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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 }
10907 }
10909 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10910 such a thing will already have been added to the field
10911 list by tsubst_enum in finish_member_declaration in the
10912 CLASSTYPE_NESTED_UTDS case above. */
10916 {
10919 }
10920 }
10921 }
10922 }
10923 }
10924 else
10925 {
10928 {
10929 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10935 {
10936 /* template <class T> friend class C; */
10939 }
10941 {
10942 /* template <class T> friend class C::D; */
10948 }
10951 {
10952 /* This could be either
10954 friend class T::C;
10956 when dependent_type_p is false or
10958 template <class U> friend class T::C;
10960 otherwise. */
10961 /* Bump processing_template_decl in case this is something like
10962 template <class T> friend struct A<T>::B. */
10969 }
10973 {
10974 /* friend class C;
10976 where C hasn't been declared yet. Let's lookup name
10977 from namespace scope directly, bypassing any name that
10978 come from dependent base class. */
10981 /* The call to xref_tag_from_type does injection for friend
10982 classes. */
10984 friend_type =
10988 }
10990 /* friend class C<T>; */
10993 /* Otherwise it's
10995 friend class C;
10997 where C is already declared or
10999 friend class C<int>;
11001 We don't have to do anything in these cases. */
11004 /* Trick make_friend_class into realizing that the friend
11005 we're adding is a template, not an ordinary class. It's
11006 important that we use make_friend_class since it will
11007 perform some error-checking and output cross-reference
11008 information. */
11016 }
11017 else
11018 {
11019 /* Build new DECL_FRIENDLIST. */
11020 tree r;
11022 /* The file and line for this declaration, to
11023 assist in error message reporting. Since we
11024 called push_tinst_level above, we don't need to
11025 restore these. */
11029 {
11032 }
11037 {
11040 }
11041 }
11042 }
11043 }
11046 {
11047 /* Restore these before substituting into the lambda capture
11048 initializers. */
11051 }
11053 /* Set the file and line number information to whatever is given for
11054 the class itself. This puts error messages involving generated
11055 implicit functions at a predictable point, and the same point
11056 that would be used for non-template classes. */
11063 /* We don't instantiate default arguments for member functions. 14.7.1:
11065 The implicit instantiation of a class template specialization causes
11066 the implicit instantiation of the declarations, but not of the
11067 definitions or default arguments, of the class member functions,
11068 member classes, static data members and member templates.... */
11070 /* Some typedefs referenced from within the template code need to be access
11071 checked at template instantiation time, i.e now. These types were
11072 added to the template at parsing time. Let's get those and perform
11073 the access checks then. */
11083 /* The vtable for a template class can be emitted in any translation
11084 unit in which the class is instantiated. When there is no key
11085 method, however, finish_struct_1 will already have added TYPE to
11086 the keyed_classes. */
11091 }
11093 /* Wrapper for instantiate_class_template_1. */
11095 tree
11097 {
11098 tree ret;
11103 }
11105 static tree
11107 {
11108 tree r;
11114 else
11115 {
11122 }
11124 }
11126 /* Given a function parameter pack TMPL_PARM and some function parameters
11127 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11128 and set *SPEC_P to point at the next point in the list. */
11130 tree
11132 {
11133 /* Collect all of the extra "packed" parameters into an
11134 argument pack. */
11135 tree parmvec;
11145 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11149 {
11154 }
11156 /* Build the argument packs. */
11161 }
11163 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11164 NONTYPE_ARGUMENT_PACK. */
11166 static tree
11168 {
11170 }
11172 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11173 pack expansion with no extra args, 2 if it has extra args, or 0
11174 if it is not a pack expansion. */
11176 static int
11178 {
11184 /* A decl pack is itself an expansion. */
11191 }
11194 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11196 static tree
11198 {
11205 }
11207 /* This is a subroutine of tsubst_pack_expansion.
11209 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11210 mechanism to store the (non complete list of) arguments of the
11211 substitution and return a non substituted pack expansion, in order
11212 to wait for when we have enough arguments to really perform the
11213 substitution. */
11215 static bool
11219 {
11220 /* If one pack has an expansion and another pack has a normal
11221 argument or if one pack has an empty argument and an another
11222 one hasn't then tsubst_pack_expansion cannot perform the
11223 substitution and need to fall back on the
11224 PACK_EXPANSION_EXTRA mechanism. */
11232 {
11235 parm_pack;
11237 {
11242 /* We can't substitute a pack expansion with extra args into
11243 our pattern. */
11247 else
11249 }
11253 }
11255 }
11257 /* [temp.variadic]/6 says that:
11259 The instantiation of a pack expansion [...]
11260 produces a list E1,E2, ..., En, where N is the number of elements
11261 in the pack expansion parameters.
11263 This subroutine of tsubst_pack_expansion produces one of these Ei.
11265 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11266 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11267 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11268 INDEX is the index 'i' of the element Ei to produce. ARGS,
11269 COMPLAIN, and IN_DECL are the same parameters as for the
11270 tsubst_pack_expansion function.
11272 The function returns the resulting Ei upon successful completion,
11273 or error_mark_node.
11275 Note that this function possibly modifies the ARGS parameter, so
11276 it's the responsibility of the caller to restore it. */
11278 static tree
11280 tree parm_packs,
11282 tree args /* This parm gets
11284 tsubst_flags_t complain,
11285 tree in_decl)
11286 {
11287 tree t;
11290 /* For each parameter pack, change the substitution of the parameter
11291 pack to the ith argument in its argument pack, then expand the
11292 pattern. */
11294 {
11299 ith_elem_is_expansion |=
11302 /* Select the Ith argument from the pack. */
11306 {
11308 {
11313 }
11314 else
11316 }
11317 else
11318 {
11323 {
11325 /* Update the corresponding argument. */
11327 }
11328 else
11329 /* Re-use the ARGUMENT_PACK_SELECT. */
11331 }
11333 }
11335 /* Substitute into the PATTERN with the (possibly altered)
11336 arguments. */
11338 /* Expanding a fixed parameter pack from
11339 coerce_template_parameter_pack. */
11344 {
11347 else
11350 }
11354 else
11357 /* If the Ith argument pack element is a pack expansion, then
11358 the Ith element resulting from the substituting is going to
11359 be a pack expansion as well. */
11364 }
11366 /* When the unexpanded parameter pack in a fold expression expands to an empty
11367 sequence, the value of the expression is as follows; the program is
11368 ill-formed if the operator is not listed in this table.
11370 && true
11371 || false
11372 , void() */
11374 tree
11376 {
11380 {
11389 }
11395 }
11397 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11398 form an expression that combines the two terms using the
11399 operator of T. */
11401 static tree
11403 {
11407 // Handle compound assignment operators.
11412 {
11422 complain);
11423 }
11424 }
11426 /* Substitute ARGS into the pack of a fold expression T. */
11430 {
11432 }
11434 /* Substitute ARGS into the pack of a fold expression T. */
11438 {
11440 }
11442 /* Expand a PACK of arguments into a grouped as left fold.
11443 Given a pack containing elements A0, A1, ..., An and an
11444 operator @, this builds the expression:
11446 ((A0 @ A1) @ A2) ... @ An
11448 Note that PACK must not be empty.
11450 The operator is defined by the original fold expression T. */
11452 static tree
11454 {
11457 {
11460 }
11462 }
11464 /* Substitute into a unary left fold expression. */
11466 static tree
11468 tree in_decl)
11469 {
11474 {
11478 }
11481 else
11483 }
11485 /* Substitute into a binary left fold expression.
11487 Do ths by building a single (non-empty) vector of argumnts and
11488 building the expression from those elements. */
11490 static tree
11492 tree in_decl)
11493 {
11502 {
11507 }
11515 }
11517 /* Expand a PACK of arguments into a grouped as right fold.
11518 Given a pack containing elementns A0, A1, ..., and an
11519 operator @, this builds the expression:
11521 A0@ ... (An-2 @ (An-1 @ An))
11523 Note that PACK must not be empty.
11525 The operator is defined by the original fold expression T. */
11527 tree
11529 {
11530 // Build the expression.
11534 {
11537 }
11539 }
11541 /* Substitute into a unary right fold expression. */
11543 static tree
11545 tree in_decl)
11546 {
11551 {
11555 }
11558 else
11560 }
11562 /* Substitute into a binary right fold expression.
11564 Do ths by building a single (non-empty) vector of arguments and
11565 building the expression from those elements. */
11567 static tree
11569 tree in_decl)
11570 {
11579 {
11584 }
11593 }
11595 /* Walk through the pattern of a pack expansion, adding everything in
11596 local_specializations to a list. */
11598 struct el_data
11599 {
11600 tree extra;
11601 tsubst_flags_t complain;
11602 };
11603 static tree
11605 {
11610 {
11612 {
11613 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11616 {
11622 }
11624 {
11625 /* Handle lambda capture here, since we aren't doing any
11626 substitution now, and so tsubst_copy won't call
11627 process_outer_var_ref. */
11631 {
11637 {
11638 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11639 proxies. */
11641 {
11646 }
11648 }
11649 }
11650 }
11651 }
11655 }
11657 }
11658 static tree
11660 {
11664 }
11666 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11667 for use in PACK_EXPANSION_EXTRA_ARGS. */
11669 tree
11671 {
11677 }
11679 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11680 normal template args to ARGS. */
11682 tree
11684 {
11686 {
11688 {
11689 /* The partial instantiation involved local declarations collected in
11690 extract_local_specs; map from the general template to our local
11691 context. */
11697 /* else inst is already a full instantiation of the pack. */
11699 }
11702 }
11704 }
11706 /* Substitute ARGS into T, which is an pack expansion
11707 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11708 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11709 (if only a partial substitution could be performed) or
11710 ERROR_MARK_NODE if there was an error. */
11711 tree
11713 tree in_decl)
11714 {
11715 tree pattern;
11720 tree result;
11728 /* Add in any args remembered from an earlier partial instantiation. */
11733 /* Determine the argument packs that will instantiate the parameter
11734 packs used in the expansion expression. While we're at it,
11735 compute the number of arguments to be expanded and make sure it
11736 is consistent. */
11739 {
11746 {
11752 complain);
11753 else
11757 }
11759 {
11760 /* ??? Support use in other patterns. */
11764 }
11766 {
11767 /* We know we have correct local_specializations if this
11768 expansion is at function scope, or if we're dealing with a
11769 local parameter in a requires expression; for the latter,
11770 tsubst_requires_expr set it up appropriately. */
11773 else
11774 /* We can't rely on local_specializations for a parameter
11775 name used later in a function declaration (such as in a
11776 late-specified return type). Even if it exists, it might
11777 have the wrong value for a recursive call. */
11781 {
11782 /* This parameter pack was used in an unevaluated context. Just
11783 make a dummy decl, since it's only used for its type. */
11788 /* Partial instantiation of the parm_pack, we can't build
11789 up an argument pack yet. */
11791 else
11793 }
11795 /* This argument pack isn't fully instantiated yet. We set this
11796 flag rather than clear arg_pack because we do want to do the
11797 optimization below, and we don't want to substitute directly
11798 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11799 where it isn't expected). */
11801 }
11803 {
11807 }
11808 else
11809 {
11815 }
11822 /* This can only happen if we forget to expand an argument
11823 pack somewhere else. Just return an error, silently. */
11824 {
11828 }
11831 {
11835 /* Don't bother trying to do a partial substitution with
11836 incomplete packs; we'll try again after deduction. */
11844 {
11849 pattern);
11850 else
11852 pattern);
11854 }
11856 /* Keep track of the parameter packs and their corresponding
11857 argument packs. */
11860 }
11861 else
11862 {
11863 /* We can't substitute for this parameter pack. We use a flag as
11864 well as the missing_level counter because function parameter
11865 packs don't have a level. */
11868 }
11869 }
11871 /* If the expansion is just T..., return the matching argument pack, unless
11872 we need to call convert_from_reference on all the elements. This is an
11873 important optimization; see c++/68422. */
11876 {
11879 /* If the argument pack is a single pack expansion, pull it out. */
11884 /* Types need no adjustment, nor does sizeof..., and if we still have
11885 some pack expansion args we won't do anything yet. */
11890 /* Also optimize expression pack expansions if we can tell that the
11891 elements won't have reference type. */
11897 /* Otherwise use the normal path so we get convert_from_reference. */
11898 }
11900 /* We cannot expand this expansion expression, because we don't have
11901 all of the argument packs we need. */
11903 {
11904 /* We got some full packs, but we can't substitute them in until we
11905 have values for all the packs. So remember these until then. */
11911 }
11913 {
11914 /* There were no real arguments, we're just replacing a parameter
11915 pack with another version of itself. Substitute into the
11916 pattern and return a PACK_EXPANSION_*. The caller will need to
11917 deal with that. */
11921 else
11925 }
11930 {
11931 /* We're in a late-specified return type, so create our own local
11932 specializations map; the current map is either NULL or (in the
11933 case of recursive unification) might have bindings that we don't
11934 want to use or alter. */
11937 }
11939 /* For each argument in each argument pack, substitute into the
11940 pattern. */
11944 {
11946 i,
11948 in_decl);
11951 {
11954 }
11955 }
11957 /* Update ARGS to restore the substitution from parameter packs to
11958 their argument packs. */
11960 {
11967 else
11968 {
11976 /* Update the corresponding argument. */
11980 else
11982 }
11983 }
11986 {
11989 }
11991 /* If the dependent pack arguments were such that we end up with only a
11992 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11998 }
12000 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12001 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12002 parameter packs; all parms generated from a function parameter pack will
12003 have the same DECL_PARM_INDEX. */
12005 tree
12007 {
12009 tree patparm;
12012 {
12018 }
12019 else
12020 {
12025 }
12028 }
12030 /* Make an argument pack out of the TREE_VEC VEC. */
12032 static tree
12034 {
12035 tree pack;
12039 else
12040 {
12043 }
12046 }
12048 /* Return an exact copy of template args T that can be modified
12049 independently. */
12051 static tree
12053 {
12061 {
12066 }
12072 }
12074 /* Substitute ARGS into the vector or list of template arguments T. */
12076 static tree
12078 {
12090 {
12092 tree new_arg;
12097 {
12098 /* Substitute into an expansion expression. */
12102 /* Add to the expanded length adjustment the number of
12103 expanded arguments. We subtract one from this
12104 measurement, because the argument pack expression
12105 itself is already counted as 1 in
12106 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12107 the argument pack is empty. */
12109 }
12111 {
12112 /* Substitute into each of the arguments. */
12121 else
12126 }
12127 else
12136 }
12141 /* Make space for the expanded arguments coming from template
12142 argument packs. */
12144 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12145 arguments for a member template.
12146 In that case each TREE_VEC in ORIG_T represents a level of template
12147 arguments, and ORIG_T won't carry any non defaulted argument count.
12148 It will rather be the nested TREE_VECs that will carry one.
12149 In other words, ORIG_T carries a non defaulted argument count only
12150 if it doesn't contain any nested TREE_VEC. */
12152 {
12156 }
12158 {
12162 {
12165 /* Now expand the template argument pack "in place". */
12168 }
12169 else
12170 {
12172 out++;
12173 }
12174 }
12177 }
12179 /* Substitute ARGS into one level PARMS of template parameters. */
12181 static tree
12183 {
12190 {
12198 }
12201 }
12203 /* Return the result of substituting ARGS into the template parameters
12204 given by PARMS. If there are m levels of ARGS and m + n levels of
12205 PARMS, then the result will contain n levels of PARMS. For
12206 example, if PARMS is `template <class T> template <class U>
12207 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12208 result will be `template <int*, double, class V>'. */
12210 static tree
12212 {
12216 /* When substituting into a template, we must set
12217 PROCESSING_TEMPLATE_DECL as the template parameters may be
12218 dependent if they are based on one-another, and the dependency
12219 predicates are short-circuit outside of templates. */
12226 {
12233 }
12238 }
12240 /* Return the result of substituting ARGS into one template parameter
12241 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12242 parameter and which TREE_PURPOSE is the default argument of the
12243 template parameter. */
12245 static tree
12247 {
12268 }
12270 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12271 type T. If T is not an aggregate or enumeration type, it is
12272 handled as if by tsubst. IN_DECL is as for tsubst. If
12273 ENTERING_SCOPE is nonzero, T is the context for a template which
12274 we are presently tsubst'ing. Return the substituted value. */
12276 static tree
12278 tree args,
12279 tsubst_flags_t complain,
12280 tree in_decl,
12282 {
12287 {
12292 /* Fall through. */
12296 {
12297 tree argvec;
12298 tree context;
12299 tree r;
12303 /* In "sizeof(X<I>)" we need to evaluate "I". */
12309 /* First, determine the context for the type we are looking
12310 up. */
12313 {
12316 /* If context is a nested class inside a class template,
12317 it may still need to be instantiated (c++/33959). */
12319 }
12321 /* Then, figure out what arguments are appropriate for the
12322 type we are trying to find. For example, given:
12324 template <class T> struct S;
12325 template <class T, class U> void f(T, U) { S<U> su; }
12327 and supposing that we are instantiating f<int, double>,
12328 then our ARGS will be {int, double}, but, when looking up
12329 S we only want {double}. */
12334 else
12335 {
12339 }
12345 }
12346 else
12347 /* This is not a template type, so there's nothing to do. */
12352 }
12353 }
12357 /* Substitute into the default argument ARG (a default argument for
12358 FN), which has the indicated TYPE. */
12360 tree
12362 tsubst_flags_t complain)
12363 {
12368 /* This can happen in invalid code. */
12386 /* This default argument came from a template. Instantiate the
12387 default argument here, not in tsubst. In the case of
12388 something like:
12390 template <class T>
12391 struct S {
12392 static T t();
12393 void f(T = t());
12394 };
12396 we must be careful to do name lookup in the scope of S<T>,
12397 rather than in the current class. */
12399 /* The "this" pointer is not valid in a default argument. */
12401 {
12406 }
12411 /* The default argument expression may cause implicitly defined
12412 member functions to be synthesized, which will result in garbage
12413 collection. We must treat this situation as if we were within
12414 the body of function so as to avoid collecting live data on the
12415 stack. */
12425 /* Restore the "this" pointer. */
12427 {
12430 }
12437 /* Make sure the default argument is reasonable. */
12443 {
12447 }
12450 }
12452 /* Substitute into all the default arguments for FN. */
12454 static void
12456 {
12457 tree arg;
12458 tree tmpl_args;
12462 /* If this function is not yet instantiated, we certainly don't need
12463 its default arguments. */
12466 /* Don't do this again for clones. */
12472 arg;
12478 complain);
12479 }
12481 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12483 static tree
12485 tree lambda_fntype)
12486 {
12491 /* Nobody should be tsubst'ing into non-template functions. */
12495 {
12496 /* If T is not dependent, just return it. */
12500 /* Calculate the most general template of which R is a
12501 specialization. */
12504 /* We're substituting a lambda function under tsubst_lambda_expr but not
12505 directly from it; find the matching function we're already inside.
12506 But don't do this if T is a generic lambda with a single level of
12507 template parms, as in that case we're doing a normal instantiation. */
12513 /* Calculate the complete set of arguments used to
12514 specialize R. */
12516 (DECL_TEMPLATE_RESULT
12522 /* Check to see if we already have this specialization. */
12524 {
12528 }
12530 /* We can see more levels of arguments than parameters if
12531 there was a specialization of a member template, like
12532 this:
12534 template <class T> struct S { template <class U> void f(); }
12535 template <> template <class U> void S<int>::f(U);
12537 Here, we'll be substituting into the specialization,
12538 because that's where we can find the code we actually
12539 want to generate, but we'll have enough arguments for
12540 the most general template.
12542 We also deal with the peculiar case:
12544 template <class T> struct S {
12545 template <class U> friend void f();
12546 };
12547 template <class U> void f() {}
12548 template S<int>;
12549 template void f<double>();
12551 Here, the ARGS for the instantiation of will be {int,
12552 double}. But, we only need as many ARGS as there are
12553 levels of template parameters in CODE_PATTERN. We are
12554 careful not to get fooled into reducing the ARGS in
12555 situations like:
12557 template <class T> struct S { template <class U> void f(U); }
12558 template <class T> template <> void S<T>::f(int) {}
12560 which we can spot because the pattern will be a
12561 specialization in this case. */
12568 }
12569 else
12570 {
12571 /* This special case arises when we have something like this:
12573 template <class T> struct S {
12574 friend void f<int>(int, double);
12575 };
12577 Here, the DECL_TI_TEMPLATE for the friend declaration
12578 will be an IDENTIFIER_NODE. We are being called from
12579 tsubst_friend_function, and we want only to create a
12580 new decl (R) with appropriate types so that we can call
12581 determine_specialization. */
12584 }
12601 /* If we hit excessive deduction depth, the type is bogus even if
12602 it isn't error_mark_node, so don't build a decl. */
12606 /* We do NOT check for matching decls pushed separately at this
12607 point, as they may not represent instantiations of this
12608 template, and in any case are considered separate under the
12609 discrete model. */
12613 /* Clear out the mangled name and RTL for the instantiation. */
12616 /* Leave DECL_INITIAL set on deleted instantiations. */
12621 /* OpenMP UDRs have the only argument a reference to the declared
12622 type. We want to diagnose if the declared type is a reference,
12623 which is invalid, but as references to references are usually
12624 quietly merged, diagnose it here. */
12626 {
12627 tree argtype
12632 "reference type %qT in "
12636 argtype);
12637 }
12640 /* Type-conversion operator. Reconstruct the name, in
12641 case it's the name of one of the template's parameters. */
12651 {
12655 }
12662 /* If this is an instantiation of a function with internal
12663 linkage, we already know what object file linkage will be
12664 assigned to the instantiation. */
12673 /* We'll re-clone as appropriate in instantiate_template. */
12676 /* If we aren't complaining now, return on error before we register
12677 the specialization so that we'll complain eventually. */
12683 /* When instantiating a constrained member, substitute
12684 into the constraints to create a new constraint. */
12687 {
12690 }
12692 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12693 this in the special friend case mentioned above where
12694 GEN_TMPL is NULL. */
12696 {
12701 tree new_r
12704 /* We instantiated this while substituting into
12705 the type earlier (template/friend54.C). */
12708 /* We're not supposed to instantiate default arguments
12709 until they are called, for a template. But, for a
12710 declaration like:
12712 template <class T> void f ()
12713 { extern void g(int i = T()); }
12715 we should do the substitution when the template is
12716 instantiated. We handle the member function case in
12717 instantiate_class_template since the default arguments
12718 might refer to other members of the class. */
12723 }
12724 else
12727 /* Copy the list of befriending classes. */
12731 {
12735 }
12738 {
12742 /* If this is an instantiation of a member template, clone it.
