| blob | c81bd5094d95dd693a74bb8ddacb8bec8b2df6f6 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 alias template (needed by instantiate_decl). */
232 static void
234 {
242 else
246 {
247 saved_access_scope = tree_cons
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 static void
258 {
260 {
263 }
267 else
269 }
271 /* Do any processing required when DECL (a member template
272 declaration) is finished. Returns the TEMPLATE_DECL corresponding
273 to DECL, unless it is a specialization, in which case the DECL
274 itself is returned. */
276 tree
278 {
285 {
286 tree type;
294 {
298 }
300 }
304 {
306 {
309 }
310 else
312 }
313 else
317 }
319 /* Create a template info node. */
321 tree
323 {
328 }
330 /* Return the template info node corresponding to T, whatever T is. */
332 tree
334 {
356 }
358 /* Returns the template nesting level of the indicated class TYPE.
360 For example, in:
361 template <class T>
362 struct A
363 {
364 template <class U>
365 struct B {};
366 };
368 A<T>::B<U> has depth two, while A<T> has depth one.
369 Both A<T>::B<int> and A<int>::B<U> have depth one, if
370 they are instantiations, not specializations.
372 This function is guaranteed to return 0 if passed NULL_TREE so
373 that, for example, `template_class_depth (current_class_type)' is
374 always safe. */
376 int
378 {
382 {
393 else
395 }
398 }
400 /* Subroutine of maybe_begin_member_template_processing.
401 Returns true if processing DECL needs us to push template parms. */
403 static bool
405 {
411 }
413 /* Subroutine of maybe_begin_member_template_processing.
414 Push the template parms in PARMS, starting from LEVELS steps into the
415 chain, and ending at the beginning, since template parms are listed
416 innermost first. */
418 static void
420 {
428 current_template_parms
434 NULL);
436 {
445 {
452 /* Push the CONST_DECL. */
458 }
459 }
460 }
462 /* Restore the template parameter context for a member template, a
463 friend template defined in a class definition, or a non-template
464 member of template class. */
466 void
468 {
469 tree parms;
474 {
477 /* Disregard full specializations (c++/60999). */
480 }
483 {
488 {
491 }
494 }
496 /* Remember how many levels of template parameters we pushed so that
497 we can pop them later. */
499 }
501 /* Undo the effects of maybe_begin_member_template_processing. */
503 void
505 {
514 {
518 }
519 }
521 /* Return a new template argument vector which contains all of ARGS,
522 but has as its innermost set of arguments the EXTRA_ARGS. */
524 static tree
526 {
527 tree new_args;
545 }
547 /* Like add_to_template_args, but only the outermost ARGS are added to
548 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
549 (EXTRA_ARGS) levels are added. This function is used to combine
550 the template arguments from a partial instantiation with the
551 template arguments used to attain the full instantiation from the
552 partial instantiation. */
554 static tree
556 {
557 tree new_args;
559 /* If there are more levels of EXTRA_ARGS than there are ARGS,
560 something very fishy is going on. */
563 /* If *all* the new arguments will be the EXTRA_ARGS, just return
564 them. */
568 /* For the moment, we make ARGS look like it contains fewer levels. */
573 /* Now, we restore ARGS to its full dimensions. */
577 }
579 /* Return the N levels of innermost template arguments from the ARGS. */
581 tree
583 {
584 tree new_args;
590 /* If N is 1, just return the innermost set of template arguments. */
594 /* If we're not removing anything, just return the arguments we were
595 given. */
601 /* Make a new set of arguments, not containing the outer arguments. */
608 }
610 /* The inverse of get_innermost_template_args: Return all but the innermost
611 EXTRA_LEVELS levels of template arguments from the ARGS. */
613 static tree
615 {
616 tree new_args;
622 /* If N is 1, just return the outermost set of template arguments. */
626 /* If we're not removing anything, just return the arguments we were
627 given. */
632 /* Make a new set of arguments, not containing the inner arguments. */
639 }
641 /* We've got a template header coming up; push to a new level for storing
642 the parms. */
644 void
646 {
647 /* We use a non-tag-transparent scope here, which causes pushtag to
648 put tags in this scope, rather than in the enclosing class or
649 namespace scope. This is the right thing, since we want
650 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
651 global template class, push_template_decl handles putting the
652 TEMPLATE_DECL into top-level scope. For a nested template class,
653 e.g.:
655 template <class T> struct S1 {
656 template <class T> struct S2 {};
657 };
659 pushtag contains special code to insert the TEMPLATE_DECL for S2
660 at the right scope. */
666 /* Add a dummy parameter level while we process the parameter list. */
667 current_template_parms
670 current_template_parms);
671 }
673 /* This routine is called when a specialization is declared. If it is
674 invalid to declare a specialization here, an error is reported and
675 false is returned, otherwise this routine will return true. */
677 static bool
679 {
682 /* [temp.expl.spec]
684 An explicit specialization shall be declared in the namespace of
685 which the template is a member, or, for member templates, in the
686 namespace of which the enclosing class or enclosing class
687 template is a member. An explicit specialization of a member
688 function, member class or static data member of a class template
689 shall be declared in the namespace of which the class template
690 is a member. */
692 {
695 }
697 /* [temp.expl.spec]
699 In an explicit specialization declaration for a member of a class
700 template or a member template that appears in namespace scope,
701 the member template and some of its enclosing class templates may
702 remain unspecialized, except that the declaration shall not
703 explicitly specialize a class member template if its enclosing
704 class templates are not explicitly specialized as well. */
706 {
709 }
712 }
714 /* We've just seen template <>. */
716 bool
718 {
722 }
724 /* Called at then end of processing a declaration preceded by
725 template<>. */
727 void
729 {
732 }
734 /* Any template <>'s that we have seen thus far are not referring to a
735 function specialization. */
737 void
739 {
742 }
744 /* We've just seen a template header. If SPECIALIZATION is nonzero,
745 it was of the form template <>. */
747 static void
749 {
751 template_header_count++;
752 }
754 /* We're beginning an explicit instantiation. */
756 void
758 {
761 }
764 void
766 {
769 }
771 /* An explicit specialization or partial specialization of TMPL is being
772 declared. Check that the namespace in which the specialization is
773 occurring is permissible. Returns false iff it is invalid to
774 specialize TMPL in the current namespace. */
776 static bool
778 {
781 /* [tmpl.expl.spec]
783 An explicit specialization shall be declared in a namespace enclosing the
784 specialized template. An explicit specialization whose declarator-id is
785 not qualified shall be declared in the nearest enclosing namespace of the
786 template, or, if the namespace is inline (7.3.1), any namespace from its
787 enclosing namespace set. */
790 {
793 }
796 /* Same or enclosing namespace. */
798 else
799 {
805 }
806 }
808 /* SPEC is an explicit instantiation. Check that it is valid to
809 perform this explicit instantiation in the current namespace. */
811 static void
813 {
814 tree ns;
816 /* DR 275: An explicit instantiation shall appear in an enclosing
817 namespace of its template. */
823 }
825 // Returns the type of a template specialization only if that
826 // specialization needs to be defined. Otherwise (e.g., if the type has
827 // already been defined), the function returns NULL_TREE.
828 static tree
830 {
831 // An implicit instantiation of an incomplete type implies
832 // the definition of a new class template.
833 //
834 // template<typename T>
835 // struct S;
836 //
837 // template<typename T>
838 // struct S<T*>;
839 //
840 // Here, S<T*> is an implicit instantiation of S whose type
841 // is incomplete.
845 // It can also be the case that TYPE is a completed specialization.
846 // Continuing the previous example, suppose we also declare:
847 //
848 // template<typename T>
849 // requires Integral<T>
850 // struct S<T*>;
851 //
852 // Here, S<T*> refers to the specialization S<T*> defined
853 // above. However, we need to differentiate definitions because
854 // we intend to define a new partial specialization. In this case,
855 // we rely on the fact that the constraints are different for
856 // this declaration than that above.
857 //
858 // Note that we also get here for injected class names and
859 // late-parsed template definitions. We must ensure that we
860 // do not create new type declarations for those cases.
862 {
866 // If there are no template parameters, this cannot be a new
867 // partial template specializtion?
871 // The injected-class-name is not a new partial specialization.
875 // If the constraints are not the same as those of the primary
876 // then, we can probably create a new specialization.
880 {
884 }
886 // Also, if there's a pre-existing specialization with matching
887 // constraints, then this also isn't new.
890 {
898 }
900 // Create a new type node (and corresponding type decl)
901 // for the newly declared specialization.
906 /* We only need a separate type node for storing the definition of this
907 partial specialization; uses of S<T*> are unconstrained, so all are
908 equivalent. So keep TYPE_CANONICAL the same. */
911 // Build the corresponding type decl.
917 }
920 }
922 /* The TYPE is being declared. If it is a template type, that means it
923 is a partial specialization. Do appropriate error-checking. */
925 tree
927 {
928 tree context;
933 /* A lambda that appears in specialization context is not itself a
934 specialization. */
939 {
943 }
948 {
954 else
957 }
959 {
960 /* This is for ordinary explicit specialization and partial
961 specialization of a template class such as:
963 template <> class C<int>;
965 or:
967 template <class T> class C<T*>;
969 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
972 {
979 {
984 }
985 }
991 /* Trying to define a specialization either without a template<> header
992 or in an inappropriate place. We've already given an error, so just
993 bail now so we don't actually define the specialization. */
995 }
1001 {
1002 /* This is for an explicit specialization of member class
1003 template according to [temp.expl.spec/18]:
1005 template <> template <class U> class C<int>::D;
1007 The context `C<int>' must be an implicit instantiation.
1008 Otherwise this is just a member class template declared
1009 earlier like:
1011 template <> class C<int> { template <class U> class D; };
1012 template <> template <class U> class C<int>::D;
1014 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1015 while in the second case, `C<int>::D' is a primary template
1016 and `C<T>::D' may not exist. */
1020 {
1021 tree t;
1026 {
1031 }
1033 /* Check for invalid specialization after instantiation:
1035 template <> template <> class C<int>::D<int>;
1036 template <> template <class U> class C<int>::D; */
1040 {
1044 {
1045 /* We already have a full specialization of this partial
1046 instantiation, or a full specialization has been
1047 looked up but not instantiated. Reassign it to the
1048 new member specialization template. */
1049 spec_entry elt;
1061 spec_entry **slot
1066 }
1067 else
1068 /* But if we've had an implicit instantiation, that's a
1069 problem ([temp.expl.spec]/6). */
1072 }
1074 /* Mark TYPE as a specialization. And as a result, we only
1075 have one level of template argument for the innermost
1076 class template. */
1081 }
1082 }
1084 {
1085 /* Someday C++0x may allow for enum template specialization. */
1090 else
1091 {
1094 }
1095 }
1098 }
1100 /* Returns nonzero if we can optimize the retrieval of specializations
1101 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1102 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1106 {
1109 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1110 parameter. */
1112 /* The optimized lookup depends on the fact that the
1113 template arguments for the member function template apply
1114 purely to the containing class, which is not true if the
1115 containing class is an explicit or partial
1116 specialization. */
1120 /* It is possible to have a template that is not a member
1121 template and is not a member of a template class:
1123 template <typename T>
1124 struct S { friend A::f(); };
1126 Here, the friend function is a template, but the context does
1127 not have template information. The optimized lookup relies
1128 on having ARGS be the template arguments for both the class
1129 and the function template. */
1131 }
1133 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1134 gone through coerce_template_parms by now. */
1136 static void
1138 {
1141 {
1144 {
1151 /* Allow typedefs on the type of a non-type argument, since a
1153 else
1155 }
1156 }
1158 }
1160 /* Retrieve the specialization (in the sense of [temp.spec] - a
1161 specialization is either an instantiation or an explicit
1162 specialization) of TMPL for the given template ARGS. If there is
1163 no such specialization, return NULL_TREE. The ARGS are a vector of
1164 arguments, or a vector of vectors of arguments, in the case of
1165 templates with more than one level of parameters.
1167 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1168 then we search for a partial specialization matching ARGS. This
1169 parameter is ignored if TMPL is not a class template.
1171 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1172 result is a NONTYPE_ARGUMENT_PACK. */
1174 static tree
1176 {
1186 /* There should be as many levels of arguments as there are
1187 levels of parameters. */
1196 /* Lambda functions in templates aren't instantiated normally, but through
1197 tsubst_lambda_expr. */
1202 {
1203 /* The template arguments actually apply to the containing
1204 class. Find the class specialization with those
1205 arguments. */
1207 tree class_specialization
1212 /* Find the instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. ATTRLIST is the list of
1477 attributes that the specialization is declared with or NULL when
1478 it isn't. Returns SPEC, or an equivalent prior declaration, if
1479 available.
1481 We also store instantiations of field packs in the hash table, even
1482 though they are not themselves templates, to make lookup easier. */
1484 static tree
1486 hashval_t hash)
1487 {
1488 tree fn;
1490 spec_entry elt;
1498 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1499 register it; we want the corresponding TEMPLATE_DECL instead.
1500 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1501 the more obvious `uses_template_parms (spec)' to avoid problems
1502 with default function arguments. In particular, given
1503 something like this:
1505 template <class T> void f(T t1, T t = T())
1507 the default argument expression is not substituted for in an
1508 instantiation unless and until it is actually needed. */
1512 /* We don't put these specializations in the hash table, but we might
1513 want to give an error about a mismatch. */
1515 else
1516 {
1524 slot =
1528 else
1530 }
1532 /* We can sometimes try to re-register a specialization that we've
1533 already got. In particular, regenerate_decl_from_template calls
1534 duplicate_decls which will update the specialization list. But,
1535 we'll still get called again here anyhow. It's more convenient
1536 to simply allow this than to try to prevent it. */
1540 {
1542 {
1545 {
1547 fn);
1549 }
1550 else
1551 {
1552 tree clone;
1553 /* This situation should occur only if the first
1554 specialization is an implicit instantiation, the
1555 second is an explicit specialization, and the
1556 implicit instantiation has not yet been used. That
1557 situation can occur if we have implicitly
1558 instantiated a member function and then specialized
1559 it later.
1561 We can also wind up here if a friend declaration that
1562 looked like an instantiation turns out to be a
1563 specialization:
1565 template <class T> void foo(T);
1566 class S { friend void foo<>(int) };
1567 template <> void foo(int);
1569 We transform the existing DECL in place so that any
1570 pointers to it become pointers to the updated
1571 declaration.
1573 If there was a definition for the template, but not
1574 for the specialization, we want this to look as if
1575 there were no definition, and vice versa. */
1578 /* The call to duplicate_decls will have applied
1579 [temp.expl.spec]:
1581 An explicit specialization of a function template
1582 is inline only if it is explicitly declared to be,
1583 and independently of whether its function template
1584 is.
1586 to the primary function; now copy the inline bits to
1587 the various clones. */
1589 {
1596 }
1600 }
1601 }
1603 {
1606 /* We've already complained in duplicate_decls. */
1610 /* Dup decl failed, but this is a new definition. Set the
1611 line number so any errors match this new
1612 definition. */
1616 }
1617 }
1621 /* A specialization must be declared in the same namespace as the
1622 template it is specializing. */
1628 {
1637 /* If TMPL is a forward declaration of a template function, keep a list
1638 of all specializations in case we need to reassign them to a friend
1639 template later in tsubst_friend_function.
1641 Also keep a list of all variable template instantiations so that
1642 process_partial_specialization can check whether a later partial
1643 specialization would have used it. */
1646 }
1649 }
1651 /* Returns true iff two spec_entry nodes are equivalent. */
1655 bool
1657 {
1664 /* tmpl could be a FIELD_DECL for a capture pack. */
1668 {
1669 /* Partial specializations of a variable template can be distinguished by
1670 constraints. */
1674 }
1678 }
1680 /* Returns a hash for a template TMPL and template arguments ARGS. */
1682 static hashval_t
1684 {
1687 }
1689 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1690 ignoring SPEC. */
1692 hashval_t
1694 {
1696 }
1698 /* Recursively calculate a hash value for a template argument ARG, for use
1699 in the hash tables of template specializations. */
1701 hashval_t
1703 {
1723 {
1731 {
1736 }
1758 {
1762 {
1765 }
1767 }
1771 {
1774 }
1785 val = iterative_hash_template_arg
1797 val);
1799 val);
1808 /* A lambda can't appear in a template arg, but don't crash on
1809 erroneous input. */
1821 /* Now hash operands as usual. */
1826 }
1829 {
1832 {
1833 // We want an alias specialization that survived strip_typedefs
1834 // to hash differently from its TYPE_CANONICAL, to avoid hash
1835 // collisions that compare as different in template_args_equal.
1836 // These could be dependent specializations that strip_typedefs
1837 // left alone, or untouched specializations because
1838 // coerce_template_parms returns the unconverted template
1839 // arguments if it sees incomplete argument packs.
1842 }
1845 val);
1848 /* Otherwise just compare the types during lookup. */
1857 {
1862 }
1863 }
1866 }
1868 /* Unregister the specialization SPEC as a specialization of TMPL.
1869 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1870 if the SPEC was listed as a specialization of TMPL.
1872 Note that SPEC has been ggc_freed, so we can't look inside it. */
1874 bool
1876 {
1878 spec_entry elt;
1886 {
1891 }
1894 }
1896 /* Like register_specialization, but for local declarations. We are
1897 registering SPEC, an instantiation of TMPL. */
1899 void
1901 {
1904 }
1906 /* TYPE is a class type. Returns true if TYPE is an explicitly
1907 specialized class. */
1909 bool
1911 {
1915 }
1917 /* Print the list of functions at FNS, going through all the overloads
1918 for each element of the list. Alternatively, FNS can not be a
1919 TREE_LIST, in which case it will be printed together with all the
1920 overloads.
1922 MORE and *STR should respectively be FALSE and NULL when the function
1923 is called from the outside. They are used internally on recursive
1924 calls. print_candidates manages the two parameters and leaves NULL
1925 in *STR when it ends. */
1927 static void
1929 {
1933 else
1935 {
1941 {
1944 else
1947 }
1949 }
1950 }
1952 /* Print the list of candidate FNS in an error message. FNS can also
1953 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1955 void
1957 {
1961 }
1963 /* Get a (possibly) constrained template declaration for the
1964 purpose of ordering candidates. */
1965 static tree
1967 {
1973 }
1975 /* Among candidates having the same signature, return the
1976 most constrained or NULL_TREE if there is no best candidate.
1977 If the signatures of candidates vary (e.g., template
1978 specialization vs. member function), then there can be no
1979 most constrained.
1981 Note that we don't compare constraints on the functions
1982 themselves, but rather those of their templates. */
1983 static tree
1985 {
1986 // Try to find the best candidate in a first pass.
1989 {
1996 }
1998 // Verify that the champ is better than previous candidates.
2003 }
2006 }
2009 /* Returns the template (one of the functions given by TEMPLATE_ID)
2010 which can be specialized to match the indicated DECL with the
2011 explicit template args given in TEMPLATE_ID. The DECL may be
2012 NULL_TREE if none is available. In that case, the functions in
2013 TEMPLATE_ID are non-members.
2015 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2016 specialization of a member template.
2018 The TEMPLATE_COUNT is the number of references to qualifying
2019 template classes that appeared in the name of the function. See
2020 check_explicit_specialization for a more accurate description.
2022 TSK indicates what kind of template declaration (if any) is being
2023 declared. TSK_TEMPLATE indicates that the declaration given by
2024 DECL, though a FUNCTION_DECL, has template parameters, and is
2025 therefore a template function.
2027 The template args (those explicitly specified and those deduced)
2028 are output in a newly created vector *TARGS_OUT.
2030 If it is impossible to determine the result, an error message is
2031 issued. The error_mark_node is returned to indicate failure. */
2033 static tree
2035 tree decl,
2039 tmpl_spec_kind tsk)
2040 {
2041 tree fns;
2042 tree targs;
2043 tree explicit_targs;
2046 /* A TREE_LIST of templates of which DECL may be a specialization.
2047 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2048 corresponding TREE_PURPOSE is the set of template arguments that,
2049 when used to instantiate the template, would produce a function
2050 with the signature of DECL. */
2060 /* We shouldn't be specializing a member template of an
2061 unspecialized class template; we already gave an error in
2062 check_specialization_scope, now avoid crashing. */
2066 {
2069 }
2077 /* Check for baselinks. */
2082 {
2085 }
2087 {
2090 }
2092 /* Count the number of template headers specified for this
2093 specialization. */
2103 {
2106 tf_warning_or_error,
2110 }
2112 {
2116 {
2117 tree decl_arg_types;
2118 tree fn_arg_types;
2119 tree insttype;
2121 /* In case of explicit specialization, we need to check if
2122 the number of template headers appearing in the specialization
2123 is correct. This is usually done in check_explicit_specialization,
2124 but the check done there cannot be exhaustive when specializing
2125 member functions. Consider the following code:
2127 template <> void A<int>::f(int);
2128 template <> template <> void A<int>::f(int);
2130 Assuming that A<int> is not itself an explicit specialization
2131 already, the first line specializes "f" which is a non-template
2132 member function, whilst the second line specializes "f" which
2133 is a template member function. So both lines are syntactically
2134 correct, and check_explicit_specialization does not reject
2135 them.
2137 Here, we can do better, as we are matching the specialization
2138 against the declarations. We count the number of template
2139 headers, and we check if they match TEMPLATE_COUNT + 1
2140 (TEMPLATE_COUNT is the number of qualifying template classes,
2141 plus there must be another header for the member template
2142 itself).
2144 Notice that if header_count is zero, this is not a
2145 specialization but rather a template instantiation, so there
2146 is no check we can perform here. */
2150 /* Check that the number of template arguments at the
2151 innermost level for DECL is the same as for FN. */
2159 /* DECL might be a specialization of FN. */
2163 /* For a non-static member function, we need to make sure
2164 that the const qualification is the same. Since
2165 get_bindings does not try to merge the "this" parameter,
2166 we must do the comparison explicitly. */
2168 {
2173 /* And the ref-qualification. */
2177 }
2179 /* Skip the "this" parameter and, for constructors of
2180 classes with virtual bases, the VTT parameter. A
2181 full specialization of a constructor will have a VTT
2182 parameter, but a template never will. */
2183 decl_arg_types
2185 fn_arg_types
2188 /* Function templates cannot be specializations; there are
2189 no partial specializations of functions. Therefore, if
2190 the type of DECL does not match FN, there is no
2191 match.
2193 Note that it should never be the case that we have both
2194 candidates added here, and for regular member functions
2195 below. */
2197 {
2201 }
2203 /* See whether this function might be a specialization of this
2204 template. Suppress access control because we might be trying
2205 to make this specialization a friend, and we have already done
2206 access control for the declaration of the specialization. */
2212 /* We cannot deduce template arguments that when used to
2213 specialize TMPL will produce DECL. */
2217 /* We deduced something involving 'auto', which isn't a valid
2218 template argument. */
2221 /* Remove, from the set of candidates, all those functions
2222 whose constraints are not satisfied. */
2226 // Then, try to form the new function type.
2230 fn_arg_types
2235 /* Save this template, and the arguments deduced. */
2237 }
2239 /* FN is an ordinary member function, and we need a
2240 specialization of a member template. */
2241 ;
2243 /* We can get IDENTIFIER_NODEs here in certain erroneous
2244 cases. */
2245 ;
2247 /* This is just an ordinary non-member function. Nothing can
2248 be a specialization of that. */
2249 ;
2251 /* Cannot specialize functions that are created implicitly. */
2252 ;
2253 else
2254 {
2255 tree decl_arg_types;
2257 /* This is an ordinary member function. However, since
2258 we're here, we can assume its enclosing class is a
2259 template class. For example,
2261 template <typename T> struct S { void f(); };
2262 template <> void S<int>::f() {}
2264 Here, S<int>::f is a non-template, but S<int> is a
2265 template class. If FN has the same type as DECL, we
2266 might be in business. */
2269 /* Its enclosing class is an explicit specialization
2270 of a template class. This is not a candidate. */
2275 /* The return types differ. */
2278 /* Adjust the type of DECL in case FN is a static member. */
2285 decl_arg_types))
2293 // If the deduced arguments do not satisfy the constraints,
2294 // this is not a candidate.
