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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 alias template (needed by instantiate_decl). */
232 static void
234 {
242 else
246 {
247 saved_access_scope = tree_cons
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 static void
258 {
260 {
263 }
267 else
269 }
271 /* Do any processing required when DECL (a member template
272 declaration) is finished. Returns the TEMPLATE_DECL corresponding
273 to DECL, unless it is a specialization, in which case the DECL
274 itself is returned. */
276 tree
278 {
285 {
286 tree type;
294 {
298 }
300 }
304 {
306 {
309 }
310 else
312 }
313 else
317 }
319 /* Create a template info node. */
321 tree
323 {
328 }
330 /* Return the template info node corresponding to T, whatever T is. */
332 tree
334 {
356 }
358 /* Returns the template nesting level of the indicated class TYPE.
360 For example, in:
361 template <class T>
362 struct A
363 {
364 template <class U>
365 struct B {};
366 };
368 A<T>::B<U> has depth two, while A<T> has depth one.
369 Both A<T>::B<int> and A<int>::B<U> have depth one, if
370 they are instantiations, not specializations.
372 This function is guaranteed to return 0 if passed NULL_TREE so
373 that, for example, `template_class_depth (current_class_type)' is
374 always safe. */
376 int
378 {
382 {
393 else
395 }
398 }
400 /* Subroutine of maybe_begin_member_template_processing.
401 Returns true if processing DECL needs us to push template parms. */
403 static bool
405 {
411 }
413 /* Subroutine of maybe_begin_member_template_processing.
414 Push the template parms in PARMS, starting from LEVELS steps into the
415 chain, and ending at the beginning, since template parms are listed
416 innermost first. */
418 static void
420 {
428 current_template_parms
434 NULL);
436 {
445 {
452 /* Push the CONST_DECL. */
458 }
459 }
460 }
462 /* Restore the template parameter context for a member template, a
463 friend template defined in a class definition, or a non-template
464 member of template class. */
466 void
468 {
469 tree parms;
474 {
477 /* Disregard full specializations (c++/60999). */
480 }
483 {
488 {
491 }
494 }
496 /* Remember how many levels of template parameters we pushed so that
497 we can pop them later. */
499 }
501 /* Undo the effects of maybe_begin_member_template_processing. */
503 void
505 {
514 {
518 }
519 }
521 /* Return a new template argument vector which contains all of ARGS,
522 but has as its innermost set of arguments the EXTRA_ARGS. */
524 static tree
526 {
527 tree new_args;
545 }
547 /* Like add_to_template_args, but only the outermost ARGS are added to
548 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
549 (EXTRA_ARGS) levels are added. This function is used to combine
550 the template arguments from a partial instantiation with the
551 template arguments used to attain the full instantiation from the
552 partial instantiation. */
554 static tree
556 {
557 tree new_args;
559 /* If there are more levels of EXTRA_ARGS than there are ARGS,
560 something very fishy is going on. */
563 /* If *all* the new arguments will be the EXTRA_ARGS, just return
564 them. */
568 /* For the moment, we make ARGS look like it contains fewer levels. */
573 /* Now, we restore ARGS to its full dimensions. */
577 }
579 /* Return the N levels of innermost template arguments from the ARGS. */
581 tree
583 {
584 tree new_args;
590 /* If N is 1, just return the innermost set of template arguments. */
594 /* If we're not removing anything, just return the arguments we were
595 given. */
601 /* Make a new set of arguments, not containing the outer arguments. */
608 }
610 /* The inverse of get_innermost_template_args: Return all but the innermost
611 EXTRA_LEVELS levels of template arguments from the ARGS. */
613 static tree
615 {
616 tree new_args;
622 /* If N is 1, just return the outermost set of template arguments. */
626 /* If we're not removing anything, just return the arguments we were
627 given. */
632 /* Make a new set of arguments, not containing the inner arguments. */
639 }
641 /* We've got a template header coming up; push to a new level for storing
642 the parms. */
644 void
646 {
647 /* We use a non-tag-transparent scope here, which causes pushtag to
648 put tags in this scope, rather than in the enclosing class or
649 namespace scope. This is the right thing, since we want
650 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
651 global template class, push_template_decl handles putting the
652 TEMPLATE_DECL into top-level scope. For a nested template class,
653 e.g.:
655 template <class T> struct S1 {
656 template <class T> struct S2 {};
657 };
659 pushtag contains special code to insert the TEMPLATE_DECL for S2
660 at the right scope. */
666 /* Add a dummy parameter level while we process the parameter list. */
667 current_template_parms
670 current_template_parms);
671 }
673 /* This routine is called when a specialization is declared. If it is
674 invalid to declare a specialization here, an error is reported and
675 false is returned, otherwise this routine will return true. */
677 static bool
679 {
682 /* [temp.expl.spec]
684 An explicit specialization shall be declared in the namespace of
685 which the template is a member, or, for member templates, in the
686 namespace of which the enclosing class or enclosing class
687 template is a member. An explicit specialization of a member
688 function, member class or static data member of a class template
689 shall be declared in the namespace of which the class template
690 is a member. */
692 {
695 }
697 /* [temp.expl.spec]
699 In an explicit specialization declaration for a member of a class
700 template or a member template that appears in namespace scope,
701 the member template and some of its enclosing class templates may
702 remain unspecialized, except that the declaration shall not
703 explicitly specialize a class member template if its enclosing
704 class templates are not explicitly specialized as well. */
706 {
709 }
712 }
714 /* We've just seen template <>. */
716 bool
718 {
722 }
724 /* Called at then end of processing a declaration preceded by
725 template<>. */
727 void
729 {
732 }
734 /* Any template <>'s that we have seen thus far are not referring to a
735 function specialization. */
737 void
739 {
742 }
744 /* We've just seen a template header. If SPECIALIZATION is nonzero,
745 it was of the form template <>. */
747 static void
749 {
751 template_header_count++;
752 }
754 /* We're beginning an explicit instantiation. */
756 void
758 {
761 }
764 void
766 {
769 }
771 /* An explicit specialization or partial specialization of TMPL is being
772 declared. Check that the namespace in which the specialization is
773 occurring is permissible. Returns false iff it is invalid to
774 specialize TMPL in the current namespace. */
776 static bool
778 {
781 /* [tmpl.expl.spec]
783 An explicit specialization shall be declared in a namespace enclosing the
784 specialized template. An explicit specialization whose declarator-id is
785 not qualified shall be declared in the nearest enclosing namespace of the
786 template, or, if the namespace is inline (7.3.1), any namespace from its
787 enclosing namespace set. */
790 {
793 }
796 /* Same or enclosing namespace. */
798 else
799 {
805 }
806 }
808 /* SPEC is an explicit instantiation. Check that it is valid to
809 perform this explicit instantiation in the current namespace. */
811 static void
813 {
814 tree ns;
816 /* DR 275: An explicit instantiation shall appear in an enclosing
817 namespace of its template. */
823 }
825 // Returns the type of a template specialization only if that
826 // specialization needs to be defined. Otherwise (e.g., if the type has
827 // already been defined), the function returns NULL_TREE.
828 static tree
830 {
831 // An implicit instantiation of an incomplete type implies
832 // the definition of a new class template.
833 //
834 // template<typename T>
835 // struct S;
836 //
837 // template<typename T>
838 // struct S<T*>;
839 //
840 // Here, S<T*> is an implicit instantiation of S whose type
841 // is incomplete.
845 // It can also be the case that TYPE is a completed specialization.
846 // Continuing the previous example, suppose we also declare:
847 //
848 // template<typename T>
849 // requires Integral<T>
850 // struct S<T*>;
851 //
852 // Here, S<T*> refers to the specialization S<T*> defined
853 // above. However, we need to differentiate definitions because
854 // we intend to define a new partial specialization. In this case,
855 // we rely on the fact that the constraints are different for
856 // this declaration than that above.
857 //
858 // Note that we also get here for injected class names and
859 // late-parsed template definitions. We must ensure that we
860 // do not create new type declarations for those cases.
862 {
866 // If there are no template parameters, this cannot be a new
867 // partial template specializtion?
871 // The injected-class-name is not a new partial specialization.
875 // If the constraints are not the same as those of the primary
876 // then, we can probably create a new specialization.
880 {
884 }
886 // Also, if there's a pre-existing specialization with matching
887 // constraints, then this also isn't new.
890 {
898 }
900 // Create a new type node (and corresponding type decl)
901 // for the newly declared specialization.
906 /* We only need a separate type node for storing the definition of this
907 partial specialization; uses of S<T*> are unconstrained, so all are
908 equivalent. So keep TYPE_CANONICAL the same. */
911 // Build the corresponding type decl.
917 }
920 }
922 /* The TYPE is being declared. If it is a template type, that means it
923 is a partial specialization. Do appropriate error-checking. */
925 tree
927 {
928 tree context;
933 /* A lambda that appears in specialization context is not itself a
934 specialization. */
939 {
943 }
948 {
954 else
957 }
959 {
960 /* This is for ordinary explicit specialization and partial
961 specialization of a template class such as:
963 template <> class C<int>;
965 or:
967 template <class T> class C<T*>;
969 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
972 {
979 {
984 }
985 }
991 /* Trying to define a specialization either without a template<> header
992 or in an inappropriate place. We've already given an error, so just
993 bail now so we don't actually define the specialization. */
995 }
1001 {
1002 /* This is for an explicit specialization of member class
1003 template according to [temp.expl.spec/18]:
1005 template <> template <class U> class C<int>::D;
1007 The context `C<int>' must be an implicit instantiation.
1008 Otherwise this is just a member class template declared
1009 earlier like:
1011 template <> class C<int> { template <class U> class D; };
1012 template <> template <class U> class C<int>::D;
1014 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1015 while in the second case, `C<int>::D' is a primary template
1016 and `C<T>::D' may not exist. */
1020 {
1021 tree t;
1026 {
1031 }
1033 /* Check for invalid specialization after instantiation:
1035 template <> template <> class C<int>::D<int>;
1036 template <> template <class U> class C<int>::D; */
1040 {
1044 {
1045 /* We already have a full specialization of this partial
1046 instantiation, or a full specialization has been
1047 looked up but not instantiated. Reassign it to the
1048 new member specialization template. */
1049 spec_entry elt;
1061 spec_entry **slot
1066 }
1067 else
1068 /* But if we've had an implicit instantiation, that's a
1069 problem ([temp.expl.spec]/6). */
1072 }
1074 /* Mark TYPE as a specialization. And as a result, we only
1075 have one level of template argument for the innermost
1076 class template. */
1081 }
1082 }
1084 {
1085 /* Someday C++0x may allow for enum template specialization. */
1090 else
1091 {
1094 }
1095 }
1098 }
1100 /* Returns nonzero if we can optimize the retrieval of specializations
1101 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1102 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1106 {
1109 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1110 parameter. */
1112 /* The optimized lookup depends on the fact that the
1113 template arguments for the member function template apply
1114 purely to the containing class, which is not true if the
1115 containing class is an explicit or partial
1116 specialization. */
1120 /* It is possible to have a template that is not a member
1121 template and is not a member of a template class:
1123 template <typename T>
1124 struct S { friend A::f(); };
1126 Here, the friend function is a template, but the context does
1127 not have template information. The optimized lookup relies
1128 on having ARGS be the template arguments for both the class
1129 and the function template. */
1131 }
1133 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1134 gone through coerce_template_parms by now. */
1136 static void
1138 {
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 {
8502 /* We had some pack expansion arguments that will only work if the packs
8503 are empty, but wait until instantiation time to complain.
8504 See variadic-ttp3.C. */
8514 }
8517 {
8520 }
8527 }
8529 /* Convert all template arguments to their appropriate types, and
8530 return a vector containing the innermost resulting template
8531 arguments. If any error occurs, return error_mark_node. Error and
8532 warning messages are not issued.
8534 Note that no function argument deduction is performed, and default
8535 arguments are used to fill in unspecified arguments. */
8536 tree
8538 {
8540 }
8542 /* Convert all template arguments to their appropriate type, and
8543 instantiate default arguments as needed. This returns a vector
8544 containing the innermost resulting template arguments, or
8545 error_mark_node if unsuccessful. */
8546 tree
8548 tsubst_flags_t complain)
8549 {
8551 }
8553 /* Like coerce_template_parms. If PARMS represents all template
8554 parameters levels, this function returns a vector of vectors
8555 representing all the resulting argument levels. Note that in this
8556 case, only the innermost arguments are coerced because the
8557 outermost ones are supposed to have been coerced already.
8559 Otherwise, if PARMS represents only (the innermost) vector of
8560 parameters, this function returns a vector containing just the
8561 innermost resulting arguments. */
8563 static tree
8565 tree args,
8566 tree in_decl,
8567 tsubst_flags_t complain,
8570 {
8573 tree coerced_args;
8576 {
8578 tree level;
8584 {
8585 tree l;
8589 require_all_args,
8590 use_default_args);
8591 else
8598 }
8599 }
8600 else
8603 require_all_args,
8604 use_default_args);
8606 }
8608 /* Returns 1 if template args OT and NT are equivalent. */
8610 int
8612 {
8621 /* For member templates */
8630 {
8647 }
8651 {
8654 /* Don't treat an alias template specialization with dependent
8655 arguments as equivalent to its underlying type when used as a
8656 template argument; we need them to be distinct so that we
8657 substitute into the specialization arguments at instantiation
8658 time. And aliases can't be equivalent without being ==, so
8659 we don't need to look any deeper.
8661 During partial ordering, however, we need to treat them normally so
8662 that we can order uses of the same alias with different
8663 cv-qualification (79960). */
8667 else
8669 }
8672 else
8673 {
8674 /* Try to treat a template non-type argument that has been converted
8675 to the parameter type as equivalent to one that hasn't yet. */
8688 }
8689 }
8691 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8692 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8693 NEWARG_PTR with the offending arguments if they are non-NULL. */
8695 int
8699 {
8712 {
8717 {
8723 }
8724 }
8726 }
8730 {
8732 }
8734 static void
8736 {
8746 /* We are called both from instantiate_decl, where we've already had a
8747 tinst_level pushed, and instantiate_template, where we haven't.
8748 Compensate. */
8759 else
8768 }
8771 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8772 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8773 documentation for TEMPLATE_ID_EXPR. */
8775 tree
8777 {
8778 tree type;
8786 {
8789 }
8792 {
8794 unknown_type_node,
8796 arglist);
8798 }
8805 }
8807 /* Within the scope of a template class S<T>, the name S gets bound
8808 (in build_self_reference) to a TYPE_DECL for the class, not a
8809 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8810 or one of its enclosing classes, and that type is a template,
8811 return the associated TEMPLATE_DECL. Otherwise, the original
8812 DECL is returned.
8814 Also handle the case when DECL is a TREE_LIST of ambiguous
8815 injected-class-names from different bases. */
8817 tree
8819 {
8823 /* DR 176: A lookup that finds an injected-class-name (10.2
8824 [class.member.lookup]) can result in an ambiguity in certain cases
8825 (for example, if it is found in more than one base class). If all of
8826 the injected-class-names that are found refer to specializations of
8827 the same class template, and if the name is followed by a
8828 template-argument-list, the reference refers to the class template
8829 itself and not a specialization thereof, and is not ambiguous. */
8831 {
8834 {
8840 }
8843 else
8845 }
8851 }
8853 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8854 parameters, find the desired type.
8856 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8858 IN_DECL, if non-NULL, is the template declaration we are trying to
8859 instantiate.
8861 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8862 the class we are looking up.
8864 Issue error and warning messages under control of COMPLAIN.
8866 If the template class is really a local class in a template
8867 function, then the FUNCTION_CONTEXT is the function in which it is
8868 being instantiated.
8870 ??? Note that this function is currently called *twice* for each
8871 template-id: the first time from the parser, while creating the
8872 incomplete type (finish_template_type), and the second type during the
8873 real instantiation (instantiate_template_class). This is surely something
8874 that we want to avoid. It also causes some problems with argument
8875 coercion (see convert_nontype_argument for more information on this). */
8877 static tree
8880 {
8882 tree t;
8885 spec_entry elt;
8886 hashval_t hash;
8889 {
8893 else
8894 {
8901 }
8904 }
8906 {
8909 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8910 an implicit typename for the second A. Deal with it. */
8915 {
8918 }
8919 }
8922 {
8925 }
8927 {
8931 }
8933 {
8936 }
8938 /* Issue an error message if we didn't find a template. */
8940 {
8944 }
8947 /* Make sure it's a user visible template, if it was named by
8948 the user. */
8951 {
8953 {
8957 }
8959 }
8963 /* An alias that just changes the name of a template is equivalent to the
8964 other template, so if any of the arguments are pack expansions, strip
8965 the alias to avoid problems with a pack expansion passed to a non-pack
8966 alias template parameter (DR 1430). */
8971 {
8972 tree parm;
8981 }
8982 else
8983 {
8985 tree gen_tmpl;
8986 tree type_decl;
8994 /* An error occurred while building the template TEMPL, and a
8995 diagnostic has most certainly been emitted for that
8996 already. Let's propagate that error. */
9005 {
9006 /* We've been given an incomplete set of template arguments.
9007 For example, given:
9009 template <class T> struct S1 {
9010 template <class U> struct S2 {};
9011 template <class U> struct S2<U*> {};
9012 };
9014 we will be called with an ARGLIST of `U*', but the
9015 TEMPLATE will be `template <class T> template
9016 <class U> struct S1<T>::S2'. We must fill in the missing
9017 arguments. */
9021 }
9023 /* Now we should have enough arguments. */
9026 /* From here on, we're only interested in the most general
9027 template. */
9029 /* Calculate the BOUND_ARGS. These will be the args that are
9030 actually tsubst'd into the definition to create the
9031 instantiation. */
9033 complain,
9038 /* We were unable to bind the arguments. */
9041 /* In the scope of a template class, explicit references to the
9042 template class refer to the type of the template, not any
9043 instantiation of it. For example, in:
9045 template <class T> class C { void f(C<T>); }
9047 the `C<T>' is just the same as `C'. Outside of the
9048 class, however, such a reference is an instantiation. */
9052 {
9057 }
9059 /* If we already have this specialization, return it. */
9069 /* If the the template's constraints are not satisfied,
9070 then we cannot form a valid type.
9072 Note that the check is deferred until after the hash
9073 lookup. This prevents redundant checks on previously
9074 instantiated specializations. */
9076 {
9078 {
9081 }
9083 }
9087 /* If the deduced arguments are invalid, then the binding
9088 failed. */
9092 complain))
9099 {
9104 }
9114 /* Create the type. */
9116 {
9117 /* The user referred to a specialization of an alias
9118 template represented by GEN_TMPL.
9120 [temp.alias]/2 says:
9122 When a template-id refers to the specialization of an
9123 alias template, it is equivalent to the associated
9124 type obtained by substitution of its
9125 template-arguments for the template-parameters in the
9126 type-id of the alias template. */
9129 /* Note that the call above (by indirectly calling
9130 register_specialization in tsubst_decl) registers the
9131 TYPE_DECL representing the specialization of the alias
9132 template. So next time someone substitutes ARGLIST for
9133 the template parms into the alias template (GEN_TMPL),
9134 she'll get that TYPE_DECL back. */
9138 }
9140 {
9142 {
9153 }
9154 else
9155 {
9156 /* We don't want to call start_enum for this type, since
9157 the values for the enumeration constants may involve
9158 template parameters. And, no one should be interested
9159 in the enumeration constants for such a type. */
9162 }
9166 }
9168 {
9169 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9170 instantiated here. */
9178 /* A local class. Make sure the decl gets registered properly. */
9183 /* This instantiation is another name for the primary
9184 template type. Set the TYPE_CANONICAL field
9185 appropriately. */
9188 /* Some of the template arguments require structural
9189 equality testing, so this template class requires
9190 structural equality testing. */
9192 }
9193 else
9196 /* If we called start_enum or pushtag above, this information
9197 will already be set up. */
9199 {
9206 }
9207 else
9211 {
9217 {
9220 }
9221 }
9225 {
9229 {
9230 tree attributes
9238 }
9239 }
9241 /* Let's consider the explicit specialization of a member
9242 of a class template specialization that is implicitly instantiated,
9243 e.g.:
9244 template<class T>
9245 struct S
9246 {
9247 template<class U> struct M {}; //#0
9248 };
9250 template<>
9251 template<>
9252 struct S<int>::M<char> //#1
9253 {
9254 int i;
9255 };
9256 [temp.expl.spec]/4 says this is valid.
9258 In this case, when we write:
9259 S<int>::M<char> m;
9261 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9262 the one of #0.
9264 When we encounter #1, we want to store the partial instantiation
9265 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9267 For all cases other than this "explicit specialization of member of a
9268 class template", we just want to store the most general template into
9269 the CLASSTYPE_TI_TEMPLATE of M.
9271 This case of "explicit specialization of member of a class template"
9272 only happens when:
9273 1/ the enclosing class is an instantiation of, and therefore not
9274 the same as, the context of the most general template, and
9275 2/ we aren't looking at the partial instantiation itself, i.e.
9276 the innermost arguments are not the same as the innermost parms of
9277 the most general template.
9279 So it's only when 1/ and 2/ happens that we want to use the partial
9280 instantiation of the member template in lieu of its most general
9281 template. */
9285 /* the enclosing class must be an instantiation... */
9288 {
9292 tree partial_inst_args =
9299 use_partial_inst_tmpl =
9300 /*...and we must not be looking at the partial instantiation
9301 itself. */
9303 partial_inst_args);
9304 }
9307 /* This case is easy; there are no member templates involved. */
9309 else
9310 {
9311 /* This is a full instantiation of a member template. Find
9312 the partial instantiation of which this is an instance. */
9314 /* Temporarily reduce by one the number of levels in the ARGLIST
9315 so as to avoid comparing the last set of arguments. */
9319 /* FOUND is either a proper class type, or an alias
9320 template specialization. In the later case, it's a
9321 TYPE_DECL, resulting from the substituting of arguments
9322 for parameters in the TYPE_DECL of the alias template
9323 done earlier. So be careful while getting the template
9324 of FOUND. */
9326 ? found
9330 }
9332 // Build template info for the new specialization.
9341 /* Note this use of the partial instantiation so we can check it
9342 later in maybe_process_partial_specialization. */
9349 /* Now that the type has been registered on the instantiations
9350 list, we set up the enumerators. Because the enumeration
9351 constants may involve the enumeration type itself, we make
9352 sure to register the type first, and then create the
9353 constants. That way, doing tsubst_expr for the enumeration
9354 constants won't result in recursive calls here; we'll find
9355 the instantiation and exit above. */
9359 /* If the type makes use of template parameters, the
9360 code that generates debugging information will crash. */
9363 /* Possibly limit visibility based on template args. */
9370 }
9371 }
9373 /* Wrapper for lookup_template_class_1. */
9375 tree
9378 {
9379 tree ret;
9385 }
9387 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9389 tree
9391 {
9392 /* The type of the expression is NULL_TREE since the template-id could refer
9393 to an explicit or partial specialization. */
9396 /* Except that concepts are always bool. */
9399 }
9401 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9403 tree
9405 {
9409 /* We never want to return a VAR_DECL for a variable concept, since they
9410 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9425 {
9427 {
9430 }
9432 }
9434 /* If a template-id refers to a specialization of a variable
9435 concept, then the expression is true if and only if the
9436 concept's constraints are satisfied by the given template
9437 arguments.
9439 NOTE: This is an extension of Concepts Lite TS that
9440 allows constraints to be used in expressions. */
9442 {
9445 }
9448 }
9450 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9451 TARGS template args, and instantiate it if it's not dependent. */
9453 tree
9455 tsubst_flags_t complain)
9456 {
9459 {
9462 }
9465 }
9467 \f
9468 struct pair_fn_data
9469 {
9470 tree_fn_t fn;
9471 tree_fn_t any_fn;
9473 /* True when we should also visit template parameters that occur in
9474 non-deduced contexts. */
9477 };
9479 /* Called from for_each_template_parm via walk_tree. */
9481 static tree
9483 {
9490 #define WALK_SUBTREE(NODE) \
9491 do \
9492 { \
9493 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9494 pfd->include_nondeduced_p, \
9495 pfd->any_fn); \
9496 if (result) goto out; \
9497 } \
9498 while (0)
9508 {
9512 /* Fall through. */
9518 else
9528 /* Since we're not going to walk subtrees, we have to do this
9529 explicitly here. */
9531 /* Fall through. */
9534 /* Check the return type. */
9537 /* Check the parameter types. Since default arguments are not
9538 instantiated until they are needed, the TYPE_ARG_TYPES may
9539 contain expressions that involve template parameters. But,
9540 no-one should be looking at them yet. And, once they're
9541 instantiated, they don't contain template parameters, so
9542 there's no point in looking at them then, either. */
9543 {
9544 tree parm;
9549 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9550 want walk_tree walking into them itself. */
9552 }
9555 {
9559 }
9576 /* Fall through. */
9588 /* Record template parameters such as `T' inside `TT<T>'. */
9590 /* Fall through. */
9602 /* A template template parameter is encountered. */
9606 /* Already substituted template template parameter */
9611 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9612 partial instantiation. */
9624 /* If there's no type, then this thing must be some expression
9625 involving template parameters. */
9647 }
9649 #undef WALK_SUBTREE
9651 /* We didn't find any template parameters we liked. */
9652 out:
9654 }
9656 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9657 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9658 call FN with the parameter and the DATA.
9659 If FN returns nonzero, the iteration is terminated, and
9660 for_each_template_parm returns 1. Otherwise, the iteration
9661 continues. If FN never returns a nonzero value, the value
9662 returned by for_each_template_parm is 0. If FN is NULL, it is
9663 considered to be the function which always returns 1.
