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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. Returns SPEC, or an
1477 equivalent prior declaration, if available.
1479 We also store instantiations of field packs in the hash table, even
1480 though they are not themselves templates, to make lookup easier. */
1482 static tree
1484 hashval_t hash)
1485 {
1486 tree fn;
1488 spec_entry elt;
1496 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1497 register it; we want the corresponding TEMPLATE_DECL instead.
1498 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1499 the more obvious `uses_template_parms (spec)' to avoid problems
1500 with default function arguments. In particular, given
1501 something like this:
1503 template <class T> void f(T t1, T t = T())
1505 the default argument expression is not substituted for in an
1506 instantiation unless and until it is actually needed. */
1510 /* We don't put these specializations in the hash table, but we might
1511 want to give an error about a mismatch. */
1513 else
1514 {
1522 slot =
1526 else
1528 }
1530 /* We can sometimes try to re-register a specialization that we've
1531 already got. In particular, regenerate_decl_from_template calls
1532 duplicate_decls which will update the specialization list. But,
1533 we'll still get called again here anyhow. It's more convenient
1534 to simply allow this than to try to prevent it. */
1538 {
1540 {
1543 {
1545 fn);
1547 }
1548 else
1549 {
1550 tree clone;
1551 /* This situation should occur only if the first
1552 specialization is an implicit instantiation, the
1553 second is an explicit specialization, and the
1554 implicit instantiation has not yet been used. That
1555 situation can occur if we have implicitly
1556 instantiated a member function and then specialized
1557 it later.
1559 We can also wind up here if a friend declaration that
1560 looked like an instantiation turns out to be a
1561 specialization:
1563 template <class T> void foo(T);
1564 class S { friend void foo<>(int) };
1565 template <> void foo(int);
1567 We transform the existing DECL in place so that any
1568 pointers to it become pointers to the updated
1569 declaration.
1571 If there was a definition for the template, but not
1572 for the specialization, we want this to look as if
1573 there were no definition, and vice versa. */
1576 /* The call to duplicate_decls will have applied
1577 [temp.expl.spec]:
1579 An explicit specialization of a function template
1580 is inline only if it is explicitly declared to be,
1581 and independently of whether its function template
1582 is.
1584 to the primary function; now copy the inline bits to
1585 the various clones. */
1587 {
1594 }
1598 }
1599 }
1601 {
1604 /* We've already complained in duplicate_decls. */
1608 /* Dup decl failed, but this is a new definition. Set the
1609 line number so any errors match this new
1610 definition. */
1614 }
1615 }
1619 /* A specialization must be declared in the same namespace as the
1620 template it is specializing. */
1626 {
1635 /* If TMPL is a forward declaration of a template function, keep a list
1636 of all specializations in case we need to reassign them to a friend
1637 template later in tsubst_friend_function.
1639 Also keep a list of all variable template instantiations so that
1640 process_partial_specialization can check whether a later partial
1641 specialization would have used it. */
1644 }
1647 }
1649 /* Returns true iff two spec_entry nodes are equivalent. */
1653 bool
1655 {
1662 /* tmpl could be a FIELD_DECL for a capture pack. */
1666 {
1667 /* Partial specializations of a variable template can be distinguished by
1668 constraints. */
1672 }
1676 }
1678 /* Returns a hash for a template TMPL and template arguments ARGS. */
1680 static hashval_t
1682 {
1685 }
1687 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1688 ignoring SPEC. */
1690 hashval_t
1692 {
1694 }
1696 /* Recursively calculate a hash value for a template argument ARG, for use
1697 in the hash tables of template specializations. */
1699 hashval_t
1701 {
1721 {
1729 {
1734 }
1756 {
1760 {
1763 }
1765 }
1769 {
1772 }
1783 val = iterative_hash_template_arg
1795 val);
1797 val);
1806 /* A lambda can't appear in a template arg, but don't crash on
1807 erroneous input. */
1819 /* Now hash operands as usual. */
1824 }
1827 {
1830 {
1831 // We want an alias specialization that survived strip_typedefs
1832 // to hash differently from its TYPE_CANONICAL, to avoid hash
1833 // collisions that compare as different in template_args_equal.
1834 // These could be dependent specializations that strip_typedefs
1835 // left alone, or untouched specializations because
1836 // coerce_template_parms returns the unconverted template
1837 // arguments if it sees incomplete argument packs.
1840 }
1843 val);
1846 /* Otherwise just compare the types during lookup. */
1855 {
1860 }
1861 }
1864 }
1866 /* Unregister the specialization SPEC as a specialization of TMPL.
1867 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1868 if the SPEC was listed as a specialization of TMPL.
1870 Note that SPEC has been ggc_freed, so we can't look inside it. */
1872 bool
1874 {
1876 spec_entry elt;
1884 {
1889 }
1892 }
1894 /* Like register_specialization, but for local declarations. We are
1895 registering SPEC, an instantiation of TMPL. */
1897 void
1899 {
1902 }
1904 /* TYPE is a class type. Returns true if TYPE is an explicitly
1905 specialized class. */
1907 bool
1909 {
1913 }
1915 /* Print the list of functions at FNS, going through all the overloads
1916 for each element of the list. Alternatively, FNS can not be a
1917 TREE_LIST, in which case it will be printed together with all the
1918 overloads.
1920 MORE and *STR should respectively be FALSE and NULL when the function
1921 is called from the outside. They are used internally on recursive
1922 calls. print_candidates manages the two parameters and leaves NULL
1923 in *STR when it ends. */
1925 static void
1927 {
1931 else
1933 {
1939 {
1942 else
1945 }
1947 }
1948 }
1950 /* Print the list of candidate FNS in an error message. FNS can also
1951 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1953 void
1955 {
1959 }
1961 /* Get a (possibly) constrained template declaration for the
1962 purpose of ordering candidates. */
1963 static tree
1965 {
1971 }
1973 /* Among candidates having the same signature, return the
1974 most constrained or NULL_TREE if there is no best candidate.
1975 If the signatures of candidates vary (e.g., template
1976 specialization vs. member function), then there can be no
1977 most constrained.
1979 Note that we don't compare constraints on the functions
1980 themselves, but rather those of their templates. */
1981 static tree
1983 {
1984 // Try to find the best candidate in a first pass.
1987 {
1994 }
1996 // Verify that the champ is better than previous candidates.
2001 }
2004 }
2007 /* Returns the template (one of the functions given by TEMPLATE_ID)
2008 which can be specialized to match the indicated DECL with the
2009 explicit template args given in TEMPLATE_ID. The DECL may be
2010 NULL_TREE if none is available. In that case, the functions in
2011 TEMPLATE_ID are non-members.
2013 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2014 specialization of a member template.
2016 The TEMPLATE_COUNT is the number of references to qualifying
2017 template classes that appeared in the name of the function. See
2018 check_explicit_specialization for a more accurate description.
2020 TSK indicates what kind of template declaration (if any) is being
2021 declared. TSK_TEMPLATE indicates that the declaration given by
2022 DECL, though a FUNCTION_DECL, has template parameters, and is
2023 therefore a template function.
2025 The template args (those explicitly specified and those deduced)
2026 are output in a newly created vector *TARGS_OUT.
2028 If it is impossible to determine the result, an error message is
2029 issued. The error_mark_node is returned to indicate failure. */
2031 static tree
2033 tree decl,
2037 tmpl_spec_kind tsk)
2038 {
2039 tree fns;
2040 tree targs;
2041 tree explicit_targs;
2044 /* A TREE_LIST of templates of which DECL may be a specialization.
2045 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2046 corresponding TREE_PURPOSE is the set of template arguments that,
2047 when used to instantiate the template, would produce a function
2048 with the signature of DECL. */
2058 /* We shouldn't be specializing a member template of an
2059 unspecialized class template; we already gave an error in
2060 check_specialization_scope, now avoid crashing. */
2063 {
2066 }
2074 /* Check for baselinks. */
2079 {
2082 }
2084 {
2087 }
2089 /* Count the number of template headers specified for this
2090 specialization. */
2100 {
2103 tf_warning_or_error,
2107 }
2109 {
2113 {
2114 tree decl_arg_types;
2115 tree fn_arg_types;
2116 tree insttype;
2118 /* In case of explicit specialization, we need to check if
2119 the number of template headers appearing in the specialization
2120 is correct. This is usually done in check_explicit_specialization,
2121 but the check done there cannot be exhaustive when specializing
2122 member functions. Consider the following code:
2124 template <> void A<int>::f(int);
2125 template <> template <> void A<int>::f(int);
2127 Assuming that A<int> is not itself an explicit specialization
2128 already, the first line specializes "f" which is a non-template
2129 member function, whilst the second line specializes "f" which
2130 is a template member function. So both lines are syntactically
2131 correct, and check_explicit_specialization does not reject
2132 them.
2134 Here, we can do better, as we are matching the specialization
2135 against the declarations. We count the number of template
2136 headers, and we check if they match TEMPLATE_COUNT + 1
2137 (TEMPLATE_COUNT is the number of qualifying template classes,
2138 plus there must be another header for the member template
2139 itself).
2141 Notice that if header_count is zero, this is not a
2142 specialization but rather a template instantiation, so there
2143 is no check we can perform here. */
2147 /* Check that the number of template arguments at the
2148 innermost level for DECL is the same as for FN. */
2156 /* DECL might be a specialization of FN. */
2160 /* For a non-static member function, we need to make sure
2161 that the const qualification is the same. Since
2162 get_bindings does not try to merge the "this" parameter,
2163 we must do the comparison explicitly. */
2169 /* Skip the "this" parameter and, for constructors of
2170 classes with virtual bases, the VTT parameter. A
2171 full specialization of a constructor will have a VTT
2172 parameter, but a template never will. */
2173 decl_arg_types
2175 fn_arg_types
2178 /* Function templates cannot be specializations; there are
2179 no partial specializations of functions. Therefore, if
2180 the type of DECL does not match FN, there is no
2181 match.
2183 Note that it should never be the case that we have both
2184 candidates added here, and for regular member functions
2185 below. */
2187 {
2191 }
2193 /* See whether this function might be a specialization of this
2194 template. Suppress access control because we might be trying
2195 to make this specialization a friend, and we have already done
2196 access control for the declaration of the specialization. */
2202 /* We cannot deduce template arguments that when used to
2203 specialize TMPL will produce DECL. */
2206 /* Remove, from the set of candidates, all those functions
2207 whose constraints are not satisfied. */
2211 // Then, try to form the new function type.
2215 fn_arg_types
2220 /* Save this template, and the arguments deduced. */
2222 }
2224 /* FN is an ordinary member function, and we need a
2225 specialization of a member template. */
2226 ;
2228 /* We can get IDENTIFIER_NODEs here in certain erroneous
2229 cases. */
2230 ;
2232 /* This is just an ordinary non-member function. Nothing can
2233 be a specialization of that. */
2234 ;
2236 /* Cannot specialize functions that are created implicitly. */
2237 ;
2238 else
2239 {
2240 tree decl_arg_types;
2242 /* This is an ordinary member function. However, since
2243 we're here, we can assume its enclosing class is a
2244 template class. For example,
2246 template <typename T> struct S { void f(); };
2247 template <> void S<int>::f() {}
2249 Here, S<int>::f is a non-template, but S<int> is a
2250 template class. If FN has the same type as DECL, we
2251 might be in business. */
2254 /* Its enclosing class is an explicit specialization
2255 of a template class. This is not a candidate. */
2260 /* The return types differ. */
2263 /* Adjust the type of DECL in case FN is a static member. */
2270 decl_arg_types))
2273 // If the deduced arguments do not satisfy the constraints,
2274 // this is not a candidate.
2278 // Add the candidate.
2280 }
2281 }
2284 {
2285 /* We have:
2287 [temp.expl.spec]
2289 It is possible for a specialization with a given function
2290 signature to be instantiated from more than one function
2291 template. In such cases, explicit specification of the
2292 template arguments must be used to uniquely identify the
2293 function template specialization being specialized.
2295 Note that here, there's no suggestion that we're supposed to
2296 determine which of the candidate templates is most
2297 specialized. However, we, also have:
2299 [temp.func.order]
2301 Partial ordering of overloaded function template
2302 declarations is used in the following contexts to select
2303 the function template to which a function template
2304 specialization refers:
2306 -- when an explicit specialization refers to a function
2307 template.
2309 So, we do use the partial ordering rules, at least for now.
2310 This extension can only serve to make invalid programs valid,
2311 so it's safe. And, there is strong anecdotal evidence that
2312 the committee intended the partial ordering rules to apply;
2313 the EDG front end has that behavior, and John Spicer claims
2314 that the committee simply forgot to delete the wording in
2315 [temp.expl.spec]. */
2318 {
2321 }
2322 }
2324 // Concepts allows multiple declarations of member functions
2325 // with the same signature. Like above, we need to rely on
2326 // on the partial ordering of those candidates to determine which
2327 // is the best.
2329 {
2331 {
2334 }
2335 }
2338 {
2345 else
2348 }
2352 {
2358 }
2360 /* We have one, and exactly one, match. */
2362 {
2366 // Propagate the candidate's constraints to the declaration.
2369 /* DECL is a re-declaration or partial instantiation of a template
2370 function. */
2373 /* It was a specialization of an ordinary member function in a
2374 template class. */
2376 }
2378 /* It was a specialization of a template. */
2381 {
2386 }
2387 else
2390 }
2392 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2393 but with the default argument values filled in from those in the
2394 TMPL_TYPES. */
2396 static tree
2398 tree tmpl_types)
2399 {
2400 tree new_spec_types;
2408 /* Substitute into the rest of the list. */
2409 new_spec_types =
2413 /* Add the default argument for this parameter. */
2416 new_spec_types);
2417 }
2419 /* DECL is an explicit specialization. Replicate default arguments
2420 from the template it specializes. (That way, code like:
2422 template <class T> void f(T = 3);
2423 template <> void f(double);
2424 void g () { f (); }
2426 works, as required.) An alternative approach would be to look up
2427 the correct default arguments at the call-site, but this approach
2428 is consistent with how implicit instantiations are handled. */
2430 static void
2432 {
2433 tree tmpl;
2434 tree spec_types;
2435 tree tmpl_types;
2436 tree new_spec_types;
2437 tree old_type;
2438 tree new_type;
2439 tree t;
2444 /* See if there's anything we need to do. */
2457 {
2458 /* Remove the this pointer, but remember the object's type for
2459 CV quals. */
2465 {
2466 /* DECL may contain more parameters than TMPL due to the extra
2467 in-charge parameter in constructors and destructors. */
2470 }
2472 {
2475 }
2476 }
2478 /* Compute the merged default arguments. */
2479 new_spec_types =
2482 /* Compute the new FUNCTION_TYPE. */
2484 {
2488 new_spec_types);
2491 /* Put the in-charge parameter back. */
2494 new_spec_types);
2498 new_spec_types);
2499 }
2500 else
2502 new_spec_types);
2512 }
2514 /* Return the number of template headers we expect to see for a definition
2515 or specialization of CTYPE or one of its non-template members. */
2517 int
2519 {
2523 {
2524 /* You're supposed to have one `template <...>' for every
2525 template class, but you don't need one for a full
2526 specialization. For example:
2528 template <class T> struct S{};
2529 template <> struct S<int> { void f(); };
2530 void S<int>::f () {}
2532 is correct; there shouldn't be a `template <>' for the
2533 definition of `S<int>::f'. */
2535 /* If CTYPE does not have template information of any
2536 kind, then it is not a template, nor is it nested
2537 within a template. */
2545 }
2548 }
2550 /* Do a simple sanity check on the template headers that precede the
2551 variable declaration DECL. */
2553 void
2555 {
2560 {
2563 "variable templates only available with "
2566 // Namespace-scope variable templates should have a template header.
2568 }
2570 {
2572 "too many template headers for %qD "
2578 "members of an explicitly specialized class are defined "
2580 }
2581 }
2583 /* An explicit specialization whose declarator-id or class-head-name is not
2584 qualified shall be declared in the nearest enclosing namespace of the
2585 template, or, if the namespace is inline (7.3.1), any namespace from its
2586 enclosing namespace set.
2588 If the name declared in the explicit instantiation is an unqualified name,
2589 the explicit instantiation shall appear in the namespace where its template
2590 is declared or, if that namespace is inline (7.3.1), any namespace from its
2591 enclosing namespace set. */
2593 void
2595 {
2600 {
2606 /* This was allowed in C++98, so only pedwarn. */
2608 "outside its namespace must use a nested-name-"
2610 }
2611 }
2613 /* Check to see if the function just declared, as indicated in
2614 DECLARATOR, and in DECL, is a specialization of a function
2615 template. We may also discover that the declaration is an explicit
2616 instantiation at this point.
2618 Returns DECL, or an equivalent declaration that should be used
2619 instead if all goes well. Issues an error message if something is
2620 amiss. Returns error_mark_node if the error is not easily
2621 recoverable.
2623 FLAGS is a bitmask consisting of the following flags:
2625 2: The function has a definition.
2626 4: The function is a friend.
2628 The TEMPLATE_COUNT is the number of references to qualifying
2629 template classes that appeared in the name of the function. For
2630 example, in
2632 template <class T> struct S { void f(); };
2633 void S<int>::f();
2635 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2636 classes are not counted in the TEMPLATE_COUNT, so that in
2638 template <class T> struct S {};
2639 template <> struct S<int> { void f(); }
2640 template <> void S<int>::f();
2642 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2643 invalid; there should be no template <>.)
2645 If the function is a specialization, it is marked as such via
2646 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2647 is set up correctly, and it is added to the list of specializations
2648 for that template. */
2650 tree
2652 tree decl,
2655 {
2664 tmpl_spec_kind tsk;
2667 {
2670 else
2672 }
2673 else
2677 {
2680 {
2683 }
2685 {
2687 /* This could be something like:
2689 template <class T> void f(T);
2690 class S { friend void f<>(int); } */
2692 else
2693 {
2694 /* This case handles bogus declarations like template <>
2695 template <class T> void f<int>(); */
2698 declarator);
2700 }
2701 }
2705 /* The error has already been reported in
2706 check_specialization_scope. */
2712 /* Fall through. */
2725 decl);
2728 else
2732 /* Fall through. */
2738 /* In cases like template<> constexpr bool v = true;
2739 We'll give an error in check_template_variable. */
2745 else
2751 {
2752 /* This case handles bogus declarations like template <>
2753 template <class T> void f<int>(); */
2757 declarator);
2759 {
2760 /* Partial specialization of variable template. */
2764 }
2768 else
2772 ok:;
2773 }
2776 /* This is a specialization of a member template, without
2777 specialization the containing class. Something like:
2779 template <class T> struct S {
2780 template <class U> void f (U);
2781 };
2782 template <> template <class U> void S<int>::f(U) {}
2784 That's a specialization -- but of the entire template. */
2790 }
2793 /* This doesn't apply to variable templates. */
2796 {
2800 {
2804 }
2805 }
2808 {
2813 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2815 {
2816 tree fns;
2821 else
2822 {
2823 /* If there is no class context, the explicit instantiation
2824 must be at namespace scope. */
2827 /* Find the namespace binding, using the declaration
2828 context. */
2832 /* If lookup fails, look for a friend declaration so we can
2833 give a better diagnostic. */
2839 {
2842 }
2843 }
2846 }
2852 {
2854 /* A specialization in class scope. This is invalid,
2855 but the error will already have been flagged by
2856 check_specialization_scope. */
2858 else
2859 {
2860 /* It's not valid to write an explicit instantiation in
2861 class scope, e.g.:
2863 class C { template void f(); }
2865 This case is caught by the parser. However, on
2866 something like:
2868 template class C { void f(); };
2870 (which is invalid) we can get here. The error will be
2871 issued later. */
2872 ;
2873 }
2876 }
2879 {
2880 // We'll match variable templates in start_decl.
2884 /* Find the list of functions in ctype that have the same
2885 name as the declared function. */
2889 {
2893 {
2894 /* From [temp.expl.spec]:
2896 If such an explicit specialization for the member
2897 of a class template names an implicitly-declared
2898 special member function (clause _special_), the
2899 program is ill-formed.
2901 Similar language is found in [temp.explicit]. */
2904 }
2907 }
2909 /* For a type-conversion operator, We might be looking for
2910 `operator int' which will be a specialization of
2911 `operator T'. Grab all the conversion operators, and
2912 then select from them. */
2917 {
2920 }
2921 else
2923 }
2925 /* Figure out what exactly is being specialized at this point.
2926 Note that for an explicit instantiation, even one for a
2927 member function, we cannot tell a priori whether the
2928 instantiation is for a member template, or just a member
2929 function of a template class. Even if a member template is
2930 being instantiated, the member template arguments may be
2931 elided if they can be deduced from the rest of the
2932 declaration. */
2935 member_specialization,
2936 template_count,
2937 tsk);
2940 /* We couldn't figure out what this declaration was
2941 specializing. */
2943 else
2944 {
2947 {
2949 "friend declaration %qD is not visible to "
2953 }
2961 {
2962 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2963 is done by do_decl_instantiation later. */
2969 {
2970 /* If TMPL is not the most general template (for
2971 example, if TMPL is a friend template that is
2972 injected into namespace scope), then there will
2973 be too many levels of TARGS. Remove some of them
2974 here. */
2976 tree new_targs;
2983 }
2986 }
2988 /* If we thought that the DECL was a member function, but it
2989 turns out to be specializing a static member function,
2990 make DECL a static member function as well. */
2996 /* If this is a specialization of a member template of a
2997 template class, we want to return the TEMPLATE_DECL, not
2998 the specialization of it. */
3000 {
3005 {
3006 tree parm;
3010 /* We want to use the argument list specified in the
3011 definition, not in the original declaration. */
3016 }
3019 }
3021 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3027 /* Inherit default function arguments from the template
3028 DECL is specializing. */
3032 /* This specialization has the same protection as the
3033 template it specializes. */
3037 /* 7.1.1-1 [dcl.stc]
3039 A storage-class-specifier shall not be specified in an
3040 explicit specialization...
3042 The parser rejects these, so unless action is taken here,
3043 explicit function specializations will always appear with
3044 global linkage.
3046 The action recommended by the C++ CWG in response to C++
3047 defect report 605 is to make the storage class and linkage
3048 of the explicit specialization match the templated function:
3050 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3051 */
3053 {
3057 /* A concept cannot be specialized. */
3059 {
3061 gen_tmpl);
3063 }
3065 /* This specialization has the same linkage and visibility as
3066 the function template it specializes. */
3069 {
3072 }
3075 {
3078 }
3079 }
3081 /* If DECL is a friend declaration, declared using an
3082 unqualified name, the namespace associated with DECL may
3083 have been set incorrectly. For example, in:
3085 template <typename T> void f(T);
3086 namespace N {
3087 struct S { friend void f<int>(int); }
3088 }
3090 we will have set the DECL_CONTEXT for the friend
3091 declaration to N, rather than to the global namespace. */
3096 /* This is not really a declaration of a specialization.
3097 It's just the name of an instantiation. But, it's not
3098 a request for an instantiation, either. */
3101 /* A specialization is not necessarily COMDAT. */
3107 /* If this is a full specialization, register it so that we can find
3108 it again. Partial specializations will be registered in
3109 process_partial_specialization. */
3114 /* A 'structor should already have clones. */
3120 }
3121 }
3124 }
3126 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3127 parameters. These are represented in the same format used for
3128 DECL_TEMPLATE_PARMS. */
3130 int
3132 {
3133 const_tree p1;
3134 const_tree p2;
3142 {
3154 {
3158 /* If either of the template parameters are invalid, assume
3159 they match for the sake of error recovery. */
3172 }
3173 }
3176 /* One set of parameters has more parameters lists than the
3177 other. */
3181 }
3183 /* Determine whether PARM is a parameter pack. */
3185 bool
3187 {
3188 /* Determine if we have a non-type template parameter pack. */
3195 /* If this is a list of template parameters, we could get a
3196 TYPE_DECL or a TEMPLATE_DECL. */
3200 /* Otherwise it must be a type template parameter. */
3204 }
3206 /* Determine if T is a function parameter pack. */
3208 bool
3210 {
3214 }
3216 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3217 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3219 tree
3221 {
3228 }
3230 /* Return true iff the function parameter PARAM_DECL was expanded
3231 from the function parameter pack PACK. */
3233 bool
3235 {
3240 /* The parameter pack and its pack arguments have the same
3241 DECL_PARM_INDEX. */
3243 }
3245 /* Determine whether ARGS describes a variadic template args list,
3246 i.e., one that is terminated by a template argument pack. */
3248 static bool
3250 {
3252 tree last_parm;
3266 }
3268 /* Generate a new name for the parameter pack name NAME (an
3269 IDENTIFIER_NODE) that incorporates its */
3271 static tree
3273 {
3274 /* Munge the name to include the parameter index. */
3275 #define NUMBUF_LEN 128
3289 }
3291 /* Return true if T is a primary function, class or alias template
3292 specialization, not including the template pattern. */
3294 bool
3296 {
3312 }
3314 /* Return true if PARM is a template template parameter. */
3316 bool
3318 {
3320 }
3322 /* Return true iff PARM is a DECL representing a type template
3323 parameter. */
3325 bool
3327 {
3332 }
3334 /* Return the template parameters of T if T is a
3335 primary template instantiation, NULL otherwise. */
3337 tree
3339 {
3344 parms = INNERMOST_TEMPLATE_PARMS
3348 }
3350 /* Return the template parameters of the LEVELth level from the full list
3351 of template parameters PARMS. */
3353 tree
3355 {
3356 tree p;
3367 }
3369 /* Returns the template arguments of T if T is a template instantiation,
3370 NULL otherwise. */
3372 tree
3374 {
3382 }
3384 /* Return the argument pack elements of T if T is a template argument pack,
3385 NULL otherwise. */
3387 tree
3389 {
3395 }
3397 /* True iff FN is a function representing a built-in variadic parameter
3398 pack. */
3400 bool
3402 {
3412 }
3414 /* True iff CALL is a call to a function representing a built-in variadic
3415 parameter pack. */
3417 static bool
3419 {
3423 }
3425 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3427 static tree
3429 tree in_decl)
3430 {
3436 {
3438 {
3441 }
3446 }
3447 else
3448 {
3452 /* Calculate the largest value of len that won't make the size of the vec
3453 overflow an int. The compiler will exceed resource limits long before
3454 this, but it seems a decent place to diagnose. */
3458 {
3463 }
3471 }
3472 }
3474 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3475 CALL. */
3477 static tree
3479 tree in_decl)
3480 {
3490 }
3492 /* Structure used to track the progress of find_parameter_packs_r. */
3493 struct find_parameter_pack_data
3494 {
3495 /* TREE_LIST that will contain all of the parameter packs found by
3496 the traversal. */
3499 /* Set of AST nodes that have been visited by the traversal. */
3502 /* True iff we're making a type pack expansion. */
3504 };
3506 /* Identifies all of the argument packs that occur in a template
3507 argument and appends them to the TREE_LIST inside DATA, which is a
3508 find_parameter_pack_data structure. This is a subroutine of
3509 make_pack_expansion and uses_parameter_packs. */
3510 static tree
3512 {
3518 /* Handle type aliases/typedefs. */
3520 {
3527 }
3529 /* Identify whether this is a parameter pack or not. */
3531 {
3539 /* FALLTHRU */
3541 /* If the placeholder appears in the decl-specifier-seq of a function
3542 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3543 is a pack expansion, the invented template parameter is a template
3544 parameter pack. */
3554 {
3555 /* We don't want to walk into the type of a PARM_DECL,
3556 because we don't want to see the type parameter pack. */
3559 }
3562 /* Look through a lambda capture proxy to the field pack. */
3565 {
3571 }
3573 {
3575 find_parameter_packs_r,
3578 }
3590 /* Not a parameter pack. */
3592 }
3595 {
3596 /* Add this parameter pack to the list. */
3598 }
3604 /* This switch statement will return immediately if we don't find a
3605 parameter pack. */
3607 {
3612 /* Check the template itself. */
3615 /* Check the template arguments. */
3629 /* Ignore the declaration of a capture proxy for a parameter pack. */
3637 /* Fall through. */
3682 {
3688 }
3691 {
3692 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3693 type_pack_expansion_p to false so that any placeholders
3694 within the expression don't get marked as parameter packs. */
3702 }
3706 }
3709 }
3711 /* Determines if the expression or type T uses any parameter packs. */
3712 bool
3714 {
3723 }
3725 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3726 representation a base-class initializer into a parameter pack
3727 expansion. If all goes well, the resulting node will be an
3728 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3729 respectively. */
3730 tree
3732 {
3733 tree result;
3742 {
3743 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3744 class initializer. In this case, the TREE_PURPOSE will be a
3745 _TYPE node (representing the base class expansion we're
3746 initializing) and the TREE_VALUE will be a TREE_LIST
3747 containing the initialization arguments.
3749 The resulting expansion looks somewhat different from most
3750 expansions. Rather than returning just one _EXPANSION, we
3751 return a TREE_LIST whose TREE_PURPOSE is a
3752 TYPE_PACK_EXPANSION containing the bases that will be
3753 initialized. The TREE_VALUE will be identical to the
3754 original TREE_VALUE, which is a list of arguments that will
3755 be passed to each base. We do not introduce any new pack
3756 expansion nodes into the TREE_VALUE (although it is possible
3757 that some already exist), because the TREE_PURPOSE and
3758 TREE_VALUE all need to be expanded together with the same
3759 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3760 resulting TREE_PURPOSE will mention the parameter packs in
3761 both the bases and the arguments to the bases. */
3762 tree purpose;
3763 tree value;
3766 /* Determine which parameter packs will be used by the base
3767 class expansion. */
3776 {
3779 arg);
3782 }
3785 {
3786 /* Collect the sets of parameter packs used in each of the
3787 initialization arguments. */
3789 {
3790 /* Determine which parameter packs will be expanded in this
3791 argument. */
3794 }
3795 }
3799 /* Create the pack expansion type for the base type. */
3805 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3806 they will rarely be compared to anything. */
3810 }
3815 /* Build the PACK_EXPANSION_* node. */
3816 result = for_types
3821 {
3822 /* Propagate type and const-expression information. */
3825 /* Mark this read now, since the expansion might be length 0. */
3827 }
3828 else
3829 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3830 they will rarely be compared to anything. */
3833 /* Determine which parameter packs will be expanded. */
3840 /* Make sure we found some parameter packs. */
3842 {
3844 {
3847 else
3849 }
3851 }
3857 }
3859 /* Checks T for any "bare" parameter packs, which have not yet been
3860 expanded, and issues an error if any are found. This operation can
3861 only be done on full expressions or types (e.g., an expression
3862 statement, "if" condition, etc.), because we could have expressions like:
3864 foo(f(g(h(args)))...)
3866 where "args" is a parameter pack. check_for_bare_parameter_packs
3867 should not be called for the subexpressions args, h(args),
3868 g(h(args)), or f(g(h(args))), because we would produce erroneous
3869 error messages.
3871 Returns TRUE and emits an error if there were bare parameter packs,
3872 returns FALSE otherwise. */
3873 bool
3875 {
3882 /* A lambda might use a parameter pack from the containing context. */
3896 {
3900 {
3911 else
3916 else
3920 }
3923 }
3926 }
3928 /* Expand any parameter packs that occur in the template arguments in
3929 ARGS. */
3930 tree
3932 {
3941 /* First, determine if we need to expand anything, and the number of
3942 slots we'll need. */
3944 {
3949 {
3953 else
3955 }
3956 else
3957 {
3959 num_result_args++;
3960 }
3961 }
3963 /* If no expansion is necessary, we're done. */
3967 /* Expand arguments. */
3970 non_default_args_count =
3973 {
3976 {
3983 }
3984 else
3985 {
3988 }
3989 }
3993 }
3995 /* Checks if DECL shadows a template parameter.
3997 [temp.local]: A template-parameter shall not be redeclared within its
3998 scope (including nested scopes).
4000 Emits an error and returns TRUE if the DECL shadows a parameter,
4001 returns FALSE otherwise. */
4003 bool
4005 {
4006 tree olddecl;
4008 /* If we're not in a template, we can't possibly shadow a template
4009 parameter. */
4013 /* Figure out what we're shadowing. */
4017 /* If there's no previous binding for this name, we're not shadowing
4018 anything, let alone a template parameter. */
4022 /* If we're not shadowing a template parameter, we're done. Note
4023 that OLDDECL might be an OVERLOAD (or perhaps even an
4024 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4025 node. */
4029 /* We check for decl != olddecl to avoid bogus errors for using a
4030 name inside a class. We check TPFI to avoid duplicate errors for
4031 inline member templates. */
4037 /* Don't complain about the injected class name, as we've already
4038 complained about the class itself. */
4045 else
4050 }
4052 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4053 ORIG_LEVEL, DECL, and TYPE. */
4055 static tree
4059 tree decl,
4060 tree type)
4061 {
4072 }
4074 /* Find the canonical type parameter for the given template type
4075 parameter. Returns the canonical type parameter, which may be TYPE
4076 if no such parameter existed. */
4078 static tree
4080 {
4081 tree list;
4095 else
4096 {
4100 }
4101 }
4103 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4104 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4105 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4106 new one is created. */
4108 static tree
4110 tsubst_flags_t complain)
4111 {
4116 {
4135 /* Template template parameters need this. */
4137 {
4144 }
4145 }
4148 }
4150 /* Process information from new template parameter PARM and append it
4151 to the LIST being built. This new parameter is a non-type
4152 parameter iff IS_NON_TYPE is true. This new parameter is a
4153 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4154 is in PARM_LOC. */
4156 tree
4159 {
4168 {
4172 {
4176 else
4178 }
4181 }
4184 {
4190 {
4191 /* [temp.param]
4193 The top-level cv-qualifiers on the template-parameter are
4194 ignored when determining its type. */
4199 && !is_parameter_pack
4200 /* If we're in a nested template parameter list, the template
4201 template parameter could be a parameter pack. */
4203 {
4204 /* This template parameter is not a parameter pack, but it
4205 should be. Complain about "bare" parameter packs. */
4208 /* Recover by calling this a parameter pack. */
4210 }
4211 }
4213 /* A template parameter is not modifiable. */
4222 processing_template_decl,
4227 }
4228 else
4229 {
4230 tree t;
4234 {
4236 /* This is for distinguishing between real templates and template
4237 template parameters */
4241 }
4242 else
4243 {
4245 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4248 }
4255 processing_template_decl,
4259 }
4263 /* Build requirements for the type/template parameter.
4264 This must be done after SET_DECL_TEMPLATE_PARM_P or
4265 process_template_parm could fail. */
4270 /* Build the parameter node linking the parameter declaration,
4271 its default argument (if any), and its constraints (if any). */
4276 }
4278 /* The end of a template parameter list has been reached. Process the
4279 tree list into a parameter vector, converting each parameter into a more
4280 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4281 as PARM_DECLs. */
4283 tree
4285 {
4290 /* Pop the dummy parameter level and add the real one. */
4293 current_template_parms
4298 {
4302 }
4307 }
4309 // Explicitly indicate the end of the template parameter list. We assume
4310 // that the current template parameters have been constructed and/or
4311 // managed explicitly, as when creating new template template parameters
4312 // from a shorthand constraint.
