| blob | 07dad99650462cd774739ecfb5d143316a53f0c6 |
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 {
1140 {
1149 /* Allow typedefs on the type of a non-type argument, since a
1151 else
1153 }
1154 }
1156 static void
1158 {
1163 }
1165 /* Retrieve the specialization (in the sense of [temp.spec] - a
1166 specialization is either an instantiation or an explicit
1167 specialization) of TMPL for the given template ARGS. If there is
1168 no such specialization, return NULL_TREE. The ARGS are a vector of
1169 arguments, or a vector of vectors of arguments, in the case of
1170 templates with more than one level of parameters.
1172 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1173 then we search for a partial specialization matching ARGS. This
1174 parameter is ignored if TMPL is not a class template.
1176 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1177 result is a NONTYPE_ARGUMENT_PACK. */
1179 static tree
1181 {
1191 /* There should be as many levels of arguments as there are
1192 levels of parameters. */
1201 /* Lambda functions in templates aren't instantiated normally, but through
1202 tsubst_lambda_expr. */
1207 {
1208 /* The template arguments actually apply to the containing
1209 class. Find the class specialization with those
1210 arguments. */
1212 tree class_specialization
1217 /* Find the instance of TMPL. */
1220 {
1223 /* using-declarations can add base methods to the method vec,
1224 and we don't want those here. */
1227 }
1229 }
1230 else
1231 {
1233 spec_entry elt;
1242 else
1250 }
1253 }
1255 /* Like retrieve_specialization, but for local declarations. */
1257 tree
1259 {
1265 }
1267 /* Returns nonzero iff DECL is a specialization of TMPL. */
1269 int
1271 {
1272 tree t;
1275 {
1281 }
1282 else
1283 {
1292 }
1295 }
1297 /* Returns nonzero iff DECL is a specialization of friend declaration
1298 FRIEND_DECL according to [temp.friend]. */
1300 bool
1302 {
1309 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1310 of a template class, we want to check if DECL is a specialization
1311 if this. */
1315 {
1316 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1319 }
1324 /* There is nothing to do if this is not a template friend. */
1331 /* [temp.friend/6]
1332 A member of a class template may be declared to be a friend of a
1333 non-template class. In this case, the corresponding member of
1334 every specialization of the class template is a friend of the
1335 class granting friendship.
1337 For example, given a template friend declaration
1339 template <class T> friend void A<T>::f();
1341 the member function below is considered a friend
1343 template <> struct A<int> {
1344 void f();
1345 };
1347 For this type of template friend, TEMPLATE_DEPTH below will be
1348 nonzero. To determine if DECL is a friend of FRIEND, we first
1349 check if the enclosing class is a specialization of another. */
1356 {
1357 /* Next, we check the members themselves. In order to handle
1358 a few tricky cases, such as when FRIEND_DECL's are
1360 template <class T> friend void A<T>::g(T t);
1361 template <class T> template <T t> friend void A<T>::h();
1363 and DECL's are
1365 void A<int>::g(int);
1366 template <int> void A<int>::h();
1368 we need to figure out ARGS, the template arguments from
1369 the context of DECL. This is required for template substitution
1370 of `T' in the function parameter of `g' and template parameter
1371 of `h' in the above examples. Here ARGS corresponds to `int'. */
1378 {
1380 {
1383 else
1385 current_depth++;
1386 }
1388 }
1391 {
1393 tree friend_type;
1394 tree decl_type;
1395 tree friend_args_type;
1396 tree decl_args_type;
1398 /* Make sure that both DECL and FRIEND_DECL are templates or
1399 non-templates. */
1405 {
1406 /* If both are templates, check template parameter list. */
1407 tree friend_parms
1412 friend_parms))
1416 }
1417 else
1425 /* Check if return types match. */
1429 /* Check if function parameter types match, ignoring the
1430 `this' parameter. */
1439 }
1440 else
1441 {
1442 /* DECL is a TYPE_DECL */
1446 /* Make sure that both DECL and FRIEND_DECL are templates or
1447 non-templates. */
1448 is_template
1455 {
1456 tree friend_parms;
1457 /* If both are templates, check the name of the two
1458 TEMPLATE_DECL's first because is_friend didn't. */
1463 /* Now check template parameter list. */
1464 friend_parms
1467 return comp_template_parms
1469 friend_parms);
1470 }
1471 else
1474 }
1475 }
1477 }
1479 /* Register the specialization SPEC as a specialization of TMPL with
1480 the indicated ARGS. IS_FRIEND indicates whether the specialization
1481 is actually just a friend declaration. ATTRLIST is the list of
1482 attributes that the specialization is declared with or NULL when
1483 it isn't. Returns SPEC, or an equivalent prior declaration, if
1484 available.
1486 We also store instantiations of field packs in the hash table, even
1487 though they are not themselves templates, to make lookup easier. */
1489 static tree
1491 hashval_t hash)
1492 {
1493 tree fn;
1495 spec_entry elt;
1503 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1504 register it; we want the corresponding TEMPLATE_DECL instead.
1505 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1506 the more obvious `uses_template_parms (spec)' to avoid problems
1507 with default function arguments. In particular, given
1508 something like this:
1510 template <class T> void f(T t1, T t = T())
1512 the default argument expression is not substituted for in an
1513 instantiation unless and until it is actually needed. */
1517 /* We don't put these specializations in the hash table, but we might
1518 want to give an error about a mismatch. */
1520 else
1521 {
1529 slot =
1533 else
1535 }
1537 /* We can sometimes try to re-register a specialization that we've
1538 already got. In particular, regenerate_decl_from_template calls
1539 duplicate_decls which will update the specialization list. But,
1540 we'll still get called again here anyhow. It's more convenient
1541 to simply allow this than to try to prevent it. */
1545 {
1547 {
1550 {
1552 fn);
1554 }
1555 else
1556 {
1557 tree clone;
1558 /* This situation should occur only if the first
1559 specialization is an implicit instantiation, the
1560 second is an explicit specialization, and the
1561 implicit instantiation has not yet been used. That
1562 situation can occur if we have implicitly
1563 instantiated a member function and then specialized
1564 it later.
1566 We can also wind up here if a friend declaration that
1567 looked like an instantiation turns out to be a
1568 specialization:
1570 template <class T> void foo(T);
1571 class S { friend void foo<>(int) };
1572 template <> void foo(int);
1574 We transform the existing DECL in place so that any
1575 pointers to it become pointers to the updated
1576 declaration.
1578 If there was a definition for the template, but not
1579 for the specialization, we want this to look as if
1580 there were no definition, and vice versa. */
1583 /* The call to duplicate_decls will have applied
1584 [temp.expl.spec]:
1586 An explicit specialization of a function template
1587 is inline only if it is explicitly declared to be,
1588 and independently of whether its function template
1589 is.
1591 to the primary function; now copy the inline bits to
1592 the various clones. */
1594 {
1601 }
1605 }
1606 }
1608 {
1611 /* We've already complained in duplicate_decls. */
1615 /* Dup decl failed, but this is a new definition. Set the
1616 line number so any errors match this new
1617 definition. */
1621 }
1622 }
1626 /* A specialization must be declared in the same namespace as the
1627 template it is specializing. */
1633 {
1642 /* If TMPL is a forward declaration of a template function, keep a list
1643 of all specializations in case we need to reassign them to a friend
1644 template later in tsubst_friend_function.
1646 Also keep a list of all variable template instantiations so that
1647 process_partial_specialization can check whether a later partial
1648 specialization would have used it. */
1651 }
1654 }
1656 /* Returns true iff two spec_entry nodes are equivalent. */
1660 bool
1662 {
1669 /* tmpl could be a FIELD_DECL for a capture pack. */
1673 {
1674 /* Partial specializations of a variable template can be distinguished by
1675 constraints. */
1679 }
1683 }
1685 /* Returns a hash for a template TMPL and template arguments ARGS. */
1687 static hashval_t
1689 {
1692 }
1694 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1695 ignoring SPEC. */
1697 hashval_t
1699 {
1701 }
1703 /* Recursively calculate a hash value for a template argument ARG, for use
1704 in the hash tables of template specializations. */
1706 hashval_t
1708 {
1728 {
1736 {
1741 }
1763 {
1767 {
1770 }
1772 }
1776 {
1779 }
1790 val = iterative_hash_template_arg
1802 val);
1804 val);
1813 /* A lambda can't appear in a template arg, but don't crash on
1814 erroneous input. */
1826 /* Now hash operands as usual. */
1831 }
1834 {
1837 {
1838 // We want an alias specialization that survived strip_typedefs
1839 // to hash differently from its TYPE_CANONICAL, to avoid hash
1840 // collisions that compare as different in template_args_equal.
1841 // These could be dependent specializations that strip_typedefs
1842 // left alone, or untouched specializations because
1843 // coerce_template_parms returns the unconverted template
1844 // arguments if it sees incomplete argument packs.
1847 }
1850 val);
1853 /* Otherwise just compare the types during lookup. */
1862 {
1867 }
1868 }
1871 }
1873 /* Unregister the specialization SPEC as a specialization of TMPL.
1874 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1875 if the SPEC was listed as a specialization of TMPL.
1877 Note that SPEC has been ggc_freed, so we can't look inside it. */
1879 bool
1881 {
1883 spec_entry elt;
1891 {
1896 }
1899 }
1901 /* Like register_specialization, but for local declarations. We are
1902 registering SPEC, an instantiation of TMPL. */
1904 void
1906 {
1909 }
1911 /* TYPE is a class type. Returns true if TYPE is an explicitly
1912 specialized class. */
1914 bool
1916 {
1920 }
1922 /* Print the list of functions at FNS, going through all the overloads
1923 for each element of the list. Alternatively, FNS can not be a
1924 TREE_LIST, in which case it will be printed together with all the
1925 overloads.
1927 MORE and *STR should respectively be FALSE and NULL when the function
1928 is called from the outside. They are used internally on recursive
1929 calls. print_candidates manages the two parameters and leaves NULL
1930 in *STR when it ends. */
1932 static void
1934 {
1938 else
1940 {
1946 {
1949 else
1952 }
1954 }
1955 }
1957 /* Print the list of candidate FNS in an error message. FNS can also
1958 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1960 void
1962 {
1966 }
1968 /* Get a (possibly) constrained template declaration for the
1969 purpose of ordering candidates. */
1970 static tree
1972 {
1978 }
1980 /* Among candidates having the same signature, return the
1981 most constrained or NULL_TREE if there is no best candidate.
1982 If the signatures of candidates vary (e.g., template
1983 specialization vs. member function), then there can be no
1984 most constrained.
1986 Note that we don't compare constraints on the functions
1987 themselves, but rather those of their templates. */
1988 static tree
1990 {
1991 // Try to find the best candidate in a first pass.
1994 {
2001 }
2003 // Verify that the champ is better than previous candidates.
2008 }
2011 }
2014 /* Returns the template (one of the functions given by TEMPLATE_ID)
2015 which can be specialized to match the indicated DECL with the
2016 explicit template args given in TEMPLATE_ID. The DECL may be
2017 NULL_TREE if none is available. In that case, the functions in
2018 TEMPLATE_ID are non-members.
2020 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2021 specialization of a member template.
2023 The TEMPLATE_COUNT is the number of references to qualifying
2024 template classes that appeared in the name of the function. See
2025 check_explicit_specialization for a more accurate description.
2027 TSK indicates what kind of template declaration (if any) is being
2028 declared. TSK_TEMPLATE indicates that the declaration given by
2029 DECL, though a FUNCTION_DECL, has template parameters, and is
2030 therefore a template function.
2032 The template args (those explicitly specified and those deduced)
2033 are output in a newly created vector *TARGS_OUT.
2035 If it is impossible to determine the result, an error message is
2036 issued. The error_mark_node is returned to indicate failure. */
2038 static tree
2040 tree decl,
2044 tmpl_spec_kind tsk)
2045 {
2046 tree fns;
2047 tree targs;
2048 tree explicit_targs;
2051 /* A TREE_LIST of templates of which DECL may be a specialization.
2052 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2053 corresponding TREE_PURPOSE is the set of template arguments that,
2054 when used to instantiate the template, would produce a function
2055 with the signature of DECL. */
2065 /* We shouldn't be specializing a member template of an
2066 unspecialized class template; we already gave an error in
2067 check_specialization_scope, now avoid crashing. */
2071 {
2074 }
2082 /* Check for baselinks. */
2087 {
2090 }
2092 {
2095 }
2097 /* Count the number of template headers specified for this
2098 specialization. */
2108 {
2111 tf_warning_or_error,
2115 }
2117 {
2121 {
2122 tree decl_arg_types;
2123 tree fn_arg_types;
2124 tree insttype;
2126 /* In case of explicit specialization, we need to check if
2127 the number of template headers appearing in the specialization
2128 is correct. This is usually done in check_explicit_specialization,
2129 but the check done there cannot be exhaustive when specializing
2130 member functions. Consider the following code:
2132 template <> void A<int>::f(int);
2133 template <> template <> void A<int>::f(int);
2135 Assuming that A<int> is not itself an explicit specialization
2136 already, the first line specializes "f" which is a non-template
2137 member function, whilst the second line specializes "f" which
2138 is a template member function. So both lines are syntactically
2139 correct, and check_explicit_specialization does not reject
2140 them.
2142 Here, we can do better, as we are matching the specialization
2143 against the declarations. We count the number of template
2144 headers, and we check if they match TEMPLATE_COUNT + 1
2145 (TEMPLATE_COUNT is the number of qualifying template classes,
2146 plus there must be another header for the member template
2147 itself).
2149 Notice that if header_count is zero, this is not a
2150 specialization but rather a template instantiation, so there
2151 is no check we can perform here. */
2155 /* Check that the number of template arguments at the
2156 innermost level for DECL is the same as for FN. */
2164 /* DECL might be a specialization of FN. */
2168 /* For a non-static member function, we need to make sure
2169 that the const qualification is the same. Since
2170 get_bindings does not try to merge the "this" parameter,
2171 we must do the comparison explicitly. */
2173 {
2178 /* And the ref-qualification. */
2182 }
2184 /* Skip the "this" parameter and, for constructors of
2185 classes with virtual bases, the VTT parameter. A
2186 full specialization of a constructor will have a VTT
2187 parameter, but a template never will. */
2188 decl_arg_types
2190 fn_arg_types
2193 /* Function templates cannot be specializations; there are
2194 no partial specializations of functions. Therefore, if
2195 the type of DECL does not match FN, there is no
2196 match.
2198 Note that it should never be the case that we have both
2199 candidates added here, and for regular member functions
2200 below. */
2202 {
2206 }
2208 /* See whether this function might be a specialization of this
2209 template. Suppress access control because we might be trying
2210 to make this specialization a friend, and we have already done
2211 access control for the declaration of the specialization. */
2217 /* We cannot deduce template arguments that when used to
2218 specialize TMPL will produce DECL. */
2222 /* We deduced something involving 'auto', which isn't a valid
2223 template argument. */
2226 /* Remove, from the set of candidates, all those functions
2227 whose constraints are not satisfied. */
2231 // Then, try to form the new function type.
2235 fn_arg_types
2240 /* Save this template, and the arguments deduced. */
2242 }
2244 /* FN is an ordinary member function, and we need a
2245 specialization of a member template. */
2246 ;
2248 /* We can get IDENTIFIER_NODEs here in certain erroneous
2249 cases. */
2250 ;
2252 /* This is just an ordinary non-member function. Nothing can
2253 be a specialization of that. */
2254 ;
2256 /* Cannot specialize functions that are created implicitly. */
2257 ;
2258 else
2259 {
2260 tree decl_arg_types;
2262 /* This is an ordinary member function. However, since
2263 we're here, we can assume its enclosing class is a
2264 template class. For example,
2266 template <typename T> struct S { void f(); };
2267 template <> void S<int>::f() {}
2269 Here, S<int>::f is a non-template, but S<int> is a
2270 template class. If FN has the same type as DECL, we
2271 might be in business. */
2274 /* Its enclosing class is an explicit specialization
2275 of a template class. This is not a candidate. */
2280 /* The return types differ. */
2283 /* Adjust the type of DECL in case FN is a static member. */
2290 decl_arg_types))
2298 // If the deduced arguments do not satisfy the constraints,
2299 // this is not a candidate.
2303 // Add the candidate.
2305 }
2306 }
2309 {
2310 /* We have:
2312 [temp.expl.spec]
2314 It is possible for a specialization with a given function
2315 signature to be instantiated from more than one function
2316 template. In such cases, explicit specification of the
2317 template arguments must be used to uniquely identify the
2318 function template specialization being specialized.
2320 Note that here, there's no suggestion that we're supposed to
2321 determine which of the candidate templates is most
2322 specialized. However, we, also have:
2324 [temp.func.order]
2326 Partial ordering of overloaded function template
2327 declarations is used in the following contexts to select
2328 the function template to which a function template
2329 specialization refers:
2331 -- when an explicit specialization refers to a function
2332 template.
2334 So, we do use the partial ordering rules, at least for now.
2335 This extension can only serve to make invalid programs valid,
2336 so it's safe. And, there is strong anecdotal evidence that
2337 the committee intended the partial ordering rules to apply;
2338 the EDG front end has that behavior, and John Spicer claims
2339 that the committee simply forgot to delete the wording in
2340 [temp.expl.spec]. */
2343 {
2346 }
2347 }
2349 // Concepts allows multiple declarations of member functions
2350 // with the same signature. Like above, we need to rely on
2351 // on the partial ordering of those candidates to determine which
2352 // is the best.
2354 {
2356 {
2359 }
2360 }
2363 {
2370 else
2373 }
2377 {
2383 }
2385 /* We have one, and exactly one, match. */
2387 {
2391 // Propagate the candidate's constraints to the declaration.
2394 /* DECL is a re-declaration or partial instantiation of a template
2395 function. */
2398 /* It was a specialization of an ordinary member function in a
2399 template class. */
2401 }
2403 /* It was a specialization of a template. */
2406 {
2411 }
2412 else
2415 }
2417 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2418 but with the default argument values filled in from those in the
2419 TMPL_TYPES. */
2421 static tree
2423 tree tmpl_types)
2424 {
2425 tree new_spec_types;
2433 /* Substitute into the rest of the list. */
2434 new_spec_types =
2438 /* Add the default argument for this parameter. */
2441 new_spec_types);
2442 }
2444 /* DECL is an explicit specialization. Replicate default arguments
2445 from the template it specializes. (That way, code like:
2447 template <class T> void f(T = 3);
2448 template <> void f(double);
2449 void g () { f (); }
2451 works, as required.) An alternative approach would be to look up
2452 the correct default arguments at the call-site, but this approach
2453 is consistent with how implicit instantiations are handled. */
2455 static void
2457 {
2458 tree tmpl;
2459 tree spec_types;
2460 tree tmpl_types;
2461 tree new_spec_types;
2462 tree old_type;
2463 tree new_type;
2464 tree t;
2469 /* See if there's anything we need to do. */
2482 {
2483 /* Remove the this pointer, but remember the object's type for
2484 CV quals. */
2490 {
2491 /* DECL may contain more parameters than TMPL due to the extra
2492 in-charge parameter in constructors and destructors. */
2495 }
2497 {
2500 }
2501 }
2503 /* Compute the merged default arguments. */
2504 new_spec_types =
2507 /* Compute the new FUNCTION_TYPE. */
2509 {
2513 new_spec_types);
2516 /* Put the in-charge parameter back. */
2519 new_spec_types);
2523 new_spec_types);
2524 }
2525 else
2527 new_spec_types);
2537 }
2539 /* Return the number of template headers we expect to see for a definition
2540 or specialization of CTYPE or one of its non-template members. */
2542 int
2544 {
2548 {
2549 /* You're supposed to have one `template <...>' for every
2550 template class, but you don't need one for a full
2551 specialization. For example:
2553 template <class T> struct S{};
2554 template <> struct S<int> { void f(); };
2555 void S<int>::f () {}
2557 is correct; there shouldn't be a `template <>' for the
2558 definition of `S<int>::f'. */
2560 /* If CTYPE does not have template information of any
2561 kind, then it is not a template, nor is it nested
2562 within a template. */
2570 }
2573 }
2575 /* Do a simple sanity check on the template headers that precede the
2576 variable declaration DECL. */
2578 void
2580 {
2585 {
2588 "variable templates only available with "
2591 // Namespace-scope variable templates should have a template header.
2593 }
2595 {
2597 "too many template headers for %qD "
2603 "members of an explicitly specialized class are defined "
2605 }
2606 }
2608 /* An explicit specialization whose declarator-id or class-head-name is not
2609 qualified shall be declared in the nearest enclosing namespace of the
2610 template, or, if the namespace is inline (7.3.1), any namespace from its
2611 enclosing namespace set.
2613 If the name declared in the explicit instantiation is an unqualified name,
2614 the explicit instantiation shall appear in the namespace where its template
2615 is declared or, if that namespace is inline (7.3.1), any namespace from its
2616 enclosing namespace set. */
2618 void
2620 {
2625 {
2631 /* This was allowed in C++98, so only pedwarn. */
2633 "outside its namespace must use a nested-name-"
2635 }
2636 }
2638 /* Warn for a template specialization SPEC that is missing some of a set
2639 of function or type attributes that the template TEMPL is declared with.
2640 ATTRLIST is a list of additional attributes that SPEC should be taken
2641 to ultimately be declared with. */
2643 static void
2645 {
2652 /* Avoid warning if either declaration or its type is deprecated. */
2674 /* Avoid warning if the primary has no attributes. */
2678 /* Avoid warning if either declaration contains an attribute on
2679 the white list below. */
2682 };
2690 /* Avoid warning if the difference between the primary and
2691 the specialization is not in one of the attributes below. */
2695 };
2697 /* Put together a list of the black listed attributes that the primary
2698 template is declared with that the specialization is not, in case
2699 it's not apparent from the most recent declaration of the primary. */
2701 pretty_printer str;
2704 {
2706 {
2711 {
2721 }
2722 }
2723 }
2730 spec))
2736 }
2738 /* Check to see if the function just declared, as indicated in
2739 DECLARATOR, and in DECL, is a specialization of a function
2740 template. We may also discover that the declaration is an explicit
2741 instantiation at this point.
2743 Returns DECL, or an equivalent declaration that should be used
2744 instead if all goes well. Issues an error message if something is
2745 amiss. Returns error_mark_node if the error is not easily
2746 recoverable.
2748 FLAGS is a bitmask consisting of the following flags:
2750 2: The function has a definition.
2751 4: The function is a friend.
2753 The TEMPLATE_COUNT is the number of references to qualifying
2754 template classes that appeared in the name of the function. For
2755 example, in
2757 template <class T> struct S { void f(); };
2758 void S<int>::f();
2760 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2761 classes are not counted in the TEMPLATE_COUNT, so that in
2763 template <class T> struct S {};
2764 template <> struct S<int> { void f(); }
2765 template <> void S<int>::f();
2767 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2768 invalid; there should be no template <>.)
2770 If the function is a specialization, it is marked as such via
2771 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2772 is set up correctly, and it is added to the list of specializations
2773 for that template. */
2775 tree
2777 tree decl,
2780 tree attrlist)
2781 {
2790 tmpl_spec_kind tsk;
2793 {
2796 else
2798 }
2799 else
2803 {
2806 {
2809 }
2811 {
2813 /* This could be something like:
2815 template <class T> void f(T);
2816 class S { friend void f<>(int); } */
2818 else
2819 {
2820 /* This case handles bogus declarations like template <>
2821 template <class T> void f<int>(); */
2824 declarator);
2826 }
2827 }
2831 /* The error has already been reported in
2832 check_specialization_scope. */
2838 /* Fall through. */
2851 decl);
2854 else
2858 /* Fall through. */
2864 /* In cases like template<> constexpr bool v = true;
2865 We'll give an error in check_template_variable. */
2871 else
2877 {
2878 /* This case handles bogus declarations like template <>
2879 template <class T> void f<int>(); */
2883 declarator);
2885 {
2886 /* Partial specialization of variable template. */
2890 }
2894 else
2898 ok:;
2899 }
2902 /* This is a specialization of a member template, without
2903 specialization the containing class. Something like:
2905 template <class T> struct S {
2906 template <class U> void f (U);
2907 };
2908 template <> template <class U> void S<int>::f(U) {}
2910 That's a specialization -- but of the entire template. */
2916 }
2919 /* This doesn't apply to variable templates. */
2922 {
2926 {
2930 }
2931 }
2934 {
2939 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2941 {
2942 tree fns;
2947 else
2948 {
2949 /* If there is no class context, the explicit instantiation
2950 must be at namespace scope. */
2953 /* Find the namespace binding, using the declaration
2954 context. */
2958 /* If lookup fails, look for a friend declaration so we can
2959 give a better diagnostic. */
2965 {
2968 }
2969 }
2972 }
2978 {
2980 /* A specialization in class scope. This is invalid,
2981 but the error will already have been flagged by
2982 check_specialization_scope. */
2984 else
2985 {
2986 /* It's not valid to write an explicit instantiation in
2987 class scope, e.g.:
2989 class C { template void f(); }
2991 This case is caught by the parser. However, on
2992 something like:
2994 template class C { void f(); };
2996 (which is invalid) we can get here. The error will be
2997 issued later. */
2998 ;
2999 }
3002 }
3005 {
3006 // We'll match variable templates in start_decl.
3010 /* Find the list of functions in ctype that have the same
3011 name as the declared function. */
3015 {
3019 {
3020 /* From [temp.expl.spec]:
3022 If such an explicit specialization for the member
3023 of a class template names an implicitly-declared
3024 special member function (clause _special_), the
3025 program is ill-formed.
3027 Similar language is found in [temp.explicit]. */
3030 }
3033 }
3035 /* For a type-conversion operator, We might be looking for
3036 `operator int' which will be a specialization of
3037 `operator T'. Grab all the conversion operators, and
3038 then select from them. */
3043 {
3046 }
3047 else
3049 }
3051 /* Figure out what exactly is being specialized at this point.
3052 Note that for an explicit instantiation, even one for a
3053 member function, we cannot tell a priori whether the
3054 instantiation is for a member template, or just a member
3055 function of a template class. Even if a member template is
3056 being instantiated, the member template arguments may be
3057 elided if they can be deduced from the rest of the
3058 declaration. */
3061 member_specialization,
3062 template_count,
3063 tsk);
3066 /* We couldn't figure out what this declaration was
3067 specializing. */
3069 else
3070 {
3073 {
3075 "friend declaration %qD is not visible to "
3079 }
3087 {
3088 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3089 is done by do_decl_instantiation later. */
3095 {
3096 /* If TMPL is not the most general template (for
3097 example, if TMPL is a friend template that is
3098 injected into namespace scope), then there will
3099 be too many levels of TARGS. Remove some of them
3100 here. */
3102 tree new_targs;
3109 }
3112 }
3114 /* If we thought that the DECL was a member function, but it
3115 turns out to be specializing a static member function,
3116 make DECL a static member function as well. */
3122 /* If this is a specialization of a member template of a
3123 template class, we want to return the TEMPLATE_DECL, not
3124 the specialization of it. */
3126 {
3131 {
3132 tree parm;
3136 /* We want to use the argument list specified in the
3137 definition, not in the original declaration. */
3142 }
3145 }
3147 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3153 /* Inherit default function arguments from the template
3154 DECL is specializing. */
3158 /* This specialization has the same protection as the
3159 template it specializes. */
3163 /* 7.1.1-1 [dcl.stc]
3165 A storage-class-specifier shall not be specified in an
3166 explicit specialization...
3168 The parser rejects these, so unless action is taken here,
3169 explicit function specializations will always appear with
3170 global linkage.
3172 The action recommended by the C++ CWG in response to C++
3173 defect report 605 is to make the storage class and linkage
3174 of the explicit specialization match the templated function:
3176 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3177 */
3179 {
3183 /* A concept cannot be specialized. */
3185 {
3187 gen_tmpl);
3189 }
3191 /* This specialization has the same linkage and visibility as
3192 the function template it specializes. */
3195 {
3198 }
3201 {
3204 }
3205 }
3207 /* If DECL is a friend declaration, declared using an
3208 unqualified name, the namespace associated with DECL may
3209 have been set incorrectly. For example, in:
3211 template <typename T> void f(T);
3212 namespace N {
3213 struct S { friend void f<int>(int); }
3214 }
3216 we will have set the DECL_CONTEXT for the friend
3217 declaration to N, rather than to the global namespace. */
3222 /* This is not really a declaration of a specialization.
3223 It's just the name of an instantiation. But, it's not
3224 a request for an instantiation, either. */
3227 /* A specialization is not necessarily COMDAT. */
3233 /* If this is a full specialization, register it so that we can find
3234 it again. Partial specializations will be registered in
3235 process_partial_specialization. */
3237 {
3242 }
3245 /* A 'structor should already have clones. */
3251 }
3252 }
3255 }
3257 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3258 parameters. These are represented in the same format used for
3259 DECL_TEMPLATE_PARMS. */
3261 int
3263 {
3264 const_tree p1;
3265 const_tree p2;
3273 {
3285 {
3289 /* If either of the template parameters are invalid, assume
3290 they match for the sake of error recovery. */
3303 }
3304 }
3307 /* One set of parameters has more parameters lists than the
3308 other. */
3312 }
3314 /* Determine whether PARM is a parameter pack. */
3316 bool
3318 {
3319 /* Determine if we have a non-type template parameter pack. */
3326 /* If this is a list of template parameters, we could get a
3327 TYPE_DECL or a TEMPLATE_DECL. */
3331 /* Otherwise it must be a type template parameter. */
3335 }
3337 /* Determine if T is a function parameter pack. */
3339 bool
3341 {
3345 }
3347 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3348 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3350 tree
3352 {
3359 }
3361 /* Return true iff the function parameter PARAM_DECL was expanded
3362 from the function parameter pack PACK. */
3364 bool
3366 {
3371 /* The parameter pack and its pack arguments have the same
3372 DECL_PARM_INDEX. */
3374 }
3376 /* Determine whether ARGS describes a variadic template args list,
3377 i.e., one that is terminated by a template argument pack. */
3379 static bool
3381 {
3383 tree last_parm;
3397 }
3399 /* Generate a new name for the parameter pack name NAME (an
3400 IDENTIFIER_NODE) that incorporates its */
3402 static tree
3404 {
3405 /* Munge the name to include the parameter index. */
3406 #define NUMBUF_LEN 128
3420 }
3422 /* Return true if T is a primary function, class or alias template
3423 specialization, not including the template pattern. */
3425 bool
3427 {
3443 }
3445 /* Return true if PARM is a template template parameter. */
3447 bool
3449 {
3451 }
3453 /* Return true iff PARM is a DECL representing a type template
3454 parameter. */
3456 bool
3458 {
3463 }
3465 /* Return the template parameters of T if T is a
3466 primary template instantiation, NULL otherwise. */
3468 tree
3470 {
3475 parms = INNERMOST_TEMPLATE_PARMS
3479 }
3481 /* Return the template parameters of the LEVELth level from the full list
3482 of template parameters PARMS. */
3484 tree
3486 {
3487 tree p;
3498 }
3500 /* Returns the template arguments of T if T is a template instantiation,
3501 NULL otherwise. */
3503 tree
3505 {
3513 }
3515 /* Return the argument pack elements of T if T is a template argument pack,
3516 NULL otherwise. */
3518 tree
3520 {
3526 }
3528 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3529 ARGUMENT_PACK_SELECT represents. */
3531 static tree
3533 {
3537 /* If the selected argument is an expansion E, that most likely means we were
3538 called from gen_elem_of_pack_expansion_instantiation during the
3539 substituting of an argument pack (of which the Ith element is a pack
3540 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3541 In this case, the Ith element resulting from this substituting is going to
3542 be a pack expansion, which pattern is the pattern of E. Let's return the
3543 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3544 resulting pack expansion from it. */
3546 {
3547 /* Make sure we aren't throwing away arg info. */
3550 }
3553 }
3556 /* True iff FN is a function representing a built-in variadic parameter
3557 pack. */
3559 bool
3561 {
3571 }
3573 /* True iff CALL is a call to a function representing a built-in variadic
3574 parameter pack. */
3576 static bool
3578 {
3582 }
3584 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3586 static tree
3588 tree in_decl)
3589 {
3595 {
3597 {
3600 }
3605 }
3606 else
3607 {
3611 /* Calculate the largest value of len that won't make the size of the vec
3612 overflow an int. The compiler will exceed resource limits long before
3613 this, but it seems a decent place to diagnose. */
3617 {
3622 }
3630 }
3631 }
3633 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3634 CALL. */
3636 static tree
3638 tree in_decl)
3639 {
3649 }
3651 /* Structure used to track the progress of find_parameter_packs_r. */
3652 struct find_parameter_pack_data
3653 {
3654 /* TREE_LIST that will contain all of the parameter packs found by
3655 the traversal. */
3658 /* Set of AST nodes that have been visited by the traversal. */
3661 /* True iff we're making a type pack expansion. */
3663 };
3665 /* Identifies all of the argument packs that occur in a template
3666 argument and appends them to the TREE_LIST inside DATA, which is a
3667 find_parameter_pack_data structure. This is a subroutine of
3668 make_pack_expansion and uses_parameter_packs. */
3669 static tree
3671 {
3677 /* Handle type aliases/typedefs. */
3679 {
3686 }
3688 /* Identify whether this is a parameter pack or not. */
3690 {
3698 /* FALLTHRU */
3700 /* If the placeholder appears in the decl-specifier-seq of a function
3701 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3702 is a pack expansion, the invented template parameter is a template
3703 parameter pack. */
3713 {
3714 /* We don't want to walk into the type of a PARM_DECL,
3715 because we don't want to see the type parameter pack. */
3718 }
3723 {
3724 /* We don't want to walk into the type of a variadic capture proxy,
3725 because we don't want to see the type parameter pack. */
3728 }
3730 {
3732 find_parameter_packs_r,
3735 }
3747 /* Not a parameter pack. */
3749 }
3752 {
3753 /* Add this parameter pack to the list. */
3755 }
3761 /* This switch statement will return immediately if we don't find a
3762 parameter pack. */
3764 {
3769 /* Check the template itself. */
3772 /* Check the template arguments. */
3786 /* Ignore the declaration of a capture proxy for a parameter pack. */
3794 /* Fall through. */
3839 {
3840 /* Look at explicit captures. */
3845 /* Since we defer implicit capture, look in the body as well. */
3851 }
3854 {
3855 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3856 type_pack_expansion_p to false so that any placeholders
3857 within the expression don't get marked as parameter packs. */
3865 }
3869 }
3872 }
3874 /* Determines if the expression or type T uses any parameter packs. */
3875 bool
3877 {
3886 }
3888 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3889 representation a base-class initializer into a parameter pack
3890 expansion. If all goes well, the resulting node will be an
3891 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3892 respectively. */
3893 tree
3895 {
3896 tree result;
3905 {
3906 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3907 class initializer. In this case, the TREE_PURPOSE will be a
3908 _TYPE node (representing the base class expansion we're
3909 initializing) and the TREE_VALUE will be a TREE_LIST
3910 containing the initialization arguments.
3912 The resulting expansion looks somewhat different from most
3913 expansions. Rather than returning just one _EXPANSION, we
3914 return a TREE_LIST whose TREE_PURPOSE is a
3915 TYPE_PACK_EXPANSION containing the bases that will be
3916 initialized. The TREE_VALUE will be identical to the
3917 original TREE_VALUE, which is a list of arguments that will
3918 be passed to each base. We do not introduce any new pack
3919 expansion nodes into the TREE_VALUE (although it is possible
3920 that some already exist), because the TREE_PURPOSE and
3921 TREE_VALUE all need to be expanded together with the same
3922 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3923 resulting TREE_PURPOSE will mention the parameter packs in
3924 both the bases and the arguments to the bases. */
3925 tree purpose;
3926 tree value;
3929 /* Determine which parameter packs will be used by the base
3930 class expansion. */
3939 {
3942 arg);
3945 }
3948 {
3949 /* Collect the sets of parameter packs used in each of the
3950 initialization arguments. */
3952 {
3953 /* Determine which parameter packs will be expanded in this
3954 argument. */
3957 }
3958 }
3962 /* Create the pack expansion type for the base type. */
3968 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3969 they will rarely be compared to anything. */
3973 }
3978 /* Build the PACK_EXPANSION_* node. */
3979 result = for_types
3984 {
3985 /* Propagate type and const-expression information. */
3988 /* Mark this read now, since the expansion might be length 0. */
3990 }
3991 else
3992 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3993 they will rarely be compared to anything. */
3996 /* Determine which parameter packs will be expanded. */
4003 /* Make sure we found some parameter packs. */
4005 {
4007 {
4010 else
4012 }
4014 }
4020 }
4022 /* Checks T for any "bare" parameter packs, which have not yet been
4023 expanded, and issues an error if any are found. This operation can
4024 only be done on full expressions or types (e.g., an expression
4025 statement, "if" condition, etc.), because we could have expressions like:
4027 foo(f(g(h(args)))...)