12743 If it isn't, that'll be handled by
12744 clone_constructors_and_destructors. */
12747 }
12758 /* Possibly limit visibility based on template args. */
12761 {
12765 }
12774 }
12776 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12778 static tree
12780 tree lambda_fntype)
12781 {
12782 /* We can get here when processing a member function template,
12783 member class template, or template template parameter. */
12786 tree spec;
12787 tree tmpl_args;
12788 tree full_args;
12789 tree r;
12793 {
12794 /* Template template parameter is treated here. */
12798 /* If we get a real template back, return it. This can happen in
12799 the context of most_specialized_partial_spec. */
12802 else
12803 /* The new TEMPLATE_DECL was built in
12804 reduce_template_parm_level. */
12807 }
12810 {
12811 /* We might already have an instance of this template.
12812 The ARGS are for the surrounding class type, so the
12813 full args contain the tsubst'd args for the context,
12814 plus the innermost args from the template decl. */
12818 /* Because this is a template, the arguments will still be
12819 dependent, even after substitution. If
12820 PROCESSING_TEMPLATE_DECL is not set, the dependency
12821 predicates will short-circuit. */
12829 /* If this is a default template template argument,
12830 tsubst might not have changed anything. */
12838 }
12840 /* Make a new template decl. It will be similar to the
12841 original, but will record the current template arguments.
12842 We also create a new function declaration, which is just
12843 like the old one, but points to this new template, rather
12844 than the old one. */
12849 // Build new template info linking to the original template decl.
12851 {
12854 }
12855 else
12858 /* The template parameters for this new template are all the
12859 template parameters for the old template, except the
12860 outermost level of parameters. */
12863 complain);
12867 {
12868 tree new_type;
12876 /* For a partial specialization, we need to keep pointing to
12877 the primary template. */
12883 }
12884 else
12885 {
12886 tree new_decl;
12890 else
12900 {
12903 }
12904 else
12905 {
12908 }
12909 }
12919 /* Record this non-type partial instantiation. */
12925 }
12927 /* True if FN is the op() for a lambda in an uninstantiated template. */
12929 bool
12931 {
12936 }
12938 /* We're instantiating a variable from template function TCTX. Return the
12939 corresponding current enclosing scope. This gets complicated because lambda
12940 functions in templates are regenerated rather than instantiated, but generic
12941 lambda functions are subsequently instantiated. */
12943 static tree
12945 {
12954 {
12967 }
12969 }
12971 /* Substitute the ARGS into the T, which is a _DECL. Return the
12972 result of the substitution. Issue error and warning messages under
12973 control of COMPLAIN. */
12975 static tree
12977 {
12978 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12979 location_t saved_loc;
12984 /* Set the filename and linenumber to improve error-reporting. */
12989 {
12999 {
13007 {
13008 /* If there is a local specialization that isn't a
13009 parameter pack, it means that we're doing a "simple"
13010 substitution from inside tsubst_pack_expansion. Just
13011 return the local specialization (which will be a single
13012 parm). */
13019 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13020 the parameters in this function parameter pack. */
13024 {
13027 /* Zero-length parameter packs are boring. Just substitute
13028 into the chain. */
13032 }
13033 else
13034 {
13035 /* All we did was update the type. Make a note of that. */
13038 }
13039 }
13041 /* Loop through all of the parameters we'll build. When T is
13042 a function parameter pack, LEN is the number of expanded
13043 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13046 {
13053 /* We're on the Ith parameter of the function parameter
13054 pack. */
13055 {
13056 /* Get the Ith type. */
13059 /* Rename the parameter to include the index. */
13062 }
13064 /* We're dealing with a normal parameter. */
13072 {
13075 else
13078 }
13088 /* Keep track of the first new parameter we
13089 generate. That's what will be returned to the
13090 caller. */
13094 /* Build a proper chain of parameters when substituting
13095 into a function parameter pack. */
13098 }
13100 /* If cp_unevaluated_operand is set, we're just looking for a
13101 single dummy parameter, so don't keep going. */
13106 /* FIRST_R contains the start of the chain we've built. */
13108 }
13112 {
13119 {
13120 /* This field is a lambda capture pack. Return a TREE_VEC of
13121 the expanded fields to instantiate_class_template_1. */
13125 {
13128 }
13129 else
13130 {
13131 /* All we did was update the type. Make a note of that. */
13134 }
13135 }
13138 {
13141 {
13145 }
13155 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13156 number of bits. */
13162 {
13163 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13164 NSDMI in perform_member_init. Still set DECL_INITIAL
13165 so that we know there is one. */
13170 }
13171 /* We don't have to set DECL_CONTEXT here; it is set by
13172 finish_member_declaration. */
13180 }
13184 }
13188 /* We reach here only for member using decls. We also need to check
13189 uses_template_parms because DECL_DEPENDENT_P is not set for a
13190 using-declaration that designates a member of the current
13191 instantiation (c++/53549). */
13194 {
13198 {
13203 {
13207 {
13210 }
13211 else
13212 {
13215 }
13217 }
13218 }
13219 else
13220 {
13226 else
13227 {
13230 }
13231 }
13232 }
13233 else
13234 {
13237 }
13242 {
13245 tree spec;
13247 tree ctx;
13256 {
13257 /* If this is the canonical decl, we don't have to
13258 mess with instantiations, and often we can't (for
13259 typename, template type parms and such). Note that
13260 TYPE_NAME is not correct for the above test if
13261 we've copied the type for a typedef. */
13267 }
13269 /* Check to see if we already have the specialization we
13270 need. */
13273 {
13274 /* T is a static data member or namespace-scope entity.
13275 We have to substitute into namespace-scope variables
13276 (not just variable templates) because of cases like:
13278 template <class T> void f() { extern T t; }
13280 where the entity referenced is not known until
13281 instantiation time. */
13285 {
13287 complain,
13289 /* If CTX is unchanged, then T is in fact the
13290 specialization we want. That situation occurs when
13291 referencing a static data member within in its own
13292 class. We can use pointer equality, rather than
13293 same_type_p, because DECL_CONTEXT is always
13294 canonical... */
13296 /* ... unless T is a member template; in which
13297 case our caller can be willing to create a
13298 specialization of that template represented
13299 by T. */
13303 }
13306 {
13311 argvec = (coerce_innermost_template_parms
13319 }
13320 }
13321 else
13322 {
13323 /* A local variable. */
13325 /* Subsequent calls to pushdecl will fill this in. */
13327 /* Unless this is a reference to a static variable from an
13328 enclosing function, in which case we need to fill it in now. */
13330 {
13334 }
13336 }
13337 /* If we already have the specialization we need, there is
13338 nothing more to do. */
13340 {
13343 }
13345 /* Create a new node for the specialization we need. */
13348 {
13351 else
13359 {
13360 /* Mask off any template args past the variable's context so we
13361 don't replace the auto with an unrelated argument. */
13365 /* This should never happen with the new lambda instantiation
13366 model, but keep the handling just in case. */
13369 }
13371 }
13373 {
13374 /* Even if the original location is out of scope, the
13375 newly substituted one is not. */
13382 {
13383 /* It may seem that this case cannot occur, since:
13385 typedef void f();
13386 void g() { f x; }
13388 declares a function, not a variable. However:
13390 typedef void f();
13391 template <typename T> void g() { T t; }
13392 template void g<f>();
13394 is an attempt to declare a variable with function
13395 type. */
13397 /* R is not yet sufficiently initialized, so we
13398 just use its name. */
13401 }
13403 /* Wait until cp_finish_decl to set this again, to handle
13404 circular dependency (template/instantiate6.C). */
13409 {
13414 {
13417 }
13419 }
13423 }
13429 /* Clear out the mangled name and RTL for the instantiation. */
13433 /* The initializer must not be expanded until it is required;
13434 see [temp.inst]. */
13438 {
13444 /* Possibly limit visibility based on template args. */
13447 {
13451 }
13453 }
13456 {
13457 /* A static data member declaration is always marked
13458 external when it is declared in-class, even if an
13459 initializer is present. We mimic the non-template
13460 processing here. */
13468 }
13469 else
13470 {
13475 }
13483 /* Preserve a typedef that names a type. */
13485 {
13489 /* An alias template specialization can be dependent
13490 even if its underlying type is not. */
13492 }
13495 }
13500 }
13501 #undef RETURN
13503 out:
13504 /* Restore the file and line information. */
13508 }
13510 /* Substitute into the ARG_TYPES of a function type.
13511 If END is a TREE_CHAIN, leave it and any following types
13512 un-substituted. */
13514 static tree
13516 tree args,
13517 tree end,
13518 tsubst_flags_t complain,
13519 tree in_decl)
13520 {
13521 tree remaining_arg_types;
13525 tree default_arg;
13536 {
13537 /* For a pack expansion, perform substitution on the
13538 entire expression. Later on, we'll handle the arguments
13539 one-by-one. */
13544 /* So that we'll spin through the parameters, one by one. */
13546 else
13547 {
13548 /* We only partially substituted into the parameter
13549 pack. Our type is TYPE_PACK_EXPANSION. */
13552 }
13553 }
13566 {
13568 {
13572 }
13574 }
13575 /* DR 657. */
13579 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13580 top-level qualifiers as required. */
13583 /* We do not substitute into default arguments here. The standard
13584 mandates that they be instantiated only when needed, which is
13585 done in build_over_call. */
13588 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13589 since the new op() won't have any associated template arguments for us
13590 to refer to later. */
13596 {
13597 /* We've instantiated a template before its default arguments
13598 have been parsed. This can happen for a nested template
13599 class, and is not an error unless we require the default
13600 argument in a call of this function. */
13601 remaining_arg_types =
13604 }
13605 else
13606 remaining_arg_types =
13608 }
13611 }
13613 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13614 *not* handle the exception-specification for FNTYPE, because the
13615 initial substitution of explicitly provided template parameters
13616 during argument deduction forbids substitution into the
13617 exception-specification:
13619 [temp.deduct]
13621 All references in the function type of the function template to the
13622 corresponding template parameters are replaced by the specified tem-
13623 plate argument values. If a substitution in a template parameter or
13624 in the function type of the function template results in an invalid
13625 type, type deduction fails. [Note: The equivalent substitution in
13626 exception specifications is done only when the function is instanti-
13627 ated, at which point a program is ill-formed if the substitution
13628 results in an invalid type.] */
13630 static tree
13632 tree args,
13633 tsubst_flags_t complain,
13634 tree in_decl)
13635 {
13636 tree return_type;
13638 tree fntype;
13640 /* The TYPE_CONTEXT is not used for function/method types. */
13643 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13644 failure. */
13648 {
13649 /* Substitute the argument types. */
13661 {
13662 /* DR 1207: 'this' is in scope in the trailing return type. */
13664 }
13666 /* Substitute the return type. */
13670 {
13673 }
13674 }
13675 else
13676 /* Substitute the return type. */
13681 /* DR 486 clarifies that creation of a function type with an
13682 invalid return type is a deduction failure. */
13685 {
13687 {
13690 else
13692 }
13694 }
13695 /* And DR 657. */
13700 {
13701 /* Substitute the argument types. */
13706 }
13708 /* Construct a new type node and return it. */
13710 {
13715 }
13716 else
13717 {
13719 /* Don't pick up extra function qualifiers from the basetype. */
13722 {
13723 /* [temp.deduct]
13725 Type deduction may fail for any of the following
13726 reasons:
13728 -- Attempting to create "pointer to member of T" when T
13729 is not a class type. */
13732 r);
13734 }
13739 }
13746 }
13748 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13749 ARGS into that specification, and return the substituted
13750 specification. If there is no specification, return NULL_TREE. */
13752 static tree
13754 tree args,
13755 tsubst_flags_t complain,
13756 tree in_decl,
13758 {
13759 tree specs;
13760 tree new_specs;
13765 {
13766 /* A noexcept-specifier. */
13771 {
13772 /* Defer instantiation of noexcept-specifiers to avoid
13773 excessive instantiations (c++/49107). */
13776 {
13777 /* We already partially instantiated this member template,
13778 so combine the new args with the old. */
13783 }
13784 else
13785 {
13788 }
13789 }
13790 else
13791 new_specs = tsubst_copy_and_build
13795 }
13797 {
13800 else
13802 {
13803 tree spec;
13808 {
13809 /* Expand the pack expansion type. */
13812 in_decl);
13818 else
13819 {
13820 /* We're substituting into a member template, so
13821 we got a TYPE_PACK_EXPANSION back. Add that
13822 expansion and move on. */
13826 expanded_specs,
13827 complain);
13830 }
13831 }
13834 {
13837 else
13842 complain);
13843 }
13846 }
13847 }
13849 }
13851 /* Take the tree structure T and replace template parameters used
13852 therein with the argument vector ARGS. IN_DECL is an associated
13853 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13854 Issue error and warning messages under control of COMPLAIN. Note
13855 that we must be relatively non-tolerant of extensions here, in
13856 order to preserve conformance; if we allow substitutions that
13857 should not be allowed, we may allow argument deductions that should
13858 not succeed, and therefore report ambiguous overload situations
13859 where there are none. In theory, we could allow the substitution,
13860 but indicate that it should have failed, and allow our caller to
13861 make sure that the right thing happens, but we don't try to do this
13862 yet.
13864 This function is used for dealing with types, decls and the like;
13865 for expressions, use tsubst_expr or tsubst_copy. */
13867 tree
13869 {
13892 else
13897 /* Reuse typedefs. We need to do this to handle dependent attributes,
13898 such as attribute aligned. */
13901 {
13905 {
13906 /* DECL represents an alias template and we want to
13907 instantiate it. */
13911 }
13915 {
13919 }
13924 else
13925 /* The typedef is from a non-template context. */
13929 {
13931 r = cp_build_qualified_type_real
13935 }
13936 else
13937 {
13938 /* We don't have an instantiation yet, so drop the typedef. */
13943 }
13944 }
13961 {
13987 {
13993 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13994 needed. */
14000 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14001 with TREE_SIDE_EFFECTS that indicates this is not an integral
14002 constant expression. */
14005 {
14008 }
14011 }
14017 {
14023 /* Early in template argument deduction substitution, we don't
14024 want to reduce the level of 'auto', or it will be confused
14025 with a normal template parm in subsequent deduction. */
14037 {
14040 /* See through ARGUMENT_PACK_SELECT arguments. */
14043 }
14048 {
14050 /* If ARG is an argument pack, we don't actually want to
14051 perform a substitution here, because substitutions
14052 for argument packs are only done
14053 element-by-element. We can get to this point when
14054 substituting the type of a non-type template
14055 parameter pack, when that type actually contains
14056 template parameter packs from an outer template, e.g.,
14058 template<typename... Types> struct A {
14059 template<Types... Values> struct B { };
14060 }; */
14064 {
14070 return cp_build_qualified_type_real
14072 }
14074 {
14075 /* We are processing a type constructed from a
14076 template template parameter. */
14087 /* Consider this code:
14089 template <template <class> class Template>
14090 struct Internal {
14091 template <class Arg> using Bind = Template<Arg>;
14092 };
14094 template <template <class> class Template, class Arg>
14095 using Instantiate = Template<Arg>; //#0
14097 template <template <class> class Template,
14098 class Argument>
14099 using Bind =
14100 Instantiate<Internal<Template>::template Bind,
14101 Argument>; //#1
14103 When #1 is parsed, the
14104 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14105 parameter `Template' in #0 matches the
14106 UNBOUND_CLASS_TEMPLATE representing the argument
14107 `Internal<Template>::template Bind'; We then want
14108 to assemble the type `Bind<Argument>' that can't
14109 be fully created right now, because
14110 `Internal<Template>' not being complete, the Bind
14111 template cannot be looked up in that context. So
14112 we need to "store" `Bind<Argument>' for later
14113 when the context of Bind becomes complete. Let's
14114 store that in a TYPENAME_TYPE. */
14118 argvec),
14119 typename_type,
14120 complain);
14122 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14123 are resolving nested-types in the signature of a
14124 member function templates. Otherwise ARG is a
14125 TEMPLATE_DECL and is the real template to be
14126 instantiated. */
14134 complain);
14135 return cp_build_qualified_type_real
14137 }
14140 else
14141 /* TEMPLATE_PARM_INDEX. */
14143 }
14146 /* This can happen during the attempted tsubst'ing in
14147 unify. This means that we don't yet have any information
14148 about the template parameter in question. */
14151 /* If we get here, we must have been looking at a parm for a
14152 more deeply nested template. Make a new version of this
14153 template parameter, but with a lower level. */
14155 {
14160 {
14162 r = cp_build_qualified_type_real
14166 }
14173 /* Break infinite recursion when substituting the constraints
14175 else
14176 {
14187 {
14188 /* Propagate constraints on placeholders. */
14193 {
14196 }
14197 }
14200 /* We have reduced the level of the template
14201 template parameter, but not the levels of its
14202 template parameters, so canonical_type_parameter
14203 will not be able to find the canonical template
14204 template parameter for this level. Thus, we
14205 require structural equality checking to compare
14206 TEMPLATE_TEMPLATE_PARMs. */
14210 else
14214 {
14216 /* We might need to substitute into the types of non-type
14217 template parameters. */
14229 }
14230 }
14234 /* OK, now substitute the type of the non-type parameter. We
14235 couldn't do it earlier because it might be an auto parameter,
14236 and we wouldn't need to if we had an argument. */
14245 }
14248 }
14251 {
14259 {
14263 }
14266 {
14270 }
14273 {
14277 }
14283 }
14286 /* We should never be tsubsting a binfo. */
14290 /* A vector of template arguments. */
14296 {
14300 /* [temp.deduct]
14302 Type deduction may fail for any of the following
14303 reasons:
14305 -- Attempting to create a pointer to reference type.
14306 -- Attempting to create a reference to a reference type or
14307 a reference to void.
14309 Core issue 106 says that creating a reference to a reference
14310 during instantiation is no longer a cause for failure. We
14311 only enforce this check in strict C++98 mode. */
14315 {
14318 /* We keep track of the last time we issued this error
14319 message to avoid spewing a ton of messages during a
14320 single bad template instantiation. */
14323 {
14328 else
14331 }
14334 }
14338 {
14340 {
14343 type);
14344 else
14346 type);
14347 }
14349 }
14351 {
14355 }
14357 /* In C++0x, during template argument substitution, when there is an
14358 attempt to create a reference to a reference type, reference
14359 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14361 "If a template-argument for a template-parameter T names a type
14362 that is a reference to a type A, an attempt to create the type
14363 'lvalue reference to cv T' creates the type 'lvalue reference to
14364 A,' while an attempt to create the type type rvalue reference to
14365 cv T' creates the type T"
14366 */
14367 r = cp_build_reference_type
14370 else
14375 /* Will this ever be needed for TYPE_..._TO values? */
14379 }
14381 {
14384 {
14385 /* [temp.deduct]
14387 Type deduction may fail for any of the following
14388 reasons:
14390 -- Attempting to create "pointer to member of T" when T
14391 is not a class type. */
14395 }
14397 {
14401 }
14403 {
14407 }
14410 {
14411 /* The type of the implicit object parameter gets its
14412 cv-qualifiers from the FUNCTION_TYPE. */
14413 tree memptr;
14414 tree method_type
14419 complain);
14420 }
14421 else
14424 complain);
14425 }
14428 {
14429 tree fntype;
14430 tree specs;
14435 /* Substitute the exception specification. */
14443 }
14445 {
14450 /* As an optimization, we avoid regenerating the array type if
14451 it will obviously be the same as T. */
14455 /* These checks should match the ones in create_array_type_for_decl.
14457 [temp.deduct]
14459 The deduction may fail for any of the following reasons:
14461 -- Attempting to create an array with an element type that
14462 is void, a function type, or a reference type, or [DR337]
14463 an abstract class type. */
14469 {
14473 }
14481 {
14484 }
14487 }
14490 {
14502 {
14506 }
14508 {
14509 /* Normally, make_typename_type does not require that the CTX
14510 have complete type in order to allow things like:
14512 template <class T> struct S { typename S<T>::X Y; };
14514 But, such constructs have already been resolved by this
14515 point, so here CTX really should have complete type, unless
14516 it's a partial instantiation. */
14519 {
14523 }
14524 }
14531 {
14534 }
14537 {
14539 {
14543 else
14545 }
14547 {
14551 else
14553 }
14554 }
14556 return cp_build_qualified_type_real
14558 }
14561 {
14573 }
14576 {
14577 tree type;
14593 complain);
14594 }
14597 {
14598 tree type;
14609 {
14611 {
14615 }
14618 }
14629 else
14630 {
14634 /* In a template ~id could be either a complement expression
14635 or an unqualified-id naming a destructor; if instantiating
14636 it produces an expression, it's not an id-expression or
14637 member access. */
14640 }
14645 }
14648 {
14652 }
14656 {
14657 tree r;
14661 else
14669 }
14684 /* We should use one of the expression tsubsts for these codes. */
14690 }
14691 }
14693 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14694 expression on the left-hand side of the "." or "->" operator. We
14695 only do the lookup if we had a dependent BASELINK. Otherwise we
14696 adjust it onto the instantiated heirarchy. */
14698 static tree
14701 {
14713 {
14720 }
14727 {
14733 /* Treat as-if non-dependent below. */
14738 {
14744 }
14748 }
14749 else
14750 /* We're going to overwrite pieces below, make a duplicate. */
14753 /* If lookup found a single function, mark it as used at this point.