2298 // Add the candidate.
2300 }
2301 }
2304 {
2305 /* We have:
2307 [temp.expl.spec]
2309 It is possible for a specialization with a given function
2310 signature to be instantiated from more than one function
2311 template. In such cases, explicit specification of the
2312 template arguments must be used to uniquely identify the
2313 function template specialization being specialized.
2315 Note that here, there's no suggestion that we're supposed to
2316 determine which of the candidate templates is most
2317 specialized. However, we, also have:
2319 [temp.func.order]
2321 Partial ordering of overloaded function template
2322 declarations is used in the following contexts to select
2323 the function template to which a function template
2324 specialization refers:
2326 -- when an explicit specialization refers to a function
2327 template.
2329 So, we do use the partial ordering rules, at least for now.
2330 This extension can only serve to make invalid programs valid,
2331 so it's safe. And, there is strong anecdotal evidence that
2332 the committee intended the partial ordering rules to apply;
2333 the EDG front end has that behavior, and John Spicer claims
2334 that the committee simply forgot to delete the wording in
2335 [temp.expl.spec]. */
2338 {
2341 }
2342 }
2344 // Concepts allows multiple declarations of member functions
2345 // with the same signature. Like above, we need to rely on
2346 // on the partial ordering of those candidates to determine which
2347 // is the best.
2349 {
2351 {
2354 }
2355 }
2358 {
2365 else
2368 }
2372 {
2378 }
2380 /* We have one, and exactly one, match. */
2382 {
2386 // Propagate the candidate's constraints to the declaration.
2389 /* DECL is a re-declaration or partial instantiation of a template
2390 function. */
2393 /* It was a specialization of an ordinary member function in a
2394 template class. */
2396 }
2398 /* It was a specialization of a template. */
2401 {
2406 }
2407 else
2410 }
2412 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2413 but with the default argument values filled in from those in the
2414 TMPL_TYPES. */
2416 static tree
2418 tree tmpl_types)
2419 {
2420 tree new_spec_types;
2428 /* Substitute into the rest of the list. */
2429 new_spec_types =
2433 /* Add the default argument for this parameter. */
2436 new_spec_types);
2437 }
2439 /* DECL is an explicit specialization. Replicate default arguments
2440 from the template it specializes. (That way, code like:
2442 template <class T> void f(T = 3);
2443 template <> void f(double);
2444 void g () { f (); }
2446 works, as required.) An alternative approach would be to look up
2447 the correct default arguments at the call-site, but this approach
2448 is consistent with how implicit instantiations are handled. */
2450 static void
2452 {
2453 tree tmpl;
2454 tree spec_types;
2455 tree tmpl_types;
2456 tree new_spec_types;
2457 tree old_type;
2458 tree new_type;
2459 tree t;
2464 /* See if there's anything we need to do. */
2477 {
2478 /* Remove the this pointer, but remember the object's type for
2479 CV quals. */
2485 {
2486 /* DECL may contain more parameters than TMPL due to the extra
2487 in-charge parameter in constructors and destructors. */
2490 }
2492 {
2495 }
2496 }
2498 /* Compute the merged default arguments. */
2499 new_spec_types =
2502 /* Compute the new FUNCTION_TYPE. */
2504 {
2508 new_spec_types);
2511 /* Put the in-charge parameter back. */
2514 new_spec_types);
2518 new_spec_types);
2519 }
2520 else
2522 new_spec_types);
2532 }
2534 /* Return the number of template headers we expect to see for a definition
2535 or specialization of CTYPE or one of its non-template members. */
2537 int
2539 {
2543 {
2544 /* You're supposed to have one `template <...>' for every
2545 template class, but you don't need one for a full
2546 specialization. For example:
2548 template <class T> struct S{};
2549 template <> struct S<int> { void f(); };
2550 void S<int>::f () {}
2552 is correct; there shouldn't be a `template <>' for the
2553 definition of `S<int>::f'. */
2555 /* If CTYPE does not have template information of any
2556 kind, then it is not a template, nor is it nested
2557 within a template. */
2565 }
2568 }
2570 /* Do a simple sanity check on the template headers that precede the
2571 variable declaration DECL. */
2573 void
2575 {
2580 {
2583 "variable templates only available with "
2586 // Namespace-scope variable templates should have a template header.
2588 }
2590 {
2592 "too many template headers for %qD "
2598 "members of an explicitly specialized class are defined "
2600 }
2601 }
2603 /* An explicit specialization whose declarator-id or class-head-name is not
2604 qualified shall be declared in the nearest enclosing namespace of the
2605 template, or, if the namespace is inline (7.3.1), any namespace from its
2606 enclosing namespace set.
2608 If the name declared in the explicit instantiation is an unqualified name,
2609 the explicit instantiation shall appear in the namespace where its template
2610 is declared or, if that namespace is inline (7.3.1), any namespace from its
2611 enclosing namespace set. */
2613 void
2615 {
2620 {
2626 /* This was allowed in C++98, so only pedwarn. */
2628 "outside its namespace must use a nested-name-"
2630 }
2631 }
2633 /* Warn for a template specialization SPEC that is missing some of a set
2634 of function or type attributes that the template TEMPL is declared with.
2635 ATTRLIST is a list of additional attributes that SPEC should be taken
2636 to ultimately be declared with. */
2638 static void
2640 {
2647 /* Avoid warning if either declaration or its type is deprecated. */
2669 /* Avoid warning if the primary has no attributes. */
2673 /* Avoid warning if either declaration contains an attribute on
2674 the white list below. */
2677 };
2685 /* Avoid warning if the difference between the primary and
2686 the specialization is not in one of the attributes below. */
2690 };
2692 /* Put together a list of the black listed attributes that the primary
2693 template is declared with that the specialization is not, in case
2694 it's not apparent from the most recent declaration of the primary. */
2696 pretty_printer str;
2699 {
2701 {
2706 {
2716 }
2717 }
2718 }
2725 spec))
2731 }
2733 /* Check to see if the function just declared, as indicated in
2734 DECLARATOR, and in DECL, is a specialization of a function
2735 template. We may also discover that the declaration is an explicit
2736 instantiation at this point.
2738 Returns DECL, or an equivalent declaration that should be used
2739 instead if all goes well. Issues an error message if something is
2740 amiss. Returns error_mark_node if the error is not easily
2741 recoverable.
2743 FLAGS is a bitmask consisting of the following flags:
2745 2: The function has a definition.
2746 4: The function is a friend.
2748 The TEMPLATE_COUNT is the number of references to qualifying
2749 template classes that appeared in the name of the function. For
2750 example, in
2752 template <class T> struct S { void f(); };
2753 void S<int>::f();
2755 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2756 classes are not counted in the TEMPLATE_COUNT, so that in
2758 template <class T> struct S {};
2759 template <> struct S<int> { void f(); }
2760 template <> void S<int>::f();
2762 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2763 invalid; there should be no template <>.)
2765 If the function is a specialization, it is marked as such via
2766 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2767 is set up correctly, and it is added to the list of specializations
2768 for that template. */
2770 tree
2772 tree decl,
2775 tree attrlist)
2776 {
2785 tmpl_spec_kind tsk;
2788 {
2791 else
2793 }
2794 else
2798 {
2801 {
2804 }
2806 {
2808 /* This could be something like:
2810 template <class T> void f(T);
2811 class S { friend void f<>(int); } */
2813 else
2814 {
2815 /* This case handles bogus declarations like template <>
2816 template <class T> void f<int>(); */
2819 declarator);
2821 }
2822 }
2826 /* The error has already been reported in
2827 check_specialization_scope. */
2833 /* Fall through. */
2846 decl);
2849 else
2853 /* Fall through. */
2859 /* In cases like template<> constexpr bool v = true;
2860 We'll give an error in check_template_variable. */
2866 else
2872 {
2873 /* This case handles bogus declarations like template <>
2874 template <class T> void f<int>(); */
2878 declarator);
2880 {
2881 /* Partial specialization of variable template. */
2885 }
2889 else
2893 ok:;
2894 }
2897 /* This is a specialization of a member template, without
2898 specialization the containing class. Something like:
2900 template <class T> struct S {
2901 template <class U> void f (U);
2902 };
2903 template <> template <class U> void S<int>::f(U) {}
2905 That's a specialization -- but of the entire template. */
2911 }
2914 /* This doesn't apply to variable templates. */
2917 {
2921 {
2925 }
2926 }
2929 {
2934 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2936 {
2937 tree fns;
2942 else
2943 {
2944 /* If there is no class context, the explicit instantiation
2945 must be at namespace scope. */
2948 /* Find the namespace binding, using the declaration
2949 context. */
2953 /* If lookup fails, look for a friend declaration so we can
2954 give a better diagnostic. */
2960 {
2963 }
2964 }
2967 }
2973 {
2975 /* A specialization in class scope. This is invalid,
2976 but the error will already have been flagged by
2977 check_specialization_scope. */
2979 else
2980 {
2981 /* It's not valid to write an explicit instantiation in
2982 class scope, e.g.:
2984 class C { template void f(); }
2986 This case is caught by the parser. However, on
2987 something like:
2989 template class C { void f(); };
2991 (which is invalid) we can get here. The error will be
2992 issued later. */
2993 ;
2994 }
2997 }
3000 {
3001 // We'll match variable templates in start_decl.
3005 /* Find the list of functions in ctype that have the same
3006 name as the declared function. */
3010 {
3014 {
3015 /* From [temp.expl.spec]:
3017 If such an explicit specialization for the member
3018 of a class template names an implicitly-declared
3019 special member function (clause _special_), the
3020 program is ill-formed.
3022 Similar language is found in [temp.explicit]. */
3025 }
3028 }
3030 /* For a type-conversion operator, We might be looking for
3031 `operator int' which will be a specialization of
3032 `operator T'. Grab all the conversion operators, and
3033 then select from them. */
3038 {
3041 }
3042 else
3044 }
3046 /* Figure out what exactly is being specialized at this point.
3047 Note that for an explicit instantiation, even one for a
3048 member function, we cannot tell a priori whether the
3049 instantiation is for a member template, or just a member
3050 function of a template class. Even if a member template is
3051 being instantiated, the member template arguments may be
3052 elided if they can be deduced from the rest of the
3053 declaration. */
3056 member_specialization,
3057 template_count,
3058 tsk);
3061 /* We couldn't figure out what this declaration was
3062 specializing. */
3064 else
3065 {
3068 {
3070 "friend declaration %qD is not visible to "
3074 }
3082 {
3083 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3084 is done by do_decl_instantiation later. */
3090 {
3091 /* If TMPL is not the most general template (for
3092 example, if TMPL is a friend template that is
3093 injected into namespace scope), then there will
3094 be too many levels of TARGS. Remove some of them
3095 here. */
3097 tree new_targs;
3104 }
3107 }
3109 /* If we thought that the DECL was a member function, but it
3110 turns out to be specializing a static member function,
3111 make DECL a static member function as well. */
3117 /* If this is a specialization of a member template of a
3118 template class, we want to return the TEMPLATE_DECL, not
3119 the specialization of it. */
3121 {
3126 {
3127 tree parm;
3131 /* We want to use the argument list specified in the
3132 definition, not in the original declaration. */
3137 }
3140 }
3142 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3148 /* Inherit default function arguments from the template
3149 DECL is specializing. */
3153 /* This specialization has the same protection as the
3154 template it specializes. */
3158 /* 7.1.1-1 [dcl.stc]
3160 A storage-class-specifier shall not be specified in an
3161 explicit specialization...
3163 The parser rejects these, so unless action is taken here,
3164 explicit function specializations will always appear with
3165 global linkage.
3167 The action recommended by the C++ CWG in response to C++
3168 defect report 605 is to make the storage class and linkage
3169 of the explicit specialization match the templated function:
3171 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3172 */
3174 {
3178 /* A concept cannot be specialized. */
3180 {
3182 gen_tmpl);
3184 }
3186 /* This specialization has the same linkage and visibility as
3187 the function template it specializes. */
3190 {
3193 }
3196 {
3199 }
3200 }
3202 /* If DECL is a friend declaration, declared using an
3203 unqualified name, the namespace associated with DECL may
3204 have been set incorrectly. For example, in:
3206 template <typename T> void f(T);
3207 namespace N {
3208 struct S { friend void f<int>(int); }
3209 }
3211 we will have set the DECL_CONTEXT for the friend
3212 declaration to N, rather than to the global namespace. */
3217 /* This is not really a declaration of a specialization.
3218 It's just the name of an instantiation. But, it's not
3219 a request for an instantiation, either. */
3222 /* A specialization is not necessarily COMDAT. */
3228 /* If this is a full specialization, register it so that we can find
3229 it again. Partial specializations will be registered in
3230 process_partial_specialization. */
3232 {
3237 }
3240 /* A 'structor should already have clones. */
3246 }
3247 }
3250 }
3252 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3253 parameters. These are represented in the same format used for
3254 DECL_TEMPLATE_PARMS. */
3256 int
3258 {
3259 const_tree p1;
3260 const_tree p2;
3268 {
3280 {
3284 /* If either of the template parameters are invalid, assume
3285 they match for the sake of error recovery. */
3298 }
3299 }
3302 /* One set of parameters has more parameters lists than the
3303 other. */
3307 }
3309 /* Determine whether PARM is a parameter pack. */
3311 bool
3313 {
3314 /* Determine if we have a non-type template parameter pack. */
3321 /* If this is a list of template parameters, we could get a
3322 TYPE_DECL or a TEMPLATE_DECL. */
3326 /* Otherwise it must be a type template parameter. */
3330 }
3332 /* Determine if T is a function parameter pack. */
3334 bool
3336 {
3340 }
3342 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3343 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3345 tree
3347 {
3354 }
3356 /* Return true iff the function parameter PARAM_DECL was expanded
3357 from the function parameter pack PACK. */
3359 bool
3361 {
3366 /* The parameter pack and its pack arguments have the same
3367 DECL_PARM_INDEX. */
3369 }
3371 /* Determine whether ARGS describes a variadic template args list,
3372 i.e., one that is terminated by a template argument pack. */
3374 static bool
3376 {
3378 tree last_parm;
3392 }
3394 /* Generate a new name for the parameter pack name NAME (an
3395 IDENTIFIER_NODE) that incorporates its */
3397 static tree
3399 {
3400 /* Munge the name to include the parameter index. */
3401 #define NUMBUF_LEN 128
3415 }
3417 /* Return true if T is a primary function, class or alias template
3418 specialization, not including the template pattern. */
3420 bool
3422 {
3438 }
3440 /* Return true if PARM is a template template parameter. */
3442 bool
3444 {
3446 }
3448 /* Return true iff PARM is a DECL representing a type template
3449 parameter. */
3451 bool
3453 {
3458 }
3460 /* Return the template parameters of T if T is a
3461 primary template instantiation, NULL otherwise. */
3463 tree
3465 {
3470 parms = INNERMOST_TEMPLATE_PARMS
3474 }
3476 /* Return the template parameters of the LEVELth level from the full list
3477 of template parameters PARMS. */
3479 tree
3481 {
3482 tree p;
3493 }
3495 /* Returns the template arguments of T if T is a template instantiation,
3496 NULL otherwise. */
3498 tree
3500 {
3508 }
3510 /* Return the argument pack elements of T if T is a template argument pack,
3511 NULL otherwise. */
3513 tree
3515 {
3521 }
3523 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3524 ARGUMENT_PACK_SELECT represents. */
3526 static tree
3528 {
3532 /* If the selected argument is an expansion E, that most likely means we were
3533 called from gen_elem_of_pack_expansion_instantiation during the
3534 substituting of an argument pack (of which the Ith element is a pack
3535 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3536 In this case, the Ith element resulting from this substituting is going to
3537 be a pack expansion, which pattern is the pattern of E. Let's return the
3538 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3539 resulting pack expansion from it. */
3541 {
3542 /* Make sure we aren't throwing away arg info. */
3545 }
3548 }
3551 /* True iff FN is a function representing a built-in variadic parameter
3552 pack. */
3554 bool
3556 {
3566 }
3568 /* True iff CALL is a call to a function representing a built-in variadic
3569 parameter pack. */
3571 static bool
3573 {
3577 }
3579 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3581 static tree
3583 tree in_decl)
3584 {
3590 {
3592 {
3595 }
3600 }
3601 else
3602 {
3606 /* Calculate the largest value of len that won't make the size of the vec
3607 overflow an int. The compiler will exceed resource limits long before
3608 this, but it seems a decent place to diagnose. */
3612 {
3617 }
3625 }
3626 }
3628 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3629 CALL. */
3631 static tree
3633 tree in_decl)
3634 {
3644 }
3646 /* Structure used to track the progress of find_parameter_packs_r. */
3647 struct find_parameter_pack_data
3648 {
3649 /* TREE_LIST that will contain all of the parameter packs found by
3650 the traversal. */
3653 /* Set of AST nodes that have been visited by the traversal. */
3656 /* True iff we're making a type pack expansion. */
3658 };
3660 /* Identifies all of the argument packs that occur in a template
3661 argument and appends them to the TREE_LIST inside DATA, which is a
3662 find_parameter_pack_data structure. This is a subroutine of
3663 make_pack_expansion and uses_parameter_packs. */
3664 static tree
3666 {
3672 /* Handle type aliases/typedefs. */
3674 {
3681 }
3683 /* Identify whether this is a parameter pack or not. */
3685 {
3693 /* FALLTHRU */
3695 /* If the placeholder appears in the decl-specifier-seq of a function
3696 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3697 is a pack expansion, the invented template parameter is a template
3698 parameter pack. */
3708 {
3709 /* We don't want to walk into the type of a PARM_DECL,
3710 because we don't want to see the type parameter pack. */
3713 }
3718 {
3719 /* We don't want to walk into the type of a variadic capture proxy,
3720 because we don't want to see the type parameter pack. */
3723 }
3725 {
3727 find_parameter_packs_r,
3730 }
3742 /* Not a parameter pack. */
3744 }
3747 {
3748 /* Add this parameter pack to the list. */
3750 }
3756 /* This switch statement will return immediately if we don't find a
3757 parameter pack. */
3759 {
3764 /* Check the template itself. */
3767 /* Check the template arguments. */
3781 /* Ignore the declaration of a capture proxy for a parameter pack. */
3789 /* Fall through. */
3834 {
3835 /* Look at explicit captures. */
3840 /* Since we defer implicit capture, look in the body as well. */
3846 }
3849 {
3850 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3851 type_pack_expansion_p to false so that any placeholders
3852 within the expression don't get marked as parameter packs. */
3860 }
3864 }
3867 }
3869 /* Determines if the expression or type T uses any parameter packs. */
3870 bool
3872 {
3881 }
3883 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3884 representation a base-class initializer into a parameter pack
3885 expansion. If all goes well, the resulting node will be an
3886 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3887 respectively. */
3888 tree
3890 {
3891 tree result;
3900 {
3901 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3902 class initializer. In this case, the TREE_PURPOSE will be a
3903 _TYPE node (representing the base class expansion we're
3904 initializing) and the TREE_VALUE will be a TREE_LIST
3905 containing the initialization arguments.
3907 The resulting expansion looks somewhat different from most
3908 expansions. Rather than returning just one _EXPANSION, we
3909 return a TREE_LIST whose TREE_PURPOSE is a
3910 TYPE_PACK_EXPANSION containing the bases that will be
3911 initialized. The TREE_VALUE will be identical to the
3912 original TREE_VALUE, which is a list of arguments that will
3913 be passed to each base. We do not introduce any new pack
3914 expansion nodes into the TREE_VALUE (although it is possible
3915 that some already exist), because the TREE_PURPOSE and
3916 TREE_VALUE all need to be expanded together with the same
3917 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3918 resulting TREE_PURPOSE will mention the parameter packs in
3919 both the bases and the arguments to the bases. */
3920 tree purpose;
3921 tree value;
3924 /* Determine which parameter packs will be used by the base
3925 class expansion. */
3934 {
3937 arg);
3940 }
3943 {
3944 /* Collect the sets of parameter packs used in each of the
3945 initialization arguments. */
3947 {
3948 /* Determine which parameter packs will be expanded in this
3949 argument. */
3952 }
3953 }
3957 /* Create the pack expansion type for the base type. */
3963 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3964 they will rarely be compared to anything. */
3968 }
3973 /* Build the PACK_EXPANSION_* node. */
3974 result = for_types
3979 {
3980 /* Propagate type and const-expression information. */
3983 /* Mark this read now, since the expansion might be length 0. */
3985 }
3986 else
3987 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3988 they will rarely be compared to anything. */
3991 /* Determine which parameter packs will be expanded. */
3998 /* Make sure we found some parameter packs. */
4000 {
4002 {
4005 else
4007 }
4009 }
4015 }
4017 /* Checks T for any "bare" parameter packs, which have not yet been
4018 expanded, and issues an error if any are found. This operation can
4019 only be done on full expressions or types (e.g., an expression
4020 statement, "if" condition, etc.), because we could have expressions like:
4022 foo(f(g(h(args)))...)
4024 where "args" is a parameter pack. check_for_bare_parameter_packs
4025 should not be called for the subexpressions args, h(args),
4026 g(h(args)), or f(g(h(args))), because we would produce erroneous
4027 error messages.
4029 Returns TRUE and emits an error if there were bare parameter packs,
4030 returns FALSE otherwise. */
4031 bool
4033 {
4040 /* A lambda might use a parameter pack from the containing context. */
4054 {
4058 {
4069 else
4074 else
4078 }
4081 }
4084 }
4086 /* Expand any parameter packs that occur in the template arguments in
4087 ARGS. */
4088 tree
4090 {
4099 /* First, determine if we need to expand anything, and the number of
4100 slots we'll need. */
4102 {
4107 {
4111 else
4113 }
4114 else
4115 {
4117 num_result_args++;
4118 }
4119 }
4121 /* If no expansion is necessary, we're done. */
4125 /* Expand arguments. */
4128 non_default_args_count =
4131 {
4134 {
4141 }
4142 else
4143 {
4146 }
4147 }
4151 }
4153 /* Checks if DECL shadows a template parameter.
4155 [temp.local]: A template-parameter shall not be redeclared within its
4156 scope (including nested scopes).
4158 Emits an error and returns TRUE if the DECL shadows a parameter,
4159 returns FALSE otherwise. */
4161 bool
4163 {
4164 tree olddecl;
4166 /* If we're not in a template, we can't possibly shadow a template
4167 parameter. */
4171 /* Figure out what we're shadowing. */
4175 /* If there's no previous binding for this name, we're not shadowing
4176 anything, let alone a template parameter. */
4180 /* If we're not shadowing a template parameter, we're done. Note
4181 that OLDDECL might be an OVERLOAD (or perhaps even an
4182 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4183 node. */
4187 /* We check for decl != olddecl to avoid bogus errors for using a
4188 name inside a class. We check TPFI to avoid duplicate errors for
4189 inline member templates. */
4195 /* Don't complain about the injected class name, as we've already
4196 complained about the class itself. */
4203 else
4208 }
4210 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4211 ORIG_LEVEL, DECL, and TYPE. */
4213 static tree
4217 tree decl,
4218 tree type)
4219 {
4230 }
4232 /* Find the canonical type parameter for the given template type
4233 parameter. Returns the canonical type parameter, which may be TYPE
4234 if no such parameter existed. */
4236 static tree
4238 {
4239 tree list;
4253 else
4254 {
4258 }
4259 }
4261 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4262 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4263 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4264 new one is created. */
4266 static tree
4268 tsubst_flags_t complain)
4269 {
4274 {
4293 /* Template template parameters need this. */
4295 {
4302 }
4303 }
4306 }
4308 /* Process information from new template parameter PARM and append it
4309 to the LIST being built. This new parameter is a non-type
4310 parameter iff IS_NON_TYPE is true. This new parameter is a
4311 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4312 is in PARM_LOC. */
4314 tree
4317 {
4326 {
4330 {
4334 else
4336 }
4339 }
4342 {
4348 {
4349 /* [temp.param]
4351 The top-level cv-qualifiers on the template-parameter are
4352 ignored when determining its type. */
4357 && !is_parameter_pack
4358 /* If we're in a nested template parameter list, the template
4359 template parameter could be a parameter pack. */
4361 {
4362 /* This template parameter is not a parameter pack, but it
4363 should be. Complain about "bare" parameter packs. */
4366 /* Recover by calling this a parameter pack. */
4368 }
4369 }
4371 /* A template parameter is not modifiable. */
4380 processing_template_decl,
4385 }
4386 else
4387 {
4388 tree t;
4392 {
4394 /* This is for distinguishing between real templates and template
4395 template parameters */
4399 }
4400 else
4401 {
4403 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4406 }
4413 processing_template_decl,
4417 }
4421 /* Build requirements for the type/template parameter.
