /* Loop through all of the arguments that have not yet been
20589 unified and unify each with the pattern. */
20591 {
20592 tree parm;
20596 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20597 or the element of its argument pack at the current index if
20598 this argument was explicitly specified. */
20600 {
20609 {
20612 }
20614 }
20616 /* If we had explicit template arguments, substitute them into the
20617 pattern before deduction. */
20619 {
20620 /* Some arguments might still be unspecified or dependent. */
20628 NULL_TREE);
20633 }
20634 else
20637 /* Unify the pattern with the current argument. */
20639 explain_p))
20642 /* For each parameter pack, collect the deduced value. */
20644 {
20650 }
20651 }
20653 /* Verify that the results of unification with the parameter packs
20654 produce results consistent with what we've seen before, and make
20655 the deduced argument packs available. */
20657 {
20664 /* By default keep the original deduced argument pack.
20665 If necessary, more specific code is going to update the
20666 resulting deduced argument later down in this function. */
20670 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20671 actually deduce anything. */
20679 {
20680 /* If we had fewer function args than explicit template args,
20681 just use the explicits. */
20686 }
20689 {
20690 tree result;
20691 /* Build the deduced *_ARGUMENT_PACK. */
20693 {
20696 }
20697 else
20702 /* Note the deduced argument packs for this parameter
20703 pack. */
20705 }
20709 {
20710 /* We only had the explicitly-provided arguments before, but
20711 now we have a complete set of arguments. */
20717 }
20718 else
20719 {
20725 /* Inconsistent unification of this parameter pack. */
20727 bad_old_arg,
20728 bad_new_arg);
20729 }
20730 }
20733 }
20735 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20736 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20737 parameters and return value are as for unify. */
20739 static int
20743 {
20744 tree parm_max;
20745 tree arg_max;
20749 /* Our representation of array types uses "N - 1" as the
20750 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20751 not an integer constant. We cannot unify arbitrarily
20752 complex expressions, so we eliminate the MINUS_EXPRs
20753 here. */
20757 {
20760 }
20764 {
20765 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20766 trying to unify the type of a variable with the type
20767 of a template parameter. For example:
20769 template <unsigned int N>
20770 void f (char (&) [N]);
20771 int g();
20772 void h(int i) {
20773 char a[g(i)];
20774 f(a);
20775 }
20777 Here, the type of the ARG will be "int [g(i)]", and
20778 may be a SAVE_EXPR, etc. */
20782 }
20784 /* If only one of the bounds used a MINUS_EXPR, compensate
20785 by adding one to the other bound. */
20788 integer_type_node,
20789 parm_max,
20790 integer_one_node);
20793 integer_type_node,
20794 arg_max,
20795 integer_one_node);
20799 }
20801 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20805 static pa_kind_t
20807 {
20816 else
20818 }
20820 /* Deduce the value of template parameters. TPARMS is the (innermost)
20821 set of template parameters to a template. TARGS is the bindings
20822 for those template parameters, as determined thus far; TARGS may
20823 include template arguments for outer levels of template parameters
20824 as well. PARM is a parameter to a template function, or a
20825 subcomponent of that parameter; ARG is the corresponding argument.
20826 This function attempts to match PARM with ARG in a manner
20827 consistent with the existing assignments in TARGS. If more values
20828 are deduced, then TARGS is updated.
20830 Returns 0 if the type deduction succeeds, 1 otherwise. The
20831 parameter STRICT is a bitwise or of the following flags:
20833 UNIFY_ALLOW_NONE:
20834 Require an exact match between PARM and ARG.
20835 UNIFY_ALLOW_MORE_CV_QUAL:
20836 Allow the deduced ARG to be more cv-qualified (by qualification
20837 conversion) than ARG.
20838 UNIFY_ALLOW_LESS_CV_QUAL:
20839 Allow the deduced ARG to be less cv-qualified than ARG.
20840 UNIFY_ALLOW_DERIVED:
20841 Allow the deduced ARG to be a template base class of ARG,
20842 or a pointer to a template base class of the type pointed to by
20843 ARG.
20844 UNIFY_ALLOW_INTEGER:
20845 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20846 case for more information.
20847 UNIFY_ALLOW_OUTER_LEVEL:
20848 This is the outermost level of a deduction. Used to determine validity
20849 of qualification conversions. A valid qualification conversion must
20850 have const qualified pointers leading up to the inner type which
20851 requires additional CV quals, except at the outer level, where const
20852 is not required [conv.qual]. It would be normal to set this flag in
20853 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20854 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20855 This is the outermost level of a deduction, and PARM can be more CV
20856 qualified at this point.
20857 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20858 This is the outermost level of a deduction, and PARM can be less CV
20859 qualified at this point. */
20861 static int
20864 {
20866 tree targ;
20867 tree tparm;
20869 tsubst_flags_t complain = (explain_p
20870 ? tf_warning_or_error
20873 /* I don't think this will do the right thing with respect to types.
20874 But the only case I've seen it in so far has been array bounds, where
20875 signedness is the only information lost, and I think that will be
20876 okay. */
20884 /* We can't deduce anything from this, but we might get all the
20885 template args from other function args. */
20891 /* If PARM uses template parameters, then we can't bail out here,
20892 even if ARG == PARM, since we won't record unifications for the
20893 template parameters. We might need them if we're trying to
20894 figure out which of two things is more specialized. */
20898 /* Handle init lists early, so the rest of the function can assume
20899 we're dealing with a type. */
20901 {
20906 /* Replace T with std::initializer_list<T> for deduction. */
20913 /* We can only deduce from an initializer list argument if the
20914 parameter is std::initializer_list or an array; otherwise this
20915 is a non-deduced context. */
20920 else
20921 {
20923 /* Deduction is defined in terms of a single type, so just punt
20924 on the (bizarre) std::initializer_list<T...>. */
20927 }
20930 {
20937 {
20941 /* It should only be possible to get here for a call. */
20943 elt_strict |= maybe_adjust_types_for_deduction
20946 }
20949 explain_p);
20950 }
20954 {
20955 /* Also deduce from the length of the initializer list. */
20962 }
20964 /* If the std::initializer_list<T> deduction worked, replace the
20965 deduced A with std::initializer_list<A>. */
20967 {
20972 }
20974 }
20976 /* If parm and arg aren't the same kind of thing (template, type, or
20977 expression), fail early. */
20981 /* Immediately reject some pairs that won't unify because of
20982 cv-qualification mismatches. */
20985 /* It is the elements of the array which hold the cv quals of an array
20986 type, and the elements might be template type parms. We'll check
20987 when we recurse. */
20989 /* We check the cv-qualifiers when unifying with template type
20990 parameters below. We want to allow ARG `const T' to unify with
20991 PARM `T' for example, when computing which of two templates
20992 is more specialized, for example. */
21006 {
21010 /* In a type which contains a nested-name-specifier, template
21011 argument values cannot be deduced for template parameters used
21012 within the nested-name-specifier. */
21024 /* The PARM is not one we're trying to unify. Just check
21025 to see if it matches ARG. */
21026 {
21031 else
21033 }
21040 /* Check for mixed types and values. */
21048 {
21051 {
21052 /* First try to match ARG directly. */
21054 explain_p);
21056 {
21057 /* Otherwise, look for a suitable base of ARG, as below. */
21064 }
21065 }
21066 /* ARG must be constructed from a template class or a template
21067 template parameter. */
21072 /* Deduce arguments T, i from TT<T> or TT<i>. */
21078 /* Fall through to deduce template name. */
21079 }
21083 {
21084 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21086 /* Simple cases: Value already set, does match or doesn't. */
21091 }
21092 else
21093 {
21094 /* If PARM is `const T' and ARG is only `int', we don't have
21095 a match unless we are allowing additional qualification.
21096 If ARG is `const int' and PARM is just `T' that's OK;
21097 that binds `const int' to `T'. */
21102 /* Consider the case where ARG is `const volatile int' and
21103 PARM is `const T'. Then, T should be `volatile int'. */
21104 arg = cp_build_qualified_type_real
21109 /* Simple cases: Value already set, does match or doesn't. */
21115 /* Make sure that ARG is not a variable-sized array. (Note
21116 that were talking about variable-sized arrays (like
21117 `int[n]'), rather than arrays of unknown size (like
21118 `int[]').) We'll get very confused by such a type since
21119 the bound of the array is not constant, and therefore
21120 not mangleable. Besides, such types are not allowed in
21121 ISO C++, so we can do as we please here. We do allow
21122 them for 'auto' deduction, since that isn't ABI-exposed. */
21126 /* Strip typedefs as in convert_template_argument. */
21128 }
21130 /* If ARG is a parameter pack or an expansion, we cannot unify
21131 against it unless PARM is also a parameter pack. */
21136 /* If the argument deduction results is a METHOD_TYPE,
21137 then there is a problem.
21138 METHOD_TYPE doesn't map to any real C++ type the result of
21139 the deduction can not be of that type. */
21153 {
21154 /* The PARM is not one we're trying to unify. Just check
21155 to see if it matches ARG. */
21161 }
21167 {
21171 /* We're deducing from an array bound, the type doesn't matter. */
21177 }
21179 /* [temp.deduct.type] If, in the declaration of a function template
21180 with a non-type template-parameter, the non-type
21181 template-parameter is used in an expression in the function
21182 parameter-list and, if the corresponding template-argument is
21183 deduced, the template-argument type shall match the type of the
21184 template-parameter exactly, except that a template-argument
21185 deduced from an array bound may be of any integral type.
21186 The non-type parameter might use already deduced type parameters. */
21191 {
21195 }
21198 /* Template-parameter dependent expression. Just accept it for now.