9665 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9666 parameters that occur in non-deduced contexts. When false, only
9667 visits those template parameters that can be deduced. */
9669 static tree
9673 tree_fn_t any_fn)
9674 {
9676 tree result;
9678 /* Set up. */
9684 /* Walk the tree. (Conceptually, we would like to walk without
9685 duplicates, but for_each_template_parm_r recursively calls
9686 for_each_template_parm, so we would need to reorganize a fair
9687 bit to use walk_tree_without_duplicates, so we keep our own
9688 visited list.) */
9691 else
9694 for_each_template_parm_r,
9698 /* Clean up. */
9700 {
9703 }
9706 }
9708 /* Returns true if T depends on any template parameter. */
9710 int
9712 {
9742 else
9743 {
9746 }
9751 }
9753 /* Returns true iff current_function_decl is an incompletely instantiated
9754 template. Useful instead of processing_template_decl because the latter
9755 is set to 0 during instantiate_non_dependent_expr. */
9757 bool
9759 {
9768 }
9770 /* Returns true if T depends on any template parameter with level LEVEL. */
9772 bool
9774 {
9777 }
9779 /* Returns true if the signature of DECL depends on any template parameter from
9780 its enclosing class. */
9782 bool
9784 {
9794 template_parm_outer_level,
9804 }
9806 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9807 ill-formed translation unit, i.e. a variable or function that isn't
9808 usable in a constant expression. */
9812 {
9817 }
9819 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9820 neglectable and instantiated from within an erroneous instantiation. */
9822 static bool
9824 {
9835 }
9843 /* We're starting to instantiate D; record the template instantiation context
9844 for diagnostics and to restore it later. */
9846 bool
9848 {
9850 }
9852 /* We're starting to instantiate D; record the template instantiation context
9853 at LOC for diagnostics and to restore it later. */
9855 bool
9857 {
9861 {
9862 /* Tell error.c not to try to instantiate any templates. */
9865 "template instantiation depth exceeds maximum of %d"
9867 max_tinst_depth);
9869 }
9871 /* If the current instantiation caused problems, don't let it instantiate
9872 anything else. Do allow deduction substitution and decls usable in
9873 constant expressions. */
9877 /* When not -quiet, dump template instantiations other than functions, since
9878 announce_function will take care of those. */
9897 }
9899 /* We're done instantiating this template; return to the instantiation
9900 context. */
9902 void
9904 {
9905 /* Restore the filename and line number stashed away when we started
9906 this instantiation. */
9910 }
9912 /* We're instantiating a deferred template; restore the template
9913 instantiation context in which the instantiation was requested, which
9914 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9916 static tree
9918 {
9930 }
9932 /* Returns the TINST_LEVEL which gives the original instantiation
9933 context. */
9937 {
9943 }
9945 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9946 vector of template arguments, as for tsubst.
9948 Returns an appropriate tsubst'd friend declaration. */
9950 static tree
9952 {
9953 tree new_friend;
9958 /* This was a friend declared with an explicit template
9959 argument list, e.g.:
9961 friend void f<>(T);
9963 to indicate that f was a template instantiation, not a new
9964 function declaration. Now, we have to figure out what
9965 instantiation of what template. */
9966 {
9968 tree new_args;
9969 tree tmpl;
9972 /* Friend functions are looked up in the containing namespace scope.
9973 We must enter that scope, to avoid finding member functions of the
9974 current class with same name. */
9989 tsk_none);
9991 }
9995 /* The NEW_FRIEND will look like an instantiation, to the
9996 compiler, but is not an instantiation from the point of view of
9997 the language. For example, we might have had:
9999 template <class T> struct S {
10000 template <class U> friend void f(T, U);
10001 };
10003 Then, in S<int>, template <class U> void f(int, U) is not an
10004 instantiation of anything. */
10010 {
10014 }
10016 /* The mangled name for the NEW_FRIEND is incorrect. The function
10017 is not a template instantiation and should not be mangled like
10018 one. Therefore, we forget the mangling here; we'll recompute it
10019 later if we need it. */
10021 {
10024 }
10027 {
10028 tree old_decl;
10029 tree new_friend_template_info;
10030 tree new_friend_result_template_info;
10031 tree ns;
10034 /* We must save some information from NEW_FRIEND before calling
10035 duplicate decls since that function will free NEW_FRIEND if
10036 possible. */
10038 new_friend_is_defn =
10043 {
10044 /* This declaration is a `primary' template. */
10047 new_friend_result_template_info
10049 }
10050 else
10053 /* Inside pushdecl_namespace_level, we will push into the
10054 current namespace. However, the friend function should go
10055 into the namespace of the template. */
10065 {
10066 /* This new friend declaration matched an existing
10067 declaration. For example, given:
10069 template <class T> void f(T);
10070 template <class U> class C {
10071 template <class T> friend void f(T) {}
10072 };
10074 the friend declaration actually provides the definition
10075 of `f', once C has been instantiated for some type. So,
10076 old_decl will be the out-of-class template declaration,
10077 while new_friend is the in-class definition.
10079 But, if `f' was called before this point, the
10080 instantiation of `f' will have DECL_TI_ARGS corresponding
10081 to `T' but not to `U', references to which might appear
10082 in the definition of `f'. Previously, the most general
10083 template for an instantiation of `f' was the out-of-class
10084 version; now it is the in-class version. Therefore, we
10085 run through all specialization of `f', adding to their
10086 DECL_TI_ARGS appropriately. In particular, they need a
10087 new set of outer arguments, corresponding to the
10088 arguments for this class instantiation.
10090 The same situation can arise with something like this:
10092 friend void f(int);
10093 template <class T> class C {
10094 friend void f(T) {}
10095 };
10097 when `C<int>' is instantiated. Now, `f(int)' is defined
10098 in the class. */
10101 /* On the other hand, if the in-class declaration does
10102 *not* provide a definition, then we don't want to alter
10103 existing definitions. We can just leave everything
10104 alone. */
10105 ;
10106 else
10107 {
10111 /* Overwrite whatever template info was there before, if
10112 any, with the new template information pertaining to
10113 the declaration. */
10117 {
10118 /* We should have called reregister_specialization in
10119 duplicate_decls. */
10124 /* Instantiate it if the global has already been used. */
10128 }
10129 else
10130 {
10131 tree t;
10133 /* Indicate that the old function template is a partial
10134 instantiation. */
10142 /* Reassign any specializations already in the hash table
10143 to the new more general template, and add the
10144 additional template args. */
10148 {
10150 spec_entry elt;
10162 register_specialization
10165 }
10167 }
10168 }
10170 /* The information from NEW_FRIEND has been merged into OLD_DECL
10171 by duplicate_decls. */
10173 }
10174 }
10175 else
10176 {
10180 /* In the code
10181 template <class T> class C {
10182 template <class U> friend void C1<U>::f (); // case 1
10183 friend void C2<T>::f (); // case 2
10184 };
10185 we only need to make sure CONTEXT is a complete type for
10186 case 2. To distinguish between the two cases, we note that
10187 CONTEXT of case 1 remains dependent type after tsubst while
10188 this isn't true for case 2. */
10198 {
10200 /* do_friend adds the TEMPLATE_DECL for any member friend
10201 template even if it isn't a member template, i.e.
10202 template <class T> friend A<T>::f();
10203 Look through it in that case. */
10207 /* Check to see that the declaration is really present, and,
10208 possibly obtain an improved declaration. */
10213 }
10214 }
10217 }
10219 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10220 template arguments, as for tsubst.
10222 Returns an appropriate tsubst'd friend type or error_mark_node on
10223 failure. */
10225 static tree
10227 {
10228 tree tmpl;
10231 {
10234 }
10239 else
10247 {
10248 /* The friend template has already been declared. Just
10249 check to see that the declarations match, and install any new
10250 default parameters. We must tsubst the default parameters,
10251 of course. We only need the innermost template parameters
10252 because that is all that redeclare_class_template will look
10253 at. */
10256 {
10264 }
10265 }
10266 else
10267 {
10268 /* The friend template has not already been declared. In this
10269 case, the instantiation of the template class will cause the
10270 injection of this template into the namespace scope. */
10274 {
10275 /* The new TMPL is not an instantiation of anything, so we
10276 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10277 for the new type because that is supposed to be the
10278 corresponding template decl, i.e., TMPL. */
10285 /* It is hidden. */
10290 /* Inject this template into the enclosing namspace scope. */
10292 }
10293 }
10297 else
10301 }
10303 /* Returns zero if TYPE cannot be completed later due to circularity.
10304 Otherwise returns one. */
10306 static int
10308 {
10318 else
10320 }
10325 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10326 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10328 static tree
10331 {
10340 {
10347 clauses
10351 else
10353 }
10354 /* If the first attribute argument is an identifier, don't
10355 pass it through tsubst. Attributes like mode, format,
10356 cleanup and several target specific attributes expect it
10357 unmodified. */
10359 {
10360 tree chain
10365 }
10367 {
10368 /* An attribute pack expansion. */
10377 {
10381 }
10383 }
10384 else
10391 }
10393 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10394 unchanged or a new TREE_LIST chain. */
10396 static tree
10399 {
10404 {
10408 }
10412 {
10415 {
10418 {
10424 }
10425 }
10427 }
10430 }
10432 /* Apply any attributes which had to be deferred until instantiation
10433 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10434 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10436 static void
10439 {
10441 tree t;
10448 {
10452 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10453 to our attributes parameter. */
10455 }
10456 else
10457 {
10459 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10460 lookup_template_class_1, and should be preserved. */
10464 }
10468 {
10472 }
10476 {
10481 {
10484 {
10490 }
10491 else
10493 }
10496 }
10497 }
10499 /* Perform (or defer) access check for typedefs that were referenced
10500 from within the template TMPL code.
10501 This is a subroutine of instantiate_decl and instantiate_class_template.
10502 TMPL is the template to consider and TARGS is the list of arguments of
10503 that template. */
10505 static void
10507 {
10508 location_t saved_location;
10519 {
10531 /* Make access check error messages point to the location
10532 of the use of the typedef. */
10536 tf_warning_or_error);
10537 }
10539 }
10541 static tree
10543 {
10545 tree typedecl;
10546 tree pbinfo;
10547 tree base_list;
10549 tree fn_context;
10558 /* Figure out which template is being instantiated. */
10562 /* Mark the type as in the process of being defined. */
10565 /* Determine what specialization of the original template to
10566 instantiate. */
10571 {
10572 /* This TYPE is actually an instantiation of a partial
10573 specialization. We replace the innermost set of ARGS with
10574 the arguments appropriate for substitution. For example,
10575 given:
10577 template <class T> struct S {};
10578 template <class T> struct S<T*> {};
10580 and supposing that we are instantiating S<int*>, ARGS will
10581 presently be {int*} -- but we need {int}. */
10584 }
10585 else
10586 {
10589 }
10591 /* If the template we're instantiating is incomplete, then clearly
10592 there's nothing we can do. */
10594 {
10595 /* We can try again later. */
10598 }
10600 /* If we've recursively instantiated too many templates, stop. */
10604 /* We may be in the middle of deferred access check. Disable
10605 it now. */
10612 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10617 else
10618 {
10621 }
10622 /* Use #pragma pack from the template context. */
10628 /* Set the input location to the most specialized template definition.
10629 This is needed if tsubsting causes an error. */
10641 {
10644 /* Adjust visibility for template arguments. */
10646 }
10652 /* We should never instantiate a nested class before its enclosing
10653 class; we need to look up the nested class by name before we can
10654 instantiate it, and that lookup should instantiate the enclosing
10655 class. */
10661 {
10662 tree pbase_binfo;
10663 tree pushed_scope;
10666 /* We must enter the scope containing the type, as that is where
10667 the accessibility of types named in dependent bases are
10668 looked up from. */
10671 /* Substitute into each of the bases to determine the actual
10672 basetypes. */
10674 {
10675 tree base;
10681 {
10682 expanded_bases =
10689 }
10692 {
10694 /* Extract the already-expanded base class. */
10696 else
10697 /* Substitute to figure out the base class. */
10699 NULL_TREE);
10707 }
10708 }
10710 /* The list is now in reverse order; correct that. */
10715 }
10716 /* Now call xref_basetypes to set up all the base-class
10717 information. */
10725 /* Now that our base classes are set up, enter the scope of the
10726 class, so that name lookups into base classes, etc. will work
10727 correctly. This is precisely analogous to what we do in
10728 begin_class_definition when defining an ordinary non-template
10729 class, except we also need to push the enclosing classes. */
10732 /* Now members are processed in the order of declaration. */
10735 {
10739 {
10741 {
10743 /* A closure type for a lambda in an NSDMI or default argument.
10744 Ignore it; it will be regenerated when needed. */
10747 /* Build new CLASSTYPE_NESTED_UTDS. */
10749 tree newtag;
10755 /* If the member is a class template, then -- even after
10756 substitution -- there may be dependent types in the
10757 template argument list for the class. We increment
10758 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10759 that function will assume that no types are dependent
10760 when outside of a template. */
10770 {
10774 /* Unfortunately, lookup_template_class sets
10775 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10776 instantiation (i.e., for the type of a member
10777 template class nested within a template class.)
10778 This behavior is required for
10779 maybe_process_partial_specialization to work
10780 correctly, but is not accurate in this case;
10781 the TAG is not an instantiation of anything.
10782 (The corresponding TEMPLATE_DECL is an
10783 instantiation, but the TYPE is not.) */
10786 /* Now, we call pushtag to put this NEWTAG into the scope of
10787 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10788 pushtag calling push_template_decl. We don't have to do
10789 this for enums because it will already have been done in
10790 tsubst_enum. */
10794 }
10795 }
10797 {
10798 tree r;
10807 /* Instantiate members marked with attribute used. */
10813 }
10816 /* A closure type for a lambda in an NSDMI or default argument.
10818 else
10819 {
10820 /* Build new TYPE_FIELDS. */
10822 {
10823 tree condition;
10826 condition =
10836 }
10838 {
10839 tree r;
10843 /* The file and line for this declaration, to
10844 assist in error message reporting. Since we
10845 called push_tinst_level above, we don't need to
10846 restore these. */
10856 {
10857 /* A capture pack became multiple fields. */
10860 }
10863 {
10867 {
10868 /* In [temp.inst]:
10870 [t]he initialization (and any associated
10871 side-effects) of a static data member does
10872 not occur unless the static data member is
10873 itself used in a way that requires the
10874 definition of the static data member to
10875 exist.
10877 Therefore, we do not substitute into the
10878 initialized for the static data member here. */
10879 finish_static_data_member_decl
10885 /* Instantiate members marked with attribute used. */
10888 }
10890 {
10891 /* Determine whether R has a valid type and can be
10892 completed later. If R is invalid, then its type
10893 is replaced by error_mark_node. */
10899 {
10900 /* If R's type couldn't be completed and
10901 it isn't a flexible array member (whose
10902 type is incomplete by definition) give
10903 an error. */
10906 }
10911 {
10914 }
10915 }
10917 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10918 such a thing will already have been added to the field
10919 list by tsubst_enum in finish_member_declaration in the
10920 CLASSTYPE_NESTED_UTDS case above. */
10924 {
10927 }
10928 }
10929 }
10930 }
10931 }
10932 else
10933 {
10936 {
10937 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10943 {
10944 /* template <class T> friend class C; */
10947 }
10949 {
10950 /* template <class T> friend class C::D; */
10956 }
10959 {
10960 /* This could be either
10962 friend class T::C;
10964 when dependent_type_p is false or
10966 template <class U> friend class T::C;
10968 otherwise. */
10969 /* Bump processing_template_decl in case this is something like
10970 template <class T> friend struct A<T>::B. */
10977 }
10981 {
10982 /* friend class C;
10984 where C hasn't been declared yet. Let's lookup name
10985 from namespace scope directly, bypassing any name that
10986 come from dependent base class. */
10989 /* The call to xref_tag_from_type does injection for friend
10990 classes. */
10992 friend_type =
10996 }
10998 /* friend class C<T>; */
11001 /* Otherwise it's
11003 friend class C;
11005 where C is already declared or
11007 friend class C<int>;
11009 We don't have to do anything in these cases. */
11012 /* Trick make_friend_class into realizing that the friend
11013 we're adding is a template, not an ordinary class. It's
11014 important that we use make_friend_class since it will
11015 perform some error-checking and output cross-reference
11016 information. */
11024 }
11025 else
11026 {
11027 /* Build new DECL_FRIENDLIST. */
11028 tree r;
11030 /* The file and line for this declaration, to
11031 assist in error message reporting. Since we
11032 called push_tinst_level above, we don't need to
11033 restore these. */
11037 {
11040 }
11045 {
11048 }
11049 }
11050 }
11051 }
11054 {
11055 /* Restore these before substituting into the lambda capture
11056 initializers. */
11059 }
11061 /* Set the file and line number information to whatever is given for
11062 the class itself. This puts error messages involving generated
11063 implicit functions at a predictable point, and the same point
11064 that would be used for non-template classes. */
11071 /* We don't instantiate default arguments for member functions. 14.7.1:
11073 The implicit instantiation of a class template specialization causes
11074 the implicit instantiation of the declarations, but not of the
11075 definitions or default arguments, of the class member functions,
11076 member classes, static data members and member templates.... */
11078 /* Some typedefs referenced from within the template code need to be access
11079 checked at template instantiation time, i.e now. These types were
11080 added to the template at parsing time. Let's get those and perform
11081 the access checks then. */
11091 /* The vtable for a template class can be emitted in any translation
11092 unit in which the class is instantiated. When there is no key
11093 method, however, finish_struct_1 will already have added TYPE to
11094 the keyed_classes. */
11099 }
11101 /* Wrapper for instantiate_class_template_1. */
11103 tree
11105 {
11106 tree ret;
11111 }
11113 static tree
11115 {
11116 tree r;
11122 else
11123 {
11130 }
11132 }
11134 /* Given a function parameter pack TMPL_PARM and some function parameters
11135 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11136 and set *SPEC_P to point at the next point in the list. */
11138 tree
11140 {
11141 /* Collect all of the extra "packed" parameters into an
11142 argument pack. */
11143 tree parmvec;
11153 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11157 {
11162 }
11164 /* Build the argument packs. */
11169 }
11171 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11172 NONTYPE_ARGUMENT_PACK. */
11174 static tree
11176 {
11178 }
11180 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11181 pack expansion with no extra args, 2 if it has extra args, or 0
11182 if it is not a pack expansion. */
11184 static int
11186 {
11192 /* A decl pack is itself an expansion. */
11199 }
11202 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11204 static tree
11206 {
11213 }
11215 /* This is a subroutine of tsubst_pack_expansion.
11217 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11218 mechanism to store the (non complete list of) arguments of the
11219 substitution and return a non substituted pack expansion, in order
11220 to wait for when we have enough arguments to really perform the
11221 substitution. */
11223 static bool
11227 {
11228 /* If one pack has an expansion and another pack has a normal
11229 argument or if one pack has an empty argument and an another
11230 one hasn't then tsubst_pack_expansion cannot perform the
11231 substitution and need to fall back on the
11232 PACK_EXPANSION_EXTRA mechanism. */
11240 {
11243 parm_pack;
11245 {
11250 /* We can't substitute a pack expansion with extra args into
11251 our pattern. */
11255 else
11257 }
11261 }
11263 }
11265 /* [temp.variadic]/6 says that:
11267 The instantiation of a pack expansion [...]
11268 produces a list E1,E2, ..., En, where N is the number of elements
11269 in the pack expansion parameters.
11271 This subroutine of tsubst_pack_expansion produces one of these Ei.
11273 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11274 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11275 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11276 INDEX is the index 'i' of the element Ei to produce. ARGS,
11277 COMPLAIN, and IN_DECL are the same parameters as for the
11278 tsubst_pack_expansion function.
11280 The function returns the resulting Ei upon successful completion,
11281 or error_mark_node.
11283 Note that this function possibly modifies the ARGS parameter, so
11284 it's the responsibility of the caller to restore it. */
11286 static tree
11288 tree parm_packs,
11290 tree args /* This parm gets
11292 tsubst_flags_t complain,
11293 tree in_decl)
11294 {
11295 tree t;
11298 /* For each parameter pack, change the substitution of the parameter
11299 pack to the ith argument in its argument pack, then expand the
11300 pattern. */
11302 {
11307 ith_elem_is_expansion |=
11310 /* Select the Ith argument from the pack. */
11314 {
11316 {
11321 }
11322 else
11324 }
11325 else
11326 {
11331 {
11333 /* Update the corresponding argument. */
11335 }
11336 else
11337 /* Re-use the ARGUMENT_PACK_SELECT. */
11339 }
11341 }
11343 /* Substitute into the PATTERN with the (possibly altered)
11344 arguments. */
11346 /* Expanding a fixed parameter pack from
11347 coerce_template_parameter_pack. */
11352 {
11355 else
11358 }
11362 else
11365 /* If the Ith argument pack element is a pack expansion, then
11366 the Ith element resulting from the substituting is going to
11367 be a pack expansion as well. */
11372 }
11374 /* When the unexpanded parameter pack in a fold expression expands to an empty
11375 sequence, the value of the expression is as follows; the program is
11376 ill-formed if the operator is not listed in this table.
11378 && true
11379 || false
11380 , void() */
11382 tree
11384 {
11388 {
11397 }
11403 }
11405 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11406 form an expression that combines the two terms using the
11407 operator of T. */
11409 static tree
11411 {
11415 // Handle compound assignment operators.
11420 {
11430 complain);
11431 }
11432 }
11434 /* Substitute ARGS into the pack of a fold expression T. */
11438 {
11440 }
11442 /* Substitute ARGS into the pack of a fold expression T. */
11446 {
11448 }
11450 /* Expand a PACK of arguments into a grouped as left fold.
11451 Given a pack containing elements A0, A1, ..., An and an
11452 operator @, this builds the expression:
11454 ((A0 @ A1) @ A2) ... @ An
11456 Note that PACK must not be empty.
11458 The operator is defined by the original fold expression T. */
11460 static tree
11462 {
11465 {
11468 }
11470 }
11472 /* Substitute into a unary left fold expression. */
11474 static tree
11476 tree in_decl)
11477 {
11482 {
11486 }
11489 else
11491 }
11493 /* Substitute into a binary left fold expression.
11495 Do ths by building a single (non-empty) vector of argumnts and
11496 building the expression from those elements. */
11498 static tree
11500 tree in_decl)
11501 {
11510 {
11515 }
11523 }
11525 /* Expand a PACK of arguments into a grouped as right fold.
11526 Given a pack containing elementns A0, A1, ..., and an
11527 operator @, this builds the expression:
11529 A0@ ... (An-2 @ (An-1 @ An))
11531 Note that PACK must not be empty.
11533 The operator is defined by the original fold expression T. */
11535 tree
11537 {
11538 // Build the expression.
11542 {
11545 }
11547 }
11549 /* Substitute into a unary right fold expression. */
11551 static tree
11553 tree in_decl)
11554 {
11559 {
11563 }
11566 else
11568 }
11570 /* Substitute into a binary right fold expression.
11572 Do ths by building a single (non-empty) vector of arguments and
11573 building the expression from those elements. */
11575 static tree
11577 tree in_decl)
11578 {
11587 {
11592 }
11601 }
11603 /* Walk through the pattern of a pack expansion, adding everything in
11604 local_specializations to a list. */
11606 struct el_data
11607 {
11609 tree extra;
11610 tsubst_flags_t complain;
11614 };
11615 static tree
11617 {
11623 /* Remember local typedefs (85214). */
11629 {
11631 /* Don't mess with variables declared within the pattern. */
11634 {
11635 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11638 {
11644 }
11646 {
11647 /* Handle lambda capture here, since we aren't doing any
11648 substitution now, and so tsubst_copy won't call
11649 process_outer_var_ref. */
11653 {
11659 {
11660 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11661 proxies. */
11663 {
11668 }
11670 }
11671 }
11672 }
11673 }
11677 }
11679 }
11680 static tree
11682 {
11686 }
11688 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11689 for use in PACK_EXPANSION_EXTRA_ARGS. */
11691 tree
11693 {
11699 }
11701 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11702 normal template args to ARGS. */
11704 tree
11706 {
11708 {
11710 {
11711 /* The partial instantiation involved local declarations collected in
11712 extract_local_specs; map from the general template to our local
11713 context. */
11719 /* else inst is already a full instantiation of the pack. */
11721 }
11724 }
11726 }
11728 /* Substitute ARGS into T, which is an pack expansion
11729 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11730 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11731 (if only a partial substitution could be performed) or
11732 ERROR_MARK_NODE if there was an error. */
11733 tree
11735 tree in_decl)
11736 {
11737 tree pattern;
11742 tree result;
11750 /* Add in any args remembered from an earlier partial instantiation. */
11755 /* Determine the argument packs that will instantiate the parameter
11756 packs used in the expansion expression. While we're at it,
11757 compute the number of arguments to be expanded and make sure it
11758 is consistent. */
11761 {
11768 {
11774 complain);
11775 else
11779 }
11781 {
11782 /* ??? Support use in other patterns. */
11786 }
11788 {
11789 /* We know we have correct local_specializations if this
11790 expansion is at function scope, or if we're dealing with a
11791 local parameter in a requires expression; for the latter,
11792 tsubst_requires_expr set it up appropriately. */
11795 else
11796 /* We can't rely on local_specializations for a parameter
11797 name used later in a function declaration (such as in a
11798 late-specified return type). Even if it exists, it might
11799 have the wrong value for a recursive call. */
11803 {
11804 /* This parameter pack was used in an unevaluated context. Just
11805 make a dummy decl, since it's only used for its type. */
11810 /* Partial instantiation of the parm_pack, we can't build
11811 up an argument pack yet. */
11813 else
11815 }
11817 /* This argument pack isn't fully instantiated yet. We set this
11818 flag rather than clear arg_pack because we do want to do the
11819 optimization below, and we don't want to substitute directly
11820 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11821 where it isn't expected). */
11823 }
11825 {
11829 }
11830 else
11831 {
11837 }
11844 /* This can only happen if we forget to expand an argument
11845 pack somewhere else. Just return an error, silently. */
11846 {
11850 }
11853 {
11857 /* Don't bother trying to do a partial substitution with
11858 incomplete packs; we'll try again after deduction. */
11866 {
11871 pattern);
11872 else
11874 pattern);
11876 }
11878 /* Keep track of the parameter packs and their corresponding
11879 argument packs. */
11882 }
11883 else
11884 {
11885 /* We can't substitute for this parameter pack. We use a flag as
11886 well as the missing_level counter because function parameter
11887 packs don't have a level. */
11890 }
11891 }
11893 /* If the expansion is just T..., return the matching argument pack, unless
11894 we need to call convert_from_reference on all the elements. This is an
11895 important optimization; see c++/68422. */
11898 {
11901 /* If the argument pack is a single pack expansion, pull it out. */
11906 /* Types need no adjustment, nor does sizeof..., and if we still have
11907 some pack expansion args we won't do anything yet. */
11912 /* Also optimize expression pack expansions if we can tell that the
11913 elements won't have reference type. */
11919 /* Otherwise use the normal path so we get convert_from_reference. */
11920 }
11922 /* We cannot expand this expansion expression, because we don't have
11923 all of the argument packs we need. */
11925 {
11926 /* We got some full packs, but we can't substitute them in until we
11927 have values for all the packs. So remember these until then. */
11933 }
11935 {
11936 /* There were no real arguments, we're just replacing a parameter
11937 pack with another version of itself. Substitute into the
11938 pattern and return a PACK_EXPANSION_*. The caller will need to
11939 deal with that. */
11943 else
11947 }
11952 {
11953 /* We're in a late-specified return type, so create our own local
11954 specializations map; the current map is either NULL or (in the
11955 case of recursive unification) might have bindings that we don't
11956 want to use or alter. */
11959 }
11961 /* For each argument in each argument pack, substitute into the
11962 pattern. */
11966 {
11968 i,
11970 in_decl);
11973 {
11976 }
11977 }
11979 /* Update ARGS to restore the substitution from parameter packs to
11980 their argument packs. */
11982 {
11989 else
11990 {
11998 /* Update the corresponding argument. */
12002 else
12004 }
12005 }
12008 {
12011 }
12013 /* If the dependent pack arguments were such that we end up with only a
12014 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12020 }
12022 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12023 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12024 parameter packs; all parms generated from a function parameter pack will
12025 have the same DECL_PARM_INDEX. */
12027 tree
12029 {
12031 tree patparm;
12034 {
12040 }
12041 else
12042 {
12047 }
12050 }
12052 /* Make an argument pack out of the TREE_VEC VEC. */
12054 static tree
12056 {
12057 tree pack;
12061 else
12062 {
12065 }
12068 }
12070 /* Return an exact copy of template args T that can be modified
12071 independently. */
12073 static tree
12075 {
12083 {
12088 }
12094 }
12096 /* Substitute ARGS into the vector or list of template arguments T. */
12098 static tree
12100 {
12112 {
12114 tree new_arg;
12119 {
12120 /* Substitute into an expansion expression. */
12124 /* Add to the expanded length adjustment the number of
12125 expanded arguments. We subtract one from this
12126 measurement, because the argument pack expression
12127 itself is already counted as 1 in
12128 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12129 the argument pack is empty. */
12131 }
12133 {
12134 /* Substitute into each of the arguments. */
12143 else
12148 }
12149 else
12158 }
12163 /* Make space for the expanded arguments coming from template
12164 argument packs. */
12166 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12167 arguments for a member template.