4422 This must be done after SET_DECL_TEMPLATE_PARM_P or
4423 process_template_parm could fail. */
4428 /* Build the parameter node linking the parameter declaration,
4429 its default argument (if any), and its constraints (if any). */
4434 }
4436 /* The end of a template parameter list has been reached. Process the
4437 tree list into a parameter vector, converting each parameter into a more
4438 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4439 as PARM_DECLs. */
4441 tree
4443 {
4448 /* Pop the dummy parameter level and add the real one. */
4451 current_template_parms
4456 {
4460 }
4465 }
4467 // Explicitly indicate the end of the template parameter list. We assume
4468 // that the current template parameters have been constructed and/or
4469 // managed explicitly, as when creating new template template parameters
4470 // from a shorthand constraint.
4471 void
4473 {
4475 }
4477 /* end_template_decl is called after a template declaration is seen. */
4479 void
4481 {
4487 /* This matches the pushlevel in begin_template_parm_list. */
4492 }
4494 /* Takes a TREE_LIST representing a template parameter and convert it
4495 into an argument suitable to be passed to the type substitution
4496 functions. Note that If the TREE_LIST contains an error_mark
4497 node, the returned argument is error_mark_node. */
4499 tree
4501 {
4514 {
4518 {
4519 /* Turn this argument into a TYPE_ARGUMENT_PACK
4520 with a single element, which expands T. */
4529 }
4530 }
4531 else
4532 {
4536 {
4537 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4538 with a single element, which expands T. */
4548 }
4549 else
4551 }
4553 }
4555 /* Given a single level of template parameters (a TREE_VEC), return it
4556 as a set of template arguments. */
4558 static tree
4560 {
4570 }
4572 /* Given a set of template parameters, return them as a set of template
4573 arguments. The template parameters are represented as a TREE_VEC, in
4574 the form documented in cp-tree.h for template arguments. */
4576 static tree
4578 {
4579 tree header;
4584 /* If there is only one level of template parameters, we do not
4585 create a TREE_VEC of TREE_VECs. Instead, we return a single
4586 TREE_VEC containing the arguments. */
4591 {
4596 else
4598 }
4601 }
4603 /* Within the declaration of a template, return the currently active
4604 template parameters as an argument TREE_VEC. */
4606 static tree
4608 {
4610 }
4612 /* Update the declared TYPE by doing any lookups which were thought to be
4613 dependent, but are not now that we know the SCOPE of the declarator. */
4615 tree
4617 {
4628 /* Don't bother building up the args in this case. */
4630 {
4631 /* tsubst in the args corresponding to the template parameters,
4632 including auto if present. Most things will be unchanged, but
4633 make_typename_type and tsubst_qualified_id will resolve
4634 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4637 tree pushed;
4639 {
4643 }
4648 }
4654 {
4657 else
4659 }
4661 }
4663 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4664 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4665 the new template is a member template. */
4667 tree
4669 {
4677 }
4679 struct template_parm_data
4680 {
4681 /* The level of the template parameters we are currently
4682 processing. */
4685 /* The index of the specialization argument we are currently
4686 processing. */
4689 /* An array whose size is the number of template parameters. The
4690 elements are nonzero if the parameter has been used in any one
4691 of the arguments processed so far. */
4694 /* An array whose size is the number of template arguments. The
4695 elements are nonzero if the argument makes use of template
4696 parameters of this level. */
4698 };
4700 /* Subroutine of push_template_decl used to see if each template
4701 parameter in a partial specialization is used in the explicit
4702 argument list. If T is of the LEVEL given in DATA (which is
4703 treated as a template_parm_data*), then DATA->PARMS is marked
4704 appropriately. */
4706 static int
4708 {
4716 {
4719 }
4721 /* In C++17 the type of a non-type argument is a deduced context. */
4726 data,
4727 NULL,
4730 /* Return zero so that for_each_template_parm will continue the
4731 traversal of the tree; we want to mark *every* template parm. */
4733 }
4735 /* Process the partial specialization DECL. */
4737 static tree
4739 {
4746 tree inner_parms;
4747 tree inst;
4757 /* A concept cannot be specialized. */
4759 {
4762 }
4767 /* We check that each of the template parameters given in the
4768 partial specialization is used in the argument list to the
4769 specialization. For example:
4771 template <class T> struct S;
4772 template <class T> struct S<T*>;
4774 The second declaration is OK because `T*' uses the template
4775 parameter T, whereas
4777 template <class T> struct S<int>;
4779 is no good. Even trickier is:
4781 template <class T>
4782 struct S1
4783 {
4784 template <class U>
4785 struct S2;
4786 template <class U>
4787 struct S2<T>;
4788 };
4790 The S2<T> declaration is actually invalid; it is a
4791 full-specialization. Of course,
4793 template <class U>
4794 struct S2<T (*)(U)>;
4796 or some such would have been OK. */
4804 {
4809 NULL,
4811 }
4814 {
4815 /* One of the template parms was not used in a deduced context in the
4816 specialization. */
4818 {
4822 }
4826 }
4831 /* [temp.class.spec]
4833 The argument list of the specialization shall not be identical to
4834 the implicit argument list of the primary template. */
4835 tree main_args
4838 && (!flag_concepts
4841 {
4844 "any template arguments; to define the primary template, "
4846 else
4848 "template arguments and is not more constrained than "
4849 "the primary template; to define the primary template, "
4852 }
4854 /* A partial specialization that replaces multiple parameters of the
4855 primary template with a pack expansion is less specialized for those
4856 parameters. */
4858 {
4860 "primary template because it replaces multiple parameters "
4863 /* Avoid crash in process_partial_specialization. */
4865 }
4867 /* If we aren't in a dependent class, we can actually try deduction. */
4869 /* FIXME we should be able to handle a partial specialization of a
4870 partial instantiation, but currently we can't (c++/41727). */
4873 {
4877 maintmpl);
4878 }
4880 /* [temp.class.spec]
4882 A partially specialized non-type argument expression shall not
4883 involve template parameters of the partial specialization except
4884 when the argument expression is a simple identifier.
4886 The type of a template parameter corresponding to a specialized
4887 non-type argument shall not be dependent on a parameter of the
4888 specialization.
4890 Also, we verify that pack expansions only occur at the
4891 end of the argument list. */
4895 {
4902 {
4903 /* Extract the arguments from the argument pack. We'll be
4904 iterating over these in the following loop. */
4907 }
4910 {
4912 /* Get the Jth argument in the parameter pack. */
4916 {
4917 /* Pack expansions must come at the end of the
4918 argument list. */
4921 {
4925 else
4928 }
4929 }
4932 /* We only care about the pattern. */
4938 /* This next two lines are the `argument expression is not just a
4939 simple identifier' condition and also the `specialized
4940 non-type argument' bit. */
4944 {
4948 arg);
4949 else
4950 {
4951 /* Look at the corresponding template parameter,
4952 marking which template parameters its type depends
4953 upon. */
4957 {
4958 /* We haven't yet initialized TPD2. Do so now. */
4960 /* The number of parameters here is the number in the
4961 main template, which, as checked in the assertion
4962 above, is NARGS. */
4966 }
4968 /* Mark the template parameters. But this time, we're
4969 looking for the template parameters of the main
4970 template, not in the specialization. */
4977 NULL,
4981 {
4982 /* The type depended on some template parameters.
4983 If they are fully specialized in the
4984 specialization, that's OK. */
4993 "type %qT of template argument %qE depends "
4995 "type %qT of template argument %qE depends "
4997 type,
4998 arg);
4999 }
5000 }
5001 }
5002 }
5003 }
5005 /* We should only get here once. */
5009 // Build the template decl.
5018 /* Give template template parms a DECL_CONTEXT of the template
5019 for which they are a parameter. */
5021 {
5025 }
5028 /* We didn't register this in check_explicit_specialization so we could
5029 wait until the constraints were set. */
5031 else
5041 {
5047 {
5055 "declaration of %qD ambiguates earlier template "
5059 "partial specialization of %qD after instantiation "
5061 }
5062 }
5065 }
5067 /* PARM is a template parameter of some form; return the corresponding
5068 TEMPLATE_PARM_INDEX. */
5070 static tree
5072 {
5085 }
5087 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5088 parameter packs used by the template parameter PARM. */
5090 static void
5092 {
5093 /* A type parm can't refer to another parm. */
5097 {
5101 }
5108 }
5110 /* PARM is a template parameter pack. Return any parameter packs used in
5111 its type or the type of any of its template parameters. If there are
5112 any such packs, it will be instantiated into a fixed template parameter
5113 list by partial instantiation rather than be fully deduced. */
5115 tree
5117 {
5118 /* This can only be true in a member template. */
5121 /* This can only be true for a parameter pack. */
5124 /* A type parm can't refer to another parm. */
5138 }
5140 /* Check that a template declaration's use of default arguments and
5141 parameter packs is not invalid. Here, PARMS are the template
5142 parameters. IS_PRIMARY is true if DECL is the thing declared by
5143 a primary template. IS_PARTIAL is true if DECL is a partial
5144 specialization.
5146 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5147 function template declaration or a friend class template
5148 declaration. In the function case, 1 indicates a declaration, 2
5149 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5150 emitted for extraneous default arguments.
5152 Returns TRUE if there were no errors found, FALSE otherwise. */
5154 bool
5157 {
5160 tree parm_level;
5163 /* [temp.param]
5165 A default template-argument shall not be specified in a
5166 function template declaration or a function template definition, nor
5167 in the template-parameter-list of the definition of a member of a
5168 class template. */
5172 /* You can't have a function template declaration in a local
5173 scope, nor you can you define a member of a class template in a
5174 local scope. */
5182 /* A lambda doesn't have an explicit declaration; don't complain
5183 about the parms of the enclosing class. */
5190 /* If this is either a friend defined in the scope of the class
5191 or a member function. */
5197 /* And, if it was a member function, it really was defined in
5198 the scope of the class. */
5201 /* We already checked these parameters when the template was
5202 declared, so there's no need to do it again now. This function
5203 was defined in class scope, but we're processing its body now
5204 that the class is complete. */
5207 /* Core issue 226 (C++0x only): the following only applies to class
5208 templates. */
5211 {
5212 /* [temp.param]
5214 If a template-parameter has a default template-argument, all
5215 subsequent template-parameters shall have a default
5216 template-argument supplied. */
5218 {
5225 {
5235 {
5237 /* For better subsequent error-recovery, we indicate that
5238 there should have been a default argument. */
5241 }
5243 && !is_friend_decl
5244 /* Don't complain about an enclosing partial
5245 specialization. */
5250 /* A fixed parameter pack will be partially
5251 instantiated into a fixed length list. */
5253 {
5254 /* A primary class template can only have one
5255 parameter pack, at the end of the template
5256 parameter list. */
5264 }
5265 }
5266 }
5267 }
5270 || is_partial
5271 || !is_primary
5273 /* For an ordinary class template, default template arguments are
5274 allowed at the innermost level, e.g.:
5275 template <class T = int>
5276 struct S {};
5277 but, in a partial specialization, they're not allowed even
5278 there, as we have in [temp.class.spec]:
5280 The template parameter list of a specialization shall not
5281 contain default template argument values.
5283 So, for a partial specialization, or for a function template
5284 (in C++98/C++03), we look at all of them. */
5285 ;
5286 else
5287 /* But, for a primary class template that is not a partial
5288 specialization we look at all template parameters except the
5289 innermost ones. */
5292 /* Figure out what error message to issue. */
5307 else
5308 /* Per [temp.param]/9, "A default template-argument shall not be
5309 specified in the template-parameter-lists of the definition of
5310 a member of a class template that appears outside of the member's
5311 class.", thus if we aren't handling a member of a class template
5312 there is no need to examine the parameters. */
5316 /* If we're inside a class definition, there's no need to
5317 examine the parameters to the class itself. On the one
5318 hand, they will be checked when the class is defined, and,
5319 on the other, default arguments are valid in things like:
5320 template <class T = double>
5321 struct S { template <class U> void f(U); };
5322 Here the default argument for `S' has no bearing on the
5323 declaration of `f'. */
5325 else
5326 /* Check everything. */
5332 {
5339 {
5344 {
5346 {
5353 }
5355 /* Clear out the default argument so that we are not
5356 confused later. */
5358 }
5359 }
5361 /* At this point, if we're still interested in issuing messages,
5362 they must apply to classes surrounding the object declared. */
5366 }
5369 }
5371 /* Worker for push_template_decl_real, called via
5372 for_each_template_parm. DATA is really an int, indicating the
5373 level of the parameters we are interested in. If T is a template
5374 parameter of that level, return nonzero. */
5376 static int
5378 {
5384 else
5387 }
5389 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5390 DATA is really an int, indicating the innermost outer level of parameters.
5391 If T is a template parameter of that level or further out, return
5392 nonzero. */
5394 static int
5396 {
5402 else
5405 }
5407 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5408 parameters given by current_template_args, or reuses a
5409 previously existing one, if appropriate. Returns the DECL, or an
5410 equivalent one, if it is replaced via a call to duplicate_decls.
5412 If IS_FRIEND is true, DECL is a friend declaration. */
5414 tree
5416 {
5417 tree tmpl;
5418 tree args;
5419 tree info;
5420 tree ctx;
5424 /* True if the template is a member template, in the sense of
5425 [temp.mem]. */
5431 /* See if this is a partial specialization. */
5444 /* For a friend, we want the context of the friend, not
5445 the type of which it is a friend. */
5449 /* In the case of a virtual function, we want the class in which
5450 it is defined. */
5452 else
5453 /* Otherwise, if we're currently defining some class, the DECL
5454 is assumed to be a member of the class. */
5463 /* See if this is a primary template. */
5466 /* A friend template that specifies a class context, i.e.
5467 template <typename T> friend void A<T>::f();
5468 is not primary. */
5473 else
5477 {
5484 {
5487 }
5489 {
5491 {
5494 }
5496 {
5497 /* [temp.mem]
5499 A destructor shall not be a member template. */
5502 }
5509 {
5510 /* [basic.stc.dynamic.allocation]
5512 An allocation function can be a function
5513 template. ... Template allocation functions shall
5514 have two or more parameters. */
5517 }
5518 }
5521 {
5522 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5525 {
5531 }
5532 }
5535 /* alias-declaration */
5539 else
5540 {
5543 }
5544 }
5546 /* Check to see that the rules regarding the use of default
5547 arguments are not being violated. We check args for a friend
5548 functions when we know whether it's a definition, introducing
5549 declaration or re-declaration. */
5554 /* Ensure that there are no parameter packs in the type of this
5555 declaration that have not been expanded. */
5557 {
5558 /* Check each of the arguments individually to see if there are
5559 any bare parameter packs. */
5565 {
5568 {
5569 /* This is a PARM_DECL that contains unexpanded parameter
5570 packs. We have already complained about this in the
5571 check_for_bare_parameter_packs call, so just replace
5572 these types with ERROR_MARK_NODE. */
5575 }
5579 }
5581 /* Check for bare parameter packs in the return type and the
5582 exception specifiers. */
5584 /* Errors were already issued, set return type to int
5585 as the frontend doesn't expect error_mark_node as
5586 the return type. */
5590 }
5595 {
5598 }
5611 {
5616 /* If DECL is a TYPE_DECL for a class-template, then there won't
5617 be DECL_LANG_SPECIFIC. The information equivalent to
5618 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5622 {
5623 /* Since a template declaration already existed for this
5624 class-type, we must be redeclaring it here. Make sure
5625 that the redeclaration is valid. */
5627 current_template_parms,
5629 /* We don't need to create a new TEMPLATE_DECL; just use the
5630 one we already had. */
5632 }
5633 else
5634 {
5636 member_template_p);
5641 {
5642 /* A specialization of a member template of a template
5643 class. */
5647 }
5648 }
5649 }
5650 else
5651 {
5657 {
5660 }
5668 {
5669 tree new_tmpl;
5671 /* The declaration is a specialization of a member
5672 template, declared outside the class. Therefore, the
5673 innermost template arguments will be NULL, so we
5674 replace them with the arguments determined by the
5675 earlier call to check_explicit_specialization. */
5678 new_tmpl
5680 member_template_p);
5690 args,
5693 }
5695 /* Make sure the template headers we got make sense. */
5700 {
5705 }
5706 else
5708 {
5713 {
5717 else
5721 /* Avoid crash in import_export_decl. */
5724 }
5729 /* Can happen in erroneous input. */
5731 else
5733 }
5735 /* Check that the parms are used in the appropriate qualifying scopes
5736 in the declarator. */
5740 {
5746 /* Avoid crash in import_export_decl. */
5749 }
5750 }
5755 /* Push template declarations for global functions and types. Note
5756 that we do not try to push a global template friend declared in a
5757 template class; such a thing may well depend on the template
5758 parameters of the class. */
5761 {
5766 /* Hide template friend classes that haven't been declared yet. */
5768 {
5771 }
5772 }
5775 {
5780 /* Give template template parms a DECL_CONTEXT of the template
5781 for which they are a parameter. */
5784 {
5788 }
5794 }
5796 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5797 back to its most general template. If TMPL is a specialization,
5798 ARGS may only have the innermost set of arguments. Add the missing
5799 argument levels if necessary. */
5807 else
5808 {
5813 }
5816 && !is_friend
5819 /* Set DECL_COMDAT on template instantiations; if we force
5820 them to be emitted by explicit instantiation or -frepo,
5821 mark_needed will tell cgraph to do the right thing. */
5825 }
5827 tree
5829 {
5831 }
5833 /* FN is an inheriting constructor that inherits from the constructor
5834 template INHERITED; turn FN into a constructor template with a matching
5835 template header. */
5837 tree
5839 {
5840 tree inner_parms
5843 tree parms
5854 }
5856 /* Called when a class template TYPE is redeclared with the indicated
5857 template PARMS, e.g.:
5859 template <class T> struct S;
5860 template <class T> struct S {}; */
5862 bool
5864 {
5865 tree tmpl;
5866 tree tmpl_parms;
5870 {
5873 }
5877 /* The type is nested in some template class. Nothing to worry
5878 about here; there are no new template parameters for the nested
5879 type. */
5883 {
5885 tmpl);
5887 }
5893 {
5903 }
5906 {
5907 tree tmpl_parm;
5908 tree parm;
5909 tree tmpl_default;
5910 tree parm_default;
5924 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5925 TEMPLATE_DECL. */
5935 {
5939 }
5942 {
5943 /* We have in [temp.param]:
5945 A template-parameter may not be given default arguments
5946 by two different declarations in the same scope. */
5951 }
5954 /* Update the previous template parameters (which are the ones
5955 that will really count) with the new default value. */
5958 /* Update the new parameters, too; they'll be used as the
5959 parameters for any members. */
5962 /* Give each template template parm in this redeclaration a
5963 DECL_CONTEXT of the template for which they are a parameter. */
5965 {
5968 }
5972 }
5974 // Cannot redeclare a class template with a different set of constraints.
5976 {
5981 }
5984 }
5986 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5987 to be used when the caller has already checked
5988 (processing_template_decl
5989 && !instantiation_dependent_expression_p (expr)
5990 && potential_constant_expression (expr))
5991 and cleared processing_template_decl. */
5993 tree
5995 {
5998 complain,
6002 }
6004 /* Simplify EXPR if it is a non-dependent expression. Returns the
6005 (possibly simplified) expression. */
6007 tree
6009 {
6013 /* If we're in a template, but EXPR isn't value dependent, simplify
6014 it. We're supposed to treat:
6016 template <typename T> void f(T[1 + 1]);
6017 template <typename T> void f(T[2]);
6019 as two declarations of the same function, for example. */
6022 {
6023 processing_template_decl_sentinel s;
6025 }
6027 }
6029 tree
6031 {
6033 }
6035 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6036 an uninstantiated expression. */
6038 tree
6040 {
6044 {
6047 else
6048 {
6049 processing_template_decl_sentinel s;
6051 }
6052 }
6054 }
6056 /* True iff T is a specialization of a variable template. */
6058 bool
6060 {
6065 }
6067 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6068 template declaration, or a TYPE_DECL for an alias declaration. */
6070 bool
6072 {
6080 }
6082 /* Return TRUE iff T is a specialization of an alias template. */
6084 bool
6086 {
6087 /* It's an alias template specialization if it's an alias and its
6088 TYPE_NAME is a specialization of a primary template. */
6094 }
6096 /* An alias template is complex from a SFINAE perspective if a template-id
6097 using that alias can be ill-formed when the expansion is not, as with
6098 the void_t template. We determine this by checking whether the
6099 expansion for the alias template uses all its template parameters. */
6101 struct uses_all_template_parms_data
6102 {
6105 };
6107 static int
6109 {
6117 }
6119 static bool
6121 {
6136 }
6138 /* Return TRUE iff T is a specialization of a complex alias template with
6139 dependent template-arguments. */
6141 bool
6143 {
6156 }
6158 /* Return the number of innermost template parameters in TMPL. */
6160 static int
6162 {
6165 }
6167 /* Return either TMPL or another template that it is equivalent to under DR
6168 1286: An alias that just changes the name of a template is equivalent to
6169 the other template. */
6171 static tree
6173 {
6176 {
6177 /* Determine if the alias is equivalent to an underlying template. */
6189 tree alias_args = INNERMOST_TEMPLATE_ARGS
6194 /* Alias is equivalent. Strip it and repeat. */
6196 }
6199 }
6201 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6202 must be a reference-to-function or a pointer-to-function type, as specified
6203 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6204 and check that the resulting function has external linkage. */
6206 static tree
6208 tsubst_flags_t complain)
6209 {
6212 linkage_kind linkage;
6227 /* [temp.arg.nontype]/1
6229 A template-argument for a non-type, non-template template-parameter
6230 shall be one of:
6231 [...]
6232 -- the address of an object or function with external [C++11: or
6233 internal] linkage. */
6236 {
6238 {
6244 else
6247 }
6249 }
6253 {
6255 {
6260 else
6264 }
6266 }
6268 accept:
6270 {
6273 else
6275 }
6280 }
6282 /* Subroutine of convert_nontype_argument.
6283 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6284 Emit an error otherwise. */
6286 static bool
6288 tsubst_flags_t complain)
6289 {
6306 {
6311 else
6313 }
6315 }
6317 /* Returns TRUE iff the address of OP is value-dependent.
6319 14.6.2.4 [temp.dep.temp]:
6320 A non-integral non-type template-argument is dependent if its type is
6321 dependent or it has either of the following forms
6322 qualified-id
6323 & qualified-id
6324 and contains a nested-name-specifier which specifies a class-name that
6325 names a dependent type.