21199 It will later be processed in convert_template_argument. */
21200 ;
21206 /* Convert the ARG to the type of PARM; the deduced non-type
21207 template argument must exactly match the types of the
21208 corresponding parameter. */
21211 {
21212 /* We haven't deduced the type of this parameter yet. */
21214 /* We deduce from array bounds in try_array_deduction. */
21216 {
21217 /* Deduce it from the non-type argument. */
21222 }
21223 else
21224 /* Try again later. */
21226 }
21227 else
21230 /* If ARG is a parameter pack or an expansion, we cannot unify
21231 against it unless PARM is also a parameter pack. */
21236 {
21239 }
21244 {
21245 /* A pointer-to-member constant can be unified only with
21246 another constant. */
21250 /* Just unify the class member. It would be useless (and possibly
21251 wrong, depending on the strict flags) to unify also
21252 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21253 arg refer to the same variable, even if through different
21254 classes. For instance:
21256 struct A { int x; };
21257 struct B : A { };
21259 Unification of &A::x and &B::x must succeed. */
21262 }
21265 {
21269 /* [temp.deduct.call]
21271 A can be another pointer or pointer to member type that can
21272 be converted to the deduced A via a qualification
21273 conversion (_conv.qual_).
21275 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21276 This will allow for additional cv-qualification of the
21277 pointed-to types if appropriate. */
21280 /* The derived-to-base conversion only persists through one
21281 level of pointers. */
21286 }
21318 /* We have already checked cv-qualification at the top of the
21319 function. */
21323 /* As far as unification is concerned, this wins. Later checks
21324 will invalidate it if necessary. */
21327 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21328 /* Type INTEGER_CST can come from ordinary constant template args. */
21340 {
21350 /* Check for pack expansions in the parameters. */
21352 {
21354 {
21356 /* We can unify against something with a trailing
21357 parameter pack. */
21359 else
21360 /* [temp.deduct.type]/9: If the template argument list of
21361 P contains a pack expansion that is not the last
21362 template argument, the entire template argument list
21363 is a non-deduced context. */
21365 }
21366 }
21368 /* If we don't have enough arguments to satisfy the parameters
21369 (not counting the pack expression at the end), or we have
21370 too many arguments for a parameter list that doesn't end in
21371 a pack expression, we can't unify. */
21377 /* Unify all of the parameters that precede the (optional)
21378 pack expression. */
21380 {
21385 }
21388 DEDUCE_EXACT,
21391 }
21399 {
21407 }
21412 {
21416 {
21417 /* First, we try to unify the PARM and ARG directly. */
21422 {
21423 /* Fallback to the special case allowed in
21424 [temp.deduct.call]:
21426 If P is a class, and P has the form
21427 template-id, then A can be a derived class of
21428 the deduced A. Likewise, if P is a pointer to
21429 a class of the form template-id, A can be a
21430 pointer to a derived class pointed to by the
21431 deduced A. */
21437 {
21438 /* Don't give the derived diagnostic if we're
21439 already dealing with the same template. */
21440 bool same_template
21446 }
21447 }
21448 }
21452 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21453 Then, we should unify `int' and `U'. */
21455 else
21456 /* There's no chance of unification succeeding. */
21461 }
21468 {
21471 tree a;
21477 /* CV qualifications for methods can never be deduced, they must
21478 match exactly. We need to check them explicitly here,
21479 because type_unification_real treats them as any other
21480 cv-qualified parameter. */
21482 && (!check_cv_quals_for_unify
21510 {
21522 }
21525 }
21528 /* Unify a pointer to member with a pointer to member function, which
21529 deduces the type of the member as a function type. */
21531 {
21532 /* Check top-level cv qualifiers */
21540 /* Determine the type of the function we are unifying against. */
21544 }
21563 /* Matched cases are handled by the ARG == PARM test above. */
21567 /* We might get a variable as a non-type template argument in parm if the
21568 corresponding parameter is type-dependent. Make any necessary
21569 adjustments based on whether arg is a reference. */
21573 {
21578 }
21579 /* Now use the normal expression code to check whether they match. */
21590 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21591 or UNDERLYING_TYPE nodes. */
21595 /* Unification fails if we hit an error node. */
21600 {
21610 }
21611 /* FALLTHRU */
21614 /* An unresolved overload is a nondeduced context. */
21618 expr:
21619 /* We must be looking at an expression. This can happen with
21620 something like:
21622 template <int I>
21623 void foo(S<I>, S<I + 2>);
21625 This is a "nondeduced context":
21627 [deduct.type]
21629 The nondeduced contexts are:
21631 --A type that is a template-id in which one or more of
21632 the template-arguments is an expression that references
21633 a template-parameter.
21635 In these cases, we assume deduction succeeded, but don't
21636 actually infer any unifications. */
21641 else
21643 }
21644 }
21645 #undef RECUR_AND_CHECK_FAILURE
21646 \f
21647 /* Note that DECL can be defined in this translation unit, if
21648 required. */
21650 static void
21652 {
21653 tree clone;
21657 }
21659 /* Called if RESULT is explicitly instantiated, or is a member of an
21660 explicitly instantiated class. */
21662 void
21664 {
21667 /* If this entity has already been written out, it's too late to
21668 make any modifications. */
21672 /* For anonymous namespace we don't need to do anything. */
21674 {
21677 }
21680 /* The TREE_PUBLIC flag for function declarations will have been
21681 set correctly by tsubst. */
21684 /* This might have been set by an earlier implicit instantiation. */
21689 else
21690 {
21693 /* Always make artificials weak. */
21696 /* For WIN32 we also want to put explicit instantiations in
21697 linkonce sections. */
21700 }
21702 /* If EXTERN_P, then this function will not be emitted -- unless
21703 followed by an explicit instantiation, at which point its linkage
21704 will be adjusted. If !EXTERN_P, then this function will be
21705 emitted here. In neither circumstance do we want
21706 import_export_decl to adjust the linkage. */
21708 }
21710 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21711 important template arguments. If any are missing, we check whether
21712 they're important by using error_mark_node for substituting into any
21713 args that were used for partial ordering (the ones between ARGS and END)
21714 and seeing if it bubbles up. */
21716 static bool
21718 {
21723 {
21726 }
21728 {
21732 }
21734 }
21736 /* Given two function templates PAT1 and PAT2, return:
21738 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21739 -1 if PAT2 is more specialized than PAT1.
21740 0 if neither is more specialized.
21742 LEN indicates the number of parameters we should consider
21743 (defaulted parameters should not be considered).
21745 The 1998 std underspecified function template partial ordering, and
21746 DR214 addresses the issue. We take pairs of arguments, one from
21747 each of the templates, and deduce them against each other. One of
21748 the templates will be more specialized if all the *other*
21749 template's arguments deduce against its arguments and at least one
21750 of its arguments *does* *not* deduce against the other template's
21751 corresponding argument. Deduction is done as for class templates.
21752 The arguments used in deduction have reference and top level cv
21753 qualifiers removed. Iff both arguments were originally reference
21754 types *and* deduction succeeds in both directions, an lvalue reference
21755 wins against an rvalue reference and otherwise the template
21756 with the more cv-qualified argument wins for that pairing (if
21757 neither is more cv-qualified, they both are equal). Unlike regular
21758 deduction, after all the arguments have been deduced in this way,
21759 we do *not* verify the deduced template argument values can be
21760 substituted into non-deduced contexts.
21762 The logic can be a bit confusing here, because we look at deduce1 and
21763 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21764 can find template arguments for pat1 to make arg1 look like arg2, that
21765 means that arg2 is at least as specialized as arg1. */
21767 int
21769 {
21782 /* Remove the this parameter from non-static member functions. If
21783 one is a non-static member function and the other is not a static
21784 member function, remove the first parameter from that function
21785 also. This situation occurs for operator functions where we
21786 locate both a member function (with this pointer) and non-member
21787 operator (with explicit first operand). */
21789 {
21794 }
21796 {
21799 {
21800 len--;
21802 }
21803 }
21805 /* If only one is a conversion operator, they are unordered. */
21809 /* Consider the return type for a conversion function */
21811 {
21814 len++;
21815 }
21817 processing_template_decl++;
21823 /* Stop when an ellipsis is seen. */
21825 {
21836 {
21837 /* When both arguments are pack expansions, we need only
21838 unify the patterns themselves. */
21842 /* This is the last comparison we need to do. */
21844 }
21846 /* DR 1847: If a particular P contains no template-parameters that
21847 participate in template argument deduction, that P is not used to
21848 determine the ordering. */
21854 {
21858 }
21861 {
21865 }
21871 {
21877 /* Setup the parameter vector, which contains only ARG1. */
21880 /* Setup the argument vector, which contains the remaining
21881 arguments. */
21890 /* We cannot deduce in the other direction, because ARG1 is
21891 a pack expansion but ARG2 is not. */
21893 }
21895 {
21901 /* Setup the parameter vector, which contains only ARG1. */
21904 /* Setup the argument vector, which contains the remaining
21905 arguments. */
21914 /* We cannot deduce in the other direction, because ARG2 is
21915 a pack expansion but ARG1 is not.*/
21917 }
21919 else
21920 {
21921 /* The normal case, where neither argument is a pack
21922 expansion. */
21929 }
21931 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21932 arg2, then arg2 is not as specialized as arg1. */
21938 /* "If, for a given type, deduction succeeds in both directions
21939 (i.e., the types are identical after the transformations above)
21940 and both P and A were reference types (before being replaced with
21941 the type referred to above):
21942 - if the type from the argument template was an lvalue reference and
21943 the type from the parameter template was not, the argument type is
21944 considered to be more specialized than the other; otherwise,
21945 - if the type from the argument template is more cv-qualified
21946 than the type from the parameter template (as described above),
21947 the argument type is considered to be more specialized than the other;
21948 otherwise,
21949 - neither type is more specialized than the other." */
21952 {
21954 {
21957 else
21959 }
21961 {
21966 }
21967 }
21970 /* We've failed to deduce something in either direction.