12168 In that case each TREE_VEC in ORIG_T represents a level of template
12169 arguments, and ORIG_T won't carry any non defaulted argument count.
12170 It will rather be the nested TREE_VECs that will carry one.
12171 In other words, ORIG_T carries a non defaulted argument count only
12172 if it doesn't contain any nested TREE_VEC. */
12174 {
12178 }
12180 {
12184 {
12187 /* Now expand the template argument pack "in place". */
12190 }
12191 else
12192 {
12194 out++;
12195 }
12196 }
12199 }
12201 /* Substitute ARGS into one level PARMS of template parameters. */
12203 static tree
12205 {
12212 {
12220 }
12223 }
12225 /* Return the result of substituting ARGS into the template parameters
12226 given by PARMS. If there are m levels of ARGS and m + n levels of
12227 PARMS, then the result will contain n levels of PARMS. For
12228 example, if PARMS is `template <class T> template <class U>
12229 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12230 result will be `template <int*, double, class V>'. */
12232 static tree
12234 {
12238 /* When substituting into a template, we must set
12239 PROCESSING_TEMPLATE_DECL as the template parameters may be
12240 dependent if they are based on one-another, and the dependency
12241 predicates are short-circuit outside of templates. */
12248 {
12255 }
12260 }
12262 /* Return the result of substituting ARGS into one template parameter
12263 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12264 parameter and which TREE_PURPOSE is the default argument of the
12265 template parameter. */
12267 static tree
12269 {
12290 }
12292 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12293 type T. If T is not an aggregate or enumeration type, it is
12294 handled as if by tsubst. IN_DECL is as for tsubst. If
12295 ENTERING_SCOPE is nonzero, T is the context for a template which
12296 we are presently tsubst'ing. Return the substituted value. */
12298 static tree
12300 tree args,
12301 tsubst_flags_t complain,
12302 tree in_decl,
12304 {
12309 {
12314 /* Fall through. */
12318 {
12319 tree argvec;
12320 tree context;
12321 tree r;
12325 /* In "sizeof(X<I>)" we need to evaluate "I". */
12331 /* First, determine the context for the type we are looking
12332 up. */
12335 {
12338 /* If context is a nested class inside a class template,
12339 it may still need to be instantiated (c++/33959). */
12341 }
12343 /* Then, figure out what arguments are appropriate for the
12344 type we are trying to find. For example, given:
12346 template <class T> struct S;
12347 template <class T, class U> void f(T, U) { S<U> su; }
12349 and supposing that we are instantiating f<int, double>,
12350 then our ARGS will be {int, double}, but, when looking up
12351 S we only want {double}. */
12356 else
12357 {
12361 }
12367 }
12368 else
12369 /* This is not a template type, so there's nothing to do. */
12374 }
12375 }
12379 /* Substitute into the default argument ARG (a default argument for
12380 FN), which has the indicated TYPE. */
12382 tree
12384 tsubst_flags_t complain)
12385 {
12390 /* This can happen in invalid code. */
12408 /* This default argument came from a template. Instantiate the
12409 default argument here, not in tsubst. In the case of
12410 something like:
12412 template <class T>
12413 struct S {
12414 static T t();
12415 void f(T = t());
12416 };
12418 we must be careful to do name lookup in the scope of S<T>,
12419 rather than in the current class. */
12421 /* The "this" pointer is not valid in a default argument. */
12423 {
12428 }
12433 /* The default argument expression may cause implicitly defined
12434 member functions to be synthesized, which will result in garbage
12435 collection. We must treat this situation as if we were within
12436 the body of function so as to avoid collecting live data on the
12437 stack. */
12447 /* Restore the "this" pointer. */
12449 {
12452 }
12459 /* Make sure the default argument is reasonable. */
12465 {
12469 }
12472 }
12474 /* Substitute into all the default arguments for FN. */
12476 static void
12478 {
12479 tree arg;
12480 tree tmpl_args;
12484 /* If this function is not yet instantiated, we certainly don't need
12485 its default arguments. */
12488 /* Don't do this again for clones. */
12494 arg;
12500 complain);
12501 }
12503 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12505 static tree
12507 tree lambda_fntype)
12508 {
12513 /* Nobody should be tsubst'ing into non-template functions. */
12517 {
12518 /* If T is not dependent, just return it. */
12522 /* Calculate the most general template of which R is a
12523 specialization. */
12526 /* We're substituting a lambda function under tsubst_lambda_expr but not
12527 directly from it; find the matching function we're already inside.
12528 But don't do this if T is a generic lambda with a single level of
12529 template parms, as in that case we're doing a normal instantiation. */
12535 /* Calculate the complete set of arguments used to
12536 specialize R. */
12538 (DECL_TEMPLATE_RESULT
12544 /* Check to see if we already have this specialization. */
12546 {
12550 }
12552 /* We can see more levels of arguments than parameters if
12553 there was a specialization of a member template, like
12554 this:
12556 template <class T> struct S { template <class U> void f(); }
12557 template <> template <class U> void S<int>::f(U);
12559 Here, we'll be substituting into the specialization,
12560 because that's where we can find the code we actually
12561 want to generate, but we'll have enough arguments for
12562 the most general template.
12564 We also deal with the peculiar case:
12566 template <class T> struct S {
12567 template <class U> friend void f();
12568 };
12569 template <class U> void f() {}
12570 template S<int>;
12571 template void f<double>();
12573 Here, the ARGS for the instantiation of will be {int,
12574 double}. But, we only need as many ARGS as there are
12575 levels of template parameters in CODE_PATTERN. We are
12576 careful not to get fooled into reducing the ARGS in
12577 situations like:
12579 template <class T> struct S { template <class U> void f(U); }
12580 template <class T> template <> void S<T>::f(int) {}
12582 which we can spot because the pattern will be a
12583 specialization in this case. */
12590 }
12591 else
12592 {
12593 /* This special case arises when we have something like this:
12595 template <class T> struct S {
12596 friend void f<int>(int, double);
12597 };
12599 Here, the DECL_TI_TEMPLATE for the friend declaration
12600 will be an IDENTIFIER_NODE. We are being called from
12601 tsubst_friend_function, and we want only to create a
12602 new decl (R) with appropriate types so that we can call
12603 determine_specialization. */
12606 }
12623 /* If we hit excessive deduction depth, the type is bogus even if
12624 it isn't error_mark_node, so don't build a decl. */
12628 /* We do NOT check for matching decls pushed separately at this
12629 point, as they may not represent instantiations of this
12630 template, and in any case are considered separate under the
12631 discrete model. */
12635 /* Clear out the mangled name and RTL for the instantiation. */
12638 /* Leave DECL_INITIAL set on deleted instantiations. */
12643 /* OpenMP UDRs have the only argument a reference to the declared
12644 type. We want to diagnose if the declared type is a reference,
12645 which is invalid, but as references to references are usually
12646 quietly merged, diagnose it here. */
12648 {
12649 tree argtype
12654 "reference type %qT in "
12658 argtype);
12659 }
12662 /* Type-conversion operator. Reconstruct the name, in
12663 case it's the name of one of the template's parameters. */
12673 {
12677 }
12684 /* If this is an instantiation of a function with internal
12685 linkage, we already know what object file linkage will be
12686 assigned to the instantiation. */
12695 /* We'll re-clone as appropriate in instantiate_template. */
12698 /* If we aren't complaining now, return on error before we register
12699 the specialization so that we'll complain eventually. */
12705 /* When instantiating a constrained member, substitute
12706 into the constraints to create a new constraint. */
12709 {
12712 }
12714 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12715 this in the special friend case mentioned above where
12716 GEN_TMPL is NULL. */
12718 {
12723 tree new_r
12726 /* We instantiated this while substituting into
12727 the type earlier (template/friend54.C). */
12730 /* We're not supposed to instantiate default arguments
12731 until they are called, for a template. But, for a
12732 declaration like:
12734 template <class T> void f ()
12735 { extern void g(int i = T()); }
12737 we should do the substitution when the template is
12738 instantiated. We handle the member function case in
12739 instantiate_class_template since the default arguments
12740 might refer to other members of the class. */
12745 }
12746 else
12749 /* Copy the list of befriending classes. */
12753 {
12757 }
12760 {
12764 /* If this is an instantiation of a member template, clone it.
12765 If it isn't, that'll be handled by
12766 clone_constructors_and_destructors. */
12769 }
12780 /* Possibly limit visibility based on template args. */
12783 {
12787 }
12796 }
12798 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12800 static tree
12802 tree lambda_fntype)
12803 {
12804 /* We can get here when processing a member function template,
12805 member class template, or template template parameter. */
12808 tree spec;
12809 tree tmpl_args;
12810 tree full_args;
12811 tree r;
12815 {
12816 /* Template template parameter is treated here. */
12820 /* If we get a real template back, return it. This can happen in
12821 the context of most_specialized_partial_spec. */
12824 else
12825 /* The new TEMPLATE_DECL was built in
12826 reduce_template_parm_level. */
12829 }
12832 {
12833 /* We might already have an instance of this template.
12834 The ARGS are for the surrounding class type, so the
12835 full args contain the tsubst'd args for the context,
12836 plus the innermost args from the template decl. */
12840 /* Because this is a template, the arguments will still be
12841 dependent, even after substitution. If
12842 PROCESSING_TEMPLATE_DECL is not set, the dependency
12843 predicates will short-circuit. */
12851 /* If this is a default template template argument,
12852 tsubst might not have changed anything. */
12860 }
12862 /* Make a new template decl. It will be similar to the
12863 original, but will record the current template arguments.
12864 We also create a new function declaration, which is just
12865 like the old one, but points to this new template, rather
12866 than the old one. */
12871 // Build new template info linking to the original template decl.
12873 {
12876 }
12877 else
12880 /* The template parameters for this new template are all the
12881 template parameters for the old template, except the
12882 outermost level of parameters. */
12885 complain);
12889 {
12890 tree new_type;
12898 /* For a partial specialization, we need to keep pointing to
12899 the primary template. */
12905 }
12906 else
12907 {
12908 tree new_decl;
12912 else
12922 {
12925 }
12926 else
12927 {
12930 }
12931 }
12941 /* Record this non-type partial instantiation. */
12947 }
12949 /* True if FN is the op() for a lambda in an uninstantiated template. */
12951 bool
12953 {
12958 }
12960 /* We're instantiating a variable from template function TCTX. Return the
12961 corresponding current enclosing scope. This gets complicated because lambda
12962 functions in templates are regenerated rather than instantiated, but generic
12963 lambda functions are subsequently instantiated. */
12965 static tree
12967 {
12976 {
12989 }
12991 }
12993 /* Substitute the ARGS into the T, which is a _DECL. Return the
12994 result of the substitution. Issue error and warning messages under
12995 control of COMPLAIN. */
12997 static tree
12999 {
13000 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13001 location_t saved_loc;
13006 /* Set the filename and linenumber to improve error-reporting. */
13011 {
13021 {
13029 {
13030 /* If there is a local specialization that isn't a
13031 parameter pack, it means that we're doing a "simple"
13032 substitution from inside tsubst_pack_expansion. Just
13033 return the local specialization (which will be a single
13034 parm). */
13041 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13042 the parameters in this function parameter pack. */
13046 {
13049 /* Zero-length parameter packs are boring. Just substitute
13050 into the chain. */
13054 }
13055 else
13056 {
13057 /* All we did was update the type. Make a note of that. */
13060 }
13061 }
13063 /* Loop through all of the parameters we'll build. When T is
13064 a function parameter pack, LEN is the number of expanded
13065 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13068 {
13075 /* We're on the Ith parameter of the function parameter
13076 pack. */
13077 {
13078 /* Get the Ith type. */
13081 /* Rename the parameter to include the index. */
13084 }
13086 /* We're dealing with a normal parameter. */
13094 {
13097 else
13100 }
13110 /* Keep track of the first new parameter we
13111 generate. That's what will be returned to the
13112 caller. */
13116 /* Build a proper chain of parameters when substituting
13117 into a function parameter pack. */
13120 }
13122 /* If cp_unevaluated_operand is set, we're just looking for a
13123 single dummy parameter, so don't keep going. */
13128 /* FIRST_R contains the start of the chain we've built. */
13130 }
13134 {
13141 {
13142 /* This field is a lambda capture pack. Return a TREE_VEC of
13143 the expanded fields to instantiate_class_template_1. */
13147 {
13150 }
13151 else
13152 {
13153 /* All we did was update the type. Make a note of that. */
13156 }
13157 }
13160 {
13163 {
13167 }
13177 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13178 number of bits. */
13184 {
13185 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13186 NSDMI in perform_member_init. Still set DECL_INITIAL
13187 so that we know there is one. */
13192 }
13193 /* We don't have to set DECL_CONTEXT here; it is set by
13194 finish_member_declaration. */
13202 }
13206 }
13210 /* We reach here only for member using decls. We also need to check
13211 uses_template_parms because DECL_DEPENDENT_P is not set for a
13212 using-declaration that designates a member of the current
13213 instantiation (c++/53549). */
13216 {
13220 {
13225 {
13229 {
13232 }
13233 else
13234 {
13237 }
13239 }
13240 }
13241 else
13242 {
13248 else
13249 {
13252 }
13253 }
13254 }
13255 else
13256 {
13259 }
13264 {
13267 tree spec;
13269 tree ctx;
13278 {
13279 /* If this is the canonical decl, we don't have to
13280 mess with instantiations, and often we can't (for
13281 typename, template type parms and such). Note that
13282 TYPE_NAME is not correct for the above test if
13283 we've copied the type for a typedef. */
13289 }
13291 /* Check to see if we already have the specialization we
13292 need. */
13295 {
13296 /* T is a static data member or namespace-scope entity.
13297 We have to substitute into namespace-scope variables
13298 (not just variable templates) because of cases like:
13300 template <class T> void f() { extern T t; }
13302 where the entity referenced is not known until
13303 instantiation time. */
13307 {
13309 complain,
13311 /* If CTX is unchanged, then T is in fact the
13312 specialization we want. That situation occurs when
13313 referencing a static data member within in its own
13314 class. We can use pointer equality, rather than
13315 same_type_p, because DECL_CONTEXT is always
13316 canonical... */
13318 /* ... unless T is a member template; in which
13319 case our caller can be willing to create a
13320 specialization of that template represented
13321 by T. */
13325 }
13328 {
13333 argvec = (coerce_innermost_template_parms
13341 }
13342 }
13343 else
13344 {
13345 /* A local variable. */
13347 /* Subsequent calls to pushdecl will fill this in. */
13349 /* Unless this is a reference to a static variable from an
13350 enclosing function, in which case we need to fill it in now. */
13352 {
13356 }
13358 }
13359 /* If we already have the specialization we need, there is
13360 nothing more to do. */
13362 {
13365 }
13367 /* Create a new node for the specialization we need. */
13370 {
13373 else
13381 {
13382 /* Mask off any template args past the variable's context so we
13383 don't replace the auto with an unrelated argument. */
13387 /* This should never happen with the new lambda instantiation
13388 model, but keep the handling just in case. */
13391 }
13393 }
13395 {
13396 /* Even if the original location is out of scope, the
13397 newly substituted one is not. */
13404 {
13405 /* It may seem that this case cannot occur, since:
13407 typedef void f();
13408 void g() { f x; }
13410 declares a function, not a variable. However:
13412 typedef void f();
13413 template <typename T> void g() { T t; }
13414 template void g<f>();
13416 is an attempt to declare a variable with function
13417 type. */
13419 /* R is not yet sufficiently initialized, so we
13420 just use its name. */
13423 }
13425 /* Wait until cp_finish_decl to set this again, to handle
13426 circular dependency (template/instantiate6.C). */
13431 {
13436 {
13439 }
13441 }
13445 }
13451 /* Clear out the mangled name and RTL for the instantiation. */
13455 /* The initializer must not be expanded until it is required;
13456 see [temp.inst]. */
13460 {
13466 /* Possibly limit visibility based on template args. */
13469 {
13473 }
13475 }
13478 {
13479 /* A static data member declaration is always marked
13480 external when it is declared in-class, even if an
13481 initializer is present. We mimic the non-template
13482 processing here. */
13490 }
13491 else
13492 {
13497 }
13505 /* Preserve a typedef that names a type. */
13507 {
13511 /* An alias template specialization can be dependent
13512 even if its underlying type is not. */
13514 }
13517 }
13522 }
13523 #undef RETURN
13525 out:
13526 /* Restore the file and line information. */
13530 }
13532 /* Substitute into the ARG_TYPES of a function type.
13533 If END is a TREE_CHAIN, leave it and any following types
13534 un-substituted. */
13536 static tree
13538 tree args,
13539 tree end,
13540 tsubst_flags_t complain,
13541 tree in_decl)
13542 {
13543 tree remaining_arg_types;
13547 tree default_arg;
13558 {
13559 /* For a pack expansion, perform substitution on the
13560 entire expression. Later on, we'll handle the arguments
13561 one-by-one. */
13566 /* So that we'll spin through the parameters, one by one. */
13568 else
13569 {
13570 /* We only partially substituted into the parameter
13571 pack. Our type is TYPE_PACK_EXPANSION. */
13574 }
13575 }
13588 {
13590 {
13594 }
13596 }
13597 /* DR 657. */
13601 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13602 top-level qualifiers as required. */
13605 /* We do not substitute into default arguments here. The standard
13606 mandates that they be instantiated only when needed, which is
13607 done in build_over_call. */
13610 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13611 since the new op() won't have any associated template arguments for us
13612 to refer to later. */
13618 {
13619 /* We've instantiated a template before its default arguments
13620 have been parsed. This can happen for a nested template
13621 class, and is not an error unless we require the default
13622 argument in a call of this function. */
13623 remaining_arg_types =
13626 }
13627 else
13628 remaining_arg_types =
13630 }
13633 }
13635 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13636 *not* handle the exception-specification for FNTYPE, because the
13637 initial substitution of explicitly provided template parameters
13638 during argument deduction forbids substitution into the
13639 exception-specification:
13641 [temp.deduct]
13643 All references in the function type of the function template to the
13644 corresponding template parameters are replaced by the specified tem-
13645 plate argument values. If a substitution in a template parameter or
13646 in the function type of the function template results in an invalid
13647 type, type deduction fails. [Note: The equivalent substitution in
13648 exception specifications is done only when the function is instanti-
13649 ated, at which point a program is ill-formed if the substitution
13650 results in an invalid type.] */
13652 static tree
13654 tree args,
13655 tsubst_flags_t complain,
13656 tree in_decl)
13657 {
13658 tree return_type;
13660 tree fntype;
13662 /* The TYPE_CONTEXT is not used for function/method types. */
13665 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13666 failure. */
13670 {
13671 /* Substitute the argument types. */
13683 {
13684 /* DR 1207: 'this' is in scope in the trailing return type. */
13686 }
13688 /* Substitute the return type. */
13692 {
13695 }
13696 }
13697 else
13698 /* Substitute the return type. */
13703 /* DR 486 clarifies that creation of a function type with an
13704 invalid return type is a deduction failure. */
13707 {
13709 {
13712 else
13714 }
13716 }
13717 /* And DR 657. */
13722 {
13723 /* Substitute the argument types. */
13728 }
13730 /* Construct a new type node and return it. */
13732 {
13737 }
13738 else
13739 {
13741 /* Don't pick up extra function qualifiers from the basetype. */
13744 {
13745 /* [temp.deduct]
13747 Type deduction may fail for any of the following
13748 reasons:
13750 -- Attempting to create "pointer to member of T" when T
13751 is not a class type. */
13754 r);
13756 }
13761 }
13768 }
13770 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13771 ARGS into that specification, and return the substituted
13772 specification. If there is no specification, return NULL_TREE. */
13774 static tree
13776 tree args,
13777 tsubst_flags_t complain,
13778 tree in_decl,
13780 {
13781 tree specs;
13782 tree new_specs;
13787 {
13788 /* A noexcept-specifier. */
13793 {
13794 /* Defer instantiation of noexcept-specifiers to avoid
13795 excessive instantiations (c++/49107). */
13798 {
13799 /* We already partially instantiated this member template,
13800 so combine the new args with the old. */
13805 }
13806 else
13807 {
13810 }
13811 }
13812 else
13813 new_specs = tsubst_copy_and_build
13817 }
13819 {
13822 else
13824 {
13825 tree spec;
13830 {
13831 /* Expand the pack expansion type. */
13834 in_decl);
13840 else
13841 {
13842 /* We're substituting into a member template, so
13843 we got a TYPE_PACK_EXPANSION back. Add that
13844 expansion and move on. */
13848 expanded_specs,
13849 complain);
13852 }
13853 }
13856 {
13859 else
13864 complain);
13865 }
13868 }
13869 }
13871 }
13873 /* Take the tree structure T and replace template parameters used
13874 therein with the argument vector ARGS. IN_DECL is an associated
13875 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13876 Issue error and warning messages under control of COMPLAIN. Note
13877 that we must be relatively non-tolerant of extensions here, in
13878 order to preserve conformance; if we allow substitutions that
13879 should not be allowed, we may allow argument deductions that should
13880 not succeed, and therefore report ambiguous overload situations
13881 where there are none. In theory, we could allow the substitution,
13882 but indicate that it should have failed, and allow our caller to
13883 make sure that the right thing happens, but we don't try to do this
13884 yet.
13886 This function is used for dealing with types, decls and the like;
13887 for expressions, use tsubst_expr or tsubst_copy. */
13889 tree
13891 {
13914 else
13919 /* Reuse typedefs. We need to do this to handle dependent attributes,
13920 such as attribute aligned. */
13923 {
13927 {
13928 /* DECL represents an alias template and we want to
13929 instantiate it. */
13933 }
13937 {
13941 }
13946 else
13947 /* The typedef is from a non-template context. */
13951 {
13953 r = cp_build_qualified_type_real
13957 }
13958 else
13959 {
13960 /* We don't have an instantiation yet, so drop the typedef. */
13965 }
13966 }
13983 {
14009 {
14015 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14016 needed. */
14022 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14023 with TREE_SIDE_EFFECTS that indicates this is not an integral
14024 constant expression. */
14027 {
14030 }
14033 }
14039 {
14045 /* Early in template argument deduction substitution, we don't
14046 want to reduce the level of 'auto', or it will be confused
14047 with a normal template parm in subsequent deduction. */
14059 {
14062 /* See through ARGUMENT_PACK_SELECT arguments. */
14065 }
14070 {
14072 /* If ARG is an argument pack, we don't actually want to
14073 perform a substitution here, because substitutions
14074 for argument packs are only done
14075 element-by-element. We can get to this point when
14076 substituting the type of a non-type template
14077 parameter pack, when that type actually contains
14078 template parameter packs from an outer template, e.g.,
14080 template<typename... Types> struct A {
14081 template<Types... Values> struct B { };
14082 }; */
14086 {
14092 return cp_build_qualified_type_real
14094 }
14096 {
14097 /* We are processing a type constructed from a
14098 template template parameter. */
14109 /* Consider this code:
14111 template <template <class> class Template>
14112 struct Internal {
14113 template <class Arg> using Bind = Template<Arg>;
14114 };
14116 template <template <class> class Template, class Arg>
14117 using Instantiate = Template<Arg>; //#0
14119 template <template <class> class Template,
14120 class Argument>
14121 using Bind =
14122 Instantiate<Internal<Template>::template Bind,
14123 Argument>; //#1
14125 When #1 is parsed, the
14126 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14127 parameter `Template' in #0 matches the
14128 UNBOUND_CLASS_TEMPLATE representing the argument
14129 `Internal<Template>::template Bind'; We then want
14130 to assemble the type `Bind<Argument>' that can't
14131 be fully created right now, because
14132 `Internal<Template>' not being complete, the Bind
14133 template cannot be looked up in that context. So
14134 we need to "store" `Bind<Argument>' for later
14135 when the context of Bind becomes complete. Let's
14136 store that in a TYPENAME_TYPE. */
14140 argvec),
14141 typename_type,
14142 complain);
14144 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14145 are resolving nested-types in the signature of a
14146 member function templates. Otherwise ARG is a
14147 TEMPLATE_DECL and is the real template to be
14148 instantiated. */
14156 complain);
14157 return cp_build_qualified_type_real
14159 }
14162 else
14163 /* TEMPLATE_PARM_INDEX. */
14165 }
14168 /* This can happen during the attempted tsubst'ing in
14169 unify. This means that we don't yet have any information
14170 about the template parameter in question. */
14173 /* If we get here, we must have been looking at a parm for a
14174 more deeply nested template. Make a new version of this
14175 template parameter, but with a lower level. */
14177 {
14182 {
14184 r = cp_build_qualified_type_real
14188 }
14195 /* Break infinite recursion when substituting the constraints
14197 else
14198 {
14209 {
14210 /* Propagate constraints on placeholders. */
14215 {
14218 }
14219 }
14222 /* We have reduced the level of the template
14223 template parameter, but not the levels of its
14224 template parameters, so canonical_type_parameter
14225 will not be able to find the canonical template
14226 template parameter for this level. Thus, we
14227 require structural equality checking to compare
14228 TEMPLATE_TEMPLATE_PARMs. */
14232 else
14236 {
14238 /* We might need to substitute into the types of non-type
14239 template parameters. */
14251 }
14252 }
14256 /* OK, now substitute the type of the non-type parameter. We
14257 couldn't do it earlier because it might be an auto parameter,
14258 and we wouldn't need to if we had an argument. */
14267 }
14270 }
14273 {
14281 {
14285 }
14288 {
14292 }
14295 {
14299 }
14305 }
14308 /* We should never be tsubsting a binfo. */
14312 /* A vector of template arguments. */
14318 {
14322 /* [temp.deduct]
14324 Type deduction may fail for any of the following
14325 reasons:
14327 -- Attempting to create a pointer to reference type.