14754 (If lookup found multiple functions the one selected later by
14755 overload resolution will be marked as used at that point.) */
14757 {
14763 /* We might have instantiated an auto function. */
14765 }
14768 {
14769 /* Add back the template arguments, if present. */
14774 /* Update the conversion operator type. */
14776 }
14782 {
14784 qualifying_scope,
14785 object_type);
14787 /* We need to call adjust_result_of_qualified_name_lookup in case the
14788 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14789 so that we still get virtual function binding. */
14791 }
14794 }
14796 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14797 true if the qualified-id will be a postfix-expression in-and-of
14798 itself; false if more of the postfix-expression follows the
14799 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14800 of "&". */
14802 static tree
14806 {
14807 tree expr;
14808 tree scope;
14809 tree name;
14811 tree template_args;
14816 /* Figure out what name to look up. */
14819 {
14829 }
14830 else
14831 {
14834 }
14836 /* Substitute into the qualifying scope. When there are no ARGS, we
14837 are just trying to simplify a non-dependent expression. In that
14838 case the qualifying scope may be dependent, and, in any case,
14839 substituting will not help. */
14842 {
14845 }
14846 else
14850 {
14857 }
14860 {
14862 {
14863 /* A BIT_NOT_EXPR is used to represent a destructor. */
14865 {
14869 }
14870 else
14873 }
14874 else
14878 {
14880 {
14884 }
14886 }
14887 }
14890 {
14892 scope);
14893 /* Remember that there was a reference to this entity. */
14896 }
14899 {
14905 }
14908 {
14911 complain);
14912 else
14914 }
14920 {
14921 expr = (adjust_result_of_qualified_name_lookup
14923 expr = (finish_qualified_id_expr
14927 }
14929 /* Expressions do not generally have reference type. */
14931 /* However, if we're about to form a pointer-to-member, we just
14932 want the referenced member referenced. */
14940 }
14942 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14943 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14944 for tsubst. */
14946 static tree
14949 {
14956 {
14957 /* If we had an initializer but it
14958 instantiated to nothing,
14959 value-initialize the object. This will
14960 only occur when the initializer was a
14961 pack expansion where the parameter packs
14962 used in that expansion were of length
14963 zero. */
14965 complain);
14970 }
14973 }
14975 /* Like tsubst, but deals with expressions. This function just replaces
14976 template parms; to finish processing the resultant expression, use
14977 tsubst_copy_and_build or tsubst_expr. */
14979 static tree
14981 {
14983 tree r;
14991 {
14996 {
14997 /* We get here for a use of 'this' in an NSDMI. */
15001 /* This can happen for a parameter name used later in a function
15002 declaration (such as in a late-specified return type). Just
15003 make a dummy decl, since it's only used for its type. */
15006 /* Give it the template pattern as its context; its true context
15007 hasn't been instantiated yet and this is good enough for
15008 mangling. */
15010 }
15019 {
15020 tree enum_type;
15021 tree v;
15025 /* There is no need to substitute into namespace-scope
15026 enumerators. */
15029 /* If ARGS is NULL, then T is known to be non-dependent. */
15033 /* Unfortunately, we cannot just call lookup_name here.
15034 Consider:
15036 template <int I> int f() {
15037 enum E { a = I };
15038 struct S { void g() { E e = a; } };
15039 };
15041 When we instantiate f<7>::S::g(), say, lookup_name is not
15042 clever enough to find f<7>::a. */
15043 enum_type
15053 /* We didn't find the name. That should never happen; if
15054 name-lookup found it during preliminary parsing, we
15055 should find it again here during instantiation. */
15057 }
15062 {
15063 tree ctx;
15068 {
15071 {
15075 }
15077 }
15078 }
15088 {
15091 {
15092 /* First try name lookup to find the instantiation. */
15095 {
15096 /* Make sure that the one we found is the one we want. */
15100 }
15104 else
15105 {
15106 /* This can happen for a variable used in a
15107 late-specified return type of a local lambda, or for a
15108 local static or constant. Building a new VAR_DECL
15109 should be OK in all those cases. */
15112 /* Avoid infinite recursion (79640). */
15115 {
15116 /* We can't call cp_finish_decl, so handle the
15117 initializer by hand. */
15132 }
15139 }
15140 /* Remember this for subsequent uses. */
15143 }
15146 }
15147 else
15157 /* An OVERLOAD will always be a non-dependent overload set; an
15158 overload set from function scope will just be represented with an
15159 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15161 /* We must have marked any lookups as persistent. */
15177 {
15178 /* Template template argument like the following example need
15179 special treatment:
15181 template <template <class> class TT> struct C {};
15182 template <class T> struct D {
15183 template <class U> struct E {};
15184 C<E> c; // #1
15185 };
15186 D<int> d; // #2
15188 We are processing the template argument `E' in #1 for
15189 the template instantiation #2. Originally, `E' is a
15190 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15191 have to substitute this with one having context `D<int>'. */
15195 {
15196 /* When rewriting a constructor into a deduction guide, a
15197 non-dependent name can become dependent, so memtmpl<args>
15198 becomes context::template memtmpl<args>. */
15202 }
15204 }
15205 else
15206 /* Ordinary template template argument. */
15211 {
15212 /* Handle location wrappers by substituting the wrapped node
15213 first, *then* reusing the resulting type. Doing the type
15214 first ensures that we handle template parameters and
15215 parameter pack expansions. */
15219 }
15229 {
15233 }
15238 {
15247 /* We only want to compute the number of arguments. */
15250 else
15257 {
15259 /* Set TREE_USED for the benefit of -Wunused. */
15263 }
15271 {
15276 else
15282 else
15285 }
15286 else
15288 }
15290 {
15298 }
15299 /* Fall through */
15315 {
15319 }
15322 {
15323 tree object;
15324 tree name;
15329 {
15333 }
15336 {
15346 }
15351 in_decl);
15352 else
15355 }
15393 {
15397 }
15400 {
15405 }
15408 {
15412 }
15415 {
15423 }
15429 {
15436 }
15439 {
15446 }
15449 {
15456 }
15459 {
15460 /* Substituted template arguments */
15469 }
15472 {
15492 }
15517 /* Fall through. */
15520 {
15523 }
15524 else
15528 /* This is handled by tsubst_copy_and_build. */
15532 {
15536 }
15539 /* We shouldn't have built any of these during initial template
15540 generation. Instead, they should be built during instantiation
15541 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15545 {
15555 }
15573 {
15574 /* Instantiate any typedefs in the type. */
15579 }
15582 /* These can sometimes show up in a partial instantiation, but never
15583 involve template parms. */
15599 /* ??? There's no point in copying it for now, but maybe some
15600 day it will contain more information, such as a pointer back
15601 to the containing function, inlined copy or so. */
15605 /* We shouldn't get here, but keep going if !flag_checking. */
15609 }
15610 }
15612 /* Helper function for tsubst_omp_clauses, used for instantiation of
15613 OMP_CLAUSE_DECL of clauses. */
15615 static tree
15617 tree in_decl)
15618 {
15622 /* Handle an OpenMP array section represented as a TREE_LIST (or
15623 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15624 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15625 TREE_LIST. We can handle it exactly the same as an array section
15626 (purpose, value, and a chain), even though the nomenclature
15627 (low_bound, length, etc) is different. */
15629 {
15630 tree low_bound
15636 in_decl);
15645 }
15648 /* Undo convert_from_reference tsubst_expr could have called. */
15654 }
15656 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15658 static tree
15661 {
15666 {
15672 {
15675 {
15681 }
15682 /* FALLTHRU */
15697 in_decl);
15729 {
15732 {
15739 }
15740 else
15742 }
15745 in_decl);
15751 in_decl);
15759 in_decl);
15761 {
15764 }
15769 else
15772 in_decl,
15796 }
15799 {
15809 /* tsubst_expr on SCOPE_REF results in returning
15810 finish_non_static_data_member result. Undo that here. */
15814 {
15819 {
15823 CASE_CONVERT:
15832 /* FALLTHRU */
15836 }
15837 }
15843 {
15846 {
15849 }
15850 }
15854 }
15855 }
15859 {
15864 {
15867 }
15868 }
15870 }
15872 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15874 static tree
15876 tree in_decl)
15877 {
15878 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15898 {
15901 else
15902 {
15906 }
15907 }
15912 #undef RECUR
15913 }
15915 /* Used to temporarily communicate the list of #pragma omp parallel
15916 clauses to #pragma omp for instantiation if they are combined
15917 together. */
15921 /* Substitute one OMP_FOR iterator. */
15923 static void
15928 {
15929 #define RECUR(NODE) \
15930 tsubst_expr ((NODE), args, complain, in_decl, \
15931 integral_constant_expression_p)
15938 {
15941 }
15947 {
15948 /* We need to jump through some hoops to handle declarations in the
15949 init-statement, since we might need to handle auto deduction,
15950 but we need to keep control of initialization. */
15954 }
15955 else
15956 {
15958 {
15961 {
15965 {
15969 CASE_CONVERT:
15977 {
15980 }
15981 /* FALLTHRU */
15985 }
15986 }
15987 }
15988 else
15990 }
16001 {
16003 {
16004 /* Declare the variable, but don't let that initialize it. */
16009 }
16014 {
16019 }
16020 else
16027 }
16030 {
16031 /* Declare and initialize the variable. */
16034 }
16036 {
16040 {
16042 {
16048 {
16051 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16056 }
16059 {
16061 decl);
16063 }
16066 {
16068 decl);
16070 }
16071 else
16073 }
16076 }
16078 {
16083 {
16086 }
16087 }
16088 }
16091 {
16095 }
16096 else
16100 {
16111 {
16119 }
16120 else
16126 {
16132 }
16136 {
16144 }
16145 else
16151 }
16157 #undef RECUR
16158 }
16160 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16161 of OMP_TARGET's body. */
16163 static tree
16165 {
16168 {
16177 }
16179 }
16181 /* Helper function for tsubst_expr. For decomposition declaration
16182 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16183 also the corresponding decls representing the identifiers
16184 of the decomposition declaration. Return DECL if successful
16185 or error_mark_node otherwise, set *FIRST to the first decl
16186 in the list chained through DECL_CHAIN and *CNT to the number
16187 of such decls. */
16189 static tree
16193 {
16198 decl2
16203 {
16205 {
16208 }
16225 {
16228 }
16229 else
16231 }
16234 }
16236 /* Like tsubst_copy for expressions, etc. but also does semantic
16237 processing. */
16239 tree
16242 {
16243 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16244 #define RECUR(NODE) \
16245 tsubst_expr ((NODE), args, complain, in_decl, \
16246 integral_constant_expression_p)
16249 tree r;
16250 location_t loc;
16262 {
16264 {
16265 tree_stmt_iterator i;
16269 }
16284 else
16294 {
16296 tree init;
16302 {
16312 else
16314 }
16317 {
16318 /* We're in tsubst_lambda_expr, we've already inserted a new
16319 capture proxy, so look it up and register it. */
16320 tree inst;
16322 {
16323 inst = (retrieve_local_specialization
16326 }
16327 else
16328 {
16332 }
16335 }
16338 /* Don't copy the old closure; we'll create a new one in
16339 tsubst_lambda_expr. */
16341 else
16342 {
16346 {
16347 /* By marking the declaration as instantiated, we avoid
16348 trying to instantiate it. Since instantiate_decl can't
16349 handle local variables, and since we've already done
16350 all that needs to be done, that's the right thing to
16351 do. */
16356 /* Anonymous aggregates are a special case. */
16359 {
16362 {
16366 }
16368 }
16374 {
16379 }
16380 else
16381 {
16386 {
16387 /* For __PRETTY_FUNCTION__ we have to adjust the
16388 initializer. */
16392 }
16393 else
16397 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16402 {
16404 tree first;
16405 tree ndecl
16413 }
16414 else
16416 }
16417 }
16418 }
16421 }
16431 {
16435 }
16440 {
16441 /* Construct another range_for, if this is not a final
16442 substitution (for inside inside a generic lambda of a
16443 template). Otherwise convert to a regular for. */
16445 stmt = (processing_template_decl
16461 {
16465 }
16466 else
16467 {
16473 }
16479 }
16486 {
16490 }
16496 {
16500 }
16515 {
16516 /* We're partially instantiating a generic lambda, but the condition
16517 of the constexpr if is still dependent. Don't substitute into the
16518 branches now, just remember the template arguments. */
16526 }
16529 else
16530 {
16537 }
16543 {
16552 }
16560 else
16568 else
16589 {
16596 }
16600 {
16602 tree label;
16609 }
16615 /* Computed goto's must be tsubst'd into. On the other hand,
16616 non-computed gotos must not be; the identifier in question
16617 will have no binding. */
16619 else
16625 {
16641 }
16646 {
16651 }
16652 else
16653 {
16658 else
16665 else
16671 else
16673 }
16677 {
16681 {
16683 /* Prevent instantiate_decl from trying to instantiate
16684 this variable. We've already done all that needs to be
16685 done. */
16688 }
16693 }
16699 {
16700 /* Local classes are not independent templates; they are
16701 instantiated along with their containing function. And this
16702 way we don't have to deal with pushing out of one local class
16703 to instantiate a member of another local class. */
16704 /* Closures are handled by the LAMBDA_EXPR. */
16714 }
16718 {
16719 tree condition;
16722 condition =
16724 args,
16733 }
16739 in_decl);
16774 {
16787 in_decl);
16789 {
16796 }
16808 integral_constant_expression_p);
16819 else
16820 {
16828 }
16832 }
16837 /* FALLTHRU */
16844 in_decl);
16861 in_decl);
16872 {
16875 {
16876 /* For combined target teams, ensure the num_teams and
16877 thread_limit clause expressions are evaluated on the host,
16878 before entering the target construct. */
16879 tree c;
16885 {
16894 OMP_CLAUSE_FIRSTPRIVATE);
16898 }
16899 }
16900 }
16960 {
16965 {
16968 }
16974 }
16975 else
16976 {
16983 {
16986 }
16989 {
16994 {
16997 }
17003 }
17004 else
17005 {
17009 }
17012 }
17016 {
17022 {
17026 {
17031 }
17035 }
17036 else
17037 {
17042 }
17043 }
17047 {
17051 }
17064 /* If the first operand was a statement, we're done with it. */
17068 complain));
17082 integral_constant_expression_p));
17083 }
17086 out:
17089 #undef RECUR
17090 #undef RETURN
17091 }
17093 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17094 function. For description of the body see comment above
17095 cp_parser_omp_declare_reduction_exprs. */
17097 static void
17099 {
17105 tree_stmt_iterator tsi;
17116 {
17135 }
17137 {
17157 }
17158 }
17160 /* T is a postfix-expression that is not being used in a function
17161 call. Return the substituted version of T. */
17163 static tree
17165 tsubst_flags_t complain,
17166 tree in_decl)
17167 {
17171 else
17177 }
17179 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17180 instantiation context. Instantiating a pack expansion containing a lambda
17181 might result in multiple lambdas all based on the same lambda in the
17182 template. */
17184 tree
17186 {
17200 else
17208 {
17220 else
17225 {
17234 }
17235 else
17236 {
17242 }
17243 }
17247 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17265 else
17266 {
17267 /* Fix the type of 'this'. */
17273 {
17277 }
17278 else
17279 {
17283 }
17285 /* Let finish_function set this. */
17291 else
17292 /* Still increment function_depth so that we don't GC in the
17293 middle of an expression. */
17309 else
17312 /* The capture list was built up in reverse order; fix that now. */
17319 }
17326 }
17328 /* Like tsubst but deals with expressions and performs semantic
17329 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17331 tree
17333 tree args,
17334 tsubst_flags_t complain,
17335 tree in_decl,
17338 {
17339 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17340 #define RECUR(NODE) \
17341 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17343 integral_constant_expression_p)
17346 location_t loc;
17355 /* N3276 decltype magic only applies to calls at the top level or on the
17356 right side of a comma. */
17361 {
17364 /* Fall through. */
17366 {
17367 tree decl;
17368 cp_id_kind idk;
17373 {
17376 }
17378 /* Look up the name. */
17381 /* By convention, expressions use ERROR_MARK_NODE to indicate
17382 failure, not NULL_TREE. */
17388 integral_constant_expression_p,
17396 input_location);
17400 {
17404 }
17406 }
17409 {
17410 tree object;
17420 {
17425 }
17431 {
17434 }
17435 else
17442 else
17444 }
17447 {
17451 {
17452 /* A type conversion to reference type will be enclosed in
17453 such an indirect ref, but the substitution of the cast
17454 will have also added such an indirect ref. */
17456 }
17457 else
17465 }
17468 {
17472 }
17475 {
17479 {
17484 }
17486 /* We'll pass this to convert_nontype_argument again, we don't need
17487 to actually perform any conversion here. */
17493 flags));
17494 }
17497 {
17503 }
17510 {
17511 tree type;
17517 {
17522 }
17529 {
17547 }
17550 }
17583 else
17585 in_decl);
17620 {
17627 tree r = build_x_binary_op
17629 op0,
17631 ? ERROR_MARK
17633 op1,
17635 ? ERROR_MARK
17643 }
17646 {
17650 }
17666 /* Fall through */
17669 {
17670 tree r;
17676 {
17677 /* When there are no ARGS, we are trying to evaluate a
17678 non-dependent expression from the parser. Trying to do
17679 the substitutions may not work. */
17682 }
17683 else
17684 {
17689 else
17692 /*integral_constant_expression_p=*/
17696 }
17700 else
17704 {
17706 {
17708 {
17712 }
17713 else
17717 }
17719 }
17721 }
17724 {
17734 }
17750 {
17754 tree r = build_x_modify_expr
17757 /* TREE_NO_WARNING must be set if either the expression was
17758 parenthesized or it uses an operator such as >>= rather
17759 than plain assignment. In the former case, it was already
17760 set and must be copied. In the latter case,
17761 build_x_modify_expr sets it and it must not be reset
17762 here. */
17767 }
17772 /* Remember that there was a reference to this entity. */
17779 {
17784 tree ret;
17788 else
17789 {
17793 }
17795 /* If there was an initializer in the original tree, but it
17796 instantiated to an empty list, then we should pass a
17797 non-NULL empty vector to tell build_new that it was an
17798 empty initializer() rather than no initializer. This can
17799 only happen when the initializer is a pack expansion whose
17800 parameter packs are of length zero. */
17803 else
17804 {
17808 else
17809 {
17812 }
17813 }
17819 complain);
17827 }
17830 {
17836 complain));
17837 }
17840 {
17844 integral_constant_expression_p);
17846 op0,
17849 }
17852 {
17853 tree function;
17858 tree ret;
17861 /* Internal function with no arguments. */
17865 /* When we parsed the expression, we determined whether or
17866 not Koenig lookup should be performed. */
17869 {
17872 }
17874 {
17879 }
17881 {
17882 /* Do nothing; calling tsubst_copy_and_build on an identifier
17883 would incorrectly perform unqualified lookup again.
17885 Note that we can also have an IDENTIFIER_NODE if the earlier
17886 unqualified lookup found a member function; in that case
17887 koenig_p will be false and we do want to do the lookup
17888 again to find the instantiated member function.