21971 These must be unordered. */
21974 next:
21978 /* We have already processed all of the arguments in our
21979 handing of the pack expansion type. */
21984 }
21986 /* "In most cases, all template parameters must have values in order for
21987 deduction to succeed, but for partial ordering purposes a template
21988 parameter may remain without a value provided it is not used in the
21989 types being used for partial ordering."
21991 Thus, if we are missing any of the targs1 we need to substitute into
21992 origs1, then pat2 is not as specialized as pat1. This can happen when
21993 there is a nondeduced context. */
21999 processing_template_decl--;
22001 /* If both deductions succeed, the partial ordering selects the more
22002 constrained template. */
22004 {
22009 }
22011 /* All things being equal, if the next argument is a pack expansion
22012 for one function but not for the other, prefer the
22013 non-variadic function. FIXME this is bogus; see c++/41958. */
22017 {
22020 }
22026 else
22028 }
22030 /* Determine which of two partial specializations of TMPL is more
22031 specialized.
22033 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22034 to the first partial specialization. The TREE_PURPOSE is the
22035 innermost set of template parameters for the partial
22036 specialization. PAT2 is similar, but for the second template.
22038 Return 1 if the first partial specialization is more specialized;
22039 -1 if the second is more specialized; 0 if neither is more
22040 specialized.
22042 See [temp.class.order] for information about determining which of
22043 two templates is more specialized. */
22045 static int
22047 {
22048 tree targs;
22057 /* Just like what happens for functions, if we are ordering between
22058 different template specializations, we may encounter dependent
22059 types in the arguments, and we need our dependency check functions
22060 to behave correctly. */
22064 {
22067 }
22071 {
22074 }
22077 /* If both deductions succeed, the partial ordering selects the more
22078 constrained template. */
22082 /* In the case of a tie where at least one of the templates
22083 has a parameter pack at the end, the template with the most
22084 non-packed parameters wins. */
22086 && any_deductions
22089 {
22095 /* We don't count the pack expansion at the end. */
22105 }
22108 }
22110 /* Return the template arguments that will produce the function signature
22111 DECL from the function template FN, with the explicit template
22112 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22113 also match. Return NULL_TREE if no satisfactory arguments could be
22114 found. */
22116 static tree
22118 {
22122 tree decl_arg_types;
22125 tree arg;
22129 /* Never do unification on the 'this' parameter. */
22150 }
22152 /* Return the innermost template arguments that, when applied to a partial
22153 specialization SPEC_TMPL of TMPL, yield the ARGS.
22155 For example, suppose we have:
22157 template <class T, class U> struct S {};
22158 template <class T> struct S<T*, int> {};
22160 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22161 partial specialization and the ARGS will be {double*, int}. The resulting
22162 vector will be {double}, indicating that `T' is bound to `double'. */
22164 static tree
22166 {
22168 tree spec_args
22171 tree deduced_args;
22172 tree innermost_deduced_args;
22176 {
22180 innermost_deduced_args);
22181 }
22182 else
22186 again:
22195 {
22197 {
22203 }
22205 }
22209 {
22212 }
22214 /* Verify that nondeduced template arguments agree with the type
22215 obtained from argument deduction.
22217 For example:
22219 struct A { typedef int X; };
22220 template <class T, class U> struct C {};
22221 template <class T> struct C<T, typename T::X> {};
22223 Then with the instantiation `C<A, int>', we can deduce that
22224 `T' is `A' but unify () does not check whether `typename T::X'
22225 is `int'. */
22236 /* We only need to check the innermost arguments; the other
22237 arguments will always agree. */
22242 /* Now that we have bindings for all of the template arguments,
22243 ensure that the arguments deduced for the template template
22244 parameters have compatible template parameter lists. See the use
22245 of template_template_parm_bindings_ok_p in fn_type_unification
22246 for more information. */
22251 }
22253 // Compare two function templates T1 and T2 by deducing bindings
22254 // from one against the other. If both deductions succeed, compare
22255 // constraints to see which is more constrained.
22256 static int
22258 {
22263 {
22266 }
22269 {
22272 }
22274 // If both deductions succeed, then one may be more constrained.
22279 }
22281 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22282 Return the TREE_LIST node with the most specialized template, if
22283 any. If there is no most specialized template, the error_mark_node
22284 is returned.
22286 Note that this function does not look at, or modify, the
22287 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22288 returned is one of the elements of INSTANTIATIONS, callers may
22289 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22290 and retrieve it from the value returned. */
22292 tree
22294 {
22301 {
22307 {
22308 /* Equally specialized, move to next function. If there
22309 is no next function, nothing's most specialized. */
22314 }
22315 }
22318 /* Now verify that champ is better than everything earlier in the
22319 instantiation list. */
22322 {
22325 }
22326 }
22328 processing_template_decl--;
22334 }
22336 /* If DECL is a specialization of some template, return the most
22337 general such template. Otherwise, returns NULL_TREE.
22339 For example, given:
22341 template <class T> struct S { template <class U> void f(U); };
22343 if TMPL is `template <class U> void S<int>::f(U)' this will return
22344 the full template. This function will not trace past partial
22345 specializations, however. For example, given in addition:
22347 template <class T> struct S<T*> { template <class U> void f(U); };
22349 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22350 `template <class T> template <class U> S<T*>::f(U)'. */
22352 tree
22354 {
22356 {
22359 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22360 template friend, or a FIELD_DECL for a capture pack. */
22363 }
22365 /* Look for more and more general templates. */
22367 {
22368 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22369 (See cp-tree.h for details.) */
22378 /* Stop if we run into an explicitly specialized class template. */
22385 }
22388 }
22390 /* Return the most specialized of the template partial specializations
22391 which can produce TARGET, a specialization of some class or variable
22392 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22393 a TEMPLATE_DECL node corresponding to the partial specialization, while
22394 the TREE_PURPOSE is the set of template arguments that must be
22395 substituted into the template pattern in order to generate TARGET.
22397 If the choice of partial specialization is ambiguous, a diagnostic
22398 is issued, and the error_mark_node is returned. If there are no
22399 partial specializations matching TARGET, then NULL_TREE is
22400 returned, indicating that the primary template should be used. */
22402 static tree
22404 {
22406 tree t;
22407 tree champ;
22414 {
22418 }
22420 {
22423 }
22425 {
22429 }
22430 else
22435 /* For determining which partial specialization to use, only the
22436 innermost args are interesting. */
22438 {
22441 }
22444 {
22445 tree spec_args;
22449 {
22450 /* Substitute in the template args from the enclosing class. */
22454 }
22461 {
22465 /* Keep the candidate only if the constraints are satisfied,
22466 or if we're not compiling with concepts. */
22469 {
22472 }
22473 }
22474 }
22484 {
22487 ;
22488 else
22489 {
22491 {
22494 {
22497 }
22498 }
22500 }
22501 }
22505 {
22508 {
22511 }
22512 }
22515 {
22522 else
22526 {
22531 }
22534 }
22537 }
22539 /* Explicitly instantiate DECL. */
22541 void
22543 {
22548 /* An error occurred, for which grokdeclarator has already issued
22549 an appropriate message. */
22552 {
22555 }
22561 {
22562 /* There is an asymmetry here in the way VAR_DECLs and
22563 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22564 the latter, the DECL we get back will be marked as a
22565 template instantiation, and the appropriate
22566 DECL_TEMPLATE_INFO will be set up. This does not happen for
22567 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22568 should handle VAR_DECLs as it currently handles
22569 FUNCTION_DECLs. */
22571 {
22574 }
22577 {
22580 }
22582 {
22587 }
22588 }
22590 {
22593 }
22594 else
22597 /* Check for various error cases. Note that if the explicit
22598 instantiation is valid the RESULT will currently be marked as an
22599 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22600 until we get here. */
22603 {
22604 /* DR 259 [temp.spec].
22606 Both an explicit instantiation and a declaration of an explicit
22607 specialization shall not appear in a program unless the explicit
22608 instantiation follows a declaration of the explicit specialization.
22610 For a given set of template parameters, if an explicit
22611 instantiation of a template appears after a declaration of an
22612 explicit specialization for that template, the explicit
22613 instantiation has no effect. */
22615 }
22617 {
22618 /* [temp.spec]
22620 No program shall explicitly instantiate any template more
22621 than once.
22623 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22624 the first instantiation was `extern' and the second is not,
22625 and EXTERN_P for the opposite case. */
22628 /* If an "extern" explicit instantiation follows an ordinary
22629 explicit instantiation, the template is instantiated. */
22632 }
22634 {
22637 }
22639 {
22642 }
22645 ;
22647 {
22650 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22653 }
22654 else
22662 }
22664 static void
22666 {
22672 {
22675 }
22676 }
22678 /* Called from do_type_instantiation through binding_table_foreach to
22679 do recursive instantiation for the type bound in ENTRY. */
22680 static void
22682 {
22688 }
22690 /* Perform an explicit instantiation of template class T. STORAGE, if
22691 non-null, is the RID for extern, inline or static. COMPLAIN is
22692 nonzero if this is called from the parser, zero if called recursively,
22693 since the standard is unclear (as detailed below). */
22695 void
22697 {
22707 {
22708 tree tmpl =
22712 else
22715 }
22720 {
22723 t);
22725 }
22728 {
22730 {
22732 {
22735 "ISO C++ 1998 forbids the use of %<extern%> on "
22737 }
22738 else
22740 "ISO C++ forbids the use of %qE"
22742 }
22750 else
22751 {
22753 storage);
22755 }
22756 }
22759 {
22760 /* DR 259 [temp.spec].