6327 We generalize this to just say that the address of a member of a
6328 dependent class is value-dependent; the above doesn't cover the
6329 address of a static data member named with an unqualified-id. */
6331 static bool
6333 {
6334 /* We could use get_inner_reference here, but there's no need;
6335 this is only relevant for template non-type arguments, which
6336 can only be expressed as &id-expression. */
6338 {
6342 }
6345 }
6347 /* The next set of functions are used for providing helpful explanatory
6348 diagnostics for failed overload resolution. Their messages should be
6349 indented by two spaces for consistency with the messages in
6350 call.c */
6352 static int
6354 {
6356 }
6358 /* Other failure functions should call this one, to provide a single function
6359 for setting a breakpoint on. */
6361 static int
6363 {
6365 }
6367 static int
6369 {
6374 }
6376 static int
6378 {
6384 }
6386 static int
6388 {
6392 }
6394 static int
6396 {
6399 " template parameter %qD is not a parameter pack, but "
6403 }
6405 static int
6407 {
6410 " template argument %qE does not match "
6414 }
6416 static int
6418 {
6422 }
6424 static int
6426 {
6432 }
6434 static int
6436 {
6438 {
6443 else
6445 " deduced conflicting values for non-type parameter "
6447 }
6449 }
6451 static int
6453 {
6456 " variable-sized array type %qT is not "
6458 arg);
6460 }
6462 static int
6464 {
6468 arg);
6470 }
6472 static int
6474 {
6476 {
6482 else
6487 }
6489 }
6491 static int
6493 {
6495 }
6497 static int
6500 {
6502 }
6504 static int
6507 {
6513 }
6515 static int
6518 {
6521 {
6529 }
6531 }
6533 static int
6535 {
6538 " template parameters of a template template argument are "
6541 }
6543 static int
6545 {
6551 }
6553 static int
6555 {
6560 }
6562 /* Attempt to convert the non-type template parameter EXPR to the
6563 indicated TYPE. If the conversion is successful, return the
6564 converted value. If the conversion is unsuccessful, return
6565 NULL_TREE if we issued an error message, or error_mark_node if we
6566 did not. We issue error messages for out-and-out bad template
6567 parameters, but not simply because the conversion failed, since we
6568 might be just trying to do argument deduction. Both TYPE and EXPR
6569 must be non-dependent.
6571 The conversion follows the special rules described in
6572 [temp.arg.nontype], and it is much more strict than an implicit
6573 conversion.
6575 This function is called twice for each template argument (see
6576 lookup_template_class for a more accurate description of this
6577 problem). This means that we need to handle expressions which
6578 are not valid in a C++ source, but can be created from the
6579 first call (for instance, casts to perform conversions). These
6580 hacks can go away after we fix the double coercion problem. */
6582 static tree
6584 {
6585 tree expr_type;
6589 /* Detect immediately string literals as invalid non-type argument.
6590 This special-case is not needed for correctness (we would easily
6591 catch this later), but only to provide better diagnostic for this
6592 common user mistake. As suggested by DR 100, we do not mention
6593 linkage issues in the diagnostic as this is not the point. */
6594 /* FIXME we're making this OK. */
6596 {
6602 }
6604 /* Add the ADDR_EXPR now for the benefit of
6605 value_dependent_expression_p. */
6608 {
6612 }
6614 /* If we are in a template, EXPR may be non-dependent, but still
6615 have a syntactic, rather than semantic, form. For example, EXPR
6616 might be a SCOPE_REF, rather than the VAR_DECL to which the
6617 SCOPE_REF refers. Preserving the qualifying scope is necessary
6618 so that access checking can be performed when the template is
6619 instantiated -- but here we need the resolved form so that we can
6620 convert the argument. */
6632 /* If the argument is non-dependent, perform any conversions in
6633 non-dependent context as well. */
6641 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6642 to a non-type argument of "nullptr". */
6646 /* In C++11, integral or enumeration non-type template arguments can be
6647 arbitrary constant expressions. Pointer and pointer to
6648 member arguments can be general constant expressions that evaluate
6649 to a null value, but otherwise still need to be of a specific form. */
6651 {
6653 /* A PTRMEM_CST is already constant, and a valid template
6654 argument for a parameter of pointer to member type, we just want
6655 to leave it in that form rather than lower it to a
6659 {
6660 /* C++17: A template-argument for a non-type template-parameter shall
6661 be a converted constant expression (8.20) of the type of the
6662 template-parameter. */
6668 }
6670 {
6675 }
6676 }
6680 else
6683 /* HACK: Due to double coercion, we can get a
6684 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6685 which is the tree that we built on the first call (see
6686 below when coercing to reference to object or to reference to
6687 function). We just strip everything and get to the arg.
6688 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6689 for examples. */
6691 {
6697 {
6698 /* ??? Maybe we could use convert_from_reference here, but we
6699 would need to relax its constraints because the NOP_EXPR
6700 could actually change the type to something more cv-qualified,
6701 and this is not folded by convert_from_reference. */
6706 && (same_type_ignoring_top_level_qualifiers_p
6709 {
6712 }
6713 }
6714 }
6716 /* [temp.arg.nontype]/5, bullet 1
6718 For a non-type template-parameter of integral or enumeration type,
6719 integral promotions (_conv.prom_) and integral conversions
6720 (_conv.integral_) are applied. */
6722 {
6724 {
6729 }
6734 /* Notice that there are constant expressions like '4 % 0' which
6735 do not fold into integer constants. */
6738 {
6740 {
6744 else
6750 /* else cxx_constant_value complained but gave us
6751 a real constant, so go ahead. */
6753 {
6754 /* Some assemble time constant expressions like
6755 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6756 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6757 as we can emit them into .rodata initializers of
6758 variables, yet they can't fold into an INTEGER_CST at
6759 compile time. Refuse them here. */
6764 }
6765 }
6766 else
6768 }
6770 /* Avoid typedef problems. */
6773 }
6774 /* [temp.arg.nontype]/5, bullet 2
6776 For a non-type template-parameter of type pointer to object,
6777 qualification conversions (_conv.qual_) and the array-to-pointer
6778 conversion (_conv.array_) are applied. */
6780 {
6783 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6784 decay_conversion or an explicit cast. If it's a problematic cast,
6785 we'll complain about it below. */
6787 {
6792 {
6795 }
6796 }
6798 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6800 A template-argument for a non-type, non-template template-parameter
6801 shall be one of: [...]
6803 -- the name of a non-type template-parameter;
6804 -- the address of an object or function with external linkage, [...]
6805 expressed as "& id-expression" where the & is optional if the name
6806 refers to a function or array, or if the corresponding
6807 template-parameter is a reference.
6809 Here, we do not care about functions, as they are invalid anyway
6810 for a parameter of type pointer-to-object. */
6813 /* Non-type template parameters are OK. */
6814 ;
6818 {
6820 {
6823 "because %qD is a variable, not the address of "
6826 }
6828 {
6834 }
6835 /* Other values, like integer constants, might be valid
6836 non-type arguments of some other type. */
6838 }
6839 else
6840 {
6844 {
6849 }
6851 {
6857 }
6860 {
6865 }
6866 /* C++17: For a non-type template-parameter of reference or pointer
6867 type, the value of the constant expression shall not refer to (or
6868 for a pointer type, shall not be the address of):
6869 * a subobject (4.5),
6870 * a temporary object (15.2),
6871 * a string literal (5.13.5),
6872 * the result of a typeid expression (8.2.8), or
6873 * a predefined __func__ variable (11.4.1). */
6875 {
6878 decl);
6880 }
6884 {
6889 }
6891 {
6895 decl);
6897 }
6898 }
6905 }
6906 /* [temp.arg.nontype]/5, bullet 3
6908 For a non-type template-parameter of type reference to object, no
6909 conversions apply. The type referred to by the reference may be more
6910 cv-qualified than the (otherwise identical) type of the
6911 template-argument. The template-parameter is bound directly to the
6912 template-argument, which must be an lvalue. */
6914 {
6916 expr_type))
6920 {
6925 }
6928 {
6933 }
6935 /* [temp.arg.nontype]/1
6937 A template-argument for a non-type, non-template template-parameter
6938 shall be one of: [...]
6940 -- the address of an object or function with external linkage. */
6943 {
6946 {
6949 "because a reference variable does not have a constant "
6952 }
6953 }
6957 /* OK, dependent reference. We don't want to ask whether a DECL is
6959 else
6960 {
6962 {
6968 }
6970 /* DR 1155 allows internal linkage in C++11 and up. */
6973 {
6979 }
6982 }
6986 }
6987 /* [temp.arg.nontype]/5, bullet 4
6989 For a non-type template-parameter of type pointer to function, only
6990 the function-to-pointer conversion (_conv.func_) is applied. If the
6991 template-argument represents a set of overloaded functions (or a
6992 pointer to such), the matching function is selected from the set
6993 (_over.over_). */
6995 {
6996 /* If the argument is a template-id, we might not have enough
6997 context information to decay the pointer. */
6999 {
7003 }
7006 /* Null pointer values are OK in C++11. */
7012 }
7013 /* [temp.arg.nontype]/5, bullet 5
7015 For a non-type template-parameter of type reference to function, no
7016 conversions apply. If the template-argument represents a set of
7017 overloaded functions, the matching function is selected from the set
7018 (_over.over_). */
7020 {
7022 {
7024 {
7029 }
7031 }
7036 }
7037 /* [temp.arg.nontype]/5, bullet 6
7039 For a non-type template-parameter of type pointer to member function,
7040 no conversions apply. If the template-argument represents a set of
7041 overloaded member functions, the matching member function is selected
7042 from the set (_over.over_). */
7044 {
7049 /* [temp.arg.nontype] bullet 1 says the pointer to member
7050 expression must be a pointer-to-member constant. */
7055 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7056 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7059 }
7060 /* [temp.arg.nontype]/5, bullet 7
7062 For a non-type template-parameter of type pointer to data member,
7063 qualification conversions (_conv.qual_) are applied. */
7065 {
7066 /* [temp.arg.nontype] bullet 1 says the pointer to member
7067 expression must be a pointer-to-member constant. */
7075 }
7077 {
7079 {
7084 }
7086 }
7087 /* A template non-type parameter must be one of the above. */
7088 else
7091 /* Sanity check: did we actually convert the argument to the
7092 right type? */
7096 }
7098 /* Subroutine of coerce_template_template_parms, which returns 1 if
7099 PARM_PARM and ARG_PARM match using the rule for the template
7100 parameters of template template parameters. Both PARM and ARG are
7101 template parameters; the rest of the arguments are the same as for
7102 coerce_template_template_parms.
7103 */
7104 static int
7106 tree arg,
7107 tsubst_flags_t complain,
7108 tree in_decl,
7109 tree outer_args)
7110 {
7119 {
7121 /* We encounter instantiations of templates like
7122 template <template <template <class> class> class TT>
7123 class C; */
7124 {
7131 }
7132 /* Fall through. */
7137 /* Argument is a parameter pack but parameter is not. */
7142 /* The tsubst call is used to handle cases such as
7144 template <int> class C {};
7145 template <class T, template <T> class TT> class D {};
7146 D<int, C> d;
7148 i.e. the parameter list of TT depends on earlier parameters. */
7150 {
7155 }
7159 /* Argument is a parameter pack but parameter is not. */
7166 }
7169 }
7171 /* Coerce template argument list ARGLIST for use with template
7172 template-parameter TEMPL. */
7174 static tree
7176 tsubst_flags_t complain)
7177 {
7178 /* Consider an example where a template template parameter declared as
7180 template <class T, class U = std::allocator<T> > class TT
7182 The template parameter level of T and U are one level larger than
7183 of TT. To proper process the default argument of U, say when an
7184 instantiation `TT<int>' is seen, we need to build the full
7185 arguments containing {int} as the innermost level. Outer levels,
7186 available when not appearing as default template argument, can be
7187 obtained from the arguments of the enclosing template.
7189 Suppose that TT is later substituted with std::vector. The above
7190 instantiation is `TT<int, std::allocator<T> >' with TT at
7191 level 1, and T at level 2, while the template arguments at level 1
7192 becomes {std::vector} and the inner level 2 is {int}. */
7196 {
7198 /* We want arguments for the partial specialization, not arguments for
7199 the primary template. */
7201 else
7203 }
7205 {
7206 /* This is an argument of the current template, so we haven't set
7207 DECL_CONTEXT yet. */
7208 tree relevant_template_parms;
7210 /* Parameter levels that are greater than the level of the given
7211 template template parm are irrelevant. */
7218 }
7225 complain,
7228 }
7230 /* A cache of template template parameters with match-all default
7231 arguments. */
7233 static void
7235 {
7239 }
7240 static tree
7242 {
7247 }
7249 /* T is a bound template template-parameter. Copy its arguments into default
7250 arguments of the template template-parameter's template parameters. */
7252 static tree
7254 {
7277 {
7280 {
7283 }
7284 }
7288 }
7290 /* ARG is a bound potential template template-argument, and PARGS is a list
7291 of arguments for the corresponding template template-parameter. Adjust
7292 PARGS as appropriate for application to ARG's template, and if ARG is a
7293 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7294 arguments to the template template parameter. */
7296 static tree
7298 {
7302 {
7303 /* When comparing two template template-parameters in partial ordering,
7304 rewrite the one currently being used as an argument to have default
7305 arguments for all parameters. */
7311 }
7312 else
7313 {
7314 tree aparms
7319 }
7322 }
7324 /* Subroutine of unify for the case when PARM is a
7325 BOUND_TEMPLATE_TEMPLATE_PARM. */
7327 static int
7330 {
7334 /* The template template parm might be variadic and the argument
7335 not, so flatten both argument lists. */
7340 {
7341 /* In keeping with P0522R0, adjust P's template arguments
7342 to apply to A's template; then flatten it again. */
7351 /* If the P0522 adjustment eliminated a pack expansion, deduce
7352 empty packs. */
7358 }
7359 else
7360 {
7361 /* Deduce arguments T, i from TT<T> or TT<i>.
7362 We check each element of PARMVEC and ARGVEC individually
7363 rather than the whole TREE_VEC since they can have
7364 different number of elements, which is allowed under N2555. */
7368 /* Check if the parameters end in a pack, making them
7369 variadic. */
7376 /* If the template argument list of P contains a pack
7377 expansion that is not the last template argument, the
7378 entire template argument list is a non-deduced
7379 context. */
7397 DEDUCE_EXACT,
7400 }
7403 }
7405 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7406 template template parameters. Both PARM_PARMS and ARG_PARMS are
7407 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7408 or PARM_DECL.
7410 Consider the example:
7411 template <class T> class A;
7412 template<template <class U> class TT> class B;
7414 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7415 the parameters to A, and OUTER_ARGS contains A. */
7417 static int
7419 tree arg_parms,
7420 tsubst_flags_t complain,
7421 tree in_decl,
7422 tree outer_args)
7423 {
7435 {
7436 /* P0522R0: A template template-parameter P is at least as specialized as
7437 a template template-argument A if, given the following rewrite to two
7438 function templates, the function template corresponding to P is at
7439 least as specialized as the function template corresponding to A
7440 according to the partial ordering rules for function templates
7441 ([temp.func.order]). Given an invented class template X with the
7442 template parameter list of A (including default arguments):
7444 * Each of the two function templates has the same template parameters,
7445 respectively, as P or A.
7447 * Each function template has a single function parameter whose type is
7448 a specialization of X with template arguments corresponding to the
7449 template parameters from the respective function template where, for
7450 each template parameter PP in the template parameter list of the
7451 function template, a corresponding template argument AA is formed. If
7452 PP declares a parameter pack, then AA is the pack expansion
7453 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7455 If the rewrite produces an invalid type, then P is not at least as
7456 specialized as A. */
7458 /* So coerce P's args to apply to A's parms, and then deduce between A's
7459 args and the converted args. If that succeeds, A is at least as
7460 specialized as P, so they match.*/
7467 {
7473 }
7474 }
7476 /* Determine whether we have a parameter pack at the end of the
7477 template template parameter's template parameter list. */
7479 {
7486 {
7500 }
7501 }
7507 /* Check all of the template parameters except the parameter pack at
7508 the end (if any). */
7510 {
7519 outer_args))
7522 }
7525 {
7526 /* Check each of the template parameters in the template
7527 argument against the template parameter pack at the end of
7528 the template template parameter. */
7535 {
7542 outer_args))
7544 }
7545 }
7548 }
7550 /* Verifies that the deduced template arguments (in TARGS) for the
7551 template template parameters (in TPARMS) represent valid bindings,
7552 by comparing the template parameter list of each template argument
7553 to the template parameter list of its corresponding template
7554 template parameter, in accordance with DR150. This
7555 routine can only be called after all template arguments have been
7556 deduced. It will return TRUE if all of the template template
7557 parameter bindings are okay, FALSE otherwise. */
7558 bool
7560 {
7564 /* We're dealing with template parms in this process. */
7570 {
7575 {
7580 {
7581 /* Look inside the argument pack. */
7584 }
7587 {
7591 /* Extract the next argument from the argument
7592 pack. */
7596 /* Look at the pattern of the pack expansion. */
7599 /* Extract the template parameters from the template
7600 argument. */
7606 /* Verify that we can coerce the template template
7607 parameters from the template argument to the template
7608 parameter. This requires an exact match. */
7610 && !coerce_template_template_parms
7612 targ_parms,
7613 tf_none,
7614 tparm,
7615 targs))
7616 {
7619 }
7620 }
7621 }
7622 }
7624 out:
7628 }
7630 /* Since type attributes aren't mangled, we need to strip them from
7631 template type arguments. */
7633 static tree
7635 {
7645 }
7647 /* And from inside dependent non-type arguments like sizeof(Type). */
7649 static tree
7651 {
7661 }
7663 // A template declaration can be substituted for a constrained
7664 // template template parameter only when the argument is more
7665 // constrained than the parameter.
7666 static bool
7668 {
7671 /* For now, allow constrained template template arguments
7672 and unconstrained template template parameters. */
7678 // If the template parameter is constrained, we need to rewrite its
7679 // constraints in terms of the ARG's template parameters. This ensures
7680 // that all of the template parameter types will have the same depth.
7681 //
7682 // Note that this is only valid when coerce_template_template_parm is
7683 // true for the innermost template parameters of PARM and ARG. In other
7684 // words, because coercion is successful, this conversion will be valid.
7686 {
7693 }
7696 }
7698 // Convert a placeholder argument into a binding to the original
7699 // parameter. The original parameter is saved as the TREE_TYPE of
7700 // ARG.
7703 {
7706 }
7708 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7709 because one of them is dependent. But we need to represent the
7710 conversion for the benefit of cp_tree_equal. */
7712 static tree
7714 {
7715 /* Auto parms get no conversion. */
7718 /* We don't need or want to add this conversion now if we're going to use the
7719 argument for deduction. */
7731 }
7733 /* Convert the indicated template ARG as necessary to match the
7734 indicated template PARM. Returns the converted ARG, or
7735 error_mark_node if the conversion was unsuccessful. Error and
7736 warning messages are issued under control of COMPLAIN. This
7737 conversion is for the Ith parameter in the parameter list. ARGS is
7738 the full set of template arguments deduced so far. */
7740 static tree
7742 tree arg,
7743 tree args,
7744 tsubst_flags_t complain,
7746 tree in_decl)
7747 {
7748 tree orig_arg;
7749 tree val;
7755 /* Trivially convert placeholders. */
7764 {
7765 /* The template argument was the name of some
7766 member function. That's usually
7767 invalid, but static members are OK. In any
7768 case, grab the underlying fields/functions
7769 and issue an error later if required. */
7772 }
7780 /* When determining whether an argument pack expansion is a template,
7781 look at the pattern. */
7785 /* Deal with an injected-class-name used as a template template arg. */
7787 {
7790 {
7800 }
7801 }
7803 is_tmpl_type =
7819 {
7821 {
7825 }
7828 "to refer to a type member of a template parameter, "
7833 typename_type,
7834 complain);
7837 }
7839 {
7841 {
7843 {
7855 else
7858 }
7859 }
7861 }
7863 {
7865 {
7872 else
7875 }
7877 }
7880 /* We already did the appropriate conversion when packing args. */
7883 {
7885 {
7887 /* The number of argument required is not known yet.
7888 Just accept it for now. */
7890 else
7891 {
7893 tree argparm;
7895 /* Strip alias templates that are equivalent to another
7896 template. */
7902 args))
7903 {
7906 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7907 TEMPLATE_DECL. */
7909 {
7914 }
7915 }
7916 else
7917 {
7919 {
7926 }
7929 }
7931 // Check that the constraints are compatible before allowing the
7932 // substitution.
7935 {
7937 {
7943 }
7945 }
7946 }
7947 }
7948 else
7950 /* We only form one instance of each template specialization.
7951 Therefore, if we use a non-canonical variant (i.e., a
7952 typedef), any future messages referring to the type will use
7953 the typedef, which is confusing if those future uses do not
7954 themselves also use the typedef. */
7957 }
7958 else
7959 {
7963 {
7967 }
7968 else
7976 /* We used to call digest_init here. However, digest_init
7977 will report errors, which we don't want when complain
7978 is zero. More importantly, digest_init will try too
7979 hard to convert things: for example, `0' should not be
7980 converted to pointer type at this point according to
7981 the standard. Accepting this is not merely an
7982 extension, since deciding whether or not these
7983 conversions can occur is part of determining which
7984 function template to call, or whether a given explicit
7985 argument specification is valid. */
7987 else
7988 {
7991 }
8001 {
8002 /* Reject template arguments that are references to built-in
8003 functions with no library fallbacks. */
8012 }
8015 {
8016 /* Strip typedefs from the SCOPE_REF. */
8019 complain);
8022 }
8023 }
8026 }
8028 /* Coerces the remaining template arguments in INNER_ARGS (from
8029 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8030 Returns the coerced argument pack. PARM_IDX is the position of this
8031 parameter in the template parameter list. ARGS is the original
8032 template argument list. */
8033 static tree
8036 tree args,
8037 tree inner_args,
8039 tree new_args,
8041 tree in_decl,
8042 tsubst_flags_t complain)
8043 {
8046 tree packed_args;
8047 tree argument_pack;
8054 {
8055 /* When the template parameter is a non-type template parameter pack
8056 or template template parameter pack whose type or template
8057 parameters use parameter packs, we know exactly how many arguments
8058 we are looking for. Build a vector of the instantiated decls for
8059 these template parameters in PACKED_PARMS. */
8060 /* We can't use make_pack_expansion here because it would interpret a
8061 _DECL as a use rather than a declaration. */
8075 /* If we're doing a partial instantiation of a member template,
8076 verify that all of the types used for the non-type
8077 template parameter pack are, in fact, valid for non-type
8078 template parameters. */
8081 {
8084 {
8088 }
8089 /* We don't know how many args we have yet, just
8090 use the unconverted ones for now. */
8092 }
8095 }
8096 /* Check if we have a placeholder pack, which indicates we're
8097 in the context of a introduction list. In that case we want
8098 to match this pack to the single placeholder. */
8102 {
8105 }
8106 else
8109 /* Convert the remaining arguments, which will be a part of the
8110 parameter pack "parm". */
8113 {
8119 {
8120 /* Once we've packed as many args as we have types, stop. */
8124 /* We don't know how many args we have yet, just
8125 use the unconverted ones for now. */
8127 else
8129 }
8132 {
8135 }
8136 else
8139 in_decl);
8143 }
8147 {
8152 }
8157 else
8158 {
8161 }
8168 }
8170 /* Returns the number of pack expansions in the template argument vector
8171 ARGS. */
8173 static int
8175 {
8180 {
8184 }
8186 }
8188 /* Convert all template arguments to their appropriate types, and
8189 return a vector containing the innermost resulting template
8190 arguments. If any error occurs, return error_mark_node. Error and
8191 warning messages are issued under control of COMPLAIN.
8193 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8194 for arguments not specified in ARGS. Otherwise, if
8195 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8196 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8197 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8198 ARGS. */
8200 static tree
8202 tree args,
8203 tree in_decl,
8204 tsubst_flags_t complain,
8207 {
8209 tree orig_inner_args;
8210 tree inner_args;
8211 tree new_args;
8212 tree new_inner_args;
8216 /* When used as a boolean value, indicates whether this is a
8217 variadic template parameter list. Since it's an int, we can also
8218 subtract it from nparms to get the number of non-variadic
8219 parameters. */
8224 /* Likewise for parameters with default arguments. */
8232 /* Determine if there are any parameter packs or default arguments. */
8234 {
8242 }
8245 /* If there are no parameters that follow a parameter pack, we need to
8246 expand any argument packs so that we can deduce a parameter pack from
8247 some non-packed args followed by an argument pack, as in variadic85.C.