4029 where "args" is a parameter pack. check_for_bare_parameter_packs
4030 should not be called for the subexpressions args, h(args),
4031 g(h(args)), or f(g(h(args))), because we would produce erroneous
4032 error messages.
4034 Returns TRUE and emits an error if there were bare parameter packs,
4035 returns FALSE otherwise. */
4036 bool
4038 {
4045 /* A lambda might use a parameter pack from the containing context. */
4060 {
4064 {
4075 else
4080 else
4084 }
4087 }
4090 }
4092 /* Expand any parameter packs that occur in the template arguments in
4093 ARGS. */
4094 tree
4096 {
4105 /* First, determine if we need to expand anything, and the number of
4106 slots we'll need. */
4108 {
4113 {
4117 else
4119 }
4120 else
4121 {
4123 num_result_args++;
4124 }
4125 }
4127 /* If no expansion is necessary, we're done. */
4131 /* Expand arguments. */
4134 non_default_args_count =
4137 {
4140 {
4147 }
4148 else
4149 {
4152 }
4153 }
4157 }
4159 /* Checks if DECL shadows a template parameter.
4161 [temp.local]: A template-parameter shall not be redeclared within its
4162 scope (including nested scopes).
4164 Emits an error and returns TRUE if the DECL shadows a parameter,
4165 returns FALSE otherwise. */
4167 bool
4169 {
4170 tree olddecl;
4172 /* If we're not in a template, we can't possibly shadow a template
4173 parameter. */
4177 /* Figure out what we're shadowing. */
4181 /* If there's no previous binding for this name, we're not shadowing
4182 anything, let alone a template parameter. */
4186 /* If we're not shadowing a template parameter, we're done. Note
4187 that OLDDECL might be an OVERLOAD (or perhaps even an
4188 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4189 node. */
4193 /* We check for decl != olddecl to avoid bogus errors for using a
4194 name inside a class. We check TPFI to avoid duplicate errors for
4195 inline member templates. */
4201 /* Don't complain about the injected class name, as we've already
4202 complained about the class itself. */
4209 else
4214 }
4216 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4217 ORIG_LEVEL, DECL, and TYPE. */
4219 static tree
4223 tree decl,
4224 tree type)
4225 {
4236 }
4238 /* Find the canonical type parameter for the given template type
4239 parameter. Returns the canonical type parameter, which may be TYPE
4240 if no such parameter existed. */
4242 static tree
4244 {
4245 tree list;
4259 else
4260 {
4264 }
4265 }
4267 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4268 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4269 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4270 new one is created. */
4272 static tree
4274 tsubst_flags_t complain)
4275 {
4280 {
4299 /* Template template parameters need this. */
4301 {
4308 }
4309 }
4312 }
4314 /* Process information from new template parameter PARM and append it
4315 to the LIST being built. This new parameter is a non-type
4316 parameter iff IS_NON_TYPE is true. This new parameter is a
4317 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4318 is in PARM_LOC. */
4320 tree
4323 {
4332 {
4336 {
4340 else
4342 }
4345 }
4348 {
4354 {
4355 /* [temp.param]
4357 The top-level cv-qualifiers on the template-parameter are
4358 ignored when determining its type. */
4363 && !is_parameter_pack
4364 /* If we're in a nested template parameter list, the template
4365 template parameter could be a parameter pack. */
4367 {
4368 /* This template parameter is not a parameter pack, but it
4369 should be. Complain about "bare" parameter packs. */
4372 /* Recover by calling this a parameter pack. */
4374 }
4375 }
4377 /* A template parameter is not modifiable. */
4386 processing_template_decl,
4391 }
4392 else
4393 {
4394 tree t;
4398 {
4400 /* This is for distinguishing between real templates and template
4401 template parameters */
4405 }
4406 else
4407 {
4409 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4412 }
4419 processing_template_decl,
4423 }
4427 /* Build requirements for the type/template parameter.
4428 This must be done after SET_DECL_TEMPLATE_PARM_P or
4429 process_template_parm could fail. */
4437 /* Build the parameter node linking the parameter declaration,
4438 its default argument (if any), and its constraints (if any). */
4443 }
4445 /* The end of a template parameter list has been reached. Process the
4446 tree list into a parameter vector, converting each parameter into a more
4447 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4448 as PARM_DECLs. */
4450 tree
4452 {
4457 /* Pop the dummy parameter level and add the real one. */
4460 current_template_parms
4465 {
4469 }
4474 }
4476 // Explicitly indicate the end of the template parameter list. We assume
4477 // that the current template parameters have been constructed and/or
4478 // managed explicitly, as when creating new template template parameters
4479 // from a shorthand constraint.
4480 void
4482 {
4484 }
4486 /* end_template_decl is called after a template declaration is seen. */
4488 void
4490 {
4496 /* This matches the pushlevel in begin_template_parm_list. */
4501 }
4503 /* Takes a TREE_LIST representing a template parameter and convert it
4504 into an argument suitable to be passed to the type substitution
4505 functions. Note that If the TREE_LIST contains an error_mark
4506 node, the returned argument is error_mark_node. */
4508 tree
4510 {
4523 {
4527 {
4528 /* Turn this argument into a TYPE_ARGUMENT_PACK
4529 with a single element, which expands T. */
4538 }
4539 }
4540 else
4541 {
4545 {
4546 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4547 with a single element, which expands T. */
4557 }
4558 else
4560 }
4562 }
4564 /* Given a single level of template parameters (a TREE_VEC), return it
4565 as a set of template arguments. */
4567 static tree
4569 {
4579 }
4581 /* Given a set of template parameters, return them as a set of template
4582 arguments. The template parameters are represented as a TREE_VEC, in
4583 the form documented in cp-tree.h for template arguments. */
4585 static tree
4587 {
4588 tree header;
4593 /* If there is only one level of template parameters, we do not
4594 create a TREE_VEC of TREE_VECs. Instead, we return a single
4595 TREE_VEC containing the arguments. */
4600 {
4605 else
4607 }
4610 }
4612 /* Within the declaration of a template, return the currently active
4613 template parameters as an argument TREE_VEC. */
4615 static tree
4617 {
4619 }
4621 /* Update the declared TYPE by doing any lookups which were thought to be
4622 dependent, but are not now that we know the SCOPE of the declarator. */
4624 tree
4626 {
4637 /* Don't bother building up the args in this case. */
4639 {
4640 /* tsubst in the args corresponding to the template parameters,
4641 including auto if present. Most things will be unchanged, but
4642 make_typename_type and tsubst_qualified_id will resolve
4643 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4646 tree pushed;
4648 {
4652 }
4657 }
4663 {
4666 else
4668 }
4670 }
4672 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4673 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4674 the new template is a member template. */
4676 tree
4678 {
4687 }
4689 struct template_parm_data
4690 {
4691 /* The level of the template parameters we are currently
4692 processing. */
4695 /* The index of the specialization argument we are currently
4696 processing. */
4699 /* An array whose size is the number of template parameters. The
4700 elements are nonzero if the parameter has been used in any one
4701 of the arguments processed so far. */
4704 /* An array whose size is the number of template arguments. The
4705 elements are nonzero if the argument makes use of template
4706 parameters of this level. */
4708 };
4710 /* Subroutine of push_template_decl used to see if each template
4711 parameter in a partial specialization is used in the explicit
4712 argument list. If T is of the LEVEL given in DATA (which is
4713 treated as a template_parm_data*), then DATA->PARMS is marked
4714 appropriately. */
4716 static int
4718 {
4726 {
4729 }
4731 /* In C++17 the type of a non-type argument is a deduced context. */
4736 data,
4737 NULL,
4740 /* Return zero so that for_each_template_parm will continue the
4741 traversal of the tree; we want to mark *every* template parm. */
4743 }
4745 /* Process the partial specialization DECL. */
4747 static tree
4749 {
4756 tree inner_parms;
4757 tree inst;
4767 /* A concept cannot be specialized. */
4769 {
4772 }
4777 /* We check that each of the template parameters given in the
4778 partial specialization is used in the argument list to the
4779 specialization. For example:
4781 template <class T> struct S;
4782 template <class T> struct S<T*>;
4784 The second declaration is OK because `T*' uses the template
4785 parameter T, whereas
4787 template <class T> struct S<int>;
4789 is no good. Even trickier is:
4791 template <class T>
4792 struct S1
4793 {
4794 template <class U>
4795 struct S2;
4796 template <class U>
4797 struct S2<T>;
4798 };
4800 The S2<T> declaration is actually invalid; it is a
4801 full-specialization. Of course,
4803 template <class U>
4804 struct S2<T (*)(U)>;
4806 or some such would have been OK. */
4814 {
4819 NULL,
4821 }
4824 {
4825 /* One of the template parms was not used in a deduced context in the
4826 specialization. */
4828 {
4832 }
4836 }
4841 /* [temp.class.spec]
4843 The argument list of the specialization shall not be identical to
4844 the implicit argument list of the primary template. */
4845 tree main_args
4848 && (!flag_concepts
4851 {
4854 "any template arguments; to define the primary template, "
4856 else
4858 "template arguments and is not more constrained than "
4859 "the primary template; to define the primary template, "
4862 }
4864 /* A partial specialization that replaces multiple parameters of the
4865 primary template with a pack expansion is less specialized for those
4866 parameters. */
4868 {
4870 "primary template because it replaces multiple parameters "
4873 /* Avoid crash in process_partial_specialization. */
4875 }
4877 /* If we aren't in a dependent class, we can actually try deduction. */
4879 /* FIXME we should be able to handle a partial specialization of a
4880 partial instantiation, but currently we can't (c++/41727). */
4883 {
4887 maintmpl);
4888 }
4890 /* [temp.class.spec]
4892 A partially specialized non-type argument expression shall not
4893 involve template parameters of the partial specialization except
4894 when the argument expression is a simple identifier.
4896 The type of a template parameter corresponding to a specialized
4897 non-type argument shall not be dependent on a parameter of the
4898 specialization.
4900 Also, we verify that pack expansions only occur at the
4901 end of the argument list. */
4905 {
4912 {
4913 /* Extract the arguments from the argument pack. We'll be
4914 iterating over these in the following loop. */
4917 }
4920 {
4922 /* Get the Jth argument in the parameter pack. */
4926 {
4927 /* Pack expansions must come at the end of the
4928 argument list. */
4931 {
4935 else
4938 }
4939 }
4942 /* We only care about the pattern. */
4948 /* This next two lines are the `argument expression is not just a
4949 simple identifier' condition and also the `specialized
4950 non-type argument' bit. */
4954 {
4958 arg);
4959 else
4960 {
4961 /* Look at the corresponding template parameter,
4962 marking which template parameters its type depends
4963 upon. */
4967 {
4968 /* We haven't yet initialized TPD2. Do so now. */
4970 /* The number of parameters here is the number in the
4971 main template, which, as checked in the assertion
4972 above, is NARGS. */
4976 }
4978 /* Mark the template parameters. But this time, we're
4979 looking for the template parameters of the main
4980 template, not in the specialization. */
4987 NULL,
4991 {
4992 /* The type depended on some template parameters.
4993 If they are fully specialized in the
4994 specialization, that's OK. */
5003 "type %qT of template argument %qE depends "
5005 "type %qT of template argument %qE depends "
5007 type,
5008 arg);
5009 }
5010 }
5011 }
5012 }
5013 }
5015 /* We should only get here once. */
5019 // Build the template decl.
5028 /* Give template template parms a DECL_CONTEXT of the template
5029 for which they are a parameter. */
5031 {
5035 }
5038 /* We didn't register this in check_explicit_specialization so we could
5039 wait until the constraints were set. */
5041 else
5051 {
5057 {
5065 "declaration of %qD ambiguates earlier template "
5069 "partial specialization of %qD after instantiation "
5071 }
5072 }
5075 }
5077 /* PARM is a template parameter of some form; return the corresponding
5078 TEMPLATE_PARM_INDEX. */
5080 static tree
5082 {
5095 }
5097 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5098 parameter packs used by the template parameter PARM. */
5100 static void
5102 {
5103 /* A type parm can't refer to another parm. */
5107 {
5111 }
5118 }
5120 /* PARM is a template parameter pack. Return any parameter packs used in
5121 its type or the type of any of its template parameters. If there are
5122 any such packs, it will be instantiated into a fixed template parameter
5123 list by partial instantiation rather than be fully deduced. */
5125 tree
5127 {
5128 /* This can only be true in a member template. */
5131 /* This can only be true for a parameter pack. */
5134 /* A type parm can't refer to another parm. */
5148 }
5150 /* Check that a template declaration's use of default arguments and
5151 parameter packs is not invalid. Here, PARMS are the template
5152 parameters. IS_PRIMARY is true if DECL is the thing declared by
5153 a primary template. IS_PARTIAL is true if DECL is a partial
5154 specialization.
5156 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5157 function template declaration or a friend class template
5158 declaration. In the function case, 1 indicates a declaration, 2
5159 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5160 emitted for extraneous default arguments.
5162 Returns TRUE if there were no errors found, FALSE otherwise. */
5164 bool
5167 {
5170 tree parm_level;
5173 /* [temp.param]
5175 A default template-argument shall not be specified in a
5176 function template declaration or a function template definition, nor
5177 in the template-parameter-list of the definition of a member of a
5178 class template. */
5182 /* You can't have a function template declaration in a local
5183 scope, nor you can you define a member of a class template in a
5184 local scope. */
5192 /* A lambda doesn't have an explicit declaration; don't complain
5193 about the parms of the enclosing class. */
5200 /* If this is either a friend defined in the scope of the class
5201 or a member function. */
5207 /* And, if it was a member function, it really was defined in
5208 the scope of the class. */
5211 /* We already checked these parameters when the template was
5212 declared, so there's no need to do it again now. This function
5213 was defined in class scope, but we're processing its body now
5214 that the class is complete. */
5217 /* Core issue 226 (C++0x only): the following only applies to class
5218 templates. */
5221 {
5222 /* [temp.param]
5224 If a template-parameter has a default template-argument, all
5225 subsequent template-parameters shall have a default
5226 template-argument supplied. */
5228 {
5235 {
5245 {
5247 /* For better subsequent error-recovery, we indicate that
5248 there should have been a default argument. */
5251 }
5253 && !is_friend_decl
5254 /* Don't complain about an enclosing partial
5255 specialization. */
5260 /* A fixed parameter pack will be partially
5261 instantiated into a fixed length list. */
5263 {
5264 /* A primary class template can only have one
5265 parameter pack, at the end of the template
5266 parameter list. */
5274 }
5275 }
5276 }
5277 }
5280 || is_partial
5281 || !is_primary
5283 /* For an ordinary class template, default template arguments are
5284 allowed at the innermost level, e.g.:
5285 template <class T = int>
5286 struct S {};
5287 but, in a partial specialization, they're not allowed even
5288 there, as we have in [temp.class.spec]:
5290 The template parameter list of a specialization shall not
5291 contain default template argument values.
5293 So, for a partial specialization, or for a function template
5294 (in C++98/C++03), we look at all of them. */
5295 ;
5296 else
5297 /* But, for a primary class template that is not a partial
5298 specialization we look at all template parameters except the
5299 innermost ones. */
5302 /* Figure out what error message to issue. */
5317 else
5318 /* Per [temp.param]/9, "A default template-argument shall not be
5319 specified in the template-parameter-lists of the definition of
5320 a member of a class template that appears outside of the member's
5321 class.", thus if we aren't handling a member of a class template
5322 there is no need to examine the parameters. */
5326 /* If we're inside a class definition, there's no need to
5327 examine the parameters to the class itself. On the one
5328 hand, they will be checked when the class is defined, and,
5329 on the other, default arguments are valid in things like:
5330 template <class T = double>
5331 struct S { template <class U> void f(U); };
5332 Here the default argument for `S' has no bearing on the
5333 declaration of `f'. */
5335 else
5336 /* Check everything. */
5342 {
5349 {
5354 {
5356 {
5363 }
5365 /* Clear out the default argument so that we are not
5366 confused later. */
5368 }
5369 }
5371 /* At this point, if we're still interested in issuing messages,
5372 they must apply to classes surrounding the object declared. */
5376 }
5379 }
5381 /* Worker for push_template_decl_real, called via
5382 for_each_template_parm. DATA is really an int, indicating the
5383 level of the parameters we are interested in. If T is a template
5384 parameter of that level, return nonzero. */
5386 static int
5388 {
5394 else
5397 }
5399 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5400 DATA is really an int, indicating the innermost outer level of parameters.
5401 If T is a template parameter of that level or further out, return
5402 nonzero. */
5404 static int
5406 {
5412 else
5415 }
5417 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5418 parameters given by current_template_args, or reuses a
5419 previously existing one, if appropriate. Returns the DECL, or an
5420 equivalent one, if it is replaced via a call to duplicate_decls.
5422 If IS_FRIEND is true, DECL is a friend declaration. */
5424 tree
5426 {
5427 tree tmpl;
5428 tree args;
5429 tree info;
5430 tree ctx;
5434 /* True if the template is a member template, in the sense of
5435 [temp.mem]. */
5441 /* See if this is a partial specialization. */
5454 /* For a friend, we want the context of the friend, not
5455 the type of which it is a friend. */
5459 /* In the case of a virtual function, we want the class in which
5460 it is defined. */
5462 else
5463 /* Otherwise, if we're currently defining some class, the DECL
5464 is assumed to be a member of the class. */
5473 /* See if this is a primary template. */
5476 /* A friend template that specifies a class context, i.e.
5477 template <typename T> friend void A<T>::f();
5478 is not primary. */
5483 else
5487 {
5494 {
5497 }
5499 {
5501 {
5504 }
5506 {
5507 /* [temp.mem]
5509 A destructor shall not be a member template. */
5512 }
5519 {
5520 /* [basic.stc.dynamic.allocation]
5522 An allocation function can be a function
5523 template. ... Template allocation functions shall
5524 have two or more parameters. */
5527 }
5528 }
5531 {
5532 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5535 {
5541 }
5542 }
5545 /* alias-declaration */
5549 else
5550 {
5553 }
5554 }
5556 /* Check to see that the rules regarding the use of default
5557 arguments are not being violated. We check args for a friend
5558 functions when we know whether it's a definition, introducing
5559 declaration or re-declaration. */
5564 /* Ensure that there are no parameter packs in the type of this
5565 declaration that have not been expanded. */
5567 {
5568 /* Check each of the arguments individually to see if there are
5569 any bare parameter packs. */
5575 {
5578 {
5579 /* This is a PARM_DECL that contains unexpanded parameter
5580 packs. We have already complained about this in the
5581 check_for_bare_parameter_packs call, so just replace
5582 these types with ERROR_MARK_NODE. */
5585 }
5589 }
5591 /* Check for bare parameter packs in the return type and the
5592 exception specifiers. */
5594 /* Errors were already issued, set return type to int
5595 as the frontend doesn't expect error_mark_node as
5596 the return type. */
5600 }
5605 {
5608 }
5621 {
5626 /* If DECL is a TYPE_DECL for a class-template, then there won't
5627 be DECL_LANG_SPECIFIC. The information equivalent to
5628 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5632 {
5633 /* Since a template declaration already existed for this
5634 class-type, we must be redeclaring it here. Make sure
5635 that the redeclaration is valid. */
5637 current_template_parms,
5639 /* We don't need to create a new TEMPLATE_DECL; just use the
5640 one we already had. */
5642 }
5643 else
5644 {
5646 member_template_p);
5651 {
5652 /* A specialization of a member template of a template
5653 class. */
5657 }
5658 }
5659 }
5660 else
5661 {
5667 {
5670 }
5678 {
5679 tree new_tmpl;
5681 /* The declaration is a specialization of a member
5682 template, declared outside the class. Therefore, the
5683 innermost template arguments will be NULL, so we
5684 replace them with the arguments determined by the
5685 earlier call to check_explicit_specialization. */
5688 new_tmpl
5690 member_template_p);
5700 args,
5703 }
5705 /* Make sure the template headers we got make sense. */
5710 {
5715 }
5716 else
5718 {
5723 {
5727 else
5731 /* Avoid crash in import_export_decl. */
5734 }
5739 /* Can happen in erroneous input. */
5741 else
5743 }
5745 /* Check that the parms are used in the appropriate qualifying scopes
5746 in the declarator. */
5750 {
5756 /* Avoid crash in import_export_decl. */
5759 }
5760 }
5765 /* Push template declarations for global functions and types. Note
5766 that we do not try to push a global template friend declared in a
5767 template class; such a thing may well depend on the template
5768 parameters of the class. */
5771 {
5776 /* Hide template friend classes that haven't been declared yet. */
5778 {
5781 }
5782 }
5785 {
5790 /* Give template template parms a DECL_CONTEXT of the template
5791 for which they are a parameter. */
5794 {
5798 }
5804 }
5806 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5807 back to its most general template. If TMPL is a specialization,
5808 ARGS may only have the innermost set of arguments. Add the missing
5809 argument levels if necessary. */
5817 else
5818 {
5823 }
5826 && !is_friend
5829 /* Set DECL_COMDAT on template instantiations; if we force
5830 them to be emitted by explicit instantiation or -frepo,
5831 mark_needed will tell cgraph to do the right thing. */
5835 }
5837 tree
5839 {
5841 }
5843 /* FN is an inheriting constructor that inherits from the constructor
5844 template INHERITED; turn FN into a constructor template with a matching
5845 template header. */
5847 tree
5849 {
5850 tree inner_parms
5853 tree parms
5864 }
5866 /* Called when a class template TYPE is redeclared with the indicated
5867 template PARMS, e.g.:
5869 template <class T> struct S;
5870 template <class T> struct S {}; */
5872 bool
5874 {
5875 tree tmpl;
5876 tree tmpl_parms;
5880 {
5883 }
5887 /* The type is nested in some template class. Nothing to worry
5888 about here; there are no new template parameters for the nested
5889 type. */
5893 {
5895 tmpl);
5897 }
5903 {
5913 }
5916 {
5917 tree tmpl_parm;
5918 tree parm;
5919 tree tmpl_default;
5920 tree parm_default;
5934 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5935 TEMPLATE_DECL. */
5945 {
5949 }
5952 {
5953 /* We have in [temp.param]:
5955 A template-parameter may not be given default arguments
5956 by two different declarations in the same scope. */
5961 }
5964 /* Update the previous template parameters (which are the ones
5965 that will really count) with the new default value. */
5968 /* Update the new parameters, too; they'll be used as the
5969 parameters for any members. */
5972 /* Give each template template parm in this redeclaration a
5973 DECL_CONTEXT of the template for which they are a parameter. */
5975 {
5978 }
5982 }
5984 // Cannot redeclare a class template with a different set of constraints.
5986 {
5991 }
5994 }
5996 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5997 to be used when the caller has already checked
5998 (processing_template_decl
5999 && !instantiation_dependent_expression_p (expr)
6000 && potential_constant_expression (expr))
6001 and cleared processing_template_decl. */
6003 tree
6005 {
6008 complain,
6012 }
6014 /* Simplify EXPR if it is a non-dependent expression. Returns the
6015 (possibly simplified) expression. */
6017 tree
6019 {
6023 /* If we're in a template, but EXPR isn't value dependent, simplify
6024 it. We're supposed to treat:
6026 template <typename T> void f(T[1 + 1]);
6027 template <typename T> void f(T[2]);
6029 as two declarations of the same function, for example. */
6032 {
6033 processing_template_decl_sentinel s;
6035 }
6037 }
6039 tree
6041 {
6043 }
6045 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6046 an uninstantiated expression. */
6048 tree
6050 {
6054 {
6057 else
6058 {
6059 processing_template_decl_sentinel s;
6061 }
6062 }
6064 }
6066 /* True iff T is a specialization of a variable template. */
6068 bool
6070 {
6075 }
6077 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6078 template declaration, or a TYPE_DECL for an alias declaration. */
6080 bool
6082 {
6090 }
6092 /* Return TRUE iff T is a specialization of an alias template. */
6094 bool
6096 {
6097 /* It's an alias template specialization if it's an alias and its
6098 TYPE_NAME is a specialization of a primary template. */
6104 }
6106 /* An alias template is complex from a SFINAE perspective if a template-id
6107 using that alias can be ill-formed when the expansion is not, as with
6108 the void_t template. We determine this by checking whether the
6109 expansion for the alias template uses all its template parameters. */
6111 struct uses_all_template_parms_data
6112 {
6115 };
6117 static int
6119 {
6127 }
6129 static bool
6131 {
6146 }
6148 /* Return TRUE iff T is a specialization of a complex alias template with
6149 dependent template-arguments. */
6151 bool
6153 {
6166 }
6168 /* Return the number of innermost template parameters in TMPL. */
6170 static int
6172 {
6175 }
6177 /* Return either TMPL or another template that it is equivalent to under DR
6178 1286: An alias that just changes the name of a template is equivalent to
6179 the other template. */
6181 static tree
6183 {
6186 {
6187 /* Determine if the alias is equivalent to an underlying template. */
6199 tree alias_args = INNERMOST_TEMPLATE_ARGS
6204 /* Alias is equivalent. Strip it and repeat. */
6206 }
6209 }
6211 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6212 must be a reference-to-function or a pointer-to-function type, as specified
6213 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6214 and check that the resulting function has external linkage. */
6216 static tree
6218 tsubst_flags_t complain)
6219 {
6222 linkage_kind linkage;
6237 /* [temp.arg.nontype]/1
6239 A template-argument for a non-type, non-template template-parameter
6240 shall be one of:
6241 [...]
6242 -- the address of an object or function with external [C++11: or
6243 internal] linkage. */
6246 {
6248 {
6254 else
6257 }
6259 }
6263 {
6265 {
6270 else
6274 }
6276 }
6278 accept:
6280 {
6283 else
6285 }
6290 }
6292 /* Subroutine of convert_nontype_argument.
6293 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6294 Emit an error otherwise. */
6296 static bool
6298 tsubst_flags_t complain)
6299 {
6316 {
6321 else
6323 }
6325 }
6327 /* Returns TRUE iff the address of OP is value-dependent.
6329 14.6.2.4 [temp.dep.temp]:
6330 A non-integral non-type template-argument is dependent if its type is
6331 dependent or it has either of the following forms
6332 qualified-id
6333 & qualified-id
6334 and contains a nested-name-specifier which specifies a class-name that
6335 names a dependent type.
6337 We generalize this to just say that the address of a member of a
6338 dependent class is value-dependent; the above doesn't cover the
6339 address of a static data member named with an unqualified-id. */
6341 static bool
6343 {
6344 /* We could use get_inner_reference here, but there's no need;
6345 this is only relevant for template non-type arguments, which
6346 can only be expressed as &id-expression. */
6348 {
6352 }
6355 }
6357 /* The next set of functions are used for providing helpful explanatory
6358 diagnostics for failed overload resolution. Their messages should be
6359 indented by two spaces for consistency with the messages in
6360 call.c */
6362 static int
6364 {
6366 }
6368 /* Other failure functions should call this one, to provide a single function
6369 for setting a breakpoint on. */
6371 static int
6373 {
6375 }
6377 static int
6379 {
6384 }
6386 static int
6388 {
6394 }
6396 static int
6398 {
6402 }
6404 static int
6406 {
6409 " template parameter %qD is not a parameter pack, but "
6413 }
6415 static int
6417 {
6420 " template argument %qE does not match "
6424 }
6426 static int
6428 {
6432 }
6434 static int
6436 {
6442 }
6444 static int
6446 {
6448 {
6453 else
6455 " deduced conflicting values for non-type parameter "
6457 }
6459 }
6461 static int
6463 {
6466 " variable-sized array type %qT is not "
6468 arg);
6470 }
6472 static int
6474 {
6478 arg);
6480 }
6482 static int
6484 {
6486 {
6492 else
6497 }
6499 }
6501 static int
6503 {
6505 }
6507 static int
6510 {
6512 }
6514 static int
6517 {
6523 }
6525 static int
6528 {
6531 {
6539 }
6541 }
6543 static int
6545 {
6548 " template parameters of a template template argument are "
6551 }
6553 static int
6555 {
6561 }
6563 static int
6565 {
6570 }
6572 /* Attempt to convert the non-type template parameter EXPR to the
6573 indicated TYPE. If the conversion is successful, return the
6574 converted value. If the conversion is unsuccessful, return
6575 NULL_TREE if we issued an error message, or error_mark_node if we
6576 did not. We issue error messages for out-and-out bad template
6577 parameters, but not simply because the conversion failed, since we
6578 might be just trying to do argument deduction. Both TYPE and EXPR
6579 must be non-dependent.
6581 The conversion follows the special rules described in
6582 [temp.arg.nontype], and it is much more strict than an implicit
6583 conversion.
6585 This function is called twice for each template argument (see
6586 lookup_template_class for a more accurate description of this
6587 problem). This means that we need to handle expressions which
6588 are not valid in a C++ source, but can be created from the
6589 first call (for instance, casts to perform conversions). These
6590 hacks can go away after we fix the double coercion problem. */
6592 static tree
6594 {
6595 tree expr_type;
6599 /* Detect immediately string literals as invalid non-type argument.
6600 This special-case is not needed for correctness (we would easily
6601 catch this later), but only to provide better diagnostic for this
6602 common user mistake. As suggested by DR 100, we do not mention
6603 linkage issues in the diagnostic as this is not the point. */
6604 /* FIXME we're making this OK. */
6606 {
6612 }
6614 /* Add the ADDR_EXPR now for the benefit of
6615 value_dependent_expression_p. */
6618 {
6622 }
6624 /* If we are in a template, EXPR may be non-dependent, but still
6625 have a syntactic, rather than semantic, form. For example, EXPR
6626 might be a SCOPE_REF, rather than the VAR_DECL to which the
6627 SCOPE_REF refers. Preserving the qualifying scope is necessary
6628 so that access checking can be performed when the template is
6629 instantiated -- but here we need the resolved form so that we can
6630 convert the argument. */
6642 /* If the argument is non-dependent, perform any conversions in
6643 non-dependent context as well. */
6651 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6652 to a non-type argument of "nullptr". */
6656 /* In C++11, integral or enumeration non-type template arguments can be
6657 arbitrary constant expressions. Pointer and pointer to
6658 member arguments can be general constant expressions that evaluate
6659 to a null value, but otherwise still need to be of a specific form. */
6661 {
6663 /* A PTRMEM_CST is already constant, and a valid template
6664 argument for a parameter of pointer to member type, we just want
6665 to leave it in that form rather than lower it to a
6669 {
6670 /* C++17: A template-argument for a non-type template-parameter shall
6671 be a converted constant expression (8.20) of the type of the
6672 template-parameter. */
6678 }
6680 {
6685 }
6686 }
6690 else
6693 /* HACK: Due to double coercion, we can get a
6694 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6695 which is the tree that we built on the first call (see
6696 below when coercing to reference to object or to reference to
6697 function). We just strip everything and get to the arg.
6698 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6699 for examples. */
6701 {
6707 {
6708 /* ??? Maybe we could use convert_from_reference here, but we
6709 would need to relax its constraints because the NOP_EXPR
6710 could actually change the type to something more cv-qualified,
6711 and this is not folded by convert_from_reference. */
6716 && (same_type_ignoring_top_level_qualifiers_p
6719 {
6722 }
6723 }
6724 }
6726 /* [temp.arg.nontype]/5, bullet 1
6728 For a non-type template-parameter of integral or enumeration type,
6729 integral promotions (_conv.prom_) and integral conversions
6730 (_conv.integral_) are applied. */
6732 {
6734 {
6739 }
6744 /* Notice that there are constant expressions like '4 % 0' which
6745 do not fold into integer constants. */
6748 {
6750 {
6754 else
6760 /* else cxx_constant_value complained but gave us
6761 a real constant, so go ahead. */
6763 {
6764 /* Some assemble time constant expressions like
6765 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6766 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6767 as we can emit them into .rodata initializers of
6768 variables, yet they can't fold into an INTEGER_CST at
6769 compile time. Refuse them here. */
6774 }
6775 }
6776 else
6778 }
6780 /* Avoid typedef problems. */
6783 }
6784 /* [temp.arg.nontype]/5, bullet 2
6786 For a non-type template-parameter of type pointer to object,
6787 qualification conversions (_conv.qual_) and the array-to-pointer
6788 conversion (_conv.array_) are applied. */
6790 {
6793 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6794 decay_conversion or an explicit cast. If it's a problematic cast,
6795 we'll complain about it below. */
6797 {
6802 {
6805 }
6806 }
6808 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6810 A template-argument for a non-type, non-template template-parameter
6811 shall be one of: [...]
6813 -- the name of a non-type template-parameter;
6814 -- the address of an object or function with external linkage, [...]
6815 expressed as "& id-expression" where the & is optional if the name
6816 refers to a function or array, or if the corresponding
6817 template-parameter is a reference.
6819 Here, we do not care about functions, as they are invalid anyway
6820 for a parameter of type pointer-to-object. */
6823 /* Non-type template parameters are OK. */
6824 ;
6828 {
6830 {
6833 "because %qD is a variable, not the address of "
6836 }
6838 {
6844 }
6845 /* Other values, like integer constants, might be valid
6846 non-type arguments of some other type. */
6848 }
6849 else
6850 {
6854 {
6859 }
6861 {
6867 }
6870 {
6875 }
6876 /* C++17: For a non-type template-parameter of reference or pointer
6877 type, the value of the constant expression shall not refer to (or
6878 for a pointer type, shall not be the address of):
6879 * a subobject (4.5),
6880 * a temporary object (15.2),
6881 * a string literal (5.13.5),
6882 * the result of a typeid expression (8.2.8), or
6883 * a predefined __func__ variable (11.4.1). */
6885 {
6888 decl);
6890 }
6894 {
6899 }
6901 {
6905 decl);
6907 }
6908 }
6915 }
6916 /* [temp.arg.nontype]/5, bullet 3
6918 For a non-type template-parameter of type reference to object, no
6919 conversions apply. The type referred to by the reference may be more
6920 cv-qualified than the (otherwise identical) type of the
6921 template-argument. The template-parameter is bound directly to the
6922 template-argument, which must be an lvalue. */
6924 {
6926 expr_type))
6930 {
6935 }
6938 {
6943 }
6945 /* [temp.arg.nontype]/1
6947 A template-argument for a non-type, non-template template-parameter
6948 shall be one of: [...]
6950 -- the address of an object or function with external linkage. */
6953 {
6956 {
6959 "because a reference variable does not have a constant "
6962 }
6963 }
6967 /* OK, dependent reference. We don't want to ask whether a DECL is
6969 else
6970 {
6972 {
6978 }
6980 /* DR 1155 allows internal linkage in C++11 and up. */
6983 {
6989 }
6992 }
6996 }
6997 /* [temp.arg.nontype]/5, bullet 4
6999 For a non-type template-parameter of type pointer to function, only
7000 the function-to-pointer conversion (_conv.func_) is applied. If the
7001 template-argument represents a set of overloaded functions (or a
7002 pointer to such), the matching function is selected from the set
7003 (_over.over_). */
7005 {
7006 /* If the argument is a template-id, we might not have enough
7007 context information to decay the pointer. */
7009 {
7013 }
7016 /* Null pointer values are OK in C++11. */
7022 }
7023 /* [temp.arg.nontype]/5, bullet 5
7025 For a non-type template-parameter of type reference to function, no
7026 conversions apply. If the template-argument represents a set of
7027 overloaded functions, the matching function is selected from the set
7028 (_over.over_). */
7030 {
7032 {
7034 {
7039 }
7041 }
7046 }
7047 /* [temp.arg.nontype]/5, bullet 6
7049 For a non-type template-parameter of type pointer to member function,
7050 no conversions apply. If the template-argument represents a set of
7051 overloaded member functions, the matching member function is selected
7052 from the set (_over.over_). */
7054 {
7059 /* [temp.arg.nontype] bullet 1 says the pointer to member
7060 expression must be a pointer-to-member constant. */
7065 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7066 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7069 }
7070 /* [temp.arg.nontype]/5, bullet 7
7072 For a non-type template-parameter of type pointer to data member,
7073 qualification conversions (_conv.qual_) are applied. */
7075 {
7076 /* [temp.arg.nontype] bullet 1 says the pointer to member
7077 expression must be a pointer-to-member constant. */
7085 }
7087 {
7089 {
7094 }
7096 }
7097 /* A template non-type parameter must be one of the above. */
7098 else
7101 /* Sanity check: did we actually convert the argument to the
7102 right type? */
7106 }
7108 /* Subroutine of coerce_template_template_parms, which returns 1 if
7109 PARM_PARM and ARG_PARM match using the rule for the template
7110 parameters of template template parameters. Both PARM and ARG are
7111 template parameters; the rest of the arguments are the same as for
7112 coerce_template_template_parms.