4313 void
4315 {
4317 }
4319 /* end_template_decl is called after a template declaration is seen. */
4321 void
4323 {
4329 /* This matches the pushlevel in begin_template_parm_list. */
4334 }
4336 /* Takes a TREE_LIST representing a template parameter and convert it
4337 into an argument suitable to be passed to the type substitution
4338 functions. Note that If the TREE_LIST contains an error_mark
4339 node, the returned argument is error_mark_node. */
4341 tree
4343 {
4356 {
4360 {
4361 /* Turn this argument into a TYPE_ARGUMENT_PACK
4362 with a single element, which expands T. */
4371 }
4372 }
4373 else
4374 {
4378 {
4379 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4380 with a single element, which expands T. */
4390 }
4391 else
4393 }
4395 }
4397 /* Given a single level of template parameters (a TREE_VEC), return it
4398 as a set of template arguments. */
4400 static tree
4402 {
4412 }
4414 /* Given a set of template parameters, return them as a set of template
4415 arguments. The template parameters are represented as a TREE_VEC, in
4416 the form documented in cp-tree.h for template arguments. */
4418 static tree
4420 {
4421 tree header;
4426 /* If there is only one level of template parameters, we do not
4427 create a TREE_VEC of TREE_VECs. Instead, we return a single
4428 TREE_VEC containing the arguments. */
4433 {
4438 else
4440 }
4443 }
4445 /* Within the declaration of a template, return the currently active
4446 template parameters as an argument TREE_VEC. */
4448 static tree
4450 {
4452 }
4454 /* Update the declared TYPE by doing any lookups which were thought to be
4455 dependent, but are not now that we know the SCOPE of the declarator. */
4457 tree
4459 {
4470 /* Don't bother building up the args in this case. */
4472 {
4473 /* tsubst in the args corresponding to the template parameters,
4474 including auto if present. Most things will be unchanged, but
4475 make_typename_type and tsubst_qualified_id will resolve
4476 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4479 tree pushed;
4481 {
4485 }
4490 }
4496 {
4499 else
4501 }
4503 }
4505 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4506 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4507 the new template is a member template. */
4509 tree
4511 {
4519 }
4521 struct template_parm_data
4522 {
4523 /* The level of the template parameters we are currently
4524 processing. */
4527 /* The index of the specialization argument we are currently
4528 processing. */
4531 /* An array whose size is the number of template parameters. The
4532 elements are nonzero if the parameter has been used in any one
4533 of the arguments processed so far. */
4536 /* An array whose size is the number of template arguments. The
4537 elements are nonzero if the argument makes use of template
4538 parameters of this level. */
4540 };
4542 /* Subroutine of push_template_decl used to see if each template
4543 parameter in a partial specialization is used in the explicit
4544 argument list. If T is of the LEVEL given in DATA (which is
4545 treated as a template_parm_data*), then DATA->PARMS is marked
4546 appropriately. */
4548 static int
4550 {
4558 {
4561 }
4563 /* In C++17 the type of a non-type argument is a deduced context. */
4568 data,
4569 NULL,
4572 /* Return zero so that for_each_template_parm will continue the
4573 traversal of the tree; we want to mark *every* template parm. */
4575 }
4577 /* Process the partial specialization DECL. */
4579 static tree
4581 {
4588 tree inner_parms;
4589 tree inst;
4599 /* A concept cannot be specialized. */
4601 {
4604 }
4609 /* We check that each of the template parameters given in the
4610 partial specialization is used in the argument list to the
4611 specialization. For example:
4613 template <class T> struct S;
4614 template <class T> struct S<T*>;
4616 The second declaration is OK because `T*' uses the template
4617 parameter T, whereas
4619 template <class T> struct S<int>;
4621 is no good. Even trickier is:
4623 template <class T>
4624 struct S1
4625 {
4626 template <class U>
4627 struct S2;
4628 template <class U>
4629 struct S2<T>;
4630 };
4632 The S2<T> declaration is actually invalid; it is a
4633 full-specialization. Of course,
4635 template <class U>
4636 struct S2<T (*)(U)>;
4638 or some such would have been OK. */
4646 {
4651 NULL,
4653 }
4656 {
4657 /* One of the template parms was not used in a deduced context in the
4658 specialization. */
4660 {
4664 }
4668 }
4673 /* [temp.class.spec]
4675 The argument list of the specialization shall not be identical to
4676 the implicit argument list of the primary template. */
4677 tree main_args
4680 && (!flag_concepts
4683 {
4687 else
4691 }
4693 /* A partial specialization that replaces multiple parameters of the
4694 primary template with a pack expansion is less specialized for those
4695 parameters. */
4697 {
4699 "primary template because it replaces multiple parameters "
4702 /* Avoid crash in process_partial_specialization. */
4704 }
4706 /* If we aren't in a dependent class, we can actually try deduction. */
4708 /* FIXME we should be able to handle a partial specialization of a
4709 partial instantiation, but currently we can't (c++/41727). */
4712 {
4716 maintmpl);
4717 }
4719 /* [temp.class.spec]
4721 A partially specialized non-type argument expression shall not
4722 involve template parameters of the partial specialization except
4723 when the argument expression is a simple identifier.
4725 The type of a template parameter corresponding to a specialized
4726 non-type argument shall not be dependent on a parameter of the
4727 specialization.
4729 Also, we verify that pack expansions only occur at the
4730 end of the argument list. */
4734 {
4741 {
4742 /* Extract the arguments from the argument pack. We'll be
4743 iterating over these in the following loop. */
4746 }
4749 {
4751 /* Get the Jth argument in the parameter pack. */
4755 {
4756 /* Pack expansions must come at the end of the
4757 argument list. */
4760 {
4764 else
4767 }
4768 }
4771 /* We only care about the pattern. */
4777 /* This next two lines are the `argument expression is not just a
4778 simple identifier' condition and also the `specialized
4779 non-type argument' bit. */
4783 {
4787 arg);
4788 else
4789 {
4790 /* Look at the corresponding template parameter,
4791 marking which template parameters its type depends
4792 upon. */
4796 {
4797 /* We haven't yet initialized TPD2. Do so now. */
4799 /* The number of parameters here is the number in the
4800 main template, which, as checked in the assertion
4801 above, is NARGS. */
4805 }
4807 /* Mark the template parameters. But this time, we're
4808 looking for the template parameters of the main
4809 template, not in the specialization. */
4816 NULL,
4820 {
4821 /* The type depended on some template parameters.
4822 If they are fully specialized in the
4823 specialization, that's OK. */
4832 "type %qT of template argument %qE depends "
4834 "type %qT of template argument %qE depends "
4836 type,
4837 arg);
4838 }
4839 }
4840 }
4841 }
4842 }
4844 /* We should only get here once. */
4848 // Build the template decl.
4857 /* Give template template parms a DECL_CONTEXT of the template
4858 for which they are a parameter. */
4860 {
4864 }
4867 /* We didn't register this in check_explicit_specialization so we could
4868 wait until the constraints were set. */
4870 else
4880 {
4886 {
4894 "declaration of %qD ambiguates earlier template "
4898 "partial specialization of %qD after instantiation "
4900 }
4901 }
4904 }
4906 /* PARM is a template parameter of some form; return the corresponding
4907 TEMPLATE_PARM_INDEX. */
4909 static tree
4911 {
4924 }
4926 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4927 parameter packs used by the template parameter PARM. */
4929 static void
4931 {
4932 /* A type parm can't refer to another parm. */
4936 {
4940 }
4947 }
4949 /* PARM is a template parameter pack. Return any parameter packs used in
4950 its type or the type of any of its template parameters. If there are
4951 any such packs, it will be instantiated into a fixed template parameter
4952 list by partial instantiation rather than be fully deduced. */
4954 tree
4956 {
4957 /* This can only be true in a member template. */
4960 /* This can only be true for a parameter pack. */
4963 /* A type parm can't refer to another parm. */
4977 }
4979 /* Check that a template declaration's use of default arguments and
4980 parameter packs is not invalid. Here, PARMS are the template
4981 parameters. IS_PRIMARY is true if DECL is the thing declared by
4982 a primary template. IS_PARTIAL is true if DECL is a partial
4983 specialization.
4985 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
4986 function template declaration or a friend class template
4987 declaration. In the function case, 1 indicates a declaration, 2
4988 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4989 emitted for extraneous default arguments.
4991 Returns TRUE if there were no errors found, FALSE otherwise. */
4993 bool
4996 {
4999 tree parm_level;
5002 /* [temp.param]
5004 A default template-argument shall not be specified in a
5005 function template declaration or a function template definition, nor
5006 in the template-parameter-list of the definition of a member of a
5007 class template. */
5011 /* You can't have a function template declaration in a local
5012 scope, nor you can you define a member of a class template in a
5013 local scope. */
5021 /* A lambda doesn't have an explicit declaration; don't complain
5022 about the parms of the enclosing class. */
5029 /* If this is either a friend defined in the scope of the class
5030 or a member function. */
5036 /* And, if it was a member function, it really was defined in
5037 the scope of the class. */
5040 /* We already checked these parameters when the template was
5041 declared, so there's no need to do it again now. This function
5042 was defined in class scope, but we're processing its body now
5043 that the class is complete. */
5046 /* Core issue 226 (C++0x only): the following only applies to class
5047 templates. */
5050 {
5051 /* [temp.param]
5053 If a template-parameter has a default template-argument, all
5054 subsequent template-parameters shall have a default
5055 template-argument supplied. */
5057 {
5064 {
5074 {
5076 /* For better subsequent error-recovery, we indicate that
5077 there should have been a default argument. */
5080 }
5082 && !is_friend_decl
5083 /* Don't complain about an enclosing partial
5084 specialization. */
5089 /* A fixed parameter pack will be partially
5090 instantiated into a fixed length list. */
5092 {
5093 /* A primary class template can only have one
5094 parameter pack, at the end of the template
5095 parameter list. */
5103 }
5104 }
5105 }
5106 }
5109 || is_partial
5110 || !is_primary
5112 /* For an ordinary class template, default template arguments are
5113 allowed at the innermost level, e.g.:
5114 template <class T = int>
5115 struct S {};
5116 but, in a partial specialization, they're not allowed even
5117 there, as we have in [temp.class.spec]:
5119 The template parameter list of a specialization shall not
5120 contain default template argument values.
5122 So, for a partial specialization, or for a function template
5123 (in C++98/C++03), we look at all of them. */
5124 ;
5125 else
5126 /* But, for a primary class template that is not a partial
5127 specialization we look at all template parameters except the
5128 innermost ones. */
5131 /* Figure out what error message to issue. */
5146 else
5147 /* Per [temp.param]/9, "A default template-argument shall not be
5148 specified in the template-parameter-lists of the definition of
5149 a member of a class template that appears outside of the member's
5150 class.", thus if we aren't handling a member of a class template
5151 there is no need to examine the parameters. */
5155 /* If we're inside a class definition, there's no need to
5156 examine the parameters to the class itself. On the one
5157 hand, they will be checked when the class is defined, and,
5158 on the other, default arguments are valid in things like:
5159 template <class T = double>
5160 struct S { template <class U> void f(U); };
5161 Here the default argument for `S' has no bearing on the
5162 declaration of `f'. */
5164 else
5165 /* Check everything. */
5171 {
5178 {
5183 {
5185 {
5192 }
5194 /* Clear out the default argument so that we are not
5195 confused later. */
5197 }
5198 }
5200 /* At this point, if we're still interested in issuing messages,
5201 they must apply to classes surrounding the object declared. */
5205 }
5208 }
5210 /* Worker for push_template_decl_real, called via
5211 for_each_template_parm. DATA is really an int, indicating the
5212 level of the parameters we are interested in. If T is a template
5213 parameter of that level, return nonzero. */
5215 static int
5217 {
5223 else
5226 }
5228 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5229 DATA is really an int, indicating the innermost outer level of parameters.
5230 If T is a template parameter of that level or further out, return
5231 nonzero. */
5233 static int
5235 {
5241 else
5244 }
5246 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5247 parameters given by current_template_args, or reuses a
5248 previously existing one, if appropriate. Returns the DECL, or an
5249 equivalent one, if it is replaced via a call to duplicate_decls.
5251 If IS_FRIEND is true, DECL is a friend declaration. */
5253 tree
5255 {
5256 tree tmpl;
5257 tree args;
5258 tree info;
5259 tree ctx;
5263 /* True if the template is a member template, in the sense of
5264 [temp.mem]. */
5270 /* See if this is a partial specialization. */
5283 /* For a friend, we want the context of the friend, not
5284 the type of which it is a friend. */
5288 /* In the case of a virtual function, we want the class in which
5289 it is defined. */
5291 else
5292 /* Otherwise, if we're currently defining some class, the DECL
5293 is assumed to be a member of the class. */
5302 /* See if this is a primary template. */
5305 /* A friend template that specifies a class context, i.e.
5306 template <typename T> friend void A<T>::f();
5307 is not primary. */
5312 else
5316 {
5323 {
5326 }
5328 {
5330 {
5333 }
5335 {
5336 /* [temp.mem]
5338 A destructor shall not be a member template. */
5341 }
5348 {
5349 /* [basic.stc.dynamic.allocation]
5351 An allocation function can be a function
5352 template. ... Template allocation functions shall
5353 have two or more parameters. */
5356 }
5357 }
5360 {
5361 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5364 {
5370 }
5371 }
5374 /* alias-declaration */
5378 else
5379 {
5382 }
5383 }
5385 /* Check to see that the rules regarding the use of default
5386 arguments are not being violated. We check args for a friend
5387 functions when we know whether it's a definition, introducing
5388 declaration or re-declaration. */
5393 /* Ensure that there are no parameter packs in the type of this
5394 declaration that have not been expanded. */
5396 {
5397 /* Check each of the arguments individually to see if there are
5398 any bare parameter packs. */
5404 {
5407 {
5408 /* This is a PARM_DECL that contains unexpanded parameter
5409 packs. We have already complained about this in the
5410 check_for_bare_parameter_packs call, so just replace
5411 these types with ERROR_MARK_NODE. */
5414 }
5418 }
5420 /* Check for bare parameter packs in the return type and the
5421 exception specifiers. */
5423 /* Errors were already issued, set return type to int
5424 as the frontend doesn't expect error_mark_node as
5425 the return type. */
5429 }
5434 {
5437 }
5450 {
5455 /* If DECL is a TYPE_DECL for a class-template, then there won't
5456 be DECL_LANG_SPECIFIC. The information equivalent to
5457 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5461 {
5462 /* Since a template declaration already existed for this
5463 class-type, we must be redeclaring it here. Make sure
5464 that the redeclaration is valid. */
5466 current_template_parms,
5468 /* We don't need to create a new TEMPLATE_DECL; just use the
5469 one we already had. */
5471 }
5472 else
5473 {
5475 member_template_p);
5480 {
5481 /* A specialization of a member template of a template
5482 class. */
5486 }
5487 }
5488 }
5489 else
5490 {
5496 {
5499 }
5507 {
5508 tree new_tmpl;
5510 /* The declaration is a specialization of a member
5511 template, declared outside the class. Therefore, the
5512 innermost template arguments will be NULL, so we
5513 replace them with the arguments determined by the
5514 earlier call to check_explicit_specialization. */
5517 new_tmpl
5519 member_template_p);
5529 args,
5532 }
5534 /* Make sure the template headers we got make sense. */
5539 {
5544 }
5545 else
5547 {
5552 {
5556 else
5560 /* Avoid crash in import_export_decl. */
5563 }
5568 /* Can happen in erroneous input. */
5570 else
5572 }
5574 /* Check that the parms are used in the appropriate qualifying scopes
5575 in the declarator. */
5579 {
5585 /* Avoid crash in import_export_decl. */
5588 }
5589 }
5594 /* Push template declarations for global functions and types. Note
5595 that we do not try to push a global template friend declared in a
5596 template class; such a thing may well depend on the template
5597 parameters of the class. */
5600 {
5605 /* Hide template friend classes that haven't been declared yet. */
5607 {
5610 }
5611 }
5614 {
5619 /* Give template template parms a DECL_CONTEXT of the template
5620 for which they are a parameter. */
5623 {
5627 }
5633 }
5635 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5636 back to its most general template. If TMPL is a specialization,
5637 ARGS may only have the innermost set of arguments. Add the missing
5638 argument levels if necessary. */
5646 else
5647 {
5652 }
5655 && !is_friend
5658 /* Set DECL_COMDAT on template instantiations; if we force
5659 them to be emitted by explicit instantiation or -frepo,
5660 mark_needed will tell cgraph to do the right thing. */
5664 }
5666 tree
5668 {
5670 }
5672 /* FN is an inheriting constructor that inherits from the constructor
5673 template INHERITED; turn FN into a constructor template with a matching
5674 template header. */
5676 tree
5678 {
5679 tree inner_parms
5682 tree parms
5693 }
5695 /* Called when a class template TYPE is redeclared with the indicated
5696 template PARMS, e.g.:
5698 template <class T> struct S;
5699 template <class T> struct S {}; */
5701 bool
5703 {
5704 tree tmpl;
5705 tree tmpl_parms;
5709 {
5712 }
5716 /* The type is nested in some template class. Nothing to worry
5717 about here; there are no new template parameters for the nested
5718 type. */
5722 {
5724 tmpl);
5726 }
5732 {
5742 }
5745 {
5746 tree tmpl_parm;
5747 tree parm;
5748 tree tmpl_default;
5749 tree parm_default;
5763 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5764 TEMPLATE_DECL. */
5774 {
5778 }
5781 {
5782 /* We have in [temp.param]:
5784 A template-parameter may not be given default arguments
5785 by two different declarations in the same scope. */
5790 }
5793 /* Update the previous template parameters (which are the ones
5794 that will really count) with the new default value. */
5797 /* Update the new parameters, too; they'll be used as the
5798 parameters for any members. */
5801 /* Give each template template parm in this redeclaration a
5802 DECL_CONTEXT of the template for which they are a parameter. */
5804 {
5807 }
5811 }
5813 // Cannot redeclare a class template with a different set of constraints.
5815 {
5820 }
5823 }
5825 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5826 to be used when the caller has already checked
5827 (processing_template_decl
5828 && !instantiation_dependent_expression_p (expr)
5829 && potential_constant_expression (expr))
5830 and cleared processing_template_decl. */
5832 tree
5834 {
5837 complain,
5841 }
5843 /* Simplify EXPR if it is a non-dependent expression. Returns the
5844 (possibly simplified) expression. */
5846 tree
5848 {
5852 /* If we're in a template, but EXPR isn't value dependent, simplify
5853 it. We're supposed to treat:
5855 template <typename T> void f(T[1 + 1]);
5856 template <typename T> void f(T[2]);
5858 as two declarations of the same function, for example. */
5861 {
5862 processing_template_decl_sentinel s;
5864 }
5866 }
5868 tree
5870 {
5872 }
5874 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5875 an uninstantiated expression. */
5877 tree
5879 {
5883 {
5886 else
5887 {
5888 processing_template_decl_sentinel s;
5890 }
5891 }
5893 }
5895 /* True iff T is a specialization of a variable template. */
5897 bool
5899 {
5904 }
5906 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5907 template declaration, or a TYPE_DECL for an alias declaration. */
5909 bool
5911 {
5919 }
5921 /* Return TRUE iff T is a specialization of an alias template. */
5923 bool
5925 {
5926 /* It's an alias template specialization if it's an alias and its
5927 TYPE_NAME is a specialization of a primary template. */
5933 }
5935 /* An alias template is complex from a SFINAE perspective if a template-id
5936 using that alias can be ill-formed when the expansion is not, as with
5937 the void_t template. We determine this by checking whether the
5938 expansion for the alias template uses all its template parameters. */
5940 struct uses_all_template_parms_data
5941 {
5944 };
5946 static int
5948 {
5956 }
5958 static bool
5960 {
5975 }
5977 /* Return TRUE iff T is a specialization of a complex alias template with
5978 dependent template-arguments. */
5980 bool
5982 {
5995 }
5997 /* Return the number of innermost template parameters in TMPL. */
5999 static int
6001 {
6004 }
6006 /* Return either TMPL or another template that it is equivalent to under DR
6007 1286: An alias that just changes the name of a template is equivalent to
6008 the other template. */
6010 static tree
6012 {
6015 {
6016 /* Determine if the alias is equivalent to an underlying template. */
6028 tree alias_args = INNERMOST_TEMPLATE_ARGS
6033 /* Alias is equivalent. Strip it and repeat. */
6035 }
6038 }
6040 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6041 must be a reference-to-function or a pointer-to-function type, as specified
6042 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6043 and check that the resulting function has external linkage. */
6045 static tree
6047 tsubst_flags_t complain)
6048 {
6051 linkage_kind linkage;
6066 /* [temp.arg.nontype]/1
6068 A template-argument for a non-type, non-template template-parameter
6069 shall be one of:
6070 [...]
6071 -- the address of an object or function with external [C++11: or
6072 internal] linkage. */
6075 {
6077 {
6083 else
6086 }
6088 }
6092 {
6094 {
6099 else
6103 }
6105 }
6107 accept:
6114 }
6116 /* Subroutine of convert_nontype_argument.
6117 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6118 Emit an error otherwise. */
6120 static bool
6122 tsubst_flags_t complain)
6123 {
6140 {
6145 else
6147 }
6149 }
6151 /* Returns TRUE iff the address of OP is value-dependent.
6153 14.6.2.4 [temp.dep.temp]:
6154 A non-integral non-type template-argument is dependent if its type is
6155 dependent or it has either of the following forms
6156 qualified-id
6157 & qualified-id
6158 and contains a nested-name-specifier which specifies a class-name that
6159 names a dependent type.
6161 We generalize this to just say that the address of a member of a
6162 dependent class is value-dependent; the above doesn't cover the
6163 address of a static data member named with an unqualified-id. */
6165 static bool
6167 {
6168 /* We could use get_inner_reference here, but there's no need;
6169 this is only relevant for template non-type arguments, which
6170 can only be expressed as &id-expression. */
6172 {
6176 }
6179 }
6181 /* The next set of functions are used for providing helpful explanatory
6182 diagnostics for failed overload resolution. Their messages should be
6183 indented by two spaces for consistency with the messages in
6184 call.c */
6186 static int
6188 {
6190 }
6192 /* Other failure functions should call this one, to provide a single function
6193 for setting a breakpoint on. */
6195 static int
6197 {
6199 }
6201 static int
6203 {
6208 }
6210 static int
6212 {
6218 }
6220 static int
6222 {
6226 }
6228 static int
6230 {
6233 " template parameter %qD is not a parameter pack, but "
6237 }
6239 static int
6241 {
6244 " template argument %qE does not match "
6248 }
6250 static int
6252 {
6256 }
6258 static int
6260 {
6266 }
6268 static int
6270 {
6272 {
6277 else
6279 " deduced conflicting values for non-type parameter "
6281 }
6283 }
6285 static int
6287 {
6290 " variable-sized array type %qT is not "
6292 arg);
6294 }
6296 static int
6298 {
6302 arg);
6304 }
6306 static int
6308 {
6310 {
6316 else
6321 }
6323 }
6325 static int
6327 {
6329 }
6331 static int
6334 {
6336 }
6338 static int
6341 {
6347 }
6349 static int
6352 {
6355 {
6363 }
6365 }
6367 static int
6369 {
6372 " template parameters of a template template argument are "
6375 }
6377 static int
6379 {
6385 }
6387 static int
6389 {
6394 }
6396 /* Attempt to convert the non-type template parameter EXPR to the
6397 indicated TYPE. If the conversion is successful, return the
6398 converted value. If the conversion is unsuccessful, return
6399 NULL_TREE if we issued an error message, or error_mark_node if we
6400 did not. We issue error messages for out-and-out bad template
6401 parameters, but not simply because the conversion failed, since we
6402 might be just trying to do argument deduction. Both TYPE and EXPR
6403 must be non-dependent.
6405 The conversion follows the special rules described in
6406 [temp.arg.nontype], and it is much more strict than an implicit
6407 conversion.
6409 This function is called twice for each template argument (see
6410 lookup_template_class for a more accurate description of this
6411 problem). This means that we need to handle expressions which
6412 are not valid in a C++ source, but can be created from the
6413 first call (for instance, casts to perform conversions). These
6414 hacks can go away after we fix the double coercion problem. */
6416 static tree
6418 {
6419 tree expr_type;
6423 /* Detect immediately string literals as invalid non-type argument.
6424 This special-case is not needed for correctness (we would easily
6425 catch this later), but only to provide better diagnostic for this
6426 common user mistake. As suggested by DR 100, we do not mention
6427 linkage issues in the diagnostic as this is not the point. */
6428 /* FIXME we're making this OK. */
6430 {
6436 }
6438 /* Add the ADDR_EXPR now for the benefit of
6439 value_dependent_expression_p. */
6442 {
6446 }
6448 /* If we are in a template, EXPR may be non-dependent, but still
6449 have a syntactic, rather than semantic, form. For example, EXPR
6450 might be a SCOPE_REF, rather than the VAR_DECL to which the
6451 SCOPE_REF refers. Preserving the qualifying scope is necessary
6452 so that access checking can be performed when the template is
6453 instantiated -- but here we need the resolved form so that we can
6454 convert the argument. */
6466 /* If the argument is non-dependent, perform any conversions in
6467 non-dependent context as well. */
6475 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6476 to a non-type argument of "nullptr". */
6480 /* In C++11, integral or enumeration non-type template arguments can be
6481 arbitrary constant expressions. Pointer and pointer to
6482 member arguments can be general constant expressions that evaluate
6483 to a null value, but otherwise still need to be of a specific form. */
6485 {
6487 /* A PTRMEM_CST is already constant, and a valid template
6488 argument for a parameter of pointer to member type, we just want
6489 to leave it in that form rather than lower it to a
6493 {
6494 /* C++17: A template-argument for a non-type template-parameter shall
6495 be a converted constant expression (8.20) of the type of the
6496 template-parameter. */
6502 }
6504 {
6509 }
6510 }
6514 else
6517 /* HACK: Due to double coercion, we can get a
6518 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6519 which is the tree that we built on the first call (see
6520 below when coercing to reference to object or to reference to
6521 function). We just strip everything and get to the arg.
6522 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6523 for examples. */
6525 {
6531 {
6532 /* ??? Maybe we could use convert_from_reference here, but we
6533 would need to relax its constraints because the NOP_EXPR
6534 could actually change the type to something more cv-qualified,
6535 and this is not folded by convert_from_reference. */
6540 && (same_type_ignoring_top_level_qualifiers_p
6543 {
6546 }
6547 }
6548 }
6550 /* [temp.arg.nontype]/5, bullet 1
6552 For a non-type template-parameter of integral or enumeration type,
6553 integral promotions (_conv.prom_) and integral conversions
6554 (_conv.integral_) are applied. */
6556 {
6558 {
6563 }
6568 /* Notice that there are constant expressions like '4 % 0' which
6569 do not fold into integer constants. */
6572 {
6574 {
6578 else
6584 /* else cxx_constant_value complained but gave us
6585 a real constant, so go ahead. */
6587 {
6588 /* Some assemble time constant expressions like
6589 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6590 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6591 as we can emit them into .rodata initializers of
6592 variables, yet they can't fold into an INTEGER_CST at
6593 compile time. Refuse them here. */
6598 }
6599 }
6600 else
6602 }
6604 /* Avoid typedef problems. */
6607 }
6608 /* [temp.arg.nontype]/5, bullet 2
6610 For a non-type template-parameter of type pointer to object,
6611 qualification conversions (_conv.qual_) and the array-to-pointer
6612 conversion (_conv.array_) are applied. */
6614 {
6617 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6618 decay_conversion or an explicit cast. If it's a problematic cast,
6619 we'll complain about it below. */
6621 {
6626 {
6629 }
6630 }
6632 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6634 A template-argument for a non-type, non-template template-parameter
6635 shall be one of: [...]
6637 -- the name of a non-type template-parameter;
6638 -- the address of an object or function with external linkage, [...]
6639 expressed as "& id-expression" where the & is optional if the name
6640 refers to a function or array, or if the corresponding
6641 template-parameter is a reference.
6643 Here, we do not care about functions, as they are invalid anyway
6644 for a parameter of type pointer-to-object. */
6647 /* Non-type template parameters are OK. */
6648 ;
6652 {
6654 {
6657 "because %qD is a variable, not the address of "
6660 }
6662 {
6668 }
6669 /* Other values, like integer constants, might be valid
6670 non-type arguments of some other type. */
6672 }
6673 else
6674 {
6678 {
6683 }
6685 {
6691 }
6694 {
6699 }
6700 /* C++17: For a non-type template-parameter of reference or pointer
6701 type, the value of the constant expression shall not refer to (or
6702 for a pointer type, shall not be the address of):
6703 * a subobject (4.5),
6704 * a temporary object (15.2),
6705 * a string literal (5.13.5),
6706 * the result of a typeid expression (8.2.8), or
6707 * a predefined __func__ variable (11.4.1). */
6709 {
6712 decl);
6714 }
6718 {
6723 }
6725 {
6729 decl);
6731 }
6732 }
6739 }
6740 /* [temp.arg.nontype]/5, bullet 3
6742 For a non-type template-parameter of type reference to object, no
6743 conversions apply. The type referred to by the reference may be more
6744 cv-qualified than the (otherwise identical) type of the
6745 template-argument. The template-parameter is bound directly to the
6746 template-argument, which must be an lvalue. */
6748 {
6750 expr_type))
6754 {
6759 }
6762 {
6767 }
6769 /* [temp.arg.nontype]/1
6771 A template-argument for a non-type, non-template template-parameter
6772 shall be one of: [...]
6774 -- the address of an object or function with external linkage. */
6777 {
6780 {
6783 "because a reference variable does not have a constant "
6786 }
6787 }
6791 /* OK, dependent reference. We don't want to ask whether a DECL is
6793 else
6794 {
6796 {
6802 }
6804 /* DR 1155 allows internal linkage in C++11 and up. */
6807 {
6813 }
6816 }
6820 }
6821 /* [temp.arg.nontype]/5, bullet 4
6823 For a non-type template-parameter of type pointer to function, only
6824 the function-to-pointer conversion (_conv.func_) is applied. If the
6825 template-argument represents a set of overloaded functions (or a
6826 pointer to such), the matching function is selected from the set
6827 (_over.over_). */
6829 {
6830 /* If the argument is a template-id, we might not have enough
6831 context information to decay the pointer. */
6833 {
6837 }
6840 /* Null pointer values are OK in C++11. */
6846 }
6847 /* [temp.arg.nontype]/5, bullet 5
6849 For a non-type template-parameter of type reference to function, no
6850 conversions apply. If the template-argument represents a set of
6851 overloaded functions, the matching function is selected from the set
6852 (_over.over_). */
6854 {
6856 {
6858 {
6863 }
6865 }
6870 }
6871 /* [temp.arg.nontype]/5, bullet 6
6873 For a non-type template-parameter of type pointer to member function,
6874 no conversions apply. If the template-argument represents a set of
6875 overloaded member functions, the matching member function is selected
6876 from the set (_over.over_). */
6878 {
6883 /* [temp.arg.nontype] bullet 1 says the pointer to member
6884 expression must be a pointer-to-member constant. */
6889 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6890 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6893 }
6894 /* [temp.arg.nontype]/5, bullet 7
6896 For a non-type template-parameter of type pointer to data member,
6897 qualification conversions (_conv.qual_) are applied. */
6899 {
6900 /* [temp.arg.nontype] bullet 1 says the pointer to member
6901 expression must be a pointer-to-member constant. */
6909 }
6911 {
6913 {
6918 }
6920 }
6921 /* A template non-type parameter must be one of the above. */
6922 else
6925 /* Sanity check: did we actually convert the argument to the
6926 right type? */
6930 }
6932 /* Subroutine of coerce_template_template_parms, which returns 1 if
6933 PARM_PARM and ARG_PARM match using the rule for the template
6934 parameters of template template parameters. Both PARM and ARG are
6935 template parameters; the rest of the arguments are the same as for
6936 coerce_template_template_parms.
6937 */
6938 static int
6940 tree arg,
6941 tsubst_flags_t complain,
6942 tree in_decl,
6943 tree outer_args)
6944 {
6953 {
6955 /* We encounter instantiations of templates like
6956 template <template <template <class> class> class TT>
6957 class C; */
6958 {
6965 }
6966 /* Fall through. */
6971 /* Argument is a parameter pack but parameter is not. */
6976 /* The tsubst call is used to handle cases such as
6978 template <int> class C {};
6979 template <class T, template <T> class TT> class D {};
6980 D<int, C> d;
6982 i.e. the parameter list of TT depends on earlier parameters. */
6984 {
6989 }
6993 /* Argument is a parameter pack but parameter is not. */
7000 }
7003 }
7005 /* Coerce template argument list ARGLIST for use with template
7006 template-parameter TEMPL. */
7008 static tree
7010 tsubst_flags_t complain)
7011 {
7012 /* Consider an example where a template template parameter declared as
7014 template <class T, class U = std::allocator<T> > class TT
7016 The template parameter level of T and U are one level larger than
7017 of TT. To proper process the default argument of U, say when an
7018 instantiation `TT<int>' is seen, we need to build the full
7019 arguments containing {int} as the innermost level. Outer levels,
7020 available when not appearing as default template argument, can be
7021 obtained from the arguments of the enclosing template.
7023 Suppose that TT is later substituted with std::vector. The above
7024 instantiation is `TT<int, std::allocator<T> >' with TT at
7025 level 1, and T at level 2, while the template arguments at level 1
7026 becomes {std::vector} and the inner level 2 is {int}. */
7030 {
7032 /* We want arguments for the partial specialization, not arguments for
7033 the primary template. */
7035 else
7037 }
7039 {
7040 /* This is an argument of the current template, so we haven't set
7041 DECL_CONTEXT yet. */
7042 tree relevant_template_parms;
7044 /* Parameter levels that are greater than the level of the given
7045 template template parm are irrelevant. */
7052 }
7059 complain,
7062 }
7064 /* A cache of template template parameters with match-all default
7065 arguments. */
7067 static void
7069 {
7073 }
7074 static tree
7076 {
7081 }
7083 /* T is a bound template template-parameter. Copy its arguments into default
7084 arguments of the template template-parameter's template parameters. */
7086 static tree
7088 {
7111 {
7114 {
7117 }
7118 }
7122 }
7124 /* ARG is a bound potential template template-argument, and PARGS is a list
7125 of arguments for the corresponding template template-parameter. Adjust
7126 PARGS as appropriate for application to ARG's template, and if ARG is a
7127 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7128 arguments to the template template parameter. */
7130 static tree
7132 {
7136 {
7137 /* When comparing two template template-parameters in partial ordering,
7138 rewrite the one currently being used as an argument to have default
7139 arguments for all parameters. */
7145 }
7146 else
7147 {
7148 tree aparms
7153 }
7156 }
7158 /* Subroutine of unify for the case when PARM is a
7159 BOUND_TEMPLATE_TEMPLATE_PARM. */
7161 static int
7164 {
7168 /* The template template parm might be variadic and the argument
7169 not, so flatten both argument lists. */
7174 {
7175 /* In keeping with P0522R0, adjust P's template arguments
7176 to apply to A's template; then flatten it again. */
7185 /* If the P0522 adjustment eliminated a pack expansion, deduce
7186 empty packs. */
7192 }
7193 else
7194 {
7195 /* Deduce arguments T, i from TT<T> or TT<i>.
7196 We check each element of PARMVEC and ARGVEC individually
7197 rather than the whole TREE_VEC since they can have
7198 different number of elements, which is allowed under N2555. */
7202 /* Check if the parameters end in a pack, making them
7203 variadic. */
7210 /* If the template argument list of P contains a pack
7211 expansion that is not the last template argument, the
7212 entire template argument list is a non-deduced
7213 context. */
7231 DEDUCE_EXACT,
7234 }
7237 }
7239 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7240 template template parameters. Both PARM_PARMS and ARG_PARMS are
7241 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7242 or PARM_DECL.