14328 -- Attempting to create a reference to a reference type or
14329 a reference to void.
14331 Core issue 106 says that creating a reference to a reference
14332 during instantiation is no longer a cause for failure. We
14333 only enforce this check in strict C++98 mode. */
14337 {
14340 /* We keep track of the last time we issued this error
14341 message to avoid spewing a ton of messages during a
14342 single bad template instantiation. */
14345 {
14350 else
14353 }
14356 }
14360 {
14362 {
14365 type);
14366 else
14368 type);
14369 }
14371 }
14373 {
14377 }
14379 /* In C++0x, during template argument substitution, when there is an
14380 attempt to create a reference to a reference type, reference
14381 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14383 "If a template-argument for a template-parameter T names a type
14384 that is a reference to a type A, an attempt to create the type
14385 'lvalue reference to cv T' creates the type 'lvalue reference to
14386 A,' while an attempt to create the type type rvalue reference to
14387 cv T' creates the type T"
14388 */
14389 r = cp_build_reference_type
14392 else
14397 /* Will this ever be needed for TYPE_..._TO values? */
14401 }
14403 {
14406 {
14407 /* [temp.deduct]
14409 Type deduction may fail for any of the following
14410 reasons:
14412 -- Attempting to create "pointer to member of T" when T
14413 is not a class type. */
14417 }
14419 {
14423 }
14425 {
14429 }
14432 {
14433 /* The type of the implicit object parameter gets its
14434 cv-qualifiers from the FUNCTION_TYPE. */
14435 tree memptr;
14436 tree method_type
14441 complain);
14442 }
14443 else
14446 complain);
14447 }
14450 {
14451 tree fntype;
14452 tree specs;
14457 /* Substitute the exception specification. */
14465 }
14467 {
14472 /* As an optimization, we avoid regenerating the array type if
14473 it will obviously be the same as T. */
14477 /* These checks should match the ones in create_array_type_for_decl.
14479 [temp.deduct]
14481 The deduction may fail for any of the following reasons:
14483 -- Attempting to create an array with an element type that
14484 is void, a function type, or a reference type, or [DR337]
14485 an abstract class type. */
14491 {
14495 }
14503 {
14506 }
14509 }
14512 {
14524 {
14528 }
14530 {
14531 /* Normally, make_typename_type does not require that the CTX
14532 have complete type in order to allow things like:
14534 template <class T> struct S { typename S<T>::X Y; };
14536 But, such constructs have already been resolved by this
14537 point, so here CTX really should have complete type, unless
14538 it's a partial instantiation. */
14541 {
14545 }
14546 }
14553 {
14556 }
14559 {
14561 {
14565 else
14567 }
14569 {
14573 else
14575 }
14576 }
14578 return cp_build_qualified_type_real
14580 }
14583 {
14595 }
14598 {
14599 tree type;
14615 complain);
14616 }
14619 {
14620 tree type;
14631 {
14633 {
14637 }
14640 }
14651 else
14652 {
14656 /* In a template ~id could be either a complement expression
14657 or an unqualified-id naming a destructor; if instantiating
14658 it produces an expression, it's not an id-expression or
14659 member access. */
14662 }
14667 }
14670 {
14674 }
14678 {
14679 tree r;
14683 else
14691 }
14706 /* We should use one of the expression tsubsts for these codes. */
14712 }
14713 }
14715 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14716 expression on the left-hand side of the "." or "->" operator. We
14717 only do the lookup if we had a dependent BASELINK. Otherwise we
14718 adjust it onto the instantiated heirarchy. */
14720 static tree
14723 {
14735 {
14742 }
14749 {
14755 /* Treat as-if non-dependent below. */
14760 {
14766 }
14770 }
14771 else
14772 /* We're going to overwrite pieces below, make a duplicate. */
14775 /* If lookup found a single function, mark it as used at this point.
14776 (If lookup found multiple functions the one selected later by
14777 overload resolution will be marked as used at that point.) */
14779 {
14785 /* We might have instantiated an auto function. */
14787 }
14790 {
14791 /* Add back the template arguments, if present. */
14796 /* Update the conversion operator type. */
14798 }
14804 {
14806 qualifying_scope,
14807 object_type);
14809 /* We need to call adjust_result_of_qualified_name_lookup in case the
14810 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14811 so that we still get virtual function binding. */
14813 }
14816 }
14818 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14819 true if the qualified-id will be a postfix-expression in-and-of
14820 itself; false if more of the postfix-expression follows the
14821 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14822 of "&". */
14824 static tree
14828 {
14829 tree expr;
14830 tree scope;
14831 tree name;
14833 tree template_args;
14838 /* Figure out what name to look up. */
14841 {
14851 }
14852 else
14853 {
14856 }
14858 /* Substitute into the qualifying scope. When there are no ARGS, we
14859 are just trying to simplify a non-dependent expression. In that
14860 case the qualifying scope may be dependent, and, in any case,
14861 substituting will not help. */
14864 {
14867 }
14868 else
14872 {
14879 }
14882 {
14884 {
14885 /* A BIT_NOT_EXPR is used to represent a destructor. */
14887 {
14891 }
14892 else
14895 }
14896 else
14900 {
14902 {
14906 }
14908 }
14909 }
14912 {
14914 scope);
14915 /* Remember that there was a reference to this entity. */
14918 }
14921 {
14927 }
14930 {
14931 /* We may be repeating a check already done during parsing, but
14932 if it was well-formed and passed then, it will pass again
14933 now, and if it didn't, we wouldn't have got here. The case
14934 we want to catch is when we couldn't tell then, and can now,
14935 namely when templ prior to substitution was an
14936 identifier. */
14942 complain);
14943 else
14945 }
14951 {
14952 expr = (adjust_result_of_qualified_name_lookup
14954 expr = (finish_qualified_id_expr
14958 }
14960 /* Expressions do not generally have reference type. */
14962 /* However, if we're about to form a pointer-to-member, we just
14963 want the referenced member referenced. */
14971 }
14973 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14974 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14975 for tsubst. */
14977 static tree
14980 {
14987 {
14988 /* If we had an initializer but it
14989 instantiated to nothing,
14990 value-initialize the object. This will
14991 only occur when the initializer was a
14992 pack expansion where the parameter packs
14993 used in that expansion were of length
14994 zero. */
14996 complain);
15001 }
15004 }
15006 /* Like tsubst, but deals with expressions. This function just replaces
15007 template parms; to finish processing the resultant expression, use
15008 tsubst_copy_and_build or tsubst_expr. */
15010 static tree
15012 {
15014 tree r;
15022 {
15027 {
15028 /* We get here for a use of 'this' in an NSDMI. */
15032 /* This can happen for a parameter name used later in a function
15033 declaration (such as in a late-specified return type). Just
15034 make a dummy decl, since it's only used for its type. */
15037 /* Give it the template pattern as its context; its true context
15038 hasn't been instantiated yet and this is good enough for
15039 mangling. */
15041 }
15050 {
15051 tree enum_type;
15052 tree v;
15056 /* There is no need to substitute into namespace-scope
15057 enumerators. */
15060 /* If ARGS is NULL, then T is known to be non-dependent. */
15064 /* Unfortunately, we cannot just call lookup_name here.
15065 Consider:
15067 template <int I> int f() {
15068 enum E { a = I };
15069 struct S { void g() { E e = a; } };
15070 };
15072 When we instantiate f<7>::S::g(), say, lookup_name is not
15073 clever enough to find f<7>::a. */
15074 enum_type
15084 /* We didn't find the name. That should never happen; if
15085 name-lookup found it during preliminary parsing, we
15086 should find it again here during instantiation. */
15088 }
15093 {
15094 tree ctx;
15099 {
15102 {
15106 }
15108 }
15109 }
15119 {
15122 {
15123 /* First try name lookup to find the instantiation. */
15126 {
15127 /* Make sure that the one we found is the one we want. */
15131 }
15135 else
15136 {
15137 /* This can happen for a variable used in a
15138 late-specified return type of a local lambda, or for a
15139 local static or constant. Building a new VAR_DECL
15140 should be OK in all those cases. */
15143 /* Avoid infinite recursion (79640). */
15146 {
15147 /* We can't call cp_finish_decl, so handle the
15148 initializer by hand. */
15163 }
15170 }
15171 /* Remember this for subsequent uses. */
15174 }
15177 }
15178 else
15188 /* An OVERLOAD will always be a non-dependent overload set; an
15189 overload set from function scope will just be represented with an
15190 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15192 /* We must have marked any lookups as persistent. */
15208 {
15209 /* Template template argument like the following example need
15210 special treatment:
15212 template <template <class> class TT> struct C {};
15213 template <class T> struct D {
15214 template <class U> struct E {};
15215 C<E> c; // #1
15216 };
15217 D<int> d; // #2
15219 We are processing the template argument `E' in #1 for
15220 the template instantiation #2. Originally, `E' is a
15221 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15222 have to substitute this with one having context `D<int>'. */
15226 {
15227 /* When rewriting a constructor into a deduction guide, a
15228 non-dependent name can become dependent, so memtmpl<args>
15229 becomes context::template memtmpl<args>. */
15233 }
15235 }
15236 else
15237 /* Ordinary template template argument. */
15242 {
15243 /* Handle location wrappers by substituting the wrapped node
15244 first, *then* reusing the resulting type. Doing the type
15245 first ensures that we handle template parameters and
15246 parameter pack expansions. */
15250 }
15260 {
15264 }
15269 {
15278 /* We only want to compute the number of arguments. */
15281 else
15288 {
15290 /* Set TREE_USED for the benefit of -Wunused. */
15294 }
15302 {
15307 else
15313 else
15316 }
15317 else
15319 }
15321 {
15329 }
15330 /* Fall through */
15346 {
15350 }
15353 {
15354 tree object;
15355 tree name;
15360 {
15364 }
15367 {
15377 }
15382 in_decl);
15383 else
15386 }
15424 {
15428 }
15431 {
15436 }
15439 {
15443 }
15446 {
15454 }
15460 {
15467 }
15470 {
15477 }
15480 {
15487 }
15490 {
15491 /* Substituted template arguments */
15500 }
15503 {
15523 }
15548 /* Fall through. */
15551 {
15554 }
15555 else
15559 /* This is handled by tsubst_copy_and_build. */
15563 {
15567 }
15570 /* We shouldn't have built any of these during initial template
15571 generation. Instead, they should be built during instantiation
15572 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15576 {
15586 }
15604 {
15605 /* Instantiate any typedefs in the type. */
15610 }
15613 /* These can sometimes show up in a partial instantiation, but never
15614 involve template parms. */
15630 /* ??? There's no point in copying it for now, but maybe some
15631 day it will contain more information, such as a pointer back
15632 to the containing function, inlined copy or so. */
15636 /* We shouldn't get here, but keep going if !flag_checking. */
15640 }
15641 }
15643 /* Helper function for tsubst_omp_clauses, used for instantiation of
15644 OMP_CLAUSE_DECL of clauses. */
15646 static tree
15648 tree in_decl)
15649 {
15653 /* Handle an OpenMP array section represented as a TREE_LIST (or
15654 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15655 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15656 TREE_LIST. We can handle it exactly the same as an array section
15657 (purpose, value, and a chain), even though the nomenclature
15658 (low_bound, length, etc) is different. */
15660 {
15661 tree low_bound
15667 in_decl);
15676 }
15679 /* Undo convert_from_reference tsubst_expr could have called. */
15685 }
15687 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15689 static tree
15692 {
15697 {
15703 {
15706 {
15712 }
15713 /* FALLTHRU */
15728 in_decl);
15760 {
15763 {
15770 }
15771 else
15773 }
15776 in_decl);
15782 in_decl);
15790 in_decl);
15792 {
15795 }
15800 else
15803 in_decl,
15827 }
15830 {
15840 /* tsubst_expr on SCOPE_REF results in returning
15841 finish_non_static_data_member result. Undo that here. */
15845 {
15850 {
15854 CASE_CONVERT:
15863 /* FALLTHRU */
15867 }
15868 }
15874 {
15877 {
15880 }
15881 }
15885 }
15886 }
15890 {
15895 {
15898 }
15899 }
15901 }
15903 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15905 static tree
15907 tree in_decl)
15908 {
15909 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15929 {
15932 else
15933 {
15937 }
15938 }
15943 #undef RECUR
15944 }
15946 /* Used to temporarily communicate the list of #pragma omp parallel
15947 clauses to #pragma omp for instantiation if they are combined
15948 together. */
15952 /* Substitute one OMP_FOR iterator. */
15954 static void
15959 {
15960 #define RECUR(NODE) \
15961 tsubst_expr ((NODE), args, complain, in_decl, \
15962 integral_constant_expression_p)
15969 {
15972 }
15978 {
15979 /* We need to jump through some hoops to handle declarations in the
15980 init-statement, since we might need to handle auto deduction,
15981 but we need to keep control of initialization. */
15985 }
15986 else
15987 {
15989 {
15992 {
15996 {
16000 CASE_CONVERT:
16008 {
16011 }
16012 /* FALLTHRU */
16016 }
16017 }
16018 }
16019 else
16021 }
16032 {
16034 {
16035 /* Declare the variable, but don't let that initialize it. */
16040 }
16045 {
16050 }
16051 else
16058 }
16061 {
16062 /* Declare and initialize the variable. */
16065 }
16067 {
16071 {
16073 {
16079 {
16082 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16087 }
16090 {
16092 decl);
16094 }
16097 {
16099 decl);
16101 }
16102 else
16104 }
16107 }
16109 {
16114 {
16117 }
16118 }
16119 }
16122 {
16126 }
16127 else
16131 {
16142 {
16150 }
16151 else
16157 {
16163 }
16167 {
16175 }
16176 else
16182 }
16188 #undef RECUR
16189 }
16191 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16192 of OMP_TARGET's body. */
16194 static tree
16196 {
16199 {
16208 }
16210 }
16212 /* Helper function for tsubst_expr. For decomposition declaration
16213 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16214 also the corresponding decls representing the identifiers
16215 of the decomposition declaration. Return DECL if successful
16216 or error_mark_node otherwise, set *FIRST to the first decl
16217 in the list chained through DECL_CHAIN and *CNT to the number
16218 of such decls. */
16220 static tree
16224 {
16229 decl2
16234 {
16236 {
16239 }
16251 else
16252 {
16256 }
16263 {
16266 }
16267 else
16269 }
16272 }
16274 /* Like tsubst_copy for expressions, etc. but also does semantic
16275 processing. */
16277 tree
16280 {
16281 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16282 #define RECUR(NODE) \
16283 tsubst_expr ((NODE), args, complain, in_decl, \
16284 integral_constant_expression_p)
16287 tree r;
16288 location_t loc;
16300 {
16302 {
16303 tree_stmt_iterator i;
16307 }
16322 else
16332 {
16334 tree init;
16340 {
16350 else
16352 }
16355 {
16356 /* We're in tsubst_lambda_expr, we've already inserted a new
16357 capture proxy, so look it up and register it. */
16358 tree inst;
16360 {
16361 inst = (retrieve_local_specialization
16364 }
16365 else
16366 {
16370 }
16373 }
16376 /* Don't copy the old closure; we'll create a new one in
16377 tsubst_lambda_expr. */
16379 else
16380 {
16384 {
16385 /* By marking the declaration as instantiated, we avoid
16386 trying to instantiate it. Since instantiate_decl can't
16387 handle local variables, and since we've already done
16388 all that needs to be done, that's the right thing to
16389 do. */
16394 /* Anonymous aggregates are a special case. */
16397 {
16400 {
16404 }
16406 }
16412 {
16417 }
16418 else
16419 {
16424 {
16425 /* For __PRETTY_FUNCTION__ we have to adjust the
16426 initializer. */
16430 }
16431 else
16435 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16440 {
16442 tree first;
16443 tree ndecl
16451 }
16452 else
16454 }
16455 }
16456 }
16459 }
16469 {
16473 }
16478 {
16479 /* Construct another range_for, if this is not a final
16480 substitution (for inside inside a generic lambda of a
16481 template). Otherwise convert to a regular for. */
16483 stmt = (processing_template_decl
16499 {
16503 }
16504 else
16505 {
16511 }
16517 }
16524 {
16528 }
16534 {
16538 }
16553 {
16554 /* We're partially instantiating a generic lambda, but the condition
16555 of the constexpr if is still dependent. Don't substitute into the
16556 branches now, just remember the template arguments. */
16564 }
16567 else
16568 {
16575 }
16581 {
16590 }
16598 else
16606 else
16627 {
16634 }
16638 {
16640 tree label;
16647 }
16653 /* Computed goto's must be tsubst'd into. On the other hand,
16654 non-computed gotos must not be; the identifier in question
16655 will have no binding. */
16657 else
16663 {
16679 }
16684 {
16689 }
16690 else
16691 {
16696 else
16703 else
16709 else
16711 }
16715 {
16719 {
16721 /* Prevent instantiate_decl from trying to instantiate
16722 this variable. We've already done all that needs to be
16723 done. */
16726 }
16731 }
16737 {
16738 /* Local classes are not independent templates; they are
16739 instantiated along with their containing function. And this
16740 way we don't have to deal with pushing out of one local class
16741 to instantiate a member of another local class. */
16742 /* Closures are handled by the LAMBDA_EXPR. */
16752 }
16756 {
16757 tree condition;
16760 condition =
16762 args,
16771 }
16777 in_decl);
16812 {
16825 in_decl);
16827 {
16834 }
16846 integral_constant_expression_p);
16857 else
16858 {
16866 }
16870 }
16875 /* FALLTHRU */
16882 in_decl);
16899 in_decl);
16910 {
16913 {
16914 /* For combined target teams, ensure the num_teams and
16915 thread_limit clause expressions are evaluated on the host,
16916 before entering the target construct. */
16917 tree c;
16923 {
16932 OMP_CLAUSE_FIRSTPRIVATE);
16936 }
16937 }
16938 }
16998 {
17003 {
17006 }
17012 }
17013 else
17014 {
17021 {
17024 }
17027 {
17032 {
17035 }
17041 }
17042 else
17043 {
17047 }
17050 }
17054 {
17060 {
17064 {
17069 }
17073 }
17074 else
17075 {
17080 }
17081 }
17085 {
17089 }
17102 /* If the first operand was a statement, we're done with it. */
17106 complain));
17120 integral_constant_expression_p));
17121 }
17124 out:
17127 #undef RECUR
17128 #undef RETURN
17129 }
17131 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17132 function. For description of the body see comment above
17133 cp_parser_omp_declare_reduction_exprs. */
17135 static void
17137 {
17143 tree_stmt_iterator tsi;
17154 {
17173 }
17175 {
17195 }
17196 }
17198 /* T is a postfix-expression that is not being used in a function
17199 call. Return the substituted version of T. */
17201 static tree
17203 tsubst_flags_t complain,
17204 tree in_decl)
17205 {
17209 else
17215 }
17217 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17218 instantiation context. Instantiating a pack expansion containing a lambda
17219 might result in multiple lambdas all based on the same lambda in the
17220 template. */
17222 tree
17224 {
17238 else
17246 {
17258 else
17263 {
17272 }
17273 else
17274 {
17280 }
17281 }
17285 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17303 else
17304 {
17305 /* Fix the type of 'this'. */
17311 {
17315 }
17316 else
17317 {
17321 }
17323 /* Let finish_function set this. */
17329 else
17330 /* Still increment function_depth so that we don't GC in the
17331 middle of an expression. */
17347 else
17350 /* The capture list was built up in reverse order; fix that now. */
17357 }
17364 }
17366 /* Like tsubst but deals with expressions and performs semantic
17367 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17369 tree
17371 tree args,
17372 tsubst_flags_t complain,
17373 tree in_decl,
17376 {
17377 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17378 #define RECUR(NODE) \
17379 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17381 integral_constant_expression_p)
17384 location_t loc;
17393 /* N3276 decltype magic only applies to calls at the top level or on the
17394 right side of a comma. */
17399 {
17402 /* Fall through. */
17404 {
17405 tree decl;
17406 cp_id_kind idk;
17411 {
17414 }
17416 /* Look up the name. */
17419 /* By convention, expressions use ERROR_MARK_NODE to indicate
17420 failure, not NULL_TREE. */
17426 integral_constant_expression_p,
17434 input_location);
17438 {
17442 }
17444 }
17447 {
17448 tree object;
17458 {
17463 }
17469 {
17472 }
17473 else
17480 else
17482 }
17485 {
17489 {
17490 /* A type conversion to reference type will be enclosed in
17491 such an indirect ref, but the substitution of the cast
17492 will have also added such an indirect ref. */
17494 }
17495 else
17503 }
17506 {
17510 }
17513 {
17517 {
17522 }
17524 /* We'll pass this to convert_nontype_argument again, we don't need
17525 to actually perform any conversion here. */
17531 flags));
17532 }
17535 {
17541 }
17548 {
17549 tree type;
17555 {
17560 }
17567 {
17585 }
17588 }
17621 else
17623 in_decl);
17658 {
17665 tree r = build_x_binary_op
17667 op0,
17669 ? ERROR_MARK
17671 op1,
17673 ? ERROR_MARK
17681 }
17684 {
17688 }
17704 /* Fall through */
17707 {
17708 tree r;
17714 {
17715 /* When there are no ARGS, we are trying to evaluate a
17716 non-dependent expression from the parser. Trying to do
17717 the substitutions may not work. */
17720 }
17721 else
17722 {
17727 else
17730 /*integral_constant_expression_p=*/
17734 }
17738 else
17742 {
17744 {
17746 {
17750 }
17751 else
17755 }
17757 }
17759 }
17762 {
17772 }
17788 {
17792 tree r = build_x_modify_expr
17795 /* TREE_NO_WARNING must be set if either the expression was
17796 parenthesized or it uses an operator such as >>= rather
17797 than plain assignment. In the former case, it was already
17798 set and must be copied. In the latter case,
17799 build_x_modify_expr sets it and it must not be reset
17800 here. */
17805 }
17810 /* Remember that there was a reference to this entity. */
17817 {
17822 tree ret;
17826 else
17827 {
17831 }
17833 /* If there was an initializer in the original tree, but it
17834 instantiated to an empty list, then we should pass a
17835 non-NULL empty vector to tell build_new that it was an
17836 empty initializer() rather than no initializer. This can
17837 only happen when the initializer is a pack expansion whose
17838 parameter packs are of length zero. */
17841 else
17842 {
17846 else
17847 {
17850 }
17851 }
17857 complain);
17865 }
17868 {
17874 complain));
17875 }
17878 {
17882 integral_constant_expression_p);
17884 op0,
17887 }
17890 {
17891 tree function;
17896 tree ret;
17899 /* Internal function with no arguments. */
17903 /* When we parsed the expression, we determined whether or
17904 not Koenig lookup should be performed. */
17907 {
17910 }
17912 {
17917 }
17919 {
17920 /* Do nothing; calling tsubst_copy_and_build on an identifier
17921 would incorrectly perform unqualified lookup again.
17923 Note that we can also have an IDENTIFIER_NODE if the earlier
17924 unqualified lookup found a member function; in that case
17925 koenig_p will be false and we do want to do the lookup
17926 again to find the instantiated member function.
17928 FIXME but doing that causes c++/15272, so we need to stop
17929 using IDENTIFIER_NODE in that situation. */
17931 }
17932 else
17933 {
17935 {
17941 }
17942 else
17947 /* Avoid error about taking the address of a constructor. */
17951 in_decl,
17953 integral_constant_expression_p);
17957 }
17962 {
17967 else
17968 {
17969 /* Expand the pack expansion and push each entry onto
17970 CALL_ARGS. */
17973 {
17978 {
17983 }
17984 }
17985 else
17986 {
17987 /* A partial substitution. Add one entry. */
17989 }
17990 }
17991 }
17993 /* We do not perform argument-dependent lookup if normal
17994 lookup finds a non-function, in accordance with the
17995 expected resolution of DR 218. */
17998 /* If lookup found a member function, the Koenig lookup is
17999 not appropriate, even if an unqualified-name was used
18000 to denote the function. */
18003 /* Only do this when substitution turns a dependent call
18004 into a non-dependent call. */
18012 {
18014 {
18015 /* For backwards compatibility and good diagnostics, try
18016 the unqualified lookup again if we aren't in SFINAE
18017 context. */
18018 tree unq = (tsubst_copy_and_build
18020 integral_constant_expression_p));
18022 {
18025 }
18028 {
18029 /* In a lambda fn, we have to be careful to not
18030 introduce new this captures. Legacy code can't
18031 be using lambdas anyway, so it's ok to be
18032 stricter. */
18037 "and no declarations were found by "
18038 "argument-dependent lookup at the point "
18045 else
18049 {
18060 {
18062 input_location);
18064 "declarations in dependent base %qT are "
18070 else
18074 }
18075 else
18077 "%qD declared here, later in the "
18080 {
18083 }
18084 }
18087 }
18088 }
18090 {
18095 }
18096 }
18098 /* Remember that there was a reference to this entity. */
18102 {
18105 }
18107 /* Put back tf_decltype for the actual call. */
18112 {
18116 {
18118 "wrong number of arguments to "
18121 }
18122 else
18124 input_location),
18129 /* Unsupported internal function with arguments. */
18131 }
18134 complain);
18136 {
18151 complain);
18152 else
18153 ret = (build_new_method_call
18158 complain));
18159 }
18160 else
18163 koenig_p,
18164 complain);
18169 {
18175 {
18181 {
18184 else
18186 /* The thunk location is not interesting. */
18188 }
18189 }
18190 }
18193 }
18196 {
18202 {
18204 {
18209 }
18210 else
18211 {
18216 }
18218 }
18219 else
18220 {
18223 }
18228 }
18231 {
18236 input_location));
18237 }
18240 {
18248 {
18249 /* We have pack expansions, so expand those and
18250 create a new list out of it. */
18253 tree chain;
18256 /* Expand the argument expressions. */
18264 /* Build the rest of the list. */
18269 /* Determine the number of arguments. */
18271 {
18274 }
18277 else
18278 {
18279 /* Since we only performed a partial substitution into
18280 the argument pack, we only RETURN (a single list
18281 node. */
18288 }
18290 /* Convert the argument vectors into a TREE_LIST */
18293 {
18294 /* Grab the Ith values. */
18295 i--;
18298 value
18302 /* Build the list (backwards). */
18304 }
18307 }
18323 }
18326 {
18327 tree object;
18328 tree object_type;
18329 tree member;
18330 tree r;
18334 /* Remember that there was a reference to this entity. */
18345 else
18351 {
18356 }
18360 {
18362 {
18367 {
18370 }
18372 {
18377 }
18378 }
18379 }
18382 {
18383 /* Lookup the template functions now that we know what the
18384 scope is. */
18392 {
18395 args);
18396 member = (adjust_result_of_qualified_name_lookup
18398 object_type));
18399 }
18400 else
18401 {
18403 input_location);
18405 }
18406 }
18410 {
18412 {
18416 else
18419 }
18421 }
18425 complain);
18429 }
18436 {
18444 tree r;
18449 /* We do not want to process the index of aggregate
18450 initializers as they are identifier nodes which will be
18451 looked up by digest_init. */
18457 {
18459 /* An identifier index is looked up in the type
18460 being initialized, not the current scope. */
18465 {
18466 /* Substitute into the pack expansion. */
18468 in_decl);
18472 ;
18474 /* Just move the argument into place. */
18476 else
18477 {
18478 /* Update the length of the final CONSTRUCTOR
18479 arguments vector, and note that we will need to
18480 copy.*/
18483 }
18484 }
18485 else
18487 }
18490 {
18495 {
18497 {
18502 }
18503 else
18505 }
18506 }
18512 {
18517 }
18521 }
18524 {
18527 {
18530 }
18531 else
18532 {
18535 }
18536 }
18541 /* Fall through */
18544 {
18546 /* ??? We're doing a subset of finish_id_expression here. */
18548 && !processing_template_decl
18549 && !cp_unevaluated_operand
18552 {
18554 /* Replace an evaluated use of the thread_local variable with
18555 a call to its wrapper. */
18557 }
18562 /* If the original type was a reference, we'll be wrapped in
18563 the appropriate INDIRECT_REF. */
18566 }
18569 {
18573 }
18576 {
18577 tree object_ptr
18584 }
18591 {
18602 }
18605 {
18611 integral_constant_expression_p);
18615 /* If the resulting list of expression statement is empty,
18616 fold it further into void_node. */
18621 }
18624 {
18628 }
18631 /* We can get here for a constant initializer of non-dependent type.