7113 */
7114 static int
7116 tree arg,
7117 tsubst_flags_t complain,
7118 tree in_decl,
7119 tree outer_args)
7120 {
7129 {
7131 /* We encounter instantiations of templates like
7132 template <template <template <class> class> class TT>
7133 class C; */
7134 {
7141 }
7142 /* Fall through. */
7147 /* Argument is a parameter pack but parameter is not. */
7152 /* The tsubst call is used to handle cases such as
7154 template <int> class C {};
7155 template <class T, template <T> class TT> class D {};
7156 D<int, C> d;
7158 i.e. the parameter list of TT depends on earlier parameters. */
7160 {
7165 }
7169 /* Argument is a parameter pack but parameter is not. */
7176 }
7179 }
7181 /* Coerce template argument list ARGLIST for use with template
7182 template-parameter TEMPL. */
7184 static tree
7186 tsubst_flags_t complain)
7187 {
7188 /* Consider an example where a template template parameter declared as
7190 template <class T, class U = std::allocator<T> > class TT
7192 The template parameter level of T and U are one level larger than
7193 of TT. To proper process the default argument of U, say when an
7194 instantiation `TT<int>' is seen, we need to build the full
7195 arguments containing {int} as the innermost level. Outer levels,
7196 available when not appearing as default template argument, can be
7197 obtained from the arguments of the enclosing template.
7199 Suppose that TT is later substituted with std::vector. The above
7200 instantiation is `TT<int, std::allocator<T> >' with TT at
7201 level 1, and T at level 2, while the template arguments at level 1
7202 becomes {std::vector} and the inner level 2 is {int}. */
7206 {
7208 /* We want arguments for the partial specialization, not arguments for
7209 the primary template. */
7211 else
7213 }
7215 {
7216 /* This is an argument of the current template, so we haven't set
7217 DECL_CONTEXT yet. */
7218 tree relevant_template_parms;
7220 /* Parameter levels that are greater than the level of the given
7221 template template parm are irrelevant. */
7228 }
7235 complain,
7238 }
7240 /* A cache of template template parameters with match-all default
7241 arguments. */
7243 static void
7245 {
7249 }
7250 static tree
7252 {
7257 }
7259 /* T is a bound template template-parameter. Copy its arguments into default
7260 arguments of the template template-parameter's template parameters. */
7262 static tree
7264 {
7287 {
7290 {
7293 }
7294 }
7298 }
7300 /* ARG is a bound potential template template-argument, and PARGS is a list
7301 of arguments for the corresponding template template-parameter. Adjust
7302 PARGS as appropriate for application to ARG's template, and if ARG is a
7303 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7304 arguments to the template template parameter. */
7306 static tree
7308 {
7312 {
7313 /* When comparing two template template-parameters in partial ordering,
7314 rewrite the one currently being used as an argument to have default
7315 arguments for all parameters. */
7321 }
7322 else
7323 {
7324 tree aparms
7329 }
7332 }
7334 /* Subroutine of unify for the case when PARM is a
7335 BOUND_TEMPLATE_TEMPLATE_PARM. */
7337 static int
7340 {
7344 /* The template template parm might be variadic and the argument
7345 not, so flatten both argument lists. */
7350 {
7351 /* In keeping with P0522R0, adjust P's template arguments
7352 to apply to A's template; then flatten it again. */
7361 /* If the P0522 adjustment eliminated a pack expansion, deduce
7362 empty packs. */
7368 }
7369 else
7370 {
7371 /* Deduce arguments T, i from TT<T> or TT<i>.
7372 We check each element of PARMVEC and ARGVEC individually
7373 rather than the whole TREE_VEC since they can have
7374 different number of elements, which is allowed under N2555. */
7378 /* Check if the parameters end in a pack, making them
7379 variadic. */
7386 /* If the template argument list of P contains a pack
7387 expansion that is not the last template argument, the
7388 entire template argument list is a non-deduced
7389 context. */
7407 DEDUCE_EXACT,
7410 }
7413 }
7415 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7416 template template parameters. Both PARM_PARMS and ARG_PARMS are
7417 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7418 or PARM_DECL.
7420 Consider the example:
7421 template <class T> class A;
7422 template<template <class U> class TT> class B;
7424 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7425 the parameters to A, and OUTER_ARGS contains A. */
7427 static int
7429 tree arg_parms,
7430 tsubst_flags_t complain,
7431 tree in_decl,
7432 tree outer_args)
7433 {
7445 {
7446 /* P0522R0: A template template-parameter P is at least as specialized as
7447 a template template-argument A if, given the following rewrite to two
7448 function templates, the function template corresponding to P is at
7449 least as specialized as the function template corresponding to A
7450 according to the partial ordering rules for function templates
7451 ([temp.func.order]). Given an invented class template X with the
7452 template parameter list of A (including default arguments):
7454 * Each of the two function templates has the same template parameters,
7455 respectively, as P or A.
7457 * Each function template has a single function parameter whose type is
7458 a specialization of X with template arguments corresponding to the
7459 template parameters from the respective function template where, for
7460 each template parameter PP in the template parameter list of the
7461 function template, a corresponding template argument AA is formed. If
7462 PP declares a parameter pack, then AA is the pack expansion
7463 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7465 If the rewrite produces an invalid type, then P is not at least as
7466 specialized as A. */
7468 /* So coerce P's args to apply to A's parms, and then deduce between A's
7469 args and the converted args. If that succeeds, A is at least as
7470 specialized as P, so they match.*/
7477 {
7483 }
7484 }
7486 /* Determine whether we have a parameter pack at the end of the
7487 template template parameter's template parameter list. */
7489 {
7496 {
7510 }
7511 }
7517 /* Check all of the template parameters except the parameter pack at
7518 the end (if any). */
7520 {
7529 outer_args))
7532 }
7535 {
7536 /* Check each of the template parameters in the template
7537 argument against the template parameter pack at the end of
7538 the template template parameter. */
7545 {
7552 outer_args))
7554 }
7555 }
7558 }
7560 /* Verifies that the deduced template arguments (in TARGS) for the
7561 template template parameters (in TPARMS) represent valid bindings,
7562 by comparing the template parameter list of each template argument
7563 to the template parameter list of its corresponding template
7564 template parameter, in accordance with DR150. This
7565 routine can only be called after all template arguments have been
7566 deduced. It will return TRUE if all of the template template
7567 parameter bindings are okay, FALSE otherwise. */
7568 bool
7570 {
7574 /* We're dealing with template parms in this process. */
7580 {
7585 {
7590 {
7591 /* Look inside the argument pack. */
7594 }
7597 {
7601 /* Extract the next argument from the argument
7602 pack. */
7606 /* Look at the pattern of the pack expansion. */
7609 /* Extract the template parameters from the template
7610 argument. */
7616 /* Verify that we can coerce the template template
7617 parameters from the template argument to the template
7618 parameter. This requires an exact match. */
7620 && !coerce_template_template_parms
7622 targ_parms,
7623 tf_none,
7624 tparm,
7625 targs))
7626 {
7629 }
7630 }
7631 }
7632 }
7634 out:
7638 }
7640 /* Since type attributes aren't mangled, we need to strip them from
7641 template type arguments. */
7643 static tree
7645 {
7655 }
7657 /* And from inside dependent non-type arguments like sizeof(Type). */
7659 static tree
7661 {
7671 }
7673 // A template declaration can be substituted for a constrained
7674 // template template parameter only when the argument is more
7675 // constrained than the parameter.
7676 static bool
7678 {
7681 /* For now, allow constrained template template arguments
7682 and unconstrained template template parameters. */
7688 // If the template parameter is constrained, we need to rewrite its
7689 // constraints in terms of the ARG's template parameters. This ensures
7690 // that all of the template parameter types will have the same depth.
7691 //
7692 // Note that this is only valid when coerce_template_template_parm is
7693 // true for the innermost template parameters of PARM and ARG. In other
7694 // words, because coercion is successful, this conversion will be valid.
7696 {
7703 }
7706 }
7708 // Convert a placeholder argument into a binding to the original
7709 // parameter. The original parameter is saved as the TREE_TYPE of
7710 // ARG.
7713 {
7716 }
7718 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7719 because one of them is dependent. But we need to represent the
7720 conversion for the benefit of cp_tree_equal. */
7722 static tree
7724 {
7725 /* Auto parms get no conversion. */
7728 /* We don't need or want to add this conversion now if we're going to use the
7729 argument for deduction. */
7741 }
7743 /* Convert the indicated template ARG as necessary to match the
7744 indicated template PARM. Returns the converted ARG, or
7745 error_mark_node if the conversion was unsuccessful. Error and
7746 warning messages are issued under control of COMPLAIN. This
7747 conversion is for the Ith parameter in the parameter list. ARGS is
7748 the full set of template arguments deduced so far. */
7750 static tree
7752 tree arg,
7753 tree args,
7754 tsubst_flags_t complain,
7756 tree in_decl)
7757 {
7758 tree orig_arg;
7759 tree val;
7765 /* Trivially convert placeholders. */
7774 {
7775 /* The template argument was the name of some
7776 member function. That's usually
7777 invalid, but static members are OK. In any
7778 case, grab the underlying fields/functions
7779 and issue an error later if required. */
7782 }
7790 /* When determining whether an argument pack expansion is a template,
7791 look at the pattern. */
7795 /* Deal with an injected-class-name used as a template template arg. */
7797 {
7800 {
7810 }
7811 }
7813 is_tmpl_type =
7829 {
7831 {
7835 }
7838 "to refer to a type member of a template parameter, "
7843 typename_type,
7844 complain);
7847 }
7849 {
7851 {
7853 {
7865 else
7868 }
7869 }
7871 }
7873 {
7875 {
7882 else
7885 }
7887 }
7890 /* We already did the appropriate conversion when packing args. */
7893 {
7895 {
7897 /* The number of argument required is not known yet.
7898 Just accept it for now. */
7900 else
7901 {
7903 tree argparm;
7905 /* Strip alias templates that are equivalent to another
7906 template. */
7912 args))
7913 {
7916 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7917 TEMPLATE_DECL. */
7919 {
7924 }
7925 }
7926 else
7927 {
7929 {
7936 }
7939 }
7941 // Check that the constraints are compatible before allowing the
7942 // substitution.
7945 {
7947 {
7953 }
7955 }
7956 }
7957 }
7958 else
7960 /* We only form one instance of each template specialization.
7961 Therefore, if we use a non-canonical variant (i.e., a
7962 typedef), any future messages referring to the type will use
7963 the typedef, which is confusing if those future uses do not
7964 themselves also use the typedef. */
7967 }
7968 else
7969 {
7974 /* We don't have enough levels of args to do any substitution. This
7977 {
7981 }
7982 else
7990 /* We used to call digest_init here. However, digest_init
7991 will report errors, which we don't want when complain
7992 is zero. More importantly, digest_init will try too
7993 hard to convert things: for example, `0' should not be
7994 converted to pointer type at this point according to
7995 the standard. Accepting this is not merely an
7996 extension, since deciding whether or not these
7997 conversions can occur is part of determining which
7998 function template to call, or whether a given explicit
7999 argument specification is valid. */
8001 else
8002 {
8005 }
8015 {
8016 /* Reject template arguments that are references to built-in
8017 functions with no library fallbacks. */
8026 }
8029 {
8030 /* Strip typedefs from the SCOPE_REF. */
8033 complain);
8036 }
8037 }
8040 }
8042 /* Coerces the remaining template arguments in INNER_ARGS (from
8043 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8044 Returns the coerced argument pack. PARM_IDX is the position of this
8045 parameter in the template parameter list. ARGS is the original
8046 template argument list. */
8047 static tree
8050 tree args,
8051 tree inner_args,
8053 tree new_args,
8055 tree in_decl,
8056 tsubst_flags_t complain)
8057 {
8060 tree packed_args;
8061 tree argument_pack;
8068 {
8069 /* When the template parameter is a non-type template parameter pack
8070 or template template parameter pack whose type or template
8071 parameters use parameter packs, we know exactly how many arguments
8072 we are looking for. Build a vector of the instantiated decls for
8073 these template parameters in PACKED_PARMS. */
8074 /* We can't use make_pack_expansion here because it would interpret a
8075 _DECL as a use rather than a declaration. */
8089 /* If we're doing a partial instantiation of a member template,
8090 verify that all of the types used for the non-type
8091 template parameter pack are, in fact, valid for non-type
8092 template parameters. */
8095 {
8098 {
8102 }
8103 /* We don't know how many args we have yet, just
8104 use the unconverted ones for now. */
8106 }
8109 }
8110 /* Check if we have a placeholder pack, which indicates we're
8111 in the context of a introduction list. In that case we want
8112 to match this pack to the single placeholder. */
8116 {
8119 }
8120 else
8123 /* Convert the remaining arguments, which will be a part of the
8124 parameter pack "parm". */
8127 {
8133 {
8134 /* Once we've packed as many args as we have types, stop. */
8138 /* We don't know how many args we have yet, just
8139 use the unconverted ones for now. */
8141 else
8143 }
8146 {
8149 }
8150 else
8153 in_decl);
8157 }
8161 {
8166 }
8171 else
8172 {
8175 }
8182 }
8184 /* Returns the number of pack expansions in the template argument vector
8185 ARGS. */
8187 static int
8189 {
8194 {
8198 }
8200 }
8202 /* Convert all template arguments to their appropriate types, and
8203 return a vector containing the innermost resulting template
8204 arguments. If any error occurs, return error_mark_node. Error and
8205 warning messages are issued under control of COMPLAIN.
8207 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8208 for arguments not specified in ARGS. Otherwise, if
8209 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8210 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8211 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8212 ARGS. */
8214 static tree
8216 tree args,
8217 tree in_decl,
8218 tsubst_flags_t complain,
8221 {
8223 tree orig_inner_args;
8224 tree inner_args;
8225 tree new_args;
8226 tree new_inner_args;
8230 /* When used as a boolean value, indicates whether this is a
8231 variadic template parameter list. Since it's an int, we can also
8232 subtract it from nparms to get the number of non-variadic
8233 parameters. */
8238 /* Adjustment to nparms for fixed parameter packs. */
8243 /* Likewise for parameters with default arguments. */
8251 /* Determine if there are any parameter packs or default arguments. */
8253 {
8261 }
8264 /* If there are no parameters that follow a parameter pack, we need to
8265 expand any argument packs so that we can deduce a parameter pack from
8266 some non-packed args followed by an argument pack, as in variadic85.C.
8267 If there are such parameters, we need to leave argument packs intact
8268 so the arguments are assigned properly. This can happen when dealing
8269 with a nested class inside a partial specialization of a class
8270 template, as in variadic92.C, or when deducing a template parameter pack
8271 from a sub-declarator, as in variadic114.C. */
8275 /* Count any pack expansion args. */
8281 && require_all_args
8282 && !variadic_args_p
8283 && (!use_default_args
8286 {
8287 bad_nargs:
8289 {
8291 {
8295 }
8296 else
8303 }
8306 }
8307 /* We can't pass a pack expansion to a non-pack parameter of an alias
8308 template (DR 1430). */
8312 && variadic_args_p
8314 {
8316 {
8318 {
8324 {
8327 "pack expansion argument for non-pack parameter "
8329 else
8331 "pack expansion argument for non-pack parameter "
8335 }
8336 }
8338 found:;
8339 }
8341 }
8343 /* We need to evaluate the template arguments, even though this
8344 template-id may be nested within a "sizeof". */
8353 {
8354 tree arg;
8355 tree parm;
8357 /* Get the Ith template parameter. */
8361 {
8364 }
8366 /* Calculate the next argument. */
8369 else
8374 {
8375 /* Some arguments will be placed in the
8376 template parameter pack PARM. */
8383 {
8384 /* We don't know how many args we have yet, just use the
8385 unconverted (and still packed) ones for now. */
8389 }
8393 /* Store this argument. */
8395 {
8396 lost++;
8397 /* We are done with all of the arguments. */
8400 }
8401 else
8402 {
8406 {
8409 }
8410 }
8413 }
8415 {
8417 {
8418 /* "If every valid specialization of a variadic template
8419 requires an empty template parameter pack, the template is
8420 ill-formed, no diagnostic required." So check that the
8421 pattern works with this parameter. */
8426 in_decl);
8428 {
8433 }
8435 /* Recover from missing typename. */
8439 /* We don't know how many args we have yet, just
8440 use the unconverted ones for now. */
8444 }
8445 }
8447 {
8448 /* There must be a default arg in this case. */
8451 /* The position of the first default template argument,
8452 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8453 Record that. */
8457 }
8458 else
8462 {
8465 }
8467 {
8468 /* This can occur if there was an error in the template
8469 parameter list itself (which we would already have
8470 reported) that we are trying to recover from, e.g., a class
8471 template with a parameter list such as
8472 template<typename..., typename> (cpp0x/variadic150.C). */
8475 /* This can also happen with a fixed parameter pack (71834). */
8478 }
8479 else
8485 lost++;
8487 }
8492 {
8493 /* If we had fixed parameter packs, we didn't know how many arguments we
8494 actually needed earlier; now we do. */
8498 }
8501 {
8504 }
8511 }
8513 /* Convert all template arguments to their appropriate types, and
8514 return a vector containing the innermost resulting template
8515 arguments. If any error occurs, return error_mark_node. Error and
8516 warning messages are not issued.
8518 Note that no function argument deduction is performed, and default
8519 arguments are used to fill in unspecified arguments. */
8520 tree
8522 {
8524 }
8526 /* Convert all template arguments to their appropriate type, and
8527 instantiate default arguments as needed. This returns a vector
8528 containing the innermost resulting template arguments, or
8529 error_mark_node if unsuccessful. */
8530 tree
8532 tsubst_flags_t complain)
8533 {
8535 }
8537 /* Like coerce_template_parms. If PARMS represents all template
8538 parameters levels, this function returns a vector of vectors
8539 representing all the resulting argument levels. Note that in this
8540 case, only the innermost arguments are coerced because the
8541 outermost ones are supposed to have been coerced already.
8543 Otherwise, if PARMS represents only (the innermost) vector of
8544 parameters, this function returns a vector containing just the
8545 innermost resulting arguments. */
8547 static tree
8549 tree args,
8550 tree in_decl,
8551 tsubst_flags_t complain,
8554 {
8557 tree coerced_args;
8560 {
8562 tree level;
8568 {
8569 tree l;
8573 require_all_args,
8574 use_default_args);
8575 else
8582 }
8583 }
8584 else
8587 require_all_args,
8588 use_default_args);
8590 }
8592 /* Returns 1 if template args OT and NT are equivalent. */
8594 int
8596 {
8605 /* For member templates */
8614 {
8631 }
8635 {
8638 /* Don't treat an alias template specialization with dependent
8639 arguments as equivalent to its underlying type when used as a
8640 template argument; we need them to be distinct so that we
8641 substitute into the specialization arguments at instantiation
8642 time. And aliases can't be equivalent without being ==, so
8643 we don't need to look any deeper.
8645 During partial ordering, however, we need to treat them normally so
8646 that we can order uses of the same alias with different
8647 cv-qualification (79960). */
8651 else
8653 }
8656 else
8657 {
8658 /* Try to treat a template non-type argument that has been converted
8659 to the parameter type as equivalent to one that hasn't yet. */
8672 }
8673 }
8675 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8676 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8677 NEWARG_PTR with the offending arguments if they are non-NULL. */
8679 int
8683 {
8696 {
8701 {
8707 }
8708 }
8710 }
8714 {
8716 }
8718 static void
8720 {
8730 /* We are called both from instantiate_decl, where we've already had a
8731 tinst_level pushed, and instantiate_template, where we haven't.
8732 Compensate. */
8743 else
8752 }
8755 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8756 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8757 documentation for TEMPLATE_ID_EXPR. */
8759 tree
8761 {
8762 tree type;
8770 {
8773 }
8776 {
8778 unknown_type_node,
8780 arglist);
8782 }
8789 }
8791 /* Within the scope of a template class S<T>, the name S gets bound
8792 (in build_self_reference) to a TYPE_DECL for the class, not a
8793 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8794 or one of its enclosing classes, and that type is a template,
8795 return the associated TEMPLATE_DECL. Otherwise, the original
8796 DECL is returned.
8798 Also handle the case when DECL is a TREE_LIST of ambiguous
8799 injected-class-names from different bases. */
8801 tree
8803 {
8807 /* DR 176: A lookup that finds an injected-class-name (10.2
8808 [class.member.lookup]) can result in an ambiguity in certain cases
8809 (for example, if it is found in more than one base class). If all of
8810 the injected-class-names that are found refer to specializations of
8811 the same class template, and if the name is followed by a
8812 template-argument-list, the reference refers to the class template
8813 itself and not a specialization thereof, and is not ambiguous. */
8815 {
8818 {
8824 }
8827 else
8829 }
8835 }
8837 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8838 parameters, find the desired type.
8840 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8842 IN_DECL, if non-NULL, is the template declaration we are trying to
8843 instantiate.
8845 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8846 the class we are looking up.
8848 Issue error and warning messages under control of COMPLAIN.
8850 If the template class is really a local class in a template
8851 function, then the FUNCTION_CONTEXT is the function in which it is
8852 being instantiated.
8854 ??? Note that this function is currently called *twice* for each
8855 template-id: the first time from the parser, while creating the
8856 incomplete type (finish_template_type), and the second type during the
8857 real instantiation (instantiate_template_class). This is surely something
8858 that we want to avoid. It also causes some problems with argument
8859 coercion (see convert_nontype_argument for more information on this). */
8861 static tree
8864 {
8866 tree t;
8869 spec_entry elt;
8870 hashval_t hash;
8873 {
8877 else
8878 {
8885 }
8888 }
8890 {
8893 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8894 an implicit typename for the second A. Deal with it. */
8899 {
8902 }
8903 }
8906 {
8909 }
8911 {
8915 }
8917 {
8920 }
8922 /* Issue an error message if we didn't find a template. */
8924 {
8928 }
8931 /* Make sure it's a user visible template, if it was named by
8932 the user. */
8935 {
8937 {
8941 }
8943 }
8947 /* An alias that just changes the name of a template is equivalent to the
8948 other template, so if any of the arguments are pack expansions, strip
8949 the alias to avoid problems with a pack expansion passed to a non-pack
8950 alias template parameter (DR 1430). */
8955 {
8956 tree parm;
8965 }
8966 else
8967 {
8969 tree gen_tmpl;
8970 tree type_decl;
8978 /* An error occurred while building the template TEMPL, and a
8979 diagnostic has most certainly been emitted for that
8980 already. Let's propagate that error. */
8989 {
8990 /* We've been given an incomplete set of template arguments.
8991 For example, given:
8993 template <class T> struct S1 {
8994 template <class U> struct S2 {};
8995 template <class U> struct S2<U*> {};
8996 };
8998 we will be called with an ARGLIST of `U*', but the
8999 TEMPLATE will be `template <class T> template
9000 <class U> struct S1<T>::S2'. We must fill in the missing
9001 arguments. */
9005 }
9007 /* Now we should have enough arguments. */
9010 /* From here on, we're only interested in the most general
9011 template. */
9013 /* Calculate the BOUND_ARGS. These will be the args that are
9014 actually tsubst'd into the definition to create the
9015 instantiation. */
9017 complain,
9022 /* We were unable to bind the arguments. */
9025 /* In the scope of a template class, explicit references to the
9026 template class refer to the type of the template, not any
9027 instantiation of it. For example, in:
9029 template <class T> class C { void f(C<T>); }
9031 the `C<T>' is just the same as `C'. Outside of the
9032 class, however, such a reference is an instantiation. */
9036 {
9041 }
9043 /* If we already have this specialization, return it. */
9053 /* If the the template's constraints are not satisfied,
9054 then we cannot form a valid type.
9056 Note that the check is deferred until after the hash
9057 lookup. This prevents redundant checks on previously
9058 instantiated specializations. */
9060 {
9062 {
9065 }
9067 }
9071 /* If the deduced arguments are invalid, then the binding
9072 failed. */
9076 complain))
9083 {
9088 }
9098 /* Create the type. */
9100 {
9101 /* The user referred to a specialization of an alias
9102 template represented by GEN_TMPL.
9104 [temp.alias]/2 says:
9106 When a template-id refers to the specialization of an
9107 alias template, it is equivalent to the associated
9108 type obtained by substitution of its
9109 template-arguments for the template-parameters in the
9110 type-id of the alias template. */
9113 /* Note that the call above (by indirectly calling
9114 register_specialization in tsubst_decl) registers the
9115 TYPE_DECL representing the specialization of the alias
9116 template. So next time someone substitutes ARGLIST for
9117 the template parms into the alias template (GEN_TMPL),
9118 she'll get that TYPE_DECL back. */
9122 }
9124 {
9126 {
9137 }
9138 else
9139 {
9140 /* We don't want to call start_enum for this type, since
9141 the values for the enumeration constants may involve
9142 template parameters. And, no one should be interested
9143 in the enumeration constants for such a type. */
9146 }
9150 }
9152 {
9153 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9154 instantiated here. */
9162 /* A local class. Make sure the decl gets registered properly. */
9167 /* This instantiation is another name for the primary
9168 template type. Set the TYPE_CANONICAL field
9169 appropriately. */
9172 /* Some of the template arguments require structural
9173 equality testing, so this template class requires
9174 structural equality testing. */
9176 }
9177 else
9180 /* If we called start_enum or pushtag above, this information
9181 will already be set up. */
9183 {
9190 }
9191 else
9195 {
9201 {
9204 }
9205 }
9209 {
9213 {
9214 tree attributes
9222 }
9223 }
9225 /* Let's consider the explicit specialization of a member
9226 of a class template specialization that is implicitly instantiated,
9227 e.g.:
9228 template<class T>
9229 struct S
9230 {
9231 template<class U> struct M {}; //#0
9232 };
9234 template<>
9235 template<>
9236 struct S<int>::M<char> //#1
9237 {
9238 int i;
9239 };
9240 [temp.expl.spec]/4 says this is valid.
9242 In this case, when we write:
9243 S<int>::M<char> m;
9245 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9246 the one of #0.
9248 When we encounter #1, we want to store the partial instantiation
9249 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9251 For all cases other than this "explicit specialization of member of a
9252 class template", we just want to store the most general template into
9253 the CLASSTYPE_TI_TEMPLATE of M.
9255 This case of "explicit specialization of member of a class template"
9256 only happens when:
9257 1/ the enclosing class is an instantiation of, and therefore not
9258 the same as, the context of the most general template, and
9259 2/ we aren't looking at the partial instantiation itself, i.e.
9260 the innermost arguments are not the same as the innermost parms of
9261 the most general template.
9263 So it's only when 1/ and 2/ happens that we want to use the partial
9264 instantiation of the member template in lieu of its most general
9265 template. */
9269 /* the enclosing class must be an instantiation... */
9272 {
9276 tree partial_inst_args =
9283 use_partial_inst_tmpl =
9284 /*...and we must not be looking at the partial instantiation
9285 itself. */
9287 partial_inst_args);
9288 }
9291 /* This case is easy; there are no member templates involved. */
9293 else
9294 {
9295 /* This is a full instantiation of a member template. Find
9296 the partial instantiation of which this is an instance. */
9298 /* Temporarily reduce by one the number of levels in the ARGLIST
9299 so as to avoid comparing the last set of arguments. */
9303 /* FOUND is either a proper class type, or an alias
9304 template specialization. In the later case, it's a
9305 TYPE_DECL, resulting from the substituting of arguments
9306 for parameters in the TYPE_DECL of the alias template
9307 done earlier. So be careful while getting the template
9308 of FOUND. */
9310 ? found
9314 }
9316 // Build template info for the new specialization.
9325 /* Note this use of the partial instantiation so we can check it
9326 later in maybe_process_partial_specialization. */
9333 /* Now that the type has been registered on the instantiations
9334 list, we set up the enumerators. Because the enumeration
9335 constants may involve the enumeration type itself, we make
9336 sure to register the type first, and then create the
9337 constants. That way, doing tsubst_expr for the enumeration
9338 constants won't result in recursive calls here; we'll find
9339 the instantiation and exit above. */
9343 /* If the type makes use of template parameters, the
9344 code that generates debugging information will crash. */
9347 /* Possibly limit visibility based on template args. */
9354 }
9355 }
9357 /* Wrapper for lookup_template_class_1. */
9359 tree
9362 {
9363 tree ret;
9369 }
9371 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9373 tree
9375 {
9376 /* The type of the expression is NULL_TREE since the template-id could refer
9377 to an explicit or partial specialization. */
9380 /* Except that concepts are always bool. */
9383 }
9385 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9387 tree
9389 {
9393 /* We never want to return a VAR_DECL for a variable concept, since they
9394 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9409 {
9411 {
9414 }
9416 }
9418 /* If a template-id refers to a specialization of a variable
9419 concept, then the expression is true if and only if the
9420 concept's constraints are satisfied by the given template
9421 arguments.
9423 NOTE: This is an extension of Concepts Lite TS that
9424 allows constraints to be used in expressions. */
9426 {
9429 }
9432 }
9434 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9435 TARGS template args, and instantiate it if it's not dependent. */
9437 tree
9439 tsubst_flags_t complain)
9440 {
9443 {
9446 }
9449 }
9451 \f
9452 struct pair_fn_data
9453 {
9454 tree_fn_t fn;
9455 tree_fn_t any_fn;
9457 /* True when we should also visit template parameters that occur in
9458 non-deduced contexts. */
9461 };
9463 /* Called from for_each_template_parm via walk_tree. */
9465 static tree
9467 {
9474 #define WALK_SUBTREE(NODE) \
9475 do \
9476 { \
9477 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9478 pfd->include_nondeduced_p, \
9479 pfd->any_fn); \
9480 if (result) goto out; \
9481 } \
9482 while (0)
9492 {
9496 /* Fall through. */
9502 else
9512 /* Since we're not going to walk subtrees, we have to do this
9513 explicitly here. */
9515 /* Fall through. */
9518 /* Check the return type. */
9521 /* Check the parameter types. Since default arguments are not
9522 instantiated until they are needed, the TYPE_ARG_TYPES may
9523 contain expressions that involve template parameters. But,
9524 no-one should be looking at them yet. And, once they're
9525 instantiated, they don't contain template parameters, so
9526 there's no point in looking at them then, either. */
9527 {
9528 tree parm;
9533 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9534 want walk_tree walking into them itself. */
9536 }
9539 {
9543 }
9560 /* Fall through. */
9572 /* Record template parameters such as `T' inside `TT<T>'. */
9574 /* Fall through. */
9586 /* A template template parameter is encountered. */
9590 /* Already substituted template template parameter */
9595 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9596 partial instantiation. */
9608 /* If there's no type, then this thing must be some expression
9609 involving template parameters. */
9631 }
9633 #undef WALK_SUBTREE
9635 /* We didn't find any template parameters we liked. */
9636 out:
9638 }
9640 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9641 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9642 call FN with the parameter and the DATA.
9643 If FN returns nonzero, the iteration is terminated, and
9644 for_each_template_parm returns 1. Otherwise, the iteration
9645 continues. If FN never returns a nonzero value, the value
9646 returned by for_each_template_parm is 0. If FN is NULL, it is
9647 considered to be the function which always returns 1.
9649 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9650 parameters that occur in non-deduced contexts. When false, only
9651 visits those template parameters that can be deduced. */
9653 static tree
9657 tree_fn_t any_fn)
9658 {
9660 tree result;
9662 /* Set up. */
9668 /* Walk the tree. (Conceptually, we would like to walk without
9669 duplicates, but for_each_template_parm_r recursively calls
9670 for_each_template_parm, so we would need to reorganize a fair
9671 bit to use walk_tree_without_duplicates, so we keep our own
9672 visited list.) */
9675 else
9678 for_each_template_parm_r,
9682 /* Clean up. */
9684 {
9687 }
9690 }
9692 /* Returns true if T depends on any template parameter. */
9694 int
9696 {
9726 else
9727 {
9730 }
9735 }
9737 /* Returns true iff current_function_decl is an incompletely instantiated
9738 template. Useful instead of processing_template_decl because the latter
9739 is set to 0 during instantiate_non_dependent_expr. */
9741 bool
9743 {
9752 }
9754 /* Returns true if T depends on any template parameter with level LEVEL. */
9756 bool
9758 {
9761 }
9763 /* Returns true if the signature of DECL depends on any template parameter from
9764 its enclosing class. */
9766 bool
9768 {
9778 template_parm_outer_level,
9788 }
9790 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9791 ill-formed translation unit, i.e. a variable or function that isn't
9792 usable in a constant expression. */
9796 {
9801 }
9803 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9804 neglectable and instantiated from within an erroneous instantiation. */
9806 static bool
9808 {
9819 }
9827 /* We're starting to instantiate D; record the template instantiation context
9828 for diagnostics and to restore it later. */
9830 bool
9832 {
9834 }
9836 /* We're starting to instantiate D; record the template instantiation context
9837 at LOC for diagnostics and to restore it later. */
9839 bool
9841 {
9845 {
9846 /* Tell error.c not to try to instantiate any templates. */
9849 "template instantiation depth exceeds maximum of %d"
9851 max_tinst_depth);
9853 }
9855 /* If the current instantiation caused problems, don't let it instantiate
9856 anything else. Do allow deduction substitution and decls usable in
9857 constant expressions. */
9861 /* When not -quiet, dump template instantiations other than functions, since
9862 announce_function will take care of those. */
9881 }
9883 /* We're done instantiating this template; return to the instantiation
9884 context. */
9886 void
9888 {
9889 /* Restore the filename and line number stashed away when we started
9890 this instantiation. */
9894 }
9896 /* We're instantiating a deferred template; restore the template
9897 instantiation context in which the instantiation was requested, which
9898 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9900 static tree
9902 {
9914 }
9916 /* Returns the TINST_LEVEL which gives the original instantiation
9917 context. */
9921 {
9927 }
9929 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9930 vector of template arguments, as for tsubst.
9932 Returns an appropriate tsubst'd friend declaration. */
9934 static tree
9936 {
9937 tree new_friend;
9942 /* This was a friend declared with an explicit template
9943 argument list, e.g.:
9945 friend void f<>(T);
9947 to indicate that f was a template instantiation, not a new
9948 function declaration. Now, we have to figure out what
9949 instantiation of what template. */
9950 {
9952 tree new_args;
9953 tree tmpl;
9956 /* Friend functions are looked up in the containing namespace scope.
9957 We must enter that scope, to avoid finding member functions of the
9958 current class with same name. */
9973 tsk_none);
9975 }
9979 /* The NEW_FRIEND will look like an instantiation, to the
9980 compiler, but is not an instantiation from the point of view of
9981 the language. For example, we might have had:
9983 template <class T> struct S {
9984 template <class U> friend void f(T, U);
9985 };
9987 Then, in S<int>, template <class U> void f(int, U) is not an
9988 instantiation of anything. */
9994 {
9998 }
10000 /* The mangled name for the NEW_FRIEND is incorrect. The function
10001 is not a template instantiation and should not be mangled like
10002 one. Therefore, we forget the mangling here; we'll recompute it
10003 later if we need it. */
10005 {
10008 }
10011 {
10012 tree old_decl;
10013 tree new_friend_template_info;
10014 tree new_friend_result_template_info;
10015 tree ns;
10018 /* We must save some information from NEW_FRIEND before calling
10019 duplicate decls since that function will free NEW_FRIEND if
10020 possible. */
10022 new_friend_is_defn =
10027 {
10028 /* This declaration is a `primary' template. */
10031 new_friend_result_template_info
10033 }
10034 else
10037 /* Inside pushdecl_namespace_level, we will push into the
10038 current namespace. However, the friend function should go
10039 into the namespace of the template. */
10049 {
10050 /* This new friend declaration matched an existing
10051 declaration. For example, given:
10053 template <class T> void f(T);
10054 template <class U> class C {
10055 template <class T> friend void f(T) {}
10056 };
10058 the friend declaration actually provides the definition
10059 of `f', once C has been instantiated for some type. So,
10060 old_decl will be the out-of-class template declaration,
10061 while new_friend is the in-class definition.