22762 Both an explicit instantiation and a declaration of an explicit
22763 specialization shall not appear in a program unless the explicit
22764 instantiation follows a declaration of the explicit specialization.
22766 For a given set of template parameters, if an explicit
22767 instantiation of a template appears after a declaration of an
22768 explicit specialization for that template, the explicit
22769 instantiation has no effect. */
22771 }
22773 {
22774 /* [temp.spec]
22776 No program shall explicitly instantiate any template more
22777 than once.
22779 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22780 instantiation was `extern'. If EXTERN_P then the second is.
22781 These cases are OK. */
22788 /* If we've already instantiated the template, just return now. */
22791 }
22799 /* In contrast to implicit instantiation, where only the
22800 declarations, and not the definitions, of members are
22801 instantiated, we have here:
22803 [temp.explicit]
22805 The explicit instantiation of a class template specialization
22806 implies the instantiation of all of its members not
22807 previously explicitly specialized in the translation unit
22808 containing the explicit instantiation.
22810 Of course, we can't instantiate member template classes, since we
22811 don't have any arguments for them. Note that the standard is
22812 unclear on whether the instantiation of the members are
22813 *explicit* instantiations or not. However, the most natural
22814 interpretation is that it should be an explicit
22815 instantiation. */
22819 && !static_p
22822 {
22827 }
22832 }
22834 /* Given a function DECL, which is a specialization of TMPL, modify
22835 DECL to be a re-instantiation of TMPL with the same template
22836 arguments. TMPL should be the template into which tsubst'ing
22837 should occur for DECL, not the most general template.
22839 One reason for doing this is a scenario like this:
22841 template <class T>
22842 void f(const T&, int i);
22844 void g() { f(3, 7); }
22846 template <class T>
22847 void f(const T& t, const int i) { }
22849 Note that when the template is first instantiated, with
22850 instantiate_template, the resulting DECL will have no name for the
22851 first parameter, and the wrong type for the second. So, when we go
22852 to instantiate the DECL, we regenerate it. */
22854 static void
22856 {
22857 /* The arguments used to instantiate DECL, from the most general
22858 template. */
22859 tree code_pattern;
22863 /* Make sure that we can see identifiers, and compute access
22864 correctly. */
22868 {
22869 tree decl_parm;
22870 tree pattern_parm;
22871 tree specs;
22885 specs);
22887 /* Merge parameter declarations. */
22890 pattern_parm
22894 {
22895 tree parm_type;
22896 tree attributes;
22901 NULL_TREE);
22907 {
22910 }
22913 }
22914 /* Merge any parameters that match with the function parameter
22915 pack. */
22917 {
22919 tree expanded_types;
22920 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22921 the parameters in this function parameter pack. */
22926 {
22927 tree parm_type;
22928 tree attributes;
22931 /* Rename the parameter to include the index. */
22940 {
22943 }
22945 }
22946 }
22947 /* Merge additional specifiers from the CODE_PATTERN. */
22951 }
22953 {
22963 }
22964 else
22968 }
22970 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22971 substituted to get DECL. */
22973 tree
22975 {
22978 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22979 for the instantiation. This is not always the most general
22980 template. Consider, for example:
22982 template <class T>
22983 struct S { template <class U> void f();
22984 template <> void f<int>(); };
22986 and an instantiation of S<double>::f<int>. We want TD to be the
22987 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22989 more general template. */
22991 /* We must also deal with friend templates. Given:
22993 template <class T> struct S {
22994 template <class U> friend void f() {};
22995 };
22997 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22998 so far as the language is concerned, but that's still
22999 where we get the pattern for the instantiation from. On
23000 other hand, if the definition comes outside the class, say:
23002 template <class T> struct S {
23003 template <class U> friend void f();
23004 };
23005 template <class U> friend void f() {}
23007 we don't need to look any further. That's what the check for
23008 DECL_INITIAL is for. */
23012 {
23013 /* The present template, TD, should not be a definition. If it
23014 were a definition, we should be using it! Note that we
23015 cannot restructure the loop to just keep going until we find
23016 a template with a definition, since that might go too far if
23017 a specialization was declared, but not defined. */
23019 /* Fetch the more general template. */
23021 }
23024 }
23026 /* Returns true if we need to instantiate this template instance even if we
23027 know we aren't going to emit it. */
23029 bool
23031 {
23032 /* We always instantiate inline functions so that we can inline them. An
23033 explicit instantiation declaration prohibits implicit instantiation of
23034 non-inline functions. With high levels of optimization, we would
23035 normally inline non-inline functions -- but we're not allowed to do
23036 that for "extern template" functions. Therefore, we check
23037 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23041 /* And we need to instantiate static data members so that
23042 their initializers are available in integral constant
23043 expressions. */
23046 }
23048 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23049 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23050 error, true otherwise. */
23052 bool
23054 {
23057 /* Don't instantiate a noexcept-specification from template context. */
23072 {
23078 {
23079 /* If hash_set::add returns true, the element was already there. */
23084 fn);
23086 }
23088 {
23103 }
23104 else
23114 }
23117 {
23120 else
23122 }
23125 }
23127 /* We're starting to process the function INST, an instantiation of PATTERN;
23128 add their parameters to local_specializations. */
23130 static void
23132 {
23136 {
23140 }
23142 {
23144 {
23147 }
23148 else
23149 {
23150 /* Register the (value) argument pack as a specialization of
23151 TMPL_PARM, then move on. */
23154 }
23155 }
23157 }
23159 /* Produce the definition of D, a _DECL generated from a template. If
23160 DEFER_OK is true, then we don't have to actually do the
23161 instantiation now; we just have to do it sometime. Normally it is
23162 an error if this is an explicit instantiation but D is undefined.
23163 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23164 instantiated class template. */
23166 tree
23168 {
23170 tree gen_args;
23171 tree args;
23172 tree td;
23173 tree code_pattern;
23174 tree spec;
23175 tree gen_tmpl;
23183 /* This function should only be used to instantiate templates for
23184 functions and static member variables. */
23187 /* A concept is never instantiated. */
23190 /* Variables are never deferred; if instantiation is required, they
23191 are instantiated right away. That allows for better code in the
23192 case that an expression refers to the value of the variable --
23193 if the variable has a constant value the referring expression can
23194 take advantage of that fact. */
23198 /* Don't instantiate cloned functions. Instead, instantiate the
23199 functions they cloned. */
23207 /* D has already been instantiated or explicitly specialized, so
23208 there's nothing for us to do here.
23210 It might seem reasonable to check whether or not D is an explicit
23211 instantiation, and, if so, stop here. But when an explicit
23212 instantiation is deferred until the end of the compilation,
23213 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23214 the instantiation. */
23217 /* Check to see whether we know that this template will be
23218 instantiated in some other file, as with "extern template"
23219 extension. */
23222 /* In general, we do not instantiate such templates. */
23230 /* We should already have the extra args. */
23233 /* And what's in the hash table should match D. */
23237 /* This needs to happen before any tsubsting. */
23243 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23244 for the instantiation. */
23249 {
23250 /* Look up an explicit specialization, if any. */
23254 {
23257 }
23258 }
23262 /* We should never be trying to instantiate a member of a class
23263 template or partial specialization. */
23268 /* In the case of a friend template whose definition is provided
23269 outside the class, we may have too many arguments. Drop the
23270 ones we don't need. The same is true for specializations. */
23271 args = get_innermost_template_args
23275 {
23281 }
23282 else
23283 {
23288 else
23290 }
23292 /* We may be in the middle of deferred access check. Disable it now. */
23295 /* Unless an explicit instantiation directive has already determined
23296 the linkage of D, remember that a definition is available for
23297 this entity. */
23307 /* If D is a member of an explicitly instantiated class template,
23308 and no definition is available, treat it like an implicit
23309 instantiation. */
23312 {
23313 /* Leave linkage flags alone on instantiations with anonymous
23314 visibility. */
23316 {
23319 }
23321 }
23323 /* Defer all other templates, unless we have been explicitly
23324 forbidden from doing so. */
23326 template. */
23327 ! pattern_defined
23328 /* If it's OK to postpone instantiation, do so. */
23329 || defer_ok
23330 /* If this is a static data member that will be defined
23331 elsewhere, we don't want to instantiate the entire data
23332 member, but we do want to instantiate the initializer so that
23333 we can substitute that elsewhere. */
23335 /* Handle here a deleted function too, avoid generating
23336 its body (c++/61080). */
23338 {
23339 /* The definition of the static data member is now required so
23340 we must substitute the initializer. */
23344 {
23345 tree ns;
23346 tree init;
23355 args,
23358 /* If instantiating the initializer involved instantiating this
23359 again, don't call cp_finish_decl twice. */
23361 {
23362 /* Make sure the initializer is still constant, in case of
23363 circular dependency (template/instantiate6.C). */
23364 const_init
23368 LOOKUP_ONLYCONVERTING);
23369 }
23373 }
23375 /* We restore the source position here because it's used by
23376 add_pending_template. */
23382 /* [temp.explicit]
23384 The definition of a non-exported function template, a
23385 non-exported member function template, or a non-exported
23386 member function or static data member of a class template
23387 shall be present in every translation unit in which it is
23388 explicitly instantiated. */
23392 /* If we're in unevaluated context, we just wanted to get the
23393 constant value; this isn't an odr use, so don't queue
23394 a full instantiation. */
23397 /* ??? Historically, we have instantiated inline functions, even
23398 when marked as "extern template". */
23402 }
23403 /* Tell the repository that D is available in this translation unit
23404 -- and see if it is supposed to be instantiated here. */
23406 {
23407 /* In a PCH file, despite the fact that the repository hasn't
23408 requested instantiation in the PCH it is still possible that
23409 an instantiation will be required in a file that includes the
23410 PCH. */
23413 /* Instantiate inline functions so that the inliner can do its
23414 job, even though we'll not be emitting a copy of this
23415 function. */
23418 }
23421 tree fn_context;
23432 else
23433 {
23437 }
23439 /* Mark D as instantiated so that recursive calls to
23440 instantiate_decl do not try to instantiate it again. */
23443 /* Regenerate the declaration in case the template has been modified
23444 by a subsequent redeclaration. */
23447 /* We already set the file and line above. Reset them now in case
23448 they changed as a result of calling regenerate_decl_from_template. */
23452 {
23453 tree init;
23456 /* Clear out DECL_RTL; whatever was there before may not be right
23457 since we've reset the type of the declaration. */
23461 /* The initializer is placed in DECL_INITIAL by
23462 regenerate_decl_from_template so we don't need to
23463 push/pop_access_scope again here. Pull it out so that
23464 cp_finish_decl can process it. */