8248 If there are such parameters, we need to leave argument packs intact
8249 so the arguments are assigned properly. This can happen when dealing
8250 with a nested class inside a partial specialization of a class
8251 template, as in variadic92.C, or when deducing a template parameter pack
8252 from a sub-declarator, as in variadic114.C. */
8256 /* Count any pack expansion args. */
8262 && require_all_args
8263 && !variadic_args_p
8264 && (!use_default_args
8267 {
8269 {
8271 {
8275 }
8276 else
8283 }
8286 }
8287 /* We can't pass a pack expansion to a non-pack parameter of an alias
8288 template (DR 1430). */
8292 && variadic_args_p
8294 {
8296 {
8298 {
8304 {
8307 "pack expansion argument for non-pack parameter "
8309 else
8311 "pack expansion argument for non-pack parameter "
8315 }
8316 }
8318 found:;
8319 }
8321 }
8323 /* We need to evaluate the template arguments, even though this
8324 template-id may be nested within a "sizeof". */
8333 {
8334 tree arg;
8335 tree parm;
8337 /* Get the Ith template parameter. */
8341 {
8344 }
8346 /* Calculate the next argument. */
8349 else
8354 {
8355 /* Some arguments will be placed in the
8356 template parameter pack PARM. */
8363 {
8364 /* We don't know how many args we have yet, just use the
8365 unconverted (and still packed) ones for now. */
8369 }
8373 /* Store this argument. */
8375 {
8376 lost++;
8377 /* We are done with all of the arguments. */
8379 }
8380 else
8381 {
8384 }
8387 }
8389 {
8391 {
8392 /* "If every valid specialization of a variadic template
8393 requires an empty template parameter pack, the template is
8394 ill-formed, no diagnostic required." So check that the
8395 pattern works with this parameter. */
8400 in_decl);
8402 {
8407 }
8409 /* Recover from missing typename. */
8413 /* We don't know how many args we have yet, just
8414 use the unconverted ones for now. */
8418 }
8419 }
8421 {
8422 /* There must be a default arg in this case. */
8425 /* The position of the first default template argument,
8426 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8427 Record that. */
8431 }
8432 else
8436 {
8439 }
8441 /* This only occurs if there was an error in the template
8442 parameter list itself (which we would already have
8443 reported) that we are trying to recover from, e.g., a class
8444 template with a parameter list such as
8445 template<typename..., typename>. */
8447 else
8453 lost++;
8455 }
8460 {
8462 {
8467 }
8469 }
8479 }
8481 /* Convert all template arguments to their appropriate types, and
8482 return a vector containing the innermost resulting template
8483 arguments. If any error occurs, return error_mark_node. Error and
8484 warning messages are not issued.
8486 Note that no function argument deduction is performed, and default
8487 arguments are used to fill in unspecified arguments. */
8488 tree
8490 {
8492 }
8494 /* Convert all template arguments to their appropriate type, and
8495 instantiate default arguments as needed. This returns a vector
8496 containing the innermost resulting template arguments, or
8497 error_mark_node if unsuccessful. */
8498 tree
8500 tsubst_flags_t complain)
8501 {
8503 }
8505 /* Like coerce_template_parms. If PARMS represents all template
8506 parameters levels, this function returns a vector of vectors
8507 representing all the resulting argument levels. Note that in this
8508 case, only the innermost arguments are coerced because the
8509 outermost ones are supposed to have been coerced already.
8511 Otherwise, if PARMS represents only (the innermost) vector of
8512 parameters, this function returns a vector containing just the
8513 innermost resulting arguments. */
8515 static tree
8517 tree args,
8518 tree in_decl,
8519 tsubst_flags_t complain,
8522 {
8525 tree coerced_args;
8528 {
8530 tree level;
8536 {
8537 tree l;
8541 require_all_args,
8542 use_default_args);
8543 else
8550 }
8551 }
8552 else
8555 require_all_args,
8556 use_default_args);
8558 }
8560 /* Returns 1 if template args OT and NT are equivalent. */
8562 int
8564 {
8573 /* For member templates */
8582 {
8599 }
8603 {
8606 /* Don't treat an alias template specialization with dependent
8607 arguments as equivalent to its underlying type when used as a
8608 template argument; we need them to be distinct so that we
8609 substitute into the specialization arguments at instantiation
8610 time. And aliases can't be equivalent without being ==, so
8611 we don't need to look any deeper.
8613 During partial ordering, however, we need to treat them normally so
8614 that we can order uses of the same alias with different
8615 cv-qualification (79960). */
8619 else
8621 }
8624 else
8625 {
8626 /* Try to treat a template non-type argument that has been converted
8627 to the parameter type as equivalent to one that hasn't yet. */
8640 }
8641 }
8643 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8644 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8645 NEWARG_PTR with the offending arguments if they are non-NULL. */
8647 int
8651 {
8664 {
8669 {
8675 }
8676 }
8678 }
8682 {
8684 }
8686 static void
8688 {
8698 /* We are called both from instantiate_decl, where we've already had a
8699 tinst_level pushed, and instantiate_template, where we haven't.
8700 Compensate. */
8711 else
8720 }
8723 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8724 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8725 documentation for TEMPLATE_ID_EXPR. */
8727 tree
8729 {
8730 tree type;
8738 {
8741 }
8744 {
8746 unknown_type_node,
8748 arglist);
8750 }
8757 }
8759 /* Within the scope of a template class S<T>, the name S gets bound
8760 (in build_self_reference) to a TYPE_DECL for the class, not a
8761 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8762 or one of its enclosing classes, and that type is a template,
8763 return the associated TEMPLATE_DECL. Otherwise, the original
8764 DECL is returned.
8766 Also handle the case when DECL is a TREE_LIST of ambiguous
8767 injected-class-names from different bases. */
8769 tree
8771 {
8775 /* DR 176: A lookup that finds an injected-class-name (10.2
8776 [class.member.lookup]) can result in an ambiguity in certain cases
8777 (for example, if it is found in more than one base class). If all of
8778 the injected-class-names that are found refer to specializations of
8779 the same class template, and if the name is followed by a
8780 template-argument-list, the reference refers to the class template
8781 itself and not a specialization thereof, and is not ambiguous. */
8783 {
8786 {
8792 }
8795 else
8797 }
8803 }
8805 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8806 parameters, find the desired type.
8808 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8810 IN_DECL, if non-NULL, is the template declaration we are trying to
8811 instantiate.
8813 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8814 the class we are looking up.
8816 Issue error and warning messages under control of COMPLAIN.
8818 If the template class is really a local class in a template
8819 function, then the FUNCTION_CONTEXT is the function in which it is
8820 being instantiated.
8822 ??? Note that this function is currently called *twice* for each
8823 template-id: the first time from the parser, while creating the
8824 incomplete type (finish_template_type), and the second type during the
8825 real instantiation (instantiate_template_class). This is surely something
8826 that we want to avoid. It also causes some problems with argument
8827 coercion (see convert_nontype_argument for more information on this). */
8829 static tree
8832 {
8834 tree t;
8837 spec_entry elt;
8838 hashval_t hash;
8841 {
8845 else
8846 {
8853 }
8856 }
8858 {
8861 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8862 an implicit typename for the second A. Deal with it. */
8867 {
8870 }
8871 }
8874 {
8877 }
8879 {
8883 }
8885 {
8888 }
8890 /* Issue an error message if we didn't find a template. */
8892 {
8896 }
8899 /* Make sure it's a user visible template, if it was named by
8900 the user. */
8903 {
8905 {
8909 }
8911 }
8915 /* An alias that just changes the name of a template is equivalent to the
8916 other template, so if any of the arguments are pack expansions, strip
8917 the alias to avoid problems with a pack expansion passed to a non-pack
8918 alias template parameter (DR 1430). */
8923 {
8924 tree parm;
8933 }
8934 else
8935 {
8937 tree gen_tmpl;
8938 tree type_decl;
8946 /* An error occurred while building the template TEMPL, and a
8947 diagnostic has most certainly been emitted for that
8948 already. Let's propagate that error. */
8957 {
8958 /* We've been given an incomplete set of template arguments.
8959 For example, given:
8961 template <class T> struct S1 {
8962 template <class U> struct S2 {};
8963 template <class U> struct S2<U*> {};
8964 };
8966 we will be called with an ARGLIST of `U*', but the
8967 TEMPLATE will be `template <class T> template
8968 <class U> struct S1<T>::S2'. We must fill in the missing
8969 arguments. */
8973 }
8975 /* Now we should have enough arguments. */
8978 /* From here on, we're only interested in the most general
8979 template. */
8981 /* Calculate the BOUND_ARGS. These will be the args that are
8982 actually tsubst'd into the definition to create the
8983 instantiation. */
8985 complain,
8990 /* We were unable to bind the arguments. */
8993 /* In the scope of a template class, explicit references to the
8994 template class refer to the type of the template, not any
8995 instantiation of it. For example, in:
8997 template <class T> class C { void f(C<T>); }
8999 the `C<T>' is just the same as `C'. Outside of the
9000 class, however, such a reference is an instantiation. */
9004 {
9009 }
9011 /* If we already have this specialization, return it. */
9021 /* If the the template's constraints are not satisfied,
9022 then we cannot form a valid type.
9024 Note that the check is deferred until after the hash
9025 lookup. This prevents redundant checks on previously
9026 instantiated specializations. */
9028 {
9030 {
9033 }
9035 }
9039 /* If the deduced arguments are invalid, then the binding
9040 failed. */
9044 complain))
9051 {
9056 }
9066 /* Create the type. */
9068 {
9069 /* The user referred to a specialization of an alias
9070 template represented by GEN_TMPL.
9072 [temp.alias]/2 says:
9074 When a template-id refers to the specialization of an
9075 alias template, it is equivalent to the associated
9076 type obtained by substitution of its
9077 template-arguments for the template-parameters in the
9078 type-id of the alias template. */
9081 /* Note that the call above (by indirectly calling
9082 register_specialization in tsubst_decl) registers the
9083 TYPE_DECL representing the specialization of the alias
9084 template. So next time someone substitutes ARGLIST for
9085 the template parms into the alias template (GEN_TMPL),
9086 she'll get that TYPE_DECL back. */
9090 }
9092 {
9094 {
9105 }
9106 else
9107 {
9108 /* We don't want to call start_enum for this type, since
9109 the values for the enumeration constants may involve
9110 template parameters. And, no one should be interested
9111 in the enumeration constants for such a type. */
9114 }
9118 }
9120 {
9121 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9122 instantiated here. */
9130 /* A local class. Make sure the decl gets registered properly. */
9135 /* This instantiation is another name for the primary
9136 template type. Set the TYPE_CANONICAL field
9137 appropriately. */
9140 /* Some of the template arguments require structural
9141 equality testing, so this template class requires
9142 structural equality testing. */
9144 }
9145 else
9148 /* If we called start_enum or pushtag above, this information
9149 will already be set up. */
9151 {
9158 }
9159 else
9163 {
9169 {
9172 }
9173 }
9177 {
9181 {
9182 tree attributes
9190 }
9191 }
9193 /* Let's consider the explicit specialization of a member
9194 of a class template specialization that is implicitly instantiated,
9195 e.g.:
9196 template<class T>
9197 struct S
9198 {
9199 template<class U> struct M {}; //#0
9200 };
9202 template<>
9203 template<>
9204 struct S<int>::M<char> //#1
9205 {
9206 int i;
9207 };
9208 [temp.expl.spec]/4 says this is valid.
9210 In this case, when we write:
9211 S<int>::M<char> m;
9213 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9214 the one of #0.
9216 When we encounter #1, we want to store the partial instantiation
9217 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9219 For all cases other than this "explicit specialization of member of a
9220 class template", we just want to store the most general template into
9221 the CLASSTYPE_TI_TEMPLATE of M.
9223 This case of "explicit specialization of member of a class template"
9224 only happens when:
9225 1/ the enclosing class is an instantiation of, and therefore not
9226 the same as, the context of the most general template, and
9227 2/ we aren't looking at the partial instantiation itself, i.e.
9228 the innermost arguments are not the same as the innermost parms of
9229 the most general template.
9231 So it's only when 1/ and 2/ happens that we want to use the partial
9232 instantiation of the member template in lieu of its most general
9233 template. */
9237 /* the enclosing class must be an instantiation... */
9240 {
9244 tree partial_inst_args =
9251 use_partial_inst_tmpl =
9252 /*...and we must not be looking at the partial instantiation
9253 itself. */
9255 partial_inst_args);
9256 }
9259 /* This case is easy; there are no member templates involved. */
9261 else
9262 {
9263 /* This is a full instantiation of a member template. Find
9264 the partial instantiation of which this is an instance. */
9266 /* Temporarily reduce by one the number of levels in the ARGLIST
9267 so as to avoid comparing the last set of arguments. */
9271 /* FOUND is either a proper class type, or an alias
9272 template specialization. In the later case, it's a
9273 TYPE_DECL, resulting from the substituting of arguments
9274 for parameters in the TYPE_DECL of the alias template
9275 done earlier. So be careful while getting the template
9276 of FOUND. */
9278 ? found
9282 }
9284 // Build template info for the new specialization.
9293 /* Note this use of the partial instantiation so we can check it
9294 later in maybe_process_partial_specialization. */
9301 /* Now that the type has been registered on the instantiations
9302 list, we set up the enumerators. Because the enumeration
9303 constants may involve the enumeration type itself, we make
9304 sure to register the type first, and then create the
9305 constants. That way, doing tsubst_expr for the enumeration
9306 constants won't result in recursive calls here; we'll find
9307 the instantiation and exit above. */
9311 /* If the type makes use of template parameters, the
9312 code that generates debugging information will crash. */
9315 /* Possibly limit visibility based on template args. */
9322 }
9323 }
9325 /* Wrapper for lookup_template_class_1. */
9327 tree
9330 {
9331 tree ret;
9337 }
9339 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9341 tree
9343 {
9344 /* The type of the expression is NULL_TREE since the template-id could refer
9345 to an explicit or partial specialization. */
9348 /* Except that concepts are always bool. */
9351 }
9353 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9355 tree
9357 {
9361 /* We never want to return a VAR_DECL for a variable concept, since they
9362 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9377 {
9379 {
9382 }
9384 }
9386 /* If a template-id refers to a specialization of a variable
9387 concept, then the expression is true if and only if the
9388 concept's constraints are satisfied by the given template
9389 arguments.
9391 NOTE: This is an extension of Concepts Lite TS that
9392 allows constraints to be used in expressions. */
9394 {
9397 }
9400 }
9402 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9403 TARGS template args, and instantiate it if it's not dependent. */
9405 tree
9407 tsubst_flags_t complain)
9408 {
9411 {
9414 }
9417 }
9419 \f
9420 struct pair_fn_data
9421 {
9422 tree_fn_t fn;
9423 tree_fn_t any_fn;
9425 /* True when we should also visit template parameters that occur in
9426 non-deduced contexts. */
9429 };
9431 /* Called from for_each_template_parm via walk_tree. */
9433 static tree
9435 {
9442 #define WALK_SUBTREE(NODE) \
9443 do \
9444 { \
9445 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9446 pfd->include_nondeduced_p, \
9447 pfd->any_fn); \
9448 if (result) goto out; \
9449 } \
9450 while (0)
9460 {
9464 /* Fall through. */
9470 else
9480 /* Since we're not going to walk subtrees, we have to do this
9481 explicitly here. */
9483 /* Fall through. */
9486 /* Check the return type. */
9489 /* Check the parameter types. Since default arguments are not
9490 instantiated until they are needed, the TYPE_ARG_TYPES may
9491 contain expressions that involve template parameters. But,
9492 no-one should be looking at them yet. And, once they're
9493 instantiated, they don't contain template parameters, so
9494 there's no point in looking at them then, either. */
9495 {
9496 tree parm;
9501 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9502 want walk_tree walking into them itself. */
9504 }
9507 {
9511 }
9528 /* Fall through. */
9540 /* Record template parameters such as `T' inside `TT<T>'. */
9542 /* Fall through. */
9554 /* A template template parameter is encountered. */
9558 /* Already substituted template template parameter */
9563 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9564 partial instantiation. */
9576 /* If there's no type, then this thing must be some expression
9577 involving template parameters. */
9599 }
9601 #undef WALK_SUBTREE
9603 /* We didn't find any template parameters we liked. */
9604 out:
9606 }
9608 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9609 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9610 call FN with the parameter and the DATA.
9611 If FN returns nonzero, the iteration is terminated, and
9612 for_each_template_parm returns 1. Otherwise, the iteration
9613 continues. If FN never returns a nonzero value, the value
9614 returned by for_each_template_parm is 0. If FN is NULL, it is
9615 considered to be the function which always returns 1.
9617 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9618 parameters that occur in non-deduced contexts. When false, only
9619 visits those template parameters that can be deduced. */
9621 static tree
9625 tree_fn_t any_fn)
9626 {
9628 tree result;
9630 /* Set up. */
9636 /* Walk the tree. (Conceptually, we would like to walk without
9637 duplicates, but for_each_template_parm_r recursively calls
9638 for_each_template_parm, so we would need to reorganize a fair
9639 bit to use walk_tree_without_duplicates, so we keep our own
9640 visited list.) */
9643 else
9646 for_each_template_parm_r,
9650 /* Clean up. */
9652 {
9655 }
9658 }
9660 /* Returns true if T depends on any template parameter. */
9662 int
9664 {
9694 else
9695 {
9698 }
9703 }
9705 /* Returns true iff current_function_decl is an incompletely instantiated
9706 template. Useful instead of processing_template_decl because the latter
9707 is set to 0 during instantiate_non_dependent_expr. */
9709 bool
9711 {
9720 }
9722 /* Returns true if T depends on any template parameter with level LEVEL. */
9724 bool
9726 {
9729 }
9731 /* Returns true if the signature of DECL depends on any template parameter from
9732 its enclosing class. */
9734 bool
9736 {
9746 template_parm_outer_level,
9756 }
9758 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9759 ill-formed translation unit, i.e. a variable or function that isn't
9760 usable in a constant expression. */
9764 {
9769 }
9771 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9772 neglectable and instantiated from within an erroneous instantiation. */
9774 static bool
9776 {
9787 }
9795 /* We're starting to instantiate D; record the template instantiation context
9796 for diagnostics and to restore it later. */
9798 bool
9800 {
9802 }
9804 /* We're starting to instantiate D; record the template instantiation context
9805 at LOC for diagnostics and to restore it later. */
9807 bool
9809 {
9813 {
9814 /* Tell error.c not to try to instantiate any templates. */
9817 "template instantiation depth exceeds maximum of %d"
9819 max_tinst_depth);
9821 }
9823 /* If the current instantiation caused problems, don't let it instantiate
9824 anything else. Do allow deduction substitution and decls usable in
9825 constant expressions. */
9829 /* When not -quiet, dump template instantiations other than functions, since
9830 announce_function will take care of those. */
9849 }
9851 /* We're done instantiating this template; return to the instantiation
9852 context. */
9854 void
9856 {
9857 /* Restore the filename and line number stashed away when we started
9858 this instantiation. */
9862 }
9864 /* We're instantiating a deferred template; restore the template
9865 instantiation context in which the instantiation was requested, which
9866 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9868 static tree
9870 {
9882 }
9884 /* Returns the TINST_LEVEL which gives the original instantiation
9885 context. */
9889 {
9895 }
9897 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9898 vector of template arguments, as for tsubst.
9900 Returns an appropriate tsubst'd friend declaration. */
9902 static tree
9904 {
9905 tree new_friend;
9910 /* This was a friend declared with an explicit template
9911 argument list, e.g.:
9913 friend void f<>(T);
9915 to indicate that f was a template instantiation, not a new
9916 function declaration. Now, we have to figure out what
9917 instantiation of what template. */
9918 {
9920 tree new_args;
9921 tree tmpl;
9924 /* Friend functions are looked up in the containing namespace scope.
9925 We must enter that scope, to avoid finding member functions of the
9926 current class with same name. */
9941 tsk_none);
9943 }
9947 /* The NEW_FRIEND will look like an instantiation, to the
9948 compiler, but is not an instantiation from the point of view of
9949 the language. For example, we might have had:
9951 template <class T> struct S {
9952 template <class U> friend void f(T, U);
9953 };
9955 Then, in S<int>, template <class U> void f(int, U) is not an
9956 instantiation of anything. */
9962 {
9966 }
9968 /* The mangled name for the NEW_FRIEND is incorrect. The function
9969 is not a template instantiation and should not be mangled like
9970 one. Therefore, we forget the mangling here; we'll recompute it
9971 later if we need it. */
9973 {
9976 }
9979 {
9980 tree old_decl;
9981 tree new_friend_template_info;
9982 tree new_friend_result_template_info;
9983 tree ns;
9986 /* We must save some information from NEW_FRIEND before calling
9987 duplicate decls since that function will free NEW_FRIEND if
9988 possible. */
9990 new_friend_is_defn =
9995 {
9996 /* This declaration is a `primary' template. */
9999 new_friend_result_template_info
10001 }
10002 else
10005 /* Inside pushdecl_namespace_level, we will push into the
10006 current namespace. However, the friend function should go
10007 into the namespace of the template. */
10017 {
10018 /* This new friend declaration matched an existing
10019 declaration. For example, given:
10021 template <class T> void f(T);
10022 template <class U> class C {
10023 template <class T> friend void f(T) {}
10024 };
10026 the friend declaration actually provides the definition
10027 of `f', once C has been instantiated for some type. So,
10028 old_decl will be the out-of-class template declaration,
10029 while new_friend is the in-class definition.
10031 But, if `f' was called before this point, the
10032 instantiation of `f' will have DECL_TI_ARGS corresponding
10033 to `T' but not to `U', references to which might appear
10034 in the definition of `f'. Previously, the most general
10035 template for an instantiation of `f' was the out-of-class
10036 version; now it is the in-class version. Therefore, we
10037 run through all specialization of `f', adding to their
10038 DECL_TI_ARGS appropriately. In particular, they need a
10039 new set of outer arguments, corresponding to the
10040 arguments for this class instantiation.
10042 The same situation can arise with something like this:
10044 friend void f(int);
10045 template <class T> class C {
10046 friend void f(T) {}
10047 };
10049 when `C<int>' is instantiated. Now, `f(int)' is defined
10050 in the class. */
10053 /* On the other hand, if the in-class declaration does
10054 *not* provide a definition, then we don't want to alter
10055 existing definitions. We can just leave everything
10056 alone. */
10057 ;
10058 else
10059 {
10063 /* Overwrite whatever template info was there before, if
10064 any, with the new template information pertaining to
10065 the declaration. */
10069 {
10070 /* We should have called reregister_specialization in
10071 duplicate_decls. */
10076 /* Instantiate it if the global has already been used. */
10080 }
10081 else
10082 {
10083 tree t;
10085 /* Indicate that the old function template is a partial
10086 instantiation. */
10094 /* Reassign any specializations already in the hash table
10095 to the new more general template, and add the
10096 additional template args. */
10100 {
10102 spec_entry elt;
10114 register_specialization
10117 }
10119 }
10120 }
10122 /* The information from NEW_FRIEND has been merged into OLD_DECL
10123 by duplicate_decls. */
10125 }
10126 }
10127 else
10128 {
10132 /* In the code
10133 template <class T> class C {
10134 template <class U> friend void C1<U>::f (); // case 1
10135 friend void C2<T>::f (); // case 2
10136 };
10137 we only need to make sure CONTEXT is a complete type for
10138 case 2. To distinguish between the two cases, we note that
10139 CONTEXT of case 1 remains dependent type after tsubst while
10140 this isn't true for case 2. */
10150 {
10152 /* do_friend adds the TEMPLATE_DECL for any member friend
10153 template even if it isn't a member template, i.e.
10154 template <class T> friend A<T>::f();
10155 Look through it in that case. */
10159 /* Check to see that the declaration is really present, and,
10160 possibly obtain an improved declaration. */
10165 }
10166 }
10169 }
10171 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10172 template arguments, as for tsubst.
10174 Returns an appropriate tsubst'd friend type or error_mark_node on
10175 failure. */
10177 static tree
10179 {
10180 tree tmpl;
10183 {
10186 }
10191 else
10199 {
10200 /* The friend template has already been declared. Just
10201 check to see that the declarations match, and install any new
10202 default parameters. We must tsubst the default parameters,
10203 of course. We only need the innermost template parameters
10204 because that is all that redeclare_class_template will look
10205 at. */
10208 {
10216 }
10217 }
10218 else
10219 {
10220 /* The friend template has not already been declared. In this
10221 case, the instantiation of the template class will cause the
10222 injection of this template into the namespace scope. */
10226 {
10227 /* The new TMPL is not an instantiation of anything, so we
10228 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10229 for the new type because that is supposed to be the
10230 corresponding template decl, i.e., TMPL. */
10237 /* It is hidden. */
10242 /* Inject this template into the enclosing namspace scope. */
10244 }
10245 }
10249 else
10253 }
10255 /* Returns zero if TYPE cannot be completed later due to circularity.