10063 But, if `f' was called before this point, the
10064 instantiation of `f' will have DECL_TI_ARGS corresponding
10065 to `T' but not to `U', references to which might appear
10066 in the definition of `f'. Previously, the most general
10067 template for an instantiation of `f' was the out-of-class
10068 version; now it is the in-class version. Therefore, we
10069 run through all specialization of `f', adding to their
10070 DECL_TI_ARGS appropriately. In particular, they need a
10071 new set of outer arguments, corresponding to the
10072 arguments for this class instantiation.
10074 The same situation can arise with something like this:
10076 friend void f(int);
10077 template <class T> class C {
10078 friend void f(T) {}
10079 };
10081 when `C<int>' is instantiated. Now, `f(int)' is defined
10082 in the class. */
10085 /* On the other hand, if the in-class declaration does
10086 *not* provide a definition, then we don't want to alter
10087 existing definitions. We can just leave everything
10088 alone. */
10089 ;
10090 else
10091 {
10095 /* Overwrite whatever template info was there before, if
10096 any, with the new template information pertaining to
10097 the declaration. */
10101 {
10102 /* We should have called reregister_specialization in
10103 duplicate_decls. */
10108 /* Instantiate it if the global has already been used. */
10112 }
10113 else
10114 {
10115 tree t;
10117 /* Indicate that the old function template is a partial
10118 instantiation. */
10126 /* Reassign any specializations already in the hash table
10127 to the new more general template, and add the
10128 additional template args. */
10132 {
10134 spec_entry elt;
10146 register_specialization
10149 }
10151 }
10152 }
10154 /* The information from NEW_FRIEND has been merged into OLD_DECL
10155 by duplicate_decls. */
10157 }
10158 }
10159 else
10160 {
10164 /* In the code
10165 template <class T> class C {
10166 template <class U> friend void C1<U>::f (); // case 1
10167 friend void C2<T>::f (); // case 2
10168 };
10169 we only need to make sure CONTEXT is a complete type for
10170 case 2. To distinguish between the two cases, we note that
10171 CONTEXT of case 1 remains dependent type after tsubst while
10172 this isn't true for case 2. */
10182 {
10184 /* do_friend adds the TEMPLATE_DECL for any member friend
10185 template even if it isn't a member template, i.e.
10186 template <class T> friend A<T>::f();
10187 Look through it in that case. */
10191 /* Check to see that the declaration is really present, and,
10192 possibly obtain an improved declaration. */
10197 }
10198 }
10201 }
10203 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10204 template arguments, as for tsubst.
10206 Returns an appropriate tsubst'd friend type or error_mark_node on
10207 failure. */
10209 static tree
10211 {
10212 tree tmpl;
10215 {
10218 }
10223 else
10231 {
10232 /* The friend template has already been declared. Just
10233 check to see that the declarations match, and install any new
10234 default parameters. We must tsubst the default parameters,
10235 of course. We only need the innermost template parameters
10236 because that is all that redeclare_class_template will look
10237 at. */
10240 {
10248 }
10249 }
10250 else
10251 {
10252 /* The friend template has not already been declared. In this
10253 case, the instantiation of the template class will cause the
10254 injection of this template into the namespace scope. */
10258 {
10259 /* The new TMPL is not an instantiation of anything, so we
10260 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10261 for the new type because that is supposed to be the
10262 corresponding template decl, i.e., TMPL. */
10269 /* It is hidden. */
10274 /* Inject this template into the enclosing namspace scope. */
10276 }
10277 }
10281 else
10285 }
10287 /* Returns zero if TYPE cannot be completed later due to circularity.
10288 Otherwise returns one. */
10290 static int
10292 {
10302 else
10304 }
10309 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10310 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10312 static tree
10315 {
10324 {
10331 clauses
10335 else
10337 }
10338 /* If the first attribute argument is an identifier, don't
10339 pass it through tsubst. Attributes like mode, format,
10340 cleanup and several target specific attributes expect it
10341 unmodified. */
10343 {
10344 tree chain
10349 }
10351 {
10352 /* An attribute pack expansion. */
10361 {
10365 }
10367 }
10368 else
10375 }
10377 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10378 unchanged or a new TREE_LIST chain. */
10380 static tree
10383 {
10388 {
10392 }
10396 {
10399 {
10402 {
10408 }
10409 }
10411 }
10414 }
10416 /* Apply any attributes which had to be deferred until instantiation
10417 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10418 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10420 static void
10423 {
10425 tree t;
10432 {
10436 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10437 to our attributes parameter. */
10439 }
10440 else
10441 {
10443 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10444 lookup_template_class_1, and should be preserved. */
10448 }
10452 {
10456 }
10460 {
10465 {
10468 {
10474 }
10475 else
10477 }
10480 }
10481 }
10483 /* Perform (or defer) access check for typedefs that were referenced
10484 from within the template TMPL code.
10485 This is a subroutine of instantiate_decl and instantiate_class_template.
10486 TMPL is the template to consider and TARGS is the list of arguments of
10487 that template. */
10489 static void
10491 {
10492 location_t saved_location;
10503 {
10515 /* Make access check error messages point to the location
10516 of the use of the typedef. */
10520 tf_warning_or_error);
10521 }
10523 }
10525 static tree
10527 {
10529 tree typedecl;
10530 tree pbinfo;
10531 tree base_list;
10533 tree fn_context;
10542 /* Figure out which template is being instantiated. */
10546 /* Mark the type as in the process of being defined. */
10549 /* Determine what specialization of the original template to
10550 instantiate. */
10555 {
10556 /* This TYPE is actually an instantiation of a partial
10557 specialization. We replace the innermost set of ARGS with
10558 the arguments appropriate for substitution. For example,
10559 given:
10561 template <class T> struct S {};
10562 template <class T> struct S<T*> {};
10564 and supposing that we are instantiating S<int*>, ARGS will
10565 presently be {int*} -- but we need {int}. */
10568 }
10569 else
10570 {
10573 }
10575 /* If the template we're instantiating is incomplete, then clearly
10576 there's nothing we can do. */
10578 {
10579 /* We can try again later. */
10582 }
10584 /* If we've recursively instantiated too many templates, stop. */
10588 /* We may be in the middle of deferred access check. Disable
10589 it now. */
10596 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10601 else
10602 {
10605 }
10606 /* Use #pragma pack from the template context. */
10612 /* Set the input location to the most specialized template definition.
10613 This is needed if tsubsting causes an error. */
10625 {
10628 /* Adjust visibility for template arguments. */
10630 }
10636 /* We should never instantiate a nested class before its enclosing
10637 class; we need to look up the nested class by name before we can
10638 instantiate it, and that lookup should instantiate the enclosing
10639 class. */
10645 {
10646 tree pbase_binfo;
10647 tree pushed_scope;
10650 /* We must enter the scope containing the type, as that is where
10651 the accessibility of types named in dependent bases are
10652 looked up from. */
10655 /* Substitute into each of the bases to determine the actual
10656 basetypes. */
10658 {
10659 tree base;
10665 {
10666 expanded_bases =
10673 }
10676 {
10678 /* Extract the already-expanded base class. */
10680 else
10681 /* Substitute to figure out the base class. */
10683 NULL_TREE);
10691 }
10692 }
10694 /* The list is now in reverse order; correct that. */
10699 }
10700 /* Now call xref_basetypes to set up all the base-class
10701 information. */
10709 /* Now that our base classes are set up, enter the scope of the
10710 class, so that name lookups into base classes, etc. will work
10711 correctly. This is precisely analogous to what we do in
10712 begin_class_definition when defining an ordinary non-template
10713 class, except we also need to push the enclosing classes. */
10716 /* Now members are processed in the order of declaration. */
10719 {
10723 {
10725 {
10727 /* A closure type for a lambda in an NSDMI or default argument.
10728 Ignore it; it will be regenerated when needed. */
10731 /* Build new CLASSTYPE_NESTED_UTDS. */
10733 tree newtag;
10739 /* If the member is a class template, then -- even after
10740 substitution -- there may be dependent types in the
10741 template argument list for the class. We increment
10742 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10743 that function will assume that no types are dependent
10744 when outside of a template. */
10754 {
10758 /* Unfortunately, lookup_template_class sets
10759 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10760 instantiation (i.e., for the type of a member
10761 template class nested within a template class.)
10762 This behavior is required for
10763 maybe_process_partial_specialization to work
10764 correctly, but is not accurate in this case;
10765 the TAG is not an instantiation of anything.
10766 (The corresponding TEMPLATE_DECL is an
10767 instantiation, but the TYPE is not.) */
10770 /* Now, we call pushtag to put this NEWTAG into the scope of
10771 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10772 pushtag calling push_template_decl. We don't have to do
10773 this for enums because it will already have been done in
10774 tsubst_enum. */
10778 }
10779 }
10781 {
10782 tree r;
10791 /* Instantiate members marked with attribute used. */
10797 }
10800 /* A closure type for a lambda in an NSDMI or default argument.
10802 else
10803 {
10804 /* Build new TYPE_FIELDS. */
10806 {
10807 tree condition;
10810 condition =
10820 }
10822 {
10823 tree r;
10827 /* The file and line for this declaration, to
10828 assist in error message reporting. Since we
10829 called push_tinst_level above, we don't need to
10830 restore these. */
10840 {
10841 /* A capture pack became multiple fields. */
10844 }
10847 {
10851 {
10852 /* In [temp.inst]:
10854 [t]he initialization (and any associated
10855 side-effects) of a static data member does
10856 not occur unless the static data member is
10857 itself used in a way that requires the
10858 definition of the static data member to
10859 exist.
10861 Therefore, we do not substitute into the
10862 initialized for the static data member here. */
10863 finish_static_data_member_decl
10869 /* Instantiate members marked with attribute used. */
10872 }
10874 {
10875 /* Determine whether R has a valid type and can be
10876 completed later. If R is invalid, then its type
10877 is replaced by error_mark_node. */
10883 {
10884 /* If R's type couldn't be completed and
10885 it isn't a flexible array member (whose
10886 type is incomplete by definition) give
10887 an error. */
10890 }
10891 }
10893 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10894 such a thing will already have been added to the field
10895 list by tsubst_enum in finish_member_declaration in the
10896 CLASSTYPE_NESTED_UTDS case above. */
10900 {
10903 }
10904 }
10905 }
10906 }
10907 }
10908 else
10909 {
10912 {
10913 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10919 {
10920 /* template <class T> friend class C; */
10923 }
10925 {
10926 /* template <class T> friend class C::D; */
10932 }
10935 {
10936 /* This could be either
10938 friend class T::C;
10940 when dependent_type_p is false or
10942 template <class U> friend class T::C;
10944 otherwise. */
10945 /* Bump processing_template_decl in case this is something like
10946 template <class T> friend struct A<T>::B. */
10953 }
10957 {
10958 /* friend class C;
10960 where C hasn't been declared yet. Let's lookup name
10961 from namespace scope directly, bypassing any name that
10962 come from dependent base class. */
10965 /* The call to xref_tag_from_type does injection for friend
10966 classes. */
10968 friend_type =
10972 }
10974 /* friend class C<T>; */
10977 /* Otherwise it's
10979 friend class C;
10981 where C is already declared or
10983 friend class C<int>;
10985 We don't have to do anything in these cases. */
10988 /* Trick make_friend_class into realizing that the friend
10989 we're adding is a template, not an ordinary class. It's
10990 important that we use make_friend_class since it will
10991 perform some error-checking and output cross-reference
10992 information. */
11000 }
11001 else
11002 {
11003 /* Build new DECL_FRIENDLIST. */
11004 tree r;
11006 /* The file and line for this declaration, to
11007 assist in error message reporting. Since we
11008 called push_tinst_level above, we don't need to
11009 restore these. */
11013 {
11016 }
11021 {
11024 }
11025 }
11026 }
11027 }
11030 {
11031 /* Restore these before substituting into the lambda capture
11032 initializers. */
11035 }
11037 /* Set the file and line number information to whatever is given for
11038 the class itself. This puts error messages involving generated
11039 implicit functions at a predictable point, and the same point
11040 that would be used for non-template classes. */
11047 /* We don't instantiate default arguments for member functions. 14.7.1:
11049 The implicit instantiation of a class template specialization causes
11050 the implicit instantiation of the declarations, but not of the
11051 definitions or default arguments, of the class member functions,
11052 member classes, static data members and member templates.... */
11054 /* Some typedefs referenced from within the template code need to be access
11055 checked at template instantiation time, i.e now. These types were
11056 added to the template at parsing time. Let's get those and perform
11057 the access checks then. */
11067 /* The vtable for a template class can be emitted in any translation
11068 unit in which the class is instantiated. When there is no key
11069 method, however, finish_struct_1 will already have added TYPE to
11070 the keyed_classes. */
11075 }
11077 /* Wrapper for instantiate_class_template_1. */
11079 tree
11081 {
11082 tree ret;
11087 }
11089 static tree
11091 {
11092 tree r;
11098 else
11099 {
11106 }
11108 }
11110 /* Given a function parameter pack TMPL_PARM and some function parameters
11111 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11112 and set *SPEC_P to point at the next point in the list. */
11114 tree
11116 {
11117 /* Collect all of the extra "packed" parameters into an
11118 argument pack. */
11119 tree parmvec;
11129 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11133 {
11138 }
11140 /* Build the argument packs. */
11145 }
11147 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11148 NONTYPE_ARGUMENT_PACK. */
11150 static tree
11152 {
11154 }
11156 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11157 pack expansion with no extra args, 2 if it has extra args, or 0
11158 if it is not a pack expansion. */
11160 static int
11162 {
11168 /* A decl pack is itself an expansion. */
11175 }
11178 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11180 static tree
11182 {
11189 }
11191 /* This is a subroutine of tsubst_pack_expansion.
11193 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11194 mechanism to store the (non complete list of) arguments of the
11195 substitution and return a non substituted pack expansion, in order
11196 to wait for when we have enough arguments to really perform the
11197 substitution. */
11199 static bool
11203 {
11204 /* If one pack has an expansion and another pack has a normal
11205 argument or if one pack has an empty argument and an another
11206 one hasn't then tsubst_pack_expansion cannot perform the
11207 substitution and need to fall back on the
11208 PACK_EXPANSION_EXTRA mechanism. */
11216 {
11219 parm_pack;
11221 {
11226 /* We can't substitute a pack expansion with extra args into
11227 our pattern. */
11231 else
11233 }
11237 }
11239 }
11241 /* [temp.variadic]/6 says that:
11243 The instantiation of a pack expansion [...]
11244 produces a list E1,E2, ..., En, where N is the number of elements
11245 in the pack expansion parameters.
11247 This subroutine of tsubst_pack_expansion produces one of these Ei.
11249 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11250 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11251 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11252 INDEX is the index 'i' of the element Ei to produce. ARGS,
11253 COMPLAIN, and IN_DECL are the same parameters as for the
11254 tsubst_pack_expansion function.
11256 The function returns the resulting Ei upon successful completion,
11257 or error_mark_node.
11259 Note that this function possibly modifies the ARGS parameter, so
11260 it's the responsibility of the caller to restore it. */
11262 static tree
11264 tree parm_packs,
11266 tree args /* This parm gets
11268 tsubst_flags_t complain,
11269 tree in_decl)
11270 {
11271 tree t;
11274 /* For each parameter pack, change the substitution of the parameter
11275 pack to the ith argument in its argument pack, then expand the
11276 pattern. */
11278 {
11283 ith_elem_is_expansion |=
11286 /* Select the Ith argument from the pack. */
11290 {
11292 {
11297 }
11298 else
11300 }
11301 else
11302 {
11307 {
11309 /* Update the corresponding argument. */
11311 }
11312 else
11313 /* Re-use the ARGUMENT_PACK_SELECT. */
11315 }
11317 }
11319 /* Substitute into the PATTERN with the (possibly altered)
11320 arguments. */
11322 /* Expanding a fixed parameter pack from
11323 coerce_template_parameter_pack. */
11328 {
11331 else
11334 }
11338 else
11341 /* If the Ith argument pack element is a pack expansion, then
11342 the Ith element resulting from the substituting is going to
11343 be a pack expansion as well. */
11348 }
11350 /* When the unexpanded parameter pack in a fold expression expands to an empty
11351 sequence, the value of the expression is as follows; the program is
11352 ill-formed if the operator is not listed in this table.
11354 && true
11355 || false
11356 , void() */
11358 tree
11360 {
11364 {
11373 }
11379 }
11381 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11382 form an expression that combines the two terms using the
11383 operator of T. */
11385 static tree
11387 {
11391 // Handle compound assignment operators.
11396 {
11406 complain);
11407 }
11408 }
11410 /* Substitute ARGS into the pack of a fold expression T. */
11414 {
11416 }
11418 /* Substitute ARGS into the pack of a fold expression T. */
11422 {
11424 }
11426 /* Expand a PACK of arguments into a grouped as left fold.
11427 Given a pack containing elements A0, A1, ..., An and an
11428 operator @, this builds the expression:
11430 ((A0 @ A1) @ A2) ... @ An
11432 Note that PACK must not be empty.
11434 The operator is defined by the original fold expression T. */
11436 static tree
11438 {
11441 {
11444 }
11446 }
11448 /* Substitute into a unary left fold expression. */
11450 static tree
11452 tree in_decl)
11453 {
11458 {
11462 }
11465 else
11467 }
11469 /* Substitute into a binary left fold expression.
11471 Do ths by building a single (non-empty) vector of argumnts and
11472 building the expression from those elements. */
11474 static tree
11476 tree in_decl)
11477 {
11486 {
11491 }
11499 }
11501 /* Expand a PACK of arguments into a grouped as right fold.
11502 Given a pack containing elementns A0, A1, ..., and an
11503 operator @, this builds the expression:
11505 A0@ ... (An-2 @ (An-1 @ An))
11507 Note that PACK must not be empty.
11509 The operator is defined by the original fold expression T. */
11511 tree
11513 {
11514 // Build the expression.
11518 {
11521 }
11523 }
11525 /* Substitute into a unary right fold expression. */
11527 static tree
11529 tree in_decl)
11530 {
11535 {
11539 }
11542 else
11544 }
11546 /* Substitute into a binary right fold expression.
11548 Do ths by building a single (non-empty) vector of arguments and
11549 building the expression from those elements. */
11551 static tree
11553 tree in_decl)
11554 {
11563 {
11568 }
11577 }
11579 /* Walk through the pattern of a pack expansion, adding everything in
11580 local_specializations to a list. */
11582 struct el_data
11583 {
11584 tree extra;
11585 tsubst_flags_t complain;
11586 };
11587 static tree
11589 {
11594 {
11596 {
11597 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11600 {
11606 }
11608 {
11609 /* Handle lambda capture here, since we aren't doing any
11610 substitution now, and so tsubst_copy won't call
11611 process_outer_var_ref. */
11615 {
11621 {
11622 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11623 proxies. */
11625 {
11630 }
11632 }
11633 }
11634 }
11635 }
11639 }
11641 }
11642 static tree
11644 {
11648 }
11650 /* Substitute ARGS into T, which is an pack expansion
11651 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11652 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11653 (if only a partial substitution could be performed) or
11654 ERROR_MARK_NODE if there was an error. */
11655 tree
11657 tree in_decl)
11658 {
11659 tree pattern;
11664 tree result;
11672 /* Add in any args remembered from an earlier partial instantiation. */
11675 {
11677 {
11678 /* The partial instantiation involved local declarations collected in
11679 extract_local_specs; map from the general template to our local
11680 context. */
11686 /* else inst is already a full instantiation of the pack. */
11688 }
11691 }
11696 /* Determine the argument packs that will instantiate the parameter
11697 packs used in the expansion expression. While we're at it,
11698 compute the number of arguments to be expanded and make sure it
11699 is consistent. */
11702 {
11709 {
11714 else
11717 }
11719 {
11720 /* ??? Support use in other patterns. */
11724 }
11726 {
11727 /* We know we have correct local_specializations if this
11728 expansion is at function scope, or if we're dealing with a
11729 local parameter in a requires expression; for the latter,
11730 tsubst_requires_expr set it up appropriately. */
11733 else
11734 /* We can't rely on local_specializations for a parameter
11735 name used later in a function declaration (such as in a
11736 late-specified return type). Even if it exists, it might
11737 have the wrong value for a recursive call. */
11741 {
11742 /* This parameter pack was used in an unevaluated context. Just
11743 make a dummy decl, since it's only used for its type. */
11748 /* Partial instantiation of the parm_pack, we can't build
11749 up an argument pack yet. */
11751 else
11753 }
11755 /* This argument pack isn't fully instantiated yet. We set this
11756 flag rather than clear arg_pack because we do want to do the
11757 optimization below, and we don't want to substitute directly
11758 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11759 where it isn't expected). */
11761 }
11763 {
11767 }
11768 else
11769 {
11775 }
11782 /* This can only happen if we forget to expand an argument
11783 pack somewhere else. Just return an error, silently. */
11784 {
11788 }
11791 {
11795 /* Don't bother trying to do a partial substitution with
11796 incomplete packs; we'll try again after deduction. */
11804 {
11809 pattern);
11810 else
11812 pattern);
11814 }
11816 /* Keep track of the parameter packs and their corresponding
11817 argument packs. */
11820 }
11821 else
11822 {
11823 /* We can't substitute for this parameter pack. We use a flag as
11824 well as the missing_level counter because function parameter
11825 packs don't have a level. */
11828 }
11829 }
11831 /* If the expansion is just T..., return the matching argument pack, unless
11832 we need to call convert_from_reference on all the elements. This is an
11833 important optimization; see c++/68422. */
11836 {
11839 /* If the argument pack is a single pack expansion, pull it out. */
11844 /* Types need no adjustment, nor does sizeof..., and if we still have
11845 some pack expansion args we won't do anything yet. */
11850 /* Also optimize expression pack expansions if we can tell that the
11851 elements won't have reference type. */
11857 /* Otherwise use the normal path so we get convert_from_reference. */
11858 }
11860 /* We cannot expand this expansion expression, because we don't have
11861 all of the argument packs we need. */
11863 {
11864 /* We got some full packs, but we can't substitute them in until we
11865 have values for all the packs. So remember these until then. */
11874 }
11876 {
11877 /* There were no real arguments, we're just replacing a parameter
11878 pack with another version of itself. Substitute into the
11879 pattern and return a PACK_EXPANSION_*. The caller will need to
11880 deal with that. */
11884 else
11888 }
11893 {
11894 /* We're in a late-specified return type, so create our own local
11895 specializations map; the current map is either NULL or (in the
11896 case of recursive unification) might have bindings that we don't
11897 want to use or alter. */
11900 }
11902 /* For each argument in each argument pack, substitute into the
11903 pattern. */
11907 {
11909 i,
11911 in_decl);
11914 {
11917 }
11918 }
11920 /* Update ARGS to restore the substitution from parameter packs to
11921 their argument packs. */
11923 {
11930 else
11931 {
11939 /* Update the corresponding argument. */
11943 else
11945 }
11946 }
11949 {
11952 }
11954 /* If the dependent pack arguments were such that we end up with only a
11955 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11961 }
11963 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11964 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11965 parameter packs; all parms generated from a function parameter pack will
11966 have the same DECL_PARM_INDEX. */
11968 tree
11970 {
11972 tree patparm;
11975 {
11981 }
11982 else
11983 {
11988 }
11991 }
11993 /* Make an argument pack out of the TREE_VEC VEC. */
11995 static tree
11997 {
11998 tree pack;
12002 else
12003 {
12006 }
12009 }
12011 /* Return an exact copy of template args T that can be modified
12012 independently. */
12014 static tree
12016 {
12024 {
12029 }
12035 }
12037 /* Substitute ARGS into the vector or list of template arguments T. */
12039 static tree
12041 {
12053 {
12055 tree new_arg;
12060 {
12061 /* Substitute into an expansion expression. */
12065 /* Add to the expanded length adjustment the number of
12066 expanded arguments. We subtract one from this
12067 measurement, because the argument pack expression
12068 itself is already counted as 1 in
12069 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12070 the argument pack is empty. */
12072 }
12074 {
12075 /* Substitute into each of the arguments. */
12084 else
12089 }
12090 else
12099 }
12104 /* Make space for the expanded arguments coming from template
12105 argument packs. */
12107 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12108 arguments for a member template.
12109 In that case each TREE_VEC in ORIG_T represents a level of template
12110 arguments, and ORIG_T won't carry any non defaulted argument count.
12111 It will rather be the nested TREE_VECs that will carry one.
12112 In other words, ORIG_T carries a non defaulted argument count only
12113 if it doesn't contain any nested TREE_VEC. */
12115 {
12119 }
12121 {
12125 {
12128 /* Now expand the template argument pack "in place". */
12131 }
12132 else
12133 {
12135 out++;
12136 }
12137 }
12140 }
12142 /* Substitute ARGS into one level PARMS of template parameters. */
12144 static tree
12146 {
12153 {
12161 }
12164 }
12166 /* Return the result of substituting ARGS into the template parameters
12167 given by PARMS. If there are m levels of ARGS and m + n levels of
12168 PARMS, then the result will contain n levels of PARMS. For
12169 example, if PARMS is `template <class T> template <class U>
12170 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12171 result will be `template <int*, double, class V>'. */
12173 static tree
12175 {
12179 /* When substituting into a template, we must set
12180 PROCESSING_TEMPLATE_DECL as the template parameters may be
12181 dependent if they are based on one-another, and the dependency
12182 predicates are short-circuit outside of templates. */
12189 {
12196 }
12201 }
12203 /* Return the result of substituting ARGS into one template parameter
12204 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12205 parameter and which TREE_PURPOSE is the default argument of the
12206 template parameter. */
12208 static tree
12210 {
12231 }
12233 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12234 type T. If T is not an aggregate or enumeration type, it is
12235 handled as if by tsubst. IN_DECL is as for tsubst. If
12236 ENTERING_SCOPE is nonzero, T is the context for a template which
12237 we are presently tsubst'ing. Return the substituted value. */
12239 static tree
12241 tree args,
12242 tsubst_flags_t complain,
12243 tree in_decl,
12245 {
12250 {
12255 /* Fall through. */
12259 {
12260 tree argvec;
12261 tree context;
12262 tree r;
12266 /* In "sizeof(X<I>)" we need to evaluate "I". */
12272 /* First, determine the context for the type we are looking
12273 up. */
12276 {
12279 /* If context is a nested class inside a class template,
12280 it may still need to be instantiated (c++/33959). */
12282 }
12284 /* Then, figure out what arguments are appropriate for the
12285 type we are trying to find. For example, given:
12287 template <class T> struct S;
12288 template <class T, class U> void f(T, U) { S<U> su; }
12290 and supposing that we are instantiating f<int, double>,
12291 then our ARGS will be {int, double}, but, when looking up
12292 S we only want {double}. */
12297 else
12298 {
12302 }
12308 }
12309 else
12310 /* This is not a template type, so there's nothing to do. */
12315 }
12316 }
12320 /* Substitute into the default argument ARG (a default argument for
12321 FN), which has the indicated TYPE. */
12323 tree
12325 tsubst_flags_t complain)
12326 {
12331 /* This can happen in invalid code. */
12349 /* This default argument came from a template. Instantiate the
12350 default argument here, not in tsubst. In the case of
12351 something like:
12353 template <class T>
12354 struct S {
12355 static T t();
12356 void f(T = t());
12357 };
12359 we must be careful to do name lookup in the scope of S<T>,
12360 rather than in the current class. */
12362 /* The "this" pointer is not valid in a default argument. */
12364 {
12369 }
12374 /* The default argument expression may cause implicitly defined
12375 member functions to be synthesized, which will result in garbage
12376 collection. We must treat this situation as if we were within
12377 the body of function so as to avoid collecting live data on the
12378 stack. */
12388 /* Restore the "this" pointer. */
12390 {
12393 }
12400 /* Make sure the default argument is reasonable. */
12406 {
12410 }
12413 }
12415 /* Substitute into all the default arguments for FN. */
12417 static void
12419 {
12420 tree arg;
12421 tree tmpl_args;
12425 /* If this function is not yet instantiated, we certainly don't need
12426 its default arguments. */
12429 /* Don't do this again for clones. */
12435 arg;
12441 complain);
12442 }
12444 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12446 static tree
12448 tree lambda_fntype)
12449 {
12454 /* Nobody should be tsubst'ing into non-template functions. */
12458 {
12459 /* If T is not dependent, just return it. */
12463 /* Calculate the most general template of which R is a
12464 specialization. */
12467 /* We're substituting a lambda function under tsubst_lambda_expr but not
12468 directly from it; find the matching function we're already inside.
12469 But don't do this if T is a generic lambda with a single level of
12470 template parms, as in that case we're doing a normal instantiation. */
12476 /* Calculate the complete set of arguments used to
12477 specialize R. */
12479 (DECL_TEMPLATE_RESULT
12485 /* Check to see if we already have this specialization. */
12487 {
12491 }
12493 /* We can see more levels of arguments than parameters if
12494 there was a specialization of a member template, like
12495 this:
12497 template <class T> struct S { template <class U> void f(); }
12498 template <> template <class U> void S<int>::f(U);
12500 Here, we'll be substituting into the specialization,
12501 because that's where we can find the code we actually
12502 want to generate, but we'll have enough arguments for
12503 the most general template.
12505 We also deal with the peculiar case:
12507 template <class T> struct S {
12508 template <class U> friend void f();
12509 };
12510 template <class U> void f() {}
12511 template S<int>;
12512 template void f<double>();
12514 Here, the ARGS for the instantiation of will be {int,
12515 double}. But, we only need as many ARGS as there are
12516 levels of template parameters in CODE_PATTERN. We are
12517 careful not to get fooled into reducing the ARGS in
12518 situations like:
12520 template <class T> struct S { template <class U> void f(U); }
12521 template <class T> template <> void S<T>::f(int) {}
12523 which we can spot because the pattern will be a
12524 specialization in this case. */
12531 }
12532 else
12533 {
12534 /* This special case arises when we have something like this:
12536 template <class T> struct S {
12537 friend void f<int>(int, double);
12538 };
12540 Here, the DECL_TI_TEMPLATE for the friend declaration
12541 will be an IDENTIFIER_NODE. We are being called from
12542 tsubst_friend_function, and we want only to create a
12543 new decl (R) with appropriate types so that we can call
12544 determine_specialization. */
12547 }
12564 /* If we hit excessive deduction depth, the type is bogus even if
12565 it isn't error_mark_node, so don't build a decl. */
12569 /* We do NOT check for matching decls pushed separately at this
12570 point, as they may not represent instantiations of this
12571 template, and in any case are considered separate under the
12572 discrete model. */
12576 /* Clear out the mangled name and RTL for the instantiation. */
12579 /* Leave DECL_INITIAL set on deleted instantiations. */
12584 /* OpenMP UDRs have the only argument a reference to the declared
12585 type. We want to diagnose if the declared type is a reference,
12586 which is invalid, but as references to references are usually
12587 quietly merged, diagnose it here. */
12589 {
12590 tree argtype
12595 "reference type %qT in "
12599 argtype);
12600 }
12603 /* Type-conversion operator. Reconstruct the name, in
12604 case it's the name of one of the template's parameters. */
12614 {
12618 }
12625 /* If this is an instantiation of a function with internal
12626 linkage, we already know what object file linkage will be
12627 assigned to the instantiation. */
12636 /* We'll re-clone as appropriate in instantiate_template. */
12639 /* If we aren't complaining now, return on error before we register
12640 the specialization so that we'll complain eventually. */
12646 /* When instantiating a constrained member, substitute
12647 into the constraints to create a new constraint. */
12650 {
12653 }
12655 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12656 this in the special friend case mentioned above where
12657 GEN_TMPL is NULL. */
12659 {
12664 tree new_r
12667 /* We instantiated this while substituting into
12668 the type earlier (template/friend54.C). */
12671 /* We're not supposed to instantiate default arguments
12672 until they are called, for a template. But, for a
12673 declaration like:
12675 template <class T> void f ()
12676 { extern void g(int i = T()); }
12678 we should do the substitution when the template is
12679 instantiated. We handle the member function case in
12680 instantiate_class_template since the default arguments
12681 might refer to other members of the class. */
12686 }
12687 else
12690 /* Copy the list of befriending classes. */
12694 {
12698 }
12701 {
12705 /* If this is an instantiation of a member template, clone it.
12706 If it isn't, that'll be handled by
12707 clone_constructors_and_destructors. */
12710 }
12721 /* Possibly limit visibility based on template args. */
12724 {
12728 }
12737 }
12739 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12741 static tree
12743 tree lambda_fntype)
12744 {
12745 /* We can get here when processing a member function template,
12746 member class template, or template template parameter. */
12749 tree spec;
12750 tree tmpl_args;
12751 tree full_args;
12752 tree r;
12756 {
12757 /* Template template parameter is treated here. */
12761 /* If we get a real template back, return it. This can happen in
12762 the context of most_specialized_partial_spec. */
12765 else
12766 /* The new TEMPLATE_DECL was built in
12767 reduce_template_parm_level. */
12770 }
12773 {
12774 /* We might already have an instance of this template.
12775 The ARGS are for the surrounding class type, so the
12776 full args contain the tsubst'd args for the context,
12777 plus the innermost args from the template decl. */
12781 /* Because this is a template, the arguments will still be
12782 dependent, even after substitution. If
12783 PROCESSING_TEMPLATE_DECL is not set, the dependency
12784 predicates will short-circuit. */
12792 /* If this is a default template template argument,
12793 tsubst might not have changed anything. */
12801 }
12803 /* Make a new template decl. It will be similar to the
12804 original, but will record the current template arguments.
12805 We also create a new function declaration, which is just
12806 like the old one, but points to this new template, rather
12807 than the old one. */
12812 // Build new template info linking to the original template decl.
12814 {
12817 }
12818 else
12821 /* The template parameters for this new template are all the
12822 template parameters for the old template, except the
12823 outermost level of parameters. */
12826 complain);
12830 {
12831 tree new_type;
12839 /* For a partial specialization, we need to keep pointing to
12840 the primary template. */
12846 }
12847 else
12848 {
12849 tree new_decl;
12853 else
12863 {
12866 }
12867 else
12868 {
12871 }
12872 }
12882 /* Record this non-type partial instantiation. */
12888 }
12890 /* True if FN is the op() for a lambda in an uninstantiated template. */
12892 bool
12894 {
12899 }
12901 /* We're instantiating a variable from template function TCTX. Return the
12902 corresponding current enclosing scope. This gets complicated because lambda
12903 functions in templates are regenerated rather than instantiated, but generic
12904 lambda functions are subsequently instantiated. */
12906 static tree
12908 {
12917 {
12930 }
12932 }
12934 /* Substitute the ARGS into the T, which is a _DECL. Return the
12935 result of the substitution. Issue error and warning messages under
12936 control of COMPLAIN. */
12938 static tree
12940 {
12941 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12942 location_t saved_loc;
12947 /* Set the filename and linenumber to improve error-reporting. */
12952 {
12962 {
12970 {
12971 /* If there is a local specialization that isn't a
12972 parameter pack, it means that we're doing a "simple"
12973 substitution from inside tsubst_pack_expansion. Just
12974 return the local specialization (which will be a single
12975 parm). */
12982 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12983 the parameters in this function parameter pack. */
12987 {
12990 /* Zero-length parameter packs are boring. Just substitute
12991 into the chain. */
12995 }
12996 else
12997 {
12998 /* All we did was update the type. Make a note of that. */
13001 }
13002 }
13004 /* Loop through all of the parameters we'll build. When T is
13005 a function parameter pack, LEN is the number of expanded
13006 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13009 {
13016 /* We're on the Ith parameter of the function parameter
13017 pack. */
13018 {
13019 /* Get the Ith type. */
13022 /* Rename the parameter to include the index. */
13025 }
13027 /* We're dealing with a normal parameter. */
13035 {
13038 else
13041 }
13051 /* Keep track of the first new parameter we
13052 generate. That's what will be returned to the
13053 caller. */
13057 /* Build a proper chain of parameters when substituting
13058 into a function parameter pack. */
13061 }
13063 /* If cp_unevaluated_operand is set, we're just looking for a
13064 single dummy parameter, so don't keep going. */
13069 /* FIRST_R contains the start of the chain we've built. */
13071 }
13075 {
13082 {
13083 /* This field is a lambda capture pack. Return a TREE_VEC of
13084 the expanded fields to instantiate_class_template_1. */
13088 {
13091 }
13092 else
13093 {
13094 /* All we did was update the type. Make a note of that. */
13097 }
13098 }
13101 {
13104 {
13108 }
13118 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13119 number of bits. */
13125 {
13126 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13127 NSDMI in perform_member_init. Still set DECL_INITIAL
13128 so that we know there is one. */
13133 }
13134 /* We don't have to set DECL_CONTEXT here; it is set by
13135 finish_member_declaration. */
13143 }
13147 }
13151 /* We reach here only for member using decls. We also need to check
13152 uses_template_parms because DECL_DEPENDENT_P is not set for a
13153 using-declaration that designates a member of the current
13154 instantiation (c++/53549). */
13157 {
13161 {
13166 {
13170 {
13173 }
13174 else
13175 {
13178 }
13180 }
13181 }
13182 else
13183 {
13189 else
13190 {
13193 }
13194 }
13195 }
13196 else
13197 {
13200 }
13205 {
13208 tree spec;
13210 tree ctx;
13219 {
13220 /* If this is the canonical decl, we don't have to
13221 mess with instantiations, and often we can't (for
13222 typename, template type parms and such). Note that
13223 TYPE_NAME is not correct for the above test if
13224 we've copied the type for a typedef. */
13230 }
13232 /* Check to see if we already have the specialization we
13233 need. */
13236 {
13237 /* T is a static data member or namespace-scope entity.