7244 Consider the example:
7245 template <class T> class A;
7246 template<template <class U> class TT> class B;
7248 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7249 the parameters to A, and OUTER_ARGS contains A. */
7251 static int
7253 tree arg_parms,
7254 tsubst_flags_t complain,
7255 tree in_decl,
7256 tree outer_args)
7257 {
7269 {
7270 /* P0522R0: A template template-parameter P is at least as specialized as
7271 a template template-argument A if, given the following rewrite to two
7272 function templates, the function template corresponding to P is at
7273 least as specialized as the function template corresponding to A
7274 according to the partial ordering rules for function templates
7275 ([temp.func.order]). Given an invented class template X with the
7276 template parameter list of A (including default arguments):
7278 * Each of the two function templates has the same template parameters,
7279 respectively, as P or A.
7281 * Each function template has a single function parameter whose type is
7282 a specialization of X with template arguments corresponding to the
7283 template parameters from the respective function template where, for
7284 each template parameter PP in the template parameter list of the
7285 function template, a corresponding template argument AA is formed. If
7286 PP declares a parameter pack, then AA is the pack expansion
7287 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7289 If the rewrite produces an invalid type, then P is not at least as
7290 specialized as A. */
7292 /* So coerce P's args to apply to A's parms, and then deduce between A's
7293 args and the converted args. If that succeeds, A is at least as
7294 specialized as P, so they match.*/
7301 {
7307 }
7308 }
7310 /* Determine whether we have a parameter pack at the end of the
7311 template template parameter's template parameter list. */
7313 {
7320 {
7334 }
7335 }
7341 /* Check all of the template parameters except the parameter pack at
7342 the end (if any). */
7344 {
7353 outer_args))
7356 }
7359 {
7360 /* Check each of the template parameters in the template
7361 argument against the template parameter pack at the end of
7362 the template template parameter. */
7369 {
7376 outer_args))
7378 }
7379 }
7382 }
7384 /* Verifies that the deduced template arguments (in TARGS) for the
7385 template template parameters (in TPARMS) represent valid bindings,
7386 by comparing the template parameter list of each template argument
7387 to the template parameter list of its corresponding template
7388 template parameter, in accordance with DR150. This
7389 routine can only be called after all template arguments have been
7390 deduced. It will return TRUE if all of the template template
7391 parameter bindings are okay, FALSE otherwise. */
7392 bool
7394 {
7398 /* We're dealing with template parms in this process. */
7404 {
7409 {
7414 {
7415 /* Look inside the argument pack. */
7418 }
7421 {
7425 /* Extract the next argument from the argument
7426 pack. */
7430 /* Look at the pattern of the pack expansion. */
7433 /* Extract the template parameters from the template
7434 argument. */
7440 /* Verify that we can coerce the template template
7441 parameters from the template argument to the template
7442 parameter. This requires an exact match. */
7444 && !coerce_template_template_parms
7446 targ_parms,
7447 tf_none,
7448 tparm,
7449 targs))
7450 {
7453 }
7454 }
7455 }
7456 }
7458 out:
7462 }
7464 /* Since type attributes aren't mangled, we need to strip them from
7465 template type arguments. */
7467 static tree
7469 {
7479 }
7481 /* And from inside dependent non-type arguments like sizeof(Type). */
7483 static tree
7485 {
7495 }
7497 // A template declaration can be substituted for a constrained
7498 // template template parameter only when the argument is more
7499 // constrained than the parameter.
7500 static bool
7502 {
7505 /* For now, allow constrained template template arguments
7506 and unconstrained template template parameters. */
7512 // If the template parameter is constrained, we need to rewrite its
7513 // constraints in terms of the ARG's template parameters. This ensures
7514 // that all of the template parameter types will have the same depth.
7515 //
7516 // Note that this is only valid when coerce_template_template_parm is
7517 // true for the innermost template parameters of PARM and ARG. In other
7518 // words, because coercion is successful, this conversion will be valid.
7520 {
7527 }
7530 }
7532 // Convert a placeholder argument into a binding to the original
7533 // parameter. The original parameter is saved as the TREE_TYPE of
7534 // ARG.
7537 {
7540 }
7542 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7543 because one of them is dependent. But we need to represent the
7544 conversion for the benefit of cp_tree_equal. */
7546 static tree
7548 {
7549 /* Auto parms get no conversion. */
7552 /* We don't need or want to add this conversion now if we're going to use the
7553 argument for deduction. */
7565 }
7567 /* Convert the indicated template ARG as necessary to match the
7568 indicated template PARM. Returns the converted ARG, or
7569 error_mark_node if the conversion was unsuccessful. Error and
7570 warning messages are issued under control of COMPLAIN. This
7571 conversion is for the Ith parameter in the parameter list. ARGS is
7572 the full set of template arguments deduced so far. */
7574 static tree
7576 tree arg,
7577 tree args,
7578 tsubst_flags_t complain,
7580 tree in_decl)
7581 {
7582 tree orig_arg;
7583 tree val;
7589 /* Trivially convert placeholders. */
7598 {
7599 /* The template argument was the name of some
7600 member function. That's usually
7601 invalid, but static members are OK. In any
7602 case, grab the underlying fields/functions
7603 and issue an error later if required. */
7606 }
7614 /* When determining whether an argument pack expansion is a template,
7615 look at the pattern. */
7619 /* Deal with an injected-class-name used as a template template arg. */
7621 {
7624 {
7634 }
7635 }
7637 is_tmpl_type =
7653 {
7655 {
7659 }
7662 "to refer to a type member of a template parameter, "
7667 typename_type,
7668 complain);
7671 }
7673 {
7675 {
7677 {
7689 else
7692 }
7693 }
7695 }
7697 {
7699 {
7706 else
7709 }
7711 }
7714 /* We already did the appropriate conversion when packing args. */
7717 {
7719 {
7721 /* The number of argument required is not known yet.
7722 Just accept it for now. */
7724 else
7725 {
7727 tree argparm;
7729 /* Strip alias templates that are equivalent to another
7730 template. */
7736 args))
7737 {
7740 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7741 TEMPLATE_DECL. */
7743 {
7748 }
7749 }
7750 else
7751 {
7753 {
7760 }
7763 }
7765 // Check that the constraints are compatible before allowing the
7766 // substitution.
7769 {
7771 {
7777 }
7779 }
7780 }
7781 }
7782 else
7784 /* We only form one instance of each template specialization.
7785 Therefore, if we use a non-canonical variant (i.e., a
7786 typedef), any future messages referring to the type will use
7787 the typedef, which is confusing if those future uses do not
7788 themselves also use the typedef. */
7791 }
7792 else
7793 {
7797 {
7801 }
7802 else
7810 /* We used to call digest_init here. However, digest_init
7811 will report errors, which we don't want when complain
7812 is zero. More importantly, digest_init will try too
7813 hard to convert things: for example, `0' should not be
7814 converted to pointer type at this point according to
7815 the standard. Accepting this is not merely an
7816 extension, since deciding whether or not these
7817 conversions can occur is part of determining which
7818 function template to call, or whether a given explicit
7819 argument specification is valid. */
7821 else
7822 {
7825 }
7835 {
7836 /* Reject template arguments that are references to built-in
7837 functions with no library fallbacks. */
7846 }
7849 {
7850 /* Strip typedefs from the SCOPE_REF. */
7853 complain);
7856 }
7857 }
7860 }
7862 /* Coerces the remaining template arguments in INNER_ARGS (from
7863 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7864 Returns the coerced argument pack. PARM_IDX is the position of this
7865 parameter in the template parameter list. ARGS is the original
7866 template argument list. */
7867 static tree
7870 tree args,
7871 tree inner_args,
7873 tree new_args,
7875 tree in_decl,
7876 tsubst_flags_t complain)
7877 {
7880 tree packed_args;
7881 tree argument_pack;
7888 {
7889 /* When the template parameter is a non-type template parameter pack
7890 or template template parameter pack whose type or template
7891 parameters use parameter packs, we know exactly how many arguments
7892 we are looking for. Build a vector of the instantiated decls for
7893 these template parameters in PACKED_PARMS. */
7894 /* We can't use make_pack_expansion here because it would interpret a
7895 _DECL as a use rather than a declaration. */
7909 /* If we're doing a partial instantiation of a member template,
7910 verify that all of the types used for the non-type
7911 template parameter pack are, in fact, valid for non-type
7912 template parameters. */
7915 {
7918 {
7922 }
7923 /* We don't know how many args we have yet, just
7924 use the unconverted ones for now. */
7926 }
7929 }
7930 /* Check if we have a placeholder pack, which indicates we're
7931 in the context of a introduction list. In that case we want
7932 to match this pack to the single placeholder. */
7936 {
7939 }
7940 else
7943 /* Convert the remaining arguments, which will be a part of the
7944 parameter pack "parm". */
7947 {
7953 {
7954 /* Once we've packed as many args as we have types, stop. */
7958 /* We don't know how many args we have yet, just
7959 use the unconverted ones for now. */
7961 else
7963 }
7966 {
7969 }
7970 else
7973 in_decl);
7977 }
7981 {
7986 }
7991 else
7992 {
7995 }
8002 }
8004 /* Returns the number of pack expansions in the template argument vector
8005 ARGS. */
8007 static int
8009 {
8014 {
8018 }
8020 }
8022 /* Convert all template arguments to their appropriate types, and
8023 return a vector containing the innermost resulting template
8024 arguments. If any error occurs, return error_mark_node. Error and
8025 warning messages are issued under control of COMPLAIN.
8027 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8028 for arguments not specified in ARGS. Otherwise, if
8029 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8030 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8031 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8032 ARGS. */
8034 static tree
8036 tree args,
8037 tree in_decl,
8038 tsubst_flags_t complain,
8041 {
8043 tree orig_inner_args;
8044 tree inner_args;
8045 tree new_args;
8046 tree new_inner_args;
8050 /* When used as a boolean value, indicates whether this is a
8051 variadic template parameter list. Since it's an int, we can also
8052 subtract it from nparms to get the number of non-variadic
8053 parameters. */
8058 /* Likewise for parameters with default arguments. */
8066 /* Determine if there are any parameter packs or default arguments. */
8068 {
8076 }
8079 /* If there are no parameters that follow a parameter pack, we need to
8080 expand any argument packs so that we can deduce a parameter pack from
8081 some non-packed args followed by an argument pack, as in variadic85.C.
8082 If there are such parameters, we need to leave argument packs intact
8083 so the arguments are assigned properly. This can happen when dealing
8084 with a nested class inside a partial specialization of a class
8085 template, as in variadic92.C, or when deducing a template parameter pack
8086 from a sub-declarator, as in variadic114.C. */
8090 /* Count any pack expansion args. */
8096 && require_all_args
8097 && !variadic_args_p
8098 && (!use_default_args
8101 {
8103 {
8105 {
8109 }
8110 else
8117 }
8120 }
8121 /* We can't pass a pack expansion to a non-pack parameter of an alias
8122 template (DR 1430). */
8126 && variadic_args_p
8128 {
8130 {
8132 {
8138 {
8141 "pack expansion argument for non-pack parameter "
8143 else
8145 "pack expansion argument for non-pack parameter "
8149 }
8150 }
8152 found:;
8153 }
8155 }
8157 /* We need to evaluate the template arguments, even though this
8158 template-id may be nested within a "sizeof". */
8167 {
8168 tree arg;
8169 tree parm;
8171 /* Get the Ith template parameter. */
8175 {
8178 }
8180 /* Calculate the next argument. */
8183 else
8188 {
8189 /* Some arguments will be placed in the
8190 template parameter pack PARM. */
8197 {
8198 /* We don't know how many args we have yet, just use the
8199 unconverted (and still packed) ones for now. */
8203 }
8207 /* Store this argument. */
8209 {
8210 lost++;
8211 /* We are done with all of the arguments. */
8213 }
8214 else
8215 {
8218 }
8221 }
8223 {
8225 {
8226 /* "If every valid specialization of a variadic template
8227 requires an empty template parameter pack, the template is
8228 ill-formed, no diagnostic required." So check that the
8229 pattern works with this parameter. */
8234 in_decl);
8236 {
8241 }
8243 /* Recover from missing typename. */
8247 /* We don't know how many args we have yet, just
8248 use the unconverted ones for now. */
8252 }
8253 }
8255 {
8256 /* There must be a default arg in this case. */
8259 /* The position of the first default template argument,
8260 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8261 Record that. */
8265 }
8266 else
8270 {
8273 }
8275 /* This only occurs if there was an error in the template
8276 parameter list itself (which we would already have
8277 reported) that we are trying to recover from, e.g., a class
8278 template with a parameter list such as
8279 template<typename..., typename>. */
8281 else
8287 lost++;
8289 }
8294 {
8296 {
8301 }
8303 }
8313 }
8315 /* Convert all template arguments to their appropriate types, and
8316 return a vector containing the innermost resulting template
8317 arguments. If any error occurs, return error_mark_node. Error and
8318 warning messages are not issued.
8320 Note that no function argument deduction is performed, and default
8321 arguments are used to fill in unspecified arguments. */
8322 tree
8324 {
8326 }
8328 /* Convert all template arguments to their appropriate type, and
8329 instantiate default arguments as needed. This returns a vector
8330 containing the innermost resulting template arguments, or
8331 error_mark_node if unsuccessful. */
8332 tree
8334 tsubst_flags_t complain)
8335 {
8337 }
8339 /* Like coerce_template_parms. If PARMS represents all template
8340 parameters levels, this function returns a vector of vectors
8341 representing all the resulting argument levels. Note that in this
8342 case, only the innermost arguments are coerced because the
8343 outermost ones are supposed to have been coerced already.
8345 Otherwise, if PARMS represents only (the innermost) vector of
8346 parameters, this function returns a vector containing just the
8347 innermost resulting arguments. */
8349 static tree
8351 tree args,
8352 tree in_decl,
8353 tsubst_flags_t complain,
8356 {
8359 tree coerced_args;
8362 {
8364 tree level;
8370 {
8371 tree l;
8375 require_all_args,
8376 use_default_args);
8377 else
8384 }
8385 }
8386 else
8389 require_all_args,
8390 use_default_args);
8392 }
8394 /* Returns 1 if template args OT and NT are equivalent. */
8396 int
8398 {
8407 /* For member templates */
8416 {
8433 }
8437 {
8440 /* Don't treat an alias template specialization with dependent
8441 arguments as equivalent to its underlying type when used as a
8442 template argument; we need them to be distinct so that we
8443 substitute into the specialization arguments at instantiation
8444 time. And aliases can't be equivalent without being ==, so
8445 we don't need to look any deeper.
8447 During partial ordering, however, we need to treat them normally so
8448 that we can order uses of the same alias with different
8449 cv-qualification (79960). */
8453 else
8455 }
8458 else
8459 {
8460 /* Try to treat a template non-type argument that has been converted
8461 to the parameter type as equivalent to one that hasn't yet. */
8474 }
8475 }
8477 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8478 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8479 NEWARG_PTR with the offending arguments if they are non-NULL. */
8481 int
8485 {
8498 {
8503 {
8509 }
8510 }
8512 }
8516 {
8518 }
8520 static void
8522 {
8532 /* We are called both from instantiate_decl, where we've already had a
8533 tinst_level pushed, and instantiate_template, where we haven't.
8534 Compensate. */
8545 else
8554 }
8557 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8558 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8559 documentation for TEMPLATE_ID_EXPR. */
8561 tree
8563 {
8564 tree type;
8572 {
8575 }
8578 {
8580 unknown_type_node,
8582 arglist);
8584 }
8591 }
8593 /* Within the scope of a template class S<T>, the name S gets bound
8594 (in build_self_reference) to a TYPE_DECL for the class, not a
8595 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8596 or one of its enclosing classes, and that type is a template,
8597 return the associated TEMPLATE_DECL. Otherwise, the original
8598 DECL is returned.
8600 Also handle the case when DECL is a TREE_LIST of ambiguous
8601 injected-class-names from different bases. */
8603 tree
8605 {
8609 /* DR 176: A lookup that finds an injected-class-name (10.2
8610 [class.member.lookup]) can result in an ambiguity in certain cases
8611 (for example, if it is found in more than one base class). If all of
8612 the injected-class-names that are found refer to specializations of
8613 the same class template, and if the name is followed by a
8614 template-argument-list, the reference refers to the class template
8615 itself and not a specialization thereof, and is not ambiguous. */
8617 {
8620 {
8626 }
8629 else
8631 }
8637 }
8639 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8640 parameters, find the desired type.
8642 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8644 IN_DECL, if non-NULL, is the template declaration we are trying to
8645 instantiate.
8647 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8648 the class we are looking up.
8650 Issue error and warning messages under control of COMPLAIN.
8652 If the template class is really a local class in a template
8653 function, then the FUNCTION_CONTEXT is the function in which it is
8654 being instantiated.
8656 ??? Note that this function is currently called *twice* for each
8657 template-id: the first time from the parser, while creating the
8658 incomplete type (finish_template_type), and the second type during the
8659 real instantiation (instantiate_template_class). This is surely something
8660 that we want to avoid. It also causes some problems with argument
8661 coercion (see convert_nontype_argument for more information on this). */
8663 static tree
8666 {
8668 tree t;
8671 spec_entry elt;
8672 hashval_t hash;
8675 {
8679 else
8680 {
8687 }
8690 }
8692 {
8695 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8696 an implicit typename for the second A. Deal with it. */
8701 {
8704 }
8705 }
8708 {
8711 }
8713 {
8717 }
8719 {
8722 }
8724 /* Issue an error message if we didn't find a template. */
8726 {
8730 }
8733 /* Make sure it's a user visible template, if it was named by
8734 the user. */
8737 {
8739 {
8743 }
8745 }
8749 /* An alias that just changes the name of a template is equivalent to the
8750 other template, so if any of the arguments are pack expansions, strip
8751 the alias to avoid problems with a pack expansion passed to a non-pack
8752 alias template parameter (DR 1430). */
8757 {
8758 tree parm;
8767 }
8768 else
8769 {
8771 tree gen_tmpl;
8772 tree type_decl;
8780 /* An error occurred while building the template TEMPL, and a
8781 diagnostic has most certainly been emitted for that
8782 already. Let's propagate that error. */
8791 {
8792 /* We've been given an incomplete set of template arguments.
8793 For example, given:
8795 template <class T> struct S1 {
8796 template <class U> struct S2 {};
8797 template <class U> struct S2<U*> {};
8798 };
8800 we will be called with an ARGLIST of `U*', but the
8801 TEMPLATE will be `template <class T> template
8802 <class U> struct S1<T>::S2'. We must fill in the missing
8803 arguments. */
8807 }
8809 /* Now we should have enough arguments. */
8812 /* From here on, we're only interested in the most general
8813 template. */
8815 /* Calculate the BOUND_ARGS. These will be the args that are
8816 actually tsubst'd into the definition to create the
8817 instantiation. */
8819 complain,
8824 /* We were unable to bind the arguments. */
8827 /* In the scope of a template class, explicit references to the
8828 template class refer to the type of the template, not any
8829 instantiation of it. For example, in:
8831 template <class T> class C { void f(C<T>); }
8833 the `C<T>' is just the same as `C'. Outside of the
8834 class, however, such a reference is an instantiation. */
8838 {
8843 }
8845 /* If we already have this specialization, return it. */
8855 /* If the the template's constraints are not satisfied,
8856 then we cannot form a valid type.
8858 Note that the check is deferred until after the hash
8859 lookup. This prevents redundant checks on previously
8860 instantiated specializations. */
8862 {
8864 {
8867 }
8869 }
8873 /* If the deduced arguments are invalid, then the binding
8874 failed. */
8878 complain))
8885 {
8890 }
8900 /* Create the type. */
8902 {
8903 /* The user referred to a specialization of an alias
8904 template represented by GEN_TMPL.
8906 [temp.alias]/2 says:
8908 When a template-id refers to the specialization of an
8909 alias template, it is equivalent to the associated
8910 type obtained by substitution of its
8911 template-arguments for the template-parameters in the
8912 type-id of the alias template. */
8915 /* Note that the call above (by indirectly calling
8916 register_specialization in tsubst_decl) registers the
8917 TYPE_DECL representing the specialization of the alias
8918 template. So next time someone substitutes ARGLIST for
8919 the template parms into the alias template (GEN_TMPL),
8920 she'll get that TYPE_DECL back. */
8924 }
8926 {
8928 {
8939 }
8940 else
8941 {
8942 /* We don't want to call start_enum for this type, since
8943 the values for the enumeration constants may involve
8944 template parameters. And, no one should be interested
8945 in the enumeration constants for such a type. */
8948 }
8952 }
8954 {
8955 /* Lambda closures are regenerated in tsubst_lambda_expr, not
8956 instantiated here. */
8964 /* A local class. Make sure the decl gets registered properly. */
8969 /* This instantiation is another name for the primary
8970 template type. Set the TYPE_CANONICAL field
8971 appropriately. */
8974 /* Some of the template arguments require structural
8975 equality testing, so this template class requires
8976 structural equality testing. */
8978 }
8979 else
8982 /* If we called start_enum or pushtag above, this information
8983 will already be set up. */
8985 {
8992 }
8993 else
8997 {
9003 {
9006 }
9007 }
9011 {
9015 {
9016 tree attributes
9024 }
9025 }
9027 /* Let's consider the explicit specialization of a member
9028 of a class template specialization that is implicitly instantiated,
9029 e.g.:
9030 template<class T>
9031 struct S
9032 {
9033 template<class U> struct M {}; //#0
9034 };
9036 template<>
9037 template<>
9038 struct S<int>::M<char> //#1
9039 {
9040 int i;
9041 };
9042 [temp.expl.spec]/4 says this is valid.
9044 In this case, when we write:
9045 S<int>::M<char> m;
9047 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9048 the one of #0.
9050 When we encounter #1, we want to store the partial instantiation
9051 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9053 For all cases other than this "explicit specialization of member of a
9054 class template", we just want to store the most general template into
9055 the CLASSTYPE_TI_TEMPLATE of M.
9057 This case of "explicit specialization of member of a class template"
9058 only happens when:
9059 1/ the enclosing class is an instantiation of, and therefore not
9060 the same as, the context of the most general template, and
9061 2/ we aren't looking at the partial instantiation itself, i.e.
9062 the innermost arguments are not the same as the innermost parms of
9063 the most general template.
9065 So it's only when 1/ and 2/ happens that we want to use the partial
9066 instantiation of the member template in lieu of its most general
9067 template. */
9071 /* the enclosing class must be an instantiation... */
9074 {
9078 tree partial_inst_args =
9085 use_partial_inst_tmpl =
9086 /*...and we must not be looking at the partial instantiation
9087 itself. */
9089 partial_inst_args);
9090 }
9093 /* This case is easy; there are no member templates involved. */
9095 else
9096 {
9097 /* This is a full instantiation of a member template. Find
9098 the partial instantiation of which this is an instance. */
9100 /* Temporarily reduce by one the number of levels in the ARGLIST
9101 so as to avoid comparing the last set of arguments. */
9105 /* FOUND is either a proper class type, or an alias
9106 template specialization. In the later case, it's a
9107 TYPE_DECL, resulting from the substituting of arguments
9108 for parameters in the TYPE_DECL of the alias template
9109 done earlier. So be careful while getting the template
9110 of FOUND. */
9112 ? found
9116 }
9118 // Build template info for the new specialization.
9127 /* Note this use of the partial instantiation so we can check it
9128 later in maybe_process_partial_specialization. */
9135 /* Now that the type has been registered on the instantiations
9136 list, we set up the enumerators. Because the enumeration
9137 constants may involve the enumeration type itself, we make
9138 sure to register the type first, and then create the
9139 constants. That way, doing tsubst_expr for the enumeration
9140 constants won't result in recursive calls here; we'll find
9141 the instantiation and exit above. */
9145 /* If the type makes use of template parameters, the
9146 code that generates debugging information will crash. */
9149 /* Possibly limit visibility based on template args. */
9156 }
9157 }
9159 /* Wrapper for lookup_template_class_1. */
9161 tree
9164 {
9165 tree ret;
9171 }
9173 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9175 tree
9177 {
9178 /* The type of the expression is NULL_TREE since the template-id could refer
9179 to an explicit or partial specialization. */
9182 /* Except that concepts are always bool. */
9185 }
9187 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9189 tree
9191 {
9195 /* We never want to return a VAR_DECL for a variable concept, since they
9196 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9211 {
9213 {
9216 }
9218 }
9220 /* If a template-id refers to a specialization of a variable
9221 concept, then the expression is true if and only if the
9222 concept's constraints are satisfied by the given template
9223 arguments.
9225 NOTE: This is an extension of Concepts Lite TS that
9226 allows constraints to be used in expressions. */
9228 {
9231 }
9234 }
9236 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9237 TARGS template args, and instantiate it if it's not dependent. */
9239 tree
9241 tsubst_flags_t complain)
9242 {
9245 {
9248 }
9251 }
9253 \f
9254 struct pair_fn_data
9255 {
9256 tree_fn_t fn;
9257 tree_fn_t any_fn;
9259 /* True when we should also visit template parameters that occur in
9260 non-deduced contexts. */
9263 };
9265 /* Called from for_each_template_parm via walk_tree. */
9267 static tree
9269 {
9276 #define WALK_SUBTREE(NODE) \
9277 do \
9278 { \
9279 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9280 pfd->include_nondeduced_p, \
9281 pfd->any_fn); \
9282 if (result) goto out; \
9283 } \
9284 while (0)
9294 {
9298 /* Fall through. */
9304 else
9314 /* Since we're not going to walk subtrees, we have to do this
9315 explicitly here. */
9317 /* Fall through. */
9320 /* Check the return type. */
9323 /* Check the parameter types. Since default arguments are not
9324 instantiated until they are needed, the TYPE_ARG_TYPES may
9325 contain expressions that involve template parameters. But,
9326 no-one should be looking at them yet. And, once they're
9327 instantiated, they don't contain template parameters, so
9328 there's no point in looking at them then, either. */
9329 {
9330 tree parm;
9335 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9336 want walk_tree walking into them itself. */
9338 }
9341 {
9345 }
9362 /* Fall through. */
9374 /* Record template parameters such as `T' inside `TT<T>'. */
9376 /* Fall through. */
9388 /* A template template parameter is encountered. */
9392 /* Already substituted template template parameter */
9397 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9398 partial instantiation. */
9410 /* If there's no type, then this thing must be some expression
9411 involving template parameters. */
9433 }
9435 #undef WALK_SUBTREE
9437 /* We didn't find any template parameters we liked. */
9438 out:
9440 }
9442 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9443 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9444 call FN with the parameter and the DATA.
9445 If FN returns nonzero, the iteration is terminated, and
9446 for_each_template_parm returns 1. Otherwise, the iteration
9447 continues. If FN never returns a nonzero value, the value
9448 returned by for_each_template_parm is 0. If FN is NULL, it is
9449 considered to be the function which always returns 1.
9451 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9452 parameters that occur in non-deduced contexts. When false, only
9453 visits those template parameters that can be deduced. */
9455 static tree
9459 tree_fn_t any_fn)
9460 {
9462 tree result;
9464 /* Set up. */
9470 /* Walk the tree. (Conceptually, we would like to walk without
9471 duplicates, but for_each_template_parm_r recursively calls
9472 for_each_template_parm, so we would need to reorganize a fair
9473 bit to use walk_tree_without_duplicates, so we keep our own
9474 visited list.) */
9477 else
9480 for_each_template_parm_r,
9484 /* Clean up. */
9486 {
9489 }
9492 }
9494 /* Returns true if T depends on any template parameter. */
9496 int
9498 {
9528 else
9529 {
9532 }
9537 }
9539 /* Returns true iff current_function_decl is an incompletely instantiated
9540 template. Useful instead of processing_template_decl because the latter
9541 is set to 0 during instantiate_non_dependent_expr. */
9543 bool
9545 {
9554 }
9556 /* Returns true if T depends on any template parameter with level LEVEL. */
9558 bool
9560 {
9563 }
9565 /* Returns true if the signature of DECL depends on any template parameter from
9566 its enclosing class. */
9568 bool
9570 {
9580 template_parm_outer_level,
9590 }
9592 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9593 ill-formed translation unit, i.e. a variable or function that isn't
9594 usable in a constant expression. */
9598 {
9603 }
9605 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9606 neglectable and instantiated from within an erroneous instantiation. */
9608 static bool
9610 {
9621 }
9629 /* We're starting to instantiate D; record the template instantiation context
9630 for diagnostics and to restore it later. */
9632 bool
9634 {
9636 }
9638 /* We're starting to instantiate D; record the template instantiation context
9639 at LOC for diagnostics and to restore it later. */
9641 bool
9643 {
9647 {
9648 /* Tell error.c not to try to instantiate any templates. */
9651 "template instantiation depth exceeds maximum of %d"
9653 max_tinst_depth);
9655 }
9657 /* If the current instantiation caused problems, don't let it instantiate
9658 anything else. Do allow deduction substitution and decls usable in
9659 constant expressions. */
9663 /* When not -quiet, dump template instantiations other than functions, since
9664 announce_function will take care of those. */
9683 }
9685 /* We're done instantiating this template; return to the instantiation
9686 context. */
9688 void
9690 {
9691 /* Restore the filename and line number stashed away when we started
9692 this instantiation. */
9696 }
9698 /* We're instantiating a deferred template; restore the template
9699 instantiation context in which the instantiation was requested, which
9700 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9702 static tree
9704 {
9716 }
9718 /* Returns the TINST_LEVEL which gives the original instantiation
9719 context. */
9723 {
9729 }
9731 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9732 vector of template arguments, as for tsubst.
9734 Returns an appropriate tsubst'd friend declaration. */
9736 static tree
9738 {
9739 tree new_friend;
9744 /* This was a friend declared with an explicit template
9745 argument list, e.g.:
9747 friend void f<>(T);
9749 to indicate that f was a template instantiation, not a new
9750 function declaration. Now, we have to figure out what
9751 instantiation of what template. */
9752 {
9754 tree new_args;
9755 tree tmpl;
9758 /* Friend functions are looked up in the containing namespace scope.
9759 We must enter that scope, to avoid finding member functions of the
9760 current class with same name. */
9775 tsk_none);
9777 }
9781 /* The NEW_FRIEND will look like an instantiation, to the
9782 compiler, but is not an instantiation from the point of view of
9783 the language. For example, we might have had:
9785 template <class T> struct S {
9786 template <class U> friend void f(T, U);
9787 };
9789 Then, in S<int>, template <class U> void f(int, U) is not an
9790 instantiation of anything. */
9796 {
9800 }
9802 /* The mangled name for the NEW_FRIEND is incorrect. The function
9803 is not a template instantiation and should not be mangled like
9804 one. Therefore, we forget the mangling here; we'll recompute it
9805 later if we need it. */
9807 {
9810 }
9813 {
9814 tree old_decl;
9815 tree new_friend_template_info;
9816 tree new_friend_result_template_info;
9817 tree ns;
9820 /* We must save some information from NEW_FRIEND before calling
9821 duplicate decls since that function will free NEW_FRIEND if
9822 possible. */
9824 new_friend_is_defn =
9829 {
9830 /* This declaration is a `primary' template. */
9833 new_friend_result_template_info
9835 }
9836 else
9839 /* Inside pushdecl_namespace_level, we will push into the
9840 current namespace. However, the friend function should go
9841 into the namespace of the template. */
9851 {
9852 /* This new friend declaration matched an existing
9853 declaration. For example, given:
9855 template <class T> void f(T);
9856 template <class U> class C {
9857 template <class T> friend void f(T) {}
9858 };
9860 the friend declaration actually provides the definition
9861 of `f', once C has been instantiated for some type. So,
9862 old_decl will be the out-of-class template declaration,
9863 while new_friend is the in-class definition.
9865 But, if `f' was called before this point, the
9866 instantiation of `f' will have DECL_TI_ARGS corresponding
9867 to `T' but not to `U', references to which might appear
9868 in the definition of `f'. Previously, the most general
9869 template for an instantiation of `f' was the out-of-class
9870 version; now it is the in-class version. Therefore, we
9871 run through all specialization of `f', adding to their
9872 DECL_TI_ARGS appropriately. In particular, they need a
9873 new set of outer arguments, corresponding to the
9874 arguments for this class instantiation.
9876 The same situation can arise with something like this:
9878 friend void f(int);
9879 template <class T> class C {
9880 friend void f(T) {}
9881 };
9883 when `C<int>' is instantiated. Now, `f(int)' is defined
9884 in the class. */
9887 /* On the other hand, if the in-class declaration does
9888 *not* provide a definition, then we don't want to alter
9889 existing definitions. We can just leave everything
9890 alone. */
9891 ;
9892 else
9893 {
9897 /* Overwrite whatever template info was there before, if
9898 any, with the new template information pertaining to
9899 the declaration. */
9903 {
9904 /* We should have called reregister_specialization in
9905 duplicate_decls. */
9910 /* Instantiate it if the global has already been used. */
9914 }
9915 else
9916 {
9917 tree t;
9919 /* Indicate that the old function template is a partial
9920 instantiation. */
9928 /* Reassign any specializations already in the hash table
9929 to the new more general template, and add the
9930 additional template args. */
9934 {
9936 spec_entry elt;
9948 register_specialization
9951 }
9953 }
9954 }
9956 /* The information from NEW_FRIEND has been merged into OLD_DECL
9957 by duplicate_decls. */
9959 }
9960 }
9961 else
9962 {
9966 /* In the code
9967 template <class T> class C {
9968 template <class U> friend void C1<U>::f (); // case 1
9969 friend void C2<T>::f (); // case 2
9970 };
9971 we only need to make sure CONTEXT is a complete type for
9972 case 2. To distinguish between the two cases, we note that
9973 CONTEXT of case 1 remains dependent type after tsubst while
9974 this isn't true for case 2. */
9984 {
9986 /* do_friend adds the TEMPLATE_DECL for any member friend
9987 template even if it isn't a member template, i.e.
9988 template <class T> friend A<T>::f();
9989 Look through it in that case. */
9993 /* Check to see that the declaration is really present, and,
9994 possibly obtain an improved declaration. */
9999 }
10000 }
10003 }
10005 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10006 template arguments, as for tsubst.
10008 Returns an appropriate tsubst'd friend type or error_mark_node on
10009 failure. */
10011 static tree
10013 {
10014 tree tmpl;
10017 {
10020 }
10025 else
10033 {
10034 /* The friend template has already been declared. Just
10035 check to see that the declarations match, and install any new
10036 default parameters. We must tsubst the default parameters,
10037 of course. We only need the innermost template parameters
10038 because that is all that redeclare_class_template will look
10039 at. */
10042 {
10050 }
10051 }
10052 else
10053 {
10054 /* The friend template has not already been declared. In this
10055 case, the instantiation of the template class will cause the
10056 injection of this template into the namespace scope. */
10060 {
10061 /* The new TMPL is not an instantiation of anything, so we
10062 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10063 for the new type because that is supposed to be the
10064 corresponding template decl, i.e., TMPL. */
10071 /* It is hidden. */
10076 /* Inject this template into the enclosing namspace scope. */
10078 }
10079 }
10083 else
10087 }
10089 /* Returns zero if TYPE cannot be completed later due to circularity.