18632 FIXME stop folding in cp_parser_initializer_clause. */
18633 {
18635 complain);
18637 }
18641 integral_constant_expression_p));
18647 {
18652 complain));
18653 }
18660 /* We should only see these for location wrapper nodes, or within
18661 instantiate_non_dependent_expr (when args is NULL_TREE). */
18666 /* fallthrough. */
18669 /* Handle Objective-C++ constructs, if appropriate. */
18670 {
18671 tree subst
18676 }
18678 }
18680 #undef RECUR
18681 #undef RETURN
18682 out:
18685 }
18687 /* Verify that the instantiated ARGS are valid. For type arguments,
18688 make sure that the type's linkage is ok. For non-type arguments,
18689 make sure they are constants if they are integral or enumerations.
18690 Emit an error under control of COMPLAIN, and return TRUE on error. */
18692 static bool
18694 {
18698 {
18708 }
18710 {
18711 /* [basic.link]: A name with no linkage (notably, the name
18712 of a class or enumeration declared in a local scope)
18713 shall not be used to declare an entity with linkage.
18714 This implies that names with no linkage cannot be used as
18715 template arguments
18717 DR 757 relaxes this restriction for C++0x. */
18722 {
18723 /* DR 488 makes use of a type with no linkage cause
18724 type deduction to fail. */
18726 {
18729 else
18732 }
18734 }
18735 /* In order to avoid all sorts of complications, we do not
18736 allow variably-modified types as template arguments. */
18738 {
18742 }
18743 }
18744 /* Class template and alias template arguments should be OK. */
18746 ;
18747 /* A non-type argument of integral or enumerated type must be a
18748 constant. */
18753 {
18757 }
18759 }
18761 static bool
18763 {
18768 {
18771 }
18775 }
18777 /* We're out of SFINAE context now, so generate diagnostics for the access
18778 errors we saw earlier when instantiating D from TMPL and ARGS. */
18780 static void
18782 {
18794 }
18796 /* Instantiate the indicated variable, function, or alias template TMPL with
18797 the template arguments in TARG_PTR. */
18799 static tree
18801 {
18803 tree fndecl;
18804 tree gen_tmpl;
18805 tree spec;
18813 /* If this function is a clone, handle it specially. */
18815 {
18816 tree spec;
18817 tree clone;
18819 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18820 DECL_CLONED_FUNCTION. */
18826 /* Look for the clone. */
18830 /* We should always have found the clone by now. */
18833 }
18838 /* Check to see if we already have this specialization. */
18842 /* targ_ptr only has the innermost template args, so add the outer ones
18843 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18844 the case of a non-dependent call within a template definition). */
18845 targ_ptr = (add_outermost_template_args
18847 targ_ptr));
18849 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18850 but it doesn't seem to be on the hot path. */
18859 {
18861 {
18865 }
18867 }
18870 complain))
18873 /* We are building a FUNCTION_DECL, during which the access of its
18874 parameters and return types have to be checked. However this
18875 FUNCTION_DECL which is the desired context for access checking
18876 is not built yet. We solve this chicken-and-egg problem by
18877 deferring all checks until we have the FUNCTION_DECL. */
18880 /* Instantiation of the function happens in the context of the function
18881 template, not the context of the overload resolution we're doing. */
18883 /* If there are dependent arguments, e.g. because we're doing partial
18884 ordering, make sure processing_template_decl stays set. */
18888 {
18892 }
18898 {
18899 /* We need to determine if we're using a partial or explicit
18900 specialization now, because the type of the variable could be
18901 different. */
18907 {
18912 }
18913 }
18915 /* Substitute template parameters to obtain the specialization. */
18923 {
18926 }
18928 /* The DECL_TI_TEMPLATE should always be the immediate parent
18929 template, not the most general template. */
18933 /* Now we know the specialization, compute access previously
18934 deferred. Do no access control for inheriting constructors,
18935 as we already checked access for the inherited constructor. */
18938 {
18943 }
18946 /* If we've just instantiated the main entry point for a function,
18947 instantiate all the alternate entry points as well. We do this
18948 by cloning the instantiation of the main entry point, not by
18949 instantiating the template clones. */
18954 {
18956 {
18957 /* Remember to reinstantiate when we're out of SFINAE so the user
18958 can see the errors. */
18960 }
18962 }
18964 }
18966 /* Wrapper for instantiate_template_1. */
18968 tree
18970 {
18971 tree ret;
18976 }
18978 /* Instantiate the alias template TMPL with ARGS. Also push a template
18979 instantiation level, which instantiate_template doesn't do because
18980 functions and variables have sufficient context established by the
18981 callers. */
18983 static tree
18985 {
18992 {
18995 }
18997 args =
19005 /* We can't free this if a pending_template entry or last_error_tinst_level
19006 is pointing at it. */
19012 }
19014 /* PARM is a template parameter pack for FN. Returns true iff
19015 PARM is used in a deducible way in the argument list of FN. */
19017 static bool
19019 {
19022 {
19024 tree packs;
19030 {
19031 /* The template parameter pack is used in a function parameter
19032 pack. If this is the end of the parameter list, the
19033 template parameter pack is deducible. */
19036 else
19037 /* Otherwise, not. Well, it could be deduced from
19038 a non-pack parameter, but doing so would end up with
19039 a deduction mismatch, so don't bother. */
19041 }
19042 }
19043 /* The template parameter pack isn't used in any function parameter
19044 packs, but it might be used deeper, e.g. tuple<Args...>. */
19046 }
19048 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19049 NARGS elements of the arguments that are being used when calling
19050 it. TARGS is a vector into which the deduced template arguments
19051 are placed.
19053 Returns either a FUNCTION_DECL for the matching specialization of FN or
19054 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19055 true, diagnostics will be printed to explain why it failed.
19057 If FN is a conversion operator, or we are trying to produce a specific
19058 specialization, RETURN_TYPE is the return type desired.
19060 The EXPLICIT_TARGS are explicit template arguments provided via a
19061 template-id.
19063 The parameter STRICT is one of:
19065 DEDUCE_CALL:
19066 We are deducing arguments for a function call, as in
19067 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19068 deducing arguments for a call to the result of a conversion
19069 function template, as in [over.call.object].
19071 DEDUCE_CONV:
19072 We are deducing arguments for a conversion function, as in
19073 [temp.deduct.conv].
19075 DEDUCE_EXACT:
19076 We are deducing arguments when doing an explicit instantiation
19077 as in [temp.explicit], when determining an explicit specialization
19078 as in [temp.expl.spec], or when taking the address of a function
19079 template, as in [temp.deduct.funcaddr]. */
19081 tree
19083 tree explicit_targs,
19084 tree targs,
19087 tree return_type,
19088 unification_kind_t strict,
19092 {
19093 tree parms;
19094 tree fntype;
19107 tree tinst;
19113 full_targs = (add_outermost_template_args
19115 targs));
19120 /* In C++0x, it's possible to have a function template whose type depends
19121 on itself recursively. This is most obvious with decltype, but can also
19122 occur with enumeration scope (c++/48969). So we need to catch infinite
19123 recursion and reject the substitution at deduction time; this function
19124 will return error_mark_node for any repeated substitution.
19126 This also catches excessive recursion such as when f<N> depends on
19127 f<N-1> across all integers, and returns error_mark_node for all the
19128 substitutions back up to the initial one.
19130 This is, of course, not reentrant. */
19140 {
19141 /* [temp.deduct]
19143 The specified template arguments must match the template
19144 parameters in kind (i.e., type, nontype, template), and there
19145 must not be more arguments than there are parameters;
19146 otherwise type deduction fails.
19148 Nontype arguments must match the types of the corresponding
19149 nontype template parameters, or must be convertible to the
19150 types of the corresponding nontype parameters as specified in
19151 _temp.arg.nontype_, otherwise type deduction fails.
19153 All references in the function type of the function template
19154 to the corresponding template parameters are replaced by the
19155 specified template argument values. If a substitution in a
19156 template parameter or in the function type of the function
19157 template results in an invalid type, type deduction fails. */
19168 explicit_targs);
19170 /* Adjust any explicit template arguments before entering the
19171 substitution context. */
19172 explicit_targs
19174 complain,
19180 /* Substitute the explicit args into the function type. This is
19181 necessary so that, for instance, explicitly declared function
19182 arguments can match null pointed constants. If we were given
19183 an incomplete set of explicit args, we must not do semantic
19184 processing during substitution as we could create partial
19185 instantiations. */
19187 {
19192 /* Dig out the actual parm. */
19195 {
19198 }
19200 {
19203 }
19206 /* No explicit argument for this template parameter. */
19210 {
19211 /* Mark the argument pack as "incomplete". We could
19212 still deduce more arguments during unification.
19213 We remove this mark in type_unification_real. */
19215 {
19219 }
19221 /* We have some incomplete argument packs. */
19223 }
19224 }
19228 {
19231 }
19234 /* Ignore any access checks; we'll see them again in
19235 instantiate_template and they might have the wrong
19236 access path at this point. */
19248 /* Place the explicitly specified arguments in TARGS. */
19252 }
19254 /* Never do unification on the 'this' parameter. */
19258 {
19259 /* We're deducing for a call to the result of a template conversion
19260 function. The parms we really want are in return_type. */
19264 }
19266 {
19275 }
19277 /* We allow incomplete unification without an error message here
19278 because the standard doesn't seem to explicitly prohibit it. Our
19279 callers must be ready to deal with unification failures in any
19280 event. */
19283 /* If we aren't explaining yet, push tinst context so we can see where
19284 any errors (e.g. from class instantiations triggered by instantiation
19285 of default template arguments) come from. If we are explaining, this
19286 context is redundant. */
19288 {
19291 }
19293 /* type_unification_real will pass back any access checks from default
19294 template argument substitution. */
19306 /* Now that we have bindings for all of the template arguments,
19307 ensure that the arguments deduced for the template template
19308 parameters have compatible template parameter lists. We cannot
19309 check this property before we have deduced all template
19310 arguments, because the template parameter types of a template
19311 template parameter might depend on prior template parameters
19312 deduced after the template template parameter. The following
19313 ill-formed example illustrates this issue:
19315 template<typename T, template<T> class C> void f(C<5>, T);
19317 template<int N> struct X {};
19319 void g() {
19320 f(X<5>(), 5l); // error: template argument deduction fails
19321 }
19323 The template parameter list of 'C' depends on the template type
19324 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19325 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19326 time that we deduce 'C'. */
19329 {
19332 }
19334 /* All is well so far. Now, check:
19336 [temp.deduct]
19338 When all template arguments have been deduced, all uses of
19339 template parameters in nondeduced contexts are replaced with
19340 the corresponding deduced argument values. If the
19341 substitution results in an invalid type, as described above,
19342 type deduction fails. */
19345 {
19348 }
19350 /* Also collect access checks from the instantiation. */
19363 /* Now perform any access checks encountered during substitution. */
19370 /* If we're looking for an exact match, check that what we got
19371 is indeed an exact match. It might not be if some template
19372 parameters are used in non-deduced contexts. But don't check
19373 for an exact match if we have dependent template arguments;
19374 in that case we're doing partial ordering, and we already know
19375 that we have two candidates that will provide the actual type. */
19377 {
19381 tree sarg
19387 {
19391 }
19392 }
19394 /* After doing deduction with the inherited constructor, actually return an
19395 instantiation of the inheriting constructor. */
19401 fail:
19404 {
19406 /* Reset once we're all the way out. */
19408 }
19410 /* We can't free this if a pending_template entry or last_error_tinst_level
19411 is pointing at it. */
19417 }
19419 /* Adjust types before performing type deduction, as described in
19420 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19421 sections are symmetric. PARM is the type of a function parameter
19422 or the return type of the conversion function. ARG is the type of
19423 the argument passed to the call, or the type of the value
19424 initialized with the result of the conversion function.
19425 ARG_EXPR is the original argument expression, which may be null. */
19427 static int
19431 tree arg_expr)
19432 {
19436 {
19441 /* Swap PARM and ARG throughout the remainder of this
19442 function; the handling is precisely symmetric since PARM
19443 will initialize ARG rather than vice versa. */
19448 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19449 too, but here handle it by stripping the reference from PARM
19450 rather than by adding it to ARG. */
19458 /* Nothing else to do in this case. */
19463 }
19466 {
19467 /* [temp.deduct.call]
19469 If P is not a reference type:
19471 --If A is an array type, the pointer type produced by the
19472 array-to-pointer standard conversion (_conv.array_) is
19473 used in place of A for type deduction; otherwise,
19475 --If A is a function type, the pointer type produced by
19476 the function-to-pointer standard conversion
19477 (_conv.func_) is used in place of A for type deduction;
19478 otherwise,
19480 --If A is a cv-qualified type, the top level
19481 cv-qualifiers of A's type are ignored for type
19482 deduction. */
19487 else
19489 }
19491 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19492 reference to a cv-unqualified template parameter that does not represent a
19493 template parameter of a class template (during class template argument
19494 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19495 an lvalue, the type "lvalue reference to A" is used in place of A for type
19496 deduction. */
19503 /* try_one_overload doesn't provide an arg_expr, but
19504 functions are always lvalues. */
19508 /* [temp.deduct.call]
19510 If P is a cv-qualified type, the top level cv-qualifiers
19511 of P's type are ignored for type deduction. If P is a
19512 reference type, the type referred to by P is used for
19513 type deduction. */
19516 {
19519 }
19521 /* DR 322. For conversion deduction, remove a reference type on parm
19522 too (which has been swapped into ARG). */
19527 }
19529 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19530 template which does contain any deducible template parameters; check if
19531 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19532 unify_one_argument. */
19534 static int
19537 {
19538 tree type;
19542 else
19549 {
19553 }
19555 {
19560 }
19564 else
19566 }
19570 /* Returns true iff the expression EXPR is one from which a template
19571 argument can be deduced. In other words, if it's an undecorated
19572 use of a template non-type parameter. */
19574 static bool
19576 {
19577 /* Strip implicit conversions. */
19581 }
19583 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19584 deducible way; that is, if it has a max value of <PARM> - 1. */
19586 static bool
19588 {
19597 }
19599 /* Returns true iff the template arguments ARGS use a template parameter
19600 in a deducible way. */
19602 static bool
19604 {
19606 {
19611 else
19612 {
19619 else
19621 }
19624 }
19626 }
19628 /* Returns true iff TYPE contains any deducible references to template
19629 parameters, as per 14.8.2.5. */
19631 static bool
19633 {
19637 /* T
19638 cv-list T
19639 TT<T>
19640 TT<i>
19641 TT<> */
19646 /* T*
19647 T&
19648 T&& */
19652 /* T[integer-constant ]
19653 type [i] */
19658 /* T type ::*
19659 type T::*
19660 T T::*
19661 T (type ::*)()
19662 type (T::*)()
19663 type (type ::*)(T)
19664 type (T::*)(T)
19665 T (type ::*)(T)
19666 T (T::*)()
19667 T (T::*)(T) */
19670 || (uses_deducible_template_parms
19673 /* template-name <T> (where template-name refers to a class template)
19674 template-name <i> (where template-name refers to a class template) */
19681 /* type (T)
19682 T()
19683 T(T) */
19686 {
19695 }
19698 }
19700 /* Subroutine of type_unification_real and unify_pack_expansion to
19701 handle unification of a single P/A pair. Parameters are as
19702 for those functions. */
19704 static int
19708 {
19715 /* We can't deduce anything from this, but we might get all the
19716 template args from other function args. */
19719 /* Implicit conversions (Clause 4) will be performed on a function
19720 argument to convert it to the type of the corresponding function
19721 parameter if the parameter type contains no template-parameters that
19722 participate in template argument deduction. */
19725 /* For function parameters with no deducible template parameters,
19726 just return. We'll check non-dependent conversions later. */
19730 {
19732 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19733 | UNIFY_ALLOW_MORE_CV_QUAL
19747 }
19749 /* We only do these transformations if this is the top-level
19750 parameter_type_list in a call or declaration matching; in other
19751 situations (nested function declarators, template argument lists) we
19752 won't be comparing a type to an expression, and we don't do any type
19753 adjustments. */
19755 {
19757 {
19760 {
19761 /* [temp.deduct.type] A template-argument can be
19762 deduced from a pointer to function or pointer
19763 to member function argument if the set of
19764 overloaded functions does not contain function
19765 templates and at most one of a set of
19766 overloaded functions provides a unique
19767 match. */
19771 /* If a unique match was not found, this is a
19772 non-deduced context, so we still succeed. */
19774 }
19780 }
19782 arg_strict |=
19784 }
19785 else
19790 /* For deduction from an init-list we need the actual list. */
19794 }
19796 /* for_each_template_parm callback that always returns 0. */
19798 static int
19800 {
19802 }
19804 /* for_each_template_parm any_fn callback to handle deduction of a template
19805 type argument from the type of an array bound. */
19807 static int
19809 {
19817 {
19823 }
19825 /* Keep walking. */
19827 }
19829 /* Try to deduce any not-yet-deduced template type arguments from the type of
19830 an array bound. This is handled separately from unify because 14.8.2.5 says
19831 "The type of a type parameter is only deduced from an array bound if it is
19832 not otherwise deduced." */
19834 static void
19836 {
19841 }
19843 /* Most parms like fn_type_unification.
19845 If SUBR is 1, we're being called recursively (to unify the
19846 arguments of a function or method parameter of a function
19847 template).
19849 CHECKS is a pointer to a vector of access checks encountered while
19850 substituting default template arguments. */
19852 static int
19854 tree full_targs,
19855 tree xparms,
19859 unification_kind_t strict,
19863 {
19868 tree parms;
19879 /* Reset the number of non-defaulted template arguments contained
19880 in TARGS. */
19883 again:
19891 {
19896 /* For a function parameter pack that occurs at the end of the
19897 parameter-declaration-list, the type A of each remaining
19898 argument of the call is compared with the type P of the
19899 declarator-id of the function parameter pack. */
19905 /* For a function parameter pack that does not occur at the
19906 end of the parameter-declaration-list, the type of the
19907 parameter pack is a non-deduced context. */
19914 explain_p))
19916 }
19921 {
19922 /* Unify the remaining arguments with the pack expansion type. */
19923 tree argvec;
19926 /* Allocate a TREE_VEC and copy in all of the arguments */
19931 /* Copy the parameter into parmvec. */
19937 /* Advance to the end of the list of parameters. */
19939 }
19941 /* Fail if we've reached the end of the parm list, and more args
19942 are present, and the parm list isn't variadic. */
19945 /* Fail if parms are left and they don't have default values and
19946 they aren't all deduced as empty packs (c++/57397). This is
19947 consistent with sufficient_parms_p. */
19950 {
19954 do
19955 {
19958 count++;
19960 }
19964 type_pack_p);
19965 }
19968 {
19969 tsubst_flags_t complain = (explain_p
19970 ? tf_warning_or_error
19975 {
19979 /* Clear the "incomplete" flags on all argument packs now so that
19980 substituting them into later default arguments works. */
19982 {
19985 }
19993 {
19998 }
20000 /* If this is an undeduced nontype parameter that depends on
20001 a type parameter, try another pass; its type may have been
20002 deduced from a later argument than the one from which
20003 this parameter can be deduced. */
20007 {
20010 }
20012 /* Core issue #226 (C++0x) [temp.deduct]:
20014 If a template argument has not been deduced, its
20015 default template argument, if any, is used.
20017 When we are in C++98 mode, TREE_PURPOSE will either
20018 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20019 to explicitly check cxx_dialect here. */
20021 /* OK, there is a default argument. Wait until after the
20022 conversion check to do substitution. */
20025 /* If the type parameter is a parameter pack, then it will
20026 be deduced to an empty parameter pack. */
20028 {
20029 tree arg;
20032 {
20035 }
20036 else
20043 }
20046 }
20048 /* DR 1391: All parameters have args, now check non-dependent parms for
20049 convertibility. */
20053 {
20059 /* For a function parameter pack that occurs at the end of the
20060 parameter-declaration-list, the type A of each remaining
20061 argument of the call is compared with the type P of the
20062 declarator-id of the function parameter pack. */
20068 /* For a function parameter pack that does not occur at the
20069 end of the parameter-declaration-list, the type of the
20070 parameter pack is a non-deduced context. */
20079 explain_p))
20081 }
20083 /* Now substitute into the default template arguments. */
20085 {
20103 {
20104 /* The type of this non-type parameter depends on undeduced
20105 parameters. Don't try to use its default argument yet,
20106 but do check whether the arguments we already have cause
20107 substitution failure, so that that happens before we try
20108 later default arguments (78489). */
20110 NULL_TREE);
20113 else
20115 }
20116 else
20117 {
20125 else
20127 }
20138 {
20140 /* The position of the first default template argument,
20141 is also the number of non-defaulted arguments in TARGS.
20142 Record that. */
20145 }
20146 }
20150 }
20156 }
20158 /* Subroutine of type_unification_real. Args are like the variables
20159 at the call site. ARG is an overloaded function (or template-id);
20160 we try deducing template args from each of the overloads, and if
20161 only one succeeds, we go with that. Modifies TARGS and returns
20162 true on success. */
20164 static bool
20166 tree targs,
20167 tree parm,
20168 tree arg,
20169 unification_kind_t strict,
20172 {
20179 {
20182 }
20183 else
20187 /* Handle `&x' where `x' is some static or non-static member
20188 function name. */
20194 /* Strip baselink information. */
20199 {
20200 /* If we got some explicit template args, we need to plug them into
20201 the affected templates before we try to unify, in case the
20202 explicit args will completely resolve the templates in question. */
20209 {
20222 {
20227 {
20230 }
20231 }
20234 }
20235 /* If no templates (or more than one) are fully resolved by the
20236 explicit arguments, this template-id is a non-deduced context; it
20237 could still be OK if we deduce all template arguments for the
20238 enclosing call through other arguments. */
20241 }
20244 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20245 -- but the deduction does not succeed because the expression is
20246 not just the function on its own. */
20248 else
20250 {
20255 {
20258 }
20259 }
20261 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20262 to function or pointer to member function argument if the set of
20263 overloaded functions does not contain function templates and at most
20264 one of a set of overloaded functions provides a unique match.
20266 So if we found multiple possibilities, we return success but don't
20267 deduce anything. */
20270 {
20274 {
20279 /* Don't forget explicit template arguments in a pack. */
20283 }
20284 }
20289 }
20291 /* Core DR 115: In contexts where deduction is done and fails, or in
20292 contexts where deduction is not done, if a template argument list is
20293 specified and it, along with any default template arguments, identifies
20294 a single function template specialization, then the template-id is an
20295 lvalue for the function template specialization. */
20297 tree
20299 {
20312 {
20315 }
20317 {
20320 }
20322 {
20325 }
20328 {
20332 /* If we got some explicit template args, we need to plug them into
20333 the affected templates before we try to unify, in case the
20334 explicit args will completely resolve the templates in question. */
20342 {
20355 {
20358 {
20361 }
20363 {
20366 }
20367 }
20368 }
20370 {
20378 {
20379 tree base
20382 }
20386 }
20388 /* There were no good options and at least one bad one, so let the
20389 user know what the problem is. */
20391 }
20393 }
20395 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20396 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20397 different overloads deduce different arguments for a given parm.
20398 ADDR_P is true if the expression for which deduction is being
20399 performed was of the form "& fn" rather than simply "fn".
20401 Returns 1 on success. */
20403 static int
20405 tree orig_targs,
20406 tree targs,
20407 tree parm,
20408 tree arg,
20409 unification_kind_t strict,
20413 {
20415 tree tempargs;
20421 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20422 to function or pointer to member function argument if the set of
20423 overloaded functions does not contain function templates and at most
20424 one of a set of overloaded functions provides a unique match.
20426 So if this is a template, just return success. */
20438 /* We don't copy orig_targs for this because if we have already deduced
20439 some template args from previous args, unify would complain when we
20440 try to deduce a template parameter for the same argument, even though
20441 there isn't really a conflict. */
20448 /* First make sure we didn't deduce anything that conflicts with
20449 explicitly specified args. */
20451 {
20458 /* Since we're unifying against ourselves, we will fill in
20459 template args used in the function parm list with our own
20460 template parms. Discard them. */
20463 {
20464 /* Check that the argument at each index of the deduced argument pack
20465 is equivalent to the corresponding explicitly specified argument.
20466 We may have deduced more arguments than were explicitly specified,
20467 and that's OK. */
20469 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20470 that's wrong if we deduce the same argument pack from multiple
20471 function arguments: it's only incomplete the first time. */
20484 }
20487 }
20490 {
20495 }
20498 }
20500 /* PARM is a template class (perhaps with unbound template
20501 parameters). ARG is a fully instantiated type. If ARG can be
20502 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20503 TARGS are as for unify. */
20505 static tree
20508 {
20509 tree copy_of_targs;
20519 /* We need to make a new template argument vector for the call to
20520 unify. If we used TARGS, we'd clutter it up with the result of
20521 the attempted unification, even if this class didn't work out.