13238 We have to substitute into namespace-scope variables
13239 (not just variable templates) because of cases like:
13241 template <class T> void f() { extern T t; }
13243 where the entity referenced is not known until
13244 instantiation time. */
13248 {
13250 complain,
13252 /* If CTX is unchanged, then T is in fact the
13253 specialization we want. That situation occurs when
13254 referencing a static data member within in its own
13255 class. We can use pointer equality, rather than
13256 same_type_p, because DECL_CONTEXT is always
13257 canonical... */
13259 /* ... unless T is a member template; in which
13260 case our caller can be willing to create a
13261 specialization of that template represented
13262 by T. */
13266 }
13269 {
13274 argvec = (coerce_innermost_template_parms
13282 }
13283 }
13284 else
13285 {
13286 /* A local variable. */
13288 /* Subsequent calls to pushdecl will fill this in. */
13290 /* Unless this is a reference to a static variable from an
13291 enclosing function, in which case we need to fill it in now. */
13293 {
13297 }
13299 }
13300 /* If we already have the specialization we need, there is
13301 nothing more to do. */
13303 {
13306 }
13308 /* Create a new node for the specialization we need. */
13311 {
13314 else
13322 {
13323 /* Mask off any template args past the variable's context so we
13324 don't replace the auto with an unrelated argument. */
13328 /* This should never happen with the new lambda instantiation
13329 model, but keep the handling just in case. */
13332 }
13334 }
13336 {
13337 /* Even if the original location is out of scope, the
13338 newly substituted one is not. */
13345 {
13346 /* It may seem that this case cannot occur, since:
13348 typedef void f();
13349 void g() { f x; }
13351 declares a function, not a variable. However:
13353 typedef void f();
13354 template <typename T> void g() { T t; }
13355 template void g<f>();
13357 is an attempt to declare a variable with function
13358 type. */
13360 /* R is not yet sufficiently initialized, so we
13361 just use its name. */
13364 }
13366 /* Wait until cp_finish_decl to set this again, to handle
13367 circular dependency (template/instantiate6.C). */
13372 {
13377 {
13380 }
13382 }
13386 }
13392 /* Clear out the mangled name and RTL for the instantiation. */
13396 /* The initializer must not be expanded until it is required;
13397 see [temp.inst]. */
13401 {
13407 /* Possibly limit visibility based on template args. */
13410 {
13414 }
13416 }
13419 {
13420 /* A static data member declaration is always marked
13421 external when it is declared in-class, even if an
13422 initializer is present. We mimic the non-template
13423 processing here. */
13431 }
13432 else
13433 {
13438 }
13446 /* Preserve a typedef that names a type. */
13448 {
13452 /* An alias template specialization can be dependent
13453 even if its underlying type is not. */
13455 }
13458 }
13463 }
13464 #undef RETURN
13466 out:
13467 /* Restore the file and line information. */
13471 }
13473 /* Substitute into the ARG_TYPES of a function type.
13474 If END is a TREE_CHAIN, leave it and any following types
13475 un-substituted. */
13477 static tree
13479 tree args,
13480 tree end,
13481 tsubst_flags_t complain,
13482 tree in_decl)
13483 {
13484 tree remaining_arg_types;
13488 tree default_arg;
13499 {
13500 /* For a pack expansion, perform substitution on the
13501 entire expression. Later on, we'll handle the arguments
13502 one-by-one. */
13507 /* So that we'll spin through the parameters, one by one. */
13509 else
13510 {
13511 /* We only partially substituted into the parameter
13512 pack. Our type is TYPE_PACK_EXPANSION. */
13515 }
13516 }
13529 {
13531 {
13535 }
13537 }
13538 /* DR 657. */
13542 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13543 top-level qualifiers as required. */
13546 /* We do not substitute into default arguments here. The standard
13547 mandates that they be instantiated only when needed, which is
13548 done in build_over_call. */
13551 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13552 since the new op() won't have any associated template arguments for us
13553 to refer to later. */
13559 {
13560 /* We've instantiated a template before its default arguments
13561 have been parsed. This can happen for a nested template
13562 class, and is not an error unless we require the default
13563 argument in a call of this function. */
13564 remaining_arg_types =
13567 }
13568 else
13569 remaining_arg_types =
13571 }
13574 }
13576 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13577 *not* handle the exception-specification for FNTYPE, because the
13578 initial substitution of explicitly provided template parameters
13579 during argument deduction forbids substitution into the
13580 exception-specification:
13582 [temp.deduct]
13584 All references in the function type of the function template to the
13585 corresponding template parameters are replaced by the specified tem-
13586 plate argument values. If a substitution in a template parameter or
13587 in the function type of the function template results in an invalid
13588 type, type deduction fails. [Note: The equivalent substitution in
13589 exception specifications is done only when the function is instanti-
13590 ated, at which point a program is ill-formed if the substitution
13591 results in an invalid type.] */
13593 static tree
13595 tree args,
13596 tsubst_flags_t complain,
13597 tree in_decl)
13598 {
13599 tree return_type;
13601 tree fntype;
13603 /* The TYPE_CONTEXT is not used for function/method types. */
13606 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13607 failure. */
13611 {
13612 /* Substitute the argument types. */
13624 {
13625 /* DR 1207: 'this' is in scope in the trailing return type. */
13627 }
13629 /* Substitute the return type. */
13633 {
13636 }
13637 }
13638 else
13639 /* Substitute the return type. */
13644 /* DR 486 clarifies that creation of a function type with an
13645 invalid return type is a deduction failure. */
13648 {
13650 {
13653 else
13655 }
13657 }
13658 /* And DR 657. */
13663 {
13664 /* Substitute the argument types. */
13669 }
13671 /* Construct a new type node and return it. */
13673 {
13678 }
13679 else
13680 {
13682 /* Don't pick up extra function qualifiers from the basetype. */
13685 {
13686 /* [temp.deduct]
13688 Type deduction may fail for any of the following
13689 reasons:
13691 -- Attempting to create "pointer to member of T" when T
13692 is not a class type. */
13695 r);
13697 }
13702 }
13709 }
13711 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13712 ARGS into that specification, and return the substituted
13713 specification. If there is no specification, return NULL_TREE. */
13715 static tree
13717 tree args,
13718 tsubst_flags_t complain,
13719 tree in_decl,
13721 {
13722 tree specs;
13723 tree new_specs;
13728 {
13729 /* A noexcept-specifier. */
13734 {
13735 /* Defer instantiation of noexcept-specifiers to avoid
13736 excessive instantiations (c++/49107). */
13739 {
13740 /* We already partially instantiated this member template,
13741 so combine the new args with the old. */
13746 }
13747 else
13748 {
13751 }
13752 }
13753 else
13754 new_specs = tsubst_copy_and_build
13758 }
13760 {
13763 else
13765 {
13766 tree spec;
13771 {
13772 /* Expand the pack expansion type. */
13775 in_decl);
13781 else
13782 {
13783 /* We're substituting into a member template, so
13784 we got a TYPE_PACK_EXPANSION back. Add that
13785 expansion and move on. */
13789 expanded_specs,
13790 complain);
13793 }
13794 }
13797 {
13800 else
13805 complain);
13806 }
13809 }
13810 }
13812 }
13814 /* Take the tree structure T and replace template parameters used
13815 therein with the argument vector ARGS. IN_DECL is an associated
13816 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13817 Issue error and warning messages under control of COMPLAIN. Note
13818 that we must be relatively non-tolerant of extensions here, in
13819 order to preserve conformance; if we allow substitutions that
13820 should not be allowed, we may allow argument deductions that should
13821 not succeed, and therefore report ambiguous overload situations
13822 where there are none. In theory, we could allow the substitution,
13823 but indicate that it should have failed, and allow our caller to
13824 make sure that the right thing happens, but we don't try to do this
13825 yet.
13827 This function is used for dealing with types, decls and the like;
13828 for expressions, use tsubst_expr or tsubst_copy. */
13830 tree
13832 {
13855 else
13860 /* Reuse typedefs. We need to do this to handle dependent attributes,
13861 such as attribute aligned. */
13864 {
13868 {
13869 /* DECL represents an alias template and we want to
13870 instantiate it. */
13874 }
13878 {
13882 }
13887 else
13888 /* The typedef is from a non-template context. */
13892 {
13894 r = cp_build_qualified_type_real
13898 }
13899 else
13900 {
13901 /* We don't have an instantiation yet, so drop the typedef. */
13906 }
13907 }
13924 {
13950 {
13956 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13957 needed. */
13963 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13964 with TREE_SIDE_EFFECTS that indicates this is not an integral
13965 constant expression. */
13968 {
13971 }
13974 }
13980 {
13986 /* Early in template argument deduction substitution, we don't
13987 want to reduce the level of 'auto', or it will be confused
13988 with a normal template parm in subsequent deduction. */
14000 {
14003 /* See through ARGUMENT_PACK_SELECT arguments. */
14006 }
14011 {
14013 /* If ARG is an argument pack, we don't actually want to
14014 perform a substitution here, because substitutions
14015 for argument packs are only done
14016 element-by-element. We can get to this point when
14017 substituting the type of a non-type template
14018 parameter pack, when that type actually contains
14019 template parameter packs from an outer template, e.g.,
14021 template<typename... Types> struct A {
14022 template<Types... Values> struct B { };
14023 }; */
14027 {
14033 return cp_build_qualified_type_real
14035 }
14037 {
14038 /* We are processing a type constructed from a
14039 template template parameter. */
14050 /* Consider this code:
14052 template <template <class> class Template>
14053 struct Internal {
14054 template <class Arg> using Bind = Template<Arg>;
14055 };
14057 template <template <class> class Template, class Arg>
14058 using Instantiate = Template<Arg>; //#0
14060 template <template <class> class Template,
14061 class Argument>
14062 using Bind =
14063 Instantiate<Internal<Template>::template Bind,
14064 Argument>; //#1
14066 When #1 is parsed, the
14067 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14068 parameter `Template' in #0 matches the
14069 UNBOUND_CLASS_TEMPLATE representing the argument
14070 `Internal<Template>::template Bind'; We then want
14071 to assemble the type `Bind<Argument>' that can't
14072 be fully created right now, because
14073 `Internal<Template>' not being complete, the Bind
14074 template cannot be looked up in that context. So
14075 we need to "store" `Bind<Argument>' for later
14076 when the context of Bind becomes complete. Let's
14077 store that in a TYPENAME_TYPE. */
14081 argvec),
14082 typename_type,
14083 complain);
14085 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14086 are resolving nested-types in the signature of a
14087 member function templates. Otherwise ARG is a
14088 TEMPLATE_DECL and is the real template to be
14089 instantiated. */
14097 complain);
14098 return cp_build_qualified_type_real
14100 }
14103 else
14104 /* TEMPLATE_PARM_INDEX. */
14106 }
14109 /* This can happen during the attempted tsubst'ing in
14110 unify. This means that we don't yet have any information
14111 about the template parameter in question. */
14114 /* If we get here, we must have been looking at a parm for a
14115 more deeply nested template. Make a new version of this
14116 template parameter, but with a lower level. */
14118 {
14123 {
14125 r = cp_build_qualified_type_real
14129 }
14136 /* Break infinite recursion when substituting the constraints
14138 else
14139 {
14150 {
14151 /* Propagate constraints on placeholders. */
14156 {
14159 }
14160 }
14163 /* We have reduced the level of the template
14164 template parameter, but not the levels of its
14165 template parameters, so canonical_type_parameter
14166 will not be able to find the canonical template
14167 template parameter for this level. Thus, we
14168 require structural equality checking to compare
14169 TEMPLATE_TEMPLATE_PARMs. */
14173 else
14177 {
14179 /* We might need to substitute into the types of non-type
14180 template parameters. */
14192 }
14193 }
14197 /* OK, now substitute the type of the non-type parameter. We
14198 couldn't do it earlier because it might be an auto parameter,
14199 and we wouldn't need to if we had an argument. */
14208 }
14211 }
14214 {
14222 {
14226 }
14229 {
14233 }
14236 {
14240 }
14246 }
14249 /* We should never be tsubsting a binfo. */
14253 /* A vector of template arguments. */
14259 {
14263 /* [temp.deduct]
14265 Type deduction may fail for any of the following
14266 reasons:
14268 -- Attempting to create a pointer to reference type.
14269 -- Attempting to create a reference to a reference type or
14270 a reference to void.
14272 Core issue 106 says that creating a reference to a reference
14273 during instantiation is no longer a cause for failure. We
14274 only enforce this check in strict C++98 mode. */
14278 {
14281 /* We keep track of the last time we issued this error
14282 message to avoid spewing a ton of messages during a
14283 single bad template instantiation. */
14286 {
14291 else
14294 }
14297 }
14301 {
14303 {
14306 type);
14307 else
14309 type);
14310 }
14312 }
14314 {
14318 }
14320 /* In C++0x, during template argument substitution, when there is an
14321 attempt to create a reference to a reference type, reference
14322 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14324 "If a template-argument for a template-parameter T names a type
14325 that is a reference to a type A, an attempt to create the type
14326 'lvalue reference to cv T' creates the type 'lvalue reference to
14327 A,' while an attempt to create the type type rvalue reference to
14328 cv T' creates the type T"
14329 */
14330 r = cp_build_reference_type
14333 else
14338 /* Will this ever be needed for TYPE_..._TO values? */
14342 }
14344 {
14347 {
14348 /* [temp.deduct]
14350 Type deduction may fail for any of the following
14351 reasons:
14353 -- Attempting to create "pointer to member of T" when T
14354 is not a class type. */
14358 }
14360 {
14364 }
14366 {
14370 }
14373 {
14374 /* The type of the implicit object parameter gets its
14375 cv-qualifiers from the FUNCTION_TYPE. */
14376 tree memptr;
14377 tree method_type
14382 complain);
14383 }
14384 else
14387 complain);
14388 }
14391 {
14392 tree fntype;
14393 tree specs;
14398 /* Substitute the exception specification. */
14406 }
14408 {
14413 /* As an optimization, we avoid regenerating the array type if
14414 it will obviously be the same as T. */
14418 /* These checks should match the ones in create_array_type_for_decl.
14420 [temp.deduct]
14422 The deduction may fail for any of the following reasons:
14424 -- Attempting to create an array with an element type that
14425 is void, a function type, or a reference type, or [DR337]
14426 an abstract class type. */
14432 {
14436 }
14444 {
14447 }
14450 }
14453 {
14465 {
14469 }
14471 {
14472 /* Normally, make_typename_type does not require that the CTX
14473 have complete type in order to allow things like:
14475 template <class T> struct S { typename S<T>::X Y; };
14477 But, such constructs have already been resolved by this
14478 point, so here CTX really should have complete type, unless
14479 it's a partial instantiation. */
14482 {
14486 }
14487 }
14494 {
14497 }
14500 {
14502 {
14506 else
14508 }
14510 {
14514 else
14516 }
14517 }
14519 return cp_build_qualified_type_real
14521 }
14524 {
14536 }
14539 {
14540 tree type;
14556 complain);
14557 }
14560 {
14561 tree type;
14572 {
14574 {
14578 }
14581 }
14592 else
14593 {
14597 /* In a template ~id could be either a complement expression
14598 or an unqualified-id naming a destructor; if instantiating
14599 it produces an expression, it's not an id-expression or
14600 member access. */
14603 }
14608 }
14611 {
14615 }
14619 {
14620 tree r;
14624 else
14632 }
14647 /* We should use one of the expression tsubsts for these codes. */
14653 }
14654 }
14656 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14657 expression on the left-hand side of the "." or "->" operator. We
14658 only do the lookup if we had a dependent BASELINK. Otherwise we
14659 adjust it onto the instantiated heirarchy. */
14661 static tree
14664 {
14676 {
14683 }
14690 {
14696 /* Treat as-if non-dependent below. */
14701 {
14707 }
14711 }
14712 else
14713 /* We're going to overwrite pieces below, make a duplicate. */
14716 /* If lookup found a single function, mark it as used at this point.
14717 (If lookup found multiple functions the one selected later by
14718 overload resolution will be marked as used at that point.) */
14720 {
14726 /* We might have instantiated an auto function. */
14728 }
14731 {
14732 /* Add back the template arguments, if present. */
14737 /* Update the conversion operator type. */
14739 }
14745 {
14747 qualifying_scope,
14748 object_type);
14750 /* We need to call adjust_result_of_qualified_name_lookup in case the
14751 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14752 so that we still get virtual function binding. */
14754 }
14757 }
14759 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14760 true if the qualified-id will be a postfix-expression in-and-of
14761 itself; false if more of the postfix-expression follows the
14762 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14763 of "&". */
14765 static tree
14769 {
14770 tree expr;
14771 tree scope;
14772 tree name;
14774 tree template_args;
14779 /* Figure out what name to look up. */
14782 {
14792 }
14793 else
14794 {
14797 }
14799 /* Substitute into the qualifying scope. When there are no ARGS, we
14800 are just trying to simplify a non-dependent expression. In that
14801 case the qualifying scope may be dependent, and, in any case,
14802 substituting will not help. */
14805 {
14808 }
14809 else
14813 {
14820 }
14823 {
14825 {
14826 /* A BIT_NOT_EXPR is used to represent a destructor. */
14828 {
14832 }
14833 else
14836 }
14837 else
14841 {
14843 {
14847 }
14849 }
14850 }
14853 {
14855 scope);
14856 /* Remember that there was a reference to this entity. */
14859 }
14862 {
14868 }
14871 {
14874 complain);
14875 else
14877 }
14883 {
14884 expr = (adjust_result_of_qualified_name_lookup
14886 expr = (finish_qualified_id_expr
14890 }
14892 /* Expressions do not generally have reference type. */
14894 /* However, if we're about to form a pointer-to-member, we just
14895 want the referenced member referenced. */
14903 }
14905 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14906 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14907 for tsubst. */
14909 static tree
14912 {
14919 {
14920 /* If we had an initializer but it
14921 instantiated to nothing,
14922 value-initialize the object. This will
14923 only occur when the initializer was a
14924 pack expansion where the parameter packs
14925 used in that expansion were of length
14926 zero. */
14928 complain);
14933 }
14936 }
14938 /* Like tsubst, but deals with expressions. This function just replaces
14939 template parms; to finish processing the resultant expression, use
14940 tsubst_copy_and_build or tsubst_expr. */
14942 static tree
14944 {
14946 tree r;
14954 {
14959 {
14960 /* We get here for a use of 'this' in an NSDMI. */
14964 /* This can happen for a parameter name used later in a function
14965 declaration (such as in a late-specified return type). Just
14966 make a dummy decl, since it's only used for its type. */
14969 /* Give it the template pattern as its context; its true context
14970 hasn't been instantiated yet and this is good enough for
14971 mangling. */
14973 }
14982 {
14983 tree enum_type;
14984 tree v;
14988 /* There is no need to substitute into namespace-scope
14989 enumerators. */
14992 /* If ARGS is NULL, then T is known to be non-dependent. */
14996 /* Unfortunately, we cannot just call lookup_name here.
14997 Consider:
14999 template <int I> int f() {
15000 enum E { a = I };
15001 struct S { void g() { E e = a; } };
15002 };
15004 When we instantiate f<7>::S::g(), say, lookup_name is not
15005 clever enough to find f<7>::a. */
15006 enum_type
15016 /* We didn't find the name. That should never happen; if
15017 name-lookup found it during preliminary parsing, we
15018 should find it again here during instantiation. */
15020 }
15025 {
15026 tree ctx;
15031 {
15034 {
15038 }
15040 }
15041 }
15051 {
15054 {
15055 /* First try name lookup to find the instantiation. */
15058 {
15059 /* Make sure that the one we found is the one we want. */
15063 }
15067 else
15068 {
15069 /* This can happen for a variable used in a
15070 late-specified return type of a local lambda, or for a
15071 local static or constant. Building a new VAR_DECL
15072 should be OK in all those cases. */
15075 /* Avoid infinite recursion (79640). */
15078 {
15079 /* We can't call cp_finish_decl, so handle the
15080 initializer by hand. */
15095 }
15102 }
15103 /* Remember this for subsequent uses. */
15106 }
15109 }
15110 else
15120 /* An OVERLOAD will always be a non-dependent overload set; an
15121 overload set from function scope will just be represented with an
15122 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15124 /* We must have marked any lookups as persistent. */
15140 {
15141 /* Template template argument like the following example need
15142 special treatment:
15144 template <template <class> class TT> struct C {};
15145 template <class T> struct D {
15146 template <class U> struct E {};
15147 C<E> c; // #1
15148 };
15149 D<int> d; // #2
15151 We are processing the template argument `E' in #1 for
15152 the template instantiation #2. Originally, `E' is a
15153 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15154 have to substitute this with one having context `D<int>'. */
15158 {
15159 /* When rewriting a constructor into a deduction guide, a
15160 non-dependent name can become dependent, so memtmpl<args>
15161 becomes context::template memtmpl<args>. */
15165 }
15167 }
15168 else
15169 /* Ordinary template template argument. */
15174 {
15175 /* Handle location wrappers by substituting the wrapped node
15176 first, *then* reusing the resulting type. Doing the type
15177 first ensures that we handle template parameters and
15178 parameter pack expansions. */
15182 }
15192 {
15196 }
15201 {
15210 /* We only want to compute the number of arguments. */
15213 else
15220 {
15222 /* Set TREE_USED for the benefit of -Wunused. */
15226 }
15234 {
15239 else
15245 else
15248 }
15249 else
15251 }
15253 {
15261 }
15262 /* Fall through */
15278 {
15282 }
15285 {
15286 tree object;
15287 tree name;
15292 {
15296 }
15299 {
15309 }
15314 in_decl);
15315 else
15318 }
15356 {
15360 }
15363 {
15368 }
15371 {
15375 }
15378 {
15386 }
15392 {
15399 }
15402 {
15409 }
15412 {
15419 }
15422 {
15423 /* Substituted template arguments */
15432 }
15435 {
15455 }
15480 /* Fall through. */
15483 {
15486 }
15487 else
15491 /* This is handled by tsubst_copy_and_build. */
15495 {
15499 }
15502 /* We shouldn't have built any of these during initial template
15503 generation. Instead, they should be built during instantiation
15504 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15508 {
15518 }
15536 {
15537 /* Instantiate any typedefs in the type. */
15542 }
15545 /* These can sometimes show up in a partial instantiation, but never
15546 involve template parms. */
15562 /* ??? There's no point in copying it for now, but maybe some
15563 day it will contain more information, such as a pointer back
15564 to the containing function, inlined copy or so. */
15568 /* We shouldn't get here, but keep going if !flag_checking. */
15572 }
15573 }
15575 /* Helper function for tsubst_omp_clauses, used for instantiation of
15576 OMP_CLAUSE_DECL of clauses. */
15578 static tree
15580 tree in_decl)
15581 {
15585 /* Handle an OpenMP array section represented as a TREE_LIST (or
15586 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15587 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15588 TREE_LIST. We can handle it exactly the same as an array section
15589 (purpose, value, and a chain), even though the nomenclature
15590 (low_bound, length, etc) is different. */
15592 {
15593 tree low_bound
15599 in_decl);
15608 }
15611 /* Undo convert_from_reference tsubst_expr could have called. */
15617 }
15619 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15621 static tree
15624 {
15629 {
15635 {
15638 {
15644 }
15645 /* FALLTHRU */
15660 in_decl);
15692 {
15695 {
15702 }
15703 else
15705 }
15708 in_decl);
15714 in_decl);
15722 in_decl);
15724 {
15727 }
15732 else
15735 in_decl,
15759 }
15762 {
15772 /* tsubst_expr on SCOPE_REF results in returning
15773 finish_non_static_data_member result. Undo that here. */
15777 {
15782 {
15786 CASE_CONVERT:
15795 /* FALLTHRU */
15799 }
15800 }
15806 {
15809 {
15812 }
15813 }
15817 }
15818 }
15822 {
15827 {
15830 }
15831 }
15833 }
15835 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15837 static tree
15839 tree in_decl)
15840 {
15841 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15861 {
15864 else
15865 {
15869 }
15870 }
15875 #undef RECUR
15876 }
15878 /* Used to temporarily communicate the list of #pragma omp parallel
15879 clauses to #pragma omp for instantiation if they are combined
15880 together. */
15884 /* Substitute one OMP_FOR iterator. */
15886 static void
15891 {
15892 #define RECUR(NODE) \
15893 tsubst_expr ((NODE), args, complain, in_decl, \
15894 integral_constant_expression_p)
15901 {
15904 }
15910 {
15911 /* We need to jump through some hoops to handle declarations in the
15912 init-statement, since we might need to handle auto deduction,
15913 but we need to keep control of initialization. */
15917 }
15918 else
15919 {
15921 {
15924 {
15928 {
15932 CASE_CONVERT:
15940 {
15943 }
15944 /* FALLTHRU */
15948 }
15949 }
15950 }
15951 else
15953 }
15964 {
15966 {
15967 /* Declare the variable, but don't let that initialize it. */
15972 }
15977 {
15982 }
15983 else
15990 }
15993 {
15994 /* Declare and initialize the variable. */
15997 }
15999 {
16003 {
16005 {
16011 {
16014 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16019 }
16022 {
16024 decl);
16026 }
16029 {
16031 decl);
16033 }
16034 else
16036 }
16039 }
16041 {
16046 {
16049 }
16050 }
16051 }
16054 {
16058 }
16059 else
16063 {
16074 {
16082 }
16083 else
16089 {
16095 }
16099 {
16107 }
16108 else
16114 }
16120 #undef RECUR
16121 }
16123 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16124 of OMP_TARGET's body. */
16126 static tree
16128 {
16131 {
16140 }
16142 }
16144 /* Helper function for tsubst_expr. For decomposition declaration
16145 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16146 also the corresponding decls representing the identifiers
16147 of the decomposition declaration. Return DECL if successful
16148 or error_mark_node otherwise, set *FIRST to the first decl
16149 in the list chained through DECL_CHAIN and *CNT to the number
16150 of such decls. */
16152 static tree
16156 {
16161 decl2
16166 {
16168 {
16171 }
16188 {
16191 }
16192 else
16194 }
16197 }
16199 /* Like tsubst_copy for expressions, etc. but also does semantic
16200 processing. */
16202 tree
16205 {
16206 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16207 #define RECUR(NODE) \
16208 tsubst_expr ((NODE), args, complain, in_decl, \
16209 integral_constant_expression_p)
16212 tree r;
16213 location_t loc;
16225 {
16227 {
16228 tree_stmt_iterator i;
16232 }
16247 else
16257 {
16259 tree init;
16265 {
16275 else
16277 }
16280 {
16281 /* We're in tsubst_lambda_expr, we've already inserted a new
16282 capture proxy, so look it up and register it. */
16283 tree inst;
16285 {
16286 inst = (retrieve_local_specialization
16289 }
16290 else
16291 {
16295 }
16298 }
16301 /* Don't copy the old closure; we'll create a new one in
16302 tsubst_lambda_expr. */
16304 else
16305 {
16309 {
16310 /* By marking the declaration as instantiated, we avoid
16311 trying to instantiate it. Since instantiate_decl can't
16312 handle local variables, and since we've already done
16313 all that needs to be done, that's the right thing to
16314 do. */
16319 /* Anonymous aggregates are a special case. */
16322 {
16325 {
16329 }
16331 }
16337 {
16342 }
16343 else
16344 {
16349 {
16350 /* For __PRETTY_FUNCTION__ we have to adjust the
16351 initializer. */
16355 }
16356 else
16360 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16365 {
16367 tree first;
16368 tree ndecl
16376 }
16377 else
16379 }
16380 }
16381 }
16384 }
16394 {
16398 }
16403 {
16404 /* Construct another range_for, if this is not a final
16405 substitution (for inside inside a generic lambda of a
16406 template). Otherwise convert to a regular for. */
16408 stmt = (processing_template_decl
16424 {
16428 }
16429 else
16430 {
16436 }
16442 }
16449 {
16453 }
16459 {
16463 }
16476 else
16477 {
16484 }
16490 {
16499 }
16507 else
16515 else
16536 {
16543 }
16547 {
16549 tree label;
16556 }
16562 /* Computed goto's must be tsubst'd into. On the other hand,
16563 non-computed gotos must not be; the identifier in question
16564 will have no binding. */
16566 else
16572 {
16588 }
16593 {
16598 }
16599 else
16600 {
16605 else
16612 else
16618 else
16620 }
16624 {
16628 {
16630 /* Prevent instantiate_decl from trying to instantiate
16631 this variable. We've already done all that needs to be
16632 done. */
16635 }
16640 }
16646 {
16647 /* Local classes are not independent templates; they are
16648 instantiated along with their containing function. And this
16649 way we don't have to deal with pushing out of one local class
16650 to instantiate a member of another local class. */
16651 /* Closures are handled by the LAMBDA_EXPR. */
16661 }
16665 {
16666 tree condition;
16669 condition =
16671 args,
16680 }
16686 in_decl);
16721 {
16734 in_decl);
16736 {
16743 }
16755 integral_constant_expression_p);
16766 else
16767 {
16775 }
16779 }
16784 /* FALLTHRU */
16791 in_decl);
16808 in_decl);
16819 {
16822 {
16823 /* For combined target teams, ensure the num_teams and
16824 thread_limit clause expressions are evaluated on the host,
16825 before entering the target construct. */
16826 tree c;
16832 {
16841 OMP_CLAUSE_FIRSTPRIVATE);
16845 }
16846 }
16847 }
16907 {
16912 {
16915 }
16921 }
16922 else
16923 {
16930 {
16933 }
16936 {
16941 {
16944 }
16950 }
16951 else
16952 {
16956 }
16959 }
16963 {
16969 {
16973 {
16978 }
16982 }
16983 else
16984 {
16989 }
16990 }
16994 {
16998 }
17011 /* If the first operand was a statement, we're done with it. */
17015 complain));
17029 integral_constant_expression_p));
17030 }
17033 out:
17036 #undef RECUR
17037 #undef RETURN
17038 }
17040 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17041 function. For description of the body see comment above
17042 cp_parser_omp_declare_reduction_exprs. */
17044 static void
17046 {
17052 tree_stmt_iterator tsi;
17063 {
17082 }
17084 {
17104 }
17105 }
17107 /* T is a postfix-expression that is not being used in a function
17108 call. Return the substituted version of T. */
17110 static tree
17112 tsubst_flags_t complain,
17113 tree in_decl)
17114 {
17118 else
17124 }
17126 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17127 instantiation context. Instantiating a pack expansion containing a lambda
17128 might result in multiple lambdas all based on the same lambda in the
17129 template. */
17131 tree
17133 {
17147 else
17155 {
17167 else
17172 {
17181 }
17182 else
17183 {
17189 }
17190 }
17194 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17212 else
17213 {
17214 /* Fix the type of 'this'. */
17220 {
17224 }
17225 else
17226 {
17230 }
17232 /* Let finish_function set this. */
17238 else
17239 /* Still increment function_depth so that we don't GC in the
17240 middle of an expression. */
17256 else
17259 /* The capture list was built up in reverse order; fix that now. */
17266 }
17273 }
17275 /* Like tsubst but deals with expressions and performs semantic
17276 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17278 tree
17280 tree args,
17281 tsubst_flags_t complain,
17282 tree in_decl,
17285 {
17286 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17287 #define RECUR(NODE) \
17288 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17290 integral_constant_expression_p)
17293 location_t loc;
17302 /* N3276 decltype magic only applies to calls at the top level or on the
17303 right side of a comma. */
17308 {
17311 /* Fall through. */
17313 {
17314 tree decl;
17315 cp_id_kind idk;
17320 {
17323 }
17325 /* Look up the name. */
17328 /* By convention, expressions use ERROR_MARK_NODE to indicate
17329 failure, not NULL_TREE. */
17335 integral_constant_expression_p,
17343 input_location);
17347 {
17351 }
17353 }
17356 {
17357 tree object;
17367 {
17372 }
17378 {
17381 }
17382 else
17389 else
17391 }
17394 {
17398 {
17399 /* A type conversion to reference type will be enclosed in
17400 such an indirect ref, but the substitution of the cast
17401 will have also added such an indirect ref. */
17403 }
17404 else
17412 }
17415 {
17419 }
17422 {
17426 {
17431 }
17433 /* We'll pass this to convert_nontype_argument again, we don't need
17434 to actually perform any conversion here. */
17440 flags));
17441 }
17444 {
17450 }
17457 {
17458 tree type;
17464 {
17469 }
17476 {
17494 }
17497 }
17530 else
17532 in_decl);
17567 {
17574 tree r = build_x_binary_op
17576 op0,
17578 ? ERROR_MARK
17580 op1,
17582 ? ERROR_MARK
17590 }
17593 {
17597 }
17613 /* Fall through */
17616 {
17617 tree r;
17623 {
17624 /* When there are no ARGS, we are trying to evaluate a
17625 non-dependent expression from the parser. Trying to do
17626 the substitutions may not work. */
17629 }
17630 else
17631 {
17636 else
17639 /*integral_constant_expression_p=*/
17643 }
17647 else
17651 {
17653 {
17655 {
17659 }
17660 else
17664 }
17666 }
17668 }
17671 {
17681 }
17697 {
17701 tree r = build_x_modify_expr
17704 /* TREE_NO_WARNING must be set if either the expression was
17705 parenthesized or it uses an operator such as >>= rather
17706 than plain assignment. In the former case, it was already
17707 set and must be copied. In the latter case,
17708 build_x_modify_expr sets it and it must not be reset
17709 here. */
17714 }
17719 /* Remember that there was a reference to this entity. */
17726 {
17731 tree ret;
17735 else
17736 {
17740 }
17742 /* If there was an initializer in the original tree, but it
17743 instantiated to an empty list, then we should pass a
17744 non-NULL empty vector to tell build_new that it was an
17745 empty initializer() rather than no initializer. This can
17746 only happen when the initializer is a pack expansion whose
17747 parameter packs are of length zero. */
17750 else
17751 {
17755 else
17756 {
17759 }
17760 }
17766 complain);
17774 }
17777 {
17783 complain));
17784 }
17787 {
17791 integral_constant_expression_p);
17793 op0,
17796 }
17799 {
17800 tree function;
17805 tree ret;
17808 /* Internal function with no arguments. */
17812 /* When we parsed the expression, we determined whether or
17813 not Koenig lookup should be performed. */
17816 {
17819 }
17821 {
17826 }
17828 {
17829 /* Do nothing; calling tsubst_copy_and_build on an identifier
17830 would incorrectly perform unqualified lookup again.
17832 Note that we can also have an IDENTIFIER_NODE if the earlier
17833 unqualified lookup found a member function; in that case
17834 koenig_p will be false and we do want to do the lookup
17835 again to find the instantiated member function.