17890 FIXME but doing that causes c++/15272, so we need to stop
17891 using IDENTIFIER_NODE in that situation. */
17893 }
17894 else
17895 {
17897 {
17903 }
17904 else
17909 /* Avoid error about taking the address of a constructor. */
17913 in_decl,
17915 integral_constant_expression_p);
17919 }
17924 {
17929 else
17930 {
17931 /* Expand the pack expansion and push each entry onto
17932 CALL_ARGS. */
17935 {
17940 {
17945 }
17946 }
17947 else
17948 {
17949 /* A partial substitution. Add one entry. */
17951 }
17952 }
17953 }
17955 /* We do not perform argument-dependent lookup if normal
17956 lookup finds a non-function, in accordance with the
17957 expected resolution of DR 218. */
17960 /* If lookup found a member function, the Koenig lookup is
17961 not appropriate, even if an unqualified-name was used
17962 to denote the function. */
17965 /* Only do this when substitution turns a dependent call
17966 into a non-dependent call. */
17974 {
17976 {
17977 /* For backwards compatibility and good diagnostics, try
17978 the unqualified lookup again if we aren't in SFINAE
17979 context. */
17980 tree unq = (tsubst_copy_and_build
17982 integral_constant_expression_p));
17984 {
17987 }
17990 {
17991 /* In a lambda fn, we have to be careful to not
17992 introduce new this captures. Legacy code can't
17993 be using lambdas anyway, so it's ok to be
17994 stricter. */
17999 "and no declarations were found by "
18000 "argument-dependent lookup at the point "
18007 else
18011 {
18022 {
18024 input_location);
18026 "declarations in dependent base %qT are "
18032 else
18036 }
18037 else
18039 "%qD declared here, later in the "
18042 {
18045 }
18046 }
18049 }
18050 }
18052 {
18057 }
18058 }
18060 /* Remember that there was a reference to this entity. */
18064 {
18067 }
18069 /* Put back tf_decltype for the actual call. */
18074 {
18078 {
18080 "wrong number of arguments to "
18083 }
18084 else
18086 input_location),
18091 /* Unsupported internal function with arguments. */
18093 }
18096 complain);
18098 {
18113 complain);
18114 else
18115 ret = (build_new_method_call
18120 complain));
18121 }
18122 else
18125 koenig_p,
18126 complain);
18131 {
18137 {
18143 {
18146 else
18148 /* The thunk location is not interesting. */
18150 }
18151 }
18152 }
18155 }
18158 {
18164 {
18166 {
18171 }
18172 else
18173 {
18178 }
18180 }
18181 else
18182 {
18185 }
18190 }
18193 {
18198 input_location));
18199 }
18202 {
18210 {
18211 /* We have pack expansions, so expand those and
18212 create a new list out of it. */
18215 tree chain;
18218 /* Expand the argument expressions. */
18226 /* Build the rest of the list. */
18231 /* Determine the number of arguments. */
18233 {
18236 }
18239 else
18240 {
18241 /* Since we only performed a partial substitution into
18242 the argument pack, we only RETURN (a single list
18243 node. */
18250 }
18252 /* Convert the argument vectors into a TREE_LIST */
18255 {
18256 /* Grab the Ith values. */
18257 i--;
18260 value
18264 /* Build the list (backwards). */
18266 }
18269 }
18285 }
18288 {
18289 tree object;
18290 tree object_type;
18291 tree member;
18292 tree r;
18296 /* Remember that there was a reference to this entity. */
18307 else
18313 {
18318 }
18322 {
18324 {
18329 {
18332 }
18334 {
18339 }
18340 }
18341 }
18344 {
18345 /* Lookup the template functions now that we know what the
18346 scope is. */
18354 {
18357 args);
18358 member = (adjust_result_of_qualified_name_lookup
18360 object_type));
18361 }
18362 else
18363 {
18365 input_location);
18367 }
18368 }
18372 {
18374 {
18378 else
18381 }
18383 }
18387 complain);
18391 }
18398 {
18406 tree r;
18411 /* We do not want to process the index of aggregate
18412 initializers as they are identifier nodes which will be
18413 looked up by digest_init. */
18419 {
18421 /* An identifier index is looked up in the type
18422 being initialized, not the current scope. */
18427 {
18428 /* Substitute into the pack expansion. */
18430 in_decl);
18434 ;
18436 /* Just move the argument into place. */
18438 else
18439 {
18440 /* Update the length of the final CONSTRUCTOR
18441 arguments vector, and note that we will need to
18442 copy.*/
18445 }
18446 }
18447 else
18449 }
18452 {
18457 {
18459 {
18464 }
18465 else
18467 }
18468 }
18474 {
18479 }
18483 }
18486 {
18489 {
18492 }
18493 else
18494 {
18497 }
18498 }
18503 /* Fall through */
18506 {
18508 /* ??? We're doing a subset of finish_id_expression here. */
18510 && !processing_template_decl
18511 && !cp_unevaluated_operand
18514 {
18516 /* Replace an evaluated use of the thread_local variable with
18517 a call to its wrapper. */
18519 }
18524 /* If the original type was a reference, we'll be wrapped in
18525 the appropriate INDIRECT_REF. */
18528 }
18531 {
18535 }
18538 {
18539 tree object_ptr
18546 }
18553 {
18564 }
18567 {
18573 integral_constant_expression_p);
18577 /* If the resulting list of expression statement is empty,
18578 fold it further into void_node. */
18583 }
18586 {
18590 }
18593 /* We can get here for a constant initializer of non-dependent type.
18594 FIXME stop folding in cp_parser_initializer_clause. */
18595 {
18597 complain);
18599 }
18603 integral_constant_expression_p));
18609 {
18614 complain));
18615 }
18622 /* We should only see these for location wrapper nodes, or within
18623 instantiate_non_dependent_expr (when args is NULL_TREE). */
18628 /* fallthrough. */
18631 /* Handle Objective-C++ constructs, if appropriate. */
18632 {
18633 tree subst
18638 }
18640 }
18642 #undef RECUR
18643 #undef RETURN
18644 out:
18647 }
18649 /* Verify that the instantiated ARGS are valid. For type arguments,
18650 make sure that the type's linkage is ok. For non-type arguments,
18651 make sure they are constants if they are integral or enumerations.
18652 Emit an error under control of COMPLAIN, and return TRUE on error. */
18654 static bool
18656 {
18660 {
18670 }
18672 {
18673 /* [basic.link]: A name with no linkage (notably, the name
18674 of a class or enumeration declared in a local scope)
18675 shall not be used to declare an entity with linkage.
18676 This implies that names with no linkage cannot be used as
18677 template arguments
18679 DR 757 relaxes this restriction for C++0x. */
18684 {
18685 /* DR 488 makes use of a type with no linkage cause
18686 type deduction to fail. */
18688 {
18691 else
18694 }
18696 }
18697 /* In order to avoid all sorts of complications, we do not
18698 allow variably-modified types as template arguments. */
18700 {
18704 }
18705 }
18706 /* Class template and alias template arguments should be OK. */
18708 ;
18709 /* A non-type argument of integral or enumerated type must be a
18710 constant. */
18715 {
18719 }
18721 }
18723 static bool
18725 {
18730 {
18733 }
18737 }
18739 /* We're out of SFINAE context now, so generate diagnostics for the access
18740 errors we saw earlier when instantiating D from TMPL and ARGS. */
18742 static void
18744 {
18756 }
18758 /* Instantiate the indicated variable, function, or alias template TMPL with
18759 the template arguments in TARG_PTR. */
18761 static tree
18763 {
18765 tree fndecl;
18766 tree gen_tmpl;
18767 tree spec;
18775 /* If this function is a clone, handle it specially. */
18777 {
18778 tree spec;
18779 tree clone;
18781 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18782 DECL_CLONED_FUNCTION. */
18788 /* Look for the clone. */
18792 /* We should always have found the clone by now. */
18795 }
18800 /* Check to see if we already have this specialization. */
18804 /* targ_ptr only has the innermost template args, so add the outer ones
18805 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18806 the case of a non-dependent call within a template definition). */
18807 targ_ptr = (add_outermost_template_args
18809 targ_ptr));
18811 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18812 but it doesn't seem to be on the hot path. */
18821 {
18823 {
18827 }
18829 }
18832 complain))
18835 /* We are building a FUNCTION_DECL, during which the access of its
18836 parameters and return types have to be checked. However this
18837 FUNCTION_DECL which is the desired context for access checking
18838 is not built yet. We solve this chicken-and-egg problem by
18839 deferring all checks until we have the FUNCTION_DECL. */
18842 /* Instantiation of the function happens in the context of the function
18843 template, not the context of the overload resolution we're doing. */
18845 /* If there are dependent arguments, e.g. because we're doing partial
18846 ordering, make sure processing_template_decl stays set. */
18850 {
18854 }
18860 {
18861 /* We need to determine if we're using a partial or explicit
18862 specialization now, because the type of the variable could be
18863 different. */
18869 {
18874 }
18875 }
18877 /* Substitute template parameters to obtain the specialization. */
18885 {
18888 }
18890 /* The DECL_TI_TEMPLATE should always be the immediate parent
18891 template, not the most general template. */
18895 /* Now we know the specialization, compute access previously
18896 deferred. Do no access control for inheriting constructors,
18897 as we already checked access for the inherited constructor. */
18900 {
18905 }
18908 /* If we've just instantiated the main entry point for a function,
18909 instantiate all the alternate entry points as well. We do this
18910 by cloning the instantiation of the main entry point, not by
18911 instantiating the template clones. */
18916 {
18918 {
18919 /* Remember to reinstantiate when we're out of SFINAE so the user
18920 can see the errors. */
18922 }
18924 }
18926 }
18928 /* Wrapper for instantiate_template_1. */
18930 tree
18932 {
18933 tree ret;
18938 }
18940 /* Instantiate the alias template TMPL with ARGS. Also push a template
18941 instantiation level, which instantiate_template doesn't do because
18942 functions and variables have sufficient context established by the
18943 callers. */
18945 static tree
18947 {
18954 {
18957 }
18959 args =
18967 /* We can't free this if a pending_template entry or last_error_tinst_level
18968 is pointing at it. */
18974 }
18976 /* PARM is a template parameter pack for FN. Returns true iff
18977 PARM is used in a deducible way in the argument list of FN. */
18979 static bool
18981 {
18984 {
18986 tree packs;
18992 {
18993 /* The template parameter pack is used in a function parameter
18994 pack. If this is the end of the parameter list, the
18995 template parameter pack is deducible. */
18998 else
18999 /* Otherwise, not. Well, it could be deduced from
19000 a non-pack parameter, but doing so would end up with
19001 a deduction mismatch, so don't bother. */
19003 }
19004 }
19005 /* The template parameter pack isn't used in any function parameter
19006 packs, but it might be used deeper, e.g. tuple<Args...>. */
19008 }
19010 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19011 NARGS elements of the arguments that are being used when calling
19012 it. TARGS is a vector into which the deduced template arguments
19013 are placed.
19015 Returns either a FUNCTION_DECL for the matching specialization of FN or
19016 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19017 true, diagnostics will be printed to explain why it failed.
19019 If FN is a conversion operator, or we are trying to produce a specific
19020 specialization, RETURN_TYPE is the return type desired.
19022 The EXPLICIT_TARGS are explicit template arguments provided via a
19023 template-id.
19025 The parameter STRICT is one of:
19027 DEDUCE_CALL:
19028 We are deducing arguments for a function call, as in
19029 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19030 deducing arguments for a call to the result of a conversion
19031 function template, as in [over.call.object].
19033 DEDUCE_CONV:
19034 We are deducing arguments for a conversion function, as in
19035 [temp.deduct.conv].
19037 DEDUCE_EXACT:
19038 We are deducing arguments when doing an explicit instantiation
19039 as in [temp.explicit], when determining an explicit specialization
19040 as in [temp.expl.spec], or when taking the address of a function
19041 template, as in [temp.deduct.funcaddr]. */
19043 tree
19045 tree explicit_targs,
19046 tree targs,
19049 tree return_type,
19050 unification_kind_t strict,
19054 {
19055 tree parms;
19056 tree fntype;
19069 tree tinst;
19075 full_targs = (add_outermost_template_args
19077 targs));
19082 /* In C++0x, it's possible to have a function template whose type depends
19083 on itself recursively. This is most obvious with decltype, but can also
19084 occur with enumeration scope (c++/48969). So we need to catch infinite
19085 recursion and reject the substitution at deduction time; this function
19086 will return error_mark_node for any repeated substitution.
19088 This also catches excessive recursion such as when f<N> depends on
19089 f<N-1> across all integers, and returns error_mark_node for all the
19090 substitutions back up to the initial one.
19092 This is, of course, not reentrant. */
19102 {
19103 /* [temp.deduct]
19105 The specified template arguments must match the template
19106 parameters in kind (i.e., type, nontype, template), and there
19107 must not be more arguments than there are parameters;
19108 otherwise type deduction fails.
19110 Nontype arguments must match the types of the corresponding
19111 nontype template parameters, or must be convertible to the
19112 types of the corresponding nontype parameters as specified in
19113 _temp.arg.nontype_, otherwise type deduction fails.
19115 All references in the function type of the function template
19116 to the corresponding template parameters are replaced by the
19117 specified template argument values. If a substitution in a
19118 template parameter or in the function type of the function
19119 template results in an invalid type, type deduction fails. */
19130 explicit_targs);
19132 /* Adjust any explicit template arguments before entering the
19133 substitution context. */
19134 explicit_targs
19136 complain,
19142 /* Substitute the explicit args into the function type. This is
19143 necessary so that, for instance, explicitly declared function
19144 arguments can match null pointed constants. If we were given
19145 an incomplete set of explicit args, we must not do semantic
19146 processing during substitution as we could create partial
19147 instantiations. */
19149 {
19154 /* Dig out the actual parm. */
19157 {
19160 }
19162 {
19165 }
19168 /* No explicit argument for this template parameter. */
19172 {
19173 /* Mark the argument pack as "incomplete". We could
19174 still deduce more arguments during unification.
19175 We remove this mark in type_unification_real. */
19177 {
19181 }
19183 /* We have some incomplete argument packs. */
19185 }
19186 }
19190 {
19193 }
19196 /* Ignore any access checks; we'll see them again in
19197 instantiate_template and they might have the wrong
19198 access path at this point. */
19210 /* Place the explicitly specified arguments in TARGS. */
19214 }
19216 /* Never do unification on the 'this' parameter. */
19220 {
19221 /* We're deducing for a call to the result of a template conversion
19222 function. The parms we really want are in return_type. */
19226 }
19228 {
19237 }
19239 /* We allow incomplete unification without an error message here
19240 because the standard doesn't seem to explicitly prohibit it. Our
19241 callers must be ready to deal with unification failures in any
19242 event. */
19245 /* If we aren't explaining yet, push tinst context so we can see where
19246 any errors (e.g. from class instantiations triggered by instantiation
19247 of default template arguments) come from. If we are explaining, this
19248 context is redundant. */
19250 {
19253 }
19255 /* type_unification_real will pass back any access checks from default
19256 template argument substitution. */
19268 /* Now that we have bindings for all of the template arguments,
19269 ensure that the arguments deduced for the template template
19270 parameters have compatible template parameter lists. We cannot
19271 check this property before we have deduced all template
19272 arguments, because the template parameter types of a template
19273 template parameter might depend on prior template parameters
19274 deduced after the template template parameter. The following
19275 ill-formed example illustrates this issue:
19277 template<typename T, template<T> class C> void f(C<5>, T);
19279 template<int N> struct X {};
19281 void g() {
19282 f(X<5>(), 5l); // error: template argument deduction fails
19283 }
19285 The template parameter list of 'C' depends on the template type
19286 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19287 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19288 time that we deduce 'C'. */
19291 {
19294 }
19296 /* All is well so far. Now, check:
19298 [temp.deduct]
19300 When all template arguments have been deduced, all uses of
19301 template parameters in nondeduced contexts are replaced with
19302 the corresponding deduced argument values. If the
19303 substitution results in an invalid type, as described above,
19304 type deduction fails. */
19307 {
19310 }
19312 /* Also collect access checks from the instantiation. */
19325 /* Now perform any access checks encountered during substitution. */
19332 /* If we're looking for an exact match, check that what we got
19333 is indeed an exact match. It might not be if some template
19334 parameters are used in non-deduced contexts. But don't check
19335 for an exact match if we have dependent template arguments;
19336 in that case we're doing partial ordering, and we already know
19337 that we have two candidates that will provide the actual type. */
19339 {
19343 tree sarg
19349 {
19353 }
19354 }
19356 /* After doing deduction with the inherited constructor, actually return an
19357 instantiation of the inheriting constructor. */
19363 fail:
19366 {
19368 /* Reset once we're all the way out. */
19370 }
19372 /* We can't free this if a pending_template entry or last_error_tinst_level
19373 is pointing at it. */
19379 }
19381 /* Adjust types before performing type deduction, as described in
19382 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19383 sections are symmetric. PARM is the type of a function parameter
19384 or the return type of the conversion function. ARG is the type of
19385 the argument passed to the call, or the type of the value
19386 initialized with the result of the conversion function.
19387 ARG_EXPR is the original argument expression, which may be null. */
19389 static int
19393 tree arg_expr)
19394 {
19398 {
19403 /* Swap PARM and ARG throughout the remainder of this
19404 function; the handling is precisely symmetric since PARM
19405 will initialize ARG rather than vice versa. */
19410 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19411 too, but here handle it by stripping the reference from PARM
19412 rather than by adding it to ARG. */
19420 /* Nothing else to do in this case. */
19425 }
19428 {
19429 /* [temp.deduct.call]
19431 If P is not a reference type:
19433 --If A is an array type, the pointer type produced by the
19434 array-to-pointer standard conversion (_conv.array_) is
19435 used in place of A for type deduction; otherwise,
19437 --If A is a function type, the pointer type produced by
19438 the function-to-pointer standard conversion
19439 (_conv.func_) is used in place of A for type deduction;
19440 otherwise,
19442 --If A is a cv-qualified type, the top level
19443 cv-qualifiers of A's type are ignored for type
19444 deduction. */
19449 else
19451 }
19453 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19454 reference to a cv-unqualified template parameter that does not represent a
19455 template parameter of a class template (during class template argument
19456 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19457 an lvalue, the type "lvalue reference to A" is used in place of A for type
19458 deduction. */
19465 /* try_one_overload doesn't provide an arg_expr, but
19466 functions are always lvalues. */
19470 /* [temp.deduct.call]
19472 If P is a cv-qualified type, the top level cv-qualifiers
19473 of P's type are ignored for type deduction. If P is a
19474 reference type, the type referred to by P is used for
19475 type deduction. */
19478 {
19481 }
19483 /* DR 322. For conversion deduction, remove a reference type on parm
19484 too (which has been swapped into ARG). */
19489 }
19491 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19492 template which does contain any deducible template parameters; check if
19493 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19494 unify_one_argument. */
19496 static int
19499 {
19500 tree type;
19504 else
19511 {
19515 }
19517 {
19522 }
19526 else
19528 }
19532 /* Returns true iff the expression EXPR is one from which a template
19533 argument can be deduced. In other words, if it's an undecorated
19534 use of a template non-type parameter. */
19536 static bool
19538 {
19539 /* Strip implicit conversions. */
19543 }
19545 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19546 deducible way; that is, if it has a max value of <PARM> - 1. */
19548 static bool
19550 {
19559 }
19561 /* Returns true iff the template arguments ARGS use a template parameter
19562 in a deducible way. */
19564 static bool
19566 {
19568 {
19573 else
19574 {
19581 else
19583 }
19586 }
19588 }
19590 /* Returns true iff TYPE contains any deducible references to template
19591 parameters, as per 14.8.2.5. */
19593 static bool
19595 {
19599 /* T
19600 cv-list T
19601 TT<T>
19602 TT<i>
19603 TT<> */
19608 /* T*
19609 T&
19610 T&& */
19614 /* T[integer-constant ]
19615 type [i] */
19620 /* T type ::*
19621 type T::*
19622 T T::*
19623 T (type ::*)()
19624 type (T::*)()
19625 type (type ::*)(T)
19626 type (T::*)(T)
19627 T (type ::*)(T)
19628 T (T::*)()
19629 T (T::*)(T) */
19632 || (uses_deducible_template_parms
19635 /* template-name <T> (where template-name refers to a class template)
19636 template-name <i> (where template-name refers to a class template) */
19643 /* type (T)
19644 T()
19645 T(T) */
19648 {
19657 }
19660 }
19662 /* Subroutine of type_unification_real and unify_pack_expansion to
19663 handle unification of a single P/A pair. Parameters are as
19664 for those functions. */
19666 static int
19670 {
19677 /* We can't deduce anything from this, but we might get all the
19678 template args from other function args. */
19681 /* Implicit conversions (Clause 4) will be performed on a function
19682 argument to convert it to the type of the corresponding function
19683 parameter if the parameter type contains no template-parameters that
19684 participate in template argument deduction. */
19687 /* For function parameters with no deducible template parameters,
19688 just return. We'll check non-dependent conversions later. */
19692 {
19694 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19695 | UNIFY_ALLOW_MORE_CV_QUAL
19709 }
19711 /* We only do these transformations if this is the top-level
19712 parameter_type_list in a call or declaration matching; in other
19713 situations (nested function declarators, template argument lists) we
19714 won't be comparing a type to an expression, and we don't do any type
19715 adjustments. */
19717 {
19719 {
19722 {
19723 /* [temp.deduct.type] A template-argument can be
19724 deduced from a pointer to function or pointer
19725 to member function argument if the set of
19726 overloaded functions does not contain function
19727 templates and at most one of a set of
19728 overloaded functions provides a unique
19729 match. */
19733 /* If a unique match was not found, this is a
19734 non-deduced context, so we still succeed. */
19736 }
19742 }
19744 arg_strict |=
19746 }
19747 else
19752 /* For deduction from an init-list we need the actual list. */
19756 }
19758 /* for_each_template_parm callback that always returns 0. */
19760 static int
19762 {
19764 }
19766 /* for_each_template_parm any_fn callback to handle deduction of a template
19767 type argument from the type of an array bound. */
19769 static int
19771 {
19779 {
19785 }
19787 /* Keep walking. */
19789 }
19791 /* Try to deduce any not-yet-deduced template type arguments from the type of
19792 an array bound. This is handled separately from unify because 14.8.2.5 says
19793 "The type of a type parameter is only deduced from an array bound if it is
19794 not otherwise deduced." */
19796 static void
19798 {
19803 }
19805 /* Most parms like fn_type_unification.
19807 If SUBR is 1, we're being called recursively (to unify the
19808 arguments of a function or method parameter of a function
19809 template).
19811 CHECKS is a pointer to a vector of access checks encountered while
19812 substituting default template arguments. */
19814 static int
19816 tree full_targs,
19817 tree xparms,
19821 unification_kind_t strict,
19825 {
19830 tree parms;
19841 /* Reset the number of non-defaulted template arguments contained
19842 in TARGS. */
19845 again:
19853 {
19858 /* For a function parameter pack that occurs at the end of the
19859 parameter-declaration-list, the type A of each remaining
19860 argument of the call is compared with the type P of the
19861 declarator-id of the function parameter pack. */
19867 /* For a function parameter pack that does not occur at the
19868 end of the parameter-declaration-list, the type of the
19869 parameter pack is a non-deduced context. */
19876 explain_p))
19878 }
19883 {
19884 /* Unify the remaining arguments with the pack expansion type. */
19885 tree argvec;
19888 /* Allocate a TREE_VEC and copy in all of the arguments */
19893 /* Copy the parameter into parmvec. */
19899 /* Advance to the end of the list of parameters. */
19901 }
19903 /* Fail if we've reached the end of the parm list, and more args
19904 are present, and the parm list isn't variadic. */
19907 /* Fail if parms are left and they don't have default values and
19908 they aren't all deduced as empty packs (c++/57397). This is
19909 consistent with sufficient_parms_p. */
19912 {
19916 do
19917 {
19920 count++;
19922 }
19926 type_pack_p);
19927 }
19930 {
19931 tsubst_flags_t complain = (explain_p
19932 ? tf_warning_or_error
19937 {
19941 /* Clear the "incomplete" flags on all argument packs now so that
19942 substituting them into later default arguments works. */
19944 {
19947 }
19955 {
19960 }
19962 /* If this is an undeduced nontype parameter that depends on
19963 a type parameter, try another pass; its type may have been
19964 deduced from a later argument than the one from which
19965 this parameter can be deduced. */
19969 {
19972 }
19974 /* Core issue #226 (C++0x) [temp.deduct]:
19976 If a template argument has not been deduced, its
19977 default template argument, if any, is used.