23469 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23470 initializer. That function will defer actual emission until
23471 we have a chance to determine linkage. */
23474 /* Enter the scope of D so that access-checking works correctly. */
23487 }
23491 {
23492 /* Set up the list of local specializations. */
23496 /* Set up context. */
23500 else
23503 /* Some typedefs referenced from within the template code need to be
23504 access checked at template instantiation time, i.e now. These
23505 types were added to the template at parsing time. Let's get those
23506 and perform the access checks then. */
23508 args);
23510 /* Create substitution entries for the parameters. */
23513 /* Substitute into the body of the function. */
23517 else
23518 {
23523 /* Set the current input_location to the end of the function
23524 so that finish_function knows where we are. */
23525 input_location
23528 /* Remember if we saw an infinite loop in the template. */
23529 current_function_infinite_loop
23531 }
23533 /* Finish the function. */
23537 else
23538 {
23541 }
23545 }
23547 /* We're not deferring instantiation any more. */
23552 else
23558 out:
23567 }
23569 /* Run through the list of templates that we wish we could
23570 instantiate, and instantiate any we can. RETRIES is the
23571 number of times we retry pending template instantiation. */
23573 void
23575 {
23579 /* Instantiating templates may trigger vtable generation. This in turn
23580 may require further template instantiations. We place a limit here
23581 to avoid infinite loop. */
23583 {
23587 "template instantiation depth exceeds maximum of %d"
23588 " instantiating %q+D, possibly from virtual table generation"
23592 /* Pretend that we defined it. */
23595 }
23597 do
23598 {
23603 {
23608 {
23610 {
23625 }
23628 }
23629 else
23630 {
23633 {
23634 instantiation
23640 }
23644 }
23647 /* If INSTANTIATION has been instantiated, then we don't
23648 need to consider it again in the future. */
23650 else
23651 {
23654 }
23657 }
23659 }
23663 }
23665 /* Substitute ARGVEC into T, which is a list of initializers for
23666 either base class or a non-static data member. The TREE_PURPOSEs
23667 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23668 instantiate_decl. */
23670 static tree
23672 {
23677 {
23678 tree decl;
23679 tree init;
23685 {
23686 tree expr;
23687 tree arg;
23689 /* Expand the base class expansion type into separate base
23690 classes. */
23692 tf_warning_or_error,
23693 NULL_TREE);
23697 /* We'll be building separate TREE_LISTs of arguments for
23698 each base. */
23704 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23705 expand each argument in the TREE_VALUE of t. */
23712 /* VOID_TYPE_NODE is used to indicate
23713 value-initialization. */
23714 {
23717 }
23718 else
23719 {
23720 /* Substitute parameter packs into each argument in the
23721 TREE_LIST. */
23724 {
23725 tree expanded_exprs;
23727 /* Expand the argument. */
23729 expanded_exprs
23731 tf_warning_or_error,
23732 NULL_TREE);
23736 /* Prepend each of the expanded expressions to the
23737 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23739 {
23744 }
23745 }
23748 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23749 since we built them backwards. */
23751 {
23754 }
23755 }
23756 }
23759 {
23761 {
23765 }
23766 else
23767 {
23768 tree tmp;
23783 /* If we had an initializer but it instantiated to nothing,
23784 value-initialize the object. This will only occur when
23785 the initializer was a pack expansion where the parameter
23786 packs used in that expansion were of length zero. */
23789 }
23793 {
23795 decl);
23797 }
23798 /* Look for a target constructor. */
23802 {
23805 {
23809 }
23811 }
23814 {
23818 }
23819 }
23820 }
23822 }
23824 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23826 static void
23828 {
23833 else
23835 }
23837 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23838 is the instantiation (which should have been created with
23839 start_enum) and ARGS are the template arguments to use. */
23841 static void
23843 {
23844 tree e;
23850 {
23851 tree value;
23852 tree decl;
23855 /* Note that in a template enum, the TREE_VALUE is the
23856 CONST_DECL, not the corresponding INTEGER_CST. */
23861 /* Give this enumeration constant the correct access. */
23864 /* Actually build the enumerator itself. Here we're assuming that
23865 enumerators can't have dependent attributes. */
23868 }
23878 }
23880 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23881 its type -- but without substituting the innermost set of template
23882 arguments. So, innermost set of template parameters will appear in
23883 the type. */
23885 tree
23887 {
23888 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23890 }
23892 /* Return truthvalue if we're processing a template different from
23893 the last one involved in diagnostics. */
23894 bool
23896 {
23898 }
23900 /* Remember current template involved in diagnostics. */
23901 void
23903 {
23905 }
23909 {
23911 }
23913 /* Return TRUE if current_function_decl is being instantiated, false
23914 otherwise. */
23916 bool
23918 {
23921 }
23923 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23924 type. Return false for ok, true for disallowed. Issue error and
23925 inform messages under control of COMPLAIN. */
23927 static bool
23929 {
23944 /* A bound template template parm could later be instantiated to have a valid
23945 nontype parm type via an alias template. */
23951 {
23954 else
23956 type);
23957 }
23959 }
23961 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23962 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23964 static bool
23966 {
23967 tree scope;
23969 /* [temp.dep.type]
23971 A type is dependent if it is:
23973 -- a template parameter. Template template parameters are types
23974 for us (since TYPE_P holds true for them) so we handle
23975 them here. */
23979 /* -- a qualified-id with a nested-name-specifier which contains a
23980 class-name that names a dependent type or whose unqualified-id
23981 names a dependent type. */
23985 /* An alias template specialization can be dependent even if the
23986 resulting type is not. */
23990 /* -- a cv-qualified type where the cv-unqualified type is
23991 dependent.
23992 No code is necessary for this bullet; the code below handles
23993 cv-qualified types, and we don't want to strip aliases with
23994 TYPE_MAIN_VARIANT because of DR 1558. */
23995 /* -- a compound type constructed from any dependent type. */
24005 {
24006 tree arg_type;
24011 arg_type;
24016 /* A value-dependent noexcept-specifier makes the type dependent. */
24019 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24020 affect overload resolution and treating it as dependent breaks
24021 things. */
24026 }
24027 /* -- an array type constructed from any dependent type or whose
24028 size is specified by a constant expression that is
24029 value-dependent.
24031 We checked for type- and value-dependence of the bounds in
24032 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24034 {
24039 }
24041 /* -- a template-id in which either the template name is a template
24042 parameter ... */
24045 /* ... or any of the template arguments is a dependent type or
24046 an expression that is type-dependent or value-dependent. */
24048 && (any_dependent_template_arguments_p
24052 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24053 dependent; if the argument of the `typeof' expression is not
24054 type-dependent, then it should already been have resolved. */
24060 /* A template argument pack is dependent if any of its packed
24061 arguments are. */
24063 {
24069 }
24071 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24072 be template parameters. */
24079 /* The standard does not specifically mention types that are local
24080 to template functions or local classes, but they should be
24081 considered dependent too. For example:
24083 template <int I> void f() {
24084 enum E { a = I };
24085 S<sizeof (E)> s;
24086 }
24088 The size of `E' cannot be known until the value of `I' has been
24089 determined. Therefore, `E' must be considered dependent. */
24093 /* Don't use type_dependent_expression_p here, as it can lead
24094 to infinite recursion trying to determine whether a lambda
24095 nested in a lambda is dependent (c++/47687). */
24099 && (any_dependent_template_arguments_p
24103 /* Other types are non-dependent. */
24105 }
24107 /* Returns TRUE if TYPE is dependent, in the sense of
24108 [temp.dep.type]. Note that a NULL type is considered dependent. */
24110 bool
24112 {
24113 /* If there are no template parameters in scope, then there can't be
24114 any dependent types. */
24116 {
24117 /* If we are not processing a template, then nobody should be
24118 providing us with a dependent type. */
24122 }
24124 /* If the type is NULL, we have not computed a type for the entity
24125 in question; in that case, the type is dependent. */
24129 /* Erroneous types can be considered non-dependent. */
24133 /* Getting here with global_type_node means we improperly called this
24134 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24137 /* If we have not already computed the appropriate value for TYPE,
24138 do so now. */
24140 {
24143 }
24146 }
24148 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24149 lookup. In other words, a dependent type that is not the current
24150 instantiation. */
24152 bool
24154 {
24157 }
24159 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24160 an unknown base of 'this' (and is therefore instantiation-dependent). */
24162 static bool
24164 {
24181 }
24183 /* T is a SCOPE_REF; return whether we need to consider it
24184 instantiation-dependent so that we can check access at instantiation
24185 time even though we know which member it resolves to. */
24187 static bool
24189 {
24196 else
24198 }
24200 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24201 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24202 expression. */
24204 /* Note that this predicate is not appropriate for general expressions;
24205 only constant expressions (that satisfy potential_constant_expression)
24206 can be tested for value dependence. */
24208 bool
24210 {
24214 /* A type-dependent expression is also value-dependent. */
24219 {
24221 /* A dependent member function of the current instantiation. */
24225 /* A dependent member function of the current instantiation. */
24232 /* A name that has not been looked up -- must be dependent. */
24236 /* A non-type template parm. */
24240 /* A non-type template parm. */
24246 /* A constant with literal type and is initialized
24247 with an expression that is value-dependent. */
24249 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24253 {
24257 }
24266 /* These expressions are value-dependent if the type to which
24267 the cast occurs is dependent or the expression being casted
24268 is value-dependent. */
24269 {
24275 /* A functional cast has a list of operands. */
24278 {
24279 /* If there are no operands, it must be an expression such
24280 as "int()". This should not happen for aggregate types
24281 because it would form non-constant expressions. */
24286 }
24292 }
24297 /* FALLTHRU */
24300 /* A `sizeof' expression is value-dependent if the operand is
24301 type-dependent or is a pack expansion. */
24310 /* An 'encode' expression is value-dependent if the operand is
24311 type-dependent. */
24320 /* All instantiation-dependent expressions should also be considered
24321 value-dependent. */
24329 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24330 is value-dependent. */
24331 {
24340 }
24343 {
24360 }
24371 {
24375 }
24378 /* Treat all requires-expressions as value-dependent so
24379 we don't try to fold them. */
24386 {
24393 {
24395 /* In a call to a constexpr member function, look through the
24396 implicit ADDR_EXPR on the object argument so that it doesn't
24397 cause the call to be considered value-dependent. We also
24398 look through it in potential_constant_expression. */
24405 }
24407 }
24413 {
24415 tree val;
24422 }
24425 /* Treat a GNU statement expression as dependent to avoid crashing
24426 under instantiate_non_dependent_expr; it can't be constant. */
24430 /* A constant expression is value-dependent if any subexpression is
24431 value-dependent. */
24433 {
24440 {
24444 {
24447 /* In some cases, some of the operands may be missing.