10090 Otherwise returns one. */
10092 static int
10094 {
10104 else
10106 }
10111 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10112 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10114 static tree
10117 {
10126 {
10133 clauses
10137 else
10139 }
10140 /* If the first attribute argument is an identifier, don't
10141 pass it through tsubst. Attributes like mode, format,
10142 cleanup and several target specific attributes expect it
10143 unmodified. */
10145 {
10146 tree chain
10151 }
10153 {
10154 /* An attribute pack expansion. */
10163 {
10167 }
10169 }
10170 else
10177 }
10179 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10180 unchanged or a new TREE_LIST chain. */
10182 static tree
10185 {
10190 {
10194 }
10198 {
10201 {
10204 {
10206 do
10211 }
10212 }
10214 }
10217 }
10219 /* Apply any attributes which had to be deferred until instantiation
10220 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10221 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10223 static void
10226 {
10228 tree t;
10235 {
10239 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10240 to our attributes parameter. */
10242 }
10243 else
10244 {
10246 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10247 lookup_template_class_1, and should be preserved. */
10251 }
10255 {
10259 }
10263 {
10268 {
10271 {
10275 do
10278 }
10279 else
10281 }
10284 }
10285 }
10287 /* Perform (or defer) access check for typedefs that were referenced
10288 from within the template TMPL code.
10289 This is a subroutine of instantiate_decl and instantiate_class_template.
10290 TMPL is the template to consider and TARGS is the list of arguments of
10291 that template. */
10293 static void
10295 {
10296 location_t saved_location;
10307 {
10319 /* Make access check error messages point to the location
10320 of the use of the typedef. */
10324 tf_warning_or_error);
10325 }
10327 }
10329 static tree
10331 {
10333 tree typedecl;
10334 tree pbinfo;
10335 tree base_list;
10337 tree fn_context;
10346 /* Figure out which template is being instantiated. */
10350 /* Determine what specialization of the original template to
10351 instantiate. */
10354 {
10357 }
10359 {
10360 /* This TYPE is actually an instantiation of a partial
10361 specialization. We replace the innermost set of ARGS with
10362 the arguments appropriate for substitution. For example,
10363 given:
10365 template <class T> struct S {};
10366 template <class T> struct S<T*> {};
10368 and supposing that we are instantiating S<int*>, ARGS will
10369 presently be {int*} -- but we need {int}. */
10372 }
10373 else
10374 {
10377 }
10379 /* If the template we're instantiating is incomplete, then clearly
10380 there's nothing we can do. */
10384 /* If we've recursively instantiated too many templates, stop. */
10388 /* Now we're really doing the instantiation. Mark the type as in
10389 the process of being defined. */
10392 /* We may be in the middle of deferred access check. Disable
10393 it now. */
10400 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10405 else
10406 {
10409 }
10410 /* Use #pragma pack from the template context. */
10416 /* Set the input location to the most specialized template definition.
10417 This is needed if tsubsting causes an error. */
10429 {
10432 /* Adjust visibility for template arguments. */
10434 }
10440 /* We should never instantiate a nested class before its enclosing
10441 class; we need to look up the nested class by name before we can
10442 instantiate it, and that lookup should instantiate the enclosing
10443 class. */
10449 {
10450 tree pbase_binfo;
10451 tree pushed_scope;
10454 /* We must enter the scope containing the type, as that is where
10455 the accessibility of types named in dependent bases are
10456 looked up from. */
10459 /* Substitute into each of the bases to determine the actual
10460 basetypes. */
10462 {
10463 tree base;
10469 {
10470 expanded_bases =
10477 }
10480 {
10482 /* Extract the already-expanded base class. */
10484 else
10485 /* Substitute to figure out the base class. */
10487 NULL_TREE);
10495 }
10496 }
10498 /* The list is now in reverse order; correct that. */
10503 }
10504 /* Now call xref_basetypes to set up all the base-class
10505 information. */
10513 /* Now that our base classes are set up, enter the scope of the
10514 class, so that name lookups into base classes, etc. will work
10515 correctly. This is precisely analogous to what we do in
10516 begin_class_definition when defining an ordinary non-template
10517 class, except we also need to push the enclosing classes. */
10520 /* Now members are processed in the order of declaration. */
10523 {
10527 {
10529 {
10530 /* Build new CLASSTYPE_NESTED_UTDS. */
10532 tree newtag;
10538 /* If the member is a class template, then -- even after
10539 substitution -- there may be dependent types in the
10540 template argument list for the class. We increment
10541 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10542 that function will assume that no types are dependent
10543 when outside of a template. */
10553 {
10557 /* Unfortunately, lookup_template_class sets
10558 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10559 instantiation (i.e., for the type of a member
10560 template class nested within a template class.)
10561 This behavior is required for
10562 maybe_process_partial_specialization to work
10563 correctly, but is not accurate in this case;
10564 the TAG is not an instantiation of anything.
10565 (The corresponding TEMPLATE_DECL is an
10566 instantiation, but the TYPE is not.) */
10569 /* Now, we call pushtag to put this NEWTAG into the scope of
10570 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10571 pushtag calling push_template_decl. We don't have to do
10572 this for enums because it will already have been done in
10573 tsubst_enum. */
10577 }
10578 }
10580 {
10581 tree r;
10590 /* Instantiate members marked with attribute used. */
10596 }
10599 /* A closure type for a lambda in a default argument for a
10600 member template. Ignore it; it will be instantiated with
10602 else
10603 {
10604 /* Build new TYPE_FIELDS. */
10606 {
10607 tree condition;
10610 condition =
10620 }
10622 {
10623 tree r;
10627 /* The file and line for this declaration, to
10628 assist in error message reporting. Since we
10629 called push_tinst_level above, we don't need to
10630 restore these. */
10640 {
10641 /* A capture pack became multiple fields. */
10644 }
10647 {
10651 {
10652 /* In [temp.inst]:
10654 [t]he initialization (and any associated
10655 side-effects) of a static data member does
10656 not occur unless the static data member is
10657 itself used in a way that requires the
10658 definition of the static data member to
10659 exist.
10661 Therefore, we do not substitute into the
10662 initialized for the static data member here. */
10663 finish_static_data_member_decl
10669 /* Instantiate members marked with attribute used. */
10672 }
10674 {
10675 /* Determine whether R has a valid type and can be
10676 completed later. If R is invalid, then its type
10677 is replaced by error_mark_node. */
10683 {
10684 /* If R's type couldn't be completed and
10685 it isn't a flexible array member (whose
10686 type is incomplete by definition) give
10687 an error. */
10690 }
10691 }
10693 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10694 such a thing will already have been added to the field
10695 list by tsubst_enum in finish_member_declaration in the
10696 CLASSTYPE_NESTED_UTDS case above. */
10700 {
10703 }
10704 }
10705 }
10706 }
10707 }
10708 else
10709 {
10712 {
10713 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10719 {
10720 /* template <class T> friend class C; */
10723 }
10725 {
10726 /* template <class T> friend class C::D; */
10732 }
10735 {
10736 /* This could be either
10738 friend class T::C;
10740 when dependent_type_p is false or
10742 template <class U> friend class T::C;
10744 otherwise. */
10745 /* Bump processing_template_decl in case this is something like
10746 template <class T> friend struct A<T>::B. */
10753 }
10757 {
10758 /* friend class C;
10760 where C hasn't been declared yet. Let's lookup name
10761 from namespace scope directly, bypassing any name that
10762 come from dependent base class. */
10765 /* The call to xref_tag_from_type does injection for friend
10766 classes. */
10768 friend_type =
10772 }
10774 /* friend class C<T>; */
10777 /* Otherwise it's
10779 friend class C;
10781 where C is already declared or
10783 friend class C<int>;
10785 We don't have to do anything in these cases. */
10788 /* Trick make_friend_class into realizing that the friend
10789 we're adding is a template, not an ordinary class. It's
10790 important that we use make_friend_class since it will
10791 perform some error-checking and output cross-reference
10792 information. */
10800 }
10801 else
10802 {
10803 /* Build new DECL_FRIENDLIST. */
10804 tree r;
10806 /* The file and line for this declaration, to
10807 assist in error message reporting. Since we
10808 called push_tinst_level above, we don't need to
10809 restore these. */
10813 {
10816 }
10821 {
10824 }
10825 }
10826 }
10827 }
10830 {
10831 /* Restore these before substituting into the lambda capture
10832 initializers. */
10835 }
10838 {
10841 {
10847 {
10848 /* Set function_depth to avoid garbage collection. */
10852 }
10854 /* We need to instantiate the capture list from the template
10855 after we've instantiated the closure members, but before we
10856 consider adding the conversion op. Also keep any captures
10857 that may have been added during instantiation of the op(). */
10859 tree tmpl_cap
10868 }
10869 else
10871 }
10873 /* Set the file and line number information to whatever is given for
10874 the class itself. This puts error messages involving generated
10875 implicit functions at a predictable point, and the same point
10876 that would be used for non-template classes. */
10883 /* We don't instantiate default arguments for member functions. 14.7.1:
10885 The implicit instantiation of a class template specialization causes
10886 the implicit instantiation of the declarations, but not of the
10887 definitions or default arguments, of the class member functions,
10888 member classes, static data members and member templates.... */
10890 /* Some typedefs referenced from within the template code need to be access
10891 checked at template instantiation time, i.e now. These types were
10892 added to the template at parsing time. Let's get those and perform
10893 the access checks then. */
10903 /* The vtable for a template class can be emitted in any translation
10904 unit in which the class is instantiated. When there is no key
10905 method, however, finish_struct_1 will already have added TYPE to
10906 the keyed_classes. */
10911 }
10913 /* Wrapper for instantiate_class_template_1. */
10915 tree
10917 {
10918 tree ret;
10923 }
10925 static tree
10927 {
10928 tree r;
10934 else
10935 {
10942 }
10944 }
10946 /* Given a function parameter pack TMPL_PARM and some function parameters
10947 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10948 and set *SPEC_P to point at the next point in the list. */
10950 tree
10952 {
10953 /* Collect all of the extra "packed" parameters into an
10954 argument pack. */
10955 tree parmvec;
10965 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10969 {
10974 }
10976 /* Build the argument packs. */
10981 }
10983 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10984 NONTYPE_ARGUMENT_PACK. */
10986 static tree
10988 {
10990 }
10992 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10993 pack expansion with no extra args, 2 if it has extra args, or 0
10994 if it is not a pack expansion. */
10996 static int
10998 {
11004 /* A decl pack is itself an expansion. */
11011 }
11014 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11016 static tree
11018 {
11025 }
11027 /* This is a subroutine of tsubst_pack_expansion.
11029 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11030 mechanism to store the (non complete list of) arguments of the
11031 substitution and return a non substituted pack expansion, in order
11032 to wait for when we have enough arguments to really perform the
11033 substitution. */
11035 static bool
11039 {
11040 /* If one pack has an expansion and another pack has a normal
11041 argument or if one pack has an empty argument and an another
11042 one hasn't then tsubst_pack_expansion cannot perform the
11043 substitution and need to fall back on the
11044 PACK_EXPANSION_EXTRA mechanism. */
11052 {
11055 parm_pack;
11057 {
11062 /* We can't substitute a pack expansion with extra args into
11063 our pattern. */
11067 else
11069 }
11073 }
11075 }
11077 /* [temp.variadic]/6 says that:
11079 The instantiation of a pack expansion [...]
11080 produces a list E1,E2, ..., En, where N is the number of elements
11081 in the pack expansion parameters.
11083 This subroutine of tsubst_pack_expansion produces one of these Ei.
11085 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11086 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11087 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11088 INDEX is the index 'i' of the element Ei to produce. ARGS,
11089 COMPLAIN, and IN_DECL are the same parameters as for the
11090 tsubst_pack_expansion function.
11092 The function returns the resulting Ei upon successful completion,
11093 or error_mark_node.
11095 Note that this function possibly modifies the ARGS parameter, so
11096 it's the responsibility of the caller to restore it. */
11098 static tree
11100 tree parm_packs,
11102 tree args /* This parm gets
11104 tsubst_flags_t complain,
11105 tree in_decl)
11106 {
11107 tree t;
11110 /* For each parameter pack, change the substitution of the parameter
11111 pack to the ith argument in its argument pack, then expand the
11112 pattern. */
11114 {
11119 ith_elem_is_expansion |=
11122 /* Select the Ith argument from the pack. */
11125 {
11127 {
11132 }
11133 else
11135 }
11136 else
11137 {
11142 {
11144 /* Update the corresponding argument. */
11146 }
11147 else
11148 /* Re-use the ARGUMENT_PACK_SELECT. */
11150 }
11152 }
11154 /* Substitute into the PATTERN with the (possibly altered)
11155 arguments. */
11157 /* Expanding a fixed parameter pack from
11158 coerce_template_parameter_pack. */
11163 {
11166 else
11169 }
11173 else
11176 /* If the Ith argument pack element is a pack expansion, then
11177 the Ith element resulting from the substituting is going to
11178 be a pack expansion as well. */
11183 }
11185 /* When the unexpanded parameter pack in a fold expression expands to an empty
11186 sequence, the value of the expression is as follows; the program is
11187 ill-formed if the operator is not listed in this table.
11189 && true
11190 || false
11191 , void() */
11193 tree
11195 {
11199 {
11208 }
11214 }
11216 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11217 form an expression that combines the two terms using the
11218 operator of T. */
11220 static tree
11222 {
11226 // Handle compound assignment operators.
11231 {
11241 complain);
11242 }
11243 }
11245 /* Substitute ARGS into the pack of a fold expression T. */
11249 {
11251 }
11253 /* Substitute ARGS into the pack of a fold expression T. */
11257 {
11259 }
11261 /* Expand a PACK of arguments into a grouped as left fold.
11262 Given a pack containing elements A0, A1, ..., An and an
11263 operator @, this builds the expression:
11265 ((A0 @ A1) @ A2) ... @ An
11267 Note that PACK must not be empty.
11269 The operator is defined by the original fold expression T. */
11271 static tree
11273 {
11276 {
11279 }
11281 }
11283 /* Substitute into a unary left fold expression. */
11285 static tree
11287 tree in_decl)
11288 {
11293 {
11297 }
11300 else
11302 }
11304 /* Substitute into a binary left fold expression.
11306 Do ths by building a single (non-empty) vector of argumnts and
11307 building the expression from those elements. */
11309 static tree
11311 tree in_decl)
11312 {
11321 {
11326 }
11334 }
11336 /* Expand a PACK of arguments into a grouped as right fold.
11337 Given a pack containing elementns A0, A1, ..., and an
11338 operator @, this builds the expression:
11340 A0@ ... (An-2 @ (An-1 @ An))
11342 Note that PACK must not be empty.
11344 The operator is defined by the original fold expression T. */
11346 tree
11348 {
11349 // Build the expression.
11353 {
11356 }
11358 }
11360 /* Substitute into a unary right fold expression. */
11362 static tree
11364 tree in_decl)
11365 {
11370 {
11374 }
11377 else
11379 }
11381 /* Substitute into a binary right fold expression.
11383 Do ths by building a single (non-empty) vector of arguments and
11384 building the expression from those elements. */
11386 static tree
11388 tree in_decl)
11389 {
11398 {
11403 }
11412 }
11415 /* Substitute ARGS into T, which is an pack expansion
11416 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11417 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11418 (if only a partial substitution could be performed) or
11419 ERROR_MARK_NODE if there was an error. */
11420 tree
11422 tree in_decl)
11423 {
11424 tree pattern;
11429 tree result;
11437 /* Add in any args remembered from an earlier partial instantiation. */
11442 /* Determine the argument packs that will instantiate the parameter
11443 packs used in the expansion expression. While we're at it,
11444 compute the number of arguments to be expanded and make sure it
11445 is consistent. */
11448 {
11455 {
11460 else
11463 }
11465 {
11466 /* ??? Support use in other patterns. */
11470 }
11472 {
11473 /* We know we have correct local_specializations if this
11474 expansion is at function scope, or if we're dealing with a
11475 local parameter in a requires expression; for the latter,
11476 tsubst_requires_expr set it up appropriately. */
11479 else
11480 /* We can't rely on local_specializations for a parameter
11481 name used later in a function declaration (such as in a
11482 late-specified return type). Even if it exists, it might
11483 have the wrong value for a recursive call. */
11487 {
11488 /* This parameter pack was used in an unevaluated context. Just
11489 make a dummy decl, since it's only used for its type. */
11492 /* Partial instantiation of the parm_pack, we can't build
11493 up an argument pack yet. */
11495 else
11497 }
11499 /* This argument pack isn't fully instantiated yet. We set this
11500 flag rather than clear arg_pack because we do want to do the
11501 optimization below, and we don't want to substitute directly
11502 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11503 where it isn't expected). */
11505 }
11508 else
11509 {
11515 }
11522 /* This can only happen if we forget to expand an argument
11523 pack somewhere else. Just return an error, silently. */
11524 {
11528 }
11531 {
11535 /* Don't bother trying to do a partial substitution with
11536 incomplete packs; we'll try again after deduction. */
11544 {
11549 pattern);
11550 else
11552 pattern);
11554 }
11556 /* Keep track of the parameter packs and their corresponding
11557 argument packs. */
11560 }
11561 else
11562 {
11563 /* We can't substitute for this parameter pack. We use a flag as
11564 well as the missing_level counter because function parameter
11565 packs don't have a level. */
11568 }
11569 }
11571 /* If the expansion is just T..., return the matching argument pack, unless
11572 we need to call convert_from_reference on all the elements. This is an
11573 important optimization; see c++/68422. */
11576 {
11579 /* If the argument pack is a single pack expansion, pull it out. */
11584 /* Types need no adjustment, nor does sizeof..., and if we still have
11585 some pack expansion args we won't do anything yet. */
11590 /* Also optimize expression pack expansions if we can tell that the
11591 elements won't have reference type. */
11597 /* Otherwise use the normal path so we get convert_from_reference. */
11598 }
11600 /* We cannot expand this expansion expression, because we don't have
11601 all of the argument packs we need. */
11604 {
11605 /* We got some full packs, but we can't substitute them in until we
11606 have values for all the packs. So remember these until then. */
11611 }
11613 {
11614 /* There were no real arguments, we're just replacing a parameter
11615 pack with another version of itself. Substitute into the
11616 pattern and return a PACK_EXPANSION_*. The caller will need to
11617 deal with that. */
11621 else
11625 }
11630 {
11631 /* We're in a late-specified return type, so create our own local
11632 specializations map; the current map is either NULL or (in the
11633 case of recursive unification) might have bindings that we don't
11634 want to use or alter. */
11637 }
11639 /* For each argument in each argument pack, substitute into the
11640 pattern. */
11644 {
11646 i,
11648 in_decl);
11651 {
11654 }
11655 }
11657 /* Update ARGS to restore the substitution from parameter packs to
11658 their argument packs. */
11660 {
11666 else
11667 {
11675 /* Update the corresponding argument. */
11679 else
11681 }
11682 }
11685 {
11688 }
11690 /* If the dependent pack arguments were such that we end up with only a
11691 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11697 }
11699 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11700 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11701 parameter packs; all parms generated from a function parameter pack will
11702 have the same DECL_PARM_INDEX. */
11704 tree
11706 {
11708 tree patparm;
11711 {
11717 }
11718 else
11719 {
11724 }
11727 }
11729 /* Make an argument pack out of the TREE_VEC VEC. */
11731 static tree
11733 {
11734 tree pack;
11738 else
11739 {
11742 }
11745 }
11747 /* Return an exact copy of template args T that can be modified
11748 independently. */
11750 static tree
11752 {
11760 {
11765 }
11771 }
11773 /* Substitute ARGS into the vector or list of template arguments T. */
11775 static tree
11777 {
11789 {
11791 tree new_arg;
11796 {
11797 /* Substitute into an expansion expression. */
11801 /* Add to the expanded length adjustment the number of
11802 expanded arguments. We subtract one from this
11803 measurement, because the argument pack expression
11804 itself is already counted as 1 in
11805 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11806 the argument pack is empty. */
11808 }
11810 {
11811 /* Substitute into each of the arguments. */
11820 else
11825 }
11826 else
11835 }
11840 /* Make space for the expanded arguments coming from template
11841 argument packs. */
11843 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11844 arguments for a member template.
11845 In that case each TREE_VEC in ORIG_T represents a level of template
11846 arguments, and ORIG_T won't carry any non defaulted argument count.
11847 It will rather be the nested TREE_VECs that will carry one.
11848 In other words, ORIG_T carries a non defaulted argument count only
11849 if it doesn't contain any nested TREE_VEC. */
11851 {
11855 }
11857 {
11861 {
11864 /* Now expand the template argument pack "in place". */
11867 }
11868 else
11869 {
11871 out++;
11872 }
11873 }
11876 }
11878 /* Substitute ARGS into one level PARMS of template parameters. */
11880 static tree
11882 {
11889 {
11897 }
11900 }
11902 /* Return the result of substituting ARGS into the template parameters
11903 given by PARMS. If there are m levels of ARGS and m + n levels of
11904 PARMS, then the result will contain n levels of PARMS. For
11905 example, if PARMS is `template <class T> template <class U>
11906 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11907 result will be `template <int*, double, class V>'. */
11909 static tree
11911 {
11915 /* When substituting into a template, we must set
11916 PROCESSING_TEMPLATE_DECL as the template parameters may be
11917 dependent if they are based on one-another, and the dependency
11918 predicates are short-circuit outside of templates. */
11925 {
11932 }
11937 }
11939 /* Return the result of substituting ARGS into one template parameter
11940 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11941 parameter and which TREE_PURPOSE is the default argument of the
11942 template parameter. */
11944 static tree
11946 {
11967 }
11969 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11970 type T. If T is not an aggregate or enumeration type, it is
11971 handled as if by tsubst. IN_DECL is as for tsubst. If
11972 ENTERING_SCOPE is nonzero, T is the context for a template which
11973 we are presently tsubst'ing. Return the substituted value. */
11975 static tree
11977 tree args,
11978 tsubst_flags_t complain,
11979 tree in_decl,
11981 {
11986 {
11991 /* Fall through. */
11995 {
11996 tree argvec;
11997 tree context;
11998 tree r;
12002 /* In "sizeof(X<I>)" we need to evaluate "I". */
12008 /* First, determine the context for the type we are looking
12009 up. */
12012 {
12015 /* If context is a nested class inside a class template,
12016 it may still need to be instantiated (c++/33959). */
12018 }
12020 /* Then, figure out what arguments are appropriate for the
12021 type we are trying to find. For example, given:
12023 template <class T> struct S;
12024 template <class T, class U> void f(T, U) { S<U> su; }
12026 and supposing that we are instantiating f<int, double>,
12027 then our ARGS will be {int, double}, but, when looking up
12028 S we only want {double}. */
12033 else
12034 {
12038 }
12044 }
12045 else
12046 /* This is not a template type, so there's nothing to do. */
12051 }
12052 }
12056 /* Substitute into the default argument ARG (a default argument for
12057 FN), which has the indicated TYPE. */
12059 tree
12061 tsubst_flags_t complain)
12062 {
12067 /* This can happen in invalid code. */
12082 /* This default argument came from a template. Instantiate the
12083 default argument here, not in tsubst. In the case of
12084 something like:
12086 template <class T>
12087 struct S {
12088 static T t();
12089 void f(T = t());
12090 };
12092 we must be careful to do name lookup in the scope of S<T>,
12093 rather than in the current class. */
12095 /* The "this" pointer is not valid in a default argument. */
12097 {
12102 }
12107 /* The default argument expression may cause implicitly defined
12108 member functions to be synthesized, which will result in garbage
12109 collection. We must treat this situation as if we were within
12110 the body of function so as to avoid collecting live data on the
12111 stack. */
12121 /* Restore the "this" pointer. */
12123 {
12126 }
12133 /* Make sure the default argument is reasonable. */
12139 {
12143 }
12146 }
12148 /* Substitute into all the default arguments for FN. */
12150 static void
12152 {
12153 tree arg;
12154 tree tmpl_args;
12158 /* If this function is not yet instantiated, we certainly don't need
12159 its default arguments. */
12162 /* Don't do this again for clones. */
12168 arg;
12174 complain);
12175 }
12177 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12179 static tree
12181 tree lambda_fntype)
12182 {
12187 /* Nobody should be tsubst'ing into non-template functions. */
12191 {
12192 /* If T is not dependent, just return it. */
12196 /* Calculate the most general template of which R is a
12197 specialization. */
12200 /* We're substituting a lambda function under tsubst_lambda_expr but not
12201 directly from it; find the matching function we're already inside.
12202 But don't do this if T is a generic lambda with a single level of
12203 template parms, as in that case we're doing a normal instantiation. */
12209 /* Calculate the complete set of arguments used to
12210 specialize R. */
12212 (DECL_TEMPLATE_RESULT
12218 /* Check to see if we already have this specialization. */
12220 {
12224 }
12226 /* We can see more levels of arguments than parameters if
12227 there was a specialization of a member template, like
12228 this:
12230 template <class T> struct S { template <class U> void f(); }
12231 template <> template <class U> void S<int>::f(U);
12233 Here, we'll be substituting into the specialization,
12234 because that's where we can find the code we actually
12235 want to generate, but we'll have enough arguments for
12236 the most general template.
12238 We also deal with the peculiar case:
12240 template <class T> struct S {
12241 template <class U> friend void f();
12242 };
12243 template <class U> void f() {}
12244 template S<int>;
12245 template void f<double>();
12247 Here, the ARGS for the instantiation of will be {int,
12248 double}. But, we only need as many ARGS as there are
12249 levels of template parameters in CODE_PATTERN. We are
12250 careful not to get fooled into reducing the ARGS in
12251 situations like:
12253 template <class T> struct S { template <class U> void f(U); }
12254 template <class T> template <> void S<T>::f(int) {}
12256 which we can spot because the pattern will be a
12257 specialization in this case. */
12264 }
12265 else
12266 {
12267 /* This special case arises when we have something like this:
12269 template <class T> struct S {
12270 friend void f<int>(int, double);
12271 };
12273 Here, the DECL_TI_TEMPLATE for the friend declaration
12274 will be an IDENTIFIER_NODE. We are being called from
12275 tsubst_friend_function, and we want only to create a
12276 new decl (R) with appropriate types so that we can call
12277 determine_specialization. */
12280 }
12297 /* If we hit excessive deduction depth, the type is bogus even if
12298 it isn't error_mark_node, so don't build a decl. */
12302 /* We do NOT check for matching decls pushed separately at this
12303 point, as they may not represent instantiations of this
12304 template, and in any case are considered separate under the
12305 discrete model. */
12309 /* Clear out the mangled name and RTL for the instantiation. */
12312 /* Leave DECL_INITIAL set on deleted instantiations. */
12317 /* OpenMP UDRs have the only argument a reference to the declared
12318 type. We want to diagnose if the declared type is a reference,
12319 which is invalid, but as references to references are usually
12320 quietly merged, diagnose it here. */
12322 {
12323 tree argtype
12328 "reference type %qT in "
12332 argtype);
12333 }
12336 /* Type-conversion operator. Reconstruct the name, in
12337 case it's the name of one of the template's parameters. */
12347 {
12351 }
12358 /* If this is an instantiation of a function with internal
12359 linkage, we already know what object file linkage will be
12360 assigned to the instantiation. */
12369 /* We'll re-clone as appropriate in instantiate_template. */
12372 /* If we aren't complaining now, return on error before we register
12373 the specialization so that we'll complain eventually. */
12379 /* When instantiating a constrained member, substitute
12380 into the constraints to create a new constraint. */
12383 {
12386 }
12388 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12389 this in the special friend case mentioned above where
12390 GEN_TMPL is NULL. */
12392 {
12397 tree new_r
12400 /* We instantiated this while substituting into
12401 the type earlier (template/friend54.C). */
12404 /* We're not supposed to instantiate default arguments
12405 until they are called, for a template. But, for a
12406 declaration like:
12408 template <class T> void f ()
12409 { extern void g(int i = T()); }
12411 we should do the substitution when the template is
12412 instantiated. We handle the member function case in
12413 instantiate_class_template since the default arguments
12414 might refer to other members of the class. */
12419 }
12420 else
12423 /* Copy the list of befriending classes. */
12427 {
12431 }
12434 {
12438 /* If this is an instantiation of a member template, clone it.
12439 If it isn't, that'll be handled by
12440 clone_constructors_and_destructors. */
12443 }
12454 /* Possibly limit visibility based on template args. */
12457 {
12461 }
12470 }
12472 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12474 static tree
12476 tree lambda_fntype)
12477 {
12478 /* We can get here when processing a member function template,
12479 member class template, or template template parameter. */
12482 tree spec;
12483 tree tmpl_args;
12484 tree full_args;
12485 tree r;
12489 {
12490 /* Template template parameter is treated here. */
12494 /* If we get a real template back, return it. This can happen in
12495 the context of most_specialized_partial_spec. */
12498 else
12499 /* The new TEMPLATE_DECL was built in
12500 reduce_template_parm_level. */
12503 }
12506 {
12507 /* We might already have an instance of this template.
12508 The ARGS are for the surrounding class type, so the
12509 full args contain the tsubst'd args for the context,
12510 plus the innermost args from the template decl. */
12514 /* Because this is a template, the arguments will still be
12515 dependent, even after substitution. If
12516 PROCESSING_TEMPLATE_DECL is not set, the dependency
12517 predicates will short-circuit. */
12525 /* If this is a default template template argument,
12526 tsubst might not have changed anything. */
12534 }
12536 /* Make a new template decl. It will be similar to the
12537 original, but will record the current template arguments.
12538 We also create a new function declaration, which is just
12539 like the old one, but points to this new template, rather
12540 than the old one. */
12545 // Build new template info linking to the original template decl.
12547 {
12550 }
12551 else
12554 /* The template parameters for this new template are all the
12555 template parameters for the old template, except the
12556 outermost level of parameters. */
12559 complain);
12563 {
12564 tree new_type;
12572 /* For a partial specialization, we need to keep pointing to
12573 the primary template. */
12579 }
12580 else
12581 {
12582 tree new_decl;
12586 else
12596 {
12599 }
12600 else
12601 {
12604 }
12605 }
12615 /* Record this non-type partial instantiation. */
12621 }
12623 /* True if FN is the op() for a lambda in an uninstantiated template. */
12625 bool
12627 {
12632 }
12634 /* We're instantiating a variable from template function TCTX. Return the
12635 corresponding current enclosing scope. This gets complicated because lambda
12636 functions in templates are regenerated rather than instantiated, but generic
12637 lambda functions are subsequently instantiated. */
12639 static tree
12641 {
12650 {
12663 }
12665 }
12667 /* Substitute the ARGS into the T, which is a _DECL. Return the
12668 result of the substitution. Issue error and warning messages under
12669 control of COMPLAIN. */
12671 static tree
12673 {
12674 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12675 location_t saved_loc;
12680 /* Set the filename and linenumber to improve error-reporting. */
12685 {
12695 {
12703 {
12704 /* If there is a local specialization that isn't a
12705 parameter pack, it means that we're doing a "simple"
12706 substitution from inside tsubst_pack_expansion. Just
12707 return the local specialization (which will be a single
12708 parm). */
12715 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12716 the parameters in this function parameter pack. */
12720 {
12723 /* Zero-length parameter packs are boring. Just substitute
12724 into the chain. */
12728 }
12729 else
12730 {
12731 /* All we did was update the type. Make a note of that. */
12734 }
12735 }
12737 /* Loop through all of the parameters we'll build. When T is
12738 a function parameter pack, LEN is the number of expanded
12739 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12742 {
12749 /* We're on the Ith parameter of the function parameter
12750 pack. */
12751 {
12752 /* Get the Ith type. */
12755 /* Rename the parameter to include the index. */
12758 }
12760 /* We're dealing with a normal parameter. */
12768 {
12771 else
12774 }
12784 /* Keep track of the first new parameter we
12785 generate. That's what will be returned to the
12786 caller. */
12790 /* Build a proper chain of parameters when substituting
12791 into a function parameter pack. */
12794 }
12796 /* If cp_unevaluated_operand is set, we're just looking for a
12797 single dummy parameter, so don't keep going. */
12802 /* FIRST_R contains the start of the chain we've built. */
12804 }
12808 {
12815 {
12816 /* This field is a lambda capture pack. Return a TREE_VEC of
12817 the expanded fields to instantiate_class_template_1 and
12818 store them in the specializations hash table as a
12819 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12823 {
12826 }
12827 else
12828 {
12829 /* All we did was update the type. Make a note of that. */
12832 }
12833 }
12836 {
12839 {
12843 }
12853 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12854 number of bits. */
12860 {
12861 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12862 NSDMI in perform_member_init. Still set DECL_INITIAL
12863 so that we know there is one. */
12868 }
12869 /* We don't have to set DECL_CONTEXT here; it is set by
12870 finish_member_declaration. */
12878 }
12881 {
12886 }
12887 }
12891 /* We reach here only for member using decls. We also need to check
12892 uses_template_parms because DECL_DEPENDENT_P is not set for a
12893 using-declaration that designates a member of the current
12894 instantiation (c++/53549). */
12897 {
12901 {
12906 {
12910 {
12913 }
12914 else
12915 {
12918 }
12920 }
12921 }
12922 else
12923 {
12929 else
12930 {
12933 }
12934 }
12935 }
12936 else
12937 {
12940 }
12945 {
12948 tree spec;
12950 tree ctx;
12959 {
12960 /* If this is the canonical decl, we don't have to
12961 mess with instantiations, and often we can't (for
12962 typename, template type parms and such). Note that
12963 TYPE_NAME is not correct for the above test if
12964 we've copied the type for a typedef. */
12970 }
12972 /* Check to see if we already have the specialization we
12973 need. */
12976 {
12977 /* T is a static data member or namespace-scope entity.
12978 We have to substitute into namespace-scope variables
12979 (not just variable templates) because of cases like:
12981 template <class T> void f() { extern T t; }
12983 where the entity referenced is not known until
12984 instantiation time. */
12988 {
12990 complain,
12992 /* If CTX is unchanged, then T is in fact the
12993 specialization we want. That situation occurs when
12994 referencing a static data member within in its own
12995 class. We can use pointer equality, rather than
12996 same_type_p, because DECL_CONTEXT is always
12997 canonical... */
12999 /* ... unless T is a member template; in which
13000 case our caller can be willing to create a
13001 specialization of that template represented
13002 by T. */
13006 }
13009 {
13014 argvec = (coerce_innermost_template_parms
13022 }
13023 }
13024 else
13025 {
13026 /* A local variable. */
13028 /* Subsequent calls to pushdecl will fill this in. */
13030 /* Unless this is a reference to a static variable from an
13031 enclosing function, in which case we need to fill it in now. */
13033 {
13037 }
13039 }
13040 /* If we already have the specialization we need, there is
13041 nothing more to do. */
13043 {
13046 }
13048 /* Create a new node for the specialization we need. */
13051 {
13054 else
13062 {
13063 /* Mask off any template args past the variable's context so we
13064 don't replace the auto with an unrelated argument. */
13068 /* This should never happen with the new lambda instantiation
13069 model, but keep the handling just in case. */
13072 }
13074 }
13076 {
13077 /* Even if the original location is out of scope, the
13078 newly substituted one is not. */
13085 {
13086 /* It may seem that this case cannot occur, since:
13088 typedef void f();
13089 void g() { f x; }
13091 declares a function, not a variable. However:
13093 typedef void f();
13094 template <typename T> void g() { T t; }
13095 template void g<f>();
13097 is an attempt to declare a variable with function
13098 type. */
13100 /* R is not yet sufficiently initialized, so we
13101 just use its name. */
13104 }
13106 /* Wait until cp_finish_decl to set this again, to handle
13107 circular dependency (template/instantiate6.C). */
13112 {
13117 {
13120 }
13122 }
13126 }
13132 /* Clear out the mangled name and RTL for the instantiation. */
13136 /* The initializer must not be expanded until it is required;
13137 see [temp.inst]. */
13141 {
13147 /* Possibly limit visibility based on template args. */
13150 {
13154 }
13156 }
13159 {
13160 /* A static data member declaration is always marked
13161 external when it is declared in-class, even if an
13162 initializer is present. We mimic the non-template
13163 processing here. */
13171 }
13172 else
13173 {
13178 }
13186 /* Preserve a typedef that names a type. */
13188 {
13192 /* An alias template specialization can be dependent
13193 even if its underlying type is not. */
13195 }
13198 }
13203 }
13204 #undef RETURN
13206 out:
13207 /* Restore the file and line information. */
13211 }
13213 /* Substitute into the ARG_TYPES of a function type.