20522 We also don't want to commit ourselves to all the unifications
20523 we've already done, since unification is supposed to be done on
20524 an argument-by-argument basis. In other words, consider the
20525 following pathological case:
20527 template <int I, int J, int K>
20528 struct S {};
20530 template <int I, int J>
20531 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20533 template <int I, int J, int K>
20534 void f(S<I, J, K>, S<I, I, I>);
20536 void g() {
20537 S<0, 0, 0> s0;
20538 S<0, 1, 2> s2;
20540 f(s0, s2);
20541 }
20543 Now, by the time we consider the unification involving `s2', we
20544 already know that we must have `f<0, 0, 0>'. But, even though
20545 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20546 because there are two ways to unify base classes of S<0, 1, 2>
20547 with S<I, I, I>. If we kept the already deduced knowledge, we
20548 would reject the possibility I=1. */
20552 {
20556 }
20558 /* If unification failed, we're done. */
20564 }
20566 /* Given a template type PARM and a class type ARG, find the unique
20567 base type in ARG that is an instance of PARM. We do not examine
20568 ARG itself; only its base-classes. If there is not exactly one
20569 appropriate base class, return NULL_TREE. PARM may be the type of
20570 a partial specialization, as well as a plain template type. Used
20571 by unify. */
20573 static enum template_base_result
20576 {
20578 tree binfo;
20584 {
20585 /* The type could not be completed. */
20588 }
20590 /* Walk in inheritance graph order. The search order is not
20591 important, and this avoids multiple walks of virtual bases. */
20593 {
20598 {
20599 /* If there is more than one satisfactory baseclass, then:
20601 [temp.deduct.call]
20603 If they yield more than one possible deduced A, the type
20604 deduction fails.
20606 applies. */
20608 {
20611 }
20614 }
20615 }
20619 }
20621 /* Returns the level of DECL, which declares a template parameter. */
20623 static int
20625 {
20627 {
20637 }
20639 }
20641 /* Decide whether ARG can be unified with PARM, considering only the
20642 cv-qualifiers of each type, given STRICT as documented for unify.
20643 Returns nonzero iff the unification is OK on that basis. */
20645 static int
20647 {
20653 {
20654 /* Although a CVR qualifier is ignored when being applied to a
20655 substituted template parameter ([8.3.2]/1 for example), that
20656 does not allow us to unify "const T" with "int&" because both
20657 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20658 It is ok when we're allowing additional CV qualifiers
20659 at the outer level [14.8.2.1]/3,1st bullet. */
20669 }
20680 }
20682 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20683 void
20685 {
20689 {
20692 }
20693 else
20694 {
20697 }
20698 }
20700 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20701 do { \
20702 if (unify (TP, TA, P, A, S, EP)) \
20703 return 1; \
20704 } while (0)
20706 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20707 expansion at the end of PACKED_PARMS. Returns 0 if the type
20708 deduction succeeds, 1 otherwise. STRICT is the same as in
20709 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20710 function call argument list. We'll need to adjust the arguments to make them
20711 types. SUBR tells us if this is from a recursive call to
20712 type_unification_real, or for comparing two template argument
20713 lists. */
20715 static int
20719 {
20720 tree parm
20726 /* Add in any args remembered from an earlier partial instantiation. */
20734 /* Determine the parameter packs we will be deducing from the
20735 pattern, and record their current deductions. */
20738 {
20742 /* Only template parameter packs can be deduced, not e.g. function
20743 parameter packs or __bases or __integer_pack. */
20747 /* Determine the index and level of this parameter pack. */
20752 /* Keep track of the parameter packs and their corresponding
20753 argument packs. */
20756 }
20758 /* Loop through all of the arguments that have not yet been
20759 unified and unify each with the pattern. */
20761 {
20762 tree parm;
20766 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20767 or the element of its argument pack at the current index if
20768 this argument was explicitly specified. */
20770 {
20779 {
20782 }
20784 }
20786 /* If we had explicit template arguments, substitute them into the
20787 pattern before deduction. */
20789 {
20790 /* Some arguments might still be unspecified or dependent. */
20798 NULL_TREE);
20803 }
20804 else
20807 /* Unify the pattern with the current argument. */
20809 explain_p))
20812 /* For each parameter pack, collect the deduced value. */
20814 {
20820 }
20821 }
20823 /* Verify that the results of unification with the parameter packs
20824 produce results consistent with what we've seen before, and make
20825 the deduced argument packs available. */
20827 {
20834 /* By default keep the original deduced argument pack.
20835 If necessary, more specific code is going to update the
20836 resulting deduced argument later down in this function. */
20840 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20841 actually deduce anything. */
20849 {
20850 /* If we had fewer function args than explicit template args,
20851 just use the explicits. */
20856 }
20859 {
20860 tree result;
20861 /* Build the deduced *_ARGUMENT_PACK. */
20863 {
20866 }
20867 else
20872 /* Note the deduced argument packs for this parameter
20873 pack. */
20875 }
20879 {
20880 /* We only had the explicitly-provided arguments before, but
20881 now we have a complete set of arguments. */
20887 }
20888 else
20889 {
20895 /* Inconsistent unification of this parameter pack. */
20897 bad_old_arg,
20898 bad_new_arg);
20899 }
20900 }
20903 }
20905 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20906 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20907 parameters and return value are as for unify. */
20909 static int
20913 {
20914 tree parm_max;
20915 tree arg_max;
20919 /* Our representation of array types uses "N - 1" as the
20920 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20921 not an integer constant. We cannot unify arbitrarily
20922 complex expressions, so we eliminate the MINUS_EXPRs
20923 here. */
20927 {
20930 }
20934 {
20935 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20936 trying to unify the type of a variable with the type
20937 of a template parameter. For example:
20939 template <unsigned int N>
20940 void f (char (&) [N]);
20941 int g();
20942 void h(int i) {
20943 char a[g(i)];
20944 f(a);
20945 }
20947 Here, the type of the ARG will be "int [g(i)]", and
20948 may be a SAVE_EXPR, etc. */
20952 }
20954 /* If only one of the bounds used a MINUS_EXPR, compensate
20955 by adding one to the other bound. */
20958 integer_type_node,
20959 parm_max,
20960 integer_one_node);
20963 integer_type_node,
20964 arg_max,
20965 integer_one_node);
20969 }
20971 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20975 static pa_kind_t
20977 {
20986 else
20988 }
20990 /* Deduce the value of template parameters. TPARMS is the (innermost)
20991 set of template parameters to a template. TARGS is the bindings
20992 for those template parameters, as determined thus far; TARGS may
20993 include template arguments for outer levels of template parameters
20994 as well. PARM is a parameter to a template function, or a
20995 subcomponent of that parameter; ARG is the corresponding argument.
20996 This function attempts to match PARM with ARG in a manner
20997 consistent with the existing assignments in TARGS. If more values
20998 are deduced, then TARGS is updated.
21000 Returns 0 if the type deduction succeeds, 1 otherwise. The
21001 parameter STRICT is a bitwise or of the following flags:
21003 UNIFY_ALLOW_NONE:
21004 Require an exact match between PARM and ARG.
21005 UNIFY_ALLOW_MORE_CV_QUAL:
21006 Allow the deduced ARG to be more cv-qualified (by qualification
21007 conversion) than ARG.
21008 UNIFY_ALLOW_LESS_CV_QUAL:
21009 Allow the deduced ARG to be less cv-qualified than ARG.
21010 UNIFY_ALLOW_DERIVED:
21011 Allow the deduced ARG to be a template base class of ARG,
21012 or a pointer to a template base class of the type pointed to by
21013 ARG.
21014 UNIFY_ALLOW_INTEGER:
21015 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21016 case for more information.
21017 UNIFY_ALLOW_OUTER_LEVEL:
21018 This is the outermost level of a deduction. Used to determine validity
21019 of qualification conversions. A valid qualification conversion must
21020 have const qualified pointers leading up to the inner type which
21021 requires additional CV quals, except at the outer level, where const
21022 is not required [conv.qual]. It would be normal to set this flag in
21023 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21024 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21025 This is the outermost level of a deduction, and PARM can be more CV
21026 qualified at this point.
21027 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21028 This is the outermost level of a deduction, and PARM can be less CV
21029 qualified at this point. */
21031 static int
21034 {
21036 tree targ;
21037 tree tparm;
21039 tsubst_flags_t complain = (explain_p
21040 ? tf_warning_or_error
21043 /* I don't think this will do the right thing with respect to types.
21044 But the only case I've seen it in so far has been array bounds, where
21045 signedness is the only information lost, and I think that will be
21046 okay. */
21054 /* We can't deduce anything from this, but we might get all the
21055 template args from other function args. */
21061 /* If PARM uses template parameters, then we can't bail out here,
21062 even if ARG == PARM, since we won't record unifications for the
21063 template parameters. We might need them if we're trying to
21064 figure out which of two things is more specialized. */
21068 /* Handle init lists early, so the rest of the function can assume
21069 we're dealing with a type. */
21071 {
21076 /* Replace T with std::initializer_list<T> for deduction. */
21083 /* We can only deduce from an initializer list argument if the
21084 parameter is std::initializer_list or an array; otherwise this
21085 is a non-deduced context. */
21090 else
21091 {
21093 /* Deduction is defined in terms of a single type, so just punt
21094 on the (bizarre) std::initializer_list<T...>. */
21097 }
21100 {
21107 {
21111 /* It should only be possible to get here for a call. */
21113 elt_strict |= maybe_adjust_types_for_deduction
21116 }
21119 explain_p);
21120 }
21124 {
21125 /* Also deduce from the length of the initializer list. */
21132 }
21134 /* If the std::initializer_list<T> deduction worked, replace the
21135 deduced A with std::initializer_list<A>. */
21137 {
21142 }
21144 }
21146 /* If parm and arg aren't the same kind of thing (template, type, or
21147 expression), fail early. */
21151 /* Immediately reject some pairs that won't unify because of
21152 cv-qualification mismatches. */
21155 /* It is the elements of the array which hold the cv quals of an array
21156 type, and the elements might be template type parms. We'll check
21157 when we recurse. */
21159 /* We check the cv-qualifiers when unifying with template type
21160 parameters below. We want to allow ARG `const T' to unify with
21161 PARM `T' for example, when computing which of two templates
21162 is more specialized, for example. */
21176 {
21180 /* In a type which contains a nested-name-specifier, template
21181 argument values cannot be deduced for template parameters used
21182 within the nested-name-specifier. */
21194 /* The PARM is not one we're trying to unify. Just check
21195 to see if it matches ARG. */
21196 {
21201 else
21203 }
21210 /* Check for mixed types and values. */
21218 {
21221 {
21222 /* First try to match ARG directly. */
21224 explain_p);
21226 {
21227 /* Otherwise, look for a suitable base of ARG, as below. */
21234 }
21235 }
21236 /* ARG must be constructed from a template class or a template
21237 template parameter. */
21242 /* Deduce arguments T, i from TT<T> or TT<i>. */
21248 /* Fall through to deduce template name. */
21249 }
21253 {
21254 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21256 /* Simple cases: Value already set, does match or doesn't. */
21261 }
21262 else
21263 {
21264 /* If PARM is `const T' and ARG is only `int', we don't have
21265 a match unless we are allowing additional qualification.
21266 If ARG is `const int' and PARM is just `T' that's OK;
21267 that binds `const int' to `T'. */
21272 /* Consider the case where ARG is `const volatile int' and
21273 PARM is `const T'. Then, T should be `volatile int'. */
21274 arg = cp_build_qualified_type_real
21279 /* Simple cases: Value already set, does match or doesn't. */
21285 /* Make sure that ARG is not a variable-sized array. (Note
21286 that were talking about variable-sized arrays (like
21287 `int[n]'), rather than arrays of unknown size (like
21288 `int[]').) We'll get very confused by such a type since
21289 the bound of the array is not constant, and therefore
21290 not mangleable. Besides, such types are not allowed in
21291 ISO C++, so we can do as we please here. We do allow
21292 them for 'auto' deduction, since that isn't ABI-exposed. */
21296 /* Strip typedefs as in convert_template_argument. */
21298 }
21300 /* If ARG is a parameter pack or an expansion, we cannot unify
21301 against it unless PARM is also a parameter pack. */
21306 /* If the argument deduction results is a METHOD_TYPE,
21307 then there is a problem.
21308 METHOD_TYPE doesn't map to any real C++ type the result of
21309 the deduction can not be of that type. */
21323 {
21324 /* The PARM is not one we're trying to unify. Just check
21325 to see if it matches ARG. */
21331 }
21337 {
21341 /* We're deducing from an array bound, the type doesn't matter. */
21347 }
21349 /* [temp.deduct.type] If, in the declaration of a function template
21350 with a non-type template-parameter, the non-type
21351 template-parameter is used in an expression in the function
21352 parameter-list and, if the corresponding template-argument is
21353 deduced, the template-argument type shall match the type of the
21354 template-parameter exactly, except that a template-argument
21355 deduced from an array bound may be of any integral type.
21356 The non-type parameter might use already deduced type parameters. */
21359 /* We don't have enough levels of args to do any substitution. This
21361 else
21362 {
21368 {
21372 }
21373 }
21376 /* Template-parameter dependent expression. Just accept it for now.
21377 It will later be processed in convert_template_argument. */
21378 ;
21384 /* Convert the ARG to the type of PARM; the deduced non-type
21385 template argument must exactly match the types of the
21386 corresponding parameter. */
21389 {
21390 /* We haven't deduced the type of this parameter yet. */
21392 /* We deduce from array bounds in try_array_deduction. */
21394 {
21395 /* Deduce it from the non-type argument. */
21400 }
21401 else
21402 /* Try again later. */
21404 }
21405 else
21408 /* If ARG is a parameter pack or an expansion, we cannot unify
21409 against it unless PARM is also a parameter pack. */
21414 {
21417 }
21422 {
21423 /* A pointer-to-member constant can be unified only with
21424 another constant. */
21428 /* Just unify the class member. It would be useless (and possibly
21429 wrong, depending on the strict flags) to unify also
21430 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21431 arg refer to the same variable, even if through different
21432 classes. For instance:
21434 struct A { int x; };
21435 struct B : A { };
21437 Unification of &A::x and &B::x must succeed. */
21440 }
21443 {
21447 /* [temp.deduct.call]
21449 A can be another pointer or pointer to member type that can
21450 be converted to the deduced A via a qualification
21451 conversion (_conv.qual_).
21453 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21454 This will allow for additional cv-qualification of the
21455 pointed-to types if appropriate. */
21458 /* The derived-to-base conversion only persists through one
21459 level of pointers. */
21464 }
21496 /* We have already checked cv-qualification at the top of the
21497 function. */
21501 /* As far as unification is concerned, this wins. Later checks
21502 will invalidate it if necessary. */
21505 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21506 /* Type INTEGER_CST can come from ordinary constant template args. */
21518 {
21528 /* Check for pack expansions in the parameters. */
21530 {
21532 {
21534 /* We can unify against something with a trailing
21535 parameter pack. */
21537 else
21538 /* [temp.deduct.type]/9: If the template argument list of
21539 P contains a pack expansion that is not the last
21540 template argument, the entire template argument list
21541 is a non-deduced context. */
21543 }
21544 }
21546 /* If we don't have enough arguments to satisfy the parameters
21547 (not counting the pack expression at the end), or we have
21548 too many arguments for a parameter list that doesn't end in
21549 a pack expression, we can't unify. */
21555 /* Unify all of the parameters that precede the (optional)
21556 pack expression. */
21558 {
21563 }
21566 DEDUCE_EXACT,
21569 }
21577 {
21585 }
21590 {
21594 {
21595 /* First, we try to unify the PARM and ARG directly. */
21600 {
21601 /* Fallback to the special case allowed in
21602 [temp.deduct.call]:
21604 If P is a class, and P has the form
21605 template-id, then A can be a derived class of
21606 the deduced A. Likewise, if P is a pointer to
21607 a class of the form template-id, A can be a
21608 pointer to a derived class pointed to by the
21609 deduced A. */
21615 {
21616 /* Don't give the derived diagnostic if we're
21617 already dealing with the same template. */
21618 bool same_template
21624 }
21625 }
21626 }
21630 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21631 Then, we should unify `int' and `U'. */
21633 else
21634 /* There's no chance of unification succeeding. */
21639 }
21646 {
21649 tree a;
21655 /* CV qualifications for methods can never be deduced, they must
21656 match exactly. We need to check them explicitly here,
21657 because type_unification_real treats them as any other
21658 cv-qualified parameter. */
21660 && (!check_cv_quals_for_unify
21688 {
21700 }
21703 }
21706 /* Unify a pointer to member with a pointer to member function, which
21707 deduces the type of the member as a function type. */
21709 {
21710 /* Check top-level cv qualifiers */
21718 /* Determine the type of the function we are unifying against. */
21722 }
21741 /* Matched cases are handled by the ARG == PARM test above. */
21745 /* We might get a variable as a non-type template argument in parm if the
21746 corresponding parameter is type-dependent. Make any necessary
21747 adjustments based on whether arg is a reference. */
21751 {
21756 }
21757 /* Now use the normal expression code to check whether they match. */
21768 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21769 or UNDERLYING_TYPE nodes. */
21773 /* Unification fails if we hit an error node. */
21778 {
21788 }
21789 /* FALLTHRU */
21792 /* An unresolved overload is a nondeduced context. */
21796 expr:
21797 /* We must be looking at an expression. This can happen with
21798 something like:
21800 template <int I>
21801 void foo(S<I>, S<I + 2>);
21803 This is a "nondeduced context":
21805 [deduct.type]
21807 The nondeduced contexts are:
21809 --A type that is a template-id in which one or more of
21810 the template-arguments is an expression that references
21811 a template-parameter.
21813 In these cases, we assume deduction succeeded, but don't
21814 actually infer any unifications. */
21819 else
21821 }
21822 }
21823 #undef RECUR_AND_CHECK_FAILURE
21824 \f
21825 /* Note that DECL can be defined in this translation unit, if
21826 required. */
21828 static void
21830 {
21831 tree clone;
21835 }
21837 /* Called if RESULT is explicitly instantiated, or is a member of an
21838 explicitly instantiated class. */
21840 void
21842 {
21845 /* If this entity has already been written out, it's too late to
21846 make any modifications. */
21850 /* For anonymous namespace we don't need to do anything. */
21852 {
21855 }
21858 /* The TREE_PUBLIC flag for function declarations will have been
21859 set correctly by tsubst. */
21862 /* This might have been set by an earlier implicit instantiation. */
21867 else
21868 {
21871 /* Always make artificials weak. */
21874 /* For WIN32 we also want to put explicit instantiations in
21875 linkonce sections. */
21878 }
21880 /* If EXTERN_P, then this function will not be emitted -- unless
21881 followed by an explicit instantiation, at which point its linkage
21882 will be adjusted. If !EXTERN_P, then this function will be
21883 emitted here. In neither circumstance do we want
21884 import_export_decl to adjust the linkage. */
21886 }
21888 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21889 important template arguments. If any are missing, we check whether
21890 they're important by using error_mark_node for substituting into any
21891 args that were used for partial ordering (the ones between ARGS and END)
21892 and seeing if it bubbles up. */
21894 static bool
21896 {
21901 {
21904 }
21906 {
21910 }
21912 }
21914 /* Given two function templates PAT1 and PAT2, return:
21916 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21917 -1 if PAT2 is more specialized than PAT1.
21918 0 if neither is more specialized.
21920 LEN indicates the number of parameters we should consider
21921 (defaulted parameters should not be considered).
21923 The 1998 std underspecified function template partial ordering, and
21924 DR214 addresses the issue. We take pairs of arguments, one from
21925 each of the templates, and deduce them against each other. One of
21926 the templates will be more specialized if all the *other*
21927 template's arguments deduce against its arguments and at least one
21928 of its arguments *does* *not* deduce against the other template's
21929 corresponding argument. Deduction is done as for class templates.
21930 The arguments used in deduction have reference and top level cv
21931 qualifiers removed. Iff both arguments were originally reference
21932 types *and* deduction succeeds in both directions, an lvalue reference
21933 wins against an rvalue reference and otherwise the template
21934 with the more cv-qualified argument wins for that pairing (if
21935 neither is more cv-qualified, they both are equal). Unlike regular
21936 deduction, after all the arguments have been deduced in this way,
21937 we do *not* verify the deduced template argument values can be
21938 substituted into non-deduced contexts.
21940 The logic can be a bit confusing here, because we look at deduce1 and
21941 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21942 can find template arguments for pat1 to make arg1 look like arg2, that
21943 means that arg2 is at least as specialized as arg1. */
21945 int
21947 {
21960 /* Remove the this parameter from non-static member functions. If
21961 one is a non-static member function and the other is not a static
21962 member function, remove the first parameter from that function
21963 also. This situation occurs for operator functions where we
21964 locate both a member function (with this pointer) and non-member
21965 operator (with explicit first operand). */
21967 {
21972 }
21974 {
21977 {
21978 len--;
21980 }
21981 }
21983 /* If only one is a conversion operator, they are unordered. */
21987 /* Consider the return type for a conversion function */
21989 {
21992 len++;
21993 }
21995 processing_template_decl++;
22001 /* Stop when an ellipsis is seen. */
22003 {
22014 {
22015 /* When both arguments are pack expansions, we need only
22016 unify the patterns themselves. */
22020 /* This is the last comparison we need to do. */
22022 }
22024 /* DR 1847: If a particular P contains no template-parameters that
22025 participate in template argument deduction, that P is not used to
22026 determine the ordering. */
22032 {
22036 }
22039 {
22043 }
22049 {
22055 /* Setup the parameter vector, which contains only ARG1. */
22058 /* Setup the argument vector, which contains the remaining
22059 arguments. */
22068 /* We cannot deduce in the other direction, because ARG1 is
22069 a pack expansion but ARG2 is not. */
22071 }
22073 {
22079 /* Setup the parameter vector, which contains only ARG1. */
22082 /* Setup the argument vector, which contains the remaining
22083 arguments. */
22092 /* We cannot deduce in the other direction, because ARG2 is
22093 a pack expansion but ARG1 is not.*/
22095 }
22097 else
22098 {
22099 /* The normal case, where neither argument is a pack
22100 expansion. */
22107 }
22109 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22110 arg2, then arg2 is not as specialized as arg1. */
22116 /* "If, for a given type, deduction succeeds in both directions
22117 (i.e., the types are identical after the transformations above)
22118 and both P and A were reference types (before being replaced with
22119 the type referred to above):
22120 - if the type from the argument template was an lvalue reference and
22121 the type from the parameter template was not, the argument type is
22122 considered to be more specialized than the other; otherwise,
22123 - if the type from the argument template is more cv-qualified
22124 than the type from the parameter template (as described above),
22125 the argument type is considered to be more specialized than the other;
22126 otherwise,
22127 - neither type is more specialized than the other." */
22130 {
22132 {
22135 else
22137 }
22139 {
22144 }
22145 }
22148 /* We've failed to deduce something in either direction.
22149 These must be unordered. */
22152 next:
22156 /* We have already processed all of the arguments in our
22157 handing of the pack expansion type. */
22162 }
22164 /* "In most cases, all template parameters must have values in order for
22165 deduction to succeed, but for partial ordering purposes a template
22166 parameter may remain without a value provided it is not used in the
22167 types being used for partial ordering."
22169 Thus, if we are missing any of the targs1 we need to substitute into
22170 origs1, then pat2 is not as specialized as pat1. This can happen when
22171 there is a nondeduced context. */
22177 processing_template_decl--;
22179 /* If both deductions succeed, the partial ordering selects the more
22180 constrained template. */
22182 {
22187 }
22189 /* All things being equal, if the next argument is a pack expansion
22190 for one function but not for the other, prefer the
22191 non-variadic function. FIXME this is bogus; see c++/41958. */
22195 {
22198 }
22204 else
22206 }
22208 /* Determine which of two partial specializations of TMPL is more
22209 specialized.
22211 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22212 to the first partial specialization. The TREE_PURPOSE is the
22213 innermost set of template parameters for the partial
22214 specialization. PAT2 is similar, but for the second template.
22216 Return 1 if the first partial specialization is more specialized;
22217 -1 if the second is more specialized; 0 if neither is more
22218 specialized.
22220 See [temp.class.order] for information about determining which of
22221 two templates is more specialized. */
22223 static int
22225 {
22226 tree targs;
22235 /* Just like what happens for functions, if we are ordering between
22236 different template specializations, we may encounter dependent
22237 types in the arguments, and we need our dependency check functions
22238 to behave correctly. */
22242 {
22245 }
22249 {
22252 }
22255 /* If both deductions succeed, the partial ordering selects the more
22256 constrained template. */
22260 /* In the case of a tie where at least one of the templates
22261 has a parameter pack at the end, the template with the most
22262 non-packed parameters wins. */
22264 && any_deductions
22267 {
22273 /* We don't count the pack expansion at the end. */
22283 }
22286 }
22288 /* Return the template arguments that will produce the function signature
22289 DECL from the function template FN, with the explicit template
22290 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22291 also match. Return NULL_TREE if no satisfactory arguments could be
22292 found. */
22294 static tree
22296 {
22300 tree decl_arg_types;
22303 tree arg;
22307 /* Never do unification on the 'this' parameter. */
22328 }
22330 /* Return the innermost template arguments that, when applied to a partial
22331 specialization SPEC_TMPL of TMPL, yield the ARGS.
22333 For example, suppose we have:
22335 template <class T, class U> struct S {};
22336 template <class T> struct S<T*, int> {};
22338 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22339 partial specialization and the ARGS will be {double*, int}. The resulting
22340 vector will be {double}, indicating that `T' is bound to `double'. */
22342 static tree
22344 {
22346 tree spec_args
22349 tree deduced_args;
22350 tree innermost_deduced_args;
22354 {
22358 innermost_deduced_args);
22359 }
22360 else
22364 again:
22373 {
22375 {
22381 }
22383 }
22387 {
22390 }
22392 /* Verify that nondeduced template arguments agree with the type
22393 obtained from argument deduction.
22395 For example:
22397 struct A { typedef int X; };
22398 template <class T, class U> struct C {};
22399 template <class T> struct C<T, typename T::X> {};
22401 Then with the instantiation `C<A, int>', we can deduce that
22402 `T' is `A' but unify () does not check whether `typename T::X'
22403 is `int'. */
22414 /* We only need to check the innermost arguments; the other
22415 arguments will always agree. */
22420 /* Now that we have bindings for all of the template arguments,
22421 ensure that the arguments deduced for the template template
22422 parameters have compatible template parameter lists. See the use
22423 of template_template_parm_bindings_ok_p in fn_type_unification
22424 for more information. */
22429 }
22431 // Compare two function templates T1 and T2 by deducing bindings
22432 // from one against the other. If both deductions succeed, compare
22433 // constraints to see which is more constrained.
22434 static int
22436 {
22441 {
22444 }
22447 {
22450 }
22452 // If both deductions succeed, then one may be more constrained.
22457 }
22459 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22460 Return the TREE_LIST node with the most specialized template, if
22461 any. If there is no most specialized template, the error_mark_node
22462 is returned.