24448 (For example, in the case of PREDECREMENT_EXPR, the
24449 amount to increment by may be missing.) That doesn't
24450 make the expression dependent. */
24453 }
24454 }
24458 }
24460 }
24462 /* The expression is not value-dependent. */
24464 }
24466 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24467 [temp.dep.expr]. Note that an expression with no type is
24468 considered dependent. Other parts of the compiler arrange for an
24469 expression with type-dependent subexpressions to have no type, so
24470 this function doesn't have to be fully recursive. */
24472 bool
24474 {
24483 /* An unresolved name is always dependent. */
24489 /* A fold expression is type-dependent. */
24496 /* Some expression forms are never type-dependent. */
24510 /* The types of these expressions depends only on the type to which
24511 the cast occurs. */
24520 /* The types of these expressions depends only on the type created
24521 by the expression. */
24524 {
24525 /* For NEW_EXPR tree nodes created inside a template, either
24526 the object type itself or a TREE_LIST may appear as the
24527 operand 1. */
24530 /* This is an array type. We need to check array dimensions
24531 as well. */
24533 || value_dependent_expression_p
24535 else
24537 }
24540 {
24544 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24545 contains an identifier associated by name lookup with one or more
24546 declarations declared with a dependent type, or...a
24547 nested-name-specifier or qualified-id that names a member of an
24548 unknown specialization. */
24551 }
24561 {
24562 tree elt;
24566 {
24569 }
24571 }
24573 /* A static data member of the current instantiation with incomplete
24574 array type is type-dependent, as the definition and specializations
24575 can have different bounds. */
24582 /* An array of unknown bound depending on a variadic parameter, eg:
24584 template<typename... Args>
24585 void foo (Args... args)
24586 {
24587 int arr[] = { args... };
24588 }
24590 template<int... vals>
24591 void bar ()
24592 {
24593 int arr[] = { vals... };
24594 }
24596 If the array has no length and has an initializer, it must be that
24597 we couldn't determine its length in cp_complete_array_type because
24598 it is dependent. */
24606 /* A function or variable template-id is type-dependent if it has any
24607 dependent template arguments. */
24611 {
24612 /* Consider the innermost template arguments, since those are the ones
24613 that come from the template-id; the template arguments for the
24614 enclosing class do not make it type-dependent unless they are used in
24615 the type of the decl. */
24617 && (any_dependent_template_arguments_p
24620 }
24622 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24623 type-dependent. Checking this is important for functions with auto return
24624 type, which looks like a dependent type. */
24632 {
24636 }
24638 /* Always dependent, on the number of arguments if nothing else. */
24643 {
24648 {
24654 }
24655 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24660 {
24665 }
24668 {
24675 }
24685 }
24689 /* Dependent type attributes might not have made it from the decl to
24690 the type yet. */
24696 }
24698 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24699 type-dependent if the expression refers to a member of the current
24700 instantiation and the type of the referenced member is dependent, or the
24701 class member access expression refers to a member of an unknown
24702 specialization.
24704 This function returns true if the OBJECT in such a class member access
24705 expression is of an unknown specialization. */
24707 bool
24709 {
24710 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24711 dependent. */
24716 }
24718 /* walk_tree callback function for instantiation_dependent_expression_p,
24719 below. Returns non-zero if a dependent subexpression is found. */
24721 static tree
24724 {
24726 {
24727 /* We don't have to worry about decltype currently because decltype
24728 of an instantiation-dependent expr is a dependent type. This
24729 might change depending on the resolution of DR 1172. */
24732 }
24735 {
24736 /* Don't treat an argument list as dependent just because it has no
24737 TREE_TYPE. */
24745 /* Handle expressions with type operands. */
24750 {
24755 {
24758 else
24759 {
24762 }
24763 }
24765 }
24769 /* In a template, finish_class_member_access_expr creates a
24770 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24771 type-dependent, so that we can check access control at
24772 instantiation time (PR 42277). See also Core issue 1273. */
24779 else
24782 /* Treat statement-expressions as dependent. */
24786 /* Treat requires-expressions as dependent. */
24791 /* Treat calls to function concepts as dependent. */
24797 /* And variable concepts. */
24804 }
24808 else
24810 }
24812 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24813 sense defined by the ABI:
24815 "An expression is instantiation-dependent if it is type-dependent
24816 or value-dependent, or it has a subexpression that is type-dependent
24817 or value-dependent."
24819 Except don't actually check value-dependence for unevaluated expressions,
24820 because in sizeof(i) we don't care about the value of i. Checking
24821 type-dependence will in turn check value-dependence of array bounds/template
24822 arguments as needed. */
24824 bool
24826 {
24827 tree result;
24838 }
24840 /* As above, but also check value-dependence of the expression as a whole. */
24842 bool
24844 {
24847 }
24849 /* Like type_dependent_expression_p, but it also works while not processing
24850 a template definition, i.e. during substitution or mangling. */
24852 bool
24854 {
24860 }
24862 /* Returns TRUE if ARGS contains a type-dependent expression. */
24864 bool
24866 {
24868 tree arg;
24871 {
24874 }
24876 }
24878 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24879 expressions) contains any type-dependent expressions. */
24881 bool
24883 {
24889 }
24891 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24892 expressions) contains any value-dependent expressions. */
24894 bool
24896 {
24902 }
24904 /* Returns TRUE if the ARG (a template argument) is dependent. */
24906 bool
24908 {
24912 /* Assume a template argument that was wrongly written by the user
24913 is dependent. This is consistent with what
24914 any_dependent_template_arguments_p [that calls this function]
24915 does. */
24925 {
24928 /* A member template of a dependent class is not necessarily
24929 type-dependent, but it is a dependent template argument because it
24930 will be a member of an unknown specialization to that template. */
24933 }
24935 {
24939 {
24942 }
24945 }
24948 else
24951 }
24953 /* Returns true if ARGS (a collection of template arguments) contains
24954 any types that require structural equality testing. */
24956 bool
24958 {
24968 {
24971 {
24977 {
24978 /* Look inside the argument pack. */
24981 }
24984 {
24997 }
24998 }
24999 }
25002 }
25004 /* Returns true if ARGS (a collection of template arguments) contains
25005 any dependent arguments. */
25007 bool
25009 {
25019 {
25024 }
25027 }
25029 /* Returns TRUE if the template TMPL is type-dependent. */
25031 bool
25033 {
25035 {
25040 }
25042 /* Template template parameters are dependent. */
25046 /* So are names that have not been looked up. */
25050 }
25052 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25054 bool
25056 {
25059 }
25061 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25062 are dependent. */
25064 bool
25066 {
25073 {
25095 {
25099 }
25103 {
25107 {
25112 }
25113 }
25114 }
25117 }
25119 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25120 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25121 no such TYPE can be found. Note that this function peers inside
25122 uninstantiated templates and therefore should be used only in
25123 extremely limited situations. ONLY_CURRENT_P restricts this
25124 peering to the currently open classes hierarchy (which is required
25125 when comparing types). */
25127 tree
25129 {
25130 tree scope;
25131 tree name;
25132 tree decl;
25134 tree pushed_scope;
25135 tree result;
25140 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25141 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25142 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25143 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25144 identifier of the TYPENAME_TYPE anymore.