13214 If END is a TREE_CHAIN, leave it and any following types
13215 un-substituted. */
13217 static tree
13219 tree args,
13220 tree end,
13221 tsubst_flags_t complain,
13222 tree in_decl)
13223 {
13224 tree remaining_arg_types;
13228 tree default_arg;
13239 {
13240 /* For a pack expansion, perform substitution on the
13241 entire expression. Later on, we'll handle the arguments
13242 one-by-one. */
13247 /* So that we'll spin through the parameters, one by one. */
13249 else
13250 {
13251 /* We only partially substituted into the parameter
13252 pack. Our type is TYPE_PACK_EXPANSION. */
13255 }
13256 }
13269 {
13271 {
13275 }
13277 }
13278 /* DR 657. */
13282 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13283 top-level qualifiers as required. */
13286 /* We do not substitute into default arguments here. The standard
13287 mandates that they be instantiated only when needed, which is
13288 done in build_over_call. */
13291 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13292 since the new op() won't have any associated template arguments for us
13293 to refer to later. */
13299 {
13300 /* We've instantiated a template before its default arguments
13301 have been parsed. This can happen for a nested template
13302 class, and is not an error unless we require the default
13303 argument in a call of this function. */
13304 remaining_arg_types =
13307 }
13308 else
13309 remaining_arg_types =
13311 }
13314 }
13316 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13317 *not* handle the exception-specification for FNTYPE, because the
13318 initial substitution of explicitly provided template parameters
13319 during argument deduction forbids substitution into the
13320 exception-specification:
13322 [temp.deduct]
13324 All references in the function type of the function template to the
13325 corresponding template parameters are replaced by the specified tem-
13326 plate argument values. If a substitution in a template parameter or
13327 in the function type of the function template results in an invalid
13328 type, type deduction fails. [Note: The equivalent substitution in
13329 exception specifications is done only when the function is instanti-
13330 ated, at which point a program is ill-formed if the substitution
13331 results in an invalid type.] */
13333 static tree
13335 tree args,
13336 tsubst_flags_t complain,
13337 tree in_decl)
13338 {
13339 tree return_type;
13341 tree fntype;
13343 /* The TYPE_CONTEXT is not used for function/method types. */
13346 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13347 failure. */
13351 {
13352 /* Substitute the argument types. */
13364 {
13365 /* DR 1207: 'this' is in scope in the trailing return type. */
13367 }
13369 /* Substitute the return type. */
13373 {
13376 }
13377 }
13378 else
13379 /* Substitute the return type. */
13384 /* DR 486 clarifies that creation of a function type with an
13385 invalid return type is a deduction failure. */
13388 {
13390 {
13393 else
13395 }
13397 }
13398 /* And DR 657. */
13403 {
13404 /* Substitute the argument types. */
13409 }
13411 /* Construct a new type node and return it. */
13413 {
13418 }
13419 else
13420 {
13422 /* Don't pick up extra function qualifiers from the basetype. */
13425 {
13426 /* [temp.deduct]
13428 Type deduction may fail for any of the following
13429 reasons:
13431 -- Attempting to create "pointer to member of T" when T
13432 is not a class type. */
13435 r);
13437 }
13442 }
13449 }
13451 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13452 ARGS into that specification, and return the substituted
13453 specification. If there is no specification, return NULL_TREE. */
13455 static tree
13457 tree args,
13458 tsubst_flags_t complain,
13459 tree in_decl,
13461 {
13462 tree specs;
13463 tree new_specs;
13468 {
13469 /* A noexcept-specifier. */
13474 {
13475 /* Defer instantiation of noexcept-specifiers to avoid
13476 excessive instantiations (c++/49107). */
13479 {
13480 /* We already partially instantiated this member template,
13481 so combine the new args with the old. */
13486 }
13487 else
13488 {
13491 }
13492 }
13493 else
13494 new_specs = tsubst_copy_and_build
13498 }
13500 {
13503 else
13505 {
13506 tree spec;
13511 {
13512 /* Expand the pack expansion type. */
13515 in_decl);
13521 else
13522 {
13523 /* We're substituting into a member template, so
13524 we got a TYPE_PACK_EXPANSION back. Add that
13525 expansion and move on. */
13529 expanded_specs,
13530 complain);
13533 }
13534 }
13537 {
13540 else
13545 complain);
13546 }
13549 }
13550 }
13552 }
13554 /* Take the tree structure T and replace template parameters used
13555 therein with the argument vector ARGS. IN_DECL is an associated
13556 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13557 Issue error and warning messages under control of COMPLAIN. Note
13558 that we must be relatively non-tolerant of extensions here, in
13559 order to preserve conformance; if we allow substitutions that
13560 should not be allowed, we may allow argument deductions that should
13561 not succeed, and therefore report ambiguous overload situations
13562 where there are none. In theory, we could allow the substitution,
13563 but indicate that it should have failed, and allow our caller to
13564 make sure that the right thing happens, but we don't try to do this
13565 yet.
13567 This function is used for dealing with types, decls and the like;
13568 for expressions, use tsubst_expr or tsubst_copy. */
13570 tree
13572 {
13595 else
13600 /* Reuse typedefs. We need to do this to handle dependent attributes,
13601 such as attribute aligned. */
13604 {
13608 {
13609 /* DECL represents an alias template and we want to
13610 instantiate it. */
13614 }
13618 {
13622 }
13627 else
13628 /* The typedef is from a non-template context. */
13632 {
13634 r = cp_build_qualified_type_real
13638 }
13639 else
13640 {
13641 /* We don't have an instantiation yet, so drop the typedef. */
13646 }
13647 }
13664 {
13690 {
13696 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13697 needed. */
13703 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13704 with TREE_SIDE_EFFECTS that indicates this is not an integral
13705 constant expression. */
13708 {
13711 }
13714 }
13720 {
13726 /* Early in template argument deduction substitution, we don't
13727 want to reduce the level of 'auto', or it will be confused
13728 with a normal template parm in subsequent deduction. */
13740 {
13744 {
13745 /* See through ARGUMENT_PACK_SELECT arguments. */
13747 /* If the selected argument is an expansion E, that most
13748 likely means we were called from
13749 gen_elem_of_pack_expansion_instantiation during the
13750 substituting of pack an argument pack (which Ith
13751 element is a pack expansion, where I is
13752 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13753 In this case, the Ith element resulting from this
13754 substituting is going to be a pack expansion, which
13755 pattern is the pattern of E. Let's return the
13756 pattern of E, and
13757 gen_elem_of_pack_expansion_instantiation will
13758 build the resulting pack expansion from it. */
13760 {
13761 /* Make sure we aren't throwing away arg info. */
13764 }
13765 }
13766 }
13771 {
13773 /* If ARG is an argument pack, we don't actually want to
13774 perform a substitution here, because substitutions
13775 for argument packs are only done
13776 element-by-element. We can get to this point when
13777 substituting the type of a non-type template
13778 parameter pack, when that type actually contains
13779 template parameter packs from an outer template, e.g.,
13781 template<typename... Types> struct A {
13782 template<Types... Values> struct B { };
13783 }; */
13787 {
13793 return cp_build_qualified_type_real
13795 }
13797 {
13798 /* We are processing a type constructed from a
13799 template template parameter. */
13810 /* Consider this code:
13812 template <template <class> class Template>
13813 struct Internal {
13814 template <class Arg> using Bind = Template<Arg>;
13815 };
13817 template <template <class> class Template, class Arg>
13818 using Instantiate = Template<Arg>; //#0
13820 template <template <class> class Template,
13821 class Argument>
13822 using Bind =
13823 Instantiate<Internal<Template>::template Bind,
13824 Argument>; //#1
13826 When #1 is parsed, the
13827 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13828 parameter `Template' in #0 matches the
13829 UNBOUND_CLASS_TEMPLATE representing the argument
13830 `Internal<Template>::template Bind'; We then want
13831 to assemble the type `Bind<Argument>' that can't
13832 be fully created right now, because
13833 `Internal<Template>' not being complete, the Bind
13834 template cannot be looked up in that context. So
13835 we need to "store" `Bind<Argument>' for later
13836 when the context of Bind becomes complete. Let's
13837 store that in a TYPENAME_TYPE. */
13841 argvec),
13842 typename_type,
13843 complain);
13845 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13846 are resolving nested-types in the signature of a
13847 member function templates. Otherwise ARG is a
13848 TEMPLATE_DECL and is the real template to be
13849 instantiated. */
13857 complain);
13858 return cp_build_qualified_type_real
13860 }
13863 else
13864 /* TEMPLATE_PARM_INDEX. */
13866 }
13869 /* This can happen during the attempted tsubst'ing in
13870 unify. This means that we don't yet have any information
13871 about the template parameter in question. */
13874 /* If we get here, we must have been looking at a parm for a
13875 more deeply nested template. Make a new version of this
13876 template parameter, but with a lower level. */
13878 {
13883 {
13885 r = cp_build_qualified_type_real
13889 }
13896 /* Break infinite recursion when substituting the constraints
13898 else
13899 {
13910 {
13911 /* Propagate constraints on placeholders. */
13916 {
13920 }
13921 }
13924 /* We have reduced the level of the template
13925 template parameter, but not the levels of its
13926 template parameters, so canonical_type_parameter
13927 will not be able to find the canonical template
13928 template parameter for this level. Thus, we
13929 require structural equality checking to compare
13930 TEMPLATE_TEMPLATE_PARMs. */
13934 else
13938 {
13940 /* We might need to substitute into the types of non-type
13941 template parameters. */
13953 }
13954 }
13958 /* OK, now substitute the type of the non-type parameter. We
13959 couldn't do it earlier because it might be an auto parameter,
13960 and we wouldn't need to if we had an argument. */
13969 }
13972 }
13975 {
13983 {
13987 }
13990 {
13994 }
13997 {
14001 }
14007 }
14010 /* We should never be tsubsting a binfo. */
14014 /* A vector of template arguments. */
14020 {
14024 /* [temp.deduct]
14026 Type deduction may fail for any of the following
14027 reasons:
14029 -- Attempting to create a pointer to reference type.
14030 -- Attempting to create a reference to a reference type or
14031 a reference to void.
14033 Core issue 106 says that creating a reference to a reference
14034 during instantiation is no longer a cause for failure. We
14035 only enforce this check in strict C++98 mode. */
14039 {
14042 /* We keep track of the last time we issued this error
14043 message to avoid spewing a ton of messages during a
14044 single bad template instantiation. */
14047 {
14052 else
14055 }
14058 }
14062 {
14064 {
14067 type);
14068 else
14070 type);
14071 }
14073 }
14075 {
14079 }
14081 /* In C++0x, during template argument substitution, when there is an
14082 attempt to create a reference to a reference type, reference
14083 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14085 "If a template-argument for a template-parameter T names a type
14086 that is a reference to a type A, an attempt to create the type
14087 'lvalue reference to cv T' creates the type 'lvalue reference to
14088 A,' while an attempt to create the type type rvalue reference to
14089 cv T' creates the type T"
14090 */
14091 r = cp_build_reference_type
14094 else
14099 /* Will this ever be needed for TYPE_..._TO values? */
14103 }
14105 {
14108 {
14109 /* [temp.deduct]
14111 Type deduction may fail for any of the following
14112 reasons:
14114 -- Attempting to create "pointer to member of T" when T
14115 is not a class type. */
14119 }
14121 {
14125 }
14127 {
14131 }
14134 {
14135 /* The type of the implicit object parameter gets its
14136 cv-qualifiers from the FUNCTION_TYPE. */
14137 tree memptr;
14138 tree method_type
14143 complain);
14144 }
14145 else
14148 complain);
14149 }
14152 {
14153 tree fntype;
14154 tree specs;
14159 /* Substitute the exception specification. */
14167 }
14169 {
14174 /* As an optimization, we avoid regenerating the array type if
14175 it will obviously be the same as T. */
14179 /* These checks should match the ones in create_array_type_for_decl.
14181 [temp.deduct]
14183 The deduction may fail for any of the following reasons:
14185 -- Attempting to create an array with an element type that
14186 is void, a function type, or a reference type, or [DR337]
14187 an abstract class type. */
14193 {
14197 }
14205 {
14208 }
14211 }
14214 {
14226 {
14230 }
14232 {
14233 /* Normally, make_typename_type does not require that the CTX
14234 have complete type in order to allow things like:
14236 template <class T> struct S { typename S<T>::X Y; };
14238 But, such constructs have already been resolved by this
14239 point, so here CTX really should have complete type, unless
14240 it's a partial instantiation. */
14243 {
14247 }
14248 }
14255 {
14258 }
14261 {
14263 {
14267 else
14269 }
14271 {
14275 else
14277 }
14278 }
14280 return cp_build_qualified_type_real
14282 }
14285 {
14297 }
14300 {
14301 tree type;
14317 complain);
14318 }
14321 {
14322 tree type;
14333 {
14335 {
14339 }
14342 }
14353 else
14354 {
14358 /* In a template ~id could be either a complement expression
14359 or an unqualified-id naming a destructor; if instantiating
14360 it produces an expression, it's not an id-expression or
14361 member access. */
14364 }
14369 }
14372 {
14376 }
14380 {
14381 tree r;
14385 else
14393 }
14408 /* We should use one of the expression tsubsts for these codes. */
14414 }
14415 }
14417 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14418 expression on the left-hand side of the "." or "->" operator. We
14419 only do the lookup if we had a dependent BASELINK. Otherwise we
14420 adjust it onto the instantiated heirarchy. */
14422 static tree
14425 {
14437 {
14444 }
14451 {
14457 /* Treat as-if non-dependent below. */
14462 {
14468 }
14472 }
14473 else
14474 /* We're going to overwrite pieces below, make a duplicate. */
14477 /* If lookup found a single function, mark it as used at this point.
14478 (If lookup found multiple functions the one selected later by
14479 overload resolution will be marked as used at that point.) */
14485 {
14486 /* Add back the template arguments, if present. */
14491 /* Update the conversion operator type. */
14493 }
14499 {
14501 qualifying_scope,
14502 object_type);
14504 /* We need to call adjust_result_of_qualified_name_lookup in case the
14505 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14506 so that we still get virtual function binding. */
14508 }
14511 }
14513 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14514 true if the qualified-id will be a postfix-expression in-and-of
14515 itself; false if more of the postfix-expression follows the
14516 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14517 of "&". */
14519 static tree
14523 {
14524 tree expr;
14525 tree scope;
14526 tree name;
14528 tree template_args;
14533 /* Figure out what name to look up. */
14536 {
14546 }
14547 else
14548 {
14551 }
14553 /* Substitute into the qualifying scope. When there are no ARGS, we
14554 are just trying to simplify a non-dependent expression. In that
14555 case the qualifying scope may be dependent, and, in any case,
14556 substituting will not help. */
14559 {
14562 }
14563 else
14567 {
14574 }
14577 {
14579 {
14580 /* A BIT_NOT_EXPR is used to represent a destructor. */
14582 {
14586 }
14587 else
14590 }
14591 else
14595 {
14597 {
14601 }
14603 }
14604 }
14607 {
14609 scope);
14610 /* Remember that there was a reference to this entity. */
14613 }
14616 {
14622 }
14625 {
14628 complain);
14629 else
14631 }
14637 {
14638 expr = (adjust_result_of_qualified_name_lookup
14640 expr = (finish_qualified_id_expr
14644 }
14646 /* Expressions do not generally have reference type. */
14648 /* However, if we're about to form a pointer-to-member, we just
14649 want the referenced member referenced. */
14657 }
14659 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14660 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14661 for tsubst. */
14663 static tree
14666 {
14673 {
14674 /* If we had an initializer but it
14675 instantiated to nothing,
14676 value-initialize the object. This will
14677 only occur when the initializer was a
14678 pack expansion where the parameter packs
14679 used in that expansion were of length
14680 zero. */
14682 complain);
14687 }
14690 }
14692 /* Like tsubst, but deals with expressions. This function just replaces
14693 template parms; to finish processing the resultant expression, use
14694 tsubst_copy_and_build or tsubst_expr. */
14696 static tree
14698 {
14700 tree r;
14708 {
14713 {
14714 /* We get here for a use of 'this' in an NSDMI. */
14718 /* This can happen for a parameter name used later in a function
14719 declaration (such as in a late-specified return type). Just
14720 make a dummy decl, since it's only used for its type. */
14723 /* Give it the template pattern as its context; its true context
14724 hasn't been instantiated yet and this is good enough for
14725 mangling. */
14727 }
14736 {
14737 tree enum_type;
14738 tree v;
14742 /* There is no need to substitute into namespace-scope
14743 enumerators. */
14746 /* If ARGS is NULL, then T is known to be non-dependent. */
14750 /* Unfortunately, we cannot just call lookup_name here.
14751 Consider:
14753 template <int I> int f() {
14754 enum E { a = I };
14755 struct S { void g() { E e = a; } };
14756 };
14758 When we instantiate f<7>::S::g(), say, lookup_name is not
14759 clever enough to find f<7>::a. */
14760 enum_type
14770 /* We didn't find the name. That should never happen; if
14771 name-lookup found it during preliminary parsing, we
14772 should find it again here during instantiation. */
14774 }
14779 {
14780 /* Check for a local specialization set up by
14781 tsubst_pack_expansion. */
14783 {
14787 }
14789 /* When retrieving a capture pack from a generic lambda, remove the
14790 lambda call op's own template argument list from ARGS. Only the
14791 template arguments active for the closure type should be used to
14792 retrieve the pack specialization. */
14798 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14799 tsubst_decl put in the hash table. */
14801 }
14804 {
14805 tree ctx;
14810 {
14813 {
14817 }
14819 }
14820 }
14830 {
14833 {
14834 /* First try name lookup to find the instantiation. */
14837 {
14838 /* Make sure that the one we found is the one we want. */
14842 }
14846 else
14847 {
14848 /* This can happen for a variable used in a
14849 late-specified return type of a local lambda, or for a
14850 local static or constant. Building a new VAR_DECL
14851 should be OK in all those cases. */
14854 /* Avoid infinite recursion (79640). */
14857 {
14858 /* We can't call cp_finish_decl, so handle the
14859 initializer by hand. */
14874 }
14881 }
14882 /* Remember this for subsequent uses. */
14885 }
14886 }
14887 else
14897 /* An OVERLOAD will always be a non-dependent overload set; an
14898 overload set from function scope will just be represented with an
14899 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14901 /* We must have marked any lookups as persistent. */
14917 {
14918 /* Template template argument like the following example need
14919 special treatment:
14921 template <template <class> class TT> struct C {};
14922 template <class T> struct D {
14923 template <class U> struct E {};
14924 C<E> c; // #1
14925 };
14926 D<int> d; // #2
14928 We are processing the template argument `E' in #1 for
14929 the template instantiation #2. Originally, `E' is a
14930 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14931 have to substitute this with one having context `D<int>'. */
14935 {
14936 /* When rewriting a constructor into a deduction guide, a
14937 non-dependent name can become dependent, so memtmpl<args>
14938 becomes context::template memtmpl<args>. */
14942 }
14944 }
14945 else
14946 /* Ordinary template template argument. */
14951 {
14952 /* Handle location wrappers by substituting the wrapped node
14953 first, *then* reusing the resulting type. Doing the type
14954 first ensures that we handle template parameters and
14955 parameter pack expansions. */
14959 }
14969 {
14973 }
14978 {
14987 /* We only want to compute the number of arguments. */
14990 else
14997 {
14999 /* Set TREE_USED for the benefit of -Wunused. */
15003 }
15011 {
15016 else
15022 else
15025 }
15026 else
15028 }
15030 {
15038 }
15039 /* Fall through */
15055 {
15059 }
15062 {
15063 tree object;
15064 tree name;
15069 {
15073 }
15076 {
15086 }
15091 in_decl);
15092 else
15095 }
15133 {
15137 }
15140 {
15145 }
15148 {
15152 }
15155 {
15163 }
15169 {
15176 }
15179 {
15186 }
15189 {
15196 }
15199 {
15200 /* Substituted template arguments */
15209 }
15212 {
15232 }
15257 /* Fall through. */
15260 {
15263 }
15264 else
15268 /* This is handled by tsubst_copy_and_build. */
15272 {
15276 }
15279 /* We shouldn't have built any of these during initial template
15280 generation. Instead, they should be built during instantiation
15281 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15285 {
15295 }
15313 {
15314 /* Instantiate any typedefs in the type. */
15319 }
15322 /* These can sometimes show up in a partial instantiation, but never
15323 involve template parms. */
15339 /* ??? There's no point in copying it for now, but maybe some
15340 day it will contain more information, such as a pointer back
15341 to the containing function, inlined copy or so. */
15345 /* We shouldn't get here, but keep going if !flag_checking. */
15349 }
15350 }
15352 /* Helper function for tsubst_omp_clauses, used for instantiation of
15353 OMP_CLAUSE_DECL of clauses. */
15355 static tree
15357 tree in_decl)
15358 {
15362 /* Handle an OpenMP array section represented as a TREE_LIST (or
15363 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15364 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15365 TREE_LIST. We can handle it exactly the same as an array section
15366 (purpose, value, and a chain), even though the nomenclature
15367 (low_bound, length, etc) is different. */
15369 {
15370 tree low_bound
15376 in_decl);
15385 }
15388 /* Undo convert_from_reference tsubst_expr could have called. */
15394 }
15396 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15398 static tree
15401 {
15406 {
15412 {
15415 {
15421 }
15422 /* FALLTHRU */
15437 in_decl);
15469 {
15472 {
15479 }
15480 else
15482 }
15485 in_decl);
15491 in_decl);
15499 in_decl);
15501 {
15504 }
15509 else
15512 in_decl,
15536 }
15539 {
15549 /* tsubst_expr on SCOPE_REF results in returning
15550 finish_non_static_data_member result. Undo that here. */
15554 {
15559 {
15563 CASE_CONVERT:
15572 /* FALLTHRU */
15576 }
15577 }
15583 {
15586 {
15589 }
15590 }
15594 }
15595 }
15599 {
15604 {
15607 }
15608 }
15610 }
15612 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15614 static tree
15616 tree in_decl)
15617 {
15618 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15638 {
15641 else
15642 {
15646 }
15647 }
15652 #undef RECUR
15653 }
15655 /* Used to temporarily communicate the list of #pragma omp parallel
15656 clauses to #pragma omp for instantiation if they are combined
15657 together. */
15661 /* Substitute one OMP_FOR iterator. */
15663 static void
15668 {
15669 #define RECUR(NODE) \
15670 tsubst_expr ((NODE), args, complain, in_decl, \
15671 integral_constant_expression_p)
15678 {
15681 }
15687 {
15688 /* We need to jump through some hoops to handle declarations in the
15689 init-statement, since we might need to handle auto deduction,
15690 but we need to keep control of initialization. */
15694 }
15695 else
15696 {
15698 {
15701 {
15705 {
15709 CASE_CONVERT:
15717 {
15720 }
15721 /* FALLTHRU */
15725 }
15726 }
15727 }
15728 else
15730 }
15741 {
15743 {
15744 /* Declare the variable, but don't let that initialize it. */
15749 }
15754 {
15759 }
15760 else
15767 }
15770 {
15771 /* Declare and initialize the variable. */
15774 }
15776 {
15780 {
15782 {
15788 {
15791 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15796 }
15799 {
15801 decl);
15803 }
15806 {
15808 decl);
15810 }
15811 else
15813 }
15816 }
15818 {
15823 {
15826 }
15827 }
15828 }
15831 {
15835 }
15836 else
15840 {
15851 {
15859 }
15860 else
15866 {
15872 }
15876 {
15884 }
15885 else
15891 }
15897 #undef RECUR
15898 }
15900 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15901 of OMP_TARGET's body. */
15903 static tree
15905 {
15908 {
15917 }
15919 }
15921 /* Helper function for tsubst_expr. For decomposition declaration
15922 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15923 also the corresponding decls representing the identifiers
15924 of the decomposition declaration. Return DECL if successful
15925 or error_mark_node otherwise, set *FIRST to the first decl
15926 in the list chained through DECL_CHAIN and *CNT to the number
15927 of such decls. */
15929 static tree
15933 {
15938 decl2
15943 {
15945 {
15948 }
15965 {
15968 }
15969 else
15971 }
15974 }
15976 /* Like tsubst_copy for expressions, etc. but also does semantic
15977 processing. */
15979 tree
15982 {
15983 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15984 #define RECUR(NODE) \
15985 tsubst_expr ((NODE), args, complain, in_decl, \
15986 integral_constant_expression_p)
15989 tree r;
15990 location_t loc;
16002 {
16004 {
16005 tree_stmt_iterator i;
16009 }
16024 else
16034 {
16036 tree init;
16042 {
16052 else
16054 }
16056 {
16057 /* Don't build up decls for a variadic capture proxy, we'll
16058 instantiate the elements directly as needed. */
16060 }
16063 {
16064 /* We're in tsubst_lambda_expr, we've already inserted a new
16065 capture proxy, so look it up and register it. */
16071 }
16074 /* Don't copy the old closure; we'll create a new one in
16075 tsubst_lambda_expr. */
16077 else
16078 {
16082 {
16083 /* By marking the declaration as instantiated, we avoid
16084 trying to instantiate it. Since instantiate_decl can't
16085 handle local variables, and since we've already done
16086 all that needs to be done, that's the right thing to
16087 do. */
16092 /* Anonymous aggregates are a special case. */
16095 {
16098 {
16102 }
16104 }
16110 {
16115 }
16116 else
16117 {
16122 {
16123 /* For __PRETTY_FUNCTION__ we have to adjust the
16124 initializer. */
16128 }
16129 else
16133 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16138 {
16140 tree first;
16141 tree ndecl
16149 }
16150 else
16152 }
16153 }
16154 }
16157 }
16167 {
16171 }
16176 {
16177 /* Construct another range_for, if this is not a final
16178 substitution (for inside inside a generic lambda of a
16179 template). Otherwise convert to a regular for. */
16181 stmt = (processing_template_decl
16197 {
16201 }
16202 else
16203 {
16209 }
16215 }
16222 {
16226 }
16232 {
16236 }
16249 else
16250 {
16257 }
16263 {
16272 }
16280 else
16288 else
16309 {
16316 }
16320 {
16322 tree label;
16329 }
16335 /* Computed goto's must be tsubst'd into. On the other hand,
16336 non-computed gotos must not be; the identifier in question
16337 will have no binding. */
16339 else
16345 {
16361 }
16366 {
16371 }
16372 else
16373 {
16378 else
16385 else
16391 else
16393 }
16397 {
16401 {
16403 /* Prevent instantiate_decl from trying to instantiate
16404 this variable. We've already done all that needs to be
16405 done. */
16408 }
16413 }
16419 {
16420 /* Local classes are not independent templates; they are
16421 instantiated along with their containing function. And this
16422 way we don't have to deal with pushing out of one local class
16423 to instantiate a member of another local class. */
16424 /* Closures are handled by the LAMBDA_EXPR. */
16434 }
16438 {
16439 tree condition;
16442 condition =
16444 args,
16453 }
16459 in_decl);
16494 {
16507 in_decl);
16509 {
16516 }
16528 integral_constant_expression_p);
16539 else
16540 {
16548 }
16552 }
16557 /* FALLTHRU */
16564 in_decl);
16581 in_decl);
16592 {
16595 {
16596 /* For combined target teams, ensure the num_teams and
16597 thread_limit clause expressions are evaluated on the host,
16598 before entering the target construct. */
16599 tree c;
16605 {
16614 OMP_CLAUSE_FIRSTPRIVATE);
16618 }
16619 }
16620 }
16680 {
16685 {
16688 }
16694 }
16695 else
16696 {
16703 {
16706 }
16709 {
16714 {
16717 }
16723 }
16724 else
16725 {
16729 }
16732 }
16736 {
16742 {
16746 {
16751 }
16755 }
16756 else
16757 {
16762 }
16763 }
16767 {
16771 }
16784 /* If the first operand was a statement, we're done with it. */
16788 complain));
16802 integral_constant_expression_p));
16803 }
16806 out:
16809 #undef RECUR
16810 #undef RETURN
16811 }
16813 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16814 function. For description of the body see comment above
16815 cp_parser_omp_declare_reduction_exprs. */
16817 static void
16819 {
16825 tree_stmt_iterator tsi;
16836 {
16855 }
16857 {
16877 }
16878 }
16880 /* T is a postfix-expression that is not being used in a function
16881 call. Return the substituted version of T. */
16883 static tree
16885 tsubst_flags_t complain,
16886 tree in_decl)
16887 {
16891 else
16897 }
16899 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16900 instantiation context. Instantiating a pack expansion containing a lambda
16901 might result in multiple lambdas all based on the same lambda in the
16902 template. */
16904 tree
16906 {
16920 else
16928 {
16940 else
16945 {
16954 }
16955 else
16956 {
16962 }
16963 }
16967 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16985 else
16986 {
16987 /* Fix the type of 'this'. */
16993 {
16997 }
16998 else
16999 {
17003 }
17005 /* Let finish_function set this. */
17026 /* The capture list was built up in reverse order; fix that now. */
17033 }
17040 }
17042 /* Like tsubst but deals with expressions and performs semantic
17043 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17045 tree
17047 tree args,
17048 tsubst_flags_t complain,
17049 tree in_decl,
17052 {
17053 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17054 #define RECUR(NODE) \
17055 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17057 integral_constant_expression_p)
17060 location_t loc;
17069 /* N3276 decltype magic only applies to calls at the top level or on the
17070 right side of a comma. */
17075 {
17078 /* Fall through. */
17080 {
17081 tree decl;
17082 cp_id_kind idk;
17087 {
17090 }
17092 /* Look up the name. */
17095 /* By convention, expressions use ERROR_MARK_NODE to indicate
17096 failure, not NULL_TREE. */
17102 integral_constant_expression_p,
17110 input_location);
17114 {
17118 }
17120 }
17123 {
17124 tree object;
17134 {
17139 }
17145 {
17148 }
17149 else
17156 else
17158 }
17161 {
17165 {
17166 /* A type conversion to reference type will be enclosed in
17167 such an indirect ref, but the substitution of the cast
17168 will have also added such an indirect ref. */
17170 }
17171 else
17179 }
17182 {
17186 }
17189 {
17193 {
17198 }
17200 /* We'll pass this to convert_nontype_argument again, we don't need
17201 to actually perform any conversion here. */
17207 flags));
17208 }
17211 {
17215 }
17222 {
17223 tree type;
17229 {
17234 }
17241 {
17259 }
17262 }
17296 else
17298 in_decl);
17333 {
17340 tree r = build_x_binary_op
17342 op0,
17344 ? ERROR_MARK
17346 op1,
17348 ? ERROR_MARK
17356 }
17359 {
17363 }
17379 /* Fall through */
17382 {
17383 tree r;
17389 {
17390 /* When there are no ARGS, we are trying to evaluate a
17391 non-dependent expression from the parser. Trying to do
17392 the substitutions may not work. */
17395 }
17396 else
17397 {
17402 else
17405 /*integral_constant_expression_p=*/
17409 }
17413 else
17417 {
17419 {
17421 {
17425 }
17426 else
17430 }
17432 }
17434 }
17437 {
17447 }
17463 {
17467 tree r = build_x_modify_expr
17470 /* TREE_NO_WARNING must be set if either the expression was
17471 parenthesized or it uses an operator such as >>= rather
17472 than plain assignment. In the former case, it was already
17473 set and must be copied. In the latter case,
17474 build_x_modify_expr sets it and it must not be reset
17475 here. */
17480 }
17485 /* Remember that there was a reference to this entity. */
17492 {
17497 tree ret;
17501 else
17502 {
17506 }
17508 /* If there was an initializer in the original tree, but it
17509 instantiated to an empty list, then we should pass a
17510 non-NULL empty vector to tell build_new that it was an
17511 empty initializer() rather than no initializer. This can
17512 only happen when the initializer is a pack expansion whose
17513 parameter packs are of length zero. */
17516 else
17517 {
17521 else
17522 {
17525 }
17526 }
17532 complain);
17540 }
17543 {
17549 complain));
17550 }
17553 {
17557 integral_constant_expression_p);
17559 op0,
17562 }
17565 {
17566 tree function;
17571 tree ret;
17574 /* Internal function with no arguments. */
17578 /* When we parsed the expression, we determined whether or
17579 not Koenig lookup should be performed. */
17582 {
17585 }
17587 {
17592 }
17594 {
17595 /* Do nothing; calling tsubst_copy_and_build on an identifier
17596 would incorrectly perform unqualified lookup again.
17598 Note that we can also have an IDENTIFIER_NODE if the earlier
17599 unqualified lookup found a member function; in that case
17600 koenig_p will be false and we do want to do the lookup
17601 again to find the instantiated member function.