17837 FIXME but doing that causes c++/15272, so we need to stop
17838 using IDENTIFIER_NODE in that situation. */
17840 }
17841 else
17842 {
17844 {
17850 }
17851 else
17856 /* Avoid error about taking the address of a constructor. */
17860 in_decl,
17862 integral_constant_expression_p);
17866 }
17871 {
17876 else
17877 {
17878 /* Expand the pack expansion and push each entry onto
17879 CALL_ARGS. */
17882 {
17887 {
17892 }
17893 }
17894 else
17895 {
17896 /* A partial substitution. Add one entry. */
17898 }
17899 }
17900 }
17902 /* We do not perform argument-dependent lookup if normal
17903 lookup finds a non-function, in accordance with the
17904 expected resolution of DR 218. */
17907 /* If lookup found a member function, the Koenig lookup is
17908 not appropriate, even if an unqualified-name was used
17909 to denote the function. */
17912 /* Only do this when substitution turns a dependent call
17913 into a non-dependent call. */
17921 {
17923 {
17924 /* For backwards compatibility and good diagnostics, try
17925 the unqualified lookup again if we aren't in SFINAE
17926 context. */
17927 tree unq = (tsubst_copy_and_build
17929 integral_constant_expression_p));
17931 {
17934 }
17937 {
17938 /* In a lambda fn, we have to be careful to not
17939 introduce new this captures. Legacy code can't
17940 be using lambdas anyway, so it's ok to be
17941 stricter. */
17946 "and no declarations were found by "
17947 "argument-dependent lookup at the point "
17954 else
17958 {
17969 {
17971 input_location);
17973 "declarations in dependent base %qT are "
17979 else
17983 }
17984 else
17986 "%qD declared here, later in the "
17989 {
17992 }
17993 }
17996 }
17997 }
17999 {
18004 }
18005 }
18007 /* Remember that there was a reference to this entity. */
18011 {
18014 }
18016 /* Put back tf_decltype for the actual call. */
18021 {
18025 {
18027 "wrong number of arguments to "
18030 }
18031 else
18033 input_location),
18038 /* Unsupported internal function with arguments. */
18040 }
18043 complain);
18045 {
18060 complain);
18061 else
18062 ret = (build_new_method_call
18067 complain));
18068 }
18069 else
18072 koenig_p,
18073 complain);
18078 {
18084 {
18090 {
18093 else
18095 /* The thunk location is not interesting. */
18097 }
18098 }
18099 }
18102 }
18105 {
18111 {
18113 {
18118 }
18119 else
18120 {
18125 }
18127 }
18128 else
18129 {
18132 }
18137 }
18140 {
18145 input_location));
18146 }
18149 {
18157 {
18158 /* We have pack expansions, so expand those and
18159 create a new list out of it. */
18162 tree chain;
18165 /* Expand the argument expressions. */
18173 /* Build the rest of the list. */
18178 /* Determine the number of arguments. */
18180 {
18183 }
18186 else
18187 {
18188 /* Since we only performed a partial substitution into
18189 the argument pack, we only RETURN (a single list
18190 node. */
18197 }
18199 /* Convert the argument vectors into a TREE_LIST */
18202 {
18203 /* Grab the Ith values. */
18204 i--;
18207 value
18211 /* Build the list (backwards). */
18213 }
18216 }
18232 }
18235 {
18236 tree object;
18237 tree object_type;
18238 tree member;
18239 tree r;
18243 /* Remember that there was a reference to this entity. */
18254 else
18260 {
18265 }
18269 {
18271 {
18276 {
18279 }
18281 {
18286 }
18287 }
18288 }
18291 {
18292 /* Lookup the template functions now that we know what the
18293 scope is. */
18301 {
18304 args);
18305 member = (adjust_result_of_qualified_name_lookup
18307 object_type));
18308 }
18309 else
18310 {
18312 input_location);
18314 }
18315 }
18319 {
18321 {
18325 else
18328 }
18330 }
18334 complain);
18338 }
18345 {
18353 tree r;
18358 /* We do not want to process the index of aggregate
18359 initializers as they are identifier nodes which will be
18360 looked up by digest_init. */
18366 {
18368 /* An identifier index is looked up in the type
18369 being initialized, not the current scope. */
18374 {
18375 /* Substitute into the pack expansion. */
18377 in_decl);
18381 ;
18383 /* Just move the argument into place. */
18385 else
18386 {
18387 /* Update the length of the final CONSTRUCTOR
18388 arguments vector, and note that we will need to
18389 copy.*/
18392 }
18393 }
18394 else
18396 }
18399 {
18404 {
18406 {
18411 }
18412 else
18414 }
18415 }
18421 {
18426 }
18430 }
18433 {
18436 {
18439 }
18440 else
18441 {
18444 }
18445 }
18450 /* Fall through */
18453 {
18455 /* ??? We're doing a subset of finish_id_expression here. */
18457 && !processing_template_decl
18458 && !cp_unevaluated_operand
18461 {
18463 /* Replace an evaluated use of the thread_local variable with
18464 a call to its wrapper. */
18466 }
18471 /* If the original type was a reference, we'll be wrapped in
18472 the appropriate INDIRECT_REF. */
18475 }
18478 {
18482 }
18485 {
18486 tree object_ptr
18493 }
18500 {
18511 }
18514 {
18520 integral_constant_expression_p);
18524 /* If the resulting list of expression statement is empty,
18525 fold it further into void_node. */
18530 }
18533 {
18537 }
18540 /* We can get here for a constant initializer of non-dependent type.
18541 FIXME stop folding in cp_parser_initializer_clause. */
18542 {
18544 complain);
18546 }
18550 integral_constant_expression_p));
18556 {
18561 complain));
18562 }
18569 /* We should only see these for location wrapper nodes, or within
18570 instantiate_non_dependent_expr (when args is NULL_TREE). */
18575 /* fallthrough. */
18578 /* Handle Objective-C++ constructs, if appropriate. */
18579 {
18580 tree subst
18585 }
18587 }
18589 #undef RECUR
18590 #undef RETURN
18591 out:
18594 }
18596 /* Verify that the instantiated ARGS are valid. For type arguments,
18597 make sure that the type's linkage is ok. For non-type arguments,
18598 make sure they are constants if they are integral or enumerations.
18599 Emit an error under control of COMPLAIN, and return TRUE on error. */
18601 static bool
18603 {
18607 {
18617 }
18619 {
18620 /* [basic.link]: A name with no linkage (notably, the name
18621 of a class or enumeration declared in a local scope)
18622 shall not be used to declare an entity with linkage.
18623 This implies that names with no linkage cannot be used as
18624 template arguments
18626 DR 757 relaxes this restriction for C++0x. */
18631 {
18632 /* DR 488 makes use of a type with no linkage cause
18633 type deduction to fail. */
18635 {
18638 else
18641 }
18643 }
18644 /* In order to avoid all sorts of complications, we do not
18645 allow variably-modified types as template arguments. */
18647 {
18651 }
18652 }
18653 /* Class template and alias template arguments should be OK. */
18655 ;
18656 /* A non-type argument of integral or enumerated type must be a
18657 constant. */
18662 {
18666 }
18668 }
18670 static bool
18672 {
18677 {
18680 }
18684 }
18686 /* We're out of SFINAE context now, so generate diagnostics for the access
18687 errors we saw earlier when instantiating D from TMPL and ARGS. */
18689 static void
18691 {
18703 }
18705 /* Instantiate the indicated variable, function, or alias template TMPL with
18706 the template arguments in TARG_PTR. */
18708 static tree
18710 {
18712 tree fndecl;
18713 tree gen_tmpl;
18714 tree spec;
18722 /* If this function is a clone, handle it specially. */
18724 {
18725 tree spec;
18726 tree clone;
18728 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18729 DECL_CLONED_FUNCTION. */
18735 /* Look for the clone. */
18739 /* We should always have found the clone by now. */
18742 }
18747 /* Check to see if we already have this specialization. */
18751 /* targ_ptr only has the innermost template args, so add the outer ones
18752 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18753 the case of a non-dependent call within a template definition). */
18754 targ_ptr = (add_outermost_template_args
18756 targ_ptr));
18758 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18759 but it doesn't seem to be on the hot path. */
18768 {
18770 {
18774 }
18776 }
18779 complain))
18782 /* We are building a FUNCTION_DECL, during which the access of its
18783 parameters and return types have to be checked. However this
18784 FUNCTION_DECL which is the desired context for access checking
18785 is not built yet. We solve this chicken-and-egg problem by
18786 deferring all checks until we have the FUNCTION_DECL. */
18789 /* Instantiation of the function happens in the context of the function
18790 template, not the context of the overload resolution we're doing. */
18792 /* If there are dependent arguments, e.g. because we're doing partial
18793 ordering, make sure processing_template_decl stays set. */
18797 {
18801 }
18807 {
18808 /* We need to determine if we're using a partial or explicit
18809 specialization now, because the type of the variable could be
18810 different. */
18816 {
18821 }
18822 }
18824 /* Substitute template parameters to obtain the specialization. */
18832 {
18835 }
18837 /* The DECL_TI_TEMPLATE should always be the immediate parent
18838 template, not the most general template. */
18842 /* Now we know the specialization, compute access previously
18843 deferred. Do no access control for inheriting constructors,
18844 as we already checked access for the inherited constructor. */
18847 {
18852 }
18855 /* If we've just instantiated the main entry point for a function,
18856 instantiate all the alternate entry points as well. We do this
18857 by cloning the instantiation of the main entry point, not by
18858 instantiating the template clones. */
18863 {
18865 {
18866 /* Remember to reinstantiate when we're out of SFINAE so the user
18867 can see the errors. */
18869 }
18871 }
18873 }
18875 /* Wrapper for instantiate_template_1. */
18877 tree
18879 {
18880 tree ret;
18885 }
18887 /* Instantiate the alias template TMPL with ARGS. Also push a template
18888 instantiation level, which instantiate_template doesn't do because
18889 functions and variables have sufficient context established by the
18890 callers. */
18892 static tree
18894 {
18901 {
18904 }
18906 args =
18914 /* We can't free this if a pending_template entry or last_error_tinst_level
18915 is pointing at it. */
18921 }
18923 /* PARM is a template parameter pack for FN. Returns true iff
18924 PARM is used in a deducible way in the argument list of FN. */
18926 static bool
18928 {
18931 {
18933 tree packs;
18939 {
18940 /* The template parameter pack is used in a function parameter
18941 pack. If this is the end of the parameter list, the
18942 template parameter pack is deducible. */
18945 else
18946 /* Otherwise, not. Well, it could be deduced from
18947 a non-pack parameter, but doing so would end up with
18948 a deduction mismatch, so don't bother. */
18950 }
18951 }
18952 /* The template parameter pack isn't used in any function parameter
18953 packs, but it might be used deeper, e.g. tuple<Args...>. */
18955 }
18957 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18958 NARGS elements of the arguments that are being used when calling
18959 it. TARGS is a vector into which the deduced template arguments
18960 are placed.
18962 Returns either a FUNCTION_DECL for the matching specialization of FN or
18963 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18964 true, diagnostics will be printed to explain why it failed.
18966 If FN is a conversion operator, or we are trying to produce a specific
18967 specialization, RETURN_TYPE is the return type desired.
18969 The EXPLICIT_TARGS are explicit template arguments provided via a
18970 template-id.
18972 The parameter STRICT is one of:
18974 DEDUCE_CALL:
18975 We are deducing arguments for a function call, as in
18976 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18977 deducing arguments for a call to the result of a conversion
18978 function template, as in [over.call.object].
18980 DEDUCE_CONV:
18981 We are deducing arguments for a conversion function, as in
18982 [temp.deduct.conv].
18984 DEDUCE_EXACT:
18985 We are deducing arguments when doing an explicit instantiation
18986 as in [temp.explicit], when determining an explicit specialization
18987 as in [temp.expl.spec], or when taking the address of a function
18988 template, as in [temp.deduct.funcaddr]. */
18990 tree
18992 tree explicit_targs,
18993 tree targs,
18996 tree return_type,
18997 unification_kind_t strict,
19001 {
19002 tree parms;
19003 tree fntype;
19016 tree tinst;
19022 full_targs = (add_outermost_template_args
19024 targs));
19029 /* In C++0x, it's possible to have a function template whose type depends
19030 on itself recursively. This is most obvious with decltype, but can also
19031 occur with enumeration scope (c++/48969). So we need to catch infinite
19032 recursion and reject the substitution at deduction time; this function
19033 will return error_mark_node for any repeated substitution.
19035 This also catches excessive recursion such as when f<N> depends on
19036 f<N-1> across all integers, and returns error_mark_node for all the
19037 substitutions back up to the initial one.
19039 This is, of course, not reentrant. */
19049 {
19050 /* [temp.deduct]
19052 The specified template arguments must match the template
19053 parameters in kind (i.e., type, nontype, template), and there
19054 must not be more arguments than there are parameters;
19055 otherwise type deduction fails.
19057 Nontype arguments must match the types of the corresponding
19058 nontype template parameters, or must be convertible to the
19059 types of the corresponding nontype parameters as specified in
19060 _temp.arg.nontype_, otherwise type deduction fails.
19062 All references in the function type of the function template
19063 to the corresponding template parameters are replaced by the
19064 specified template argument values. If a substitution in a
19065 template parameter or in the function type of the function
19066 template results in an invalid type, type deduction fails. */
19077 explicit_targs);
19079 /* Adjust any explicit template arguments before entering the
19080 substitution context. */
19081 explicit_targs
19083 complain,
19089 /* Substitute the explicit args into the function type. This is
19090 necessary so that, for instance, explicitly declared function
19091 arguments can match null pointed constants. If we were given
19092 an incomplete set of explicit args, we must not do semantic
19093 processing during substitution as we could create partial
19094 instantiations. */
19096 {
19101 /* Dig out the actual parm. */
19104 {
19107 }
19109 {
19112 }
19115 /* No explicit argument for this template parameter. */
19119 {
19120 /* Mark the argument pack as "incomplete". We could
19121 still deduce more arguments during unification.
19122 We remove this mark in type_unification_real. */
19124 {
19128 }
19130 /* We have some incomplete argument packs. */
19132 }
19133 }
19137 {
19140 }
19143 /* Ignore any access checks; we'll see them again in
19144 instantiate_template and they might have the wrong
19145 access path at this point. */
19157 /* Place the explicitly specified arguments in TARGS. */
19161 }
19163 /* Never do unification on the 'this' parameter. */
19167 {
19168 /* We're deducing for a call to the result of a template conversion
19169 function. The parms we really want are in return_type. */
19173 }
19175 {
19184 }
19186 /* We allow incomplete unification without an error message here
19187 because the standard doesn't seem to explicitly prohibit it. Our
19188 callers must be ready to deal with unification failures in any
19189 event. */
19192 /* If we aren't explaining yet, push tinst context so we can see where
19193 any errors (e.g. from class instantiations triggered by instantiation
19194 of default template arguments) come from. If we are explaining, this
19195 context is redundant. */
19197 {
19200 }
19202 /* type_unification_real will pass back any access checks from default
19203 template argument substitution. */
19215 /* Now that we have bindings for all of the template arguments,
19216 ensure that the arguments deduced for the template template
19217 parameters have compatible template parameter lists. We cannot
19218 check this property before we have deduced all template
19219 arguments, because the template parameter types of a template
19220 template parameter might depend on prior template parameters
19221 deduced after the template template parameter. The following
19222 ill-formed example illustrates this issue:
19224 template<typename T, template<T> class C> void f(C<5>, T);
19226 template<int N> struct X {};
19228 void g() {
19229 f(X<5>(), 5l); // error: template argument deduction fails
19230 }
19232 The template parameter list of 'C' depends on the template type
19233 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19234 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19235 time that we deduce 'C'. */
19238 {
19241 }
19243 /* All is well so far. Now, check:
19245 [temp.deduct]
19247 When all template arguments have been deduced, all uses of
19248 template parameters in nondeduced contexts are replaced with
19249 the corresponding deduced argument values. If the
19250 substitution results in an invalid type, as described above,
19251 type deduction fails. */
19254 {
19257 }
19259 /* Also collect access checks from the instantiation. */
19272 /* Now perform any access checks encountered during substitution. */
19279 /* If we're looking for an exact match, check that what we got
19280 is indeed an exact match. It might not be if some template
19281 parameters are used in non-deduced contexts. But don't check
19282 for an exact match if we have dependent template arguments;
19283 in that case we're doing partial ordering, and we already know
19284 that we have two candidates that will provide the actual type. */
19286 {
19290 tree sarg
19296 {
19300 }
19301 }
19303 /* After doing deduction with the inherited constructor, actually return an
19304 instantiation of the inheriting constructor. */
19310 fail:
19313 {
19315 /* Reset once we're all the way out. */
19317 }
19319 /* We can't free this if a pending_template entry or last_error_tinst_level
19320 is pointing at it. */
19326 }
19328 /* Adjust types before performing type deduction, as described in
19329 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19330 sections are symmetric. PARM is the type of a function parameter
19331 or the return type of the conversion function. ARG is the type of
19332 the argument passed to the call, or the type of the value
19333 initialized with the result of the conversion function.
19334 ARG_EXPR is the original argument expression, which may be null. */
19336 static int
19340 tree arg_expr)
19341 {
19345 {
19350 /* Swap PARM and ARG throughout the remainder of this
19351 function; the handling is precisely symmetric since PARM
19352 will initialize ARG rather than vice versa. */
19357 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19358 too, but here handle it by stripping the reference from PARM
19359 rather than by adding it to ARG. */
19367 /* Nothing else to do in this case. */
19372 }
19375 {
19376 /* [temp.deduct.call]
19378 If P is not a reference type:
19380 --If A is an array type, the pointer type produced by the
19381 array-to-pointer standard conversion (_conv.array_) is
19382 used in place of A for type deduction; otherwise,
19384 --If A is a function type, the pointer type produced by
19385 the function-to-pointer standard conversion
19386 (_conv.func_) is used in place of A for type deduction;
19387 otherwise,
19389 --If A is a cv-qualified type, the top level
19390 cv-qualifiers of A's type are ignored for type
19391 deduction. */
19396 else
19398 }
19400 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19401 reference to a cv-unqualified template parameter that does not represent a
19402 template parameter of a class template (during class template argument
19403 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19404 an lvalue, the type "lvalue reference to A" is used in place of A for type
19405 deduction. */
19412 /* try_one_overload doesn't provide an arg_expr, but
19413 functions are always lvalues. */
19417 /* [temp.deduct.call]
19419 If P is a cv-qualified type, the top level cv-qualifiers
19420 of P's type are ignored for type deduction. If P is a
19421 reference type, the type referred to by P is used for
19422 type deduction. */
19425 {
19428 }
19430 /* DR 322. For conversion deduction, remove a reference type on parm
19431 too (which has been swapped into ARG). */
19436 }
19438 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19439 template which does contain any deducible template parameters; check if
19440 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19441 unify_one_argument. */
19443 static int
19446 {
19447 tree type;
19451 else
19458 {
19462 }
19464 {
19469 }
19473 else
19475 }
19479 /* Returns true iff the expression EXPR is one from which a template
19480 argument can be deduced. In other words, if it's an undecorated
19481 use of a template non-type parameter. */
19483 static bool
19485 {
19486 /* Strip implicit conversions. */
19490 }
19492 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19493 deducible way; that is, if it has a max value of <PARM> - 1. */
19495 static bool
19497 {
19506 }
19508 /* Returns true iff the template arguments ARGS use a template parameter
19509 in a deducible way. */
19511 static bool
19513 {
19515 {
19520 else
19521 {
19528 else
19530 }
19533 }
19535 }
19537 /* Returns true iff TYPE contains any deducible references to template
19538 parameters, as per 14.8.2.5. */
19540 static bool
19542 {
19546 /* T
19547 cv-list T
19548 TT<T>
19549 TT<i>
19550 TT<> */
19555 /* T*
19556 T&
19557 T&& */
19561 /* T[integer-constant ]
19562 type [i] */
19567 /* T type ::*
19568 type T::*
19569 T T::*
19570 T (type ::*)()
19571 type (T::*)()
19572 type (type ::*)(T)
19573 type (T::*)(T)
19574 T (type ::*)(T)
19575 T (T::*)()
19576 T (T::*)(T) */
19579 || (uses_deducible_template_parms
19582 /* template-name <T> (where template-name refers to a class template)
19583 template-name <i> (where template-name refers to a class template) */
19590 /* type (T)
19591 T()
19592 T(T) */
19595 {
19604 }
19607 }
19609 /* Subroutine of type_unification_real and unify_pack_expansion to
19610 handle unification of a single P/A pair. Parameters are as
19611 for those functions. */
19613 static int
19617 {
19624 /* We can't deduce anything from this, but we might get all the
19625 template args from other function args. */
19628 /* Implicit conversions (Clause 4) will be performed on a function
19629 argument to convert it to the type of the corresponding function
19630 parameter if the parameter type contains no template-parameters that
19631 participate in template argument deduction. */
19634 /* For function parameters with no deducible template parameters,
19635 just return. We'll check non-dependent conversions later. */
19639 {
19641 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19642 | UNIFY_ALLOW_MORE_CV_QUAL
19656 }
19658 /* We only do these transformations if this is the top-level
19659 parameter_type_list in a call or declaration matching; in other
19660 situations (nested function declarators, template argument lists) we
19661 won't be comparing a type to an expression, and we don't do any type
19662 adjustments. */
19664 {
19666 {
19669 {
19670 /* [temp.deduct.type] A template-argument can be
19671 deduced from a pointer to function or pointer
19672 to member function argument if the set of
19673 overloaded functions does not contain function
19674 templates and at most one of a set of
19675 overloaded functions provides a unique
19676 match. */
19680 /* If a unique match was not found, this is a
19681 non-deduced context, so we still succeed. */
19683 }
19689 }
19691 arg_strict |=
19693 }
19694 else
19699 /* For deduction from an init-list we need the actual list. */
19703 }
19705 /* for_each_template_parm callback that always returns 0. */
19707 static int
19709 {
19711 }
19713 /* for_each_template_parm any_fn callback to handle deduction of a template
19714 type argument from the type of an array bound. */
19716 static int
19718 {
19726 {
19732 }
19734 /* Keep walking. */
19736 }
19738 /* Try to deduce any not-yet-deduced template type arguments from the type of
19739 an array bound. This is handled separately from unify because 14.8.2.5 says
19740 "The type of a type parameter is only deduced from an array bound if it is
19741 not otherwise deduced." */
19743 static void
19745 {
19750 }
19752 /* Most parms like fn_type_unification.
19754 If SUBR is 1, we're being called recursively (to unify the
19755 arguments of a function or method parameter of a function
19756 template).
19758 CHECKS is a pointer to a vector of access checks encountered while
19759 substituting default template arguments. */
19761 static int
19763 tree full_targs,
19764 tree xparms,
19768 unification_kind_t strict,
19772 {
19777 tree parms;
19788 /* Reset the number of non-defaulted template arguments contained
19789 in TARGS. */
19792 again:
19800 {
19805 /* For a function parameter pack that occurs at the end of the
19806 parameter-declaration-list, the type A of each remaining
19807 argument of the call is compared with the type P of the
19808 declarator-id of the function parameter pack. */
19814 /* For a function parameter pack that does not occur at the
19815 end of the parameter-declaration-list, the type of the
19816 parameter pack is a non-deduced context. */
19823 explain_p))
19825 }
19830 {
19831 /* Unify the remaining arguments with the pack expansion type. */
19832 tree argvec;
19835 /* Allocate a TREE_VEC and copy in all of the arguments */
19840 /* Copy the parameter into parmvec. */
19846 /* Advance to the end of the list of parameters. */
19848 }
19850 /* Fail if we've reached the end of the parm list, and more args
19851 are present, and the parm list isn't variadic. */
19854 /* Fail if parms are left and they don't have default values and
19855 they aren't all deduced as empty packs (c++/57397). This is
19856 consistent with sufficient_parms_p. */
19859 {
19863 do
19864 {
19867 count++;
19869 }
19873 type_pack_p);
19874 }
19877 {
19878 tsubst_flags_t complain = (explain_p
19879 ? tf_warning_or_error
19884 {
19888 /* Clear the "incomplete" flags on all argument packs now so that
19889 substituting them into later default arguments works. */
19891 {
19894 }
19902 {
19907 }
19909 /* If this is an undeduced nontype parameter that depends on
19910 a type parameter, try another pass; its type may have been
19911 deduced from a later argument than the one from which
19912 this parameter can be deduced. */
19916 {
19919 }
19921 /* Core issue #226 (C++0x) [temp.deduct]:
19923 If a template argument has not been deduced, its
19924 default template argument, if any, is used.
19926 When we are in C++98 mode, TREE_PURPOSE will either
19927 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19928 to explicitly check cxx_dialect here. */
19930 /* OK, there is a default argument. Wait until after the
19931 conversion check to do substitution. */
19934 /* If the type parameter is a parameter pack, then it will
19935 be deduced to an empty parameter pack. */
19937 {
19938 tree arg;
19941 {
19944 }
19945 else
19952 }
19955 }
19957 /* DR 1391: All parameters have args, now check non-dependent parms for
19958 convertibility. */
19962 {
19968 /* For a function parameter pack that occurs at the end of the
19969 parameter-declaration-list, the type A of each remaining
19970 argument of the call is compared with the type P of the
19971 declarator-id of the function parameter pack. */
19977 /* For a function parameter pack that does not occur at the
19978 end of the parameter-declaration-list, the type of the
19979 parameter pack is a non-deduced context. */
19988 explain_p))
19990 }
19992 /* Now substitute into the default template arguments. */
19994 {
20012 {
20013 /* The type of this non-type parameter depends on undeduced
20014 parameters. Don't try to use its default argument yet,
20015 but do check whether the arguments we already have cause
20016 substitution failure, so that that happens before we try
20017 later default arguments (78489). */
20019 NULL_TREE);
20022 else
20024 }
20025 else
20026 {
20034 else
20036 }
20047 {
20049 /* The position of the first default template argument,
20050 is also the number of non-defaulted arguments in TARGS.
20051 Record that. */
20054 }
20055 }
20059 }
20065 }
20067 /* Subroutine of type_unification_real. Args are like the variables
20068 at the call site. ARG is an overloaded function (or template-id);
20069 we try deducing template args from each of the overloads, and if
20070 only one succeeds, we go with that. Modifies TARGS and returns
20071 true on success. */
20073 static bool
20075 tree targs,
20076 tree parm,
20077 tree arg,
20078 unification_kind_t strict,
20081 {
20088 {
20091 }
20092 else
20096 /* Handle `&x' where `x' is some static or non-static member
20097 function name. */
20103 /* Strip baselink information. */
20108 {
20109 /* If we got some explicit template args, we need to plug them into
20110 the affected templates before we try to unify, in case the
20111 explicit args will completely resolve the templates in question. */
20118 {
20131 {
20136 {
20139 }
20140 }
20143 }
20144 /* If no templates (or more than one) are fully resolved by the
20145 explicit arguments, this template-id is a non-deduced context; it
20146 could still be OK if we deduce all template arguments for the
20147 enclosing call through other arguments. */
20150 }
20153 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20154 -- but the deduction does not succeed because the expression is
20155 not just the function on its own. */
20157 else
20159 {
20164 {
20167 }
20168 }
20170 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20171 to function or pointer to member function argument if the set of
20172 overloaded functions does not contain function templates and at most
20173 one of a set of overloaded functions provides a unique match.
20175 So if we found multiple possibilities, we return success but don't
20176 deduce anything. */
20179 {
20183 {
20188 /* Don't forget explicit template arguments in a pack. */
20192 }
20193 }
20198 }
20200 /* Core DR 115: In contexts where deduction is done and fails, or in
20201 contexts where deduction is not done, if a template argument list is
20202 specified and it, along with any default template arguments, identifies
20203 a single function template specialization, then the template-id is an
20204 lvalue for the function template specialization. */
20206 tree
20208 {
20221 {
20224 }
20226 {
20229 }
20231 {
20234 }
20237 {
20241 /* If we got some explicit template args, we need to plug them into
20242 the affected templates before we try to unify, in case the
20243 explicit args will completely resolve the templates in question. */
20251 {
20264 {
20267 {
20270 }
20272 {
20275 }
20276 }
20277 }
20279 {
20287 {
20288 tree base
20291 }
20295 }
20297 /* There were no good options and at least one bad one, so let the
20298 user know what the problem is. */
20300 }
20302 }
20304 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20305 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20306 different overloads deduce different arguments for a given parm.
20307 ADDR_P is true if the expression for which deduction is being
20308 performed was of the form "& fn" rather than simply "fn".
20310 Returns 1 on success. */
20312 static int
20314 tree orig_targs,
20315 tree targs,
20316 tree parm,
20317 tree arg,
20318 unification_kind_t strict,
20322 {
20324 tree tempargs;
20330 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20331 to function or pointer to member function argument if the set of
20332 overloaded functions does not contain function templates and at most
20333 one of a set of overloaded functions provides a unique match.
20335 So if this is a template, just return success. */
20347 /* We don't copy orig_targs for this because if we have already deduced
20348 some template args from previous args, unify would complain when we
20349 try to deduce a template parameter for the same argument, even though
20350 there isn't really a conflict. */
20357 /* First make sure we didn't deduce anything that conflicts with
20358 explicitly specified args. */
20360 {
20367 /* Since we're unifying against ourselves, we will fill in
20368 template args used in the function parm list with our own
20369 template parms. Discard them. */
20372 {
20373 /* Check that the argument at each index of the deduced argument pack
20374 is equivalent to the corresponding explicitly specified argument.
20375 We may have deduced more arguments than were explicitly specified,
20376 and that's OK. */
20378 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20379 that's wrong if we deduce the same argument pack from multiple
20380 function arguments: it's only incomplete the first time. */
20393 }
20396 }
20399 {
20404 }
20407 }
20409 /* PARM is a template class (perhaps with unbound template
20410 parameters). ARG is a fully instantiated type. If ARG can be
20411 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20412 TARGS are as for unify. */
20414 static tree
20417 {
20418 tree copy_of_targs;
20428 /* We need to make a new template argument vector for the call to
20429 unify. If we used TARGS, we'd clutter it up with the result of
20430 the attempted unification, even if this class didn't work out.
20431 We also don't want to commit ourselves to all the unifications
20432 we've already done, since unification is supposed to be done on
20433 an argument-by-argument basis. In other words, consider the
20434 following pathological case:
20436 template <int I, int J, int K>
20437 struct S {};
20439 template <int I, int J>
20440 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20442 template <int I, int J, int K>
20443 void f(S<I, J, K>, S<I, I, I>);
20445 void g() {
20446 S<0, 0, 0> s0;
20447 S<0, 1, 2> s2;
20449 f(s0, s2);
20450 }
20452 Now, by the time we consider the unification involving `s2', we
20453 already know that we must have `f<0, 0, 0>'. But, even though
20454 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20455 because there are two ways to unify base classes of S<0, 1, 2>
20456 with S<I, I, I>. If we kept the already deduced knowledge, we
20457 would reject the possibility I=1. */
20461 {
20465 }
20467 /* If unification failed, we're done. */
20473 }
20475 /* Given a template type PARM and a class type ARG, find the unique
20476 base type in ARG that is an instance of PARM. We do not examine
20477 ARG itself; only its base-classes. If there is not exactly one
20478 appropriate base class, return NULL_TREE. PARM may be the type of
20479 a partial specialization, as well as a plain template type. Used
20480 by unify. */
20482 static enum template_base_result
20485 {
20487 tree binfo;
20493 {
20494 /* The type could not be completed. */
20497 }
20499 /* Walk in inheritance graph order. The search order is not
20500 important, and this avoids multiple walks of virtual bases. */
20502 {
20507 {
20508 /* If there is more than one satisfactory baseclass, then:
20510 [temp.deduct.call]
20512 If they yield more than one possible deduced A, the type
20513 deduction fails.
20515 applies. */
20517 {
20520 }
20523 }
20524 }
20528 }
20530 /* Returns the level of DECL, which declares a template parameter. */
20532 static int
20534 {
20536 {
20546 }
20548 }
20550 /* Decide whether ARG can be unified with PARM, considering only the
20551 cv-qualifiers of each type, given STRICT as documented for unify.
20552 Returns nonzero iff the unification is OK on that basis. */
20554 static int
20556 {
20562 {
20563 /* Although a CVR qualifier is ignored when being applied to a
20564 substituted template parameter ([8.3.2]/1 for example), that
20565 does not allow us to unify "const T" with "int&" because both
20566 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20567 It is ok when we're allowing additional CV qualifiers
20568 at the outer level [14.8.2.1]/3,1st bullet. */
20578 }
20589 }
20591 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20592 void
20594 {
20598 {
20601 }
20602 else
20603 {
20606 }
20607 }
20609 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20610 do { \
20611 if (unify (TP, TA, P, A, S, EP)) \
20612 return 1; \
20613 } while (0)
20615 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20616 expansion at the end of PACKED_PARMS. Returns 0 if the type
20617 deduction succeeds, 1 otherwise. STRICT is the same as in
20618 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20619 function call argument list. We'll need to adjust the arguments to make them
20620 types. SUBR tells us if this is from a recursive call to
20621 type_unification_real, or for comparing two template argument
20622 lists. */
20624 static int
20628 {
20629 tree parm
20635 /* Add in any args remembered from an earlier partial instantiation. */
20643 /* Determine the parameter packs we will be deducing from the
20644 pattern, and record their current deductions. */
20647 {
20651 /* Only template parameter packs can be deduced, not e.g. function
20652 parameter packs or __bases or __integer_pack. */
20656 /* Determine the index and level of this parameter pack. */
20661 /* Keep track of the parameter packs and their corresponding
20662 argument packs. */
20665 }
20667 /* Loop through all of the arguments that have not yet been
20668 unified and unify each with the pattern. */
20670 {
20671 tree parm;
20675 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20676 or the element of its argument pack at the current index if
20677 this argument was explicitly specified. */
20679 {
20688 {
20691 }
20693 }
20695 /* If we had explicit template arguments, substitute them into the
20696 pattern before deduction. */
20698 {
20699 /* Some arguments might still be unspecified or dependent. */
20707 NULL_TREE);
20712 }
20713 else
20716 /* Unify the pattern with the current argument. */
20718 explain_p))
20721 /* For each parameter pack, collect the deduced value. */
20723 {
20729 }
20730 }
20732 /* Verify that the results of unification with the parameter packs
20733 produce results consistent with what we've seen before, and make
20734 the deduced argument packs available. */
20736 {
20743 /* By default keep the original deduced argument pack.
20744 If necessary, more specific code is going to update the
20745 resulting deduced argument later down in this function. */
20749 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20750 actually deduce anything. */
20758 {
20759 /* If we had fewer function args than explicit template args,
20760 just use the explicits. */
20765 }
20768 {
20769 tree result;
20770 /* Build the deduced *_ARGUMENT_PACK. */
20772 {
20775 }
20776 else
20781 /* Note the deduced argument packs for this parameter
20782 pack. */
20784 }
20788 {
20789 /* We only had the explicitly-provided arguments before, but
20790 now we have a complete set of arguments. */
20796 }
20797 else
20798 {
20804 /* Inconsistent unification of this parameter pack. */
20806 bad_old_arg,
20807 bad_new_arg);
20808 }
20809 }
20812 }
20814 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20815 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20816 parameters and return value are as for unify. */
20818 static int
20822 {
20823 tree parm_max;
20824 tree arg_max;
20828 /* Our representation of array types uses "N - 1" as the
20829 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20830 not an integer constant. We cannot unify arbitrarily
20831 complex expressions, so we eliminate the MINUS_EXPRs
20832 here. */
20836 {
20839 }
20843 {
20844 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20845 trying to unify the type of a variable with the type
20846 of a template parameter. For example:
20848 template <unsigned int N>
20849 void f (char (&) [N]);
20850 int g();
20851 void h(int i) {
20852 char a[g(i)];
20853 f(a);
20854 }
20856 Here, the type of the ARG will be "int [g(i)]", and
20857 may be a SAVE_EXPR, etc. */
20861 }
20863 /* If only one of the bounds used a MINUS_EXPR, compensate
20864 by adding one to the other bound. */
20867 integer_type_node,
20868 parm_max,
20869 integer_one_node);
20872 integer_type_node,
20873 arg_max,
20874 integer_one_node);
20878 }
20880 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20884 static pa_kind_t
20886 {
20895 else
20897 }
20899 /* Deduce the value of template parameters. TPARMS is the (innermost)
20900 set of template parameters to a template. TARGS is the bindings
20901 for those template parameters, as determined thus far; TARGS may
20902 include template arguments for outer levels of template parameters
20903 as well. PARM is a parameter to a template function, or a
20904 subcomponent of that parameter; ARG is the corresponding argument.
20905 This function attempts to match PARM with ARG in a manner
20906 consistent with the existing assignments in TARGS. If more values
20907 are deduced, then TARGS is updated.
20909 Returns 0 if the type deduction succeeds, 1 otherwise. The
20910 parameter STRICT is a bitwise or of the following flags:
20912 UNIFY_ALLOW_NONE:
20913 Require an exact match between PARM and ARG.
20914 UNIFY_ALLOW_MORE_CV_QUAL:
20915 Allow the deduced ARG to be more cv-qualified (by qualification
20916 conversion) than ARG.