19979 When we are in C++98 mode, TREE_PURPOSE will either
19980 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19981 to explicitly check cxx_dialect here. */
19983 /* OK, there is a default argument. Wait until after the
19984 conversion check to do substitution. */
19987 /* If the type parameter is a parameter pack, then it will
19988 be deduced to an empty parameter pack. */
19990 {
19991 tree arg;
19994 {
19997 }
19998 else
20005 }
20008 }
20010 /* DR 1391: All parameters have args, now check non-dependent parms for
20011 convertibility. */
20015 {
20021 /* For a function parameter pack that occurs at the end of the
20022 parameter-declaration-list, the type A of each remaining
20023 argument of the call is compared with the type P of the
20024 declarator-id of the function parameter pack. */
20030 /* For a function parameter pack that does not occur at the
20031 end of the parameter-declaration-list, the type of the
20032 parameter pack is a non-deduced context. */
20041 explain_p))
20043 }
20045 /* Now substitute into the default template arguments. */
20047 {
20065 {
20066 /* The type of this non-type parameter depends on undeduced
20067 parameters. Don't try to use its default argument yet,
20068 but do check whether the arguments we already have cause
20069 substitution failure, so that that happens before we try
20070 later default arguments (78489). */
20072 NULL_TREE);
20075 else
20077 }
20078 else
20079 {
20087 else
20089 }
20100 {
20102 /* The position of the first default template argument,
20103 is also the number of non-defaulted arguments in TARGS.
20104 Record that. */
20107 }
20108 }
20112 }
20118 }
20120 /* Subroutine of type_unification_real. Args are like the variables
20121 at the call site. ARG is an overloaded function (or template-id);
20122 we try deducing template args from each of the overloads, and if
20123 only one succeeds, we go with that. Modifies TARGS and returns
20124 true on success. */
20126 static bool
20128 tree targs,
20129 tree parm,
20130 tree arg,
20131 unification_kind_t strict,
20134 {
20141 {
20144 }
20145 else
20149 /* Handle `&x' where `x' is some static or non-static member
20150 function name. */
20156 /* Strip baselink information. */
20161 {
20162 /* If we got some explicit template args, we need to plug them into
20163 the affected templates before we try to unify, in case the
20164 explicit args will completely resolve the templates in question. */
20171 {
20184 {
20189 {
20192 }
20193 }
20196 }
20197 /* If no templates (or more than one) are fully resolved by the
20198 explicit arguments, this template-id is a non-deduced context; it
20199 could still be OK if we deduce all template arguments for the
20200 enclosing call through other arguments. */
20203 }
20206 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20207 -- but the deduction does not succeed because the expression is
20208 not just the function on its own. */
20210 else
20212 {
20217 {
20220 }
20221 }
20223 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20224 to function or pointer to member function argument if the set of
20225 overloaded functions does not contain function templates and at most
20226 one of a set of overloaded functions provides a unique match.
20228 So if we found multiple possibilities, we return success but don't
20229 deduce anything. */
20232 {
20236 {
20241 /* Don't forget explicit template arguments in a pack. */
20245 }
20246 }
20251 }
20253 /* Core DR 115: In contexts where deduction is done and fails, or in
20254 contexts where deduction is not done, if a template argument list is
20255 specified and it, along with any default template arguments, identifies
20256 a single function template specialization, then the template-id is an
20257 lvalue for the function template specialization. */
20259 tree
20261 {
20274 {
20277 }
20279 {
20282 }
20284 {
20287 }
20290 {
20294 /* If we got some explicit template args, we need to plug them into
20295 the affected templates before we try to unify, in case the
20296 explicit args will completely resolve the templates in question. */
20304 {
20317 {
20320 {
20323 }
20325 {
20328 }
20329 }
20330 }
20332 {
20340 {
20341 tree base
20344 }
20348 }
20350 /* There were no good options and at least one bad one, so let the
20351 user know what the problem is. */
20353 }
20355 }
20357 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20358 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20359 different overloads deduce different arguments for a given parm.
20360 ADDR_P is true if the expression for which deduction is being
20361 performed was of the form "& fn" rather than simply "fn".
20363 Returns 1 on success. */
20365 static int
20367 tree orig_targs,
20368 tree targs,
20369 tree parm,
20370 tree arg,
20371 unification_kind_t strict,
20375 {
20377 tree tempargs;
20383 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20384 to function or pointer to member function argument if the set of
20385 overloaded functions does not contain function templates and at most
20386 one of a set of overloaded functions provides a unique match.
20388 So if this is a template, just return success. */
20400 /* We don't copy orig_targs for this because if we have already deduced
20401 some template args from previous args, unify would complain when we
20402 try to deduce a template parameter for the same argument, even though
20403 there isn't really a conflict. */
20410 /* First make sure we didn't deduce anything that conflicts with
20411 explicitly specified args. */
20413 {
20420 /* Since we're unifying against ourselves, we will fill in
20421 template args used in the function parm list with our own
20422 template parms. Discard them. */
20425 {
20426 /* Check that the argument at each index of the deduced argument pack
20427 is equivalent to the corresponding explicitly specified argument.
20428 We may have deduced more arguments than were explicitly specified,
20429 and that's OK. */
20431 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20432 that's wrong if we deduce the same argument pack from multiple
20433 function arguments: it's only incomplete the first time. */
20446 }
20449 }
20452 {
20457 }
20460 }
20462 /* PARM is a template class (perhaps with unbound template
20463 parameters). ARG is a fully instantiated type. If ARG can be
20464 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20465 TARGS are as for unify. */
20467 static tree
20470 {
20471 tree copy_of_targs;
20481 /* We need to make a new template argument vector for the call to
20482 unify. If we used TARGS, we'd clutter it up with the result of
20483 the attempted unification, even if this class didn't work out.
20484 We also don't want to commit ourselves to all the unifications
20485 we've already done, since unification is supposed to be done on
20486 an argument-by-argument basis. In other words, consider the
20487 following pathological case:
20489 template <int I, int J, int K>
20490 struct S {};
20492 template <int I, int J>
20493 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20495 template <int I, int J, int K>
20496 void f(S<I, J, K>, S<I, I, I>);
20498 void g() {
20499 S<0, 0, 0> s0;
20500 S<0, 1, 2> s2;
20502 f(s0, s2);
20503 }
20505 Now, by the time we consider the unification involving `s2', we
20506 already know that we must have `f<0, 0, 0>'. But, even though
20507 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20508 because there are two ways to unify base classes of S<0, 1, 2>
20509 with S<I, I, I>. If we kept the already deduced knowledge, we
20510 would reject the possibility I=1. */
20514 {
20518 }
20520 /* If unification failed, we're done. */
20526 }
20528 /* Given a template type PARM and a class type ARG, find the unique
20529 base type in ARG that is an instance of PARM. We do not examine
20530 ARG itself; only its base-classes. If there is not exactly one
20531 appropriate base class, return NULL_TREE. PARM may be the type of
20532 a partial specialization, as well as a plain template type. Used
20533 by unify. */
20535 static enum template_base_result
20538 {
20540 tree binfo;
20546 {
20547 /* The type could not be completed. */
20550 }
20552 /* Walk in inheritance graph order. The search order is not
20553 important, and this avoids multiple walks of virtual bases. */
20555 {
20560 {
20561 /* If there is more than one satisfactory baseclass, then:
20563 [temp.deduct.call]
20565 If they yield more than one possible deduced A, the type
20566 deduction fails.
20568 applies. */
20570 {
20573 }
20576 }
20577 }
20581 }
20583 /* Returns the level of DECL, which declares a template parameter. */
20585 static int
20587 {
20589 {
20599 }
20601 }
20603 /* Decide whether ARG can be unified with PARM, considering only the
20604 cv-qualifiers of each type, given STRICT as documented for unify.
20605 Returns nonzero iff the unification is OK on that basis. */
20607 static int
20609 {
20615 {
20616 /* Although a CVR qualifier is ignored when being applied to a
20617 substituted template parameter ([8.3.2]/1 for example), that
20618 does not allow us to unify "const T" with "int&" because both
20619 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20620 It is ok when we're allowing additional CV qualifiers
20621 at the outer level [14.8.2.1]/3,1st bullet. */
20631 }
20642 }
20644 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20645 void
20647 {
20651 {
20654 }
20655 else
20656 {
20659 }
20660 }
20662 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20663 do { \
20664 if (unify (TP, TA, P, A, S, EP)) \
20665 return 1; \
20666 } while (0)
20668 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20669 expansion at the end of PACKED_PARMS. Returns 0 if the type
20670 deduction succeeds, 1 otherwise. STRICT is the same as in
20671 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20672 function call argument list. We'll need to adjust the arguments to make them
20673 types. SUBR tells us if this is from a recursive call to
20674 type_unification_real, or for comparing two template argument
20675 lists. */
20677 static int
20681 {
20682 tree parm
20688 /* Add in any args remembered from an earlier partial instantiation. */
20696 /* Determine the parameter packs we will be deducing from the
20697 pattern, and record their current deductions. */
20700 {
20704 /* Only template parameter packs can be deduced, not e.g. function
20705 parameter packs or __bases or __integer_pack. */
20709 /* Determine the index and level of this parameter pack. */
20714 /* Keep track of the parameter packs and their corresponding
20715 argument packs. */
20718 }
20720 /* Loop through all of the arguments that have not yet been
20721 unified and unify each with the pattern. */
20723 {
20724 tree parm;
20728 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20729 or the element of its argument pack at the current index if
20730 this argument was explicitly specified. */
20732 {
20741 {
20744 }
20746 }
20748 /* If we had explicit template arguments, substitute them into the
20749 pattern before deduction. */
20751 {
20752 /* Some arguments might still be unspecified or dependent. */
20760 NULL_TREE);
20765 }
20766 else
20769 /* Unify the pattern with the current argument. */
20771 explain_p))
20774 /* For each parameter pack, collect the deduced value. */
20776 {
20782 }
20783 }
20785 /* Verify that the results of unification with the parameter packs
20786 produce results consistent with what we've seen before, and make
20787 the deduced argument packs available. */
20789 {
20796 /* By default keep the original deduced argument pack.
20797 If necessary, more specific code is going to update the
20798 resulting deduced argument later down in this function. */
20802 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20803 actually deduce anything. */
20811 {
20812 /* If we had fewer function args than explicit template args,
20813 just use the explicits. */
20818 }
20821 {
20822 tree result;
20823 /* Build the deduced *_ARGUMENT_PACK. */
20825 {
20828 }
20829 else
20834 /* Note the deduced argument packs for this parameter
20835 pack. */
20837 }
20841 {
20842 /* We only had the explicitly-provided arguments before, but
20843 now we have a complete set of arguments. */
20849 }
20850 else
20851 {
20857 /* Inconsistent unification of this parameter pack. */
20859 bad_old_arg,
20860 bad_new_arg);
20861 }
20862 }
20865 }
20867 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20868 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20869 parameters and return value are as for unify. */
20871 static int
20875 {
20876 tree parm_max;
20877 tree arg_max;
20881 /* Our representation of array types uses "N - 1" as the
20882 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20883 not an integer constant. We cannot unify arbitrarily
20884 complex expressions, so we eliminate the MINUS_EXPRs
20885 here. */
20889 {
20892 }
20896 {
20897 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20898 trying to unify the type of a variable with the type
20899 of a template parameter. For example:
20901 template <unsigned int N>
20902 void f (char (&) [N]);
20903 int g();
20904 void h(int i) {
20905 char a[g(i)];
20906 f(a);
20907 }
20909 Here, the type of the ARG will be "int [g(i)]", and
20910 may be a SAVE_EXPR, etc. */
20914 }
20916 /* If only one of the bounds used a MINUS_EXPR, compensate
20917 by adding one to the other bound. */
20920 integer_type_node,
20921 parm_max,
20922 integer_one_node);
20925 integer_type_node,
20926 arg_max,
20927 integer_one_node);
20931 }
20933 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20937 static pa_kind_t
20939 {
20948 else
20950 }
20952 /* Deduce the value of template parameters. TPARMS is the (innermost)
20953 set of template parameters to a template. TARGS is the bindings
20954 for those template parameters, as determined thus far; TARGS may
20955 include template arguments for outer levels of template parameters
20956 as well. PARM is a parameter to a template function, or a
20957 subcomponent of that parameter; ARG is the corresponding argument.
20958 This function attempts to match PARM with ARG in a manner
20959 consistent with the existing assignments in TARGS. If more values
20960 are deduced, then TARGS is updated.
20962 Returns 0 if the type deduction succeeds, 1 otherwise. The
20963 parameter STRICT is a bitwise or of the following flags:
20965 UNIFY_ALLOW_NONE:
20966 Require an exact match between PARM and ARG.
20967 UNIFY_ALLOW_MORE_CV_QUAL:
20968 Allow the deduced ARG to be more cv-qualified (by qualification
20969 conversion) than ARG.
20970 UNIFY_ALLOW_LESS_CV_QUAL:
20971 Allow the deduced ARG to be less cv-qualified than ARG.
20972 UNIFY_ALLOW_DERIVED:
20973 Allow the deduced ARG to be a template base class of ARG,
20974 or a pointer to a template base class of the type pointed to by
20975 ARG.
20976 UNIFY_ALLOW_INTEGER:
20977 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20978 case for more information.
20979 UNIFY_ALLOW_OUTER_LEVEL:
20980 This is the outermost level of a deduction. Used to determine validity
20981 of qualification conversions. A valid qualification conversion must
20982 have const qualified pointers leading up to the inner type which
20983 requires additional CV quals, except at the outer level, where const
20984 is not required [conv.qual]. It would be normal to set this flag in
20985 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20986 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20987 This is the outermost level of a deduction, and PARM can be more CV
20988 qualified at this point.
20989 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20990 This is the outermost level of a deduction, and PARM can be less CV
20991 qualified at this point. */
20993 static int
20996 {
20998 tree targ;
20999 tree tparm;
21001 tsubst_flags_t complain = (explain_p
21002 ? tf_warning_or_error
21005 /* I don't think this will do the right thing with respect to types.
21006 But the only case I've seen it in so far has been array bounds, where
21007 signedness is the only information lost, and I think that will be
21008 okay. */
21016 /* We can't deduce anything from this, but we might get all the
21017 template args from other function args. */
21023 /* If PARM uses template parameters, then we can't bail out here,
21024 even if ARG == PARM, since we won't record unifications for the
21025 template parameters. We might need them if we're trying to
21026 figure out which of two things is more specialized. */
21030 /* Handle init lists early, so the rest of the function can assume
21031 we're dealing with a type. */
21033 {
21038 /* Replace T with std::initializer_list<T> for deduction. */
21045 /* We can only deduce from an initializer list argument if the
21046 parameter is std::initializer_list or an array; otherwise this
21047 is a non-deduced context. */
21052 else
21053 {
21055 /* Deduction is defined in terms of a single type, so just punt
21056 on the (bizarre) std::initializer_list<T...>. */
21059 }
21062 {
21069 {
21073 /* It should only be possible to get here for a call. */
21075 elt_strict |= maybe_adjust_types_for_deduction
21078 }
21081 explain_p);
21082 }
21086 {
21087 /* Also deduce from the length of the initializer list. */
21094 }
21096 /* If the std::initializer_list<T> deduction worked, replace the
21097 deduced A with std::initializer_list<A>. */
21099 {
21104 }
21106 }
21108 /* If parm and arg aren't the same kind of thing (template, type, or
21109 expression), fail early. */
21113 /* Immediately reject some pairs that won't unify because of
21114 cv-qualification mismatches. */
21117 /* It is the elements of the array which hold the cv quals of an array
21118 type, and the elements might be template type parms. We'll check
21119 when we recurse. */
21121 /* We check the cv-qualifiers when unifying with template type
21122 parameters below. We want to allow ARG `const T' to unify with
21123 PARM `T' for example, when computing which of two templates
21124 is more specialized, for example. */
21138 {
21142 /* In a type which contains a nested-name-specifier, template
21143 argument values cannot be deduced for template parameters used
21144 within the nested-name-specifier. */
21156 /* The PARM is not one we're trying to unify. Just check
21157 to see if it matches ARG. */
21158 {
21163 else
21165 }
21172 /* Check for mixed types and values. */
21180 {
21183 {
21184 /* First try to match ARG directly. */
21186 explain_p);
21188 {
21189 /* Otherwise, look for a suitable base of ARG, as below. */
21196 }
21197 }
21198 /* ARG must be constructed from a template class or a template
21199 template parameter. */
21204 /* Deduce arguments T, i from TT<T> or TT<i>. */
21210 /* Fall through to deduce template name. */
21211 }
21215 {
21216 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21218 /* Simple cases: Value already set, does match or doesn't. */
21223 }
21224 else
21225 {
21226 /* If PARM is `const T' and ARG is only `int', we don't have
21227 a match unless we are allowing additional qualification.
21228 If ARG is `const int' and PARM is just `T' that's OK;
21229 that binds `const int' to `T'. */
21234 /* Consider the case where ARG is `const volatile int' and
21235 PARM is `const T'. Then, T should be `volatile int'. */
21236 arg = cp_build_qualified_type_real
21241 /* Simple cases: Value already set, does match or doesn't. */
21247 /* Make sure that ARG is not a variable-sized array. (Note
21248 that were talking about variable-sized arrays (like
21249 `int[n]'), rather than arrays of unknown size (like
21250 `int[]').) We'll get very confused by such a type since
21251 the bound of the array is not constant, and therefore
21252 not mangleable. Besides, such types are not allowed in
21253 ISO C++, so we can do as we please here. We do allow
21254 them for 'auto' deduction, since that isn't ABI-exposed. */
21258 /* Strip typedefs as in convert_template_argument. */
21260 }
21262 /* If ARG is a parameter pack or an expansion, we cannot unify
21263 against it unless PARM is also a parameter pack. */
21268 /* If the argument deduction results is a METHOD_TYPE,
21269 then there is a problem.
21270 METHOD_TYPE doesn't map to any real C++ type the result of
21271 the deduction can not be of that type. */
21285 {
21286 /* The PARM is not one we're trying to unify. Just check
21287 to see if it matches ARG. */
21293 }
21299 {
21303 /* We're deducing from an array bound, the type doesn't matter. */
21309 }
21311 /* [temp.deduct.type] If, in the declaration of a function template
21312 with a non-type template-parameter, the non-type
21313 template-parameter is used in an expression in the function
21314 parameter-list and, if the corresponding template-argument is
21315 deduced, the template-argument type shall match the type of the
21316 template-parameter exactly, except that a template-argument
21317 deduced from an array bound may be of any integral type.
21318 The non-type parameter might use already deduced type parameters. */
21321 /* We don't have enough levels of args to do any substitution. This
21323 else
21324 {
21330 {
21334 }
21335 }
21338 /* Template-parameter dependent expression. Just accept it for now.
21339 It will later be processed in convert_template_argument. */
21340 ;
21346 /* Convert the ARG to the type of PARM; the deduced non-type
21347 template argument must exactly match the types of the
21348 corresponding parameter. */
21351 {
21352 /* We haven't deduced the type of this parameter yet. */
21354 /* We deduce from array bounds in try_array_deduction. */
21356 {
21357 /* Deduce it from the non-type argument. */
21362 }
21363 else
21364 /* Try again later. */
21366 }
21367 else
21370 /* If ARG is a parameter pack or an expansion, we cannot unify
21371 against it unless PARM is also a parameter pack. */
21376 {
21379 }
21384 {
21385 /* A pointer-to-member constant can be unified only with
21386 another constant. */
21390 /* Just unify the class member. It would be useless (and possibly
21391 wrong, depending on the strict flags) to unify also
21392 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21393 arg refer to the same variable, even if through different
21394 classes. For instance:
21396 struct A { int x; };
21397 struct B : A { };
21399 Unification of &A::x and &B::x must succeed. */
21402 }
21405 {
21409 /* [temp.deduct.call]
21411 A can be another pointer or pointer to member type that can
21412 be converted to the deduced A via a qualification
21413 conversion (_conv.qual_).