25145 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25146 TYPENAME_TYPE instead, we avoid messing up with a possible
25147 typedef variant case. */
25150 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25151 it first before we can figure out what NAME refers to. */
25153 {
25155 /* Given a class template A with a dependent base with nested type C,
25156 typedef typename A::C::C C will land us here, as trying to resolve
25157 the initial A::C leads to the local C typedef, which leads back to
25158 A::C::C. So we break the recursion now. */
25160 else
25162 }
25163 /* If we don't know what SCOPE refers to, then we cannot resolve the
25164 TYPENAME_TYPE. */
25167 /* If this is a typedef, we don't want to look inside (c++/11987). */
25170 /* If SCOPE isn't the template itself, it will not have a valid
25171 TYPE_FIELDS list. */
25173 /* scope is either the template itself or a compatible instantiation
25174 like X<T>, so look up the name in the original template. */
25176 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25178 /* If scope has no fields, it can't be a current instantiation. Check this
25179 before currently_open_class to avoid infinite recursion (71515). */
25182 /* If the SCOPE is not the current instantiation, there's no reason
25183 to look inside it. */
25186 /* Enter the SCOPE so that name lookup will be resolved as if we
25187 were in the class definition. In particular, SCOPE will no
25188 longer be considered a dependent type. */
25190 /* Look up the declaration. */
25192 tf_warning_or_error);
25196 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25197 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25203 {
25207 }
25210 {
25211 /* Obtain the template and the arguments. */
25214 {
25215 /* We get here with a plain identifier because a previous tentative
25216 parse of the nested-name-specifier as part of a ptr-operator saw
25217 ::template X<A>. The use of ::template is necessary in a
25218 ptr-operator, but wrong in a declarator-id.
25220 [temp.names]: In a qualified-id of a declarator-id, the keyword
25221 template shall not appear at the top level. */
25225 }
25227 /* Instantiate the template. */
25233 }
25235 /* Leave the SCOPE. */
25239 /* If we failed to resolve it, return the original typename. */
25243 /* If lookup found a typename type, resolve that too. */
25245 {
25246 /* Ill-formed programs can cause infinite recursion here, so we
25247 must catch that. */
25251 }
25253 /* Qualify the resulting type. */
25259 }
25261 /* EXPR is an expression which is not type-dependent. Return a proxy
25262 for EXPR that can be used to compute the types of larger
25263 expressions containing EXPR. */
25265 tree
25267 {
25269 tree inner_expr;
25271 /* When checking, try to get a constant value for all non-dependent
25272 expressions in order to expose bugs in *_dependent_expression_p
25273 and constexpr. This can affect code generation, see PR70704, so
25274 only do this for -fchecking=2. */
25277 /* Don't do this during nsdmi parsing as it can lead to
25278 unexpected recursive instantiations. */
25280 /* Don't do this during concept expansion either and for
25281 the same reason. */
25287 /* Preserve OVERLOADs; the functions must be available to resolve
25288 types. */
25299 /* There is no need to return a proxy for a variable. */
25302 /* Preserve string constants; conversions from string constants to
25303 "char *" are allowed, even though normally a "const char *"
25304 cannot be used to initialize a "char *". */
25307 /* Preserve void and arithmetic constants, as an optimization -- there is no
25308 reason to create a new node. */
25313 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25314 There is at least one place where we want to know that a
25315 particular expression is a throw-expression: when checking a ?:
25316 expression, there are special rules if the second or third
25317 argument is a throw-expression. */
25321 /* Don't wrap an initializer list, we need to be able to look inside. */
25325 /* Don't wrap a dummy object, we need to be able to test for it. */
25344 /* If the type is unknown, it can't really be non-dependent */
25347 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25349 }
25351 /* ARGS is a vector of expressions as arguments to a function call.
25352 Replace the arguments with equivalent non-dependent expressions.
25353 This modifies ARGS in place. */
25355 void
25357 {
25359 tree arg;
25362 {
25366 }
25367 }
25369 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25370 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25371 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25373 static tree
25375 {
25389 }
25391 tree
25393 {
25395 }
25397 tree
25399 {
25401 }
25403 /* Return a C++17 deduction placeholder for class template TMPL. */
25405 tree
25407 {
25411 }
25413 /* True iff T is a C++17 class template deduction placeholder. */
25415 bool
25417 {
25419 }
25421 /* Make a "constrained auto" type-specifier. This is an
25422 auto type with constraints that must be associated after
25423 deduction. The constraint is formed from the given
25424 CONC and its optional sequence of arguments, which are
25425 non-null if written as partial-concept-id. */
25427 tree
25429 {
25432 /* Build the constraint. */
25440 /* Our canonical type depends on the constraint. */
25443 /* Attach the constraint to the type declaration. */
25446 }
25448 /* Given type ARG, return std::initializer_list<ARG>. */
25450 static tree
25452 {
25456 {
25460 "deducing from brace-enclosed initializer list"
25464 }
25470 }
25472 /* Replace auto in TYPE with std::initializer_list<auto>. */
25474 static tree
25476 {
25483 }
25485 /* Hash traits for hashing possibly constrained 'auto'
25486 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25489 {
25492 };
25494 /* Hash the 'auto' T. */
25496 inline hashval_t
25498 {
25500 /* Matching constrained-type-specifiers denote the same template
25501 parameter, so hash the constraint. */
25503 else
25504 /* But unconstrained autos are all separate, so just hash the pointer. */
25506 }
25508 /* Compare two 'auto's. */
25512 {
25519 /* Two unconstrained autos are distinct. */
25524 }
25526 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25527 constrained) auto, add it to the vector. */
25529 static int
25531 {
25534 {
25535 /* All the autos were built with index 0; fix that up now. */
25539 /* If this is a repeated constrained-type-specifier, use the index we
25540 chose before. */
25542 else
25543 {
25544 /* Otherwise this is new, so use the current count. */
25547 }
25549 }
25551 /* Always keep walking. */
25553 }
25555 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25556 says they can appear anywhere in the type. */
25558 static tree
25560 {
25569 {
25574 }
25577 }
25579 /* The stem for deduction guide names. */
25582 /* Return the name for a deduction guide for class template TMPL. */
25584 tree
25586 {
25597 }
25599 /* True if NAME is the name of a deduction guide. */
25601 bool
25603 {
25608 }
25610 /* True if FN is a deduction guide. */
25612 bool
25614 {
25619 }
25621 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25623 bool
25625 {
25632 }
25634 /* True if FN is a guide generated from a constructor template. */
25636 bool
25638 {
25646 }
25648 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25649 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25650 template parameter types. Note that the handling of template template
25651 parameters relies on current_template_parms being set appropriately for the
25652 new template. */
25654 static tree
25657 {
25660 tree newtype;
25663 {
25670 }
25671 else
25675 tree newdecl
25680 tree newidx;
25683 {
25693 {
25698 // First create a copy (ttargs) of tsubst_args with an
25699 // additional level for the template template parameter's own
25700 // template parameters (ttparms).
25701 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25709 // Substitute ttargs into ttparms to fix references to
25710 // other template parameters.
25713 // Now substitute again with args based on tparms, to reduce
25714 // the level of the ttparms.
25717 complain);
25718 // Finally, tack the adjusted parms onto tparms.
25720 current_template_parms);
25722 }
25723 }
25724 else
25725 {
25727 tree newconst
25739 }
25742 }
25744 /* Returns a C++17 class deduction guide template based on the constructor
25745 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25746 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25748 static tree
25750 {
25754 location_t loc;
25758 {
25762 {
25765 }
25766 else
25776 }
25777 else
25778 {
25781 fn_tmpl
25791 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25792 fully specialized args for the enclosing class. Strip those off, as
25793 the deduction guide won't have those template parameters. */
25796 /* Discard the 'this' parameter. */
25804 {
25807 /* For a member template constructor, we need to flatten the two
25808 template parameter lists into one, and then adjust the function
25809 signature accordingly. This gets...complicated. */
25812 /* For a member template we should have two levels of parms/args, one
25813 for the class and one for the constructor. We stripped
25814 specialized args for further enclosing classes above. */
25818 /* Template args for translating references to the two-level template
25819 parameters into references to the one-level template parameters we
25820 are creating. */
25825 /* Template parms for the constructor template. */
25828 /* Template parms for the class template. */
25832 /* Template parms for the deduction guide start as a copy of the
25833 template parms for the class. We set current_template_parms for
25834 lookup_template_class_1. */
25840 /* Now we need to rewrite the constructor parms to append them to the
25841 class parms. */
25843 {
25858 }
25860 /* Now we have a final set of template parms to substitute into the
25861 function signature. */
25870 }
25872 }
25875 {
25876 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25880 }
25884 FUNCTION_DECL,
25901 }
25903 /* Deduce template arguments for the class template placeholder PTYPE for
25904 template TMPL based on the initializer INIT, and return the resulting
25905 type. */
25907 static tree
25909 tsubst_flags_t complain)
25910 {
25912 {
25913 /* We should have handled this in the caller. */
25919 }
25930 {
25933 {
25934 /* As an exception, the first phase in 16.3.1.7 (considering the
25935 initializer list as a single argument) is omitted if the
25936 initializer list consists of a single expression of type cv U,
25937 where U is a specialization of C or a class derived from a
25938 specialization of C. */
25949 }
25952 else
25954 }
25955 else
25966 /* Prune explicit deduction guides in copy-initialization context. */
25968 {
25974 {
25975 /* Found a nonconverting guide, prune the candidates. */
25982 }
25983 }
25988 {
25991 }
25994 // FIXME cache artificial deduction guides
25996 {
26001 else
26005 }
26009 /* If this is list-initialization and the class has a list constructor, first
26010 try deducing from the list as a single argument, as [over.match.list]. */
26014 {
26018 }
26020 {
26026 {
26027 /* That didn't work, now try treating the list as a sequence of
26028 arguments. */
26031 }
26032 }
26034 /* Maybe generate an implicit deduction guide. */
26036 {
26040 /* Generate a copy guide. */
26043 /* Generate a default guide. */
26047 {
26050 }
26051 }
26054 {
26056 " of %qT, as it has no non-explicit deduction guides or "
26059 }
26061 {
26065 }
26068 {
26072 }
26075 {
26085 }
26090 }
26092 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26093 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26094 The CONTEXT determines the context in which auto deduction is performed
26095 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26096 OUTER_TARGS are used during template argument deduction
26097 (context == adc_unify) to properly substitute the result, and is ignored
26098 in other contexts.