20917 UNIFY_ALLOW_LESS_CV_QUAL:
20918 Allow the deduced ARG to be less cv-qualified than ARG.
20919 UNIFY_ALLOW_DERIVED:
20920 Allow the deduced ARG to be a template base class of ARG,
20921 or a pointer to a template base class of the type pointed to by
20922 ARG.
20923 UNIFY_ALLOW_INTEGER:
20924 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20925 case for more information.
20926 UNIFY_ALLOW_OUTER_LEVEL:
20927 This is the outermost level of a deduction. Used to determine validity
20928 of qualification conversions. A valid qualification conversion must
20929 have const qualified pointers leading up to the inner type which
20930 requires additional CV quals, except at the outer level, where const
20931 is not required [conv.qual]. It would be normal to set this flag in
20932 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20933 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20934 This is the outermost level of a deduction, and PARM can be more CV
20935 qualified at this point.
20936 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20937 This is the outermost level of a deduction, and PARM can be less CV
20938 qualified at this point. */
20940 static int
20943 {
20945 tree targ;
20946 tree tparm;
20948 tsubst_flags_t complain = (explain_p
20949 ? tf_warning_or_error
20952 /* I don't think this will do the right thing with respect to types.
20953 But the only case I've seen it in so far has been array bounds, where
20954 signedness is the only information lost, and I think that will be
20955 okay. */
20963 /* We can't deduce anything from this, but we might get all the
20964 template args from other function args. */
20970 /* If PARM uses template parameters, then we can't bail out here,
20971 even if ARG == PARM, since we won't record unifications for the
20972 template parameters. We might need them if we're trying to
20973 figure out which of two things is more specialized. */
20977 /* Handle init lists early, so the rest of the function can assume
20978 we're dealing with a type. */
20980 {
20985 /* Replace T with std::initializer_list<T> for deduction. */
20992 /* We can only deduce from an initializer list argument if the
20993 parameter is std::initializer_list or an array; otherwise this
20994 is a non-deduced context. */
20999 else
21000 {
21002 /* Deduction is defined in terms of a single type, so just punt
21003 on the (bizarre) std::initializer_list<T...>. */
21006 }
21009 {
21016 {
21020 /* It should only be possible to get here for a call. */
21022 elt_strict |= maybe_adjust_types_for_deduction
21025 }
21028 explain_p);
21029 }
21033 {
21034 /* Also deduce from the length of the initializer list. */
21041 }
21043 /* If the std::initializer_list<T> deduction worked, replace the
21044 deduced A with std::initializer_list<A>. */
21046 {
21051 }
21053 }
21055 /* If parm and arg aren't the same kind of thing (template, type, or
21056 expression), fail early. */
21060 /* Immediately reject some pairs that won't unify because of
21061 cv-qualification mismatches. */
21064 /* It is the elements of the array which hold the cv quals of an array
21065 type, and the elements might be template type parms. We'll check
21066 when we recurse. */
21068 /* We check the cv-qualifiers when unifying with template type
21069 parameters below. We want to allow ARG `const T' to unify with
21070 PARM `T' for example, when computing which of two templates
21071 is more specialized, for example. */
21085 {
21089 /* In a type which contains a nested-name-specifier, template
21090 argument values cannot be deduced for template parameters used
21091 within the nested-name-specifier. */
21103 /* The PARM is not one we're trying to unify. Just check
21104 to see if it matches ARG. */
21105 {
21110 else
21112 }
21119 /* Check for mixed types and values. */
21127 {
21130 {
21131 /* First try to match ARG directly. */
21133 explain_p);
21135 {
21136 /* Otherwise, look for a suitable base of ARG, as below. */
21143 }
21144 }
21145 /* ARG must be constructed from a template class or a template
21146 template parameter. */
21151 /* Deduce arguments T, i from TT<T> or TT<i>. */
21157 /* Fall through to deduce template name. */
21158 }
21162 {
21163 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21165 /* Simple cases: Value already set, does match or doesn't. */
21170 }
21171 else
21172 {
21173 /* If PARM is `const T' and ARG is only `int', we don't have
21174 a match unless we are allowing additional qualification.
21175 If ARG is `const int' and PARM is just `T' that's OK;
21176 that binds `const int' to `T'. */
21181 /* Consider the case where ARG is `const volatile int' and
21182 PARM is `const T'. Then, T should be `volatile int'. */
21183 arg = cp_build_qualified_type_real
21188 /* Simple cases: Value already set, does match or doesn't. */
21194 /* Make sure that ARG is not a variable-sized array. (Note
21195 that were talking about variable-sized arrays (like
21196 `int[n]'), rather than arrays of unknown size (like
21197 `int[]').) We'll get very confused by such a type since
21198 the bound of the array is not constant, and therefore
21199 not mangleable. Besides, such types are not allowed in
21200 ISO C++, so we can do as we please here. We do allow
21201 them for 'auto' deduction, since that isn't ABI-exposed. */
21205 /* Strip typedefs as in convert_template_argument. */
21207 }
21209 /* If ARG is a parameter pack or an expansion, we cannot unify
21210 against it unless PARM is also a parameter pack. */
21215 /* If the argument deduction results is a METHOD_TYPE,
21216 then there is a problem.
21217 METHOD_TYPE doesn't map to any real C++ type the result of
21218 the deduction can not be of that type. */
21232 {
21233 /* The PARM is not one we're trying to unify. Just check
21234 to see if it matches ARG. */
21240 }
21246 {
21250 /* We're deducing from an array bound, the type doesn't matter. */
21256 }
21258 /* [temp.deduct.type] If, in the declaration of a function template
21259 with a non-type template-parameter, the non-type
21260 template-parameter is used in an expression in the function
21261 parameter-list and, if the corresponding template-argument is
21262 deduced, the template-argument type shall match the type of the
21263 template-parameter exactly, except that a template-argument
21264 deduced from an array bound may be of any integral type.
21265 The non-type parameter might use already deduced type parameters. */
21268 /* We don't have enough levels of args to do any substitution. This
21270 else
21271 {
21277 {
21281 }
21282 }
21285 /* Template-parameter dependent expression. Just accept it for now.
21286 It will later be processed in convert_template_argument. */
21287 ;
21293 /* Convert the ARG to the type of PARM; the deduced non-type
21294 template argument must exactly match the types of the
21295 corresponding parameter. */
21298 {
21299 /* We haven't deduced the type of this parameter yet. */
21301 /* We deduce from array bounds in try_array_deduction. */
21303 {
21304 /* Deduce it from the non-type argument. */
21309 }
21310 else
21311 /* Try again later. */
21313 }
21314 else
21317 /* If ARG is a parameter pack or an expansion, we cannot unify
21318 against it unless PARM is also a parameter pack. */
21323 {
21326 }
21331 {
21332 /* A pointer-to-member constant can be unified only with
21333 another constant. */
21337 /* Just unify the class member. It would be useless (and possibly
21338 wrong, depending on the strict flags) to unify also
21339 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21340 arg refer to the same variable, even if through different
21341 classes. For instance:
21343 struct A { int x; };
21344 struct B : A { };
21346 Unification of &A::x and &B::x must succeed. */
21349 }
21352 {
21356 /* [temp.deduct.call]
21358 A can be another pointer or pointer to member type that can
21359 be converted to the deduced A via a qualification
21360 conversion (_conv.qual_).
21362 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21363 This will allow for additional cv-qualification of the
21364 pointed-to types if appropriate. */
21367 /* The derived-to-base conversion only persists through one
21368 level of pointers. */
21373 }
21405 /* We have already checked cv-qualification at the top of the
21406 function. */
21410 /* As far as unification is concerned, this wins. Later checks
21411 will invalidate it if necessary. */
21414 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21415 /* Type INTEGER_CST can come from ordinary constant template args. */
21427 {
21437 /* Check for pack expansions in the parameters. */
21439 {
21441 {
21443 /* We can unify against something with a trailing
21444 parameter pack. */
21446 else
21447 /* [temp.deduct.type]/9: If the template argument list of
21448 P contains a pack expansion that is not the last
21449 template argument, the entire template argument list
21450 is a non-deduced context. */
21452 }
21453 }
21455 /* If we don't have enough arguments to satisfy the parameters
21456 (not counting the pack expression at the end), or we have
21457 too many arguments for a parameter list that doesn't end in
21458 a pack expression, we can't unify. */
21464 /* Unify all of the parameters that precede the (optional)
21465 pack expression. */
21467 {
21472 }
21475 DEDUCE_EXACT,
21478 }
21486 {
21494 }
21499 {
21503 {
21504 /* First, we try to unify the PARM and ARG directly. */
21509 {
21510 /* Fallback to the special case allowed in
21511 [temp.deduct.call]:
21513 If P is a class, and P has the form
21514 template-id, then A can be a derived class of
21515 the deduced A. Likewise, if P is a pointer to
21516 a class of the form template-id, A can be a
21517 pointer to a derived class pointed to by the
21518 deduced A. */
21524 {
21525 /* Don't give the derived diagnostic if we're
21526 already dealing with the same template. */
21527 bool same_template
21533 }
21534 }
21535 }
21539 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21540 Then, we should unify `int' and `U'. */
21542 else
21543 /* There's no chance of unification succeeding. */
21548 }
21555 {
21558 tree a;
21564 /* CV qualifications for methods can never be deduced, they must
21565 match exactly. We need to check them explicitly here,
21566 because type_unification_real treats them as any other
21567 cv-qualified parameter. */
21569 && (!check_cv_quals_for_unify
21597 {
21609 }
21612 }
21615 /* Unify a pointer to member with a pointer to member function, which
21616 deduces the type of the member as a function type. */
21618 {
21619 /* Check top-level cv qualifiers */
21627 /* Determine the type of the function we are unifying against. */
21631 }
21650 /* Matched cases are handled by the ARG == PARM test above. */
21654 /* We might get a variable as a non-type template argument in parm if the
21655 corresponding parameter is type-dependent. Make any necessary
21656 adjustments based on whether arg is a reference. */
21660 {
21665 }
21666 /* Now use the normal expression code to check whether they match. */
21677 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21678 or UNDERLYING_TYPE nodes. */
21682 /* Unification fails if we hit an error node. */
21687 {
21697 }
21698 /* FALLTHRU */
21701 /* An unresolved overload is a nondeduced context. */
21705 expr:
21706 /* We must be looking at an expression. This can happen with
21707 something like:
21709 template <int I>
21710 void foo(S<I>, S<I + 2>);
21712 This is a "nondeduced context":
21714 [deduct.type]
21716 The nondeduced contexts are:
21718 --A type that is a template-id in which one or more of
21719 the template-arguments is an expression that references
21720 a template-parameter.
21722 In these cases, we assume deduction succeeded, but don't
21723 actually infer any unifications. */
21728 else
21730 }
21731 }
21732 #undef RECUR_AND_CHECK_FAILURE
21733 \f
21734 /* Note that DECL can be defined in this translation unit, if
21735 required. */
21737 static void
21739 {
21740 tree clone;
21744 }
21746 /* Called if RESULT is explicitly instantiated, or is a member of an
21747 explicitly instantiated class. */
21749 void
21751 {
21754 /* If this entity has already been written out, it's too late to
21755 make any modifications. */
21759 /* For anonymous namespace we don't need to do anything. */
21761 {
21764 }
21767 /* The TREE_PUBLIC flag for function declarations will have been
21768 set correctly by tsubst. */
21771 /* This might have been set by an earlier implicit instantiation. */
21776 else
21777 {
21780 /* Always make artificials weak. */
21783 /* For WIN32 we also want to put explicit instantiations in
21784 linkonce sections. */
21787 }
21789 /* If EXTERN_P, then this function will not be emitted -- unless
21790 followed by an explicit instantiation, at which point its linkage
21791 will be adjusted. If !EXTERN_P, then this function will be
21792 emitted here. In neither circumstance do we want
21793 import_export_decl to adjust the linkage. */
21795 }
21797 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21798 important template arguments. If any are missing, we check whether
21799 they're important by using error_mark_node for substituting into any
21800 args that were used for partial ordering (the ones between ARGS and END)
21801 and seeing if it bubbles up. */
21803 static bool
21805 {
21810 {
21813 }
21815 {
21819 }
21821 }
21823 /* Given two function templates PAT1 and PAT2, return:
21825 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21826 -1 if PAT2 is more specialized than PAT1.
21827 0 if neither is more specialized.
21829 LEN indicates the number of parameters we should consider
21830 (defaulted parameters should not be considered).
21832 The 1998 std underspecified function template partial ordering, and
21833 DR214 addresses the issue. We take pairs of arguments, one from
21834 each of the templates, and deduce them against each other. One of
21835 the templates will be more specialized if all the *other*
21836 template's arguments deduce against its arguments and at least one
21837 of its arguments *does* *not* deduce against the other template's
21838 corresponding argument. Deduction is done as for class templates.
21839 The arguments used in deduction have reference and top level cv
21840 qualifiers removed. Iff both arguments were originally reference
21841 types *and* deduction succeeds in both directions, an lvalue reference
21842 wins against an rvalue reference and otherwise the template
21843 with the more cv-qualified argument wins for that pairing (if
21844 neither is more cv-qualified, they both are equal). Unlike regular
21845 deduction, after all the arguments have been deduced in this way,
21846 we do *not* verify the deduced template argument values can be
21847 substituted into non-deduced contexts.
21849 The logic can be a bit confusing here, because we look at deduce1 and
21850 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21851 can find template arguments for pat1 to make arg1 look like arg2, that
21852 means that arg2 is at least as specialized as arg1. */
21854 int
21856 {
21869 /* Remove the this parameter from non-static member functions. If
21870 one is a non-static member function and the other is not a static
21871 member function, remove the first parameter from that function
21872 also. This situation occurs for operator functions where we
21873 locate both a member function (with this pointer) and non-member
21874 operator (with explicit first operand). */
21876 {
21881 }
21883 {
21886 {
21887 len--;
21889 }
21890 }
21892 /* If only one is a conversion operator, they are unordered. */
21896 /* Consider the return type for a conversion function */
21898 {
21901 len++;
21902 }
21904 processing_template_decl++;
21910 /* Stop when an ellipsis is seen. */
21912 {
21923 {
21924 /* When both arguments are pack expansions, we need only
21925 unify the patterns themselves. */
21929 /* This is the last comparison we need to do. */
21931 }
21933 /* DR 1847: If a particular P contains no template-parameters that
21934 participate in template argument deduction, that P is not used to
21935 determine the ordering. */
21941 {
21945 }
21948 {
21952 }
21958 {
21964 /* Setup the parameter vector, which contains only ARG1. */
21967 /* Setup the argument vector, which contains the remaining
21968 arguments. */
21977 /* We cannot deduce in the other direction, because ARG1 is
21978 a pack expansion but ARG2 is not. */
21980 }
21982 {
21988 /* Setup the parameter vector, which contains only ARG1. */
21991 /* Setup the argument vector, which contains the remaining
21992 arguments. */
22001 /* We cannot deduce in the other direction, because ARG2 is
22002 a pack expansion but ARG1 is not.*/
22004 }
22006 else
22007 {
22008 /* The normal case, where neither argument is a pack
22009 expansion. */
22016 }
22018 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22019 arg2, then arg2 is not as specialized as arg1. */
22025 /* "If, for a given type, deduction succeeds in both directions
22026 (i.e., the types are identical after the transformations above)
22027 and both P and A were reference types (before being replaced with
22028 the type referred to above):
22029 - if the type from the argument template was an lvalue reference and
22030 the type from the parameter template was not, the argument type is
22031 considered to be more specialized than the other; otherwise,
22032 - if the type from the argument template is more cv-qualified
22033 than the type from the parameter template (as described above),
22034 the argument type is considered to be more specialized than the other;
22035 otherwise,
22036 - neither type is more specialized than the other." */
22039 {
22041 {
22044 else
22046 }
22048 {
22053 }
22054 }
22057 /* We've failed to deduce something in either direction.
22058 These must be unordered. */
22061 next:
22065 /* We have already processed all of the arguments in our
22066 handing of the pack expansion type. */
22071 }
22073 /* "In most cases, all template parameters must have values in order for
22074 deduction to succeed, but for partial ordering purposes a template
22075 parameter may remain without a value provided it is not used in the
22076 types being used for partial ordering."
22078 Thus, if we are missing any of the targs1 we need to substitute into
22079 origs1, then pat2 is not as specialized as pat1. This can happen when
22080 there is a nondeduced context. */
22086 processing_template_decl--;
22088 /* If both deductions succeed, the partial ordering selects the more
22089 constrained template. */
22091 {
22096 }
22098 /* All things being equal, if the next argument is a pack expansion
22099 for one function but not for the other, prefer the
22100 non-variadic function. FIXME this is bogus; see c++/41958. */
22104 {
22107 }
22113 else
22115 }
22117 /* Determine which of two partial specializations of TMPL is more
22118 specialized.
22120 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22121 to the first partial specialization. The TREE_PURPOSE is the
22122 innermost set of template parameters for the partial
22123 specialization. PAT2 is similar, but for the second template.
22125 Return 1 if the first partial specialization is more specialized;
22126 -1 if the second is more specialized; 0 if neither is more
22127 specialized.
22129 See [temp.class.order] for information about determining which of
22130 two templates is more specialized. */
22132 static int
22134 {
22135 tree targs;
22144 /* Just like what happens for functions, if we are ordering between
22145 different template specializations, we may encounter dependent
22146 types in the arguments, and we need our dependency check functions
22147 to behave correctly. */
22151 {
22154 }
22158 {
22161 }
22164 /* If both deductions succeed, the partial ordering selects the more
22165 constrained template. */
22169 /* In the case of a tie where at least one of the templates
22170 has a parameter pack at the end, the template with the most
22171 non-packed parameters wins. */
22173 && any_deductions
22176 {
22182 /* We don't count the pack expansion at the end. */
22192 }
22195 }
22197 /* Return the template arguments that will produce the function signature
22198 DECL from the function template FN, with the explicit template
22199 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22200 also match. Return NULL_TREE if no satisfactory arguments could be
22201 found. */
22203 static tree
22205 {
22209 tree decl_arg_types;
22212 tree arg;
22216 /* Never do unification on the 'this' parameter. */
22237 }
22239 /* Return the innermost template arguments that, when applied to a partial
22240 specialization SPEC_TMPL of TMPL, yield the ARGS.
22242 For example, suppose we have:
22244 template <class T, class U> struct S {};
22245 template <class T> struct S<T*, int> {};
22247 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22248 partial specialization and the ARGS will be {double*, int}. The resulting
22249 vector will be {double}, indicating that `T' is bound to `double'. */
22251 static tree
22253 {
22255 tree spec_args
22258 tree deduced_args;
22259 tree innermost_deduced_args;
22263 {
22267 innermost_deduced_args);
22268 }
22269 else
22273 again:
22282 {
22284 {
22290 }
22292 }
22296 {
22299 }
22301 /* Verify that nondeduced template arguments agree with the type
22302 obtained from argument deduction.
22304 For example:
22306 struct A { typedef int X; };
22307 template <class T, class U> struct C {};
22308 template <class T> struct C<T, typename T::X> {};
22310 Then with the instantiation `C<A, int>', we can deduce that
22311 `T' is `A' but unify () does not check whether `typename T::X'
22312 is `int'. */
22323 /* We only need to check the innermost arguments; the other
22324 arguments will always agree. */
22329 /* Now that we have bindings for all of the template arguments,
22330 ensure that the arguments deduced for the template template
22331 parameters have compatible template parameter lists. See the use
22332 of template_template_parm_bindings_ok_p in fn_type_unification
22333 for more information. */
22338 }
22340 // Compare two function templates T1 and T2 by deducing bindings
22341 // from one against the other. If both deductions succeed, compare
22342 // constraints to see which is more constrained.
22343 static int
22345 {
22350 {
22353 }
22356 {
22359 }
22361 // If both deductions succeed, then one may be more constrained.
22366 }
22368 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22369 Return the TREE_LIST node with the most specialized template, if
22370 any. If there is no most specialized template, the error_mark_node
22371 is returned.
22373 Note that this function does not look at, or modify, the
22374 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22375 returned is one of the elements of INSTANTIATIONS, callers may
22376 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22377 and retrieve it from the value returned. */
22379 tree
22381 {
22388 {
22394 {
22395 /* Equally specialized, move to next function. If there
22396 is no next function, nothing's most specialized. */
22401 }
22402 }
22405 /* Now verify that champ is better than everything earlier in the
22406 instantiation list. */
22409 {
22412 }
22413 }
22415 processing_template_decl--;
22421 }
22423 /* If DECL is a specialization of some template, return the most
22424 general such template. Otherwise, returns NULL_TREE.
22426 For example, given:
22428 template <class T> struct S { template <class U> void f(U); };
22430 if TMPL is `template <class U> void S<int>::f(U)' this will return
22431 the full template. This function will not trace past partial
22432 specializations, however. For example, given in addition:
22434 template <class T> struct S<T*> { template <class U> void f(U); };
22436 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22437 `template <class T> template <class U> S<T*>::f(U)'. */
22439 tree
22441 {
22443 {
22446 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22447 template friend, or a FIELD_DECL for a capture pack. */
22450 }
22452 /* Look for more and more general templates. */
22454 {
22455 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22456 (See cp-tree.h for details.) */
22465 /* Stop if we run into an explicitly specialized class template. */
22472 }
22475 }
22477 /* Return the most specialized of the template partial specializations
22478 which can produce TARGET, a specialization of some class or variable
22479 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22480 a TEMPLATE_DECL node corresponding to the partial specialization, while
22481 the TREE_PURPOSE is the set of template arguments that must be
22482 substituted into the template pattern in order to generate TARGET.
22484 If the choice of partial specialization is ambiguous, a diagnostic
22485 is issued, and the error_mark_node is returned. If there are no
22486 partial specializations matching TARGET, then NULL_TREE is
22487 returned, indicating that the primary template should be used. */
22489 static tree
22491 {
22493 tree t;
22494 tree champ;
22501 {
22505 }
22507 {
22510 }
22512 {
22516 }
22517 else
22522 /* For determining which partial specialization to use, only the
22523 innermost args are interesting. */
22525 {
22528 }
22531 {
22532 tree spec_args;
22536 {
22537 /* Substitute in the template args from the enclosing class. */
22541 }
22548 {
22552 /* Keep the candidate only if the constraints are satisfied,
22553 or if we're not compiling with concepts. */
22556 {
22559 }
22560 }
22561 }
22571 {
22574 ;
22575 else
22576 {
22578 {
22581 {
22584 }
22585 }
22587 }
22588 }
22592 {
22595 {
22598 }
22599 }
22602 {
22609 else
22613 {
22618 }
22621 }
22624 }
22626 /* Explicitly instantiate DECL. */
22628 void
22630 {
22635 /* An error occurred, for which grokdeclarator has already issued
22636 an appropriate message. */
22639 {
22642 }
22648 {
22649 /* There is an asymmetry here in the way VAR_DECLs and
22650 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22651 the latter, the DECL we get back will be marked as a
22652 template instantiation, and the appropriate
22653 DECL_TEMPLATE_INFO will be set up. This does not happen for
22654 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22655 should handle VAR_DECLs as it currently handles
22656 FUNCTION_DECLs. */
22658 {
22661 }
22664 {
22667 }
22669 {
22674 }
22675 }
22677 {
22680 }
22681 else
22684 /* Check for various error cases. Note that if the explicit
22685 instantiation is valid the RESULT will currently be marked as an
22686 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22687 until we get here. */
22690 {
22691 /* DR 259 [temp.spec].
22693 Both an explicit instantiation and a declaration of an explicit
22694 specialization shall not appear in a program unless the explicit
22695 instantiation follows a declaration of the explicit specialization.
22697 For a given set of template parameters, if an explicit
22698 instantiation of a template appears after a declaration of an
22699 explicit specialization for that template, the explicit
22700 instantiation has no effect. */
22702 }
22704 {
22705 /* [temp.spec]
22707 No program shall explicitly instantiate any template more
22708 than once.
22710 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22711 the first instantiation was `extern' and the second is not,
22712 and EXTERN_P for the opposite case. */
22715 /* If an "extern" explicit instantiation follows an ordinary
22716 explicit instantiation, the template is instantiated. */
22719 }
22721 {
22724 }
22726 {
22729 }
22732 ;
22734 {
22737 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22740 }
22741 else
22749 }
22751 static void
22753 {
22759 {
22762 }
22763 }
22765 /* Called from do_type_instantiation through binding_table_foreach to
22766 do recursive instantiation for the type bound in ENTRY. */
22767 static void
22769 {
22775 }
22777 /* Perform an explicit instantiation of template class T. STORAGE, if
22778 non-null, is the RID for extern, inline or static. COMPLAIN is
22779 nonzero if this is called from the parser, zero if called recursively,
22780 since the standard is unclear (as detailed below). */
22782 void
22784 {
22794 {
22795 tree tmpl =
22799 else
22802 }
22807 {
22810 t);
22812 }
22815 {
22817 {
22819 {
22822 "ISO C++ 1998 forbids the use of %<extern%> on "
22824 }
22825 else
22827 "ISO C++ forbids the use of %qE"
22829 }
22837 else
22838 {
22840 storage);
22842 }
22843 }
22846 {
22847 /* DR 259 [temp.spec].
22849 Both an explicit instantiation and a declaration of an explicit
22850 specialization shall not appear in a program unless the explicit
22851 instantiation follows a declaration of the explicit specialization.
22853 For a given set of template parameters, if an explicit
22854 instantiation of a template appears after a declaration of an
22855 explicit specialization for that template, the explicit
22856 instantiation has no effect. */
22858 }
22860 {
22861 /* [temp.spec]
22863 No program shall explicitly instantiate any template more
22864 than once.
22866 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22867 instantiation was `extern'. If EXTERN_P then the second is.
22868 These cases are OK. */
22875 /* If we've already instantiated the template, just return now. */
22878 }
22886 /* In contrast to implicit instantiation, where only the
22887 declarations, and not the definitions, of members are
22888 instantiated, we have here:
22890 [temp.explicit]
22892 The explicit instantiation of a class template specialization
22893 implies the instantiation of all of its members not
22894 previously explicitly specialized in the translation unit
22895 containing the explicit instantiation.
22897 Of course, we can't instantiate member template classes, since we
22898 don't have any arguments for them. Note that the standard is
22899 unclear on whether the instantiation of the members are
22900 *explicit* instantiations or not. However, the most natural
22901 interpretation is that it should be an explicit
22902 instantiation. */
22906 && !static_p
22909 {
22914 }
22919 }
22921 /* Given a function DECL, which is a specialization of TMPL, modify
22922 DECL to be a re-instantiation of TMPL with the same template
22923 arguments. TMPL should be the template into which tsubst'ing
22924 should occur for DECL, not the most general template.
22926 One reason for doing this is a scenario like this:
22928 template <class T>
22929 void f(const T&, int i);
22931 void g() { f(3, 7); }
22933 template <class T>
22934 void f(const T& t, const int i) { }
22936 Note that when the template is first instantiated, with
22937 instantiate_template, the resulting DECL will have no name for the
22938 first parameter, and the wrong type for the second. So, when we go
22939 to instantiate the DECL, we regenerate it. */
22941 static void
22943 {
22944 /* The arguments used to instantiate DECL, from the most general
22945 template. */
22946 tree code_pattern;
22950 /* Make sure that we can see identifiers, and compute access
22951 correctly. */
22955 {
22956 tree decl_parm;
22957 tree pattern_parm;
22958 tree specs;
22972 specs);
22974 /* Merge parameter declarations. */
22977 pattern_parm
22981 {
22982 tree parm_type;
22983 tree attributes;
22988 NULL_TREE);
22994 {
22997 }
23000 }
23001 /* Merge any parameters that match with the function parameter
23002 pack. */
23004 {
23006 tree expanded_types;
23007 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23008 the parameters in this function parameter pack. */
23013 {
23014 tree parm_type;
23015 tree attributes;
23018 /* Rename the parameter to include the index. */
23027 {
23030 }
23032 }
23033 }
23034 /* Merge additional specifiers from the CODE_PATTERN. */
23038 }
23040 {
23050 }
23051 else
23055 }
23057 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23058 substituted to get DECL. */
23060 tree
23062 {
23065 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23066 for the instantiation. This is not always the most general
23067 template. Consider, for example:
23069 template <class T>
23070 struct S { template <class U> void f();
23071 template <> void f<int>(); };
23073 and an instantiation of S<double>::f<int>. We want TD to be the
23074 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23076 more general template. */
23078 /* We must also deal with friend templates. Given:
23080 template <class T> struct S {
23081 template <class U> friend void f() {};
23082 };
23084 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23085 so far as the language is concerned, but that's still
23086 where we get the pattern for the instantiation from. On
23087 other hand, if the definition comes outside the class, say:
23089 template <class T> struct S {
23090 template <class U> friend void f();
23091 };
23092 template <class U> friend void f() {}
23094 we don't need to look any further. That's what the check for
23095 DECL_INITIAL is for. */
23099 {
23100 /* The present template, TD, should not be a definition. If it
23101 were a definition, we should be using it! Note that we
23102 cannot restructure the loop to just keep going until we find
23103 a template with a definition, since that might go too far if
23104 a specialization was declared, but not defined. */
23106 /* Fetch the more general template. */
23108 }
23111 }
23113 /* Returns true if we need to instantiate this template instance even if we
23114 know we aren't going to emit it. */
23116 bool
23118 {
23119 /* We always instantiate inline functions so that we can inline them. An
23120 explicit instantiation declaration prohibits implicit instantiation of
23121 non-inline functions. With high levels of optimization, we would
23122 normally inline non-inline functions -- but we're not allowed to do
23123 that for "extern template" functions. Therefore, we check
23124 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23128 /* And we need to instantiate static data members so that
23129 their initializers are available in integral constant
23130 expressions. */
23133 }
23135 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23136 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23137 error, true otherwise. */
23139 bool
23141 {
23144 /* Don't instantiate a noexcept-specification from template context. */
23159 {
23165 {
23166 /* If hash_set::add returns true, the element was already there. */
23171 fn);
23173 }
23175 {
23190 }
23191 else
23201 }
23204 {
23207 else
23209 }
23212 }
23214 /* We're starting to process the function INST, an instantiation of PATTERN;
23215 add their parameters to local_specializations. */
23217 static void
23219 {
23223 {
23227 }
23229 {
23231 {
23234 }
23235 else
23236 {
23237 /* Register the (value) argument pack as a specialization of
23238 TMPL_PARM, then move on. */
23241 }
23242 }
23244 }
23246 /* Produce the definition of D, a _DECL generated from a template. If
23247 DEFER_OK is true, then we don't have to actually do the
23248 instantiation now; we just have to do it sometime. Normally it is
23249 an error if this is an explicit instantiation but D is undefined.
23250 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23251 instantiated class template. */
23253 tree
23255 {
23257 tree gen_args;
23258 tree args;
23259 tree td;
23260 tree code_pattern;
23261 tree spec;
23262 tree gen_tmpl;
23270 /* This function should only be used to instantiate templates for
23271 functions and static member variables. */
23274 /* A concept is never instantiated. */
23277 /* Variables are never deferred; if instantiation is required, they
23278 are instantiated right away. That allows for better code in the
23279 case that an expression refers to the value of the variable --
23280 if the variable has a constant value the referring expression can
23281 take advantage of that fact. */
23285 /* Don't instantiate cloned functions. Instead, instantiate the
23286 functions they cloned. */
23294 /* D has already been instantiated or explicitly specialized, so
23295 there's nothing for us to do here.
23297 It might seem reasonable to check whether or not D is an explicit
23298 instantiation, and, if so, stop here. But when an explicit
23299 instantiation is deferred until the end of the compilation,
23300 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23301 the instantiation. */
23304 /* Check to see whether we know that this template will be
23305 instantiated in some other file, as with "extern template"
23306 extension. */
23309 /* In general, we do not instantiate such templates. */
23317 /* We should already have the extra args. */
23320 /* And what's in the hash table should match D. */
23324 /* This needs to happen before any tsubsting. */
23330 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23331 for the instantiation. */
23336 {
23337 /* Look up an explicit specialization, if any. */
23341 {
23344 }
23345 }
23349 /* We should never be trying to instantiate a member of a class
23350 template or partial specialization. */
23355 /* In the case of a friend template whose definition is provided
23356 outside the class, we may have too many arguments. Drop the
23357 ones we don't need. The same is true for specializations. */
23358 args = get_innermost_template_args
23362 {
23368 }
23369 else
23370 {
23375 else
23377 }
23379 /* We may be in the middle of deferred access check. Disable it now. */
23382 /* Unless an explicit instantiation directive has already determined
23383 the linkage of D, remember that a definition is available for
23384 this entity. */
23394 /* If D is a member of an explicitly instantiated class template,
23395 and no definition is available, treat it like an implicit
23396 instantiation. */
23399 {
23400 /* Leave linkage flags alone on instantiations with anonymous
23401 visibility. */
23403 {
23406 }
23408 }
23410 /* Defer all other templates, unless we have been explicitly
23411 forbidden from doing so. */
23413 template. */
23414 ! pattern_defined
23415 /* If it's OK to postpone instantiation, do so. */
23416 || defer_ok
23417 /* If this is a static data member that will be defined
23418 elsewhere, we don't want to instantiate the entire data
23419 member, but we do want to instantiate the initializer so that
23420 we can substitute that elsewhere. */
23422 /* Handle here a deleted function too, avoid generating
23423 its body (c++/61080). */
23425 {
23426 /* The definition of the static data member is now required so
23427 we must substitute the initializer. */
23431 {
23432 tree ns;
23433 tree init;
23442 args,
23445 /* If instantiating the initializer involved instantiating this
23446 again, don't call cp_finish_decl twice. */
23448 {
23449 /* Make sure the initializer is still constant, in case of
23450 circular dependency (template/instantiate6.C). */
23451 const_init
23455 LOOKUP_ONLYCONVERTING);
23456 }
23460 }
23462 /* We restore the source position here because it's used by
23463 add_pending_template. */
23469 /* [temp.explicit]
23471 The definition of a non-exported function template, a
23472 non-exported member function template, or a non-exported
23473 member function or static data member of a class template
23474 shall be present in every translation unit in which it is
23475 explicitly instantiated. */
23479 /* If we're in unevaluated context, we just wanted to get the
23480 constant value; this isn't an odr use, so don't queue
23481 a full instantiation. */
23484 /* ??? Historically, we have instantiated inline functions, even
23485 when marked as "extern template". */
23489 }
23490 /* Tell the repository that D is available in this translation unit
23491 -- and see if it is supposed to be instantiated here. */
23493 {
23494 /* In a PCH file, despite the fact that the repository hasn't
23495 requested instantiation in the PCH it is still possible that
23496 an instantiation will be required in a file that includes the
23497 PCH. */
23500 /* Instantiate inline functions so that the inliner can do its
23501 job, even though we'll not be emitting a copy of this
23502 function. */
23505 }
23508 tree fn_context;
23511 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23522 else
23523 {
23527 }
23529 /* Mark D as instantiated so that recursive calls to
23530 instantiate_decl do not try to instantiate it again. */
23533 /* Regenerate the declaration in case the template has been modified
23534 by a subsequent redeclaration. */
23537 /* We already set the file and line above. Reset them now in case
23538 they changed as a result of calling regenerate_decl_from_template. */
23542 {
23543 tree init;
23546 /* Clear out DECL_RTL; whatever was there before may not be right
23547 since we've reset the type of the declaration. */
23551 /* The initializer is placed in DECL_INITIAL by
23552 regenerate_decl_from_template so we don't need to
23553 push/pop_access_scope again here. Pull it out so that
23554 cp_finish_decl can process it. */
23559 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23560 initializer. That function will defer actual emission until
23561 we have a chance to determine linkage. */
23564 /* Enter the scope of D so that access-checking works correctly. */
23577 }
23581 {
23582 /* Set up the list of local specializations. */
23586 /* Set up context. */
23590 else
23593 /* Some typedefs referenced from within the template code need to be
23594 access checked at template instantiation time, i.e now. These
23595 types were added to the template at parsing time. Let's get those
23596 and perform the access checks then. */
23598 args);
23600 /* Create substitution entries for the parameters. */
23603 /* Substitute into the body of the function. */
23607 else
23608 {
23613 /* Set the current input_location to the end of the function
23614 so that finish_function knows where we are. */
23615 input_location
23618 /* Remember if we saw an infinite loop in the template. */
23619 current_function_infinite_loop
23621 }
23623 /* Finish the function. */
23627 else
23628 {
23631 }
23635 }
23637 /* We're not deferring instantiation any more. */
23642 else
23648 out:
23657 }
23659 /* Run through the list of templates that we wish we could
23660 instantiate, and instantiate any we can. RETRIES is the
23661 number of times we retry pending template instantiation. */
23663 void
23665 {
23669 /* Instantiating templates may trigger vtable generation. This in turn
23670 may require further template instantiations. We place a limit here
23671 to avoid infinite loop. */
23673 {
23677 "template instantiation depth exceeds maximum of %d"
23678 " instantiating %q+D, possibly from virtual table generation"
23682 /* Pretend that we defined it. */
23685 }
23687 do
23688 {
23693 {
23698 {
23700 {
23715 }
23718 }
23719 else
23720 {
23723 {
23724 instantiation
23730 }
23734 }
23737 /* If INSTANTIATION has been instantiated, then we don't
23738 need to consider it again in the future. */
23740 else
23741 {
23744 }
23747 }
23749 }
23753 }
23755 /* Substitute ARGVEC into T, which is a list of initializers for
23756 either base class or a non-static data member. The TREE_PURPOSEs
23757 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23758 instantiate_decl. */
23760 static tree
23762 {
23767 {
23768 tree decl;
23769 tree init;
23775 {
23776 tree expr;
23777 tree arg;
23779 /* Expand the base class expansion type into separate base
23780 classes. */
23782 tf_warning_or_error,
23783 NULL_TREE);
23787 /* We'll be building separate TREE_LISTs of arguments for
23788 each base. */
23794 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23795 expand each argument in the TREE_VALUE of t. */
23802 /* VOID_TYPE_NODE is used to indicate
23803 value-initialization. */
23804 {
23807 }
23808 else
23809 {
23810 /* Substitute parameter packs into each argument in the
23811 TREE_LIST. */
23814 {
23815 tree expanded_exprs;
23817 /* Expand the argument. */
23819 expanded_exprs
23821 tf_warning_or_error,
23822 NULL_TREE);
23826 /* Prepend each of the expanded expressions to the
23827 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23829 {
23834 }
23835 }
23838 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23839 since we built them backwards. */
23841 {
23844 }
23845 }
23846 }
23849 {
23851 {
23855 }
23856 else
23857 {
23858 tree tmp;
23873 /* If we had an initializer but it instantiated to nothing,
23874 value-initialize the object. This will only occur when
23875 the initializer was a pack expansion where the parameter
23876 packs used in that expansion were of length zero. */
23879 }
23883 {
23885 decl);
23887 }
23888 /* Look for a target constructor. */
23892 {
23895 {
23899 }
23901 }
23904 {
23908 }
23909 }
23910 }
23912 }
23914 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23916 static void
23918 {
23923 else
23925 }
23927 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23928 is the instantiation (which should have been created with
23929 start_enum) and ARGS are the template arguments to use. */
23931 static void
23933 {
23934 tree e;
23940 {
23941 tree value;
23942 tree decl;
23945 /* Note that in a template enum, the TREE_VALUE is the
23946 CONST_DECL, not the corresponding INTEGER_CST. */
23951 /* Give this enumeration constant the correct access. */
23954 /* Actually build the enumerator itself. Here we're assuming that
23955 enumerators can't have dependent attributes. */
23958 }
23968 }
23970 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23971 its type -- but without substituting the innermost set of template
23972 arguments. So, innermost set of template parameters will appear in
23973 the type. */
23975 tree
23977 {
23978 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23980 }
23982 /* Return truthvalue if we're processing a template different from
23983 the last one involved in diagnostics. */
23984 bool
23986 {
23988 }
23990 /* Remember current template involved in diagnostics. */
23991 void
23993 {
23995 }
23999 {
24001 }
24003 /* Return TRUE if current_function_decl is being instantiated, false
24004 otherwise. */
24006 bool
24008 {
24011 }
24013 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24014 type. Return false for ok, true for disallowed. Issue error and
24015 inform messages under control of COMPLAIN. */
24017 static bool
24019 {
24037 /* A bound template template parm could later be instantiated to have a valid
24038 nontype parm type via an alias template. */
24044 {
24047 else
24049 type);
24050 }
24052 }
24054 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24055 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24057 static bool
24059 {
24060 tree scope;
24062 /* [temp.dep.type]
24064 A type is dependent if it is:
24066 -- a template parameter. Template template parameters are types
24067 for us (since TYPE_P holds true for them) so we handle
24068 them here. */
24072 /* -- a qualified-id with a nested-name-specifier which contains a
24073 class-name that names a dependent type or whose unqualified-id
24074 names a dependent type. */
24078 /* An alias template specialization can be dependent even if the
24079 resulting type is not. */
24083 /* -- a cv-qualified type where the cv-unqualified type is
24084 dependent.