22464 Note that this function does not look at, or modify, the
22465 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22466 returned is one of the elements of INSTANTIATIONS, callers may
22467 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22468 and retrieve it from the value returned. */
22470 tree
22472 {
22479 {
22485 {
22486 /* Equally specialized, move to next function. If there
22487 is no next function, nothing's most specialized. */
22492 }
22493 }
22496 /* Now verify that champ is better than everything earlier in the
22497 instantiation list. */
22500 {
22503 }
22504 }
22506 processing_template_decl--;
22512 }
22514 /* If DECL is a specialization of some template, return the most
22515 general such template. Otherwise, returns NULL_TREE.
22517 For example, given:
22519 template <class T> struct S { template <class U> void f(U); };
22521 if TMPL is `template <class U> void S<int>::f(U)' this will return
22522 the full template. This function will not trace past partial
22523 specializations, however. For example, given in addition:
22525 template <class T> struct S<T*> { template <class U> void f(U); };
22527 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22528 `template <class T> template <class U> S<T*>::f(U)'. */
22530 tree
22532 {
22534 {
22537 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22538 template friend, or a FIELD_DECL for a capture pack. */
22541 }
22543 /* Look for more and more general templates. */
22545 {
22546 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22547 (See cp-tree.h for details.) */
22556 /* Stop if we run into an explicitly specialized class template. */
22563 }
22566 }
22568 /* Return the most specialized of the template partial specializations
22569 which can produce TARGET, a specialization of some class or variable
22570 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22571 a TEMPLATE_DECL node corresponding to the partial specialization, while
22572 the TREE_PURPOSE is the set of template arguments that must be
22573 substituted into the template pattern in order to generate TARGET.
22575 If the choice of partial specialization is ambiguous, a diagnostic
22576 is issued, and the error_mark_node is returned. If there are no
22577 partial specializations matching TARGET, then NULL_TREE is
22578 returned, indicating that the primary template should be used. */
22580 static tree
22582 {
22584 tree t;
22585 tree champ;
22592 {
22596 }
22598 {
22601 }
22603 {
22607 }
22608 else
22613 /* For determining which partial specialization to use, only the
22614 innermost args are interesting. */
22616 {
22619 }
22622 {
22623 tree spec_args;
22627 {
22628 /* Substitute in the template args from the enclosing class. */
22632 }
22639 {
22643 /* Keep the candidate only if the constraints are satisfied,
22644 or if we're not compiling with concepts. */
22647 {
22650 }
22651 }
22652 }
22662 {
22665 ;
22666 else
22667 {
22669 {
22672 {
22675 }
22676 }
22678 }
22679 }
22683 {
22686 {
22689 }
22690 }
22693 {
22700 else
22704 {
22709 }
22712 }
22715 }
22717 /* Explicitly instantiate DECL. */
22719 void
22721 {
22726 /* An error occurred, for which grokdeclarator has already issued
22727 an appropriate message. */
22730 {
22733 }
22739 {
22740 /* There is an asymmetry here in the way VAR_DECLs and
22741 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22742 the latter, the DECL we get back will be marked as a
22743 template instantiation, and the appropriate
22744 DECL_TEMPLATE_INFO will be set up. This does not happen for
22745 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22746 should handle VAR_DECLs as it currently handles
22747 FUNCTION_DECLs. */
22749 {
22752 }
22755 {
22758 }
22760 {
22765 }
22766 }
22768 {
22771 }
22772 else
22775 /* Check for various error cases. Note that if the explicit
22776 instantiation is valid the RESULT will currently be marked as an
22777 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22778 until we get here. */
22781 {
22782 /* DR 259 [temp.spec].
22784 Both an explicit instantiation and a declaration of an explicit
22785 specialization shall not appear in a program unless the explicit
22786 instantiation follows a declaration of the explicit specialization.
22788 For a given set of template parameters, if an explicit
22789 instantiation of a template appears after a declaration of an
22790 explicit specialization for that template, the explicit
22791 instantiation has no effect. */
22793 }
22795 {
22796 /* [temp.spec]
22798 No program shall explicitly instantiate any template more
22799 than once.
22801 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22802 the first instantiation was `extern' and the second is not,
22803 and EXTERN_P for the opposite case. */
22806 /* If an "extern" explicit instantiation follows an ordinary
22807 explicit instantiation, the template is instantiated. */
22810 }
22812 {
22815 }
22817 {
22820 }
22823 ;
22825 {
22828 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22831 }
22832 else
22840 }
22842 static void
22844 {
22850 {
22853 }
22854 }
22856 /* Called from do_type_instantiation through binding_table_foreach to
22857 do recursive instantiation for the type bound in ENTRY. */
22858 static void
22860 {
22867 }
22869 /* Perform an explicit instantiation of template class T. STORAGE, if
22870 non-null, is the RID for extern, inline or static. COMPLAIN is
22871 nonzero if this is called from the parser, zero if called recursively,
22872 since the standard is unclear (as detailed below). */
22874 void
22876 {
22886 {
22887 tree tmpl =
22891 else
22894 }
22899 {
22902 t);
22904 }
22907 {
22909 {
22911 {
22914 "ISO C++ 1998 forbids the use of %<extern%> on "
22916 }
22917 else
22919 "ISO C++ forbids the use of %qE"
22921 }
22929 else
22930 {
22932 storage);
22934 }
22935 }
22938 {
22939 /* DR 259 [temp.spec].
22941 Both an explicit instantiation and a declaration of an explicit
22942 specialization shall not appear in a program unless the explicit
22943 instantiation follows a declaration of the explicit specialization.
22945 For a given set of template parameters, if an explicit
22946 instantiation of a template appears after a declaration of an
22947 explicit specialization for that template, the explicit
22948 instantiation has no effect. */
22950 }
22952 {
22953 /* [temp.spec]
22955 No program shall explicitly instantiate any template more
22956 than once.
22958 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22959 instantiation was `extern'. If EXTERN_P then the second is.
22960 These cases are OK. */
22967 /* If we've already instantiated the template, just return now. */
22970 }
22978 /* In contrast to implicit instantiation, where only the
22979 declarations, and not the definitions, of members are
22980 instantiated, we have here:
22982 [temp.explicit]
22984 The explicit instantiation of a class template specialization
22985 implies the instantiation of all of its members not
22986 previously explicitly specialized in the translation unit
22987 containing the explicit instantiation.
22989 Of course, we can't instantiate member template classes, since we
22990 don't have any arguments for them. Note that the standard is
22991 unclear on whether the instantiation of the members are
22992 *explicit* instantiations or not. However, the most natural
22993 interpretation is that it should be an explicit
22994 instantiation. */
22998 && !static_p
23001 {
23006 }
23011 }
23013 /* Given a function DECL, which is a specialization of TMPL, modify
23014 DECL to be a re-instantiation of TMPL with the same template
23015 arguments. TMPL should be the template into which tsubst'ing
23016 should occur for DECL, not the most general template.
23018 One reason for doing this is a scenario like this:
23020 template <class T>
23021 void f(const T&, int i);
23023 void g() { f(3, 7); }
23025 template <class T>
23026 void f(const T& t, const int i) { }
23028 Note that when the template is first instantiated, with
23029 instantiate_template, the resulting DECL will have no name for the
23030 first parameter, and the wrong type for the second. So, when we go
23031 to instantiate the DECL, we regenerate it. */
23033 static void
23035 {
23036 /* The arguments used to instantiate DECL, from the most general
23037 template. */
23038 tree code_pattern;
23042 /* Make sure that we can see identifiers, and compute access
23043 correctly. */
23047 {
23048 tree decl_parm;
23049 tree pattern_parm;
23050 tree specs;
23064 specs);
23066 /* Merge parameter declarations. */
23069 pattern_parm
23073 {
23074 tree parm_type;
23075 tree attributes;
23080 NULL_TREE);
23086 {
23089 }
23092 }
23093 /* Merge any parameters that match with the function parameter
23094 pack. */
23096 {
23098 tree expanded_types;
23099 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23100 the parameters in this function parameter pack. */
23105 {
23106 tree parm_type;
23107 tree attributes;
23110 /* Rename the parameter to include the index. */
23119 {
23122 }
23124 }
23125 }
23126 /* Merge additional specifiers from the CODE_PATTERN. */
23130 }
23132 {
23142 }
23143 else
23147 }
23149 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23150 substituted to get DECL. */
23152 tree
23154 {
23157 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23158 for the instantiation. This is not always the most general
23159 template. Consider, for example:
23161 template <class T>
23162 struct S { template <class U> void f();
23163 template <> void f<int>(); };
23165 and an instantiation of S<double>::f<int>. We want TD to be the
23166 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23168 more general template. */
23170 /* We must also deal with friend templates. Given:
23172 template <class T> struct S {
23173 template <class U> friend void f() {};
23174 };
23176 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23177 so far as the language is concerned, but that's still
23178 where we get the pattern for the instantiation from. On
23179 other hand, if the definition comes outside the class, say:
23181 template <class T> struct S {
23182 template <class U> friend void f();
23183 };
23184 template <class U> friend void f() {}
23186 we don't need to look any further. That's what the check for
23187 DECL_INITIAL is for. */
23191 {
23192 /* The present template, TD, should not be a definition. If it
23193 were a definition, we should be using it! Note that we
23194 cannot restructure the loop to just keep going until we find
23195 a template with a definition, since that might go too far if
23196 a specialization was declared, but not defined. */
23198 /* Fetch the more general template. */
23200 }
23203 }
23205 /* Returns true if we need to instantiate this template instance even if we
23206 know we aren't going to emit it. */
23208 bool
23210 {
23211 /* We always instantiate inline functions so that we can inline them. An
23212 explicit instantiation declaration prohibits implicit instantiation of
23213 non-inline functions. With high levels of optimization, we would
23214 normally inline non-inline functions -- but we're not allowed to do
23215 that for "extern template" functions. Therefore, we check
23216 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23220 /* And we need to instantiate static data members so that
23221 their initializers are available in integral constant
23222 expressions. */
23225 }
23227 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23228 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23229 error, true otherwise. */
23231 bool
23233 {
23236 /* Don't instantiate a noexcept-specification from template context. */
23251 {
23257 {
23258 /* If hash_set::add returns true, the element was already there. */
23263 fn);
23265 }
23267 {
23282 }
23283 else
23293 }
23296 {
23299 else
23301 }
23304 }
23306 /* We're starting to process the function INST, an instantiation of PATTERN;
23307 add their parameters to local_specializations. */
23309 static void
23311 {
23315 {
23319 }
23321 {
23323 {
23326 }
23327 else
23328 {
23329 /* Register the (value) argument pack as a specialization of
23330 TMPL_PARM, then move on. */
23333 }
23334 }
23336 }
23338 /* Produce the definition of D, a _DECL generated from a template. If
23339 DEFER_OK is true, then we don't have to actually do the
23340 instantiation now; we just have to do it sometime. Normally it is
23341 an error if this is an explicit instantiation but D is undefined.
23342 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23343 instantiated class template. */
23345 tree
23347 {
23349 tree gen_args;
23350 tree args;
23351 tree td;
23352 tree code_pattern;
23353 tree spec;
23354 tree gen_tmpl;
23362 /* This function should only be used to instantiate templates for
23363 functions and static member variables. */
23366 /* A concept is never instantiated. */
23369 /* Variables are never deferred; if instantiation is required, they
23370 are instantiated right away. That allows for better code in the
23371 case that an expression refers to the value of the variable --
23372 if the variable has a constant value the referring expression can
23373 take advantage of that fact. */
23377 /* Don't instantiate cloned functions. Instead, instantiate the
23378 functions they cloned. */
23386 /* D has already been instantiated or explicitly specialized, so
23387 there's nothing for us to do here.
23389 It might seem reasonable to check whether or not D is an explicit
23390 instantiation, and, if so, stop here. But when an explicit
23391 instantiation is deferred until the end of the compilation,
23392 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23393 the instantiation. */
23396 /* Check to see whether we know that this template will be
23397 instantiated in some other file, as with "extern template"
23398 extension. */
23401 /* In general, we do not instantiate such templates. */
23409 /* We should already have the extra args. */
23412 /* And what's in the hash table should match D. */
23416 /* This needs to happen before any tsubsting. */
23422 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23423 for the instantiation. */
23428 {
23429 /* Look up an explicit specialization, if any. */
23433 {
23436 }
23437 }
23441 /* We should never be trying to instantiate a member of a class
23442 template or partial specialization. */
23447 /* In the case of a friend template whose definition is provided
23448 outside the class, we may have too many arguments. Drop the
23449 ones we don't need. The same is true for specializations. */
23450 args = get_innermost_template_args
23454 {
23460 }
23461 else
23462 {
23467 else
23469 }
23471 /* We may be in the middle of deferred access check. Disable it now. */
23474 /* Unless an explicit instantiation directive has already determined
23475 the linkage of D, remember that a definition is available for
23476 this entity. */
23486 /* If D is a member of an explicitly instantiated class template,
23487 and no definition is available, treat it like an implicit
23488 instantiation. */
23491 {
23492 /* Leave linkage flags alone on instantiations with anonymous
23493 visibility. */
23495 {
23498 }
23500 }
23502 /* Defer all other templates, unless we have been explicitly
23503 forbidden from doing so. */
23505 template. */
23506 ! pattern_defined
23507 /* If it's OK to postpone instantiation, do so. */
23508 || defer_ok
23509 /* If this is a static data member that will be defined
23510 elsewhere, we don't want to instantiate the entire data
23511 member, but we do want to instantiate the initializer so that
23512 we can substitute that elsewhere. */
23514 /* Handle here a deleted function too, avoid generating
23515 its body (c++/61080). */
23517 {
23518 /* The definition of the static data member is now required so
23519 we must substitute the initializer. */
23523 {
23524 tree ns;
23525 tree init;
23534 args,
23537 /* If instantiating the initializer involved instantiating this
23538 again, don't call cp_finish_decl twice. */
23540 {
23541 /* Make sure the initializer is still constant, in case of
23542 circular dependency (template/instantiate6.C). */
23543 const_init
23547 LOOKUP_ONLYCONVERTING);
23548 }
23552 }
23554 /* We restore the source position here because it's used by
23555 add_pending_template. */
23561 /* [temp.explicit]
23563 The definition of a non-exported function template, a
23564 non-exported member function template, or a non-exported
23565 member function or static data member of a class template
23566 shall be present in every translation unit in which it is
23567 explicitly instantiated. */
23571 /* If we're in unevaluated context, we just wanted to get the
23572 constant value; this isn't an odr use, so don't queue
23573 a full instantiation. */
23576 /* ??? Historically, we have instantiated inline functions, even
23577 when marked as "extern template". */
23581 }
23582 /* Tell the repository that D is available in this translation unit
23583 -- and see if it is supposed to be instantiated here. */
23585 {
23586 /* In a PCH file, despite the fact that the repository hasn't
23587 requested instantiation in the PCH it is still possible that
23588 an instantiation will be required in a file that includes the
23589 PCH. */
23592 /* Instantiate inline functions so that the inliner can do its
23593 job, even though we'll not be emitting a copy of this
23594 function. */
23597 }
23600 tree fn_context;
23603 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23614 else
23615 {
23619 }
23621 /* Mark D as instantiated so that recursive calls to
23622 instantiate_decl do not try to instantiate it again. */
23625 /* Regenerate the declaration in case the template has been modified
23626 by a subsequent redeclaration. */
23629 /* We already set the file and line above. Reset them now in case
23630 they changed as a result of calling regenerate_decl_from_template. */
23634 {
23635 tree init;
23638 /* Clear out DECL_RTL; whatever was there before may not be right
23639 since we've reset the type of the declaration. */
23643 /* The initializer is placed in DECL_INITIAL by
23644 regenerate_decl_from_template so we don't need to
23645 push/pop_access_scope again here. Pull it out so that
23646 cp_finish_decl can process it. */
23651 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23652 initializer. That function will defer actual emission until
23653 we have a chance to determine linkage. */
23656 /* Enter the scope of D so that access-checking works correctly. */
23669 }
23673 {
23674 /* Set up the list of local specializations. */
23678 /* Set up context. */
23682 else
23685 /* Some typedefs referenced from within the template code need to be
23686 access checked at template instantiation time, i.e now. These
23687 types were added to the template at parsing time. Let's get those
23688 and perform the access checks then. */
23690 args);
23692 /* Create substitution entries for the parameters. */
23695 /* Substitute into the body of the function. */
23699 else
23700 {
23705 /* Set the current input_location to the end of the function
23706 so that finish_function knows where we are. */
23707 input_location
23710 /* Remember if we saw an infinite loop in the template. */
23711 current_function_infinite_loop
23713 }
23715 /* Finish the function. */
23719 else
23720 {
23723 }
23727 }
23729 /* We're not deferring instantiation any more. */
23734 else
23740 out:
23749 }
23751 /* Run through the list of templates that we wish we could
23752 instantiate, and instantiate any we can. RETRIES is the
23753 number of times we retry pending template instantiation. */
23755 void
23757 {
23761 /* Instantiating templates may trigger vtable generation. This in turn
23762 may require further template instantiations. We place a limit here
23763 to avoid infinite loop. */
23765 {
23769 "template instantiation depth exceeds maximum of %d"
23770 " instantiating %q+D, possibly from virtual table generation"
23774 /* Pretend that we defined it. */
23777 }
23779 do
23780 {
23785 {
23790 {
23792 {
23807 }
23810 }
23811 else
23812 {
23815 {
23816 instantiation
23822 }
23826 }
23829 /* If INSTANTIATION has been instantiated, then we don't
23830 need to consider it again in the future. */
23832 else
23833 {
23836 }
23839 }
23841 }
23845 }
23847 /* Substitute ARGVEC into T, which is a list of initializers for
23848 either base class or a non-static data member. The TREE_PURPOSEs
23849 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23850 instantiate_decl. */
23852 static tree
23854 {
23859 {
23860 tree decl;
23861 tree init;
23867 {
23868 tree expr;
23869 tree arg;
23871 /* Expand the base class expansion type into separate base
23872 classes. */
23874 tf_warning_or_error,
23875 NULL_TREE);
23879 /* We'll be building separate TREE_LISTs of arguments for
23880 each base. */
23886 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23887 expand each argument in the TREE_VALUE of t. */
23894 /* VOID_TYPE_NODE is used to indicate
23895 value-initialization. */
23896 {
23899 }
23900 else
23901 {
23902 /* Substitute parameter packs into each argument in the
23903 TREE_LIST. */
23906 {
23907 tree expanded_exprs;
23909 /* Expand the argument. */
23911 expanded_exprs
23913 tf_warning_or_error,
23914 NULL_TREE);
23918 /* Prepend each of the expanded expressions to the
23919 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23921 {
23926 }
23927 }
23930 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23931 since we built them backwards. */
23933 {
23936 }
23937 }
23938 }
23941 {
23943 {
23947 }
23948 else
23949 {
23950 tree tmp;
23965 /* If we had an initializer but it instantiated to nothing,
23966 value-initialize the object. This will only occur when
23967 the initializer was a pack expansion where the parameter
23968 packs used in that expansion were of length zero. */
23971 }
23975 {
23977 decl);
23979 }
23980 /* Look for a target constructor. */
23984 {
23987 {
23991 }
23993 }
23996 {
24000 }
24001 }
24002 }
24004 }
24006 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24008 static void
24010 {
24015 else
24017 }
24019 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24020 is the instantiation (which should have been created with
24021 start_enum) and ARGS are the template arguments to use. */
24023 static void
24025 {
24026 tree e;
24032 {
24033 tree value;
24034 tree decl;
24037 /* Note that in a template enum, the TREE_VALUE is the
24038 CONST_DECL, not the corresponding INTEGER_CST. */
24043 /* Give this enumeration constant the correct access. */
24046 /* Actually build the enumerator itself. Here we're assuming that
24047 enumerators can't have dependent attributes. */
24050 }
24060 }
24062 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24063 its type -- but without substituting the innermost set of template
24064 arguments. So, innermost set of template parameters will appear in
24065 the type. */
24067 tree
24069 {
24070 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24072 }
24074 /* Return truthvalue if we're processing a template different from
24075 the last one involved in diagnostics. */
24076 bool
24078 {
24080 }
24082 /* Remember current template involved in diagnostics. */
24083 void
24085 {
24087 }
24091 {
24093 }
24095 /* Return TRUE if current_function_decl is being instantiated, false
24096 otherwise. */
24098 bool
24100 {
24103 }
24105 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24106 type. Return false for ok, true for disallowed. Issue error and
24107 inform messages under control of COMPLAIN. */
24109 static bool
24111 {
24129 /* A bound template template parm could later be instantiated to have a valid
24130 nontype parm type via an alias template. */
24136 {
24139 else
24141 type);
24142 }
24144 }
24146 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24147 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24149 static bool
24151 {
24152 tree scope;
24154 /* [temp.dep.type]
24156 A type is dependent if it is:
24158 -- a template parameter. Template template parameters are types
24159 for us (since TYPE_P holds true for them) so we handle
24160 them here. */
24164 /* -- a qualified-id with a nested-name-specifier which contains a
24165 class-name that names a dependent type or whose unqualified-id
24166 names a dependent type. */
24170 /* An alias template specialization can be dependent even if the
24171 resulting type is not. */
24175 /* -- a cv-qualified type where the cv-unqualified type is
24176 dependent.
24177 No code is necessary for this bullet; the code below handles
24178 cv-qualified types, and we don't want to strip aliases with
24179 TYPE_MAIN_VARIANT because of DR 1558. */
24180 /* -- a compound type constructed from any dependent type. */
24190 {
24191 tree arg_type;
24196 arg_type;
24201 /* A value-dependent noexcept-specifier makes the type dependent. */
24204 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24205 affect overload resolution and treating it as dependent breaks
24206 things. */
24211 }
24212 /* -- an array type constructed from any dependent type or whose
24213 size is specified by a constant expression that is
24214 value-dependent.
24216 We checked for type- and value-dependence of the bounds in
24217 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24219 {
24224 }
24226 /* -- a template-id in which either the template name is a template
24227 parameter ... */
24230 /* ... or any of the template arguments is a dependent type or
24231 an expression that is type-dependent or value-dependent. */
24233 && (any_dependent_template_arguments_p
24237 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24238 dependent; if the argument of the `typeof' expression is not
24239 type-dependent, then it should already been have resolved. */
24245 /* A template argument pack is dependent if any of its packed
24246 arguments are. */
24248 {
24254 }
24256 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24257 be template parameters. */
24264 /* The standard does not specifically mention types that are local
24265 to template functions or local classes, but they should be
24266 considered dependent too. For example:
24268 template <int I> void f() {
24269 enum E { a = I };
24270 S<sizeof (E)> s;
24271 }
24273 The size of `E' cannot be known until the value of `I' has been
24274 determined. Therefore, `E' must be considered dependent. */
24278 /* Don't use type_dependent_expression_p here, as it can lead
24279 to infinite recursion trying to determine whether a lambda
24280 nested in a lambda is dependent (c++/47687). */
24284 && (any_dependent_template_arguments_p
24288 /* Other types are non-dependent. */
24290 }
24292 /* Returns TRUE if TYPE is dependent, in the sense of
24293 [temp.dep.type]. Note that a NULL type is considered dependent. */
24295 bool
24297 {
24298 /* If there are no template parameters in scope, then there can't be
24299 any dependent types. */
24301 {
24302 /* If we are not processing a template, then nobody should be
24303 providing us with a dependent type. */
24307 }
24309 /* If the type is NULL, we have not computed a type for the entity
24310 in question; in that case, the type is dependent. */
24314 /* Erroneous types can be considered non-dependent. */
24318 /* Getting here with global_type_node means we improperly called this
24319 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24322 /* If we have not already computed the appropriate value for TYPE,
24323 do so now. */
24325 {
24328 }
24331 }
24333 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24334 lookup. In other words, a dependent type that is not the current
24335 instantiation. */
24337 bool
24339 {
24342 }
24344 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24345 an unknown base of 'this' (and is therefore instantiation-dependent). */
24347 static bool
24349 {
24366 }
24368 /* T is a SCOPE_REF; return whether we need to consider it
24369 instantiation-dependent so that we can check access at instantiation
24370 time even though we know which member it resolves to. */
24372 static bool
24374 {
24381 else
24383 }
24385 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24386 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24387 expression. */
24389 /* Note that this predicate is not appropriate for general expressions;
24390 only constant expressions (that satisfy potential_constant_expression)
24391 can be tested for value dependence. */
24393 bool
24395 {
24399 /* A type-dependent expression is also value-dependent. */
24404 {
24406 /* A dependent member function of the current instantiation. */
24410 /* A dependent member function of the current instantiation. */
24417 /* A name that has not been looked up -- must be dependent. */
24421 /* A non-type template parm. */
24425 /* A non-type template parm. */
24431 /* A constant with literal type and is initialized
24432 with an expression that is value-dependent. */
24434 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24438 {
24442 }
24451 /* These expressions are value-dependent if the type to which
24452 the cast occurs is dependent or the expression being casted
24453 is value-dependent. */
24454 {
24460 /* A functional cast has a list of operands. */
24463 {
24464 /* If there are no operands, it must be an expression such
24465 as "int()". This should not happen for aggregate types
24466 because it would form non-constant expressions. */
24471 }
24477 }
24482 /* FALLTHRU */
24485 /* A `sizeof' expression is value-dependent if the operand is
24486 type-dependent or is a pack expansion. */
24495 /* An 'encode' expression is value-dependent if the operand is
24496 type-dependent. */
24505 /* All instantiation-dependent expressions should also be considered
24506 value-dependent. */
24514 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24515 is value-dependent. */
24516 {
24525 }
24528 {
24545 }
24556 {
24560 }
24563 /* Treat all requires-expressions as value-dependent so
24564 we don't try to fold them. */
24571 {
24578 {
24580 /* In a call to a constexpr member function, look through the
24581 implicit ADDR_EXPR on the object argument so that it doesn't
24582 cause the call to be considered value-dependent. We also
24583 look through it in potential_constant_expression. */
24590 }
24592 }
24598 {
24600 tree val;
24607 }
24610 /* Treat a GNU statement expression as dependent to avoid crashing
24611 under instantiate_non_dependent_expr; it can't be constant. */
24615 /* A constant expression is value-dependent if any subexpression is
24616 value-dependent. */
24618 {
24625 {
24629 {
24632 /* In some cases, some of the operands may be missing.