10256 Otherwise returns one. */
10258 static int
10260 {
10270 else
10272 }
10277 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10278 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10280 static tree
10283 {
10292 {
10299 clauses
10303 else
10305 }
10306 /* If the first attribute argument is an identifier, don't
10307 pass it through tsubst. Attributes like mode, format,
10308 cleanup and several target specific attributes expect it
10309 unmodified. */
10311 {
10312 tree chain
10317 }
10319 {
10320 /* An attribute pack expansion. */
10329 {
10333 }
10335 }
10336 else
10343 }
10345 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10346 unchanged or a new TREE_LIST chain. */
10348 static tree
10351 {
10356 {
10360 }
10364 {
10367 {
10370 {
10376 }
10377 }
10379 }
10382 }
10384 /* Apply any attributes which had to be deferred until instantiation
10385 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10386 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10388 static void
10391 {
10393 tree t;
10400 {
10404 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10405 to our attributes parameter. */
10407 }
10408 else
10409 {
10411 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10412 lookup_template_class_1, and should be preserved. */
10416 }
10420 {
10424 }
10428 {
10433 {
10436 {
10442 }
10443 else
10445 }
10448 }
10449 }
10451 /* Perform (or defer) access check for typedefs that were referenced
10452 from within the template TMPL code.
10453 This is a subroutine of instantiate_decl and instantiate_class_template.
10454 TMPL is the template to consider and TARGS is the list of arguments of
10455 that template. */
10457 static void
10459 {
10460 location_t saved_location;
10471 {
10483 /* Make access check error messages point to the location
10484 of the use of the typedef. */
10488 tf_warning_or_error);
10489 }
10491 }
10493 static tree
10495 {
10497 tree typedecl;
10498 tree pbinfo;
10499 tree base_list;
10501 tree fn_context;
10510 /* Figure out which template is being instantiated. */
10514 /* Mark the type as in the process of being defined. */
10517 /* Determine what specialization of the original template to
10518 instantiate. */
10523 {
10524 /* This TYPE is actually an instantiation of a partial
10525 specialization. We replace the innermost set of ARGS with
10526 the arguments appropriate for substitution. For example,
10527 given:
10529 template <class T> struct S {};
10530 template <class T> struct S<T*> {};
10532 and supposing that we are instantiating S<int*>, ARGS will
10533 presently be {int*} -- but we need {int}. */
10536 }
10537 else
10538 {
10541 }
10543 /* If the template we're instantiating is incomplete, then clearly
10544 there's nothing we can do. */
10546 {
10547 /* We can try again later. */
10550 }
10552 /* If we've recursively instantiated too many templates, stop. */
10556 /* We may be in the middle of deferred access check. Disable
10557 it now. */
10564 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10569 else
10570 {
10573 }
10574 /* Use #pragma pack from the template context. */
10580 /* Set the input location to the most specialized template definition.
10581 This is needed if tsubsting causes an error. */
10593 {
10596 /* Adjust visibility for template arguments. */
10598 }
10604 /* We should never instantiate a nested class before its enclosing
10605 class; we need to look up the nested class by name before we can
10606 instantiate it, and that lookup should instantiate the enclosing
10607 class. */
10613 {
10614 tree pbase_binfo;
10615 tree pushed_scope;
10618 /* We must enter the scope containing the type, as that is where
10619 the accessibility of types named in dependent bases are
10620 looked up from. */
10623 /* Substitute into each of the bases to determine the actual
10624 basetypes. */
10626 {
10627 tree base;
10633 {
10634 expanded_bases =
10641 }
10644 {
10646 /* Extract the already-expanded base class. */
10648 else
10649 /* Substitute to figure out the base class. */
10651 NULL_TREE);
10659 }
10660 }
10662 /* The list is now in reverse order; correct that. */
10667 }
10668 /* Now call xref_basetypes to set up all the base-class
10669 information. */
10677 /* Now that our base classes are set up, enter the scope of the
10678 class, so that name lookups into base classes, etc. will work
10679 correctly. This is precisely analogous to what we do in
10680 begin_class_definition when defining an ordinary non-template
10681 class, except we also need to push the enclosing classes. */
10684 /* Now members are processed in the order of declaration. */
10687 {
10691 {
10693 {
10695 /* A closure type for a lambda in an NSDMI or default argument.
10696 Ignore it; it will be regenerated when needed. */
10699 /* Build new CLASSTYPE_NESTED_UTDS. */
10701 tree newtag;
10707 /* If the member is a class template, then -- even after
10708 substitution -- there may be dependent types in the
10709 template argument list for the class. We increment
10710 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10711 that function will assume that no types are dependent
10712 when outside of a template. */
10722 {
10726 /* Unfortunately, lookup_template_class sets
10727 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10728 instantiation (i.e., for the type of a member
10729 template class nested within a template class.)
10730 This behavior is required for
10731 maybe_process_partial_specialization to work
10732 correctly, but is not accurate in this case;
10733 the TAG is not an instantiation of anything.
10734 (The corresponding TEMPLATE_DECL is an
10735 instantiation, but the TYPE is not.) */
10738 /* Now, we call pushtag to put this NEWTAG into the scope of
10739 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10740 pushtag calling push_template_decl. We don't have to do
10741 this for enums because it will already have been done in
10742 tsubst_enum. */
10746 }
10747 }
10749 {
10750 tree r;
10759 /* Instantiate members marked with attribute used. */
10765 }
10768 /* A closure type for a lambda in an NSDMI or default argument.
10770 else
10771 {
10772 /* Build new TYPE_FIELDS. */
10774 {
10775 tree condition;
10778 condition =
10788 }
10790 {
10791 tree r;
10795 /* The file and line for this declaration, to
10796 assist in error message reporting. Since we
10797 called push_tinst_level above, we don't need to
10798 restore these. */
10808 {
10809 /* A capture pack became multiple fields. */
10812 }
10815 {
10819 {
10820 /* In [temp.inst]:
10822 [t]he initialization (and any associated
10823 side-effects) of a static data member does
10824 not occur unless the static data member is
10825 itself used in a way that requires the
10826 definition of the static data member to
10827 exist.
10829 Therefore, we do not substitute into the
10830 initialized for the static data member here. */
10831 finish_static_data_member_decl
10837 /* Instantiate members marked with attribute used. */
10840 }
10842 {
10843 /* Determine whether R has a valid type and can be
10844 completed later. If R is invalid, then its type
10845 is replaced by error_mark_node. */
10851 {
10852 /* If R's type couldn't be completed and
10853 it isn't a flexible array member (whose
10854 type is incomplete by definition) give
10855 an error. */
10858 }
10859 }
10861 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10862 such a thing will already have been added to the field
10863 list by tsubst_enum in finish_member_declaration in the
10864 CLASSTYPE_NESTED_UTDS case above. */
10868 {
10871 }
10872 }
10873 }
10874 }
10875 }
10876 else
10877 {
10880 {
10881 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10887 {
10888 /* template <class T> friend class C; */
10891 }
10893 {
10894 /* template <class T> friend class C::D; */
10900 }
10903 {
10904 /* This could be either
10906 friend class T::C;
10908 when dependent_type_p is false or
10910 template <class U> friend class T::C;
10912 otherwise. */
10913 /* Bump processing_template_decl in case this is something like
10914 template <class T> friend struct A<T>::B. */
10921 }
10925 {
10926 /* friend class C;
10928 where C hasn't been declared yet. Let's lookup name
10929 from namespace scope directly, bypassing any name that
10930 come from dependent base class. */
10933 /* The call to xref_tag_from_type does injection for friend
10934 classes. */
10936 friend_type =
10940 }
10942 /* friend class C<T>; */
10945 /* Otherwise it's
10947 friend class C;
10949 where C is already declared or
10951 friend class C<int>;
10953 We don't have to do anything in these cases. */
10956 /* Trick make_friend_class into realizing that the friend
10957 we're adding is a template, not an ordinary class. It's
10958 important that we use make_friend_class since it will
10959 perform some error-checking and output cross-reference
10960 information. */
10968 }
10969 else
10970 {
10971 /* Build new DECL_FRIENDLIST. */
10972 tree r;
10974 /* The file and line for this declaration, to
10975 assist in error message reporting. Since we
10976 called push_tinst_level above, we don't need to
10977 restore these. */
10981 {
10984 }
10989 {
10992 }
10993 }
10994 }
10995 }
10998 {
10999 /* Restore these before substituting into the lambda capture
11000 initializers. */
11003 }
11005 /* Set the file and line number information to whatever is given for
11006 the class itself. This puts error messages involving generated
11007 implicit functions at a predictable point, and the same point
11008 that would be used for non-template classes. */
11015 /* We don't instantiate default arguments for member functions. 14.7.1:
11017 The implicit instantiation of a class template specialization causes
11018 the implicit instantiation of the declarations, but not of the
11019 definitions or default arguments, of the class member functions,
11020 member classes, static data members and member templates.... */
11022 /* Some typedefs referenced from within the template code need to be access
11023 checked at template instantiation time, i.e now. These types were
11024 added to the template at parsing time. Let's get those and perform
11025 the access checks then. */
11035 /* The vtable for a template class can be emitted in any translation
11036 unit in which the class is instantiated. When there is no key
11037 method, however, finish_struct_1 will already have added TYPE to
11038 the keyed_classes. */
11043 }
11045 /* Wrapper for instantiate_class_template_1. */
11047 tree
11049 {
11050 tree ret;
11055 }
11057 static tree
11059 {
11060 tree r;
11066 else
11067 {
11074 }
11076 }
11078 /* Given a function parameter pack TMPL_PARM and some function parameters
11079 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11080 and set *SPEC_P to point at the next point in the list. */
11082 tree
11084 {
11085 /* Collect all of the extra "packed" parameters into an
11086 argument pack. */
11087 tree parmvec;
11097 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11101 {
11106 }
11108 /* Build the argument packs. */
11113 }
11115 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11116 NONTYPE_ARGUMENT_PACK. */
11118 static tree
11120 {
11122 }
11124 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11125 pack expansion with no extra args, 2 if it has extra args, or 0
11126 if it is not a pack expansion. */
11128 static int
11130 {
11136 /* A decl pack is itself an expansion. */
11143 }
11146 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11148 static tree
11150 {
11157 }
11159 /* This is a subroutine of tsubst_pack_expansion.
11161 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11162 mechanism to store the (non complete list of) arguments of the
11163 substitution and return a non substituted pack expansion, in order
11164 to wait for when we have enough arguments to really perform the
11165 substitution. */
11167 static bool
11171 {
11172 /* If one pack has an expansion and another pack has a normal
11173 argument or if one pack has an empty argument and an another
11174 one hasn't then tsubst_pack_expansion cannot perform the
11175 substitution and need to fall back on the
11176 PACK_EXPANSION_EXTRA mechanism. */
11184 {
11187 parm_pack;
11189 {
11194 /* We can't substitute a pack expansion with extra args into
11195 our pattern. */
11199 else
11201 }
11205 }
11207 }
11209 /* [temp.variadic]/6 says that:
11211 The instantiation of a pack expansion [...]
11212 produces a list E1,E2, ..., En, where N is the number of elements
11213 in the pack expansion parameters.
11215 This subroutine of tsubst_pack_expansion produces one of these Ei.
11217 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11218 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11219 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11220 INDEX is the index 'i' of the element Ei to produce. ARGS,
11221 COMPLAIN, and IN_DECL are the same parameters as for the
11222 tsubst_pack_expansion function.
11224 The function returns the resulting Ei upon successful completion,
11225 or error_mark_node.
11227 Note that this function possibly modifies the ARGS parameter, so
11228 it's the responsibility of the caller to restore it. */
11230 static tree
11232 tree parm_packs,
11234 tree args /* This parm gets
11236 tsubst_flags_t complain,
11237 tree in_decl)
11238 {
11239 tree t;
11242 /* For each parameter pack, change the substitution of the parameter
11243 pack to the ith argument in its argument pack, then expand the
11244 pattern. */
11246 {
11251 ith_elem_is_expansion |=
11254 /* Select the Ith argument from the pack. */
11258 {
11260 {
11265 }
11266 else
11268 }
11269 else
11270 {
11275 {
11277 /* Update the corresponding argument. */
11279 }
11280 else
11281 /* Re-use the ARGUMENT_PACK_SELECT. */
11283 }
11285 }
11287 /* Substitute into the PATTERN with the (possibly altered)
11288 arguments. */
11290 /* Expanding a fixed parameter pack from
11291 coerce_template_parameter_pack. */
11296 {
11299 else
11302 }
11306 else
11309 /* If the Ith argument pack element is a pack expansion, then
11310 the Ith element resulting from the substituting is going to
11311 be a pack expansion as well. */
11316 }
11318 /* When the unexpanded parameter pack in a fold expression expands to an empty
11319 sequence, the value of the expression is as follows; the program is
11320 ill-formed if the operator is not listed in this table.
11322 && true
11323 || false
11324 , void() */
11326 tree
11328 {
11332 {
11341 }
11347 }
11349 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11350 form an expression that combines the two terms using the
11351 operator of T. */
11353 static tree
11355 {
11359 // Handle compound assignment operators.
11364 {
11374 complain);
11375 }
11376 }
11378 /* Substitute ARGS into the pack of a fold expression T. */
11382 {
11384 }
11386 /* Substitute ARGS into the pack of a fold expression T. */
11390 {
11392 }
11394 /* Expand a PACK of arguments into a grouped as left fold.
11395 Given a pack containing elements A0, A1, ..., An and an
11396 operator @, this builds the expression:
11398 ((A0 @ A1) @ A2) ... @ An
11400 Note that PACK must not be empty.
11402 The operator is defined by the original fold expression T. */
11404 static tree
11406 {
11409 {
11412 }
11414 }
11416 /* Substitute into a unary left fold expression. */
11418 static tree
11420 tree in_decl)
11421 {
11426 {
11430 }
11433 else
11435 }
11437 /* Substitute into a binary left fold expression.
11439 Do ths by building a single (non-empty) vector of argumnts and
11440 building the expression from those elements. */
11442 static tree
11444 tree in_decl)
11445 {
11454 {
11459 }
11467 }
11469 /* Expand a PACK of arguments into a grouped as right fold.
11470 Given a pack containing elementns A0, A1, ..., and an
11471 operator @, this builds the expression:
11473 A0@ ... (An-2 @ (An-1 @ An))
11475 Note that PACK must not be empty.
11477 The operator is defined by the original fold expression T. */
11479 tree
11481 {
11482 // Build the expression.
11486 {
11489 }
11491 }
11493 /* Substitute into a unary right fold expression. */
11495 static tree
11497 tree in_decl)
11498 {
11503 {
11507 }
11510 else
11512 }
11514 /* Substitute into a binary right fold expression.
11516 Do ths by building a single (non-empty) vector of arguments and
11517 building the expression from those elements. */
11519 static tree
11521 tree in_decl)
11522 {
11531 {
11536 }
11545 }
11547 /* Walk through the pattern of a pack expansion, adding everything in
11548 local_specializations to a list. */
11550 struct el_data
11551 {
11552 tree extra;
11553 tsubst_flags_t complain;
11554 };
11555 static tree
11557 {
11562 {
11564 {
11565 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11568 {
11574 }
11576 {
11577 /* Handle lambda capture here, since we aren't doing any
11578 substitution now, and so tsubst_copy won't call
11579 process_outer_var_ref. */
11583 {
11589 {
11590 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11591 proxies. */
11593 {
11598 }
11600 }
11601 }
11602 }
11603 }
11607 }
11609 }
11610 static tree
11612 {
11616 }
11618 /* Substitute ARGS into T, which is an pack expansion
11619 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11620 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11621 (if only a partial substitution could be performed) or
11622 ERROR_MARK_NODE if there was an error. */
11623 tree
11625 tree in_decl)
11626 {
11627 tree pattern;
11632 tree result;
11640 /* Add in any args remembered from an earlier partial instantiation. */
11643 {
11645 {
11646 /* The partial instantiation involved local declarations collected in
11647 extract_local_specs; map from the general template to our local
11648 context. */
11654 /* else inst is already a full instantiation of the pack. */
11656 }
11659 }
11664 /* Determine the argument packs that will instantiate the parameter
11665 packs used in the expansion expression. While we're at it,
11666 compute the number of arguments to be expanded and make sure it
11667 is consistent. */
11670 {
11677 {
11682 else
11685 }
11687 {
11688 /* ??? Support use in other patterns. */
11692 }
11694 {
11695 /* We know we have correct local_specializations if this
11696 expansion is at function scope, or if we're dealing with a
11697 local parameter in a requires expression; for the latter,
11698 tsubst_requires_expr set it up appropriately. */
11701 else
11702 /* We can't rely on local_specializations for a parameter
11703 name used later in a function declaration (such as in a
11704 late-specified return type). Even if it exists, it might
11705 have the wrong value for a recursive call. */
11709 {
11710 /* This parameter pack was used in an unevaluated context. Just
11711 make a dummy decl, since it's only used for its type. */
11714 /* Partial instantiation of the parm_pack, we can't build
11715 up an argument pack yet. */
11717 else
11719 }
11721 /* This argument pack isn't fully instantiated yet. We set this
11722 flag rather than clear arg_pack because we do want to do the
11723 optimization below, and we don't want to substitute directly
11724 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11725 where it isn't expected). */
11727 }
11729 {
11733 }
11734 else
11735 {
11741 }
11748 /* This can only happen if we forget to expand an argument
11749 pack somewhere else. Just return an error, silently. */
11750 {
11754 }
11757 {
11761 /* Don't bother trying to do a partial substitution with
11762 incomplete packs; we'll try again after deduction. */
11770 {
11775 pattern);
11776 else
11778 pattern);
11780 }
11782 /* Keep track of the parameter packs and their corresponding
11783 argument packs. */
11786 }
11787 else
11788 {
11789 /* We can't substitute for this parameter pack. We use a flag as
11790 well as the missing_level counter because function parameter
11791 packs don't have a level. */
11794 }
11795 }
11797 /* If the expansion is just T..., return the matching argument pack, unless
11798 we need to call convert_from_reference on all the elements. This is an
11799 important optimization; see c++/68422. */
11802 {
11805 /* If the argument pack is a single pack expansion, pull it out. */
11810 /* Types need no adjustment, nor does sizeof..., and if we still have
11811 some pack expansion args we won't do anything yet. */
11816 /* Also optimize expression pack expansions if we can tell that the
11817 elements won't have reference type. */
11823 /* Otherwise use the normal path so we get convert_from_reference. */
11824 }
11826 /* We cannot expand this expansion expression, because we don't have
11827 all of the argument packs we need. */
11829 {
11830 /* We got some full packs, but we can't substitute them in until we
11831 have values for all the packs. So remember these until then. */
11840 }
11842 {
11843 /* There were no real arguments, we're just replacing a parameter
11844 pack with another version of itself. Substitute into the
11845 pattern and return a PACK_EXPANSION_*. The caller will need to
11846 deal with that. */
11850 else
11854 }
11859 {
11860 /* We're in a late-specified return type, so create our own local
11861 specializations map; the current map is either NULL or (in the
11862 case of recursive unification) might have bindings that we don't
11863 want to use or alter. */
11866 }
11868 /* For each argument in each argument pack, substitute into the
11869 pattern. */
11873 {
11875 i,
11877 in_decl);
11880 {
11883 }
11884 }
11886 /* Update ARGS to restore the substitution from parameter packs to
11887 their argument packs. */
11889 {
11896 else
11897 {
11905 /* Update the corresponding argument. */
11909 else
11911 }
11912 }
11915 {
11918 }
11920 /* If the dependent pack arguments were such that we end up with only a
11921 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11927 }
11929 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11930 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11931 parameter packs; all parms generated from a function parameter pack will
11932 have the same DECL_PARM_INDEX. */
11934 tree
11936 {
11938 tree patparm;
11941 {
11947 }
11948 else
11949 {
11954 }
11957 }
11959 /* Make an argument pack out of the TREE_VEC VEC. */
11961 static tree
11963 {
11964 tree pack;
11968 else
11969 {
11972 }
11975 }
11977 /* Return an exact copy of template args T that can be modified
11978 independently. */
11980 static tree
11982 {
11990 {
11995 }
12001 }
12003 /* Substitute ARGS into the vector or list of template arguments T. */
12005 static tree
12007 {
12019 {
12021 tree new_arg;
12026 {
12027 /* Substitute into an expansion expression. */
12031 /* Add to the expanded length adjustment the number of
12032 expanded arguments. We subtract one from this
12033 measurement, because the argument pack expression
12034 itself is already counted as 1 in
12035 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12036 the argument pack is empty. */
12038 }
12040 {
12041 /* Substitute into each of the arguments. */
12050 else
12055 }
12056 else
12065 }
12070 /* Make space for the expanded arguments coming from template
12071 argument packs. */
12073 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12074 arguments for a member template.
12075 In that case each TREE_VEC in ORIG_T represents a level of template
12076 arguments, and ORIG_T won't carry any non defaulted argument count.
12077 It will rather be the nested TREE_VECs that will carry one.
12078 In other words, ORIG_T carries a non defaulted argument count only
12079 if it doesn't contain any nested TREE_VEC. */
12081 {
12085 }
12087 {
12091 {
12094 /* Now expand the template argument pack "in place". */
12097 }
12098 else
12099 {
12101 out++;
12102 }
12103 }
12106 }
12108 /* Substitute ARGS into one level PARMS of template parameters. */
12110 static tree
12112 {
12119 {
12127 }
12130 }
12132 /* Return the result of substituting ARGS into the template parameters
12133 given by PARMS. If there are m levels of ARGS and m + n levels of
12134 PARMS, then the result will contain n levels of PARMS. For
12135 example, if PARMS is `template <class T> template <class U>
12136 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12137 result will be `template <int*, double, class V>'. */
12139 static tree
12141 {
12145 /* When substituting into a template, we must set
12146 PROCESSING_TEMPLATE_DECL as the template parameters may be
12147 dependent if they are based on one-another, and the dependency
12148 predicates are short-circuit outside of templates. */
12155 {
12162 }
12167 }
12169 /* Return the result of substituting ARGS into one template parameter
12170 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12171 parameter and which TREE_PURPOSE is the default argument of the
12172 template parameter. */
12174 static tree
12176 {
12197 }
12199 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12200 type T. If T is not an aggregate or enumeration type, it is
12201 handled as if by tsubst. IN_DECL is as for tsubst. If
12202 ENTERING_SCOPE is nonzero, T is the context for a template which
12203 we are presently tsubst'ing. Return the substituted value. */
12205 static tree
12207 tree args,
12208 tsubst_flags_t complain,
12209 tree in_decl,
12211 {
12216 {
12221 /* Fall through. */
12225 {
12226 tree argvec;
12227 tree context;
12228 tree r;
12232 /* In "sizeof(X<I>)" we need to evaluate "I". */
12238 /* First, determine the context for the type we are looking
12239 up. */
12242 {
12245 /* If context is a nested class inside a class template,
12246 it may still need to be instantiated (c++/33959). */
12248 }
12250 /* Then, figure out what arguments are appropriate for the
12251 type we are trying to find. For example, given:
12253 template <class T> struct S;
12254 template <class T, class U> void f(T, U) { S<U> su; }
12256 and supposing that we are instantiating f<int, double>,
12257 then our ARGS will be {int, double}, but, when looking up
12258 S we only want {double}. */
12263 else
12264 {
12268 }
12274 }
12275 else
12276 /* This is not a template type, so there's nothing to do. */
12281 }
12282 }
12286 /* Substitute into the default argument ARG (a default argument for
12287 FN), which has the indicated TYPE. */
12289 tree
12291 tsubst_flags_t complain)
12292 {
12297 /* This can happen in invalid code. */
12312 /* This default argument came from a template. Instantiate the
12313 default argument here, not in tsubst. In the case of
12314 something like:
12316 template <class T>
12317 struct S {
12318 static T t();
12319 void f(T = t());
12320 };
12322 we must be careful to do name lookup in the scope of S<T>,
12323 rather than in the current class. */
12325 /* The "this" pointer is not valid in a default argument. */
12327 {
12332 }
12337 /* The default argument expression may cause implicitly defined
12338 member functions to be synthesized, which will result in garbage
12339 collection. We must treat this situation as if we were within
12340 the body of function so as to avoid collecting live data on the
12341 stack. */
12351 /* Restore the "this" pointer. */
12353 {
12356 }
12363 /* Make sure the default argument is reasonable. */
12369 {
12373 }
12376 }
12378 /* Substitute into all the default arguments for FN. */
12380 static void
12382 {
12383 tree arg;
12384 tree tmpl_args;
12388 /* If this function is not yet instantiated, we certainly don't need
12389 its default arguments. */
12392 /* Don't do this again for clones. */
12398 arg;
12404 complain);
12405 }
12407 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12409 static tree
12411 tree lambda_fntype)
12412 {
12417 /* Nobody should be tsubst'ing into non-template functions. */
12421 {
12422 /* If T is not dependent, just return it. */
12426 /* Calculate the most general template of which R is a
12427 specialization. */
12430 /* We're substituting a lambda function under tsubst_lambda_expr but not
12431 directly from it; find the matching function we're already inside.