24085 No code is necessary for this bullet; the code below handles
24086 cv-qualified types, and we don't want to strip aliases with
24087 TYPE_MAIN_VARIANT because of DR 1558. */
24088 /* -- a compound type constructed from any dependent type. */
24098 {
24099 tree arg_type;
24104 arg_type;
24109 /* A value-dependent noexcept-specifier makes the type dependent. */
24112 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24113 affect overload resolution and treating it as dependent breaks
24114 things. */
24119 }
24120 /* -- an array type constructed from any dependent type or whose
24121 size is specified by a constant expression that is
24122 value-dependent.
24124 We checked for type- and value-dependence of the bounds in
24125 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24127 {
24132 }
24134 /* -- a template-id in which either the template name is a template
24135 parameter ... */
24138 /* ... or any of the template arguments is a dependent type or
24139 an expression that is type-dependent or value-dependent. */
24141 && (any_dependent_template_arguments_p
24145 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24146 dependent; if the argument of the `typeof' expression is not
24147 type-dependent, then it should already been have resolved. */
24153 /* A template argument pack is dependent if any of its packed
24154 arguments are. */
24156 {
24162 }
24164 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24165 be template parameters. */
24172 /* The standard does not specifically mention types that are local
24173 to template functions or local classes, but they should be
24174 considered dependent too. For example:
24176 template <int I> void f() {
24177 enum E { a = I };
24178 S<sizeof (E)> s;
24179 }
24181 The size of `E' cannot be known until the value of `I' has been
24182 determined. Therefore, `E' must be considered dependent. */
24186 /* Don't use type_dependent_expression_p here, as it can lead
24187 to infinite recursion trying to determine whether a lambda
24188 nested in a lambda is dependent (c++/47687). */
24192 && (any_dependent_template_arguments_p
24196 /* Other types are non-dependent. */
24198 }
24200 /* Returns TRUE if TYPE is dependent, in the sense of
24201 [temp.dep.type]. Note that a NULL type is considered dependent. */
24203 bool
24205 {
24206 /* If there are no template parameters in scope, then there can't be
24207 any dependent types. */
24209 {
24210 /* If we are not processing a template, then nobody should be
24211 providing us with a dependent type. */
24215 }
24217 /* If the type is NULL, we have not computed a type for the entity
24218 in question; in that case, the type is dependent. */
24222 /* Erroneous types can be considered non-dependent. */
24226 /* Getting here with global_type_node means we improperly called this
24227 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24230 /* If we have not already computed the appropriate value for TYPE,
24231 do so now. */
24233 {
24236 }
24239 }
24241 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24242 lookup. In other words, a dependent type that is not the current
24243 instantiation. */
24245 bool
24247 {
24250 }
24252 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24253 an unknown base of 'this' (and is therefore instantiation-dependent). */
24255 static bool
24257 {
24274 }
24276 /* T is a SCOPE_REF; return whether we need to consider it
24277 instantiation-dependent so that we can check access at instantiation
24278 time even though we know which member it resolves to. */
24280 static bool
24282 {
24289 else
24291 }
24293 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24294 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24295 expression. */
24297 /* Note that this predicate is not appropriate for general expressions;
24298 only constant expressions (that satisfy potential_constant_expression)
24299 can be tested for value dependence. */
24301 bool
24303 {
24307 /* A type-dependent expression is also value-dependent. */
24312 {
24314 /* A dependent member function of the current instantiation. */
24318 /* A dependent member function of the current instantiation. */
24325 /* A name that has not been looked up -- must be dependent. */
24329 /* A non-type template parm. */
24333 /* A non-type template parm. */
24339 /* A constant with literal type and is initialized
24340 with an expression that is value-dependent. */
24342 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24346 {
24350 }
24359 /* These expressions are value-dependent if the type to which
24360 the cast occurs is dependent or the expression being casted
24361 is value-dependent. */
24362 {
24368 /* A functional cast has a list of operands. */
24371 {
24372 /* If there are no operands, it must be an expression such
24373 as "int()". This should not happen for aggregate types
24374 because it would form non-constant expressions. */
24379 }
24385 }
24390 /* FALLTHRU */
24393 /* A `sizeof' expression is value-dependent if the operand is
24394 type-dependent or is a pack expansion. */
24403 /* An 'encode' expression is value-dependent if the operand is
24404 type-dependent. */
24413 /* All instantiation-dependent expressions should also be considered
24414 value-dependent. */
24422 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24423 is value-dependent. */
24424 {
24433 }
24436 {
24453 }
24464 {
24468 }
24471 /* Treat all requires-expressions as value-dependent so
24472 we don't try to fold them. */
24479 {
24486 {
24488 /* In a call to a constexpr member function, look through the
24489 implicit ADDR_EXPR on the object argument so that it doesn't
24490 cause the call to be considered value-dependent. We also
24491 look through it in potential_constant_expression. */
24498 }
24500 }
24506 {
24508 tree val;
24515 }
24518 /* Treat a GNU statement expression as dependent to avoid crashing
24519 under instantiate_non_dependent_expr; it can't be constant. */
24523 /* A constant expression is value-dependent if any subexpression is
24524 value-dependent. */
24526 {
24533 {
24537 {
24540 /* In some cases, some of the operands may be missing.
24541 (For example, in the case of PREDECREMENT_EXPR, the
24542 amount to increment by may be missing.) That doesn't
24543 make the expression dependent. */
24546 }
24547 }
24551 }
24553 }
24555 /* The expression is not value-dependent. */
24557 }
24559 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24560 [temp.dep.expr]. Note that an expression with no type is
24561 considered dependent. Other parts of the compiler arrange for an
24562 expression with type-dependent subexpressions to have no type, so
24563 this function doesn't have to be fully recursive. */
24565 bool
24567 {
24576 /* An unresolved name is always dependent. */
24582 /* A fold expression is type-dependent. */
24589 /* Some expression forms are never type-dependent. */
24603 /* The types of these expressions depends only on the type to which
24604 the cast occurs. */
24613 /* The types of these expressions depends only on the type created
24614 by the expression. */
24617 {
24618 /* For NEW_EXPR tree nodes created inside a template, either
24619 the object type itself or a TREE_LIST may appear as the
24620 operand 1. */
24623 /* This is an array type. We need to check array dimensions
24624 as well. */
24626 || value_dependent_expression_p
24628 else
24630 }
24633 {
24637 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24638 contains an identifier associated by name lookup with one or more
24639 declarations declared with a dependent type, or...a
24640 nested-name-specifier or qualified-id that names a member of an
24641 unknown specialization. */
24644 }
24654 {
24655 tree elt;
24659 {
24662 }
24664 }
24666 /* A static data member of the current instantiation with incomplete
24667 array type is type-dependent, as the definition and specializations
24668 can have different bounds. */
24675 /* An array of unknown bound depending on a variadic parameter, eg:
24677 template<typename... Args>
24678 void foo (Args... args)
24679 {
24680 int arr[] = { args... };
24681 }
24683 template<int... vals>
24684 void bar ()
24685 {
24686 int arr[] = { vals... };
24687 }
24689 If the array has no length and has an initializer, it must be that
24690 we couldn't determine its length in cp_complete_array_type because
24691 it is dependent. */
24699 /* A function or variable template-id is type-dependent if it has any
24700 dependent template arguments. */
24704 {
24705 /* Consider the innermost template arguments, since those are the ones
24706 that come from the template-id; the template arguments for the
24707 enclosing class do not make it type-dependent unless they are used in
24708 the type of the decl. */
24710 && (any_dependent_template_arguments_p
24713 }
24715 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24716 type-dependent. Checking this is important for functions with auto return
24717 type, which looks like a dependent type. */
24726 {
24730 }
24732 /* Always dependent, on the number of arguments if nothing else. */
24737 {
24742 {
24748 }
24749 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24754 {
24759 }
24762 {
24769 }
24779 }
24783 /* Dependent type attributes might not have made it from the decl to
24784 the type yet. */
24790 }
24792 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24793 type-dependent if the expression refers to a member of the current
24794 instantiation and the type of the referenced member is dependent, or the
24795 class member access expression refers to a member of an unknown
24796 specialization.
24798 This function returns true if the OBJECT in such a class member access
24799 expression is of an unknown specialization. */
24801 bool
24803 {
24804 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24805 dependent. */
24810 }
24812 /* walk_tree callback function for instantiation_dependent_expression_p,
24813 below. Returns non-zero if a dependent subexpression is found. */
24815 static tree
24818 {
24820 {
24821 /* We don't have to worry about decltype currently because decltype
24822 of an instantiation-dependent expr is a dependent type. This
24823 might change depending on the resolution of DR 1172. */
24826 }
24829 {
24830 /* Don't treat an argument list as dependent just because it has no
24831 TREE_TYPE. */
24839 /* Handle expressions with type operands. */
24844 {
24849 {
24852 else
24853 {
24856 }
24857 }
24859 }
24863 /* In a template, finish_class_member_access_expr creates a
24864 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24865 type-dependent, so that we can check access control at
24866 instantiation time (PR 42277). See also Core issue 1273. */
24873 else
24876 /* Treat statement-expressions as dependent. */
24880 /* Treat requires-expressions as dependent. */
24885 /* Treat calls to function concepts as dependent. */
24891 /* And variable concepts. */
24898 }
24902 else
24904 }
24906 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24907 sense defined by the ABI:
24909 "An expression is instantiation-dependent if it is type-dependent
24910 or value-dependent, or it has a subexpression that is type-dependent
24911 or value-dependent."
24913 Except don't actually check value-dependence for unevaluated expressions,
24914 because in sizeof(i) we don't care about the value of i. Checking
24915 type-dependence will in turn check value-dependence of array bounds/template
24916 arguments as needed. */
24918 bool
24920 {
24921 tree result;
24932 }
24934 /* As above, but also check value-dependence of the expression as a whole. */
24936 bool
24938 {
24941 }
24943 /* Like type_dependent_expression_p, but it also works while not processing
24944 a template definition, i.e. during substitution or mangling. */
24946 bool
24948 {
24954 }
24956 /* Returns TRUE if ARGS contains a type-dependent expression. */
24958 bool
24960 {
24962 tree arg;
24965 {
24968 }
24970 }
24972 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24973 expressions) contains any type-dependent expressions. */
24975 bool
24977 {
24983 }
24985 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24986 expressions) contains any value-dependent expressions. */
24988 bool
24990 {
24996 }
24998 /* Returns TRUE if the ARG (a template argument) is dependent. */
25000 bool
25002 {
25006 /* Assume a template argument that was wrongly written by the user
25007 is dependent. This is consistent with what
25008 any_dependent_template_arguments_p [that calls this function]
25009 does. */
25019 {
25022 /* A member template of a dependent class is not necessarily
25023 type-dependent, but it is a dependent template argument because it
25024 will be a member of an unknown specialization to that template. */
25027 }
25029 {
25033 {
25036 }
25039 }
25042 else
25045 }
25047 /* Returns true if ARGS (a collection of template arguments) contains
25048 any types that require structural equality testing. */
25050 bool
25052 {
25062 {
25065 {
25071 {
25072 /* Look inside the argument pack. */
25075 }
25078 {
25091 }
25092 }
25093 }
25096 }
25098 /* Returns true if ARGS (a collection of template arguments) contains
25099 any dependent arguments. */
25101 bool
25103 {
25113 {
25118 }
25121 }
25123 /* Returns true if ARGS contains any errors. */
25125 bool
25127 {
25135 {
25138 else
25140 }
25146 {
25151 }
25154 }
25156 /* Returns TRUE if the template TMPL is type-dependent. */
25158 bool
25160 {
25162 {
25167 }
25169 /* Template template parameters are dependent. */
25173 /* So are names that have not been looked up. */
25177 }
25179 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25181 bool
25183 {
25186 }
25188 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25189 are dependent. */
25191 bool
25193 {
25200 {
25222 {
25226 }
25230 {
25234 {
25239 }
25240 }
25241 }
25244 }
25246 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25247 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25248 no such TYPE can be found. Note that this function peers inside
25249 uninstantiated templates and therefore should be used only in
25250 extremely limited situations. ONLY_CURRENT_P restricts this
25251 peering to the currently open classes hierarchy (which is required
25252 when comparing types). */
25254 tree
25256 {
25257 tree scope;
25258 tree name;
25259 tree decl;
25261 tree pushed_scope;
25262 tree result;
25267 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25270 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25271 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25272 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25273 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25274 identifier of the TYPENAME_TYPE anymore.
25275 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25276 TYPENAME_TYPE instead, we avoid messing up with a possible
25277 typedef variant case. */
25280 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25281 it first before we can figure out what NAME refers to. */
25283 {
25285 /* Given a class template A with a dependent base with nested type C,
25286 typedef typename A::C::C C will land us here, as trying to resolve
25287 the initial A::C leads to the local C typedef, which leads back to
25288 A::C::C. So we break the recursion now. */
25290 else
25292 }
25293 /* If we don't know what SCOPE refers to, then we cannot resolve the
25294 TYPENAME_TYPE. */
25297 /* If this is a typedef, we don't want to look inside (c++/11987). */
25300 /* If SCOPE isn't the template itself, it will not have a valid
25301 TYPE_FIELDS list. */
25303 /* scope is either the template itself or a compatible instantiation
25304 like X<T>, so look up the name in the original template. */
25306 /* If scope has no fields, it can't be a current instantiation. Check this
25307 before currently_open_class to avoid infinite recursion (71515). */
25310 /* If the SCOPE is not the current instantiation, there's no reason
25311 to look inside it. */
25314 /* Enter the SCOPE so that name lookup will be resolved as if we
25315 were in the class definition. In particular, SCOPE will no
25316 longer be considered a dependent type. */
25318 /* Look up the declaration. */
25320 tf_warning_or_error);
25324 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25325 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25331 {
25335 }
25338 {
25339 /* Obtain the template and the arguments. */
25342 {
25343 /* We get here with a plain identifier because a previous tentative
25344 parse of the nested-name-specifier as part of a ptr-operator saw
25345 ::template X<A>. The use of ::template is necessary in a
25346 ptr-operator, but wrong in a declarator-id.
25348 [temp.names]: In a qualified-id of a declarator-id, the keyword
25349 template shall not appear at the top level. */
25353 }
25355 /* Instantiate the template. */
25361 }
25363 /* Leave the SCOPE. */
25367 /* If we failed to resolve it, return the original typename. */
25371 /* If lookup found a typename type, resolve that too. */
25373 {
25374 /* Ill-formed programs can cause infinite recursion here, so we
25375 must catch that. */
25379 }
25381 /* Qualify the resulting type. */
25387 }
25389 /* EXPR is an expression which is not type-dependent. Return a proxy
25390 for EXPR that can be used to compute the types of larger
25391 expressions containing EXPR. */
25393 tree
25395 {
25397 tree inner_expr;
25399 /* When checking, try to get a constant value for all non-dependent
25400 expressions in order to expose bugs in *_dependent_expression_p
25401 and constexpr. This can affect code generation, see PR70704, so
25402 only do this for -fchecking=2. */
25405 /* Don't do this during nsdmi parsing as it can lead to
25406 unexpected recursive instantiations. */
25408 /* Don't do this during concept expansion either and for
25409 the same reason. */
25415 /* Preserve OVERLOADs; the functions must be available to resolve
25416 types. */
25427 /* There is no need to return a proxy for a variable. */
25430 /* Preserve string constants; conversions from string constants to
25431 "char *" are allowed, even though normally a "const char *"
25432 cannot be used to initialize a "char *". */
25435 /* Preserve void and arithmetic constants, as an optimization -- there is no
25436 reason to create a new node. */
25441 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25442 There is at least one place where we want to know that a
25443 particular expression is a throw-expression: when checking a ?:
25444 expression, there are special rules if the second or third
25445 argument is a throw-expression. */
25449 /* Don't wrap an initializer list, we need to be able to look inside. */
25453 /* Don't wrap a dummy object, we need to be able to test for it. */
25472 /* If the type is unknown, it can't really be non-dependent */
25475 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25477 }
25479 /* ARGS is a vector of expressions as arguments to a function call.
25480 Replace the arguments with equivalent non-dependent expressions.
25481 This modifies ARGS in place. */
25483 void
25485 {
25487 tree arg;
25490 {
25494 }
25495 }
25497 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25498 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25499 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25501 static tree
25503 {
25517 }
25519 tree
25521 {
25523 }
25525 tree
25527 {
25529 }
25531 /* Return a C++17 deduction placeholder for class template TMPL. */
25533 tree
25535 {
25539 }
25541 /* True iff T is a C++17 class template deduction placeholder. */
25543 bool
25545 {
25547 }
25549 /* Make a "constrained auto" type-specifier. This is an
25550 auto type with constraints that must be associated after
25551 deduction. The constraint is formed from the given
25552 CONC and its optional sequence of arguments, which are
25553 non-null if written as partial-concept-id. */
25555 tree
25557 {
25560 /* Build the constraint. */
25568 /* Our canonical type depends on the constraint. */
25571 /* Attach the constraint to the type declaration. */
25574 }
25576 /* Given type ARG, return std::initializer_list<ARG>. */
25578 static tree
25580 {
25584 {
25588 "deducing from brace-enclosed initializer list"
25592 }
25598 }
25600 /* Replace auto in TYPE with std::initializer_list<auto>. */
25602 static tree
25604 {
25611 }
25613 /* Hash traits for hashing possibly constrained 'auto'
25614 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25617 {
25620 };
25622 /* Hash the 'auto' T. */
25624 inline hashval_t
25626 {
25628 /* Matching constrained-type-specifiers denote the same template
25629 parameter, so hash the constraint. */
25631 else
25632 /* But unconstrained autos are all separate, so just hash the pointer. */
25634 }
25636 /* Compare two 'auto's. */
25640 {
25647 /* Two unconstrained autos are distinct. */
25652 }
25654 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25655 constrained) auto, add it to the vector. */
25657 static int
25659 {
25662 {
25663 /* All the autos were built with index 0; fix that up now. */
25667 /* If this is a repeated constrained-type-specifier, use the index we
25668 chose before. */
25670 else
25671 {
25672 /* Otherwise this is new, so use the current count. */
25675 }
25677 }
25679 /* Always keep walking. */
25681 }
25683 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25684 says they can appear anywhere in the type. */
25686 static tree
25688 {
25697 {
25702 }
25705 }
25707 /* The stem for deduction guide names. */
25710 /* Return the name for a deduction guide for class template TMPL. */
25712 tree
25714 {
25725 }
25727 /* True if NAME is the name of a deduction guide. */
25729 bool
25731 {
25736 }
25738 /* True if FN is a deduction guide. */
25740 bool
25742 {
25747 }
25749 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25751 bool
25753 {
25760 }
25762 /* True if FN is a guide generated from a constructor template. */
25764 bool
25766 {
25774 }
25776 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25777 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25778 template parameter types. Note that the handling of template template
25779 parameters relies on current_template_parms being set appropriately for the
25780 new template. */
25782 static tree
25785 {
25788 tree newtype;
25791 {
25798 }
25799 else
25800 {
25803 {
25804 // Substitute once to fix references to other template parameters.
25807 // Now substitute again to reduce the level of the auto.
25810 }
25811 else
25814 }
25816 tree newdecl
25821 tree newidx;
25824 {
25834 {
25839 // First create a copy (ttargs) of tsubst_args with an
25840 // additional level for the template template parameter's own
25841 // template parameters (ttparms).
25842 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25850 // Substitute ttargs into ttparms to fix references to
25851 // other template parameters.
25854 // Now substitute again with args based on tparms, to reduce
25855 // the level of the ttparms.
25858 complain);
25859 // Finally, tack the adjusted parms onto tparms.
25861 current_template_parms);
25863 }
25864 }
25865 else
25866 {
25868 tree newconst
25880 }
25883 }
25885 /* Returns a C++17 class deduction guide template based on the constructor
25886 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25887 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25889 static tree
25891 {
25895 location_t loc;
25899 {
25903 {
25906 }
25907 else
25917 }
25918 else
25919 {
25922 fn_tmpl
25932 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25933 fully specialized args for the enclosing class. Strip those off, as
25934 the deduction guide won't have those template parameters. */
25937 /* Discard the 'this' parameter. */
25945 {
25948 /* For a member template constructor, we need to flatten the two
25949 template parameter lists into one, and then adjust the function
25950 signature accordingly. This gets...complicated. */
25953 /* For a member template we should have two levels of parms/args, one
25954 for the class and one for the constructor. We stripped
25955 specialized args for further enclosing classes above. */
25959 /* Template args for translating references to the two-level template
25960 parameters into references to the one-level template parameters we
25961 are creating. */
25966 /* Template parms for the constructor template. */
25969 /* Template parms for the class template. */
25973 /* Template parms for the deduction guide start as a copy of the
25974 template parms for the class. We set current_template_parms for
25975 lookup_template_class_1. */
25981 /* Now we need to rewrite the constructor parms to append them to the
25982 class parms. */
25984 {
25999 }
26001 /* Now we have a final set of template parms to substitute into the
26002 function signature. */
26011 }
26013 }
26016 {
26017 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26021 }
26025 FUNCTION_DECL,
26042 }
26044 /* Deduce template arguments for the class template placeholder PTYPE for
26045 template TMPL based on the initializer INIT, and return the resulting
26046 type. */
26048 static tree
26050 tsubst_flags_t complain)
26051 {
26053 {
26054 /* We should have handled this in the caller. */
26060 }
26071 {
26074 {
26075 /* As an exception, the first phase in 16.3.1.7 (considering the
26076 initializer list as a single argument) is omitted if the
26077 initializer list consists of a single expression of type cv U,
26078 where U is a specialization of C or a class derived from a
26079 specialization of C. */
26090 }
26093 else
26095 }
26096 else
26107 /* Prune explicit deduction guides in copy-initialization context. */
26109 {
26115 {
26116 /* Found a nonconverting guide, prune the candidates. */
26123 }
26124 }
26129 {
26132 }
26135 // FIXME cache artificial deduction guides
26137 {
26142 else
26146 }
26150 /* If this is list-initialization and the class has a list constructor, first
26151 try deducing from the list as a single argument, as [over.match.list]. */
26155 {
26159 }
26161 {
26167 {
26168 /* That didn't work, now try treating the list as a sequence of
26169 arguments. */
26172 }
26173 }
26175 /* Maybe generate an implicit deduction guide. */
26177 {
26181 /* Generate a copy guide. */
26184 /* Generate a default guide. */
26188 {
26191 }
26192 }
26195 {
26197 " of %qT, as it has no non-explicit deduction guides or "
26200 }
26202 {
26206 }
26209 {
26213 }
26216 {
26226 }
26231 }
26233 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26234 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26235 The CONTEXT determines the context in which auto deduction is performed
26236 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26237 OUTER_TARGS are used during template argument deduction
26238 (context == adc_unify) to properly substitute the result, and is ignored
26239 in other contexts.
26241 For partial-concept-ids, extra args may be appended to the list of deduced
26242 template arguments prior to determining constraint satisfaction. */
26244 tree
26248 {
26249 tree targs;
26256 /* Defining a subset of type-dependent expressions that we can deduce
26257 from ahead of time isn't worth the trouble. */
26260 /* Similarly, we can't deduce from another undeduced decl. */
26265 /* C++17 class template argument deduction. */
26269 /* Nothing we can do with this, even in deduction context. */
26272 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26273 with either a new invented type template parameter U or, if the
26274 initializer is a braced-init-list (8.5.4), with
26275 std::initializer_list<U>. */
26277 {
26282 else
26283 {
26285 {
26289 "for deduction to %<std::initializer_list%>, use copy-"
26291 }
26293 }
26294 }
26305 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26306 and initializer has array type, deduce cv-qualified array type. */
26308 complain);
26310 {
26319 {
26323 }
26324 }
26325 else
26326 {
26328 tree tparms;
26332 else
26333 {
26337 }
26344 {
26346 /* Try again at instantiation time. */
26350 /* If type is error_mark_node a diagnostic must have been
26351 emitted by now. Also, having a mention to '<type error>'
26352 in the diagnostic is not really useful to the user. */
26353 {
26357 else
26362 }
26364 }
26365 }
26367 /* Check any placeholder constraints against the deduced type. */
26370 {
26371 /* Use the deduced type to check the associated constraints. If we
26372 have a partial-concept-id, rebuild the argument list so that
26373 we check using the extra arguments. */
26377 {
26380 }
26381 else
26384 {
26386 {
26388 {
26406 }
26408 }
26410 }
26411 }
26417 }
26419 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26420 result. */
26422 tree
26424 {
26426 {
26432 /* In an abbreviated function template we didn't know we were dealing
26433 with a function template when we saw the auto return type, so update
26434 it to have the correct level. */
26436 }
26438 }
26440 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26441 'decltype(auto)' or a deduced class template. */
26443 bool
26445 {
26451 else
26453 }
26455 /* for_each_template_parm callback for type_uses_auto. */
26457 int
26459 {
26461 }
26463 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26464 a use of `auto'. Returns NULL_TREE otherwise. */
26466 tree
26468 {
26472 {
26473 /* The Concepts TS allows multiple autos in one type-specifier; just
26474 return the first one we find, do_auto_deduction will collect all of
26475 them. */
26479 else
26481 }
26482 else
26484 }
26486 /* For a given template T, return the vector of typedefs referenced
26487 in T for which access check is needed at T instantiation time.
26488 T is either a FUNCTION_DECL or a RECORD_TYPE.
26489 Those typedefs were added to T by the function
26490 append_type_to_template_for_access_check. */
26494 {
26495 tree ti;
26506 {
26511 }
26514 }
26516 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26517 tied to T. That list of typedefs will be access checked at
26518 T instantiation time.
26519 T is either a FUNCTION_DECL or a RECORD_TYPE.
26520 TYPE_DECL is a TYPE_DECL node representing a typedef.
26521 SCOPE is the scope through which TYPE_DECL is accessed.
26522 LOCATION is the location of the usage point of TYPE_DECL.
26524 This function is a subroutine of
26525 append_type_to_template_for_access_check. */
26527 static void
26529 tree type_decl,
26530 tree scope,
26531 location_t location)
26532 {
26533 qualified_typedef_usage_t typedef_usage;
26534 tree ti;
26541 && type_decl
26555 }
26557 /* Append TYPE_DECL to the template TEMPL.
26558 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26559 At TEMPL instanciation time, TYPE_DECL will be checked to see
26560 if it can be accessed through SCOPE.
26561 LOCATION is the location of the usage point of TYPE_DECL.
26563 e.g. consider the following code snippet:
26565 class C
26566 {
26567 typedef int myint;
26568 };
26570 template<class U> struct S
26571 {
26572 C::myint mi; // <-- usage point of the typedef C::myint
26573 };
26575 S<char> s;
26577 At S<char> instantiation time, we need to check the access of C::myint
26578 In other words, we need to check the access of the myint typedef through
26579 the C scope. For that purpose, this function will add the myint typedef
26580 and the scope C through which its being accessed to a list of typedefs
26581 tied to the template S. That list will be walked at template instantiation
26582 time and access check performed on each typedefs it contains.
26583 Note that this particular code snippet should yield an error because
26584 myint is private to C. */
26586 void
26588 tree type_decl,
26589 tree scope,
26590 location_t location)
26591 {
26597 /* Make sure we don't append the type to the template twice. */
26604 }
26606 /* Convert the generic type parameters in PARM that match the types given in the
26607 range [START_IDX, END_IDX) from the current_template_parms into generic type
26608 packs. */
26610 tree
26612 {
26623 {
26624 /* Create a distinct parameter pack type from the current parm and add it
26625 to the replacement args to tsubst below into the generic function
26626 parameter. */
26641 }
26647 /* If there are more levels then build up the replacement with the outer
26648 template parms. */
26652 replacement);
26655 }
26657 /* Entries in the decl_constraint hash table. */
26659 {
26660 tree decl;
26661 tree ci;
26662 };
26664 /* Hashing function and equality for constraint entries. */
26666 {
26668 {
26670 }
26673 {
26675 }
26676 };
26678 /* A mapping from declarations to constraint information. Note that
26679 both templates and their underlying declarations are mapped to the
26680 same constraint information.
26682 FIXME: This is defined in pt.c because garbage collection
26683 code is not being generated for constraint.cc. */
26687 /* Returns the template constraints of declaration T. If T is not
26688 constrained, return NULL_TREE. Note that T must be non-null. */
26690 tree
26692 {
26703 else
26705 }
26707 /* Associate the given constraint information CI with the declaration
26708 T. If T is a template, then the constraints are associated with
26709 its underlying declaration. Don't build associations if CI is
26710 NULL_TREE. */
26712 void
26714 {
26726 }
26728 /* Remove the associated constraints of the declaration T. */
26730 void
26732 {
26741 }
26743 /* Memoized satisfaction results for declarations. This
26744 maps the pair (constraint_info, arguments) to the result computed
26745 by constraints_satisfied_p. */
26748 {
26749 tree ci;
26750 tree args;
26751 tree result;
26752 };
26754 /* Hashing function and equality for constraint entries. */
26757 {
26759 {
26762 }
26765 {
26767 }
26768 };
26770 /* Memoized satisfaction results for concept checks. */
26773 {
26774 tree tmpl;
26775 tree args;
26776 tree result;
26777 };
26779 /* Hashing function and equality for constraint entries. */
26782 {
26784 {
26786 }
26789 {
26794 }
26795 };
26800 /* Search for a memoized satisfaction result. Returns one of the
26801 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26803 tree
26805 {
26810 else
26812 }
26814 /* Memoize the result of a satisfication test. Returns the saved result. */
26816 tree
26818 {
26825 }
26827 /* Search for a memoized satisfaction result for a concept. */
26829 tree
26831 {
26836 else
26838 }
26840 /* Memoize the result of a concept check. Returns the saved result. */
26842 tree
26844 {
26851 }
26855 /* Returns a prior concept specialization. This returns the substituted
26856 and normalized constraints defined by the concept. */
26858 tree
26860 {
26865 else
26867 }
26869 /* Save a concept expansion for later. */
26871 tree
26873 {
26880 }
26882 static hashval_t
26884 {
26893 }
26895 /* Compare the constraints of two subsumption entries. The LEFT1 and
26896 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26897 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26899 static bool
26901 {
26909 }
26911 /* Key/value pair for learning and memoizing subsumption results. This
26912 associates a pair of check constraints (including arguments) with
26913 a boolean value indicating the result. */
26916 {
26917 tree t1;
26918 tree t2;
26920 };
26922 /* Hashing function and equality for constraint entries. */
26925 {
26927 {
26929 }
26932 {
26937 }
26938 };
26942 /* Search for a previously cached subsumption result. */
26946 {
26951 else
26953 }
26955 /* Save a subsumption result. */
26957 bool
26959 {
26966 }
26968 /* Set up the hash table for constraint association. */
26970 void
26972 {
26981 }
26983 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26984 0..N-1. */
26986 void
26988 {
26991 integer_type_node,
26992 NULL_TREE),
26996 }
26998 /* Set up the hash tables for template instantiations. */
27000 void
27002 {
27008 }
27010 /* Print stats about the template hash tables for -fstats. */
27012 void
27014 {
27023 }
27025 #if CHECKING_P
27029 /* Verify that build_non_dependent_expr () works, for various expressions,
27030 and that location wrappers don't affect the results. */
27032 static void
27034 {
27037 /* Verify constants, without and with location wrappers. */
27054 }
27056 /* Verify that type_dependent_expression_p () works correctly, even
27057 in the presence of location wrapper nodes. */
27059 static void
27061 {
27066 /* If no templates are involved, nothing is type-dependent. */
27072 /* Within a template, an unresolved name is always type-dependent. */
27075 /* Ensure it copes with NULL_TREE and errors. */
27079 /* A USING_DECL in a template should be type-dependent, even if wrapped
27080 with a location wrapper (PR c++/83799). */
27089 }
27091 /* Run all of the selftests within this file. */
27093 void
27095 {
27098 }