24633 (For example, in the case of PREDECREMENT_EXPR, the
24634 amount to increment by may be missing.) That doesn't
24635 make the expression dependent. */
24638 }
24639 }
24643 }
24645 }
24647 /* The expression is not value-dependent. */
24649 }
24651 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24652 [temp.dep.expr]. Note that an expression with no type is
24653 considered dependent. Other parts of the compiler arrange for an
24654 expression with type-dependent subexpressions to have no type, so
24655 this function doesn't have to be fully recursive. */
24657 bool
24659 {
24668 /* An unresolved name is always dependent. */
24674 /* A fold expression is type-dependent. */
24681 /* Some expression forms are never type-dependent. */
24695 /* The types of these expressions depends only on the type to which
24696 the cast occurs. */
24705 /* The types of these expressions depends only on the type created
24706 by the expression. */
24709 {
24710 /* For NEW_EXPR tree nodes created inside a template, either
24711 the object type itself or a TREE_LIST may appear as the
24712 operand 1. */
24715 /* This is an array type. We need to check array dimensions
24716 as well. */
24718 || value_dependent_expression_p
24720 else
24722 }
24725 {
24729 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24730 contains an identifier associated by name lookup with one or more
24731 declarations declared with a dependent type, or...a
24732 nested-name-specifier or qualified-id that names a member of an
24733 unknown specialization. */
24736 }
24746 {
24747 tree elt;
24751 {
24754 }
24756 }
24758 /* A static data member of the current instantiation with incomplete
24759 array type is type-dependent, as the definition and specializations
24760 can have different bounds. */
24767 /* An array of unknown bound depending on a variadic parameter, eg:
24769 template<typename... Args>
24770 void foo (Args... args)
24771 {
24772 int arr[] = { args... };
24773 }
24775 template<int... vals>
24776 void bar ()
24777 {
24778 int arr[] = { vals... };
24779 }
24781 If the array has no length and has an initializer, it must be that
24782 we couldn't determine its length in cp_complete_array_type because
24783 it is dependent. */
24791 /* A function or variable template-id is type-dependent if it has any
24792 dependent template arguments. */
24796 {
24797 /* Consider the innermost template arguments, since those are the ones
24798 that come from the template-id; the template arguments for the
24799 enclosing class do not make it type-dependent unless they are used in
24800 the type of the decl. */
24802 && (any_dependent_template_arguments_p
24805 }
24807 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24808 type-dependent. Checking this is important for functions with auto return
24809 type, which looks like a dependent type. */
24818 {
24822 }
24824 /* Always dependent, on the number of arguments if nothing else. */
24829 {
24834 {
24840 }
24841 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24846 {
24851 }
24854 {
24861 }
24871 }
24875 /* Dependent type attributes might not have made it from the decl to
24876 the type yet. */
24882 }
24884 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24885 type-dependent if the expression refers to a member of the current
24886 instantiation and the type of the referenced member is dependent, or the
24887 class member access expression refers to a member of an unknown
24888 specialization.
24890 This function returns true if the OBJECT in such a class member access
24891 expression is of an unknown specialization. */
24893 bool
24895 {
24896 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24897 dependent. */
24902 }
24904 /* walk_tree callback function for instantiation_dependent_expression_p,
24905 below. Returns non-zero if a dependent subexpression is found. */
24907 static tree
24910 {
24912 {
24913 /* We don't have to worry about decltype currently because decltype
24914 of an instantiation-dependent expr is a dependent type. This
24915 might change depending on the resolution of DR 1172. */
24918 }
24921 {
24922 /* Don't treat an argument list as dependent just because it has no
24923 TREE_TYPE. */
24931 /* Handle expressions with type operands. */
24936 {
24941 {
24944 else
24945 {
24948 }
24949 }
24951 }
24955 /* In a template, finish_class_member_access_expr creates a
24956 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24957 type-dependent, so that we can check access control at
24958 instantiation time (PR 42277). See also Core issue 1273. */
24965 else
24968 /* Treat statement-expressions as dependent. */
24972 /* Treat requires-expressions as dependent. */
24977 /* Treat calls to function concepts as dependent. */
24983 /* And variable concepts. */
24990 }
24994 else
24996 }
24998 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24999 sense defined by the ABI:
25001 "An expression is instantiation-dependent if it is type-dependent
25002 or value-dependent, or it has a subexpression that is type-dependent
25003 or value-dependent."
25005 Except don't actually check value-dependence for unevaluated expressions,
25006 because in sizeof(i) we don't care about the value of i. Checking
25007 type-dependence will in turn check value-dependence of array bounds/template
25008 arguments as needed. */
25010 bool
25012 {
25013 tree result;
25024 }
25026 /* As above, but also check value-dependence of the expression as a whole. */
25028 bool
25030 {
25033 }
25035 /* Like type_dependent_expression_p, but it also works while not processing
25036 a template definition, i.e. during substitution or mangling. */
25038 bool
25040 {
25046 }
25048 /* Returns TRUE if ARGS contains a type-dependent expression. */
25050 bool
25052 {
25054 tree arg;
25057 {
25060 }
25062 }
25064 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25065 expressions) contains any type-dependent expressions. */
25067 bool
25069 {
25075 }
25077 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25078 expressions) contains any value-dependent expressions. */
25080 bool
25082 {
25088 }
25090 /* Returns TRUE if the ARG (a template argument) is dependent. */
25092 bool
25094 {
25098 /* Assume a template argument that was wrongly written by the user
25099 is dependent. This is consistent with what
25100 any_dependent_template_arguments_p [that calls this function]
25101 does. */
25111 {
25114 /* A member template of a dependent class is not necessarily
25115 type-dependent, but it is a dependent template argument because it
25116 will be a member of an unknown specialization to that template. */
25119 }
25121 {
25125 {
25128 }
25131 }
25134 else
25137 }
25139 /* Returns true if ARGS (a collection of template arguments) contains
25140 any types that require structural equality testing. */
25142 bool
25144 {
25154 {
25157 {
25163 {
25164 /* Look inside the argument pack. */
25167 }
25170 {
25183 }
25184 }
25185 }
25188 }
25190 /* Returns true if ARGS (a collection of template arguments) contains
25191 any dependent arguments. */
25193 bool
25195 {
25205 {
25210 }
25213 }
25215 /* Returns true if ARGS contains any errors. */
25217 bool
25219 {
25227 {
25230 else
25232 }
25238 {
25243 }
25246 }
25248 /* Returns TRUE if the template TMPL is type-dependent. */
25250 bool
25252 {
25254 {
25259 }
25261 /* Template template parameters are dependent. */
25265 /* So are names that have not been looked up. */
25269 }
25271 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25273 bool
25275 {
25278 }
25280 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25281 are dependent. */
25283 bool
25285 {
25292 {
25314 {
25318 }
25322 {
25326 {
25331 }
25332 }
25333 }
25336 }
25338 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25339 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25340 no such TYPE can be found. Note that this function peers inside
25341 uninstantiated templates and therefore should be used only in
25342 extremely limited situations. ONLY_CURRENT_P restricts this
25343 peering to the currently open classes hierarchy (which is required
25344 when comparing types). */
25346 tree
25348 {
25349 tree scope;
25350 tree name;
25351 tree decl;
25353 tree pushed_scope;
25354 tree result;
25359 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25362 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25363 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25364 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25365 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25366 identifier of the TYPENAME_TYPE anymore.
25367 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25368 TYPENAME_TYPE instead, we avoid messing up with a possible
25369 typedef variant case. */
25372 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25373 it first before we can figure out what NAME refers to. */
25375 {
25377 /* Given a class template A with a dependent base with nested type C,
25378 typedef typename A::C::C C will land us here, as trying to resolve
25379 the initial A::C leads to the local C typedef, which leads back to
25380 A::C::C. So we break the recursion now. */
25382 else
25384 }
25385 /* If we don't know what SCOPE refers to, then we cannot resolve the
25386 TYPENAME_TYPE. */
25389 /* If this is a typedef, we don't want to look inside (c++/11987). */
25392 /* If SCOPE isn't the template itself, it will not have a valid
25393 TYPE_FIELDS list. */
25395 /* scope is either the template itself or a compatible instantiation
25396 like X<T>, so look up the name in the original template. */
25398 /* If scope has no fields, it can't be a current instantiation. Check this
25399 before currently_open_class to avoid infinite recursion (71515). */
25402 /* If the SCOPE is not the current instantiation, there's no reason
25403 to look inside it. */
25406 /* Enter the SCOPE so that name lookup will be resolved as if we
25407 were in the class definition. In particular, SCOPE will no
25408 longer be considered a dependent type. */
25410 /* Look up the declaration. */
25412 tf_warning_or_error);
25416 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25417 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25423 {
25427 }
25430 {
25431 /* Obtain the template and the arguments. */
25434 {
25435 /* We get here with a plain identifier because a previous tentative
25436 parse of the nested-name-specifier as part of a ptr-operator saw
25437 ::template X<A>. The use of ::template is necessary in a
25438 ptr-operator, but wrong in a declarator-id.
25440 [temp.names]: In a qualified-id of a declarator-id, the keyword
25441 template shall not appear at the top level. */
25445 }
25447 /* Instantiate the template. */
25453 }
25455 /* Leave the SCOPE. */
25459 /* If we failed to resolve it, return the original typename. */
25463 /* If lookup found a typename type, resolve that too. */
25465 {
25466 /* Ill-formed programs can cause infinite recursion here, so we
25467 must catch that. */
25471 }
25473 /* Qualify the resulting type. */
25479 }
25481 /* EXPR is an expression which is not type-dependent. Return a proxy
25482 for EXPR that can be used to compute the types of larger
25483 expressions containing EXPR. */
25485 tree
25487 {
25489 tree inner_expr;
25491 /* When checking, try to get a constant value for all non-dependent
25492 expressions in order to expose bugs in *_dependent_expression_p
25493 and constexpr. This can affect code generation, see PR70704, so
25494 only do this for -fchecking=2. */
25497 /* Don't do this during nsdmi parsing as it can lead to
25498 unexpected recursive instantiations. */
25500 /* Don't do this during concept expansion either and for
25501 the same reason. */
25507 /* Preserve OVERLOADs; the functions must be available to resolve
25508 types. */
25519 /* There is no need to return a proxy for a variable. */
25522 /* Preserve string constants; conversions from string constants to
25523 "char *" are allowed, even though normally a "const char *"
25524 cannot be used to initialize a "char *". */
25527 /* Preserve void and arithmetic constants, as an optimization -- there is no
25528 reason to create a new node. */
25533 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25534 There is at least one place where we want to know that a
25535 particular expression is a throw-expression: when checking a ?:
25536 expression, there are special rules if the second or third
25537 argument is a throw-expression. */
25541 /* Don't wrap an initializer list, we need to be able to look inside. */
25545 /* Don't wrap a dummy object, we need to be able to test for it. */
25564 /* If the type is unknown, it can't really be non-dependent */
25567 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25570 }
25572 /* ARGS is a vector of expressions as arguments to a function call.
25573 Replace the arguments with equivalent non-dependent expressions.
25574 This modifies ARGS in place. */
25576 void
25578 {
25580 tree arg;
25583 {
25587 }
25588 }
25590 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25591 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25592 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25594 static tree
25596 {
25610 }
25612 tree
25614 {
25616 }
25618 tree
25620 {
25622 }
25624 /* Return a C++17 deduction placeholder for class template TMPL. */
25626 tree
25628 {
25632 }
25634 /* True iff T is a C++17 class template deduction placeholder. */
25636 bool
25638 {
25640 }
25642 /* Make a "constrained auto" type-specifier. This is an
25643 auto type with constraints that must be associated after
25644 deduction. The constraint is formed from the given
25645 CONC and its optional sequence of arguments, which are
25646 non-null if written as partial-concept-id. */
25648 tree
25650 {
25653 /* Build the constraint. */
25661 /* Our canonical type depends on the constraint. */
25664 /* Attach the constraint to the type declaration. */
25667 }
25669 /* Given type ARG, return std::initializer_list<ARG>. */
25671 static tree
25673 {
25677 {
25681 "deducing from brace-enclosed initializer list"
25685 }
25691 }
25693 /* Replace auto in TYPE with std::initializer_list<auto>. */
25695 static tree
25697 {
25704 }
25706 /* Hash traits for hashing possibly constrained 'auto'
25707 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25710 {
25713 };
25715 /* Hash the 'auto' T. */
25717 inline hashval_t
25719 {
25721 /* Matching constrained-type-specifiers denote the same template
25722 parameter, so hash the constraint. */
25724 else
25725 /* But unconstrained autos are all separate, so just hash the pointer. */
25727 }
25729 /* Compare two 'auto's. */
25733 {
25740 /* Two unconstrained autos are distinct. */
25745 }
25747 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25748 constrained) auto, add it to the vector. */
25750 static int
25752 {
25755 {
25756 /* All the autos were built with index 0; fix that up now. */
25760 /* If this is a repeated constrained-type-specifier, use the index we
25761 chose before. */
25763 else
25764 {
25765 /* Otherwise this is new, so use the current count. */
25768 }
25770 }
25772 /* Always keep walking. */
25774 }
25776 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25777 says they can appear anywhere in the type. */
25779 static tree
25781 {
25790 {
25795 }
25798 }
25800 /* The stem for deduction guide names. */
25803 /* Return the name for a deduction guide for class template TMPL. */
25805 tree
25807 {
25818 }
25820 /* True if NAME is the name of a deduction guide. */
25822 bool
25824 {
25829 }
25831 /* True if FN is a deduction guide. */
25833 bool
25835 {
25840 }
25842 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25844 bool
25846 {
25853 }
25855 /* True if FN is a guide generated from a constructor template. */
25857 bool
25859 {
25867 }
25869 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25870 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25871 template parameter types. Note that the handling of template template
25872 parameters relies on current_template_parms being set appropriately for the
25873 new template. */
25875 static tree
25878 {
25884 tree newtype;
25887 {
25894 }
25895 else
25896 {
25899 {
25900 // Substitute once to fix references to other template parameters.
25903 // Now substitute again to reduce the level of the auto.
25906 }
25907 else
25910 }
25912 tree newdecl
25917 tree newidx;
25920 {
25930 {
25935 // First create a copy (ttargs) of tsubst_args with an
25936 // additional level for the template template parameter's own
25937 // template parameters (ttparms).
25938 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25946 // Substitute ttargs into ttparms to fix references to
25947 // other template parameters.
25950 // Now substitute again with args based on tparms, to reduce
25951 // the level of the ttparms.
25954 complain);
25955 // Finally, tack the adjusted parms onto tparms.
25957 current_template_parms);
25959 }
25960 }
25961 else
25962 {
25964 tree newconst
25976 }
25979 }
25981 /* Returns a C++17 class deduction guide template based on the constructor
25982 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25983 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25985 static tree
25987 {
25991 location_t loc;
25995 {
25999 {
26002 }
26003 else
26013 }
26014 else
26015 {
26019 fn_tmpl
26029 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26030 fully specialized args for the enclosing class. Strip those off, as
26031 the deduction guide won't have those template parameters. */
26034 /* Discard the 'this' parameter. */
26042 {
26045 /* For a member template constructor, we need to flatten the two
26046 template parameter lists into one, and then adjust the function
26047 signature accordingly. This gets...complicated. */
26050 /* For a member template we should have two levels of parms/args, one
26051 for the class and one for the constructor. We stripped
26052 specialized args for further enclosing classes above. */
26056 /* Template args for translating references to the two-level template
26057 parameters into references to the one-level template parameters we
26058 are creating. */
26063 /* Template parms for the constructor template. */
26066 /* Template parms for the class template. */
26070 /* Template parms for the deduction guide start as a copy of the
26071 template parms for the class. We set current_template_parms for
26072 lookup_template_class_1. */
26078 /* Now we need to rewrite the constructor parms to append them to the
26079 class parms. */
26081 {
26098 }
26100 /* Now we have a final set of template parms to substitute into the
26101 function signature. */
26110 }
26115 }
26118 {
26119 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26123 }
26127 FUNCTION_DECL,
26144 }
26146 /* Deduce template arguments for the class template placeholder PTYPE for
26147 template TMPL based on the initializer INIT, and return the resulting
26148 type. */
26150 static tree
26152 tsubst_flags_t complain)
26153 {
26155 {
26156 /* We should have handled this in the caller. */
26162 }
26173 {
26176 {
26177 /* As an exception, the first phase in 16.3.1.7 (considering the
26178 initializer list as a single argument) is omitted if the
26179 initializer list consists of a single expression of type cv U,
26180 where U is a specialization of C or a class derived from a
26181 specialization of C. */
26192 }
26195 else
26197 }
26198 else
26209 /* Prune explicit deduction guides in copy-initialization context. */
26211 {
26217 {
26218 /* Found a nonconverting guide, prune the candidates. */
26225 }
26226 }
26231 {
26234 }
26237 // FIXME cache artificial deduction guides
26239 {
26240 /* Skip inherited constructors. */
26250 else
26254 }
26258 /* If this is list-initialization and the class has a list constructor, first
26259 try deducing from the list as a single argument, as [over.match.list]. */
26263 {
26267 }
26269 {
26275 {
26276 /* That didn't work, now try treating the list as a sequence of
26277 arguments. */
26280 }
26281 }
26283 /* Maybe generate an implicit deduction guide. */
26285 {
26289 /* Generate a copy guide. */
26292 /* Generate a default guide. */
26296 {
26301 }
26302 }
26305 {
26307 " of %qT, as it has no non-explicit deduction guides or "
26310 }
26312 {
26316 }
26319 {
26323 }
26326 {
26336 }
26341 }
26343 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26344 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26345 The CONTEXT determines the context in which auto deduction is performed
26346 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26347 OUTER_TARGS are used during template argument deduction
26348 (context == adc_unify) to properly substitute the result, and is ignored
26349 in other contexts.
26351 For partial-concept-ids, extra args may be appended to the list of deduced
26352 template arguments prior to determining constraint satisfaction. */
26354 tree
26358 {
26359 tree targs;
26366 /* Defining a subset of type-dependent expressions that we can deduce
26367 from ahead of time isn't worth the trouble. */
26370 /* Similarly, we can't deduce from another undeduced decl. */
26375 /* C++17 class template argument deduction. */
26379 /* Nothing we can do with this, even in deduction context. */
26382 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26383 with either a new invented type template parameter U or, if the
26384 initializer is a braced-init-list (8.5.4), with
26385 std::initializer_list<U>. */
26387 {
26392 else
26393 {
26395 {
26399 "for deduction to %<std::initializer_list%>, use copy-"
26401 }
26403 }
26404 }
26415 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26416 and initializer has array type, deduce cv-qualified array type. */
26418 complain);
26420 {
26429 {
26433 }
26434 }
26435 else
26436 {
26438 tree tparms;
26442 else
26443 {
26447 }
26454 {
26456 /* Try again at instantiation time. */
26460 /* If type is error_mark_node a diagnostic must have been
26461 emitted by now. Also, having a mention to '<type error>'
26462 in the diagnostic is not really useful to the user. */
26463 {
26467 else
26472 }
26474 }
26475 }
26477 /* Check any placeholder constraints against the deduced type. */
26480 {
26481 /* Use the deduced type to check the associated constraints. If we
26482 have a partial-concept-id, rebuild the argument list so that
26483 we check using the extra arguments. */
26487 {
26490 }
26491 else
26494 {
26496 {
26498 {
26516 }
26518 }
26520 }
26521 }
26527 }
26529 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26530 result. */
26532 tree
26534 {
26536 {
26542 /* In an abbreviated function template we didn't know we were dealing
26543 with a function template when we saw the auto return type, so update
26544 it to have the correct level. */
26546 }
26548 }
26550 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26551 'decltype(auto)' or a deduced class template. */
26553 bool
26555 {
26561 else
26563 }
26565 /* for_each_template_parm callback for type_uses_auto. */
26567 int
26569 {
26571 }
26573 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26574 a use of `auto'. Returns NULL_TREE otherwise. */
26576 tree
26578 {
26582 {
26583 /* The Concepts TS allows multiple autos in one type-specifier; just
26584 return the first one we find, do_auto_deduction will collect all of
26585 them. */
26589 else
26591 }
26592 else
26594 }
26596 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26597 concepts are enabled, auto is acceptable in template arguments, but
26598 only when TEMPL identifies a template class. Return TRUE if any
26599 such errors were reported. */
26601 bool
26603 {
26604 /* If there were previous errors, nevermind. */
26608 /* If TMPL is an identifier, we're parsing and we can't tell yet
26609 whether TMPL is supposed to be a type, a function or a variable.
26610 We'll only be able to tell during template substitution, so we
26611 expect to be called again then. If concepts are enabled and we
26612 know we have a type, we're ok. */
26620 /* Quickly search for any occurrences of auto; usually there won't
26621 be any, and then we'll avoid allocating the vector. */
26629 {
26634 }
26637 }
26639 /* For a given template T, return the vector of typedefs referenced
26640 in T for which access check is needed at T instantiation time.
26641 T is either a FUNCTION_DECL or a RECORD_TYPE.
26642 Those typedefs were added to T by the function
26643 append_type_to_template_for_access_check. */
26647 {
26648 tree ti;
26659 {
26664 }
26667 }
26669 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26670 tied to T. That list of typedefs will be access checked at
26671 T instantiation time.
26672 T is either a FUNCTION_DECL or a RECORD_TYPE.
26673 TYPE_DECL is a TYPE_DECL node representing a typedef.
26674 SCOPE is the scope through which TYPE_DECL is accessed.
26675 LOCATION is the location of the usage point of TYPE_DECL.
26677 This function is a subroutine of
26678 append_type_to_template_for_access_check. */
26680 static void
26682 tree type_decl,
26683 tree scope,
26684 location_t location)
26685 {
26686 qualified_typedef_usage_t typedef_usage;
26687 tree ti;
26694 && type_decl
26708 }
26710 /* Append TYPE_DECL to the template TEMPL.
26711 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26712 At TEMPL instanciation time, TYPE_DECL will be checked to see
26713 if it can be accessed through SCOPE.
26714 LOCATION is the location of the usage point of TYPE_DECL.
26716 e.g. consider the following code snippet:
26718 class C
26719 {
26720 typedef int myint;
26721 };
26723 template<class U> struct S
26724 {
26725 C::myint mi; // <-- usage point of the typedef C::myint
26726 };
26728 S<char> s;
26730 At S<char> instantiation time, we need to check the access of C::myint
26731 In other words, we need to check the access of the myint typedef through
26732 the C scope. For that purpose, this function will add the myint typedef
26733 and the scope C through which its being accessed to a list of typedefs
26734 tied to the template S. That list will be walked at template instantiation
26735 time and access check performed on each typedefs it contains.
26736 Note that this particular code snippet should yield an error because
26737 myint is private to C. */
26739 void
26741 tree type_decl,
26742 tree scope,
26743 location_t location)
26744 {
26750 /* Make sure we don't append the type to the template twice. */
26757 }
26759 /* Convert the generic type parameters in PARM that match the types given in the
26760 range [START_IDX, END_IDX) from the current_template_parms into generic type
26761 packs. */
26763 tree
26765 {
26776 {
26777 /* Create a distinct parameter pack type from the current parm and add it
26778 to the replacement args to tsubst below into the generic function
26779 parameter. */
26794 }
26800 /* If there are more levels then build up the replacement with the outer
26801 template parms. */
26805 replacement);
26808 }
26810 /* Entries in the decl_constraint hash table. */
26812 {
26813 tree decl;
26814 tree ci;
26815 };
26817 /* Hashing function and equality for constraint entries. */
26819 {
26821 {
26823 }
26826 {
26828 }
26829 };
26831 /* A mapping from declarations to constraint information. Note that
26832 both templates and their underlying declarations are mapped to the
26833 same constraint information.
26835 FIXME: This is defined in pt.c because garbage collection
26836 code is not being generated for constraint.cc. */
26840 /* Returns the template constraints of declaration T. If T is not
26841 constrained, return NULL_TREE. Note that T must be non-null. */
26843 tree
26845 {
26856 else
26858 }
26860 /* Associate the given constraint information CI with the declaration
26861 T. If T is a template, then the constraints are associated with
26862 its underlying declaration. Don't build associations if CI is
26863 NULL_TREE. */
26865 void
26867 {
26879 }
26881 /* Remove the associated constraints of the declaration T. */
26883 void
26885 {
26894 }
26896 /* Memoized satisfaction results for declarations. This
26897 maps the pair (constraint_info, arguments) to the result computed
26898 by constraints_satisfied_p. */
26901 {
26902 tree ci;
26903 tree args;
26904 tree result;
26905 };
26907 /* Hashing function and equality for constraint entries. */
26910 {
26912 {
26915 }
26918 {
26920 }
26921 };
26923 /* Memoized satisfaction results for concept checks. */
26926 {
26927 tree tmpl;
26928 tree args;
26929 tree result;
26930 };
26932 /* Hashing function and equality for constraint entries. */
26935 {
26937 {
26939 }
26942 {
26947 }
26948 };
26953 /* Search for a memoized satisfaction result. Returns one of the
26954 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26956 tree
26958 {
26963 else
26965 }
26967 /* Memoize the result of a satisfication test. Returns the saved result. */
26969 tree
26971 {
26978 }
26980 /* Search for a memoized satisfaction result for a concept. */
26982 tree
26984 {
26989 else
26991 }
26993 /* Memoize the result of a concept check. Returns the saved result. */
26995 tree
26997 {
27004 }
27008 /* Returns a prior concept specialization. This returns the substituted
27009 and normalized constraints defined by the concept. */
27011 tree
27013 {
27018 else
27020 }
27022 /* Save a concept expansion for later. */
27024 tree
27026 {
27033 }
27035 static hashval_t
27037 {
27046 }
27048 /* Compare the constraints of two subsumption entries. The LEFT1 and
27049 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27050 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27052 static bool
27054 {
27062 }
27064 /* Key/value pair for learning and memoizing subsumption results. This
27065 associates a pair of check constraints (including arguments) with
27066 a boolean value indicating the result. */
27069 {
27070 tree t1;
27071 tree t2;
27073 };
27075 /* Hashing function and equality for constraint entries. */
27078 {
27080 {
27082 }
27085 {
27090 }
27091 };
27095 /* Search for a previously cached subsumption result. */
27099 {
27104 else
27106 }
27108 /* Save a subsumption result. */
27110 bool
27112 {
27119 }
27121 /* Set up the hash table for constraint association. */
27123 void
27125 {
27134 }
27136 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27137 0..N-1. */
27139 void
27141 {
27144 integer_type_node,
27145 NULL_TREE),
27149 }
27151 /* Set up the hash tables for template instantiations. */
27153 void
27155 {
27161 }
27163 /* Print stats about the template hash tables for -fstats. */
27165 void
27167 {
27176 }
27178 #if CHECKING_P
27182 /* Verify that build_non_dependent_expr () works, for various expressions,
27183 and that location wrappers don't affect the results. */
27185 static void
27187 {
27190 /* Verify constants, without and with location wrappers. */
27207 }
27209 /* Verify that type_dependent_expression_p () works correctly, even
27210 in the presence of location wrapper nodes. */
27212 static void
27214 {
27219 /* If no templates are involved, nothing is type-dependent. */
27225 /* Within a template, an unresolved name is always type-dependent. */
27228 /* Ensure it copes with NULL_TREE and errors. */
27232 /* A USING_DECL in a template should be type-dependent, even if wrapped
27233 with a location wrapper (PR c++/83799). */
27242 }
27244 /* Run all of the selftests within this file. */
27246 void
27248 {
27251 }