12432 But don't do this if T is a generic lambda with a single level of
12433 template parms, as in that case we're doing a normal instantiation. */
12439 /* Calculate the complete set of arguments used to
12440 specialize R. */
12442 (DECL_TEMPLATE_RESULT
12448 /* Check to see if we already have this specialization. */
12450 {
12454 }
12456 /* We can see more levels of arguments than parameters if
12457 there was a specialization of a member template, like
12458 this:
12460 template <class T> struct S { template <class U> void f(); }
12461 template <> template <class U> void S<int>::f(U);
12463 Here, we'll be substituting into the specialization,
12464 because that's where we can find the code we actually
12465 want to generate, but we'll have enough arguments for
12466 the most general template.
12468 We also deal with the peculiar case:
12470 template <class T> struct S {
12471 template <class U> friend void f();
12472 };
12473 template <class U> void f() {}
12474 template S<int>;
12475 template void f<double>();
12477 Here, the ARGS for the instantiation of will be {int,
12478 double}. But, we only need as many ARGS as there are
12479 levels of template parameters in CODE_PATTERN. We are
12480 careful not to get fooled into reducing the ARGS in
12481 situations like:
12483 template <class T> struct S { template <class U> void f(U); }
12484 template <class T> template <> void S<T>::f(int) {}
12486 which we can spot because the pattern will be a
12487 specialization in this case. */
12494 }
12495 else
12496 {
12497 /* This special case arises when we have something like this:
12499 template <class T> struct S {
12500 friend void f<int>(int, double);
12501 };
12503 Here, the DECL_TI_TEMPLATE for the friend declaration
12504 will be an IDENTIFIER_NODE. We are being called from
12505 tsubst_friend_function, and we want only to create a
12506 new decl (R) with appropriate types so that we can call
12507 determine_specialization. */
12510 }
12527 /* If we hit excessive deduction depth, the type is bogus even if
12528 it isn't error_mark_node, so don't build a decl. */
12532 /* We do NOT check for matching decls pushed separately at this
12533 point, as they may not represent instantiations of this
12534 template, and in any case are considered separate under the
12535 discrete model. */
12539 /* Clear out the mangled name and RTL for the instantiation. */
12542 /* Leave DECL_INITIAL set on deleted instantiations. */
12547 /* OpenMP UDRs have the only argument a reference to the declared
12548 type. We want to diagnose if the declared type is a reference,
12549 which is invalid, but as references to references are usually
12550 quietly merged, diagnose it here. */
12552 {
12553 tree argtype
12558 "reference type %qT in "
12562 argtype);
12563 }
12566 /* Type-conversion operator. Reconstruct the name, in
12567 case it's the name of one of the template's parameters. */
12577 {
12581 }
12588 /* If this is an instantiation of a function with internal
12589 linkage, we already know what object file linkage will be
12590 assigned to the instantiation. */
12599 /* We'll re-clone as appropriate in instantiate_template. */
12602 /* If we aren't complaining now, return on error before we register
12603 the specialization so that we'll complain eventually. */
12609 /* When instantiating a constrained member, substitute
12610 into the constraints to create a new constraint. */
12613 {
12616 }
12618 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12619 this in the special friend case mentioned above where
12620 GEN_TMPL is NULL. */
12622 {
12627 tree new_r
12630 /* We instantiated this while substituting into
12631 the type earlier (template/friend54.C). */
12634 /* We're not supposed to instantiate default arguments
12635 until they are called, for a template. But, for a
12636 declaration like:
12638 template <class T> void f ()
12639 { extern void g(int i = T()); }
12641 we should do the substitution when the template is
12642 instantiated. We handle the member function case in
12643 instantiate_class_template since the default arguments
12644 might refer to other members of the class. */
12649 }
12650 else
12653 /* Copy the list of befriending classes. */
12657 {
12661 }
12664 {
12668 /* If this is an instantiation of a member template, clone it.
12669 If it isn't, that'll be handled by
12670 clone_constructors_and_destructors. */
12673 }
12684 /* Possibly limit visibility based on template args. */
12687 {
12691 }
12700 }
12702 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12704 static tree
12706 tree lambda_fntype)
12707 {
12708 /* We can get here when processing a member function template,
12709 member class template, or template template parameter. */
12712 tree spec;
12713 tree tmpl_args;
12714 tree full_args;
12715 tree r;
12719 {
12720 /* Template template parameter is treated here. */
12724 /* If we get a real template back, return it. This can happen in
12725 the context of most_specialized_partial_spec. */
12728 else
12729 /* The new TEMPLATE_DECL was built in
12730 reduce_template_parm_level. */
12733 }
12736 {
12737 /* We might already have an instance of this template.
12738 The ARGS are for the surrounding class type, so the
12739 full args contain the tsubst'd args for the context,
12740 plus the innermost args from the template decl. */
12744 /* Because this is a template, the arguments will still be
12745 dependent, even after substitution. If
12746 PROCESSING_TEMPLATE_DECL is not set, the dependency
12747 predicates will short-circuit. */
12755 /* If this is a default template template argument,
12756 tsubst might not have changed anything. */
12764 }
12766 /* Make a new template decl. It will be similar to the
12767 original, but will record the current template arguments.
12768 We also create a new function declaration, which is just
12769 like the old one, but points to this new template, rather
12770 than the old one. */
12775 // Build new template info linking to the original template decl.
12777 {
12780 }
12781 else
12784 /* The template parameters for this new template are all the
12785 template parameters for the old template, except the
12786 outermost level of parameters. */
12789 complain);
12793 {
12794 tree new_type;
12802 /* For a partial specialization, we need to keep pointing to
12803 the primary template. */
12809 }
12810 else
12811 {
12812 tree new_decl;
12816 else
12826 {
12829 }
12830 else
12831 {
12834 }
12835 }
12845 /* Record this non-type partial instantiation. */
12851 }
12853 /* True if FN is the op() for a lambda in an uninstantiated template. */
12855 bool
12857 {
12862 }
12864 /* We're instantiating a variable from template function TCTX. Return the
12865 corresponding current enclosing scope. This gets complicated because lambda
12866 functions in templates are regenerated rather than instantiated, but generic
12867 lambda functions are subsequently instantiated. */
12869 static tree
12871 {
12880 {
12893 }
12895 }
12897 /* Substitute the ARGS into the T, which is a _DECL. Return the
12898 result of the substitution. Issue error and warning messages under
12899 control of COMPLAIN. */
12901 static tree
12903 {
12904 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12905 location_t saved_loc;
12910 /* Set the filename and linenumber to improve error-reporting. */
12915 {
12925 {
12933 {
12934 /* If there is a local specialization that isn't a
12935 parameter pack, it means that we're doing a "simple"
12936 substitution from inside tsubst_pack_expansion. Just
12937 return the local specialization (which will be a single
12938 parm). */
12945 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12946 the parameters in this function parameter pack. */
12950 {
12953 /* Zero-length parameter packs are boring. Just substitute
12954 into the chain. */
12958 }
12959 else
12960 {
12961 /* All we did was update the type. Make a note of that. */
12964 }
12965 }
12967 /* Loop through all of the parameters we'll build. When T is
12968 a function parameter pack, LEN is the number of expanded
12969 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12972 {
12979 /* We're on the Ith parameter of the function parameter
12980 pack. */
12981 {
12982 /* Get the Ith type. */
12985 /* Rename the parameter to include the index. */
12988 }
12990 /* We're dealing with a normal parameter. */
12998 {
13001 else
13004 }
13014 /* Keep track of the first new parameter we
13015 generate. That's what will be returned to the
13016 caller. */
13020 /* Build a proper chain of parameters when substituting
13021 into a function parameter pack. */
13024 }
13026 /* If cp_unevaluated_operand is set, we're just looking for a
13027 single dummy parameter, so don't keep going. */
13032 /* FIRST_R contains the start of the chain we've built. */
13034 }
13038 {
13045 {
13046 /* This field is a lambda capture pack. Return a TREE_VEC of
13047 the expanded fields to instantiate_class_template_1. */
13051 {
13054 }
13055 else
13056 {
13057 /* All we did was update the type. Make a note of that. */
13060 }
13061 }
13064 {
13067 {
13071 }
13081 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13082 number of bits. */
13088 {
13089 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13090 NSDMI in perform_member_init. Still set DECL_INITIAL
13091 so that we know there is one. */
13096 }
13097 /* We don't have to set DECL_CONTEXT here; it is set by
13098 finish_member_declaration. */
13106 }
13110 }
13114 /* We reach here only for member using decls. We also need to check
13115 uses_template_parms because DECL_DEPENDENT_P is not set for a
13116 using-declaration that designates a member of the current
13117 instantiation (c++/53549). */
13120 {
13124 {
13129 {
13133 {
13136 }
13137 else
13138 {
13141 }
13143 }
13144 }
13145 else
13146 {
13152 else
13153 {
13156 }
13157 }
13158 }
13159 else
13160 {
13163 }
13168 {
13171 tree spec;
13173 tree ctx;
13182 {
13183 /* If this is the canonical decl, we don't have to
13184 mess with instantiations, and often we can't (for
13185 typename, template type parms and such). Note that
13186 TYPE_NAME is not correct for the above test if
13187 we've copied the type for a typedef. */
13193 }
13195 /* Check to see if we already have the specialization we
13196 need. */
13199 {
13200 /* T is a static data member or namespace-scope entity.
13201 We have to substitute into namespace-scope variables
13202 (not just variable templates) because of cases like:
13204 template <class T> void f() { extern T t; }
13206 where the entity referenced is not known until
13207 instantiation time. */
13211 {
13213 complain,
13215 /* If CTX is unchanged, then T is in fact the
13216 specialization we want. That situation occurs when
13217 referencing a static data member within in its own
13218 class. We can use pointer equality, rather than
13219 same_type_p, because DECL_CONTEXT is always
13220 canonical... */
13222 /* ... unless T is a member template; in which
13223 case our caller can be willing to create a
13224 specialization of that template represented
13225 by T. */
13229 }
13232 {
13237 argvec = (coerce_innermost_template_parms
13245 }
13246 }
13247 else
13248 {
13249 /* A local variable. */
13251 /* Subsequent calls to pushdecl will fill this in. */
13253 /* Unless this is a reference to a static variable from an
13254 enclosing function, in which case we need to fill it in now. */
13256 {
13260 }
13262 }
13263 /* If we already have the specialization we need, there is
13264 nothing more to do. */
13266 {
13269 }
13271 /* Create a new node for the specialization we need. */
13274 {
13277 else
13285 {
13286 /* Mask off any template args past the variable's context so we
13287 don't replace the auto with an unrelated argument. */
13291 /* This should never happen with the new lambda instantiation
13292 model, but keep the handling just in case. */
13295 }
13297 }
13299 {
13300 /* Even if the original location is out of scope, the
13301 newly substituted one is not. */
13308 {
13309 /* It may seem that this case cannot occur, since:
13311 typedef void f();
13312 void g() { f x; }
13314 declares a function, not a variable. However:
13316 typedef void f();
13317 template <typename T> void g() { T t; }
13318 template void g<f>();
13320 is an attempt to declare a variable with function
13321 type. */
13323 /* R is not yet sufficiently initialized, so we
13324 just use its name. */
13327 }
13329 /* Wait until cp_finish_decl to set this again, to handle
13330 circular dependency (template/instantiate6.C). */
13335 {
13340 {
13343 }
13345 }
13349 }
13355 /* Clear out the mangled name and RTL for the instantiation. */
13359 /* The initializer must not be expanded until it is required;
13360 see [temp.inst]. */
13364 {
13370 /* Possibly limit visibility based on template args. */
13373 {
13377 }
13379 }
13382 {
13383 /* A static data member declaration is always marked
13384 external when it is declared in-class, even if an
13385 initializer is present. We mimic the non-template
13386 processing here. */
13394 }
13395 else
13396 {
13401 }
13409 /* Preserve a typedef that names a type. */
13411 {
13415 /* An alias template specialization can be dependent
13416 even if its underlying type is not. */
13418 }
13421 }
13426 }
13427 #undef RETURN
13429 out:
13430 /* Restore the file and line information. */
13434 }
13436 /* Substitute into the ARG_TYPES of a function type.
13437 If END is a TREE_CHAIN, leave it and any following types
13438 un-substituted. */
13440 static tree
13442 tree args,
13443 tree end,
13444 tsubst_flags_t complain,
13445 tree in_decl)
13446 {
13447 tree remaining_arg_types;
13451 tree default_arg;
13462 {
13463 /* For a pack expansion, perform substitution on the
13464 entire expression. Later on, we'll handle the arguments
13465 one-by-one. */
13470 /* So that we'll spin through the parameters, one by one. */
13472 else
13473 {
13474 /* We only partially substituted into the parameter
13475 pack. Our type is TYPE_PACK_EXPANSION. */
13478 }
13479 }
13492 {
13494 {
13498 }
13500 }
13501 /* DR 657. */
13505 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13506 top-level qualifiers as required. */
13509 /* We do not substitute into default arguments here. The standard
13510 mandates that they be instantiated only when needed, which is
13511 done in build_over_call. */
13514 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13515 since the new op() won't have any associated template arguments for us
13516 to refer to later. */
13522 {
13523 /* We've instantiated a template before its default arguments
13524 have been parsed. This can happen for a nested template
13525 class, and is not an error unless we require the default
13526 argument in a call of this function. */
13527 remaining_arg_types =
13530 }
13531 else
13532 remaining_arg_types =
13534 }
13537 }
13539 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13540 *not* handle the exception-specification for FNTYPE, because the
13541 initial substitution of explicitly provided template parameters
13542 during argument deduction forbids substitution into the
13543 exception-specification:
13545 [temp.deduct]
13547 All references in the function type of the function template to the
13548 corresponding template parameters are replaced by the specified tem-
13549 plate argument values. If a substitution in a template parameter or
13550 in the function type of the function template results in an invalid
13551 type, type deduction fails. [Note: The equivalent substitution in
13552 exception specifications is done only when the function is instanti-
13553 ated, at which point a program is ill-formed if the substitution
13554 results in an invalid type.] */
13556 static tree
13558 tree args,
13559 tsubst_flags_t complain,
13560 tree in_decl)
13561 {
13562 tree return_type;
13564 tree fntype;
13566 /* The TYPE_CONTEXT is not used for function/method types. */
13569 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13570 failure. */
13574 {
13575 /* Substitute the argument types. */
13587 {
13588 /* DR 1207: 'this' is in scope in the trailing return type. */
13590 }
13592 /* Substitute the return type. */
13596 {
13599 }
13600 }
13601 else
13602 /* Substitute the return type. */
13607 /* DR 486 clarifies that creation of a function type with an
13608 invalid return type is a deduction failure. */
13611 {
13613 {
13616 else
13618 }
13620 }
13621 /* And DR 657. */
13626 {
13627 /* Substitute the argument types. */
13632 }
13634 /* Construct a new type node and return it. */
13636 {
13641 }
13642 else
13643 {
13645 /* Don't pick up extra function qualifiers from the basetype. */
13648 {
13649 /* [temp.deduct]
13651 Type deduction may fail for any of the following
13652 reasons:
13654 -- Attempting to create "pointer to member of T" when T
13655 is not a class type. */
13658 r);
13660 }
13665 }
13672 }
13674 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13675 ARGS into that specification, and return the substituted
13676 specification. If there is no specification, return NULL_TREE. */
13678 static tree
13680 tree args,
13681 tsubst_flags_t complain,
13682 tree in_decl,
13684 {
13685 tree specs;
13686 tree new_specs;
13691 {
13692 /* A noexcept-specifier. */
13697 {
13698 /* Defer instantiation of noexcept-specifiers to avoid
13699 excessive instantiations (c++/49107). */
13702 {
13703 /* We already partially instantiated this member template,
13704 so combine the new args with the old. */
13709 }
13710 else
13711 {
13714 }
13715 }
13716 else
13717 new_specs = tsubst_copy_and_build
13721 }
13723 {
13726 else
13728 {
13729 tree spec;
13734 {
13735 /* Expand the pack expansion type. */
13738 in_decl);
13744 else
13745 {
13746 /* We're substituting into a member template, so
13747 we got a TYPE_PACK_EXPANSION back. Add that
13748 expansion and move on. */
13752 expanded_specs,
13753 complain);
13756 }
13757 }
13760 {
13763 else
13768 complain);
13769 }
13772 }
13773 }
13775 }
13777 /* Take the tree structure T and replace template parameters used
13778 therein with the argument vector ARGS. IN_DECL is an associated
13779 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13780 Issue error and warning messages under control of COMPLAIN. Note
13781 that we must be relatively non-tolerant of extensions here, in
13782 order to preserve conformance; if we allow substitutions that
13783 should not be allowed, we may allow argument deductions that should
13784 not succeed, and therefore report ambiguous overload situations
13785 where there are none. In theory, we could allow the substitution,
13786 but indicate that it should have failed, and allow our caller to
13787 make sure that the right thing happens, but we don't try to do this
13788 yet.
13790 This function is used for dealing with types, decls and the like;
13791 for expressions, use tsubst_expr or tsubst_copy. */
13793 tree
13795 {
13818 else
13823 /* Reuse typedefs. We need to do this to handle dependent attributes,
13824 such as attribute aligned. */
13827 {
13831 {
13832 /* DECL represents an alias template and we want to
13833 instantiate it. */
13837 }
13841 {
13845 }
13850 else
13851 /* The typedef is from a non-template context. */
13855 {
13857 r = cp_build_qualified_type_real
13861 }
13862 else
13863 {
13864 /* We don't have an instantiation yet, so drop the typedef. */
13869 }
13870 }
13887 {
13913 {
13919 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13920 needed. */
13926 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13927 with TREE_SIDE_EFFECTS that indicates this is not an integral
13928 constant expression. */
13931 {
13934 }
13937 }
13943 {
13949 /* Early in template argument deduction substitution, we don't
13950 want to reduce the level of 'auto', or it will be confused
13951 with a normal template parm in subsequent deduction. */
13963 {
13966 /* See through ARGUMENT_PACK_SELECT arguments. */
13969 }
13974 {
13976 /* If ARG is an argument pack, we don't actually want to
13977 perform a substitution here, because substitutions
13978 for argument packs are only done
13979 element-by-element. We can get to this point when
13980 substituting the type of a non-type template
13981 parameter pack, when that type actually contains
13982 template parameter packs from an outer template, e.g.,
13984 template<typename... Types> struct A {
13985 template<Types... Values> struct B { };
13986 }; */
13990 {
13996 return cp_build_qualified_type_real
13998 }
14000 {
14001 /* We are processing a type constructed from a
14002 template template parameter. */
14013 /* Consider this code:
14015 template <template <class> class Template>
14016 struct Internal {
14017 template <class Arg> using Bind = Template<Arg>;
14018 };
14020 template <template <class> class Template, class Arg>
14021 using Instantiate = Template<Arg>; //#0
14023 template <template <class> class Template,
14024 class Argument>
14025 using Bind =
14026 Instantiate<Internal<Template>::template Bind,
14027 Argument>; //#1
14029 When #1 is parsed, the
14030 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14031 parameter `Template' in #0 matches the
14032 UNBOUND_CLASS_TEMPLATE representing the argument
14033 `Internal<Template>::template Bind'; We then want
14034 to assemble the type `Bind<Argument>' that can't
14035 be fully created right now, because
14036 `Internal<Template>' not being complete, the Bind
14037 template cannot be looked up in that context. So
14038 we need to "store" `Bind<Argument>' for later
14039 when the context of Bind becomes complete. Let's
14040 store that in a TYPENAME_TYPE. */
14044 argvec),
14045 typename_type,
14046 complain);
14048 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14049 are resolving nested-types in the signature of a
14050 member function templates. Otherwise ARG is a
14051 TEMPLATE_DECL and is the real template to be
14052 instantiated. */
14060 complain);
14061 return cp_build_qualified_type_real
14063 }
14066 else
14067 /* TEMPLATE_PARM_INDEX. */
14069 }
14072 /* This can happen during the attempted tsubst'ing in
14073 unify. This means that we don't yet have any information
14074 about the template parameter in question. */
14077 /* If we get here, we must have been looking at a parm for a
14078 more deeply nested template. Make a new version of this
14079 template parameter, but with a lower level. */
14081 {
14086 {
14088 r = cp_build_qualified_type_real
14092 }
14099 /* Break infinite recursion when substituting the constraints
14101 else
14102 {
14113 {
14114 /* Propagate constraints on placeholders. */
14119 {
14123 }
14124 }
14127 /* We have reduced the level of the template
14128 template parameter, but not the levels of its
14129 template parameters, so canonical_type_parameter
14130 will not be able to find the canonical template
14131 template parameter for this level. Thus, we
14132 require structural equality checking to compare
14133 TEMPLATE_TEMPLATE_PARMs. */
14137 else
14141 {
14143 /* We might need to substitute into the types of non-type
14144 template parameters. */
14156 }
14157 }
14161 /* OK, now substitute the type of the non-type parameter. We
14162 couldn't do it earlier because it might be an auto parameter,
14163 and we wouldn't need to if we had an argument. */
14172 }
14175 }
14178 {
14186 {
14190 }
14193 {
14197 }
14200 {
14204 }
14210 }
14213 /* We should never be tsubsting a binfo. */
14217 /* A vector of template arguments. */
14223 {
14227 /* [temp.deduct]
14229 Type deduction may fail for any of the following
14230 reasons:
14232 -- Attempting to create a pointer to reference type.
14233 -- Attempting to create a reference to a reference type or
14234 a reference to void.
14236 Core issue 106 says that creating a reference to a reference
14237 during instantiation is no longer a cause for failure. We
14238 only enforce this check in strict C++98 mode. */
14242 {
14245 /* We keep track of the last time we issued this error
14246 message to avoid spewing a ton of messages during a
14247 single bad template instantiation. */
14250 {
14255 else
14258 }
14261 }
14265 {
14267 {
14270 type);
14271 else
14273 type);
14274 }
14276 }
14278 {
14282 }
14284 /* In C++0x, during template argument substitution, when there is an
14285 attempt to create a reference to a reference type, reference
14286 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14288 "If a template-argument for a template-parameter T names a type
14289 that is a reference to a type A, an attempt to create the type
14290 'lvalue reference to cv T' creates the type 'lvalue reference to
14291 A,' while an attempt to create the type type rvalue reference to
14292 cv T' creates the type T"
14293 */
14294 r = cp_build_reference_type
14297 else
14302 /* Will this ever be needed for TYPE_..._TO values? */
14306 }
14308 {
14311 {
14312 /* [temp.deduct]
14314 Type deduction may fail for any of the following
14315 reasons:
14317 -- Attempting to create "pointer to member of T" when T
14318 is not a class type. */
14322 }
14324 {
14328 }
14330 {
14334 }
14337 {
14338 /* The type of the implicit object parameter gets its
14339 cv-qualifiers from the FUNCTION_TYPE. */
14340 tree memptr;
14341 tree method_type
14346 complain);
14347 }
14348 else
14351 complain);
14352 }
14355 {
14356 tree fntype;
14357 tree specs;
14362 /* Substitute the exception specification. */
14370 }
14372 {
14377 /* As an optimization, we avoid regenerating the array type if
14378 it will obviously be the same as T. */
14382 /* These checks should match the ones in create_array_type_for_decl.