21415 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21416 This will allow for additional cv-qualification of the
21417 pointed-to types if appropriate. */
21420 /* The derived-to-base conversion only persists through one
21421 level of pointers. */
21426 }
21458 /* We have already checked cv-qualification at the top of the
21459 function. */
21463 /* As far as unification is concerned, this wins. Later checks
21464 will invalidate it if necessary. */
21467 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21468 /* Type INTEGER_CST can come from ordinary constant template args. */
21480 {
21490 /* Check for pack expansions in the parameters. */
21492 {
21494 {
21496 /* We can unify against something with a trailing
21497 parameter pack. */
21499 else
21500 /* [temp.deduct.type]/9: If the template argument list of
21501 P contains a pack expansion that is not the last
21502 template argument, the entire template argument list
21503 is a non-deduced context. */
21505 }
21506 }
21508 /* If we don't have enough arguments to satisfy the parameters
21509 (not counting the pack expression at the end), or we have
21510 too many arguments for a parameter list that doesn't end in
21511 a pack expression, we can't unify. */
21517 /* Unify all of the parameters that precede the (optional)
21518 pack expression. */
21520 {
21525 }
21528 DEDUCE_EXACT,
21531 }
21539 {
21547 }
21552 {
21556 {
21557 /* First, we try to unify the PARM and ARG directly. */
21562 {
21563 /* Fallback to the special case allowed in
21564 [temp.deduct.call]:
21566 If P is a class, and P has the form
21567 template-id, then A can be a derived class of
21568 the deduced A. Likewise, if P is a pointer to
21569 a class of the form template-id, A can be a
21570 pointer to a derived class pointed to by the
21571 deduced A. */
21577 {
21578 /* Don't give the derived diagnostic if we're
21579 already dealing with the same template. */
21580 bool same_template
21586 }
21587 }
21588 }
21592 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21593 Then, we should unify `int' and `U'. */
21595 else
21596 /* There's no chance of unification succeeding. */
21601 }
21608 {
21611 tree a;
21617 /* CV qualifications for methods can never be deduced, they must
21618 match exactly. We need to check them explicitly here,
21619 because type_unification_real treats them as any other
21620 cv-qualified parameter. */
21622 && (!check_cv_quals_for_unify
21650 {
21662 }
21665 }
21668 /* Unify a pointer to member with a pointer to member function, which
21669 deduces the type of the member as a function type. */
21671 {
21672 /* Check top-level cv qualifiers */
21680 /* Determine the type of the function we are unifying against. */
21684 }
21703 /* Matched cases are handled by the ARG == PARM test above. */
21707 /* We might get a variable as a non-type template argument in parm if the
21708 corresponding parameter is type-dependent. Make any necessary
21709 adjustments based on whether arg is a reference. */
21713 {
21718 }
21719 /* Now use the normal expression code to check whether they match. */
21730 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21731 or UNDERLYING_TYPE nodes. */
21735 /* Unification fails if we hit an error node. */
21740 {
21750 }
21751 /* FALLTHRU */
21754 /* An unresolved overload is a nondeduced context. */
21758 expr:
21759 /* We must be looking at an expression. This can happen with
21760 something like:
21762 template <int I>
21763 void foo(S<I>, S<I + 2>);
21765 This is a "nondeduced context":
21767 [deduct.type]
21769 The nondeduced contexts are:
21771 --A type that is a template-id in which one or more of
21772 the template-arguments is an expression that references
21773 a template-parameter.
21775 In these cases, we assume deduction succeeded, but don't
21776 actually infer any unifications. */
21781 else
21783 }
21784 }
21785 #undef RECUR_AND_CHECK_FAILURE
21786 \f
21787 /* Note that DECL can be defined in this translation unit, if
21788 required. */
21790 static void
21792 {
21793 tree clone;
21797 }
21799 /* Called if RESULT is explicitly instantiated, or is a member of an
21800 explicitly instantiated class. */
21802 void
21804 {
21807 /* If this entity has already been written out, it's too late to
21808 make any modifications. */
21812 /* For anonymous namespace we don't need to do anything. */
21814 {
21817 }
21820 /* The TREE_PUBLIC flag for function declarations will have been
21821 set correctly by tsubst. */
21824 /* This might have been set by an earlier implicit instantiation. */
21829 else
21830 {
21833 /* Always make artificials weak. */
21836 /* For WIN32 we also want to put explicit instantiations in
21837 linkonce sections. */
21840 }
21842 /* If EXTERN_P, then this function will not be emitted -- unless
21843 followed by an explicit instantiation, at which point its linkage
21844 will be adjusted. If !EXTERN_P, then this function will be
21845 emitted here. In neither circumstance do we want
21846 import_export_decl to adjust the linkage. */
21848 }
21850 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21851 important template arguments. If any are missing, we check whether
21852 they're important by using error_mark_node for substituting into any
21853 args that were used for partial ordering (the ones between ARGS and END)
21854 and seeing if it bubbles up. */
21856 static bool
21858 {
21863 {
21866 }
21868 {
21872 }
21874 }
21876 /* Given two function templates PAT1 and PAT2, return:
21878 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21879 -1 if PAT2 is more specialized than PAT1.
21880 0 if neither is more specialized.
21882 LEN indicates the number of parameters we should consider
21883 (defaulted parameters should not be considered).
21885 The 1998 std underspecified function template partial ordering, and
21886 DR214 addresses the issue. We take pairs of arguments, one from
21887 each of the templates, and deduce them against each other. One of
21888 the templates will be more specialized if all the *other*
21889 template's arguments deduce against its arguments and at least one
21890 of its arguments *does* *not* deduce against the other template's
21891 corresponding argument. Deduction is done as for class templates.
21892 The arguments used in deduction have reference and top level cv
21893 qualifiers removed. Iff both arguments were originally reference
21894 types *and* deduction succeeds in both directions, an lvalue reference
21895 wins against an rvalue reference and otherwise the template
21896 with the more cv-qualified argument wins for that pairing (if
21897 neither is more cv-qualified, they both are equal). Unlike regular
21898 deduction, after all the arguments have been deduced in this way,
21899 we do *not* verify the deduced template argument values can be
21900 substituted into non-deduced contexts.
21902 The logic can be a bit confusing here, because we look at deduce1 and
21903 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21904 can find template arguments for pat1 to make arg1 look like arg2, that
21905 means that arg2 is at least as specialized as arg1. */
21907 int
21909 {
21922 /* Remove the this parameter from non-static member functions. If
21923 one is a non-static member function and the other is not a static
21924 member function, remove the first parameter from that function
21925 also. This situation occurs for operator functions where we
21926 locate both a member function (with this pointer) and non-member
21927 operator (with explicit first operand). */
21929 {
21934 }
21936 {
21939 {
21940 len--;
21942 }
21943 }
21945 /* If only one is a conversion operator, they are unordered. */
21949 /* Consider the return type for a conversion function */
21951 {
21954 len++;
21955 }
21957 processing_template_decl++;
21963 /* Stop when an ellipsis is seen. */
21965 {
21976 {
21977 /* When both arguments are pack expansions, we need only
21978 unify the patterns themselves. */
21982 /* This is the last comparison we need to do. */
21984 }
21986 /* DR 1847: If a particular P contains no template-parameters that
21987 participate in template argument deduction, that P is not used to
21988 determine the ordering. */
21994 {
21998 }
22001 {
22005 }
22011 {
22017 /* Setup the parameter vector, which contains only ARG1. */
22020 /* Setup the argument vector, which contains the remaining
22021 arguments. */
22030 /* We cannot deduce in the other direction, because ARG1 is
22031 a pack expansion but ARG2 is not. */
22033 }
22035 {
22041 /* Setup the parameter vector, which contains only ARG1. */
22044 /* Setup the argument vector, which contains the remaining
22045 arguments. */
22054 /* We cannot deduce in the other direction, because ARG2 is
22055 a pack expansion but ARG1 is not.*/
22057 }
22059 else
22060 {
22061 /* The normal case, where neither argument is a pack
22062 expansion. */
22069 }
22071 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22072 arg2, then arg2 is not as specialized as arg1. */
22078 /* "If, for a given type, deduction succeeds in both directions
22079 (i.e., the types are identical after the transformations above)
22080 and both P and A were reference types (before being replaced with
22081 the type referred to above):
22082 - if the type from the argument template was an lvalue reference and
22083 the type from the parameter template was not, the argument type is
22084 considered to be more specialized than the other; otherwise,
22085 - if the type from the argument template is more cv-qualified
22086 than the type from the parameter template (as described above),
22087 the argument type is considered to be more specialized than the other;
22088 otherwise,
22089 - neither type is more specialized than the other." */
22092 {
22094 {
22097 else
22099 }
22101 {
22106 }
22107 }
22110 /* We've failed to deduce something in either direction.
22111 These must be unordered. */
22114 next:
22118 /* We have already processed all of the arguments in our
22119 handing of the pack expansion type. */
22124 }
22126 /* "In most cases, all template parameters must have values in order for
22127 deduction to succeed, but for partial ordering purposes a template
22128 parameter may remain without a value provided it is not used in the
22129 types being used for partial ordering."
22131 Thus, if we are missing any of the targs1 we need to substitute into
22132 origs1, then pat2 is not as specialized as pat1. This can happen when
22133 there is a nondeduced context. */
22139 processing_template_decl--;
22141 /* If both deductions succeed, the partial ordering selects the more
22142 constrained template. */
22144 {
22149 }
22151 /* All things being equal, if the next argument is a pack expansion
22152 for one function but not for the other, prefer the
22153 non-variadic function. FIXME this is bogus; see c++/41958. */
22157 {
22160 }
22166 else
22168 }
22170 /* Determine which of two partial specializations of TMPL is more
22171 specialized.
22173 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22174 to the first partial specialization. The TREE_PURPOSE is the
22175 innermost set of template parameters for the partial
22176 specialization. PAT2 is similar, but for the second template.
22178 Return 1 if the first partial specialization is more specialized;
22179 -1 if the second is more specialized; 0 if neither is more
22180 specialized.
22182 See [temp.class.order] for information about determining which of
22183 two templates is more specialized. */
22185 static int
22187 {
22188 tree targs;
22197 /* Just like what happens for functions, if we are ordering between
22198 different template specializations, we may encounter dependent
22199 types in the arguments, and we need our dependency check functions
22200 to behave correctly. */
22204 {
22207 }
22211 {
22214 }
22217 /* If both deductions succeed, the partial ordering selects the more
22218 constrained template. */
22222 /* In the case of a tie where at least one of the templates
22223 has a parameter pack at the end, the template with the most
22224 non-packed parameters wins. */
22226 && any_deductions
22229 {
22235 /* We don't count the pack expansion at the end. */
22245 }
22248 }
22250 /* Return the template arguments that will produce the function signature
22251 DECL from the function template FN, with the explicit template
22252 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22253 also match. Return NULL_TREE if no satisfactory arguments could be
22254 found. */
22256 static tree
22258 {
22262 tree decl_arg_types;
22265 tree arg;
22269 /* Never do unification on the 'this' parameter. */
22290 }
22292 /* Return the innermost template arguments that, when applied to a partial
22293 specialization SPEC_TMPL of TMPL, yield the ARGS.
22295 For example, suppose we have:
22297 template <class T, class U> struct S {};
22298 template <class T> struct S<T*, int> {};
22300 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22301 partial specialization and the ARGS will be {double*, int}. The resulting
22302 vector will be {double}, indicating that `T' is bound to `double'. */
22304 static tree
22306 {
22308 tree spec_args
22311 tree deduced_args;
22312 tree innermost_deduced_args;
22316 {
22320 innermost_deduced_args);
22321 }
22322 else
22326 again:
22335 {
22337 {
22343 }
22345 }
22349 {
22352 }
22354 /* Verify that nondeduced template arguments agree with the type
22355 obtained from argument deduction.
22357 For example:
22359 struct A { typedef int X; };
22360 template <class T, class U> struct C {};
22361 template <class T> struct C<T, typename T::X> {};
22363 Then with the instantiation `C<A, int>', we can deduce that
22364 `T' is `A' but unify () does not check whether `typename T::X'
22365 is `int'. */
22376 /* We only need to check the innermost arguments; the other
22377 arguments will always agree. */
22382 /* Now that we have bindings for all of the template arguments,
22383 ensure that the arguments deduced for the template template
22384 parameters have compatible template parameter lists. See the use
22385 of template_template_parm_bindings_ok_p in fn_type_unification
22386 for more information. */
22391 }
22393 // Compare two function templates T1 and T2 by deducing bindings
22394 // from one against the other. If both deductions succeed, compare
22395 // constraints to see which is more constrained.
22396 static int
22398 {
22403 {
22406 }
22409 {
22412 }
22414 // If both deductions succeed, then one may be more constrained.
22419 }
22421 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22422 Return the TREE_LIST node with the most specialized template, if
22423 any. If there is no most specialized template, the error_mark_node
22424 is returned.
22426 Note that this function does not look at, or modify, the
22427 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22428 returned is one of the elements of INSTANTIATIONS, callers may
22429 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22430 and retrieve it from the value returned. */
22432 tree
22434 {
22441 {
22447 {
22448 /* Equally specialized, move to next function. If there
22449 is no next function, nothing's most specialized. */
22454 }
22455 }
22458 /* Now verify that champ is better than everything earlier in the
22459 instantiation list. */
22462 {
22465 }
22466 }
22468 processing_template_decl--;
22474 }
22476 /* If DECL is a specialization of some template, return the most
22477 general such template. Otherwise, returns NULL_TREE.
22479 For example, given:
22481 template <class T> struct S { template <class U> void f(U); };
22483 if TMPL is `template <class U> void S<int>::f(U)' this will return
22484 the full template. This function will not trace past partial
22485 specializations, however. For example, given in addition:
22487 template <class T> struct S<T*> { template <class U> void f(U); };
22489 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22490 `template <class T> template <class U> S<T*>::f(U)'. */
22492 tree
22494 {
22496 {
22499 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22500 template friend, or a FIELD_DECL for a capture pack. */
22503 }
22505 /* Look for more and more general templates. */
22507 {
22508 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22509 (See cp-tree.h for details.) */
22518 /* Stop if we run into an explicitly specialized class template. */
22525 }
22528 }
22530 /* Return the most specialized of the template partial specializations
22531 which can produce TARGET, a specialization of some class or variable
22532 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22533 a TEMPLATE_DECL node corresponding to the partial specialization, while
22534 the TREE_PURPOSE is the set of template arguments that must be
22535 substituted into the template pattern in order to generate TARGET.
22537 If the choice of partial specialization is ambiguous, a diagnostic
22538 is issued, and the error_mark_node is returned. If there are no
22539 partial specializations matching TARGET, then NULL_TREE is
22540 returned, indicating that the primary template should be used. */
22542 static tree
22544 {
22546 tree t;
22547 tree champ;
22554 {
22558 }
22560 {
22563 }
22565 {
22569 }
22570 else
22575 /* For determining which partial specialization to use, only the
22576 innermost args are interesting. */
22578 {
22581 }
22584 {
22585 tree spec_args;
22589 {
22590 /* Substitute in the template args from the enclosing class. */
22594 }
22601 {
22605 /* Keep the candidate only if the constraints are satisfied,
22606 or if we're not compiling with concepts. */
22609 {
22612 }
22613 }
22614 }
22624 {
22627 ;
22628 else
22629 {
22631 {
22634 {
22637 }
22638 }
22640 }
22641 }
22645 {
22648 {
22651 }
22652 }
22655 {
22662 else
22666 {
22671 }
22674 }
22677 }
22679 /* Explicitly instantiate DECL. */
22681 void
22683 {
22688 /* An error occurred, for which grokdeclarator has already issued
22689 an appropriate message. */
22692 {
22695 }
22701 {
22702 /* There is an asymmetry here in the way VAR_DECLs and
22703 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22704 the latter, the DECL we get back will be marked as a
22705 template instantiation, and the appropriate
22706 DECL_TEMPLATE_INFO will be set up. This does not happen for
22707 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22708 should handle VAR_DECLs as it currently handles
22709 FUNCTION_DECLs. */
22711 {
22714 }
22717 {
22720 }
22722 {
22727 }
22728 }
22730 {
22733 }
22734 else
22737 /* Check for various error cases. Note that if the explicit
22738 instantiation is valid the RESULT will currently be marked as an
22739 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22740 until we get here. */
22743 {
22744 /* DR 259 [temp.spec].
22746 Both an explicit instantiation and a declaration of an explicit
22747 specialization shall not appear in a program unless the explicit
22748 instantiation follows a declaration of the explicit specialization.
22750 For a given set of template parameters, if an explicit
22751 instantiation of a template appears after a declaration of an
22752 explicit specialization for that template, the explicit
22753 instantiation has no effect. */
22755 }
22757 {
22758 /* [temp.spec]
22760 No program shall explicitly instantiate any template more
22761 than once.
22763 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22764 the first instantiation was `extern' and the second is not,
22765 and EXTERN_P for the opposite case. */
22768 /* If an "extern" explicit instantiation follows an ordinary
22769 explicit instantiation, the template is instantiated. */
22772 }
22774 {
22777 }
22779 {
22782 }
22785 ;
22787 {
22790 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22793 }
22794 else
22802 }
22804 static void
22806 {
22812 {
22815 }
22816 }
22818 /* Called from do_type_instantiation through binding_table_foreach to
22819 do recursive instantiation for the type bound in ENTRY. */
22820 static void
22822 {
22828 }
22830 /* Perform an explicit instantiation of template class T. STORAGE, if
22831 non-null, is the RID for extern, inline or static. COMPLAIN is
22832 nonzero if this is called from the parser, zero if called recursively,
22833 since the standard is unclear (as detailed below). */
22835 void
22837 {
22847 {
22848 tree tmpl =
22852 else
22855 }
22860 {
22863 t);
22865 }
22868 {
22870 {
22872 {
22875 "ISO C++ 1998 forbids the use of %<extern%> on "
22877 }
22878 else
22880 "ISO C++ forbids the use of %qE"
22882 }
22890 else
22891 {
22893 storage);
22895 }
22896 }
22899 {
22900 /* DR 259 [temp.spec].
22902 Both an explicit instantiation and a declaration of an explicit
22903 specialization shall not appear in a program unless the explicit
22904 instantiation follows a declaration of the explicit specialization.
22906 For a given set of template parameters, if an explicit
22907 instantiation of a template appears after a declaration of an
22908 explicit specialization for that template, the explicit
22909 instantiation has no effect. */
22911 }
22913 {
22914 /* [temp.spec]
22916 No program shall explicitly instantiate any template more
22917 than once.
22919 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22920 instantiation was `extern'. If EXTERN_P then the second is.
22921 These cases are OK. */
22928 /* If we've already instantiated the template, just return now. */
22931 }
22939 /* In contrast to implicit instantiation, where only the
22940 declarations, and not the definitions, of members are
22941 instantiated, we have here:
22943 [temp.explicit]
22945 The explicit instantiation of a class template specialization
22946 implies the instantiation of all of its members not
22947 previously explicitly specialized in the translation unit
22948 containing the explicit instantiation.
22950 Of course, we can't instantiate member template classes, since we
22951 don't have any arguments for them. Note that the standard is
22952 unclear on whether the instantiation of the members are
22953 *explicit* instantiations or not. However, the most natural
22954 interpretation is that it should be an explicit
22955 instantiation. */
22959 && !static_p
22962 {
22967 }
22972 }
22974 /* Given a function DECL, which is a specialization of TMPL, modify
22975 DECL to be a re-instantiation of TMPL with the same template
22976 arguments. TMPL should be the template into which tsubst'ing
22977 should occur for DECL, not the most general template.
22979 One reason for doing this is a scenario like this:
22981 template <class T>
22982 void f(const T&, int i);
22984 void g() { f(3, 7); }
22986 template <class T>
22987 void f(const T& t, const int i) { }
22989 Note that when the template is first instantiated, with
22990 instantiate_template, the resulting DECL will have no name for the
22991 first parameter, and the wrong type for the second. So, when we go
22992 to instantiate the DECL, we regenerate it. */
22994 static void
22996 {
22997 /* The arguments used to instantiate DECL, from the most general
22998 template. */
22999 tree code_pattern;
23003 /* Make sure that we can see identifiers, and compute access
23004 correctly. */
23008 {
23009 tree decl_parm;
23010 tree pattern_parm;
23011 tree specs;
23025 specs);
23027 /* Merge parameter declarations. */
23030 pattern_parm
23034 {
23035 tree parm_type;
23036 tree attributes;
23041 NULL_TREE);
23047 {
23050 }
23053 }
23054 /* Merge any parameters that match with the function parameter
23055 pack. */
23057 {
23059 tree expanded_types;
23060 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23061 the parameters in this function parameter pack. */
23066 {
23067 tree parm_type;
23068 tree attributes;
23071 /* Rename the parameter to include the index. */
23080 {
23083 }
23085 }
23086 }
23087 /* Merge additional specifiers from the CODE_PATTERN. */
23091 }
23093 {
23103 }
23104 else
23108 }
23110 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23111 substituted to get DECL. */
23113 tree
23115 {
23118 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23119 for the instantiation. This is not always the most general
23120 template. Consider, for example:
23122 template <class T>
23123 struct S { template <class U> void f();
23124 template <> void f<int>(); };
23126 and an instantiation of S<double>::f<int>. We want TD to be the
23127 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23129 more general template. */
23131 /* We must also deal with friend templates. Given:
23133 template <class T> struct S {
23134 template <class U> friend void f() {};
23135 };
23137 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23138 so far as the language is concerned, but that's still
23139 where we get the pattern for the instantiation from. On
23140 other hand, if the definition comes outside the class, say:
23142 template <class T> struct S {
23143 template <class U> friend void f();
23144 };
23145 template <class U> friend void f() {}
23147 we don't need to look any further. That's what the check for
23148 DECL_INITIAL is for. */
23152 {
23153 /* The present template, TD, should not be a definition. If it
23154 were a definition, we should be using it! Note that we
23155 cannot restructure the loop to just keep going until we find
23156 a template with a definition, since that might go too far if
23157 a specialization was declared, but not defined. */
23159 /* Fetch the more general template. */
23161 }
23164 }
23166 /* Returns true if we need to instantiate this template instance even if we
23167 know we aren't going to emit it. */
23169 bool
23171 {
23172 /* We always instantiate inline functions so that we can inline them. An
23173 explicit instantiation declaration prohibits implicit instantiation of
23174 non-inline functions. With high levels of optimization, we would
23175 normally inline non-inline functions -- but we're not allowed to do
23176 that for "extern template" functions. Therefore, we check
23177 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23181 /* And we need to instantiate static data members so that
23182 their initializers are available in integral constant
23183 expressions. */
23186 }
23188 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23189 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23190 error, true otherwise. */
23192 bool
23194 {
23197 /* Don't instantiate a noexcept-specification from template context. */
23212 {
23218 {
23219 /* If hash_set::add returns true, the element was already there. */
23224 fn);
23226 }
23228 {
23243 }
23244 else
23254 }
23257 {
23260 else
23262 }
23265 }
23267 /* We're starting to process the function INST, an instantiation of PATTERN;
23268 add their parameters to local_specializations. */
23270 static void
23272 {
23276 {
23280 }
23282 {
23284 {
23287 }
23288 else
23289 {
23290 /* Register the (value) argument pack as a specialization of
23291 TMPL_PARM, then move on. */
23294 }
23295 }
23297 }
23299 /* Produce the definition of D, a _DECL generated from a template. If
23300 DEFER_OK is true, then we don't have to actually do the
23301 instantiation now; we just have to do it sometime. Normally it is
23302 an error if this is an explicit instantiation but D is undefined.