17603 FIXME but doing that causes c++/15272, so we need to stop
17604 using IDENTIFIER_NODE in that situation. */
17606 }
17607 else
17608 {
17610 {
17616 }
17617 else
17622 /* Avoid error about taking the address of a constructor. */
17626 in_decl,
17628 integral_constant_expression_p);
17632 }
17637 {
17642 else
17643 {
17644 /* Expand the pack expansion and push each entry onto
17645 CALL_ARGS. */
17648 {
17653 {
17658 }
17659 }
17660 else
17661 {
17662 /* A partial substitution. Add one entry. */
17664 }
17665 }
17666 }
17668 /* We do not perform argument-dependent lookup if normal
17669 lookup finds a non-function, in accordance with the
17670 expected resolution of DR 218. */
17673 /* If lookup found a member function, the Koenig lookup is
17674 not appropriate, even if an unqualified-name was used
17675 to denote the function. */
17678 /* Only do this when substitution turns a dependent call
17679 into a non-dependent call. */
17687 {
17689 {
17690 /* For backwards compatibility and good diagnostics, try
17691 the unqualified lookup again if we aren't in SFINAE
17692 context. */
17693 tree unq = (tsubst_copy_and_build
17695 integral_constant_expression_p));
17697 {
17700 }
17703 {
17704 /* In a lambda fn, we have to be careful to not
17705 introduce new this captures. Legacy code can't
17706 be using lambdas anyway, so it's ok to be
17707 stricter. */
17712 "and no declarations were found by "
17713 "argument-dependent lookup at the point "
17720 else
17724 {
17735 {
17737 input_location);
17739 "declarations in dependent base %qT are "
17745 else
17749 }
17750 else
17752 "%qD declared here, later in the "
17755 {
17758 }
17759 }
17762 }
17763 }
17765 {
17770 }
17771 }
17773 /* Remember that there was a reference to this entity. */
17777 {
17780 }
17782 /* Put back tf_decltype for the actual call. */
17787 {
17791 {
17793 "wrong number of arguments to "
17796 }
17797 else
17799 input_location),
17804 /* Unsupported internal function with arguments. */
17806 }
17809 complain);
17811 {
17826 complain);
17827 else
17828 ret = (build_new_method_call
17833 complain));
17834 }
17835 else
17838 koenig_p,
17839 complain);
17844 {
17850 {
17856 {
17859 else
17861 /* The thunk location is not interesting. */
17863 }
17864 }
17865 }
17868 }
17871 {
17877 {
17879 {
17884 }
17885 else
17886 {
17891 }
17893 }
17894 else
17895 {
17898 }
17903 }
17906 {
17911 input_location));
17912 }
17915 {
17923 {
17924 /* We have pack expansions, so expand those and
17925 create a new list out of it. */
17928 tree chain;
17931 /* Expand the argument expressions. */
17939 /* Build the rest of the list. */
17944 /* Determine the number of arguments. */
17946 {
17949 }
17952 else
17953 {
17954 /* Since we only performed a partial substitution into
17955 the argument pack, we only RETURN (a single list
17956 node. */
17963 }
17965 /* Convert the argument vectors into a TREE_LIST */
17968 {
17969 /* Grab the Ith values. */
17970 i--;
17973 value
17977 /* Build the list (backwards). */
17979 }
17982 }
17998 }
18001 {
18002 tree object;
18003 tree object_type;
18004 tree member;
18005 tree r;
18009 /* Remember that there was a reference to this entity. */
18020 else
18026 {
18031 }
18035 {
18037 {
18042 {
18045 }
18047 {
18052 }
18053 }
18054 }
18057 {
18058 /* Lookup the template functions now that we know what the
18059 scope is. */
18067 {
18070 args);
18071 member = (adjust_result_of_qualified_name_lookup
18073 object_type));
18074 }
18075 else
18076 {
18078 input_location);
18080 }
18081 }
18085 {
18087 {
18091 else
18094 }
18096 }
18100 complain);
18104 }
18111 {
18119 tree r;
18124 /* We do not want to process the index of aggregate
18125 initializers as they are identifier nodes which will be
18126 looked up by digest_init. */
18132 {
18134 /* An identifier index is looked up in the type
18135 being initialized, not the current scope. */
18140 {
18141 /* Substitute into the pack expansion. */
18143 in_decl);
18147 ;
18149 /* Just move the argument into place. */
18151 else
18152 {
18153 /* Update the length of the final CONSTRUCTOR
18154 arguments vector, and note that we will need to
18155 copy.*/
18158 }
18159 }
18160 else
18162 }
18165 {
18170 {
18172 {
18177 }
18178 else
18180 }
18181 }
18187 {
18192 }
18196 }
18199 {
18202 {
18205 }
18206 else
18207 {
18210 }
18211 }
18217 {
18218 /* We don't build decls for an instantiation of a
18219 variadic capture proxy, we instantiate the elements
18220 when needed. */
18223 }
18224 /* Fall through */
18227 {
18229 /* ??? We're doing a subset of finish_id_expression here. */
18231 && !processing_template_decl
18232 && !cp_unevaluated_operand
18235 {
18237 /* Replace an evaluated use of the thread_local variable with
18238 a call to its wrapper. */
18240 }
18245 /* If the original type was a reference, we'll be wrapped in
18246 the appropriate INDIRECT_REF. */
18249 }
18252 {
18256 }
18259 {
18260 tree object_ptr
18267 }
18274 {
18285 }
18288 {
18294 integral_constant_expression_p);
18298 /* If the resulting list of expression statement is empty,
18299 fold it further into void_node. */
18304 }
18307 {
18311 }
18314 /* We can get here for a constant initializer of non-dependent type.
18315 FIXME stop folding in cp_parser_initializer_clause. */
18316 {
18318 complain);
18320 }
18324 integral_constant_expression_p));
18330 {
18335 complain));
18336 }
18343 /* We should only see these for location wrapper nodes, or within
18344 instantiate_non_dependent_expr (when args is NULL_TREE). */
18349 /* fallthrough. */
18352 /* Handle Objective-C++ constructs, if appropriate. */
18353 {
18354 tree subst
18359 }
18361 }
18363 #undef RECUR
18364 #undef RETURN
18365 out:
18368 }
18370 /* Verify that the instantiated ARGS are valid. For type arguments,
18371 make sure that the type's linkage is ok. For non-type arguments,
18372 make sure they are constants if they are integral or enumerations.
18373 Emit an error under control of COMPLAIN, and return TRUE on error. */
18375 static bool
18377 {
18381 {
18391 }
18393 {
18394 /* [basic.link]: A name with no linkage (notably, the name
18395 of a class or enumeration declared in a local scope)
18396 shall not be used to declare an entity with linkage.
18397 This implies that names with no linkage cannot be used as
18398 template arguments
18400 DR 757 relaxes this restriction for C++0x. */
18405 {
18406 /* DR 488 makes use of a type with no linkage cause
18407 type deduction to fail. */
18409 {
18412 else
18415 }
18417 }
18418 /* In order to avoid all sorts of complications, we do not
18419 allow variably-modified types as template arguments. */
18421 {
18425 }
18426 }
18427 /* Class template and alias template arguments should be OK. */
18429 ;
18430 /* A non-type argument of integral or enumerated type must be a
18431 constant. */
18436 {
18440 }
18442 }
18444 static bool
18446 {
18451 {
18454 }
18458 }
18460 /* We're out of SFINAE context now, so generate diagnostics for the access
18461 errors we saw earlier when instantiating D from TMPL and ARGS. */
18463 static void
18465 {
18477 }
18479 /* Instantiate the indicated variable, function, or alias template TMPL with
18480 the template arguments in TARG_PTR. */
18482 static tree
18484 {
18486 tree fndecl;
18487 tree gen_tmpl;
18488 tree spec;
18496 /* If this function is a clone, handle it specially. */
18498 {
18499 tree spec;
18500 tree clone;
18502 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18503 DECL_CLONED_FUNCTION. */
18509 /* Look for the clone. */
18513 /* We should always have found the clone by now. */
18516 }
18521 /* Check to see if we already have this specialization. */
18525 /* targ_ptr only has the innermost template args, so add the outer ones
18526 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18527 the case of a non-dependent call within a template definition). */
18528 targ_ptr = (add_outermost_template_args
18530 targ_ptr));
18532 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18533 but it doesn't seem to be on the hot path. */
18542 {
18544 {
18548 }
18550 }
18553 complain))
18556 /* We are building a FUNCTION_DECL, during which the access of its
18557 parameters and return types have to be checked. However this
18558 FUNCTION_DECL which is the desired context for access checking
18559 is not built yet. We solve this chicken-and-egg problem by
18560 deferring all checks until we have the FUNCTION_DECL. */
18563 /* Instantiation of the function happens in the context of the function
18564 template, not the context of the overload resolution we're doing. */
18566 /* If there are dependent arguments, e.g. because we're doing partial
18567 ordering, make sure processing_template_decl stays set. */
18571 {
18575 }
18581 {
18582 /* We need to determine if we're using a partial or explicit
18583 specialization now, because the type of the variable could be
18584 different. */
18590 {
18595 }
18596 }
18598 /* Substitute template parameters to obtain the specialization. */
18606 {
18609 }
18611 /* The DECL_TI_TEMPLATE should always be the immediate parent
18612 template, not the most general template. */
18616 /* Now we know the specialization, compute access previously
18617 deferred. Do no access control for inheriting constructors,
18618 as we already checked access for the inherited constructor. */
18621 {
18626 }
18629 /* If we've just instantiated the main entry point for a function,
18630 instantiate all the alternate entry points as well. We do this
18631 by cloning the instantiation of the main entry point, not by
18632 instantiating the template clones. */
18637 {
18639 {
18640 /* Remember to reinstantiate when we're out of SFINAE so the user
18641 can see the errors. */
18643 }
18645 }
18647 }
18649 /* Wrapper for instantiate_template_1. */
18651 tree
18653 {
18654 tree ret;
18659 }
18661 /* Instantiate the alias template TMPL with ARGS. Also push a template
18662 instantiation level, which instantiate_template doesn't do because
18663 functions and variables have sufficient context established by the
18664 callers. */
18666 static tree
18668 {
18675 {
18678 }
18680 args =
18688 /* We can't free this if a pending_template entry or last_error_tinst_level
18689 is pointing at it. */
18695 }
18697 /* PARM is a template parameter pack for FN. Returns true iff
18698 PARM is used in a deducible way in the argument list of FN. */
18700 static bool
18702 {
18705 {
18707 tree packs;
18713 {
18714 /* The template parameter pack is used in a function parameter
18715 pack. If this is the end of the parameter list, the
18716 template parameter pack is deducible. */
18719 else
18720 /* Otherwise, not. Well, it could be deduced from
18721 a non-pack parameter, but doing so would end up with
18722 a deduction mismatch, so don't bother. */
18724 }
18725 }
18726 /* The template parameter pack isn't used in any function parameter
18727 packs, but it might be used deeper, e.g. tuple<Args...>. */
18729 }
18731 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18732 NARGS elements of the arguments that are being used when calling
18733 it. TARGS is a vector into which the deduced template arguments
18734 are placed.
18736 Returns either a FUNCTION_DECL for the matching specialization of FN or
18737 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18738 true, diagnostics will be printed to explain why it failed.
18740 If FN is a conversion operator, or we are trying to produce a specific
18741 specialization, RETURN_TYPE is the return type desired.
18743 The EXPLICIT_TARGS are explicit template arguments provided via a
18744 template-id.
18746 The parameter STRICT is one of:
18748 DEDUCE_CALL:
18749 We are deducing arguments for a function call, as in
18750 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18751 deducing arguments for a call to the result of a conversion
18752 function template, as in [over.call.object].
18754 DEDUCE_CONV:
18755 We are deducing arguments for a conversion function, as in
18756 [temp.deduct.conv].
18758 DEDUCE_EXACT:
18759 We are deducing arguments when doing an explicit instantiation
18760 as in [temp.explicit], when determining an explicit specialization
18761 as in [temp.expl.spec], or when taking the address of a function
18762 template, as in [temp.deduct.funcaddr]. */
18764 tree
18766 tree explicit_targs,
18767 tree targs,
18770 tree return_type,
18771 unification_kind_t strict,
18775 {
18776 tree parms;
18777 tree fntype;
18790 tree tinst;
18796 full_targs = (add_outermost_template_args
18798 targs));
18803 /* In C++0x, it's possible to have a function template whose type depends
18804 on itself recursively. This is most obvious with decltype, but can also
18805 occur with enumeration scope (c++/48969). So we need to catch infinite
18806 recursion and reject the substitution at deduction time; this function
18807 will return error_mark_node for any repeated substitution.
18809 This also catches excessive recursion such as when f<N> depends on
18810 f<N-1> across all integers, and returns error_mark_node for all the
18811 substitutions back up to the initial one.
18813 This is, of course, not reentrant. */
18823 {
18824 /* [temp.deduct]
18826 The specified template arguments must match the template
18827 parameters in kind (i.e., type, nontype, template), and there
18828 must not be more arguments than there are parameters;
18829 otherwise type deduction fails.
18831 Nontype arguments must match the types of the corresponding
18832 nontype template parameters, or must be convertible to the
18833 types of the corresponding nontype parameters as specified in
18834 _temp.arg.nontype_, otherwise type deduction fails.
18836 All references in the function type of the function template
18837 to the corresponding template parameters are replaced by the
18838 specified template argument values. If a substitution in a
18839 template parameter or in the function type of the function
18840 template results in an invalid type, type deduction fails. */
18851 explicit_targs);
18853 /* Adjust any explicit template arguments before entering the
18854 substitution context. */
18855 explicit_targs
18857 complain,
18863 /* Substitute the explicit args into the function type. This is
18864 necessary so that, for instance, explicitly declared function
18865 arguments can match null pointed constants. If we were given
18866 an incomplete set of explicit args, we must not do semantic
18867 processing during substitution as we could create partial
18868 instantiations. */
18870 {
18875 /* Dig out the actual parm. */
18878 {
18881 }
18883 {
18886 }
18889 /* No explicit argument for this template parameter. */
18893 {
18894 /* Mark the argument pack as "incomplete". We could
18895 still deduce more arguments during unification.
18896 We remove this mark in type_unification_real. */
18898 {
18902 }
18904 /* We have some incomplete argument packs. */
18906 }
18907 }
18911 {
18914 }
18917 /* Ignore any access checks; we'll see them again in
18918 instantiate_template and they might have the wrong
18919 access path at this point. */
18931 /* Place the explicitly specified arguments in TARGS. */
18935 }
18937 /* Never do unification on the 'this' parameter. */
18941 {
18942 /* We're deducing for a call to the result of a template conversion
18943 function. The parms we really want are in return_type. */
18947 }
18949 {
18958 }
18960 /* We allow incomplete unification without an error message here
18961 because the standard doesn't seem to explicitly prohibit it. Our
18962 callers must be ready to deal with unification failures in any
18963 event. */
18966 /* If we aren't explaining yet, push tinst context so we can see where
18967 any errors (e.g. from class instantiations triggered by instantiation
18968 of default template arguments) come from. If we are explaining, this
18969 context is redundant. */
18971 {
18974 }
18976 /* type_unification_real will pass back any access checks from default
18977 template argument substitution. */
18989 /* Now that we have bindings for all of the template arguments,
18990 ensure that the arguments deduced for the template template
18991 parameters have compatible template parameter lists. We cannot
18992 check this property before we have deduced all template
18993 arguments, because the template parameter types of a template
18994 template parameter might depend on prior template parameters
18995 deduced after the template template parameter. The following
18996 ill-formed example illustrates this issue:
18998 template<typename T, template<T> class C> void f(C<5>, T);
19000 template<int N> struct X {};
19002 void g() {
19003 f(X<5>(), 5l); // error: template argument deduction fails
19004 }
19006 The template parameter list of 'C' depends on the template type
19007 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19008 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19009 time that we deduce 'C'. */
19012 {
19015 }
19017 /* All is well so far. Now, check:
19019 [temp.deduct]
19021 When all template arguments have been deduced, all uses of
19022 template parameters in nondeduced contexts are replaced with
19023 the corresponding deduced argument values. If the
19024 substitution results in an invalid type, as described above,
19025 type deduction fails. */
19028 {
19031 }
19033 /* Also collect access checks from the instantiation. */
19046 /* Now perform any access checks encountered during substitution. */
19053 /* If we're looking for an exact match, check that what we got
19054 is indeed an exact match. It might not be if some template
19055 parameters are used in non-deduced contexts. But don't check
19056 for an exact match if we have dependent template arguments;
19057 in that case we're doing partial ordering, and we already know
19058 that we have two candidates that will provide the actual type. */
19060 {
19064 tree sarg
19070 {
19074 }
19075 }
19077 /* After doing deduction with the inherited constructor, actually return an
19078 instantiation of the inheriting constructor. */
19084 fail:
19087 {
19089 /* Reset once we're all the way out. */
19091 }
19093 /* We can't free this if a pending_template entry or last_error_tinst_level
19094 is pointing at it. */
19100 }
19102 /* Adjust types before performing type deduction, as described in
19103 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19104 sections are symmetric. PARM is the type of a function parameter
19105 or the return type of the conversion function. ARG is the type of
19106 the argument passed to the call, or the type of the value
19107 initialized with the result of the conversion function.
19108 ARG_EXPR is the original argument expression, which may be null. */
19110 static int
19114 tree arg_expr)
19115 {
19119 {
19124 /* Swap PARM and ARG throughout the remainder of this
19125 function; the handling is precisely symmetric since PARM
19126 will initialize ARG rather than vice versa. */
19131 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19132 too, but here handle it by stripping the reference from PARM
19133 rather than by adding it to ARG. */
19141 /* Nothing else to do in this case. */
19146 }
19149 {
19150 /* [temp.deduct.call]
19152 If P is not a reference type:
19154 --If A is an array type, the pointer type produced by the
19155 array-to-pointer standard conversion (_conv.array_) is
19156 used in place of A for type deduction; otherwise,
19158 --If A is a function type, the pointer type produced by
19159 the function-to-pointer standard conversion
19160 (_conv.func_) is used in place of A for type deduction;
19161 otherwise,
19163 --If A is a cv-qualified type, the top level
19164 cv-qualifiers of A's type are ignored for type
19165 deduction. */
19170 else
19172 }
19174 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19175 reference to a cv-unqualified template parameter that does not represent a
19176 template parameter of a class template (during class template argument
19177 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19178 an lvalue, the type "lvalue reference to A" is used in place of A for type
19179 deduction. */
19186 /* try_one_overload doesn't provide an arg_expr, but
19187 functions are always lvalues. */
19191 /* [temp.deduct.call]
19193 If P is a cv-qualified type, the top level cv-qualifiers
19194 of P's type are ignored for type deduction. If P is a
19195 reference type, the type referred to by P is used for
19196 type deduction. */
19199 {
19202 }
19204 /* DR 322. For conversion deduction, remove a reference type on parm
19205 too (which has been swapped into ARG). */
19210 }
19212 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19213 template which does contain any deducible template parameters; check if
19214 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19215 unify_one_argument. */
19217 static int
19220 {
19221 tree type;
19225 else
19232 {
19236 }
19238 {
19243 }
19247 else
19249 }
19253 /* Returns true iff the expression EXPR is one from which a template
19254 argument can be deduced. In other words, if it's an undecorated
19255 use of a template non-type parameter. */
19257 static bool
19259 {
19260 /* Strip implicit conversions. */
19264 }
19266 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19267 deducible way; that is, if it has a max value of <PARM> - 1. */
19269 static bool
19271 {
19280 }
19282 /* Returns true iff the template arguments ARGS use a template parameter
19283 in a deducible way. */
19285 static bool
19287 {
19289 {
19294 else
19295 {
19302 else
19304 }
19307 }
19309 }
19311 /* Returns true iff TYPE contains any deducible references to template
19312 parameters, as per 14.8.2.5. */
19314 static bool
19316 {
19320 /* T
19321 cv-list T
19322 TT<T>
19323 TT<i>
19324 TT<> */
19329 /* T*
19330 T&
19331 T&& */
19335 /* T[integer-constant ]
19336 type [i] */
19341 /* T type ::*
19342 type T::*
19343 T T::*
19344 T (type ::*)()
19345 type (T::*)()
19346 type (type ::*)(T)
19347 type (T::*)(T)
19348 T (type ::*)(T)
19349 T (T::*)()
19350 T (T::*)(T) */
19353 || (uses_deducible_template_parms
19356 /* template-name <T> (where template-name refers to a class template)
19357 template-name <i> (where template-name refers to a class template) */
19364 /* type (T)
19365 T()
19366 T(T) */
19369 {
19378 }
19381 }
19383 /* Subroutine of type_unification_real and unify_pack_expansion to
19384 handle unification of a single P/A pair. Parameters are as
19385 for those functions. */
19387 static int
19391 {
19398 /* We can't deduce anything from this, but we might get all the
19399 template args from other function args. */
19402 /* Implicit conversions (Clause 4) will be performed on a function
19403 argument to convert it to the type of the corresponding function
19404 parameter if the parameter type contains no template-parameters that
19405 participate in template argument deduction. */
19408 /* For function parameters with no deducible template parameters,
19409 just return. We'll check non-dependent conversions later. */
19413 {
19415 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19416 | UNIFY_ALLOW_MORE_CV_QUAL
19430 }
19432 /* We only do these transformations if this is the top-level
19433 parameter_type_list in a call or declaration matching; in other
19434 situations (nested function declarators, template argument lists) we
19435 won't be comparing a type to an expression, and we don't do any type
19436 adjustments. */
19438 {
19440 {
19443 {
19444 /* [temp.deduct.type] A template-argument can be
19445 deduced from a pointer to function or pointer
19446 to member function argument if the set of
19447 overloaded functions does not contain function
19448 templates and at most one of a set of
19449 overloaded functions provides a unique
19450 match. */
19454 /* If a unique match was not found, this is a
19455 non-deduced context, so we still succeed. */
19457 }
19463 }
19465 arg_strict |=
19467 }
19468 else
19473 /* For deduction from an init-list we need the actual list. */
19477 }
19479 /* for_each_template_parm callback that always returns 0. */
19481 static int
19483 {
19485 }
19487 /* for_each_template_parm any_fn callback to handle deduction of a template
19488 type argument from the type of an array bound. */
19490 static int
19492 {
19500 {
19506 }
19508 /* Keep walking. */
19510 }
19512 /* Try to deduce any not-yet-deduced template type arguments from the type of
19513 an array bound. This is handled separately from unify because 14.8.2.5 says
19514 "The type of a type parameter is only deduced from an array bound if it is
19515 not otherwise deduced." */
19517 static void
19519 {
19524 }
19526 /* Most parms like fn_type_unification.
19528 If SUBR is 1, we're being called recursively (to unify the
19529 arguments of a function or method parameter of a function
19530 template).
19532 CHECKS is a pointer to a vector of access checks encountered while
19533 substituting default template arguments. */
19535 static int
19537 tree full_targs,
19538 tree xparms,
19542 unification_kind_t strict,
19546 {
19551 tree parms;
19562 /* Reset the number of non-defaulted template arguments contained
19563 in TARGS. */
19566 again:
19574 {
19579 /* For a function parameter pack that occurs at the end of the
19580 parameter-declaration-list, the type A of each remaining
19581 argument of the call is compared with the type P of the
19582 declarator-id of the function parameter pack. */
19588 /* For a function parameter pack that does not occur at the
19589 end of the parameter-declaration-list, the type of the
19590 parameter pack is a non-deduced context. */
19597 explain_p))
19599 }
19604 {
19605 /* Unify the remaining arguments with the pack expansion type. */
19606 tree argvec;
19609 /* Allocate a TREE_VEC and copy in all of the arguments */
19614 /* Copy the parameter into parmvec. */
19620 /* Advance to the end of the list of parameters. */
19622 }
19624 /* Fail if we've reached the end of the parm list, and more args
19625 are present, and the parm list isn't variadic. */
19628 /* Fail if parms are left and they don't have default values and
19629 they aren't all deduced as empty packs (c++/57397). This is
19630 consistent with sufficient_parms_p. */
19633 {
19637 do
19638 {
19641 count++;
19643 }
19647 type_pack_p);
19648 }
19651 {
19652 tsubst_flags_t complain = (explain_p
19653 ? tf_warning_or_error
19658 {
19662 /* Clear the "incomplete" flags on all argument packs now so that
19663 substituting them into later default arguments works. */
19665 {
19668 }
19676 {
19681 }
19683 /* If this is an undeduced nontype parameter that depends on
19684 a type parameter, try another pass; its type may have been
19685 deduced from a later argument than the one from which
19686 this parameter can be deduced. */
19690 {
19693 }
19695 /* Core issue #226 (C++0x) [temp.deduct]:
19697 If a template argument has not been deduced, its
19698 default template argument, if any, is used.
19700 When we are in C++98 mode, TREE_PURPOSE will either
19701 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19702 to explicitly check cxx_dialect here. */
19704 /* OK, there is a default argument. Wait until after the
19705 conversion check to do substitution. */
19708 /* If the type parameter is a parameter pack, then it will
19709 be deduced to an empty parameter pack. */
19711 {
19712 tree arg;
19715 {
19718 }
19719 else
19726 }
19729 }
19731 /* DR 1391: All parameters have args, now check non-dependent parms for
19732 convertibility. */
19736 {
19742 /* For a function parameter pack that occurs at the end of the
19743 parameter-declaration-list, the type A of each remaining
19744 argument of the call is compared with the type P of the
19745 declarator-id of the function parameter pack. */
19751 /* For a function parameter pack that does not occur at the
19752 end of the parameter-declaration-list, the type of the
19753 parameter pack is a non-deduced context. */
19762 explain_p))
19764 }
19766 /* Now substitute into the default template arguments. */
19768 {
19792 else
19800 {
19802 /* The position of the first default template argument,
19803 is also the number of non-defaulted arguments in TARGS.
19804 Record that. */
19807 }
19808 }
19812 }
19818 }
19820 /* Subroutine of type_unification_real. Args are like the variables
19821 at the call site. ARG is an overloaded function (or template-id);
19822 we try deducing template args from each of the overloads, and if
19823 only one succeeds, we go with that. Modifies TARGS and returns
19824 true on success. */
19826 static bool
19828 tree targs,
19829 tree parm,
19830 tree arg,
19831 unification_kind_t strict,
19834 {
19841 {
19844 }
19845 else
19849 /* Handle `&x' where `x' is some static or non-static member
19850 function name. */
19856 /* Strip baselink information. */
19861 {
19862 /* If we got some explicit template args, we need to plug them into
19863 the affected templates before we try to unify, in case the
19864 explicit args will completely resolve the templates in question. */
19871 {
19884 {
19889 {
19892 }
19893 }
19896 }
19897 /* If no templates (or more than one) are fully resolved by the
19898 explicit arguments, this template-id is a non-deduced context; it
19899 could still be OK if we deduce all template arguments for the
19900 enclosing call through other arguments. */
19903 }
19906 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19907 -- but the deduction does not succeed because the expression is
19908 not just the function on its own. */
19910 else
19912 {
19917 {
19920 }
19921 }
19923 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19924 to function or pointer to member function argument if the set of
19925 overloaded functions does not contain function templates and at most
19926 one of a set of overloaded functions provides a unique match.
19928 So if we found multiple possibilities, we return success but don't
19929 deduce anything. */
19932 {
19936 {
19941 /* Don't forget explicit template arguments in a pack. */
19945 }
19946 }
19951 }
19953 /* Core DR 115: In contexts where deduction is done and fails, or in
19954 contexts where deduction is not done, if a template argument list is
19955 specified and it, along with any default template arguments, identifies
19956 a single function template specialization, then the template-id is an
19957 lvalue for the function template specialization. */
19959 tree
19961 {
19974 {
19977 }
19979 {
19982 }
19984 {
19987 }
19990 {
19994 /* If we got some explicit template args, we need to plug them into
19995 the affected templates before we try to unify, in case the
19996 explicit args will completely resolve the templates in question. */
20004 {
20017 {
20020 {
20023 }
20025 {
20028 }
20029 }
20030 }
20032 {
20040 {
20041 tree base
20044 }
20048 }
20050 /* There were no good options and at least one bad one, so let the
20051 user know what the problem is. */
20053 }
20055 }
20057 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20058 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20059 different overloads deduce different arguments for a given parm.
20060 ADDR_P is true if the expression for which deduction is being
20061 performed was of the form "& fn" rather than simply "fn".
20063 Returns 1 on success. */
20065 static int
20067 tree orig_targs,
20068 tree targs,
20069 tree parm,
20070 tree arg,
20071 unification_kind_t strict,
20075 {
20077 tree tempargs;
20083 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20084 to function or pointer to member function argument if the set of
20085 overloaded functions does not contain function templates and at most
20086 one of a set of overloaded functions provides a unique match.
20088 So if this is a template, just return success. */
20100 /* We don't copy orig_targs for this because if we have already deduced
20101 some template args from previous args, unify would complain when we
20102 try to deduce a template parameter for the same argument, even though
20103 there isn't really a conflict. */
20110 /* First make sure we didn't deduce anything that conflicts with
20111 explicitly specified args. */
20113 {
20120 /* Since we're unifying against ourselves, we will fill in
20121 template args used in the function parm list with our own
20122 template parms. Discard them. */
20125 {
20126 /* Check that the argument at each index of the deduced argument pack
20127 is equivalent to the corresponding explicitly specified argument.
20128 We may have deduced more arguments than were explicitly specified,
20129 and that's OK. */
20131 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20132 that's wrong if we deduce the same argument pack from multiple
20133 function arguments: it's only incomplete the first time. */
20146 }
20149 }
20152 {
20157 }
20160 }
20162 /* PARM is a template class (perhaps with unbound template
20163 parameters). ARG is a fully instantiated type. If ARG can be
20164 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20165 TARGS are as for unify. */
20167 static tree
20170 {
20171 tree copy_of_targs;
20181 /* We need to make a new template argument vector for the call to
20182 unify. If we used TARGS, we'd clutter it up with the result of
20183 the attempted unification, even if this class didn't work out.
20184 We also don't want to commit ourselves to all the unifications
20185 we've already done, since unification is supposed to be done on
20186 an argument-by-argument basis. In other words, consider the
20187 following pathological case:
20189 template <int I, int J, int K>
20190 struct S {};
20192 template <int I, int J>
20193 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20195 template <int I, int J, int K>
20196 void f(S<I, J, K>, S<I, I, I>);
20198 void g() {
20199 S<0, 0, 0> s0;
20200 S<0, 1, 2> s2;
20202 f(s0, s2);
20203 }
20205 Now, by the time we consider the unification involving `s2', we
20206 already know that we must have `f<0, 0, 0>'. But, even though
20207 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20208 because there are two ways to unify base classes of S<0, 1, 2>
20209 with S<I, I, I>. If we kept the already deduced knowledge, we
20210 would reject the possibility I=1. */
20214 {
20218 }
20220 /* If unification failed, we're done. */
20226 }
20228 /* Given a template type PARM and a class type ARG, find the unique
20229 base type in ARG that is an instance of PARM. We do not examine
20230 ARG itself; only its base-classes. If there is not exactly one
20231 appropriate base class, return NULL_TREE. PARM may be the type of
20232 a partial specialization, as well as a plain template type. Used
20233 by unify. */
20235 static enum template_base_result
20238 {
20240 tree binfo;
20246 {
20247 /* The type could not be completed. */
20250 }
20252 /* Walk in inheritance graph order. The search order is not
20253 important, and this avoids multiple walks of virtual bases. */
20255 {
20260 {
20261 /* If there is more than one satisfactory baseclass, then:
20263 [temp.deduct.call]
20265 If they yield more than one possible deduced A, the type
20266 deduction fails.
20268 applies. */
20270 {
20273 }
20276 }
20277 }
20281 }
20283 /* Returns the level of DECL, which declares a template parameter. */
20285 static int
20287 {
20289 {
20299 }
20301 }
20303 /* Decide whether ARG can be unified with PARM, considering only the
20304 cv-qualifiers of each type, given STRICT as documented for unify.
20305 Returns nonzero iff the unification is OK on that basis. */
20307 static int
20309 {
20315 {
20316 /* Although a CVR qualifier is ignored when being applied to a
20317 substituted template parameter ([8.3.2]/1 for example), that
20318 does not allow us to unify "const T" with "int&" because both
20319 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20320 It is ok when we're allowing additional CV qualifiers
20321 at the outer level [14.8.2.1]/3,1st bullet. */
20331 }
20342 }
20344 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20345 void
20347 {
20351 {
20354 }
20355 else
20356 {
20359 }
20360 }
20362 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20363 do { \
20364 if (unify (TP, TA, P, A, S, EP)) \
20365 return 1; \
20366 } while (0)
20368 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20369 expansion at the end of PACKED_PARMS. Returns 0 if the type
20370 deduction succeeds, 1 otherwise. STRICT is the same as in
20371 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20372 function call argument list. We'll need to adjust the arguments to make them
20373 types. SUBR tells us if this is from a recursive call to
20374 type_unification_real, or for comparing two template argument
20375 lists. */
20377 static int
20381 {
20382 tree parm
20388 /* Add in any args remembered from an earlier partial instantiation. */
20396 /* Determine the parameter packs we will be deducing from the
20397 pattern, and record their current deductions. */
20400 {
20404 /* Determine the index and level of this parameter pack. */
20409 /* Keep track of the parameter packs and their corresponding
20410 argument packs. */
20413 }
20415 /* Loop through all of the arguments that have not yet been
20416 unified and unify each with the pattern. */
20418 {
20419 tree parm;
20423 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20424 or the element of its argument pack at the current index if
20425 this argument was explicitly specified. */
20427 {
20436 {
20439 }
20441 }
20443 /* If we had explicit template arguments, substitute them into the
20444 pattern before deduction. */
20446 {
20447 /* Some arguments might still be unspecified or dependent. */
20455 NULL_TREE);
20460 }
20461 else
20464 /* Unify the pattern with the current argument. */
20466 explain_p))
20469 /* For each parameter pack, collect the deduced value. */
20471 {
20477 }
20478 }
20480 /* Verify that the results of unification with the parameter packs
20481 produce results consistent with what we've seen before, and make
20482 the deduced argument packs available. */
20484 {
20491 /* By default keep the original deduced argument pack.
20492 If necessary, more specific code is going to update the
20493 resulting deduced argument later down in this function. */
20497 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20498 actually deduce anything. */
20506 {
20507 /* If we had fewer function args than explicit template args,
20508 just use the explicits. */
20513 }
20516 {
20517 tree result;
20518 /* Build the deduced *_ARGUMENT_PACK. */
20520 {
20523 }
20524 else
20529 /* Note the deduced argument packs for this parameter
20530 pack. */
20532 }
20536 {
20537 /* We only had the explicitly-provided arguments before, but
20538 now we have a complete set of arguments. */
20544 }
20545 else
20546 {
20552 /* Inconsistent unification of this parameter pack. */
20554 bad_old_arg,
20555 bad_new_arg);
20556 }
20557 }
20560 }
20562 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20563 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20564 parameters and return value are as for unify. */
20566 static int
20570 {
20571 tree parm_max;
20572 tree arg_max;
20576 /* Our representation of array types uses "N - 1" as the
20577 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20578 not an integer constant. We cannot unify arbitrarily
20579 complex expressions, so we eliminate the MINUS_EXPRs
20580 here. */
20584 {
20587 }
20591 {
20592 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20593 trying to unify the type of a variable with the type
20594 of a template parameter. For example:
20596 template <unsigned int N>
20597 void f (char (&) [N]);
20598 int g();
20599 void h(int i) {
20600 char a[g(i)];
20601 f(a);
20602 }
20604 Here, the type of the ARG will be "int [g(i)]", and
20605 may be a SAVE_EXPR, etc. */
20609 }
20611 /* If only one of the bounds used a MINUS_EXPR, compensate
20612 by adding one to the other bound. */
20615 integer_type_node,
20616 parm_max,
20617 integer_one_node);
20620 integer_type_node,
20621 arg_max,
20622 integer_one_node);
20626 }
20628 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20632 static pa_kind_t
20634 {
20643 else
20645 }
20647 /* Deduce the value of template parameters. TPARMS is the (innermost)
20648 set of template parameters to a template. TARGS is the bindings
20649 for those template parameters, as determined thus far; TARGS may
20650 include template arguments for outer levels of template parameters
20651 as well. PARM is a parameter to a template function, or a
20652 subcomponent of that parameter; ARG is the corresponding argument.
20653 This function attempts to match PARM with ARG in a manner
20654 consistent with the existing assignments in TARGS. If more values
20655 are deduced, then TARGS is updated.
20657 Returns 0 if the type deduction succeeds, 1 otherwise. The
20658 parameter STRICT is a bitwise or of the following flags:
20660 UNIFY_ALLOW_NONE:
20661 Require an exact match between PARM and ARG.
20662 UNIFY_ALLOW_MORE_CV_QUAL:
20663 Allow the deduced ARG to be more cv-qualified (by qualification
20664 conversion) than ARG.
20665 UNIFY_ALLOW_LESS_CV_QUAL:
20666 Allow the deduced ARG to be less cv-qualified than ARG.
20667 UNIFY_ALLOW_DERIVED:
20668 Allow the deduced ARG to be a template base class of ARG,
20669 or a pointer to a template base class of the type pointed to by
20670 ARG.
20671 UNIFY_ALLOW_INTEGER:
20672 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20673 case for more information.
20674 UNIFY_ALLOW_OUTER_LEVEL:
20675 This is the outermost level of a deduction. Used to determine validity
20676 of qualification conversions. A valid qualification conversion must
20677 have const qualified pointers leading up to the inner type which
20678 requires additional CV quals, except at the outer level, where const
20679 is not required [conv.qual]. It would be normal to set this flag in
20680 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20681 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20682 This is the outermost level of a deduction, and PARM can be more CV
20683 qualified at this point.
20684 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20685 This is the outermost level of a deduction, and PARM can be less CV
20686 qualified at this point. */
20688 static int
20691 {
20693 tree targ;
20694 tree tparm;
20696 tsubst_flags_t complain = (explain_p
20697 ? tf_warning_or_error
20700 /* I don't think this will do the right thing with respect to types.