26100 For partial-concept-ids, extra args may be appended to the list of deduced
26101 template arguments prior to determining constraint satisfaction. */
26103 tree
26107 {
26108 tree targs;
26115 /* Defining a subset of type-dependent expressions that we can deduce
26116 from ahead of time isn't worth the trouble. */
26119 /* Similarly, we can't deduce from another undeduced decl. */
26124 /* C++17 class template argument deduction. */
26128 /* Nothing we can do with this, even in deduction context. */
26131 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26132 with either a new invented type template parameter U or, if the
26133 initializer is a braced-init-list (8.5.4), with
26134 std::initializer_list<U>. */
26136 {
26141 else
26142 {
26144 {
26148 "for deduction to %<std::initializer_list%>, use copy-"
26150 }
26152 }
26153 }
26164 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26165 and initializer has array type, deduce cv-qualified array type. */
26167 complain);
26169 {
26178 {
26182 }
26183 }
26184 else
26185 {
26187 tree tparms;
26191 else
26192 {
26196 }
26203 {
26205 /* Try again at instantiation time. */
26209 /* If type is error_mark_node a diagnostic must have been
26210 emitted by now. Also, having a mention to '<type error>'
26211 in the diagnostic is not really useful to the user. */
26212 {
26216 else
26221 }
26223 }
26224 }
26226 /* Check any placeholder constraints against the deduced type. */
26229 {
26230 /* Use the deduced type to check the associated constraints. If we
26231 have a partial-concept-id, rebuild the argument list so that
26232 we check using the extra arguments. */
26236 {
26239 }
26240 else
26243 {
26245 {
26247 {
26265 }
26267 }
26269 }
26270 }
26276 }
26278 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26279 result. */
26281 tree
26283 {
26285 {
26291 /* In an abbreviated function template we didn't know we were dealing
26292 with a function template when we saw the auto return type, so update
26293 it to have the correct level. */
26295 }
26297 }
26299 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26300 'decltype(auto)' or a deduced class template. */
26302 bool
26304 {
26310 else
26312 }
26314 /* for_each_template_parm callback for type_uses_auto. */
26316 int
26318 {
26320 }
26322 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26323 a use of `auto'. Returns NULL_TREE otherwise. */
26325 tree
26327 {
26331 {
26332 /* The Concepts TS allows multiple autos in one type-specifier; just
26333 return the first one we find, do_auto_deduction will collect all of
26334 them. */
26338 else
26340 }
26341 else
26343 }
26345 /* For a given template T, return the vector of typedefs referenced
26346 in T for which access check is needed at T instantiation time.
26347 T is either a FUNCTION_DECL or a RECORD_TYPE.
26348 Those typedefs were added to T by the function
26349 append_type_to_template_for_access_check. */
26353 {
26354 tree ti;
26365 {
26370 }
26373 }
26375 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26376 tied to T. That list of typedefs will be access checked at
26377 T instantiation time.
26378 T is either a FUNCTION_DECL or a RECORD_TYPE.
26379 TYPE_DECL is a TYPE_DECL node representing a typedef.
26380 SCOPE is the scope through which TYPE_DECL is accessed.
26381 LOCATION is the location of the usage point of TYPE_DECL.
26383 This function is a subroutine of
26384 append_type_to_template_for_access_check. */
26386 static void
26388 tree type_decl,
26389 tree scope,
26390 location_t location)
26391 {
26392 qualified_typedef_usage_t typedef_usage;
26393 tree ti;
26400 && type_decl
26414 }
26416 /* Append TYPE_DECL to the template TEMPL.
26417 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26418 At TEMPL instanciation time, TYPE_DECL will be checked to see
26419 if it can be accessed through SCOPE.
26420 LOCATION is the location of the usage point of TYPE_DECL.
26422 e.g. consider the following code snippet:
26424 class C
26425 {
26426 typedef int myint;
26427 };
26429 template<class U> struct S
26430 {
26431 C::myint mi; // <-- usage point of the typedef C::myint
26432 };
26434 S<char> s;
26436 At S<char> instantiation time, we need to check the access of C::myint
26437 In other words, we need to check the access of the myint typedef through
26438 the C scope. For that purpose, this function will add the myint typedef
26439 and the scope C through which its being accessed to a list of typedefs
26440 tied to the template S. That list will be walked at template instantiation
26441 time and access check performed on each typedefs it contains.
26442 Note that this particular code snippet should yield an error because
26443 myint is private to C. */
26445 void
26447 tree type_decl,
26448 tree scope,
26449 location_t location)
26450 {
26456 /* Make sure we don't append the type to the template twice. */
26463 }
26465 /* Convert the generic type parameters in PARM that match the types given in the
26466 range [START_IDX, END_IDX) from the current_template_parms into generic type
26467 packs. */
26469 tree
26471 {
26482 {
26483 /* Create a distinct parameter pack type from the current parm and add it
26484 to the replacement args to tsubst below into the generic function
26485 parameter. */
26500 }
26506 /* If there are more levels then build up the replacement with the outer
26507 template parms. */
26511 replacement);
26514 }
26516 /* Entries in the decl_constraint hash table. */
26518 {
26519 tree decl;
26520 tree ci;
26521 };
26523 /* Hashing function and equality for constraint entries. */
26525 {
26527 {
26529 }
26532 {
26534 }
26535 };
26537 /* A mapping from declarations to constraint information. Note that
26538 both templates and their underlying declarations are mapped to the
26539 same constraint information.
26541 FIXME: This is defined in pt.c because garbage collection
26542 code is not being generated for constraint.cc. */
26546 /* Returns the template constraints of declaration T. If T is not
26547 constrained, return NULL_TREE. Note that T must be non-null. */
26549 tree
26551 {
26562 else
26564 }
26566 /* Associate the given constraint information CI with the declaration
26567 T. If T is a template, then the constraints are associated with
26568 its underlying declaration. Don't build associations if CI is
26569 NULL_TREE. */
26571 void
26573 {
26585 }
26587 /* Remove the associated constraints of the declaration T. */
26589 void
26591 {
26600 }
26602 /* Memoized satisfaction results for declarations. This
26603 maps the pair (constraint_info, arguments) to the result computed
26604 by constraints_satisfied_p. */
26607 {
26608 tree ci;
26609 tree args;
26610 tree result;
26611 };
26613 /* Hashing function and equality for constraint entries. */
26616 {
26618 {
26621 }
26624 {
26626 }
26627 };
26629 /* Memoized satisfaction results for concept checks. */
26632 {
26633 tree tmpl;
26634 tree args;
26635 tree result;
26636 };
26638 /* Hashing function and equality for constraint entries. */
26641 {
26643 {
26645 }
26648 {
26653 }
26654 };
26659 /* Search for a memoized satisfaction result. Returns one of the
26660 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26662 tree
26664 {
26669 else
26671 }
26673 /* Memoize the result of a satisfication test. Returns the saved result. */
26675 tree
26677 {
26684 }
26686 /* Search for a memoized satisfaction result for a concept. */
26688 tree
26690 {
26695 else
26697 }
26699 /* Memoize the result of a concept check. Returns the saved result. */
26701 tree
26703 {
26710 }
26714 /* Returns a prior concept specialization. This returns the substituted
26715 and normalized constraints defined by the concept. */
26717 tree
26719 {
26724 else
26726 }
26728 /* Save a concept expansion for later. */
26730 tree
26732 {
26739 }
26741 static hashval_t
26743 {
26752 }
26754 /* Compare the constraints of two subsumption entries. The LEFT1 and
26755 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26756 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26758 static bool
26760 {
26768 }
26770 /* Key/value pair for learning and memoizing subsumption results. This
26771 associates a pair of check constraints (including arguments) with
26772 a boolean value indicating the result. */
26775 {
26776 tree t1;
26777 tree t2;
26779 };
26781 /* Hashing function and equality for constraint entries. */
26784 {
26786 {
26788 }
26791 {
26796 }
26797 };
26801 /* Search for a previously cached subsumption result. */
26805 {
26810 else
26812 }
26814 /* Save a subsumption result. */
26816 bool
26818 {
26825 }
26827 /* Set up the hash table for constraint association. */
26829 void
26831 {
26840 }
26842 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26843 0..N-1. */
26845 void
26847 {
26850 integer_type_node,
26851 NULL_TREE),
26855 }
26857 /* Set up the hash tables for template instantiations. */
26859 void
26861 {
26867 }
26869 /* Print stats about the template hash tables for -fstats. */
26871 void
26873 {
26882 }
26884 #if CHECKING_P
26888 /* Verify that build_non_dependent_expr () works, for various expressions,
26889 and that location wrappers don't affect the results. */
26891 static void
26893 {
26896 /* Verify constants, without and with location wrappers. */
26913 }
26915 /* Verify that type_dependent_expression_p () works correctly, even
26916 in the presence of location wrapper nodes. */
26918 static void
26920 {
26925 /* If no templates are involved, nothing is type-dependent. */
26931 /* Within a template, an unresolved name is always type-dependent. */
26934 /* Ensure it copes with NULL_TREE and errors. */
26938 /* A USING_DECL in a template should be type-dependent, even if wrapped
26939 with a location wrapper (PR c++/83799). */
26948 }
26950 /* Run all of the selftests within this file. */
26952 void
26954 {
26957 }