23303 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23304 instantiated class template. */
23306 tree
23308 {
23310 tree gen_args;
23311 tree args;
23312 tree td;
23313 tree code_pattern;
23314 tree spec;
23315 tree gen_tmpl;
23323 /* This function should only be used to instantiate templates for
23324 functions and static member variables. */
23327 /* A concept is never instantiated. */
23330 /* Variables are never deferred; if instantiation is required, they
23331 are instantiated right away. That allows for better code in the
23332 case that an expression refers to the value of the variable --
23333 if the variable has a constant value the referring expression can
23334 take advantage of that fact. */
23338 /* Don't instantiate cloned functions. Instead, instantiate the
23339 functions they cloned. */
23347 /* D has already been instantiated or explicitly specialized, so
23348 there's nothing for us to do here.
23350 It might seem reasonable to check whether or not D is an explicit
23351 instantiation, and, if so, stop here. But when an explicit
23352 instantiation is deferred until the end of the compilation,
23353 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23354 the instantiation. */
23357 /* Check to see whether we know that this template will be
23358 instantiated in some other file, as with "extern template"
23359 extension. */
23362 /* In general, we do not instantiate such templates. */
23370 /* We should already have the extra args. */
23373 /* And what's in the hash table should match D. */
23377 /* This needs to happen before any tsubsting. */
23383 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23384 for the instantiation. */
23389 {
23390 /* Look up an explicit specialization, if any. */
23394 {
23397 }
23398 }
23402 /* We should never be trying to instantiate a member of a class
23403 template or partial specialization. */
23408 /* In the case of a friend template whose definition is provided
23409 outside the class, we may have too many arguments. Drop the
23410 ones we don't need. The same is true for specializations. */
23411 args = get_innermost_template_args
23415 {
23421 }
23422 else
23423 {
23428 else
23430 }
23432 /* We may be in the middle of deferred access check. Disable it now. */
23435 /* Unless an explicit instantiation directive has already determined
23436 the linkage of D, remember that a definition is available for
23437 this entity. */
23447 /* If D is a member of an explicitly instantiated class template,
23448 and no definition is available, treat it like an implicit
23449 instantiation. */
23452 {
23453 /* Leave linkage flags alone on instantiations with anonymous
23454 visibility. */
23456 {
23459 }
23461 }
23463 /* Defer all other templates, unless we have been explicitly
23464 forbidden from doing so. */
23466 template. */
23467 ! pattern_defined
23468 /* If it's OK to postpone instantiation, do so. */
23469 || defer_ok
23470 /* If this is a static data member that will be defined
23471 elsewhere, we don't want to instantiate the entire data
23472 member, but we do want to instantiate the initializer so that
23473 we can substitute that elsewhere. */
23475 /* Handle here a deleted function too, avoid generating
23476 its body (c++/61080). */
23478 {
23479 /* The definition of the static data member is now required so
23480 we must substitute the initializer. */
23484 {
23485 tree ns;
23486 tree init;
23495 args,
23498 /* If instantiating the initializer involved instantiating this
23499 again, don't call cp_finish_decl twice. */
23501 {
23502 /* Make sure the initializer is still constant, in case of
23503 circular dependency (template/instantiate6.C). */
23504 const_init
23508 LOOKUP_ONLYCONVERTING);
23509 }
23513 }
23515 /* We restore the source position here because it's used by
23516 add_pending_template. */
23522 /* [temp.explicit]
23524 The definition of a non-exported function template, a
23525 non-exported member function template, or a non-exported
23526 member function or static data member of a class template
23527 shall be present in every translation unit in which it is
23528 explicitly instantiated. */
23532 /* If we're in unevaluated context, we just wanted to get the
23533 constant value; this isn't an odr use, so don't queue
23534 a full instantiation. */
23537 /* ??? Historically, we have instantiated inline functions, even
23538 when marked as "extern template". */
23542 }
23543 /* Tell the repository that D is available in this translation unit
23544 -- and see if it is supposed to be instantiated here. */
23546 {
23547 /* In a PCH file, despite the fact that the repository hasn't
23548 requested instantiation in the PCH it is still possible that
23549 an instantiation will be required in a file that includes the
23550 PCH. */
23553 /* Instantiate inline functions so that the inliner can do its
23554 job, even though we'll not be emitting a copy of this
23555 function. */
23558 }
23561 tree fn_context;
23564 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23575 else
23576 {
23580 }
23582 /* Mark D as instantiated so that recursive calls to
23583 instantiate_decl do not try to instantiate it again. */
23586 /* Regenerate the declaration in case the template has been modified
23587 by a subsequent redeclaration. */
23590 /* We already set the file and line above. Reset them now in case
23591 they changed as a result of calling regenerate_decl_from_template. */
23595 {
23596 tree init;
23599 /* Clear out DECL_RTL; whatever was there before may not be right
23600 since we've reset the type of the declaration. */
23604 /* The initializer is placed in DECL_INITIAL by
23605 regenerate_decl_from_template so we don't need to
23606 push/pop_access_scope again here. Pull it out so that
23607 cp_finish_decl can process it. */
23612 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23613 initializer. That function will defer actual emission until
23614 we have a chance to determine linkage. */
23617 /* Enter the scope of D so that access-checking works correctly. */
23630 }
23634 {
23635 /* Set up the list of local specializations. */
23639 /* Set up context. */
23643 else
23646 /* Some typedefs referenced from within the template code need to be
23647 access checked at template instantiation time, i.e now. These
23648 types were added to the template at parsing time. Let's get those
23649 and perform the access checks then. */
23651 args);
23653 /* Create substitution entries for the parameters. */
23656 /* Substitute into the body of the function. */
23660 else
23661 {
23666 /* Set the current input_location to the end of the function
23667 so that finish_function knows where we are. */
23668 input_location
23671 /* Remember if we saw an infinite loop in the template. */
23672 current_function_infinite_loop
23674 }
23676 /* Finish the function. */
23680 else
23681 {
23684 }
23688 }
23690 /* We're not deferring instantiation any more. */
23695 else
23701 out:
23710 }
23712 /* Run through the list of templates that we wish we could
23713 instantiate, and instantiate any we can. RETRIES is the
23714 number of times we retry pending template instantiation. */
23716 void
23718 {
23722 /* Instantiating templates may trigger vtable generation. This in turn
23723 may require further template instantiations. We place a limit here
23724 to avoid infinite loop. */
23726 {
23730 "template instantiation depth exceeds maximum of %d"
23731 " instantiating %q+D, possibly from virtual table generation"
23735 /* Pretend that we defined it. */
23738 }
23740 do
23741 {
23746 {
23751 {
23753 {
23768 }
23771 }
23772 else
23773 {
23776 {
23777 instantiation
23783 }
23787 }
23790 /* If INSTANTIATION has been instantiated, then we don't
23791 need to consider it again in the future. */
23793 else
23794 {
23797 }
23800 }
23802 }
23806 }
23808 /* Substitute ARGVEC into T, which is a list of initializers for
23809 either base class or a non-static data member. The TREE_PURPOSEs
23810 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23811 instantiate_decl. */
23813 static tree
23815 {
23820 {
23821 tree decl;
23822 tree init;
23828 {
23829 tree expr;
23830 tree arg;
23832 /* Expand the base class expansion type into separate base
23833 classes. */
23835 tf_warning_or_error,
23836 NULL_TREE);
23840 /* We'll be building separate TREE_LISTs of arguments for
23841 each base. */
23847 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23848 expand each argument in the TREE_VALUE of t. */
23855 /* VOID_TYPE_NODE is used to indicate
23856 value-initialization. */
23857 {
23860 }
23861 else
23862 {
23863 /* Substitute parameter packs into each argument in the
23864 TREE_LIST. */
23867 {
23868 tree expanded_exprs;
23870 /* Expand the argument. */
23872 expanded_exprs
23874 tf_warning_or_error,
23875 NULL_TREE);
23879 /* Prepend each of the expanded expressions to the
23880 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23882 {
23887 }
23888 }
23891 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23892 since we built them backwards. */
23894 {
23897 }
23898 }
23899 }
23902 {
23904 {
23908 }
23909 else
23910 {
23911 tree tmp;
23926 /* If we had an initializer but it instantiated to nothing,
23927 value-initialize the object. This will only occur when
23928 the initializer was a pack expansion where the parameter
23929 packs used in that expansion were of length zero. */
23932 }
23936 {
23938 decl);
23940 }
23941 /* Look for a target constructor. */
23945 {
23948 {
23952 }
23954 }
23957 {
23961 }
23962 }
23963 }
23965 }
23967 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23969 static void
23971 {
23976 else
23978 }
23980 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23981 is the instantiation (which should have been created with
23982 start_enum) and ARGS are the template arguments to use. */
23984 static void
23986 {
23987 tree e;
23993 {
23994 tree value;
23995 tree decl;
23998 /* Note that in a template enum, the TREE_VALUE is the
23999 CONST_DECL, not the corresponding INTEGER_CST. */
24004 /* Give this enumeration constant the correct access. */
24007 /* Actually build the enumerator itself. Here we're assuming that
24008 enumerators can't have dependent attributes. */
24011 }
24021 }
24023 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24024 its type -- but without substituting the innermost set of template
24025 arguments. So, innermost set of template parameters will appear in
24026 the type. */
24028 tree
24030 {
24031 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24033 }
24035 /* Return truthvalue if we're processing a template different from
24036 the last one involved in diagnostics. */
24037 bool
24039 {
24041 }
24043 /* Remember current template involved in diagnostics. */
24044 void
24046 {
24048 }
24052 {
24054 }
24056 /* Return TRUE if current_function_decl is being instantiated, false
24057 otherwise. */
24059 bool
24061 {
24064 }
24066 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24067 type. Return false for ok, true for disallowed. Issue error and
24068 inform messages under control of COMPLAIN. */
24070 static bool
24072 {
24090 /* A bound template template parm could later be instantiated to have a valid
24091 nontype parm type via an alias template. */
24097 {
24100 else
24102 type);
24103 }
24105 }
24107 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24108 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24110 static bool
24112 {
24113 tree scope;
24115 /* [temp.dep.type]
24117 A type is dependent if it is:
24119 -- a template parameter. Template template parameters are types
24120 for us (since TYPE_P holds true for them) so we handle
24121 them here. */
24125 /* -- a qualified-id with a nested-name-specifier which contains a
24126 class-name that names a dependent type or whose unqualified-id
24127 names a dependent type. */
24131 /* An alias template specialization can be dependent even if the
24132 resulting type is not. */
24136 /* -- a cv-qualified type where the cv-unqualified type is
24137 dependent.
24138 No code is necessary for this bullet; the code below handles
24139 cv-qualified types, and we don't want to strip aliases with
24140 TYPE_MAIN_VARIANT because of DR 1558. */
24141 /* -- a compound type constructed from any dependent type. */
24151 {
24152 tree arg_type;
24157 arg_type;
24162 /* A value-dependent noexcept-specifier makes the type dependent. */
24165 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24166 affect overload resolution and treating it as dependent breaks
24167 things. */
24172 }
24173 /* -- an array type constructed from any dependent type or whose
24174 size is specified by a constant expression that is
24175 value-dependent.
24177 We checked for type- and value-dependence of the bounds in
24178 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24180 {
24185 }
24187 /* -- a template-id in which either the template name is a template
24188 parameter ... */
24191 /* ... or any of the template arguments is a dependent type or
24192 an expression that is type-dependent or value-dependent. */
24194 && (any_dependent_template_arguments_p
24198 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24199 dependent; if the argument of the `typeof' expression is not
24200 type-dependent, then it should already been have resolved. */
24206 /* A template argument pack is dependent if any of its packed
24207 arguments are. */
24209 {
24215 }
24217 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24218 be template parameters. */
24225 /* The standard does not specifically mention types that are local
24226 to template functions or local classes, but they should be
24227 considered dependent too. For example:
24229 template <int I> void f() {
24230 enum E { a = I };
24231 S<sizeof (E)> s;
24232 }
24234 The size of `E' cannot be known until the value of `I' has been
24235 determined. Therefore, `E' must be considered dependent. */
24239 /* Don't use type_dependent_expression_p here, as it can lead
24240 to infinite recursion trying to determine whether a lambda
24241 nested in a lambda is dependent (c++/47687). */
24245 && (any_dependent_template_arguments_p
24249 /* Other types are non-dependent. */
24251 }
24253 /* Returns TRUE if TYPE is dependent, in the sense of
24254 [temp.dep.type]. Note that a NULL type is considered dependent. */
24256 bool
24258 {
24259 /* If there are no template parameters in scope, then there can't be
24260 any dependent types. */
24262 {
24263 /* If we are not processing a template, then nobody should be
24264 providing us with a dependent type. */
24268 }
24270 /* If the type is NULL, we have not computed a type for the entity
24271 in question; in that case, the type is dependent. */
24275 /* Erroneous types can be considered non-dependent. */
24279 /* Getting here with global_type_node means we improperly called this
24280 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24283 /* If we have not already computed the appropriate value for TYPE,
24284 do so now. */
24286 {
24289 }
24292 }
24294 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24295 lookup. In other words, a dependent type that is not the current
24296 instantiation. */
24298 bool
24300 {
24303 }
24305 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24306 an unknown base of 'this' (and is therefore instantiation-dependent). */
24308 static bool
24310 {
24327 }
24329 /* T is a SCOPE_REF; return whether we need to consider it
24330 instantiation-dependent so that we can check access at instantiation
24331 time even though we know which member it resolves to. */
24333 static bool
24335 {
24342 else
24344 }
24346 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24347 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24348 expression. */
24350 /* Note that this predicate is not appropriate for general expressions;
24351 only constant expressions (that satisfy potential_constant_expression)
24352 can be tested for value dependence. */
24354 bool
24356 {
24360 /* A type-dependent expression is also value-dependent. */
24365 {
24367 /* A dependent member function of the current instantiation. */
24371 /* A dependent member function of the current instantiation. */
24378 /* A name that has not been looked up -- must be dependent. */
24382 /* A non-type template parm. */
24386 /* A non-type template parm. */
24392 /* A constant with literal type and is initialized
24393 with an expression that is value-dependent. */
24395 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24399 {
24403 }
24412 /* These expressions are value-dependent if the type to which
24413 the cast occurs is dependent or the expression being casted
24414 is value-dependent. */
24415 {
24421 /* A functional cast has a list of operands. */
24424 {
24425 /* If there are no operands, it must be an expression such
24426 as "int()". This should not happen for aggregate types
24427 because it would form non-constant expressions. */
24432 }
24438 }
24443 /* FALLTHRU */
24446 /* A `sizeof' expression is value-dependent if the operand is
24447 type-dependent or is a pack expansion. */
24456 /* An 'encode' expression is value-dependent if the operand is
24457 type-dependent. */
24466 /* All instantiation-dependent expressions should also be considered
24467 value-dependent. */
24475 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24476 is value-dependent. */
24477 {
24486 }
24489 {
24506 }
24517 {
24521 }
24524 /* Treat all requires-expressions as value-dependent so
24525 we don't try to fold them. */
24532 {
24539 {
24541 /* In a call to a constexpr member function, look through the
24542 implicit ADDR_EXPR on the object argument so that it doesn't
24543 cause the call to be considered value-dependent. We also
24544 look through it in potential_constant_expression. */
24551 }
24553 }
24559 {
24561 tree val;
24568 }
24571 /* Treat a GNU statement expression as dependent to avoid crashing
24572 under instantiate_non_dependent_expr; it can't be constant. */
24576 /* A constant expression is value-dependent if any subexpression is
24577 value-dependent. */
24579 {
24586 {
24590 {
24593 /* In some cases, some of the operands may be missing.
24594 (For example, in the case of PREDECREMENT_EXPR, the
24595 amount to increment by may be missing.) That doesn't
24596 make the expression dependent. */
24599 }
24600 }
24604 }
24606 }
24608 /* The expression is not value-dependent. */
24610 }
24612 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24613 [temp.dep.expr]. Note that an expression with no type is
24614 considered dependent. Other parts of the compiler arrange for an
24615 expression with type-dependent subexpressions to have no type, so
24616 this function doesn't have to be fully recursive. */
24618 bool
24620 {
24629 /* An unresolved name is always dependent. */
24635 /* A fold expression is type-dependent. */
24642 /* Some expression forms are never type-dependent. */
24656 /* The types of these expressions depends only on the type to which
24657 the cast occurs. */
24666 /* The types of these expressions depends only on the type created
24667 by the expression. */
24670 {
24671 /* For NEW_EXPR tree nodes created inside a template, either
24672 the object type itself or a TREE_LIST may appear as the
24673 operand 1. */
24676 /* This is an array type. We need to check array dimensions
24677 as well. */
24679 || value_dependent_expression_p
24681 else
24683 }
24686 {
24690 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24691 contains an identifier associated by name lookup with one or more
24692 declarations declared with a dependent type, or...a
24693 nested-name-specifier or qualified-id that names a member of an
24694 unknown specialization. */
24697 }
24707 {
24708 tree elt;
24712 {
24715 }
24717 }
24719 /* A static data member of the current instantiation with incomplete
24720 array type is type-dependent, as the definition and specializations
24721 can have different bounds. */
24728 /* An array of unknown bound depending on a variadic parameter, eg:
24730 template<typename... Args>
24731 void foo (Args... args)
24732 {
24733 int arr[] = { args... };
24734 }
24736 template<int... vals>
24737 void bar ()
24738 {
24739 int arr[] = { vals... };
24740 }
24742 If the array has no length and has an initializer, it must be that
24743 we couldn't determine its length in cp_complete_array_type because
24744 it is dependent. */
24752 /* A function or variable template-id is type-dependent if it has any
24753 dependent template arguments. */
24757 {
24758 /* Consider the innermost template arguments, since those are the ones
24759 that come from the template-id; the template arguments for the
24760 enclosing class do not make it type-dependent unless they are used in
24761 the type of the decl. */
24763 && (any_dependent_template_arguments_p
24766 }
24768 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24769 type-dependent. Checking this is important for functions with auto return
24770 type, which looks like a dependent type. */
24779 {
24783 }
24785 /* Always dependent, on the number of arguments if nothing else. */
24790 {
24795 {
24801 }
24802 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24807 {
24812 }
24815 {
24822 }
24832 }
24836 /* Dependent type attributes might not have made it from the decl to
24837 the type yet. */
24843 }
24845 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24846 type-dependent if the expression refers to a member of the current
24847 instantiation and the type of the referenced member is dependent, or the
24848 class member access expression refers to a member of an unknown
24849 specialization.
24851 This function returns true if the OBJECT in such a class member access
24852 expression is of an unknown specialization. */
24854 bool
24856 {
24857 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24858 dependent. */
24863 }
24865 /* walk_tree callback function for instantiation_dependent_expression_p,
24866 below. Returns non-zero if a dependent subexpression is found. */
24868 static tree
24871 {
24873 {
24874 /* We don't have to worry about decltype currently because decltype
24875 of an instantiation-dependent expr is a dependent type. This
24876 might change depending on the resolution of DR 1172. */
24879 }
24882 {
24883 /* Don't treat an argument list as dependent just because it has no
24884 TREE_TYPE. */
24892 /* Handle expressions with type operands. */
24897 {
24902 {
24905 else
24906 {
24909 }
24910 }
24912 }
24916 /* In a template, finish_class_member_access_expr creates a
24917 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24918 type-dependent, so that we can check access control at
24919 instantiation time (PR 42277). See also Core issue 1273. */
24926 else
24929 /* Treat statement-expressions as dependent. */
24933 /* Treat requires-expressions as dependent. */
24938 /* Treat calls to function concepts as dependent. */
24944 /* And variable concepts. */
24951 }
24955 else
24957 }
24959 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24960 sense defined by the ABI:
24962 "An expression is instantiation-dependent if it is type-dependent
24963 or value-dependent, or it has a subexpression that is type-dependent
24964 or value-dependent."