20701 But the only case I've seen it in so far has been array bounds, where
20702 signedness is the only information lost, and I think that will be
20703 okay. */
20711 /* We can't deduce anything from this, but we might get all the
20712 template args from other function args. */
20718 /* If PARM uses template parameters, then we can't bail out here,
20719 even if ARG == PARM, since we won't record unifications for the
20720 template parameters. We might need them if we're trying to
20721 figure out which of two things is more specialized. */
20725 /* Handle init lists early, so the rest of the function can assume
20726 we're dealing with a type. */
20728 {
20733 /* Replace T with std::initializer_list<T> for deduction. */
20740 /* We can only deduce from an initializer list argument if the
20741 parameter is std::initializer_list or an array; otherwise this
20742 is a non-deduced context. */
20747 else
20748 {
20750 /* Deduction is defined in terms of a single type, so just punt
20751 on the (bizarre) std::initializer_list<T...>. */
20754 }
20757 {
20764 {
20768 /* It should only be possible to get here for a call. */
20770 elt_strict |= maybe_adjust_types_for_deduction
20773 }
20776 explain_p);
20777 }
20781 {
20782 /* Also deduce from the length of the initializer list. */
20789 }
20791 /* If the std::initializer_list<T> deduction worked, replace the
20792 deduced A with std::initializer_list<A>. */
20794 {
20799 }
20801 }
20803 /* If parm and arg aren't the same kind of thing (template, type, or
20804 expression), fail early. */
20808 /* Immediately reject some pairs that won't unify because of
20809 cv-qualification mismatches. */
20812 /* It is the elements of the array which hold the cv quals of an array
20813 type, and the elements might be template type parms. We'll check
20814 when we recurse. */
20816 /* We check the cv-qualifiers when unifying with template type
20817 parameters below. We want to allow ARG `const T' to unify with
20818 PARM `T' for example, when computing which of two templates
20819 is more specialized, for example. */
20833 {
20837 /* In a type which contains a nested-name-specifier, template
20838 argument values cannot be deduced for template parameters used
20839 within the nested-name-specifier. */
20851 /* The PARM is not one we're trying to unify. Just check
20852 to see if it matches ARG. */
20853 {
20858 else
20860 }
20867 /* Check for mixed types and values. */
20875 {
20878 {
20879 /* First try to match ARG directly. */
20881 explain_p);
20883 {
20884 /* Otherwise, look for a suitable base of ARG, as below. */
20891 }
20892 }
20893 /* ARG must be constructed from a template class or a template
20894 template parameter. */
20899 /* Deduce arguments T, i from TT<T> or TT<i>. */
20905 /* Fall through to deduce template name. */
20906 }
20910 {
20911 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20913 /* Simple cases: Value already set, does match or doesn't. */
20918 }
20919 else
20920 {
20921 /* If PARM is `const T' and ARG is only `int', we don't have
20922 a match unless we are allowing additional qualification.
20923 If ARG is `const int' and PARM is just `T' that's OK;
20924 that binds `const int' to `T'. */
20929 /* Consider the case where ARG is `const volatile int' and
20930 PARM is `const T'. Then, T should be `volatile int'. */
20931 arg = cp_build_qualified_type_real
20936 /* Simple cases: Value already set, does match or doesn't. */
20942 /* Make sure that ARG is not a variable-sized array. (Note
20943 that were talking about variable-sized arrays (like
20944 `int[n]'), rather than arrays of unknown size (like
20945 `int[]').) We'll get very confused by such a type since
20946 the bound of the array is not constant, and therefore
20947 not mangleable. Besides, such types are not allowed in
20948 ISO C++, so we can do as we please here. We do allow
20949 them for 'auto' deduction, since that isn't ABI-exposed. */
20953 /* Strip typedefs as in convert_template_argument. */
20955 }
20957 /* If ARG is a parameter pack or an expansion, we cannot unify
20958 against it unless PARM is also a parameter pack. */
20963 /* If the argument deduction results is a METHOD_TYPE,
20964 then there is a problem.
20965 METHOD_TYPE doesn't map to any real C++ type the result of
20966 the deduction can not be of that type. */
20980 {
20981 /* The PARM is not one we're trying to unify. Just check
20982 to see if it matches ARG. */
20988 }
20994 {
20998 /* We're deducing from an array bound, the type doesn't matter. */
21004 }
21006 /* [temp.deduct.type] If, in the declaration of a function template
21007 with a non-type template-parameter, the non-type
21008 template-parameter is used in an expression in the function
21009 parameter-list and, if the corresponding template-argument is
21010 deduced, the template-argument type shall match the type of the
21011 template-parameter exactly, except that a template-argument
21012 deduced from an array bound may be of any integral type.
21013 The non-type parameter might use already deduced type parameters. */
21018 {
21022 }
21025 /* Template-parameter dependent expression. Just accept it for now.
21026 It will later be processed in convert_template_argument. */
21027 ;
21033 /* Convert the ARG to the type of PARM; the deduced non-type
21034 template argument must exactly match the types of the
21035 corresponding parameter. */
21038 {
21039 /* We haven't deduced the type of this parameter yet. */
21041 /* We deduce from array bounds in try_array_deduction. */
21043 {
21044 /* Deduce it from the non-type argument. */
21049 }
21050 else
21051 /* Try again later. */
21053 }
21054 else
21057 /* If ARG is a parameter pack or an expansion, we cannot unify
21058 against it unless PARM is also a parameter pack. */
21063 {
21066 }
21071 {
21072 /* A pointer-to-member constant can be unified only with
21073 another constant. */
21077 /* Just unify the class member. It would be useless (and possibly
21078 wrong, depending on the strict flags) to unify also
21079 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21080 arg refer to the same variable, even if through different
21081 classes. For instance:
21083 struct A { int x; };
21084 struct B : A { };
21086 Unification of &A::x and &B::x must succeed. */
21089 }
21092 {
21096 /* [temp.deduct.call]
21098 A can be another pointer or pointer to member type that can
21099 be converted to the deduced A via a qualification
21100 conversion (_conv.qual_).
21102 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21103 This will allow for additional cv-qualification of the
21104 pointed-to types if appropriate. */
21107 /* The derived-to-base conversion only persists through one
21108 level of pointers. */
21113 }
21145 /* We have already checked cv-qualification at the top of the
21146 function. */
21150 /* As far as unification is concerned, this wins. Later checks
21151 will invalidate it if necessary. */
21154 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21155 /* Type INTEGER_CST can come from ordinary constant template args. */
21167 {
21177 /* Check for pack expansions in the parameters. */
21179 {
21181 {
21183 /* We can unify against something with a trailing
21184 parameter pack. */
21186 else
21187 /* [temp.deduct.type]/9: If the template argument list of
21188 P contains a pack expansion that is not the last
21189 template argument, the entire template argument list
21190 is a non-deduced context. */
21192 }
21193 }
21195 /* If we don't have enough arguments to satisfy the parameters
21196 (not counting the pack expression at the end), or we have
21197 too many arguments for a parameter list that doesn't end in
21198 a pack expression, we can't unify. */
21204 /* Unify all of the parameters that precede the (optional)
21205 pack expression. */
21207 {
21212 }
21215 DEDUCE_EXACT,
21218 }
21226 {
21234 }
21239 {
21243 {
21244 /* First, we try to unify the PARM and ARG directly. */
21249 {
21250 /* Fallback to the special case allowed in
21251 [temp.deduct.call]:
21253 If P is a class, and P has the form
21254 template-id, then A can be a derived class of
21255 the deduced A. Likewise, if P is a pointer to
21256 a class of the form template-id, A can be a
21257 pointer to a derived class pointed to by the
21258 deduced A. */
21264 {
21265 /* Don't give the derived diagnostic if we're
21266 already dealing with the same template. */
21267 bool same_template
21273 }
21274 }
21275 }
21279 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21280 Then, we should unify `int' and `U'. */
21282 else
21283 /* There's no chance of unification succeeding. */
21288 }
21295 {
21298 tree a;
21304 /* CV qualifications for methods can never be deduced, they must
21305 match exactly. We need to check them explicitly here,
21306 because type_unification_real treats them as any other
21307 cv-qualified parameter. */
21309 && (!check_cv_quals_for_unify
21337 {
21349 }
21352 }
21355 /* Unify a pointer to member with a pointer to member function, which
21356 deduces the type of the member as a function type. */
21358 {
21359 /* Check top-level cv qualifiers */
21367 /* Determine the type of the function we are unifying against. */
21371 }
21390 /* Matched cases are handled by the ARG == PARM test above. */
21394 /* We might get a variable as a non-type template argument in parm if the
21395 corresponding parameter is type-dependent. Make any necessary
21396 adjustments based on whether arg is a reference. */
21400 {
21405 }
21406 /* Now use the normal expression code to check whether they match. */
21417 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21418 or UNDERLYING_TYPE nodes. */
21422 /* Unification fails if we hit an error node. */
21427 {
21437 }
21438 /* FALLTHRU */
21441 /* An unresolved overload is a nondeduced context. */
21445 expr:
21446 /* We must be looking at an expression. This can happen with
21447 something like:
21449 template <int I>
21450 void foo(S<I>, S<I + 2>);
21452 This is a "nondeduced context":
21454 [deduct.type]
21456 The nondeduced contexts are:
21458 --A type that is a template-id in which one or more of
21459 the template-arguments is an expression that references
21460 a template-parameter.
21462 In these cases, we assume deduction succeeded, but don't
21463 actually infer any unifications. */
21468 else
21470 }
21471 }
21472 #undef RECUR_AND_CHECK_FAILURE
21473 \f
21474 /* Note that DECL can be defined in this translation unit, if
21475 required. */
21477 static void
21479 {
21480 tree clone;
21484 }
21486 /* Called if RESULT is explicitly instantiated, or is a member of an
21487 explicitly instantiated class. */
21489 void
21491 {
21494 /* If this entity has already been written out, it's too late to
21495 make any modifications. */
21499 /* For anonymous namespace we don't need to do anything. */
21501 {
21504 }
21507 /* The TREE_PUBLIC flag for function declarations will have been
21508 set correctly by tsubst. */
21511 /* This might have been set by an earlier implicit instantiation. */
21516 else
21517 {
21520 /* Always make artificials weak. */
21523 /* For WIN32 we also want to put explicit instantiations in
21524 linkonce sections. */
21527 }
21529 /* If EXTERN_P, then this function will not be emitted -- unless
21530 followed by an explicit instantiation, at which point its linkage
21531 will be adjusted. If !EXTERN_P, then this function will be
21532 emitted here. In neither circumstance do we want
21533 import_export_decl to adjust the linkage. */
21535 }
21537 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21538 important template arguments. If any are missing, we check whether
21539 they're important by using error_mark_node for substituting into any
21540 args that were used for partial ordering (the ones between ARGS and END)
21541 and seeing if it bubbles up. */
21543 static bool
21545 {
21550 {
21553 }
21555 {
21559 }
21561 }
21563 /* Given two function templates PAT1 and PAT2, return:
21565 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21566 -1 if PAT2 is more specialized than PAT1.
21567 0 if neither is more specialized.
21569 LEN indicates the number of parameters we should consider
21570 (defaulted parameters should not be considered).
21572 The 1998 std underspecified function template partial ordering, and
21573 DR214 addresses the issue. We take pairs of arguments, one from
21574 each of the templates, and deduce them against each other. One of
21575 the templates will be more specialized if all the *other*
21576 template's arguments deduce against its arguments and at least one
21577 of its arguments *does* *not* deduce against the other template's
21578 corresponding argument. Deduction is done as for class templates.
21579 The arguments used in deduction have reference and top level cv
21580 qualifiers removed. Iff both arguments were originally reference
21581 types *and* deduction succeeds in both directions, an lvalue reference
21582 wins against an rvalue reference and otherwise the template
21583 with the more cv-qualified argument wins for that pairing (if
21584 neither is more cv-qualified, they both are equal). Unlike regular
21585 deduction, after all the arguments have been deduced in this way,
21586 we do *not* verify the deduced template argument values can be
21587 substituted into non-deduced contexts.
21589 The logic can be a bit confusing here, because we look at deduce1 and
21590 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21591 can find template arguments for pat1 to make arg1 look like arg2, that
21592 means that arg2 is at least as specialized as arg1. */
21594 int
21596 {
21609 /* Remove the this parameter from non-static member functions. If
21610 one is a non-static member function and the other is not a static
21611 member function, remove the first parameter from that function
21612 also. This situation occurs for operator functions where we
21613 locate both a member function (with this pointer) and non-member
21614 operator (with explicit first operand). */
21616 {
21621 }
21623 {
21626 {
21627 len--;
21629 }
21630 }
21632 /* If only one is a conversion operator, they are unordered. */
21636 /* Consider the return type for a conversion function */
21638 {
21641 len++;
21642 }
21644 processing_template_decl++;
21650 /* Stop when an ellipsis is seen. */
21652 {
21663 {
21664 /* When both arguments are pack expansions, we need only
21665 unify the patterns themselves. */
21669 /* This is the last comparison we need to do. */
21671 }
21673 /* DR 1847: If a particular P contains no template-parameters that
21674 participate in template argument deduction, that P is not used to
21675 determine the ordering. */
21681 {
21685 }
21688 {
21692 }
21698 {
21704 /* Setup the parameter vector, which contains only ARG1. */
21707 /* Setup the argument vector, which contains the remaining
21708 arguments. */
21717 /* We cannot deduce in the other direction, because ARG1 is
21718 a pack expansion but ARG2 is not. */
21720 }
21722 {
21728 /* Setup the parameter vector, which contains only ARG1. */
21731 /* Setup the argument vector, which contains the remaining
21732 arguments. */
21741 /* We cannot deduce in the other direction, because ARG2 is
21742 a pack expansion but ARG1 is not.*/
21744 }
21746 else
21747 {
21748 /* The normal case, where neither argument is a pack
21749 expansion. */
21756 }
21758 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21759 arg2, then arg2 is not as specialized as arg1. */
21765 /* "If, for a given type, deduction succeeds in both directions
21766 (i.e., the types are identical after the transformations above)
21767 and both P and A were reference types (before being replaced with
21768 the type referred to above):
21769 - if the type from the argument template was an lvalue reference and
21770 the type from the parameter template was not, the argument type is
21771 considered to be more specialized than the other; otherwise,
21772 - if the type from the argument template is more cv-qualified
21773 than the type from the parameter template (as described above),
21774 the argument type is considered to be more specialized than the other;
21775 otherwise,
21776 - neither type is more specialized than the other." */
21779 {
21781 {
21784 else
21786 }
21788 {
21793 }
21794 }
21797 /* We've failed to deduce something in either direction.
21798 These must be unordered. */
21801 next:
21805 /* We have already processed all of the arguments in our
21806 handing of the pack expansion type. */
21811 }
21813 /* "In most cases, all template parameters must have values in order for
21814 deduction to succeed, but for partial ordering purposes a template
21815 parameter may remain without a value provided it is not used in the
21816 types being used for partial ordering."
21818 Thus, if we are missing any of the targs1 we need to substitute into
21819 origs1, then pat2 is not as specialized as pat1. This can happen when
21820 there is a nondeduced context. */
21826 processing_template_decl--;
21828 /* If both deductions succeed, the partial ordering selects the more
21829 constrained template. */
21831 {
21836 }
21838 /* All things being equal, if the next argument is a pack expansion
21839 for one function but not for the other, prefer the
21840 non-variadic function. FIXME this is bogus; see c++/41958. */
21844 {
21847 }
21853 else
21855 }
21857 /* Determine which of two partial specializations of TMPL is more
21858 specialized.
21860 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21861 to the first partial specialization. The TREE_PURPOSE is the
21862 innermost set of template parameters for the partial
21863 specialization. PAT2 is similar, but for the second template.
21865 Return 1 if the first partial specialization is more specialized;
21866 -1 if the second is more specialized; 0 if neither is more
21867 specialized.
21869 See [temp.class.order] for information about determining which of
21870 two templates is more specialized. */
21872 static int
21874 {
21875 tree targs;
21884 /* Just like what happens for functions, if we are ordering between
21885 different template specializations, we may encounter dependent
21886 types in the arguments, and we need our dependency check functions
21887 to behave correctly. */
21891 {
21894 }
21898 {
21901 }
21904 /* If both deductions succeed, the partial ordering selects the more
21905 constrained template. */
21909 /* In the case of a tie where at least one of the templates
21910 has a parameter pack at the end, the template with the most
21911 non-packed parameters wins. */
21913 && any_deductions
21916 {
21922 /* We don't count the pack expansion at the end. */
21932 }
21935 }
21937 /* Return the template arguments that will produce the function signature
21938 DECL from the function template FN, with the explicit template
21939 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21940 also match. Return NULL_TREE if no satisfactory arguments could be
21941 found. */
21943 static tree
21945 {
21949 tree decl_arg_types;
21952 tree arg;
21956 /* Never do unification on the 'this' parameter. */
21977 }
21979 /* Return the innermost template arguments that, when applied to a partial
21980 specialization SPEC_TMPL of TMPL, yield the ARGS.
21982 For example, suppose we have:
21984 template <class T, class U> struct S {};
21985 template <class T> struct S<T*, int> {};
21987 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21988 partial specialization and the ARGS will be {double*, int}. The resulting
21989 vector will be {double}, indicating that `T' is bound to `double'. */
21991 static tree
21993 {
21995 tree spec_args
21998 tree deduced_args;
21999 tree innermost_deduced_args;
22003 {
22007 innermost_deduced_args);
22008 }
22009 else
22013 again:
22022 {
22024 {
22030 }
22032 }
22036 {
22039 }
22041 /* Verify that nondeduced template arguments agree with the type
22042 obtained from argument deduction.
22044 For example:
22046 struct A { typedef int X; };
22047 template <class T, class U> struct C {};
22048 template <class T> struct C<T, typename T::X> {};
22050 Then with the instantiation `C<A, int>', we can deduce that
22051 `T' is `A' but unify () does not check whether `typename T::X'
22052 is `int'. */
22063 /* We only need to check the innermost arguments; the other
22064 arguments will always agree. */
22069 /* Now that we have bindings for all of the template arguments,
22070 ensure that the arguments deduced for the template template
22071 parameters have compatible template parameter lists. See the use
22072 of template_template_parm_bindings_ok_p in fn_type_unification
22073 for more information. */
22078 }
22080 // Compare two function templates T1 and T2 by deducing bindings
22081 // from one against the other. If both deductions succeed, compare
22082 // constraints to see which is more constrained.
22083 static int
22085 {
22090 {
22093 }
22096 {
22099 }
22101 // If both deductions succeed, then one may be more constrained.
22106 }
22108 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22109 Return the TREE_LIST node with the most specialized template, if
22110 any. If there is no most specialized template, the error_mark_node
22111 is returned.
22113 Note that this function does not look at, or modify, the
22114 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22115 returned is one of the elements of INSTANTIATIONS, callers may
22116 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22117 and retrieve it from the value returned. */
22119 tree
22121 {
22128 {
22134 {
22135 /* Equally specialized, move to next function. If there
22136 is no next function, nothing's most specialized. */
22141 }
22142 }
22145 /* Now verify that champ is better than everything earlier in the
22146 instantiation list. */
22149 {
22152 }
22153 }
22155 processing_template_decl--;
22161 }
22163 /* If DECL is a specialization of some template, return the most
22164 general such template. Otherwise, returns NULL_TREE.
22166 For example, given:
22168 template <class T> struct S { template <class U> void f(U); };
22170 if TMPL is `template <class U> void S<int>::f(U)' this will return
22171 the full template. This function will not trace past partial
22172 specializations, however. For example, given in addition:
22174 template <class T> struct S<T*> { template <class U> void f(U); };
22176 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22177 `template <class T> template <class U> S<T*>::f(U)'. */
22179 tree
22181 {
22183 {
22186 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22187 template friend, or a FIELD_DECL for a capture pack. */
22190 }
22192 /* Look for more and more general templates. */
22194 {
22195 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22196 (See cp-tree.h for details.) */
22205 /* Stop if we run into an explicitly specialized class template. */
22212 }
22215 }
22217 /* Return the most specialized of the template partial specializations
22218 which can produce TARGET, a specialization of some class or variable
22219 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22220 a TEMPLATE_DECL node corresponding to the partial specialization, while
22221 the TREE_PURPOSE is the set of template arguments that must be
22222 substituted into the template pattern in order to generate TARGET.
22224 If the choice of partial specialization is ambiguous, a diagnostic
22225 is issued, and the error_mark_node is returned. If there are no
22226 partial specializations matching TARGET, then NULL_TREE is
22227 returned, indicating that the primary template should be used. */
22229 static tree
22231 {
22233 tree t;
22234 tree champ;
22241 {
22245 }
22247 {
22250 }
22252 {
22256 }
22257 else
22262 /* For determining which partial specialization to use, only the
22263 innermost args are interesting. */
22265 {
22268 }
22271 {
22272 tree spec_args;
22276 {
22277 /* Substitute in the template args from the enclosing class. */
22281 }
22288 {
22292 /* Keep the candidate only if the constraints are satisfied,
22293 or if we're not compiling with concepts. */
22296 {
22299 }
22300 }
22301 }
22311 {
22314 ;
22315 else
22316 {
22318 {
22321 {
22324 }
22325 }
22327 }
22328 }
22332 {
22335 {
22338 }
22339 }
22342 {
22349 else
22353 {
22358 }
22361 }
22364 }
22366 /* Explicitly instantiate DECL. */
22368 void
22370 {
22375 /* An error occurred, for which grokdeclarator has already issued
22376 an appropriate message. */
22379 {
22382 }
22388 {
22389 /* There is an asymmetry here in the way VAR_DECLs and
22390 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22391 the latter, the DECL we get back will be marked as a
22392 template instantiation, and the appropriate
22393 DECL_TEMPLATE_INFO will be set up. This does not happen for
22394 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22395 should handle VAR_DECLs as it currently handles
22396 FUNCTION_DECLs. */
22398 {
22401 }
22404 {
22407 }
22409 {
22414 }
22415 }
22417 {
22420 }
22421 else
22424 /* Check for various error cases. Note that if the explicit
22425 instantiation is valid the RESULT will currently be marked as an
22426 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22427 until we get here. */
22430 {
22431 /* DR 259 [temp.spec].
22433 Both an explicit instantiation and a declaration of an explicit
22434 specialization shall not appear in a program unless the explicit
22435 instantiation follows a declaration of the explicit specialization.
22437 For a given set of template parameters, if an explicit
22438 instantiation of a template appears after a declaration of an
22439 explicit specialization for that template, the explicit
22440 instantiation has no effect. */
22442 }
22444 {
22445 /* [temp.spec]
22447 No program shall explicitly instantiate any template more
22448 than once.
22450 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22451 the first instantiation was `extern' and the second is not,
22452 and EXTERN_P for the opposite case. */
22455 /* If an "extern" explicit instantiation follows an ordinary
22456 explicit instantiation, the template is instantiated. */
22459 }
22461 {
22464 }
22466 {
22469 }
22472 ;
22474 {
22477 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22480 }
22481 else
22489 }
22491 static void
22493 {
22499 {
22502 }
22503 }
22505 /* Called from do_type_instantiation through binding_table_foreach to
22506 do recursive instantiation for the type bound in ENTRY. */
22507 static void
22509 {
22515 }
22517 /* Perform an explicit instantiation of template class T. STORAGE, if
22518 non-null, is the RID for extern, inline or static. COMPLAIN is
22519 nonzero if this is called from the parser, zero if called recursively,
22520 since the standard is unclear (as detailed below). */
22522 void
22524 {
22534 {
22535 tree tmpl =
22539 else
22542 }
22547 {
22550 t);
22552 }
22555 {
22557 {
22559 {
22562 "ISO C++ 1998 forbids the use of %<extern%> on "
22564 }
22565 else
22567 "ISO C++ forbids the use of %qE"
22569 }
22577 else
22578 {
22580 storage);
22582 }
22583 }
22586 {
22587 /* DR 259 [temp.spec].
22589 Both an explicit instantiation and a declaration of an explicit
22590 specialization shall not appear in a program unless the explicit
22591 instantiation follows a declaration of the explicit specialization.
22593 For a given set of template parameters, if an explicit
22594 instantiation of a template appears after a declaration of an
22595 explicit specialization for that template, the explicit
22596 instantiation has no effect. */
22598 }
22600 {
22601 /* [temp.spec]
22603 No program shall explicitly instantiate any template more
22604 than once.
22606 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22607 instantiation was `extern'. If EXTERN_P then the second is.
22608 These cases are OK. */
22615 /* If we've already instantiated the template, just return now. */
22618 }
22626 /* In contrast to implicit instantiation, where only the
22627 declarations, and not the definitions, of members are
22628 instantiated, we have here:
22630 [temp.explicit]
22632 The explicit instantiation of a class template specialization
22633 implies the instantiation of all of its members not
22634 previously explicitly specialized in the translation unit
22635 containing the explicit instantiation.
22637 Of course, we can't instantiate member template classes, since we
22638 don't have any arguments for them. Note that the standard is
22639 unclear on whether the instantiation of the members are
22640 *explicit* instantiations or not. However, the most natural
22641 interpretation is that it should be an explicit
22642 instantiation. */
22646 && !static_p
22649 {
22654 }
22659 }
22661 /* Given a function DECL, which is a specialization of TMPL, modify
22662 DECL to be a re-instantiation of TMPL with the same template
22663 arguments. TMPL should be the template into which tsubst'ing
22664 should occur for DECL, not the most general template.
22666 One reason for doing this is a scenario like this:
22668 template <class T>
22669 void f(const T&, int i);
22671 void g() { f(3, 7); }
22673 template <class T>
22674 void f(const T& t, const int i) { }
22676 Note that when the template is first instantiated, with
22677 instantiate_template, the resulting DECL will have no name for the
22678 first parameter, and the wrong type for the second. So, when we go
22679 to instantiate the DECL, we regenerate it. */
22681 static void
22683 {
22684 /* The arguments used to instantiate DECL, from the most general
22685 template. */
22686 tree code_pattern;
22690 /* Make sure that we can see identifiers, and compute access
22691 correctly. */
22695 {
22696 tree decl_parm;
22697 tree pattern_parm;
22698 tree specs;
22712 specs);
22714 /* Merge parameter declarations. */
22717 pattern_parm
22721 {
22722 tree parm_type;
22723 tree attributes;
22728 NULL_TREE);
22734 {
22737 }
22740 }
22741 /* Merge any parameters that match with the function parameter
22742 pack. */
22744 {
22746 tree expanded_types;
22747 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22748 the parameters in this function parameter pack. */
22753 {
22754 tree parm_type;
22755 tree attributes;
22758 /* Rename the parameter to include the index. */
22767 {
22770 }
22772 }
22773 }
22774 /* Merge additional specifiers from the CODE_PATTERN. */
22778 }
22780 {
22790 }
22791 else
22795 }
22797 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22798 substituted to get DECL. */
22800 tree
22802 {
22805 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22806 for the instantiation. This is not always the most general
22807 template. Consider, for example:
22809 template <class T>
22810 struct S { template <class U> void f();
22811 template <> void f<int>(); };
22813 and an instantiation of S<double>::f<int>. We want TD to be the
22814 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22816 more general template. */
22818 /* We must also deal with friend templates. Given:
22820 template <class T> struct S {
22821 template <class U> friend void f() {};
22822 };
22824 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22825 so far as the language is concerned, but that's still
22826 where we get the pattern for the instantiation from. On
22827 other hand, if the definition comes outside the class, say:
22829 template <class T> struct S {
22830 template <class U> friend void f();
22831 };
22832 template <class U> friend void f() {}
22834 we don't need to look any further. That's what the check for
22835 DECL_INITIAL is for. */
22839 {
22840 /* The present template, TD, should not be a definition. If it
22841 were a definition, we should be using it! Note that we
22842 cannot restructure the loop to just keep going until we find
22843 a template with a definition, since that might go too far if
22844 a specialization was declared, but not defined. */
22846 /* Fetch the more general template. */
22848 }
22851 }
22853 /* Returns true if we need to instantiate this template instance even if we
22854 know we aren't going to emit it. */
22856 bool
22858 {
22859 /* We always instantiate inline functions so that we can inline them. An
22860 explicit instantiation declaration prohibits implicit instantiation of
22861 non-inline functions. With high levels of optimization, we would
22862 normally inline non-inline functions -- but we're not allowed to do
22863 that for "extern template" functions. Therefore, we check
22864 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22868 /* And we need to instantiate static data members so that
22869 their initializers are available in integral constant
22870 expressions. */
22873 }
22875 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22876 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22877 error, true otherwise. */
22879 bool
22881 {
22884 /* Don't instantiate a noexcept-specification from template context. */
22899 {
22905 {
22906 /* If hash_set::add returns true, the element was already there. */
22911 fn);
22913 }
22915 {
22930 }
22931 else
22941 }
22944 {
22947 else
22949 }
22952 }
22954 /* We're starting to process the function INST, an instantiation of PATTERN;
22955 add their parameters to local_specializations. */
22957 static void
22959 {
22963 {
22967 }
22969 {
22971 {
22974 }
22975 else
22976 {
22977 /* Register the (value) argument pack as a specialization of
22978 TMPL_PARM, then move on. */
22981 }
22982 }
22984 }
22986 /* Produce the definition of D, a _DECL generated from a template. If
22987 DEFER_OK is true, then we don't have to actually do the
22988 instantiation now; we just have to do it sometime. Normally it is
22989 an error if this is an explicit instantiation but D is undefined.
22990 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22991 instantiated class template. */
22993 tree
22995 {
22997 tree gen_args;
22998 tree args;
22999 tree td;
23000 tree code_pattern;
23001 tree spec;
23002 tree gen_tmpl;
23010 /* This function should only be used to instantiate templates for
23011 functions and static member variables. */
23014 /* A concept is never instantiated. */
23017 /* Variables are never deferred; if instantiation is required, they
23018 are instantiated right away. That allows for better code in the
23019 case that an expression refers to the value of the variable --
23020 if the variable has a constant value the referring expression can
23021 take advantage of that fact. */
23025 /* Don't instantiate cloned functions. Instead, instantiate the
23026 functions they cloned. */
23034 /* D has already been instantiated or explicitly specialized, so
23035 there's nothing for us to do here.
23037 It might seem reasonable to check whether or not D is an explicit
23038 instantiation, and, if so, stop here. But when an explicit
23039 instantiation is deferred until the end of the compilation,
23040 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23041 the instantiation. */
23044 /* Check to see whether we know that this template will be
23045 instantiated in some other file, as with "extern template"
23046 extension. */
23049 /* In general, we do not instantiate such templates. */
23057 /* We should already have the extra args. */
23060 /* And what's in the hash table should match D. */
23064 /* This needs to happen before any tsubsting. */
23070 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23071 for the instantiation. */
23076 {
23077 /* Look up an explicit specialization, if any. */
23081 {
23084 }
23085 }
23089 /* We should never be trying to instantiate a member of a class
23090 template or partial specialization. */
23095 /* In the case of a friend template whose definition is provided
23096 outside the class, we may have too many arguments. Drop the
23097 ones we don't need. The same is true for specializations. */
23098 args = get_innermost_template_args
23102 {
23108 }
23109 else
23110 {
23115 else
23117 }
23119 /* We may be in the middle of deferred access check. Disable it now. */
23122 /* Unless an explicit instantiation directive has already determined
23123 the linkage of D, remember that a definition is available for
23124 this entity. */
23134 /* If D is a member of an explicitly instantiated class template,
23135 and no definition is available, treat it like an implicit
23136 instantiation. */
23139 {
23140 /* Leave linkage flags alone on instantiations with anonymous
23141 visibility. */
23143 {
23146 }
23148 }
23150 /* Defer all other templates, unless we have been explicitly
23151 forbidden from doing so. */
23153 template. */
23154 ! pattern_defined
23155 /* If it's OK to postpone instantiation, do so. */
23156 || defer_ok
23157 /* If this is a static data member that will be defined
23158 elsewhere, we don't want to instantiate the entire data
23159 member, but we do want to instantiate the initializer so that
23160 we can substitute that elsewhere. */
23162 /* Handle here a deleted function too, avoid generating
23163 its body (c++/61080). */
23165 {
23166 /* The definition of the static data member is now required so
23167 we must substitute the initializer. */
23171 {
23172 tree ns;
23173 tree init;
23182 args,
23185 /* If instantiating the initializer involved instantiating this
23186 again, don't call cp_finish_decl twice. */
23188 {
23189 /* Make sure the initializer is still constant, in case of
23190 circular dependency (template/instantiate6.C). */
23191 const_init
23195 LOOKUP_ONLYCONVERTING);
23196 }
23200 }
23202 /* We restore the source position here because it's used by
23203 add_pending_template. */
23209 /* [temp.explicit]
23211 The definition of a non-exported function template, a
23212 non-exported member function template, or a non-exported
23213 member function or static data member of a class template
23214 shall be present in every translation unit in which it is
23215 explicitly instantiated. */
23219 /* If we're in unevaluated context, we just wanted to get the
23220 constant value; this isn't an odr use, so don't queue
23221 a full instantiation. */
23224 /* ??? Historically, we have instantiated inline functions, even
23225 when marked as "extern template". */
23229 }
23230 /* Tell the repository that D is available in this translation unit
23231 -- and see if it is supposed to be instantiated here. */
23233 {
23234 /* In a PCH file, despite the fact that the repository hasn't
23235 requested instantiation in the PCH it is still possible that
23236 an instantiation will be required in a file that includes the
23237 PCH. */
23240 /* Instantiate inline functions so that the inliner can do its
23241 job, even though we'll not be emitting a copy of this
23242 function. */
23245 }
23248 tree fn_context;
23259 else
23260 {
23264 }
23266 /* Mark D as instantiated so that recursive calls to
23267 instantiate_decl do not try to instantiate it again. */
23270 /* Regenerate the declaration in case the template has been modified
23271 by a subsequent redeclaration. */
23274 /* We already set the file and line above. Reset them now in case
23275 they changed as a result of calling regenerate_decl_from_template. */
23279 {
23280 tree init;
23283 /* Clear out DECL_RTL; whatever was there before may not be right
23284 since we've reset the type of the declaration. */
23288 /* The initializer is placed in DECL_INITIAL by
23289 regenerate_decl_from_template so we don't need to
23290 push/pop_access_scope again here. Pull it out so that
23291 cp_finish_decl can process it. */
23296 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23297 initializer. That function will defer actual emission until
23298 we have a chance to determine linkage. */
23301 /* Enter the scope of D so that access-checking works correctly. */
23314 }
23318 {
23319 /* Set up the list of local specializations. */
23323 /* Set up context. */
23327 else
23330 /* Some typedefs referenced from within the template code need to be
23331 access checked at template instantiation time, i.e now. These
23332 types were added to the template at parsing time. Let's get those
23333 and perform the access checks then. */
23335 args);
23337 /* Create substitution entries for the parameters. */
23340 /* Substitute into the body of the function. */
23344 else
23345 {
23350 /* Set the current input_location to the end of the function
23351 so that finish_function knows where we are. */
23352 input_location
23355 /* Remember if we saw an infinite loop in the template. */
23356 current_function_infinite_loop
23358 }
23360 /* Finish the function. */
23364 else
23365 {
23368 }
23372 }
23374 /* We're not deferring instantiation any more. */
23379 else
23385 out:
23394 }
23396 /* Run through the list of templates that we wish we could
23397 instantiate, and instantiate any we can. RETRIES is the
23398 number of times we retry pending template instantiation. */
23400 void
23402 {
23406 /* Instantiating templates may trigger vtable generation. This in turn
23407 may require further template instantiations. We place a limit here
23408 to avoid infinite loop. */
23410 {
23414 "template instantiation depth exceeds maximum of %d"
23415 " instantiating %q+D, possibly from virtual table generation"
23419 /* Pretend that we defined it. */
23422 }
23424 do
23425 {
23430 {
23435 {
23437 {
23452 }
23455 }
23456 else
23457 {
23460 {
23461 instantiation
23467 }
23471 }
23474 /* If INSTANTIATION has been instantiated, then we don't
23475 need to consider it again in the future. */
23477 else
23478 {
23481 }
23484 }
23486 }
23490 }
23492 /* Substitute ARGVEC into T, which is a list of initializers for
23493 either base class or a non-static data member. The TREE_PURPOSEs
23494 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23495 instantiate_decl. */
23497 static tree
23499 {
23503 {
23504 tree decl;
23505 tree init;
23511 {
23512 tree expr;
23513 tree arg;
23515 /* Expand the base class expansion type into separate base
23516 classes. */
23518 tf_warning_or_error,
23519 NULL_TREE);
23523 /* We'll be building separate TREE_LISTs of arguments for
23524 each base. */
23530 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23531 expand each argument in the TREE_VALUE of t. */
23538 /* VOID_TYPE_NODE is used to indicate
23539 value-initialization. */
23540 {
23543 }
23544 else
23545 {
23546 /* Substitute parameter packs into each argument in the
23547 TREE_LIST. */
23550 {
23551 tree expanded_exprs;
23553 /* Expand the argument. */
23555 expanded_exprs
23557 tf_warning_or_error,
23558 NULL_TREE);
23562 /* Prepend each of the expanded expressions to the
23563 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23565 {
23570 }
23571 }
23574 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23575 since we built them backwards. */
23577 {
23580 }
23581 }
23582 }
23585 {
23587 {
23591 }
23592 else
23593 {
23594 tree tmp;
23609 /* If we had an initializer but it instantiated to nothing,
23610 value-initialize the object. This will only occur when
23611 the initializer was a pack expansion where the parameter
23612 packs used in that expansion were of length zero. */
23615 }
23618 {
23622 }
23623 }
23624 }
23626 }
23628 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23630 static void
23632 {
23637 else
23639 }
23641 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23642 is the instantiation (which should have been created with
23643 start_enum) and ARGS are the template arguments to use. */
23645 static void
23647 {
23648 tree e;
23654 {
23655 tree value;
23656 tree decl;
23659 /* Note that in a template enum, the TREE_VALUE is the
23660 CONST_DECL, not the corresponding INTEGER_CST. */
23665 /* Give this enumeration constant the correct access. */
23668 /* Actually build the enumerator itself. Here we're assuming that
23669 enumerators can't have dependent attributes. */
23672 }
23682 }
23684 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23685 its type -- but without substituting the innermost set of template
23686 arguments. So, innermost set of template parameters will appear in
23687 the type. */
23689 tree
23691 {
23692 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23694 }
23696 /* Return truthvalue if we're processing a template different from
23697 the last one involved in diagnostics. */
23698 bool
23700 {
23702 }
23704 /* Remember current template involved in diagnostics. */
23705 void
23707 {
23709 }
23713 {
23715 }
23717 /* Return TRUE if current_function_decl is being instantiated, false
23718 otherwise. */
23720 bool
23722 {
23725 }
23727 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23728 type. Return false for ok, true for disallowed. Issue error and
23729 inform messages under control of COMPLAIN. */
23731 static bool
23733 {
23748 /* A bound template template parm could later be instantiated to have a valid
23749 nontype parm type via an alias template. */
23755 {
23758 else
23760 type);
23761 }
23763 }
23765 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23766 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23768 static bool
23770 {
23771 tree scope;
23773 /* [temp.dep.type]
23775 A type is dependent if it is:
23777 -- a template parameter. Template template parameters are types
23778 for us (since TYPE_P holds true for them) so we handle
23779 them here. */
23783 /* -- a qualified-id with a nested-name-specifier which contains a
23784 class-name that names a dependent type or whose unqualified-id
23785 names a dependent type. */
23789 /* An alias template specialization can be dependent even if the
23790 resulting type is not. */
23794 /* -- a cv-qualified type where the cv-unqualified type is
23795 dependent.