24966 Except don't actually check value-dependence for unevaluated expressions,
24967 because in sizeof(i) we don't care about the value of i. Checking
24968 type-dependence will in turn check value-dependence of array bounds/template
24969 arguments as needed. */
24971 bool
24973 {
24974 tree result;
24985 }
24987 /* As above, but also check value-dependence of the expression as a whole. */
24989 bool
24991 {
24994 }
24996 /* Like type_dependent_expression_p, but it also works while not processing
24997 a template definition, i.e. during substitution or mangling. */
24999 bool
25001 {
25007 }
25009 /* Returns TRUE if ARGS contains a type-dependent expression. */
25011 bool
25013 {
25015 tree arg;
25018 {
25021 }
25023 }
25025 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25026 expressions) contains any type-dependent expressions. */
25028 bool
25030 {
25036 }
25038 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25039 expressions) contains any value-dependent expressions. */
25041 bool
25043 {
25049 }
25051 /* Returns TRUE if the ARG (a template argument) is dependent. */
25053 bool
25055 {
25059 /* Assume a template argument that was wrongly written by the user
25060 is dependent. This is consistent with what
25061 any_dependent_template_arguments_p [that calls this function]
25062 does. */
25072 {
25075 /* A member template of a dependent class is not necessarily
25076 type-dependent, but it is a dependent template argument because it
25077 will be a member of an unknown specialization to that template. */
25080 }
25082 {
25086 {
25089 }
25092 }
25095 else
25098 }
25100 /* Returns true if ARGS (a collection of template arguments) contains
25101 any types that require structural equality testing. */
25103 bool
25105 {
25115 {
25118 {
25124 {
25125 /* Look inside the argument pack. */
25128 }
25131 {
25144 }
25145 }
25146 }
25149 }
25151 /* Returns true if ARGS (a collection of template arguments) contains
25152 any dependent arguments. */
25154 bool
25156 {
25166 {
25171 }
25174 }
25176 /* Returns true if ARGS contains any errors. */
25178 bool
25180 {
25188 {
25191 else
25193 }
25199 {
25204 }
25207 }
25209 /* Returns TRUE if the template TMPL is type-dependent. */
25211 bool
25213 {
25215 {
25220 }
25222 /* Template template parameters are dependent. */
25226 /* So are names that have not been looked up. */
25230 }
25232 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25234 bool
25236 {
25239 }
25241 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25242 are dependent. */
25244 bool
25246 {
25253 {
25275 {
25279 }
25283 {
25287 {
25292 }
25293 }
25294 }
25297 }
25299 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25300 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25301 no such TYPE can be found. Note that this function peers inside
25302 uninstantiated templates and therefore should be used only in
25303 extremely limited situations. ONLY_CURRENT_P restricts this
25304 peering to the currently open classes hierarchy (which is required
25305 when comparing types). */
25307 tree
25309 {
25310 tree scope;
25311 tree name;
25312 tree decl;
25314 tree pushed_scope;
25315 tree result;
25320 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25323 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25324 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25325 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25326 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25327 identifier of the TYPENAME_TYPE anymore.
25328 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25329 TYPENAME_TYPE instead, we avoid messing up with a possible
25330 typedef variant case. */
25333 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25334 it first before we can figure out what NAME refers to. */
25336 {
25338 /* Given a class template A with a dependent base with nested type C,
25339 typedef typename A::C::C C will land us here, as trying to resolve
25340 the initial A::C leads to the local C typedef, which leads back to
25341 A::C::C. So we break the recursion now. */
25343 else
25345 }
25346 /* If we don't know what SCOPE refers to, then we cannot resolve the
25347 TYPENAME_TYPE. */
25350 /* If this is a typedef, we don't want to look inside (c++/11987). */
25353 /* If SCOPE isn't the template itself, it will not have a valid
25354 TYPE_FIELDS list. */
25356 /* scope is either the template itself or a compatible instantiation
25357 like X<T>, so look up the name in the original template. */
25359 /* If scope has no fields, it can't be a current instantiation. Check this
25360 before currently_open_class to avoid infinite recursion (71515). */
25363 /* If the SCOPE is not the current instantiation, there's no reason
25364 to look inside it. */
25367 /* Enter the SCOPE so that name lookup will be resolved as if we
25368 were in the class definition. In particular, SCOPE will no
25369 longer be considered a dependent type. */
25371 /* Look up the declaration. */
25373 tf_warning_or_error);
25377 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25378 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25384 {
25388 }
25391 {
25392 /* Obtain the template and the arguments. */
25395 {
25396 /* We get here with a plain identifier because a previous tentative
25397 parse of the nested-name-specifier as part of a ptr-operator saw
25398 ::template X<A>. The use of ::template is necessary in a
25399 ptr-operator, but wrong in a declarator-id.
25401 [temp.names]: In a qualified-id of a declarator-id, the keyword
25402 template shall not appear at the top level. */
25406 }
25408 /* Instantiate the template. */
25414 }
25416 /* Leave the SCOPE. */
25420 /* If we failed to resolve it, return the original typename. */
25424 /* If lookup found a typename type, resolve that too. */
25426 {
25427 /* Ill-formed programs can cause infinite recursion here, so we
25428 must catch that. */
25432 }
25434 /* Qualify the resulting type. */
25440 }
25442 /* EXPR is an expression which is not type-dependent. Return a proxy
25443 for EXPR that can be used to compute the types of larger
25444 expressions containing EXPR. */
25446 tree
25448 {
25450 tree inner_expr;
25452 /* When checking, try to get a constant value for all non-dependent
25453 expressions in order to expose bugs in *_dependent_expression_p
25454 and constexpr. This can affect code generation, see PR70704, so
25455 only do this for -fchecking=2. */
25458 /* Don't do this during nsdmi parsing as it can lead to
25459 unexpected recursive instantiations. */
25461 /* Don't do this during concept expansion either and for
25462 the same reason. */
25468 /* Preserve OVERLOADs; the functions must be available to resolve
25469 types. */
25480 /* There is no need to return a proxy for a variable. */
25483 /* Preserve string constants; conversions from string constants to
25484 "char *" are allowed, even though normally a "const char *"
25485 cannot be used to initialize a "char *". */
25488 /* Preserve void and arithmetic constants, as an optimization -- there is no
25489 reason to create a new node. */
25494 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25495 There is at least one place where we want to know that a
25496 particular expression is a throw-expression: when checking a ?:
25497 expression, there are special rules if the second or third
25498 argument is a throw-expression. */
25502 /* Don't wrap an initializer list, we need to be able to look inside. */
25506 /* Don't wrap a dummy object, we need to be able to test for it. */
25525 /* If the type is unknown, it can't really be non-dependent */
25528 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25531 }
25533 /* ARGS is a vector of expressions as arguments to a function call.
25534 Replace the arguments with equivalent non-dependent expressions.
25535 This modifies ARGS in place. */
25537 void
25539 {
25541 tree arg;
25544 {
25548 }
25549 }
25551 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25552 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25553 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25555 static tree
25557 {
25571 }
25573 tree
25575 {
25577 }
25579 tree
25581 {
25583 }
25585 /* Return a C++17 deduction placeholder for class template TMPL. */
25587 tree
25589 {
25593 }
25595 /* True iff T is a C++17 class template deduction placeholder. */
25597 bool
25599 {
25601 }
25603 /* Make a "constrained auto" type-specifier. This is an
25604 auto type with constraints that must be associated after
25605 deduction. The constraint is formed from the given
25606 CONC and its optional sequence of arguments, which are
25607 non-null if written as partial-concept-id. */
25609 tree
25611 {
25614 /* Build the constraint. */
25622 /* Our canonical type depends on the constraint. */
25625 /* Attach the constraint to the type declaration. */
25628 }
25630 /* Given type ARG, return std::initializer_list<ARG>. */
25632 static tree
25634 {
25638 {
25642 "deducing from brace-enclosed initializer list"
25646 }
25652 }
25654 /* Replace auto in TYPE with std::initializer_list<auto>. */
25656 static tree
25658 {
25665 }
25667 /* Hash traits for hashing possibly constrained 'auto'
25668 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25671 {
25674 };
25676 /* Hash the 'auto' T. */
25678 inline hashval_t
25680 {
25682 /* Matching constrained-type-specifiers denote the same template
25683 parameter, so hash the constraint. */
25685 else
25686 /* But unconstrained autos are all separate, so just hash the pointer. */
25688 }
25690 /* Compare two 'auto's. */
25694 {
25701 /* Two unconstrained autos are distinct. */
25706 }
25708 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25709 constrained) auto, add it to the vector. */
25711 static int
25713 {
25716 {
25717 /* All the autos were built with index 0; fix that up now. */
25721 /* If this is a repeated constrained-type-specifier, use the index we
25722 chose before. */
25724 else
25725 {
25726 /* Otherwise this is new, so use the current count. */
25729 }
25731 }
25733 /* Always keep walking. */
25735 }
25737 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25738 says they can appear anywhere in the type. */
25740 static tree
25742 {
25751 {
25756 }
25759 }
25761 /* The stem for deduction guide names. */
25764 /* Return the name for a deduction guide for class template TMPL. */
25766 tree
25768 {
25779 }
25781 /* True if NAME is the name of a deduction guide. */
25783 bool
25785 {
25790 }
25792 /* True if FN is a deduction guide. */
25794 bool
25796 {
25801 }
25803 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25805 bool
25807 {
25814 }
25816 /* True if FN is a guide generated from a constructor template. */
25818 bool
25820 {
25828 }
25830 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25831 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25832 template parameter types. Note that the handling of template template
25833 parameters relies on current_template_parms being set appropriately for the
25834 new template. */
25836 static tree
25839 {
25845 tree newtype;
25848 {
25855 }
25856 else
25857 {
25860 {
25861 // Substitute once to fix references to other template parameters.
25864 // Now substitute again to reduce the level of the auto.
25867 }
25868 else
25871 }
25873 tree newdecl
25878 tree newidx;
25881 {
25891 {
25896 // First create a copy (ttargs) of tsubst_args with an
25897 // additional level for the template template parameter's own
25898 // template parameters (ttparms).
25899 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25907 // Substitute ttargs into ttparms to fix references to
25908 // other template parameters.
25911 // Now substitute again with args based on tparms, to reduce
25912 // the level of the ttparms.
25915 complain);
25916 // Finally, tack the adjusted parms onto tparms.
25918 current_template_parms);
25920 }
25921 }
25922 else
25923 {
25925 tree newconst
25937 }
25940 }
25942 /* Returns a C++17 class deduction guide template based on the constructor
25943 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25944 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25946 static tree
25948 {
25952 location_t loc;
25956 {
25960 {
25963 }
25964 else
25974 }
25975 else
25976 {
25980 fn_tmpl
25990 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25991 fully specialized args for the enclosing class. Strip those off, as
25992 the deduction guide won't have those template parameters. */
25995 /* Discard the 'this' parameter. */
26003 {
26006 /* For a member template constructor, we need to flatten the two
26007 template parameter lists into one, and then adjust the function
26008 signature accordingly. This gets...complicated. */
26011 /* For a member template we should have two levels of parms/args, one
26012 for the class and one for the constructor. We stripped
26013 specialized args for further enclosing classes above. */
26017 /* Template args for translating references to the two-level template
26018 parameters into references to the one-level template parameters we
26019 are creating. */
26024 /* Template parms for the constructor template. */
26027 /* Template parms for the class template. */
26031 /* Template parms for the deduction guide start as a copy of the
26032 template parms for the class. We set current_template_parms for
26033 lookup_template_class_1. */
26039 /* Now we need to rewrite the constructor parms to append them to the
26040 class parms. */
26042 {
26059 }
26061 /* Now we have a final set of template parms to substitute into the
26062 function signature. */
26071 }
26076 }
26079 {
26080 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26084 }
26088 FUNCTION_DECL,
26105 }
26107 /* Deduce template arguments for the class template placeholder PTYPE for
26108 template TMPL based on the initializer INIT, and return the resulting
26109 type. */
26111 static tree
26113 tsubst_flags_t complain)
26114 {
26116 {
26117 /* We should have handled this in the caller. */
26123 }
26134 {
26137 {
26138 /* As an exception, the first phase in 16.3.1.7 (considering the
26139 initializer list as a single argument) is omitted if the
26140 initializer list consists of a single expression of type cv U,
26141 where U is a specialization of C or a class derived from a
26142 specialization of C. */
26153 }
26156 else
26158 }
26159 else
26170 /* Prune explicit deduction guides in copy-initialization context. */
26172 {
26178 {
26179 /* Found a nonconverting guide, prune the candidates. */
26186 }
26187 }
26192 {
26195 }
26198 // FIXME cache artificial deduction guides
26200 {
26207 else
26211 }
26215 /* If this is list-initialization and the class has a list constructor, first
26216 try deducing from the list as a single argument, as [over.match.list]. */
26220 {
26224 }
26226 {
26232 {
26233 /* That didn't work, now try treating the list as a sequence of
26234 arguments. */
26237 }
26238 }
26240 /* Maybe generate an implicit deduction guide. */
26242 {
26246 /* Generate a copy guide. */
26249 /* Generate a default guide. */
26253 {
26258 }
26259 }
26262 {
26264 " of %qT, as it has no non-explicit deduction guides or "
26267 }
26269 {
26273 }
26276 {
26280 }
26283 {
26293 }
26298 }
26300 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26301 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26302 The CONTEXT determines the context in which auto deduction is performed
26303 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26304 OUTER_TARGS are used during template argument deduction
26305 (context == adc_unify) to properly substitute the result, and is ignored
26306 in other contexts.
26308 For partial-concept-ids, extra args may be appended to the list of deduced
26309 template arguments prior to determining constraint satisfaction. */
26311 tree
26315 {
26316 tree targs;
26323 /* Defining a subset of type-dependent expressions that we can deduce
26324 from ahead of time isn't worth the trouble. */
26327 /* Similarly, we can't deduce from another undeduced decl. */
26332 /* C++17 class template argument deduction. */
26336 /* Nothing we can do with this, even in deduction context. */
26339 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26340 with either a new invented type template parameter U or, if the
26341 initializer is a braced-init-list (8.5.4), with
26342 std::initializer_list<U>. */
26344 {
26349 else
26350 {
26352 {
26356 "for deduction to %<std::initializer_list%>, use copy-"
26358 }
26360 }
26361 }
26372 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26373 and initializer has array type, deduce cv-qualified array type. */
26375 complain);
26377 {
26386 {
26390 }
26391 }
26392 else
26393 {
26395 tree tparms;
26399 else
26400 {
26404 }
26411 {
26413 /* Try again at instantiation time. */
26417 /* If type is error_mark_node a diagnostic must have been
26418 emitted by now. Also, having a mention to '<type error>'
26419 in the diagnostic is not really useful to the user. */
26420 {
26424 else
26429 }
26431 }
26432 }
26434 /* Check any placeholder constraints against the deduced type. */
26437 {
26438 /* Use the deduced type to check the associated constraints. If we
26439 have a partial-concept-id, rebuild the argument list so that
26440 we check using the extra arguments. */
26444 {
26447 }
26448 else
26451 {
26453 {
26455 {
26473 }
26475 }
26477 }
26478 }
26484 }
26486 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26487 result. */
26489 tree
26491 {
26493 {
26499 /* In an abbreviated function template we didn't know we were dealing
26500 with a function template when we saw the auto return type, so update
26501 it to have the correct level. */
26503 }
26505 }
26507 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26508 'decltype(auto)' or a deduced class template. */
26510 bool
26512 {
26518 else
26520 }
26522 /* for_each_template_parm callback for type_uses_auto. */
26524 int
26526 {
26528 }
26530 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26531 a use of `auto'. Returns NULL_TREE otherwise. */
26533 tree
26535 {
26539 {
26540 /* The Concepts TS allows multiple autos in one type-specifier; just
26541 return the first one we find, do_auto_deduction will collect all of
26542 them. */
26546 else
26548 }
26549 else
26551 }
26553 /* For a given template T, return the vector of typedefs referenced
26554 in T for which access check is needed at T instantiation time.
26555 T is either a FUNCTION_DECL or a RECORD_TYPE.
26556 Those typedefs were added to T by the function
26557 append_type_to_template_for_access_check. */
26561 {
26562 tree ti;
26573 {
26578 }
26581 }
26583 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26584 tied to T. That list of typedefs will be access checked at
26585 T instantiation time.
26586 T is either a FUNCTION_DECL or a RECORD_TYPE.
26587 TYPE_DECL is a TYPE_DECL node representing a typedef.
26588 SCOPE is the scope through which TYPE_DECL is accessed.
26589 LOCATION is the location of the usage point of TYPE_DECL.
26591 This function is a subroutine of
26592 append_type_to_template_for_access_check. */
26594 static void
26596 tree type_decl,
26597 tree scope,
26598 location_t location)
26599 {
26600 qualified_typedef_usage_t typedef_usage;
26601 tree ti;
26608 && type_decl
26622 }
26624 /* Append TYPE_DECL to the template TEMPL.
26625 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26626 At TEMPL instanciation time, TYPE_DECL will be checked to see
26627 if it can be accessed through SCOPE.
26628 LOCATION is the location of the usage point of TYPE_DECL.
26630 e.g. consider the following code snippet:
26632 class C
26633 {
26634 typedef int myint;
26635 };
26637 template<class U> struct S
26638 {
26639 C::myint mi; // <-- usage point of the typedef C::myint
26640 };
26642 S<char> s;
26644 At S<char> instantiation time, we need to check the access of C::myint
26645 In other words, we need to check the access of the myint typedef through
26646 the C scope. For that purpose, this function will add the myint typedef
26647 and the scope C through which its being accessed to a list of typedefs
26648 tied to the template S. That list will be walked at template instantiation
26649 time and access check performed on each typedefs it contains.
26650 Note that this particular code snippet should yield an error because
26651 myint is private to C. */
26653 void
26655 tree type_decl,
26656 tree scope,
26657 location_t location)
26658 {
26664 /* Make sure we don't append the type to the template twice. */
26671 }
26673 /* Convert the generic type parameters in PARM that match the types given in the
26674 range [START_IDX, END_IDX) from the current_template_parms into generic type
26675 packs. */
26677 tree
26679 {
26690 {
26691 /* Create a distinct parameter pack type from the current parm and add it
26692 to the replacement args to tsubst below into the generic function
26693 parameter. */
26708 }
26714 /* If there are more levels then build up the replacement with the outer
26715 template parms. */
26719 replacement);
26722 }
26724 /* Entries in the decl_constraint hash table. */
26726 {
26727 tree decl;
26728 tree ci;
26729 };
26731 /* Hashing function and equality for constraint entries. */
26733 {
26735 {
26737 }
26740 {
26742 }
26743 };
26745 /* A mapping from declarations to constraint information. Note that
26746 both templates and their underlying declarations are mapped to the
26747 same constraint information.
26749 FIXME: This is defined in pt.c because garbage collection
26750 code is not being generated for constraint.cc. */
26754 /* Returns the template constraints of declaration T. If T is not
26755 constrained, return NULL_TREE. Note that T must be non-null. */
26757 tree
26759 {
26770 else
26772 }
26774 /* Associate the given constraint information CI with the declaration
26775 T. If T is a template, then the constraints are associated with
26776 its underlying declaration. Don't build associations if CI is
26777 NULL_TREE. */
26779 void
26781 {
26793 }
26795 /* Remove the associated constraints of the declaration T. */
26797 void
26799 {
26808 }
26810 /* Memoized satisfaction results for declarations. This
26811 maps the pair (constraint_info, arguments) to the result computed
26812 by constraints_satisfied_p. */
26815 {
26816 tree ci;
26817 tree args;
26818 tree result;
26819 };
26821 /* Hashing function and equality for constraint entries. */
26824 {
26826 {
26829 }
26832 {
26834 }
26835 };
26837 /* Memoized satisfaction results for concept checks. */
26840 {
26841 tree tmpl;
26842 tree args;
26843 tree result;
26844 };
26846 /* Hashing function and equality for constraint entries. */
26849 {
26851 {
26853 }
26856 {
26861 }
26862 };
26867 /* Search for a memoized satisfaction result. Returns one of the
26868 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26870 tree
26872 {
26877 else
26879 }
26881 /* Memoize the result of a satisfication test. Returns the saved result. */
26883 tree
26885 {
26892 }
26894 /* Search for a memoized satisfaction result for a concept. */
26896 tree
26898 {
26903 else
26905 }
26907 /* Memoize the result of a concept check. Returns the saved result. */
26909 tree
26911 {
26918 }
26922 /* Returns a prior concept specialization. This returns the substituted
26923 and normalized constraints defined by the concept. */
26925 tree
26927 {
26932 else
26934 }
26936 /* Save a concept expansion for later. */
26938 tree
26940 {
26947 }
26949 static hashval_t
26951 {
26960 }
26962 /* Compare the constraints of two subsumption entries. The LEFT1 and
26963 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26964 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26966 static bool
26968 {
26976 }
26978 /* Key/value pair for learning and memoizing subsumption results. This
26979 associates a pair of check constraints (including arguments) with
26980 a boolean value indicating the result. */
26983 {
26984 tree t1;
26985 tree t2;
26987 };
26989 /* Hashing function and equality for constraint entries. */
26992 {
26994 {
26996 }
26999 {
27004 }
27005 };
27009 /* Search for a previously cached subsumption result. */
27013 {
27018 else
27020 }
27022 /* Save a subsumption result. */
27024 bool
27026 {
27033 }
27035 /* Set up the hash table for constraint association. */
27037 void
27039 {
27048 }
27050 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27051 0..N-1. */
27053 void
27055 {
27058 integer_type_node,
27059 NULL_TREE),
27063 }
27065 /* Set up the hash tables for template instantiations. */
27067 void
27069 {
27075 }
27077 /* Print stats about the template hash tables for -fstats. */
27079 void
27081 {
27090 }
27092 #if CHECKING_P
27096 /* Verify that build_non_dependent_expr () works, for various expressions,
27097 and that location wrappers don't affect the results. */
27099 static void
27101 {
27104 /* Verify constants, without and with location wrappers. */
27121 }
27123 /* Verify that type_dependent_expression_p () works correctly, even
27124 in the presence of location wrapper nodes. */
27126 static void
27128 {
27133 /* If no templates are involved, nothing is type-dependent. */
27139 /* Within a template, an unresolved name is always type-dependent. */
27142 /* Ensure it copes with NULL_TREE and errors. */
27146 /* A USING_DECL in a template should be type-dependent, even if wrapped
27147 with a location wrapper (PR c++/83799). */
27156 }
27158 /* Run all of the selftests within this file. */
27160 void
27162 {
27165 }