23796 No code is necessary for this bullet; the code below handles
23797 cv-qualified types, and we don't want to strip aliases with
23798 TYPE_MAIN_VARIANT because of DR 1558. */
23799 /* -- a compound type constructed from any dependent type. */
23809 {
23810 tree arg_type;
23815 arg_type;
23820 /* A value-dependent noexcept-specifier makes the type dependent. */
23823 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23824 affect overload resolution and treating it as dependent breaks
23825 things. */
23830 }
23831 /* -- an array type constructed from any dependent type or whose
23832 size is specified by a constant expression that is
23833 value-dependent.
23835 We checked for type- and value-dependence of the bounds in
23836 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23838 {
23843 }
23845 /* -- a template-id in which either the template name is a template
23846 parameter ... */
23849 /* ... or any of the template arguments is a dependent type or
23850 an expression that is type-dependent or value-dependent. */
23852 && (any_dependent_template_arguments_p
23856 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23857 dependent; if the argument of the `typeof' expression is not
23858 type-dependent, then it should already been have resolved. */
23864 /* A template argument pack is dependent if any of its packed
23865 arguments are. */
23867 {
23873 }
23875 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23876 be template parameters. */
23883 /* The standard does not specifically mention types that are local
23884 to template functions or local classes, but they should be
23885 considered dependent too. For example:
23887 template <int I> void f() {
23888 enum E { a = I };
23889 S<sizeof (E)> s;
23890 }
23892 The size of `E' cannot be known until the value of `I' has been
23893 determined. Therefore, `E' must be considered dependent. */
23897 /* Don't use type_dependent_expression_p here, as it can lead
23898 to infinite recursion trying to determine whether a lambda
23899 nested in a lambda is dependent (c++/47687). */
23903 && (any_dependent_template_arguments_p
23907 /* Other types are non-dependent. */
23909 }
23911 /* Returns TRUE if TYPE is dependent, in the sense of
23912 [temp.dep.type]. Note that a NULL type is considered dependent. */
23914 bool
23916 {
23917 /* If there are no template parameters in scope, then there can't be
23918 any dependent types. */
23920 {
23921 /* If we are not processing a template, then nobody should be
23922 providing us with a dependent type. */
23926 }
23928 /* If the type is NULL, we have not computed a type for the entity
23929 in question; in that case, the type is dependent. */
23933 /* Erroneous types can be considered non-dependent. */
23937 /* Getting here with global_type_node means we improperly called this
23938 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23941 /* If we have not already computed the appropriate value for TYPE,
23942 do so now. */
23944 {
23947 }
23950 }
23952 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23953 lookup. In other words, a dependent type that is not the current
23954 instantiation. */
23956 bool
23958 {
23961 }
23963 /* T is a SCOPE_REF; return whether we need to consider it
23964 instantiation-dependent so that we can check access at instantiation
23965 time even though we know which member it resolves to. */
23967 static bool
23969 {
23972 /* A dependent base could make a member inaccessible in the current
23973 class. */
23978 else
23980 }
23982 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23983 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23984 expression. */
23986 /* Note that this predicate is not appropriate for general expressions;
23987 only constant expressions (that satisfy potential_constant_expression)
23988 can be tested for value dependence. */
23990 bool
23992 {
23996 /* A type-dependent expression is also value-dependent. */
24001 {
24003 /* A dependent member function of the current instantiation. */
24007 /* A dependent member function of the current instantiation. */
24014 /* A name that has not been looked up -- must be dependent. */
24018 /* A non-type template parm. */
24022 /* A non-type template parm. */
24028 /* A constant with literal type and is initialized
24029 with an expression that is value-dependent. */
24031 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24035 {
24039 }
24048 /* These expressions are value-dependent if the type to which
24049 the cast occurs is dependent or the expression being casted
24050 is value-dependent. */
24051 {
24057 /* A functional cast has a list of operands. */
24060 {
24061 /* If there are no operands, it must be an expression such
24062 as "int()". This should not happen for aggregate types
24063 because it would form non-constant expressions. */
24068 }
24074 }
24079 /* FALLTHRU */
24082 /* A `sizeof' expression is value-dependent if the operand is
24083 type-dependent or is a pack expansion. */
24092 /* An 'encode' expression is value-dependent if the operand is
24093 type-dependent. */
24102 /* All instantiation-dependent expressions should also be considered
24103 value-dependent. */
24111 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24112 is value-dependent. */
24113 {
24122 }
24125 {
24142 }
24153 {
24157 }
24160 /* Treat all requires-expressions as value-dependent so
24161 we don't try to fold them. */
24168 {
24175 {
24177 /* In a call to a constexpr member function, look through the
24178 implicit ADDR_EXPR on the object argument so that it doesn't
24179 cause the call to be considered value-dependent. We also
24180 look through it in potential_constant_expression. */
24187 }
24189 }
24195 {
24197 tree val;
24204 }
24207 /* Treat a GNU statement expression as dependent to avoid crashing
24208 under instantiate_non_dependent_expr; it can't be constant. */
24212 /* A constant expression is value-dependent if any subexpression is
24213 value-dependent. */
24215 {
24222 {
24226 {
24229 /* In some cases, some of the operands may be missing.
24230 (For example, in the case of PREDECREMENT_EXPR, the
24231 amount to increment by may be missing.) That doesn't
24232 make the expression dependent. */
24235 }
24236 }
24240 }
24242 }
24244 /* The expression is not value-dependent. */
24246 }
24248 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24249 [temp.dep.expr]. Note that an expression with no type is
24250 considered dependent. Other parts of the compiler arrange for an
24251 expression with type-dependent subexpressions to have no type, so
24252 this function doesn't have to be fully recursive. */
24254 bool
24256 {
24265 /* An unresolved name is always dependent. */
24271 /* A fold expression is type-dependent. */
24278 /* Some expression forms are never type-dependent. */
24292 /* The types of these expressions depends only on the type to which
24293 the cast occurs. */
24302 /* The types of these expressions depends only on the type created
24303 by the expression. */
24306 {
24307 /* For NEW_EXPR tree nodes created inside a template, either
24308 the object type itself or a TREE_LIST may appear as the
24309 operand 1. */
24312 /* This is an array type. We need to check array dimensions
24313 as well. */
24315 || value_dependent_expression_p
24317 else
24319 }
24322 {
24326 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24327 contains an identifier associated by name lookup with one or more
24328 declarations declared with a dependent type, or...a
24329 nested-name-specifier or qualified-id that names a member of an
24330 unknown specialization. */
24333 }
24343 {
24344 tree elt;
24348 {
24351 }
24353 }
24355 /* A static data member of the current instantiation with incomplete
24356 array type is type-dependent, as the definition and specializations
24357 can have different bounds. */
24364 /* An array of unknown bound depending on a variadic parameter, eg:
24366 template<typename... Args>
24367 void foo (Args... args)
24368 {
24369 int arr[] = { args... };
24370 }
24372 template<int... vals>
24373 void bar ()
24374 {
24375 int arr[] = { vals... };
24376 }
24378 If the array has no length and has an initializer, it must be that
24379 we couldn't determine its length in cp_complete_array_type because
24380 it is dependent. */
24388 /* A function or variable template-id is type-dependent if it has any
24389 dependent template arguments. */
24393 {
24394 /* Consider the innermost template arguments, since those are the ones
24395 that come from the template-id; the template arguments for the
24396 enclosing class do not make it type-dependent unless they are used in
24397 the type of the decl. */
24399 && (any_dependent_template_arguments_p
24402 }
24404 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24405 type-dependent. Checking this is important for functions with auto return
24406 type, which looks like a dependent type. */
24414 {
24418 }
24420 /* Always dependent, on the number of arguments if nothing else. */
24425 {
24430 {
24436 }
24437 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24442 {
24447 }
24450 {
24457 }
24467 }
24471 /* Dependent type attributes might not have made it from the decl to
24472 the type yet. */
24478 }
24480 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24481 type-dependent if the expression refers to a member of the current
24482 instantiation and the type of the referenced member is dependent, or the
24483 class member access expression refers to a member of an unknown
24484 specialization.
24486 This function returns true if the OBJECT in such a class member access
24487 expression is of an unknown specialization. */
24489 bool
24491 {
24492 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24493 dependent. */
24498 }
24500 /* walk_tree callback function for instantiation_dependent_expression_p,
24501 below. Returns non-zero if a dependent subexpression is found. */
24503 static tree
24506 {
24508 {
24509 /* We don't have to worry about decltype currently because decltype
24510 of an instantiation-dependent expr is a dependent type. This
24511 might change depending on the resolution of DR 1172. */
24514 }
24517 {
24518 /* Don't treat an argument list as dependent just because it has no
24519 TREE_TYPE. */
24527 /* Handle expressions with type operands. */
24532 {
24537 {
24540 else
24541 {
24544 }
24545 }
24547 }
24551 /* In a template, finish_class_member_access_expr creates a
24552 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24553 type-dependent, so that we can check access control at
24554 instantiation time (PR 42277). See also Core issue 1273. */
24561 else
24564 /* Treat statement-expressions as dependent. */
24568 /* Treat requires-expressions as dependent. */
24573 /* Treat calls to function concepts as dependent. */
24579 /* And variable concepts. */
24586 }
24590 else
24592 }
24594 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24595 sense defined by the ABI:
24597 "An expression is instantiation-dependent if it is type-dependent
24598 or value-dependent, or it has a subexpression that is type-dependent
24599 or value-dependent."
24601 Except don't actually check value-dependence for unevaluated expressions,
24602 because in sizeof(i) we don't care about the value of i. Checking
24603 type-dependence will in turn check value-dependence of array bounds/template
24604 arguments as needed. */
24606 bool
24608 {
24609 tree result;
24620 }
24622 /* As above, but also check value-dependence of the expression as a whole. */
24624 bool
24626 {
24629 }
24631 /* Like type_dependent_expression_p, but it also works while not processing
24632 a template definition, i.e. during substitution or mangling. */
24634 bool
24636 {
24642 }
24644 /* Returns TRUE if ARGS contains a type-dependent expression. */
24646 bool
24648 {
24650 tree arg;
24653 {
24656 }
24658 }
24660 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24661 expressions) contains any type-dependent expressions. */
24663 bool
24665 {
24671 }
24673 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24674 expressions) contains any value-dependent expressions. */
24676 bool
24678 {
24684 }
24686 /* Returns TRUE if the ARG (a template argument) is dependent. */
24688 bool
24690 {
24694 /* Assume a template argument that was wrongly written by the user
24695 is dependent. This is consistent with what
24696 any_dependent_template_arguments_p [that calls this function]
24697 does. */
24707 {
24710 /* A member template of a dependent class is not necessarily
24711 type-dependent, but it is a dependent template argument because it
24712 will be a member of an unknown specialization to that template. */
24715 }
24717 {
24721 {
24724 }
24727 }
24730 else
24733 }
24735 /* Returns true if ARGS (a collection of template arguments) contains
24736 any types that require structural equality testing. */
24738 bool
24740 {
24750 {
24753 {
24759 {
24760 /* Look inside the argument pack. */
24763 }
24766 {
24779 }
24780 }
24781 }
24784 }
24786 /* Returns true if ARGS (a collection of template arguments) contains
24787 any dependent arguments. */
24789 bool
24791 {
24801 {
24806 }
24809 }
24811 /* Returns TRUE if the template TMPL is type-dependent. */
24813 bool
24815 {
24817 {
24822 }
24824 /* Template template parameters are dependent. */
24828 /* So are names that have not been looked up. */
24832 }
24834 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24836 bool
24838 {
24841 }
24843 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24844 are dependent. */
24846 bool
24848 {
24855 {
24877 {
24881 }
24885 {
24889 {
24894 }
24895 }
24896 }
24899 }
24901 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24902 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24903 no such TYPE can be found. Note that this function peers inside
24904 uninstantiated templates and therefore should be used only in
24905 extremely limited situations. ONLY_CURRENT_P restricts this
24906 peering to the currently open classes hierarchy (which is required
24907 when comparing types). */
24909 tree
24911 {
24912 tree scope;
24913 tree name;
24914 tree decl;
24916 tree pushed_scope;
24917 tree result;
24922 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24923 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24924 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24925 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24926 identifier of the TYPENAME_TYPE anymore.
24927 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24928 TYPENAME_TYPE instead, we avoid messing up with a possible
24929 typedef variant case. */
24932 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24933 it first before we can figure out what NAME refers to. */
24935 {
24937 /* Given a class template A with a dependent base with nested type C,
24938 typedef typename A::C::C C will land us here, as trying to resolve
24939 the initial A::C leads to the local C typedef, which leads back to
24940 A::C::C. So we break the recursion now. */
24942 else
24944 }
24945 /* If we don't know what SCOPE refers to, then we cannot resolve the
24946 TYPENAME_TYPE. */
24949 /* If this is a typedef, we don't want to look inside (c++/11987). */
24952 /* If SCOPE isn't the template itself, it will not have a valid
24953 TYPE_FIELDS list. */
24955 /* scope is either the template itself or a compatible instantiation
24956 like X<T>, so look up the name in the original template. */
24958 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24960 /* If scope has no fields, it can't be a current instantiation. Check this
24961 before currently_open_class to avoid infinite recursion (71515). */
24964 /* If the SCOPE is not the current instantiation, there's no reason
24965 to look inside it. */
24968 /* Enter the SCOPE so that name lookup will be resolved as if we
24969 were in the class definition. In particular, SCOPE will no
24970 longer be considered a dependent type. */
24972 /* Look up the declaration. */
24974 tf_warning_or_error);
24978 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24979 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24985 {
24989 }
24992 {
24993 /* Obtain the template and the arguments. */
24996 {
24997 /* We get here with a plain identifier because a previous tentative
24998 parse of the nested-name-specifier as part of a ptr-operator saw
24999 ::template X<A>. The use of ::template is necessary in a
25000 ptr-operator, but wrong in a declarator-id.
25002 [temp.names]: In a qualified-id of a declarator-id, the keyword
25003 template shall not appear at the top level. */
25007 }
25009 /* Instantiate the template. */
25015 }
25017 /* Leave the SCOPE. */
25021 /* If we failed to resolve it, return the original typename. */
25025 /* If lookup found a typename type, resolve that too. */
25027 {
25028 /* Ill-formed programs can cause infinite recursion here, so we
25029 must catch that. */
25033 }
25035 /* Qualify the resulting type. */
25041 }
25043 /* EXPR is an expression which is not type-dependent. Return a proxy
25044 for EXPR that can be used to compute the types of larger
25045 expressions containing EXPR. */
25047 tree
25049 {
25051 tree inner_expr;
25053 /* When checking, try to get a constant value for all non-dependent
25054 expressions in order to expose bugs in *_dependent_expression_p
25055 and constexpr. This can affect code generation, see PR70704, so
25056 only do this for -fchecking=2. */
25059 /* Don't do this during nsdmi parsing as it can lead to
25060 unexpected recursive instantiations. */
25062 /* Don't do this during concept expansion either and for
25063 the same reason. */
25069 /* Preserve OVERLOADs; the functions must be available to resolve
25070 types. */
25081 /* There is no need to return a proxy for a variable. */
25084 /* Preserve string constants; conversions from string constants to
25085 "char *" are allowed, even though normally a "const char *"
25086 cannot be used to initialize a "char *". */
25089 /* Preserve void and arithmetic constants, as an optimization -- there is no
25090 reason to create a new node. */
25095 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25096 There is at least one place where we want to know that a
25097 particular expression is a throw-expression: when checking a ?:
25098 expression, there are special rules if the second or third
25099 argument is a throw-expression. */
25103 /* Don't wrap an initializer list, we need to be able to look inside. */
25107 /* Don't wrap a dummy object, we need to be able to test for it. */
25126 /* If the type is unknown, it can't really be non-dependent */
25129 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25131 }
25133 /* ARGS is a vector of expressions as arguments to a function call.
25134 Replace the arguments with equivalent non-dependent expressions.
25135 This modifies ARGS in place. */
25137 void
25139 {
25141 tree arg;
25144 {
25148 }
25149 }
25151 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25152 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25153 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25155 static tree
25157 {
25171 }
25173 tree
25175 {
25177 }
25179 tree
25181 {
25183 }
25185 /* Return a C++17 deduction placeholder for class template TMPL. */
25187 tree
25189 {
25193 }
25195 /* True iff T is a C++17 class template deduction placeholder. */
25197 bool
25199 {
25201 }
25203 /* Make a "constrained auto" type-specifier. This is an
25204 auto type with constraints that must be associated after
25205 deduction. The constraint is formed from the given
25206 CONC and its optional sequence of arguments, which are
25207 non-null if written as partial-concept-id. */
25209 tree
25211 {
25214 /* Build the constraint. */
25222 /* Our canonical type depends on the constraint. */
25225 /* Attach the constraint to the type declaration. */
25228 }
25230 /* Given type ARG, return std::initializer_list<ARG>. */
25232 static tree
25234 {
25238 {
25242 "deducing from brace-enclosed initializer list"
25246 }
25252 }
25254 /* Replace auto in TYPE with std::initializer_list<auto>. */
25256 static tree
25258 {
25265 }
25267 /* Hash traits for hashing possibly constrained 'auto'
25268 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25271 {
25274 };
25276 /* Hash the 'auto' T. */
25278 inline hashval_t
25280 {
25282 /* Matching constrained-type-specifiers denote the same template
25283 parameter, so hash the constraint. */
25285 else
25286 /* But unconstrained autos are all separate, so just hash the pointer. */
25288 }
25290 /* Compare two 'auto's. */
25294 {
25301 /* Two unconstrained autos are distinct. */
25306 }
25308 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25309 constrained) auto, add it to the vector. */
25311 static int
25313 {
25316 {
25317 /* All the autos were built with index 0; fix that up now. */
25321 /* If this is a repeated constrained-type-specifier, use the index we
25322 chose before. */
25324 else
25325 {
25326 /* Otherwise this is new, so use the current count. */
25329 }
25331 }
25333 /* Always keep walking. */
25335 }
25337 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25338 says they can appear anywhere in the type. */
25340 static tree
25342 {
25351 {
25356 }
25359 }
25361 /* The stem for deduction guide names. */
25364 /* Return the name for a deduction guide for class template TMPL. */
25366 tree
25368 {
25379 }
25381 /* True if NAME is the name of a deduction guide. */
25383 bool
25385 {
25389 }
25391 /* True if FN is a deduction guide. */
25393 bool
25395 {
25400 }
25402 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25404 bool
25406 {
25413 }
25415 /* True if FN is a guide generated from a constructor template. */
25417 bool
25419 {
25427 }
25429 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25430 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25431 template parameter types. Note that the handling of template template
25432 parameters relies on current_template_parms being set appropriately for the
25433 new template. */
25435 static tree
25438 {
25441 tree newtype;
25444 {
25451 }
25452 else
25456 tree newdecl
25461 tree newidx;
25464 {
25474 {
25479 // First create a copy (ttargs) of tsubst_args with an
25480 // additional level for the template template parameter's own
25481 // template parameters (ttparms).
25482 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25490 // Substitute ttargs into ttparms to fix references to
25491 // other template parameters.
25493 complain);
25494 // Now substitute again with args based on tparms, to reduce
25495 // the level of the ttparms.
25498 complain);
25499 // Finally, tack the adjusted parms onto tparms.
25501 current_template_parms);
25503 }
25504 }
25505 else
25506 {
25508 tree newconst
25520 }
25523 }
25525 /* Returns a C++17 class deduction guide template based on the constructor
25526 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25527 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25529 static tree
25531 {
25535 location_t loc;
25539 {
25543 {
25546 }
25547 else
25557 }
25558 else
25559 {
25562 fn_tmpl
25572 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25573 fully specialized args for the enclosing class. Strip those off, as
25574 the deduction guide won't have those template parameters. */
25577 /* Discard the 'this' parameter. */
25585 {
25588 /* For a member template constructor, we need to flatten the two
25589 template parameter lists into one, and then adjust the function
25590 signature accordingly. This gets...complicated. */
25593 /* For a member template we should have two levels of parms/args, one
25594 for the class and one for the constructor. We stripped
25595 specialized args for further enclosing classes above. */
25599 /* Template args for translating references to the two-level template
25600 parameters into references to the one-level template parameters we
25601 are creating. */
25606 /* Template parms for the constructor template. */
25609 /* Template parms for the class template. */
25613 /* Template parms for the deduction guide start as a copy of the
25614 template parms for the class. We set current_template_parms for
25615 lookup_template_class_1. */
25621 /* Now we need to rewrite the constructor parms to append them to the
25622 class parms. */
25624 {
25639 }
25641 /* Now we have a final set of template parms to substitute into the
25642 function signature. */
25651 }
25653 }
25656 {
25657 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25661 }
25665 FUNCTION_DECL,
25682 }
25684 /* Deduce template arguments for the class template placeholder PTYPE for
25685 template TMPL based on the initializer INIT, and return the resulting
25686 type. */
25688 static tree
25690 tsubst_flags_t complain)
25691 {
25693 {
25694 /* We should have handled this in the caller. */
25700 }
25711 {
25714 {
25715 /* As an exception, the first phase in 16.3.1.7 (considering the
25716 initializer list as a single argument) is omitted if the
25717 initializer list consists of a single expression of type cv U,
25718 where U is a specialization of C or a class derived from a
25719 specialization of C. */
25730 }
25733 else
25735 }
25736 else
25747 /* Prune explicit deduction guides in copy-initialization context. */
25749 {
25755 {
25756 /* Found a nonconverting guide, prune the candidates. */
25763 }
25764 }
25769 {
25772 }
25775 // FIXME cache artificial deduction guides
25777 {
25782 else
25786 }
25790 /* If this is list-initialization and the class has a list constructor, first
25791 try deducing from the list as a single argument, as [over.match.list]. */
25795 {
25799 }
25801 {
25807 {
25808 /* That didn't work, now try treating the list as a sequence of
25809 arguments. */
25812 }
25813 }
25815 /* Maybe generate an implicit deduction guide. */
25817 {
25821 /* Generate a copy guide. */
25824 /* Generate a default guide. */
25828 {
25831 }
25832 }
25835 {
25837 " of %qT, as it has no non-explicit deduction guides or "
25840 }
25842 {
25846 }
25849 {
25853 }
25856 {
25866 }
25871 }
25873 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25874 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25876 tree
25878 {
25880 tf_warning_or_error,
25881 adc_unspecified);
25882 }
25884 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25885 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25886 The CONTEXT determines the context in which auto deduction is performed
25887 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25888 OUTER_TARGS are used during template argument deduction
25889 (context == adc_unify) to properly substitute the result, and is ignored
25890 in other contexts.
25892 For partial-concept-ids, extra args may be appended to the list of deduced
25893 template arguments prior to determining constraint satisfaction. */
25895 tree
25899 {
25900 tree targs;
25907 /* Defining a subset of type-dependent expressions that we can deduce
25908 from ahead of time isn't worth the trouble. */
25911 /* Similarly, we can't deduce from another undeduced decl. */
25916 /* C++17 class template argument deduction. */
25920 /* Nothing we can do with this, even in deduction context. */
25923 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25924 with either a new invented type template parameter U or, if the
25925 initializer is a braced-init-list (8.5.4), with
25926 std::initializer_list<U>. */
25928 {
25933 else
25934 {
25936 {
25940 "for deduction to %<std::initializer_list%>, use copy-"
25942 }
25944 }
25945 }
25956 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25957 and initializer has array type, deduce cv-qualified array type. */
25959 complain);
25961 {
25970 {
25974 }
25975 }
25976 else
25977 {
25979 tree tparms;
25983 else
25984 {
25988 }
25995 {
25997 /* Try again at instantiation time. */
26001 /* If type is error_mark_node a diagnostic must have been
26002 emitted by now. Also, having a mention to '<type error>'
26003 in the diagnostic is not really useful to the user. */
26004 {
26008 else
26013 }
26015 }
26016 }
26018 /* Check any placeholder constraints against the deduced type. */
26021 {
26022 /* Use the deduced type to check the associated constraints. If we
26023 have a partial-concept-id, rebuild the argument list so that
26024 we check using the extra arguments. */
26028 {
26031 }
26032 else
26035 {
26037 {
26039 {
26057 }
26059 }
26061 }
26062 }
26068 }
26070 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26071 result. */
26073 tree
26075 {
26077 {
26083 /* In an abbreviated function template we didn't know we were dealing
26084 with a function template when we saw the auto return type, so update
26085 it to have the correct level. */
26087 }
26089 }
26091 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26092 'decltype(auto)' or a deduced class template. */
26094 bool
26096 {
26102 else
26104 }
26106 /* for_each_template_parm callback for type_uses_auto. */
26108 int
26110 {
26112 }
26114 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26115 a use of `auto'. Returns NULL_TREE otherwise. */
26117 tree
26119 {
26123 {
26124 /* The Concepts TS allows multiple autos in one type-specifier; just
26125 return the first one we find, do_auto_deduction will collect all of
26126 them. */
26130 else
26132 }
26133 else
26135 }
26137 /* For a given template T, return the vector of typedefs referenced
26138 in T for which access check is needed at T instantiation time.
26139 T is either a FUNCTION_DECL or a RECORD_TYPE.
26140 Those typedefs were added to T by the function
26141 append_type_to_template_for_access_check. */
26145 {
26146 tree ti;
26157 {
26162 }
26165 }
26167 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26168 tied to T. That list of typedefs will be access checked at
26169 T instantiation time.
26170 T is either a FUNCTION_DECL or a RECORD_TYPE.
26171 TYPE_DECL is a TYPE_DECL node representing a typedef.
26172 SCOPE is the scope through which TYPE_DECL is accessed.
26173 LOCATION is the location of the usage point of TYPE_DECL.
26175 This function is a subroutine of
26176 append_type_to_template_for_access_check. */
26178 static void
26180 tree type_decl,
26181 tree scope,
26182 location_t location)
26183 {
26184 qualified_typedef_usage_t typedef_usage;
26185 tree ti;
26192 && type_decl
26206 }
26208 /* Append TYPE_DECL to the template TEMPL.
26209 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26210 At TEMPL instanciation time, TYPE_DECL will be checked to see
26211 if it can be accessed through SCOPE.
26212 LOCATION is the location of the usage point of TYPE_DECL.
26214 e.g. consider the following code snippet:
26216 class C
26217 {
26218 typedef int myint;
26219 };
26221 template<class U> struct S
26222 {
26223 C::myint mi; // <-- usage point of the typedef C::myint
26224 };
26226 S<char> s;
26228 At S<char> instantiation time, we need to check the access of C::myint
26229 In other words, we need to check the access of the myint typedef through
26230 the C scope. For that purpose, this function will add the myint typedef
26231 and the scope C through which its being accessed to a list of typedefs
26232 tied to the template S. That list will be walked at template instantiation
26233 time and access check performed on each typedefs it contains.
26234 Note that this particular code snippet should yield an error because
26235 myint is private to C. */
26237 void
26239 tree type_decl,
26240 tree scope,
26241 location_t location)
26242 {
26248 /* Make sure we don't append the type to the template twice. */
26255 }
26257 /* Convert the generic type parameters in PARM that match the types given in the
26258 range [START_IDX, END_IDX) from the current_template_parms into generic type
26259 packs. */
26261 tree
26263 {
26274 {
26275 /* Create a distinct parameter pack type from the current parm and add it
26276 to the replacement args to tsubst below into the generic function
26277 parameter. */
26292 }
26298 /* If there are more levels then build up the replacement with the outer
26299 template parms. */
26303 replacement);
26306 }
26308 /* Entries in the decl_constraint hash table. */
26310 {
26311 tree decl;
26312 tree ci;
26313 };
26315 /* Hashing function and equality for constraint entries. */
26317 {
26319 {
26321 }
26324 {
26326 }
26327 };
26329 /* A mapping from declarations to constraint information. Note that
26330 both templates and their underlying declarations are mapped to the
26331 same constraint information.
26333 FIXME: This is defined in pt.c because garbage collection
26334 code is not being generated for constraint.cc. */
26338 /* Returns the template constraints of declaration T. If T is not
26339 constrained, return NULL_TREE. Note that T must be non-null. */
26341 tree
26343 {
26354 else
26356 }
26358 /* Associate the given constraint information CI with the declaration
26359 T. If T is a template, then the constraints are associated with
26360 its underlying declaration. Don't build associations if CI is
26361 NULL_TREE. */
26363 void
26365 {
26377 }
26379 /* Remove the associated constraints of the declaration T. */
26381 void
26383 {
26392 }
26394 /* Memoized satisfaction results for declarations. This
26395 maps the pair (constraint_info, arguments) to the result computed
26396 by constraints_satisfied_p. */
26399 {
26400 tree ci;
26401 tree args;
26402 tree result;
26403 };
26405 /* Hashing function and equality for constraint entries. */
26408 {
26410 {
26413 }
26416 {
26418 }
26419 };
26421 /* Memoized satisfaction results for concept checks. */
26424 {
26425 tree tmpl;
26426 tree args;
26427 tree result;
26428 };
26430 /* Hashing function and equality for constraint entries. */
26433 {
26435 {
26437 }
26440 {
26445 }
26446 };
26451 /* Search for a memoized satisfaction result. Returns one of the
26452 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26454 tree
26456 {
26461 else
26463 }
26465 /* Memoize the result of a satisfication test. Returns the saved result. */
26467 tree
26469 {
26476 }
26478 /* Search for a memoized satisfaction result for a concept. */
26480 tree
26482 {
26487 else
26489 }
26491 /* Memoize the result of a concept check. Returns the saved result. */
26493 tree
26495 {
26502 }
26506 /* Returns a prior concept specialization. This returns the substituted
26507 and normalized constraints defined by the concept. */
26509 tree
26511 {
26516 else
26518 }
26520 /* Save a concept expansion for later. */
26522 tree
26524 {
26531 }
26533 static hashval_t
26535 {
26544 }
26546 /* Compare the constraints of two subsumption entries. The LEFT1 and
26547 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26548 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26550 static bool
26552 {
26560 }
26562 /* Key/value pair for learning and memoizing subsumption results. This
26563 associates a pair of check constraints (including arguments) with
26564 a boolean value indicating the result. */
26567 {
26568 tree t1;
26569 tree t2;
26571 };
26573 /* Hashing function and equality for constraint entries. */
26576 {
26578 {
26580 }
26583 {
26588 }
26589 };
26593 /* Search for a previously cached subsumption result. */
26597 {
26602 else
26604 }
26606 /* Save a subsumption result. */
26608 bool
26610 {
26617 }
26619 /* Set up the hash table for constraint association. */
26621 void
26623 {
26632 }
26634 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26635 0..N-1. */
26637 void
26639 {
26642 integer_type_node,
26643 NULL_TREE),
26647 }
26649 /* Set up the hash tables for template instantiations. */
26651 void
26653 {
26659 }
26661 /* Print stats about the template hash tables for -fstats. */
26663 void
26665 {
26674 }
26676 #if CHECKING_P
26680 /* Verify that build_non_dependent_expr () works, for various expressions,
26681 and that location wrappers don't affect the results. */
26683 static void
26685 {
26688 /* Verify constants, without and with location wrappers. */
26705 }
26707 /* Verify that type_dependent_expression_p () works correctly, even
26708 in the presence of location wrapper nodes. */
26710 static void
26712 {
26717 /* If no templates are involved, nothing is type-dependent. */
26723 /* Within a template, an unresolved name is always type-dependent. */
26726 /* Ensure it copes with NULL_TREE and errors. */
26730 /* A USING_DECL in a template should be type-dependent, even if wrapped
26731 with a location wrapper (PR c++/83799). */
26740 }
26742 /* Run all of the selftests within this file. */
26744 void
26746 {
26749 }