14384 [temp.deduct]
14386 The deduction may fail for any of the following reasons:
14388 -- Attempting to create an array with an element type that
14389 is void, a function type, or a reference type, or [DR337]
14390 an abstract class type. */
14396 {
14400 }
14408 {
14411 }
14414 }
14417 {
14429 {
14433 }
14435 {
14436 /* Normally, make_typename_type does not require that the CTX
14437 have complete type in order to allow things like:
14439 template <class T> struct S { typename S<T>::X Y; };
14441 But, such constructs have already been resolved by this
14442 point, so here CTX really should have complete type, unless
14443 it's a partial instantiation. */
14446 {
14450 }
14451 }
14458 {
14461 }
14464 {
14466 {
14470 else
14472 }
14474 {
14478 else
14480 }
14481 }
14483 return cp_build_qualified_type_real
14485 }
14488 {
14500 }
14503 {
14504 tree type;
14520 complain);
14521 }
14524 {
14525 tree type;
14536 {
14538 {
14542 }
14545 }
14556 else
14557 {
14561 /* In a template ~id could be either a complement expression
14562 or an unqualified-id naming a destructor; if instantiating
14563 it produces an expression, it's not an id-expression or
14564 member access. */
14567 }
14572 }
14575 {
14579 }
14583 {
14584 tree r;
14588 else
14596 }
14611 /* We should use one of the expression tsubsts for these codes. */
14617 }
14618 }
14620 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14621 expression on the left-hand side of the "." or "->" operator. We
14622 only do the lookup if we had a dependent BASELINK. Otherwise we
14623 adjust it onto the instantiated heirarchy. */
14625 static tree
14628 {
14640 {
14647 }
14654 {
14660 /* Treat as-if non-dependent below. */
14665 {
14671 }
14675 }
14676 else
14677 /* We're going to overwrite pieces below, make a duplicate. */
14680 /* If lookup found a single function, mark it as used at this point.
14681 (If lookup found multiple functions the one selected later by
14682 overload resolution will be marked as used at that point.) */
14688 {
14689 /* Add back the template arguments, if present. */
14694 /* Update the conversion operator type. */
14696 }
14702 {
14704 qualifying_scope,
14705 object_type);
14707 /* We need to call adjust_result_of_qualified_name_lookup in case the
14708 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14709 so that we still get virtual function binding. */
14711 }
14714 }
14716 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14717 true if the qualified-id will be a postfix-expression in-and-of
14718 itself; false if more of the postfix-expression follows the
14719 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14720 of "&". */
14722 static tree
14726 {
14727 tree expr;
14728 tree scope;
14729 tree name;
14731 tree template_args;
14736 /* Figure out what name to look up. */
14739 {
14749 }
14750 else
14751 {
14754 }
14756 /* Substitute into the qualifying scope. When there are no ARGS, we
14757 are just trying to simplify a non-dependent expression. In that
14758 case the qualifying scope may be dependent, and, in any case,
14759 substituting will not help. */
14762 {
14765 }
14766 else
14770 {
14777 }
14780 {
14782 {
14783 /* A BIT_NOT_EXPR is used to represent a destructor. */
14785 {
14789 }
14790 else
14793 }
14794 else
14798 {
14800 {
14804 }
14806 }
14807 }
14810 {
14812 scope);
14813 /* Remember that there was a reference to this entity. */
14816 }
14819 {
14825 }
14828 {
14831 complain);
14832 else
14834 }
14840 {
14841 expr = (adjust_result_of_qualified_name_lookup
14843 expr = (finish_qualified_id_expr
14847 }
14849 /* Expressions do not generally have reference type. */
14851 /* However, if we're about to form a pointer-to-member, we just
14852 want the referenced member referenced. */
14860 }
14862 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14863 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14864 for tsubst. */
14866 static tree
14869 {
14876 {
14877 /* If we had an initializer but it
14878 instantiated to nothing,
14879 value-initialize the object. This will
14880 only occur when the initializer was a
14881 pack expansion where the parameter packs
14882 used in that expansion were of length
14883 zero. */
14885 complain);
14890 }
14893 }
14895 /* Like tsubst, but deals with expressions. This function just replaces
14896 template parms; to finish processing the resultant expression, use
14897 tsubst_copy_and_build or tsubst_expr. */
14899 static tree
14901 {
14903 tree r;
14911 {
14916 {
14917 /* We get here for a use of 'this' in an NSDMI. */
14921 /* This can happen for a parameter name used later in a function
14922 declaration (such as in a late-specified return type). Just
14923 make a dummy decl, since it's only used for its type. */
14926 /* Give it the template pattern as its context; its true context
14927 hasn't been instantiated yet and this is good enough for
14928 mangling. */
14930 }
14939 {
14940 tree enum_type;
14941 tree v;
14945 /* There is no need to substitute into namespace-scope
14946 enumerators. */
14949 /* If ARGS is NULL, then T is known to be non-dependent. */
14953 /* Unfortunately, we cannot just call lookup_name here.
14954 Consider:
14956 template <int I> int f() {
14957 enum E { a = I };
14958 struct S { void g() { E e = a; } };
14959 };
14961 When we instantiate f<7>::S::g(), say, lookup_name is not
14962 clever enough to find f<7>::a. */
14963 enum_type
14973 /* We didn't find the name. That should never happen; if
14974 name-lookup found it during preliminary parsing, we
14975 should find it again here during instantiation. */
14977 }
14982 {
14983 tree ctx;
14988 {
14991 {
14995 }
14997 }
14998 }
15008 {
15011 {
15012 /* First try name lookup to find the instantiation. */
15015 {
15016 /* Make sure that the one we found is the one we want. */
15020 }
15024 else
15025 {
15026 /* This can happen for a variable used in a
15027 late-specified return type of a local lambda, or for a
15028 local static or constant. Building a new VAR_DECL
15029 should be OK in all those cases. */
15032 /* Avoid infinite recursion (79640). */
15035 {
15036 /* We can't call cp_finish_decl, so handle the
15037 initializer by hand. */
15052 }
15059 }
15060 /* Remember this for subsequent uses. */
15063 }
15066 }
15067 else
15077 /* An OVERLOAD will always be a non-dependent overload set; an
15078 overload set from function scope will just be represented with an
15079 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15081 /* We must have marked any lookups as persistent. */
15097 {
15098 /* Template template argument like the following example need
15099 special treatment:
15101 template <template <class> class TT> struct C {};
15102 template <class T> struct D {
15103 template <class U> struct E {};
15104 C<E> c; // #1
15105 };
15106 D<int> d; // #2
15108 We are processing the template argument `E' in #1 for
15109 the template instantiation #2. Originally, `E' is a
15110 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15111 have to substitute this with one having context `D<int>'. */
15115 {
15116 /* When rewriting a constructor into a deduction guide, a
15117 non-dependent name can become dependent, so memtmpl<args>
15118 becomes context::template memtmpl<args>. */
15122 }
15124 }
15125 else
15126 /* Ordinary template template argument. */
15131 {
15132 /* Handle location wrappers by substituting the wrapped node
15133 first, *then* reusing the resulting type. Doing the type
15134 first ensures that we handle template parameters and
15135 parameter pack expansions. */
15139 }
15149 {
15153 }
15158 {
15167 /* We only want to compute the number of arguments. */
15170 else
15177 {
15179 /* Set TREE_USED for the benefit of -Wunused. */
15183 }
15191 {
15196 else
15202 else
15205 }
15206 else
15208 }
15210 {
15218 }
15219 /* Fall through */
15235 {
15239 }
15242 {
15243 tree object;
15244 tree name;
15249 {
15253 }
15256 {
15266 }
15271 in_decl);
15272 else
15275 }
15313 {
15317 }
15320 {
15325 }
15328 {
15332 }
15335 {
15343 }
15349 {
15356 }
15359 {
15366 }
15369 {
15376 }
15379 {
15380 /* Substituted template arguments */
15389 }
15392 {
15412 }
15437 /* Fall through. */
15440 {
15443 }
15444 else
15448 /* This is handled by tsubst_copy_and_build. */
15452 {
15456 }
15459 /* We shouldn't have built any of these during initial template
15460 generation. Instead, they should be built during instantiation
15461 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15465 {
15475 }
15493 {
15494 /* Instantiate any typedefs in the type. */
15499 }
15502 /* These can sometimes show up in a partial instantiation, but never
15503 involve template parms. */
15519 /* ??? There's no point in copying it for now, but maybe some
15520 day it will contain more information, such as a pointer back
15521 to the containing function, inlined copy or so. */
15525 /* We shouldn't get here, but keep going if !flag_checking. */
15529 }
15530 }
15532 /* Helper function for tsubst_omp_clauses, used for instantiation of
15533 OMP_CLAUSE_DECL of clauses. */
15535 static tree
15537 tree in_decl)
15538 {
15542 /* Handle an OpenMP array section represented as a TREE_LIST (or
15543 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15544 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15545 TREE_LIST. We can handle it exactly the same as an array section
15546 (purpose, value, and a chain), even though the nomenclature
15547 (low_bound, length, etc) is different. */
15549 {
15550 tree low_bound
15556 in_decl);
15565 }
15568 /* Undo convert_from_reference tsubst_expr could have called. */
15574 }
15576 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15578 static tree
15581 {
15586 {
15592 {
15595 {
15601 }
15602 /* FALLTHRU */
15617 in_decl);
15649 {
15652 {
15659 }
15660 else
15662 }
15665 in_decl);
15671 in_decl);
15679 in_decl);
15681 {
15684 }
15689 else
15692 in_decl,
15716 }
15719 {
15729 /* tsubst_expr on SCOPE_REF results in returning
15730 finish_non_static_data_member result. Undo that here. */
15734 {
15739 {
15743 CASE_CONVERT:
15752 /* FALLTHRU */
15756 }
15757 }
15763 {
15766 {
15769 }
15770 }
15774 }
15775 }
15779 {
15784 {
15787 }
15788 }
15790 }
15792 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15794 static tree
15796 tree in_decl)
15797 {
15798 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15818 {
15821 else
15822 {
15826 }
15827 }
15832 #undef RECUR
15833 }
15835 /* Used to temporarily communicate the list of #pragma omp parallel
15836 clauses to #pragma omp for instantiation if they are combined
15837 together. */
15841 /* Substitute one OMP_FOR iterator. */
15843 static void
15848 {
15849 #define RECUR(NODE) \
15850 tsubst_expr ((NODE), args, complain, in_decl, \
15851 integral_constant_expression_p)
15858 {
15861 }
15867 {
15868 /* We need to jump through some hoops to handle declarations in the
15869 init-statement, since we might need to handle auto deduction,
15870 but we need to keep control of initialization. */
15874 }
15875 else
15876 {
15878 {
15881 {
15885 {
15889 CASE_CONVERT:
15897 {
15900 }
15901 /* FALLTHRU */
15905 }
15906 }
15907 }
15908 else
15910 }
15921 {
15923 {
15924 /* Declare the variable, but don't let that initialize it. */
15929 }
15934 {
15939 }
15940 else
15947 }
15950 {
15951 /* Declare and initialize the variable. */
15954 }
15956 {
15960 {
15962 {
15968 {
15971 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15976 }
15979 {
15981 decl);
15983 }
15986 {
15988 decl);
15990 }
15991 else
15993 }
15996 }
15998 {
16003 {
16006 }
16007 }
16008 }
16011 {
16015 }
16016 else
16020 {
16031 {
16039 }
16040 else
16046 {
16052 }
16056 {
16064 }
16065 else
16071 }
16077 #undef RECUR
16078 }
16080 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16081 of OMP_TARGET's body. */
16083 static tree
16085 {
16088 {
16097 }
16099 }
16101 /* Helper function for tsubst_expr. For decomposition declaration
16102 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16103 also the corresponding decls representing the identifiers
16104 of the decomposition declaration. Return DECL if successful
16105 or error_mark_node otherwise, set *FIRST to the first decl
16106 in the list chained through DECL_CHAIN and *CNT to the number
16107 of such decls. */
16109 static tree
16113 {
16118 decl2
16123 {
16125 {
16128 }
16145 {
16148 }
16149 else
16151 }
16154 }
16156 /* Like tsubst_copy for expressions, etc. but also does semantic
16157 processing. */
16159 tree
16162 {
16163 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16164 #define RECUR(NODE) \
16165 tsubst_expr ((NODE), args, complain, in_decl, \
16166 integral_constant_expression_p)
16169 tree r;
16170 location_t loc;
16182 {
16184 {
16185 tree_stmt_iterator i;
16189 }
16204 else
16214 {
16216 tree init;
16222 {
16232 else
16234 }
16237 {
16238 /* We're in tsubst_lambda_expr, we've already inserted a new
16239 capture proxy, so look it up and register it. */
16240 tree inst;
16242 {
16243 inst = (retrieve_local_specialization
16246 }
16247 else
16248 {
16252 }
16255 }
16258 /* Don't copy the old closure; we'll create a new one in
16259 tsubst_lambda_expr. */
16261 else
16262 {
16266 {
16267 /* By marking the declaration as instantiated, we avoid
16268 trying to instantiate it. Since instantiate_decl can't
16269 handle local variables, and since we've already done
16270 all that needs to be done, that's the right thing to
16271 do. */
16276 /* Anonymous aggregates are a special case. */
16279 {
16282 {
16286 }
16288 }
16294 {
16299 }
16300 else
16301 {
16306 {
16307 /* For __PRETTY_FUNCTION__ we have to adjust the
16308 initializer. */
16312 }
16313 else
16317 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16322 {
16324 tree first;
16325 tree ndecl
16333 }
16334 else
16336 }
16337 }
16338 }
16341 }
16351 {
16355 }
16360 {
16361 /* Construct another range_for, if this is not a final
16362 substitution (for inside inside a generic lambda of a
16363 template). Otherwise convert to a regular for. */
16365 stmt = (processing_template_decl
16381 {
16385 }
16386 else
16387 {
16393 }
16399 }
16406 {
16410 }
16416 {
16420 }
16433 else
16434 {
16441 }
16447 {
16456 }
16464 else
16472 else
16493 {
16500 }
16504 {
16506 tree label;
16513 }
16519 /* Computed goto's must be tsubst'd into. On the other hand,
16520 non-computed gotos must not be; the identifier in question
16521 will have no binding. */
16523 else
16529 {
16545 }
16550 {
16555 }
16556 else
16557 {
16562 else
16569 else
16575 else
16577 }
16581 {
16585 {
16587 /* Prevent instantiate_decl from trying to instantiate
16588 this variable. We've already done all that needs to be
16589 done. */
16592 }
16597 }
16603 {
16604 /* Local classes are not independent templates; they are
16605 instantiated along with their containing function. And this
16606 way we don't have to deal with pushing out of one local class
16607 to instantiate a member of another local class. */
16608 /* Closures are handled by the LAMBDA_EXPR. */
16618 }
16622 {
16623 tree condition;
16626 condition =
16628 args,
16637 }
16643 in_decl);
16678 {
16691 in_decl);
16693 {
16700 }
16712 integral_constant_expression_p);
16723 else
16724 {
16732 }
16736 }
16741 /* FALLTHRU */
16748 in_decl);
16765 in_decl);
16776 {
16779 {
16780 /* For combined target teams, ensure the num_teams and
16781 thread_limit clause expressions are evaluated on the host,
16782 before entering the target construct. */
16783 tree c;
16789 {
16798 OMP_CLAUSE_FIRSTPRIVATE);
16802 }
16803 }
16804 }
16864 {
16869 {
16872 }
16878 }
16879 else
16880 {
16887 {
16890 }
16893 {
16898 {
16901 }
16907 }
16908 else
16909 {
16913 }
16916 }
16920 {
16926 {
16930 {
16935 }
16939 }
16940 else
16941 {
16946 }
16947 }
16951 {
16955 }
16968 /* If the first operand was a statement, we're done with it. */
16972 complain));
16986 integral_constant_expression_p));
16987 }
16990 out:
16993 #undef RECUR
16994 #undef RETURN
16995 }
16997 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16998 function. For description of the body see comment above
16999 cp_parser_omp_declare_reduction_exprs. */
17001 static void
17003 {
17009 tree_stmt_iterator tsi;
17020 {
17039 }
17041 {
17061 }
17062 }
17064 /* T is a postfix-expression that is not being used in a function
17065 call. Return the substituted version of T. */
17067 static tree
17069 tsubst_flags_t complain,
17070 tree in_decl)
17071 {
17075 else
17081 }
17083 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17084 instantiation context. Instantiating a pack expansion containing a lambda
17085 might result in multiple lambdas all based on the same lambda in the
17086 template. */
17088 tree
17090 {
17104 else
17112 {
17124 else
17129 {
17138 }
17139 else
17140 {
17146 }
17147 }
17151 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17169 else
17170 {
17171 /* Fix the type of 'this'. */
17177 {
17181 }
17182 else
17183 {
17187 }
17189 /* Let finish_function set this. */
17195 else
17196 /* Still increment function_depth so that we don't GC in the
17197 middle of an expression. */
17213 else
17216 /* The capture list was built up in reverse order; fix that now. */
17223 }
17230 }
17232 /* Like tsubst but deals with expressions and performs semantic
17233 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17235 tree
17237 tree args,
17238 tsubst_flags_t complain,
17239 tree in_decl,
17242 {
17243 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17244 #define RECUR(NODE) \
17245 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17247 integral_constant_expression_p)
17250 location_t loc;
17259 /* N3276 decltype magic only applies to calls at the top level or on the
17260 right side of a comma. */
17265 {
17268 /* Fall through. */
17270 {
17271 tree decl;
17272 cp_id_kind idk;
17277 {
17280 }
17282 /* Look up the name. */
17285 /* By convention, expressions use ERROR_MARK_NODE to indicate
17286 failure, not NULL_TREE. */
17292 integral_constant_expression_p,
17300 input_location);
17304 {
17308 }
17310 }
17313 {
17314 tree object;
17324 {
17329 }
17335 {
17338 }
17339 else
17346 else
17348 }
17351 {
17355 {
17356 /* A type conversion to reference type will be enclosed in
17357 such an indirect ref, but the substitution of the cast
17358 will have also added such an indirect ref. */
17360 }
17361 else
17369 }
17372 {
17376 }
17379 {
17383 {
17388 }
17390 /* We'll pass this to convert_nontype_argument again, we don't need
17391 to actually perform any conversion here. */
17397 flags));
17398 }
17401 {
17407 }
17414 {
17415 tree type;
17421 {
17426 }
17433 {
17451 }
17454 }
17488 else
17490 in_decl);
17525 {
17532 tree r = build_x_binary_op
17534 op0,
17536 ? ERROR_MARK
17538 op1,
17540 ? ERROR_MARK
17548 }
17551 {
17555 }
17571 /* Fall through */
17574 {
17575 tree r;
17581 {
17582 /* When there are no ARGS, we are trying to evaluate a
17583 non-dependent expression from the parser. Trying to do
17584 the substitutions may not work. */
17587 }
17588 else
17589 {
17594 else
17597 /*integral_constant_expression_p=*/
17601 }
17605 else
17609 {
17611 {
17613 {
17617 }
17618 else
17622 }
17624 }
17626 }
17629 {
17639 }
17655 {
17659 tree r = build_x_modify_expr
17662 /* TREE_NO_WARNING must be set if either the expression was
17663 parenthesized or it uses an operator such as >>= rather
17664 than plain assignment. In the former case, it was already
17665 set and must be copied. In the latter case,
17666 build_x_modify_expr sets it and it must not be reset
17667 here. */
17672 }
17677 /* Remember that there was a reference to this entity. */
17684 {
17689 tree ret;
17693 else
17694 {
17698 }
17700 /* If there was an initializer in the original tree, but it
17701 instantiated to an empty list, then we should pass a
17702 non-NULL empty vector to tell build_new that it was an
17703 empty initializer() rather than no initializer. This can
17704 only happen when the initializer is a pack expansion whose
17705 parameter packs are of length zero. */
17708 else
17709 {
17713 else
17714 {
17717 }
17718 }
17724 complain);
17732 }
17735 {
17741 complain));
17742 }
17745 {
17749 integral_constant_expression_p);
17751 op0,
17754 }
17757 {
17758 tree function;
17763 tree ret;
17766 /* Internal function with no arguments. */
17770 /* When we parsed the expression, we determined whether or
17771 not Koenig lookup should be performed. */
17774 {
17777 }
17779 {
17784 }
17786 {
17787 /* Do nothing; calling tsubst_copy_and_build on an identifier
17788 would incorrectly perform unqualified lookup again.
17790 Note that we can also have an IDENTIFIER_NODE if the earlier
17791 unqualified lookup found a member function; in that case
17792 koenig_p will be false and we do want to do the lookup
17793 again to find the instantiated member function.
17795 FIXME but doing that causes c++/15272, so we need to stop
17796 using IDENTIFIER_NODE in that situation. */
17798 }
17799 else
17800 {
17802 {
17808 }
17809 else
17814 /* Avoid error about taking the address of a constructor. */
17818 in_decl,
17820 integral_constant_expression_p);
17824 }
17829 {
17834 else
17835 {
17836 /* Expand the pack expansion and push each entry onto
17837 CALL_ARGS. */
17840 {
17845 {
17850 }
17851 }
17852 else
17853 {
17854 /* A partial substitution. Add one entry. */
17856 }
17857 }
17858 }
17860 /* We do not perform argument-dependent lookup if normal
17861 lookup finds a non-function, in accordance with the
17862 expected resolution of DR 218. */
17865 /* If lookup found a member function, the Koenig lookup is
17866 not appropriate, even if an unqualified-name was used
17867 to denote the function. */
17870 /* Only do this when substitution turns a dependent call
17871 into a non-dependent call. */
17879 {
17881 {
17882 /* For backwards compatibility and good diagnostics, try
17883 the unqualified lookup again if we aren't in SFINAE
17884 context. */
17885 tree unq = (tsubst_copy_and_build
17887 integral_constant_expression_p));
17889 {
17892 }
17895 {
17896 /* In a lambda fn, we have to be careful to not
17897 introduce new this captures. Legacy code can't
17898 be using lambdas anyway, so it's ok to be
17899 stricter. */
17904 "and no declarations were found by "
17905 "argument-dependent lookup at the point "
17912 else
17916 {
17927 {
17929 input_location);
17931 "declarations in dependent base %qT are "
17937 else
17941 }
17942 else
17944 "%qD declared here, later in the "
17947 {
17950 }
17951 }
17954 }
17955 }
17957 {
17962 }
17963 }
17965 /* Remember that there was a reference to this entity. */
17969 {
17972 }
17974 /* Put back tf_decltype for the actual call. */
17979 {
17983 {
17985 "wrong number of arguments to "
17988 }
17989 else
17991 input_location),
17996 /* Unsupported internal function with arguments. */
17998 }
18001 complain);
18003 {
18018 complain);
18019 else
18020 ret = (build_new_method_call
18025 complain));
18026 }
18027 else
18030 koenig_p,
18031 complain);
18036 {
18042 {
18048 {
18051 else
18053 /* The thunk location is not interesting. */
18055 }
18056 }
18057 }
18060 }
18063 {
18069 {
18071 {
18076 }
18077 else
18078 {
18083 }
18085 }
18086 else
18087 {
18090 }
18095 }
18098 {
18103 input_location));
18104 }
18107 {
18115 {
18116 /* We have pack expansions, so expand those and
18117 create a new list out of it. */
18120 tree chain;
18123 /* Expand the argument expressions. */
18131 /* Build the rest of the list. */
18136 /* Determine the number of arguments. */
18138 {
18141 }
18144 else
18145 {
18146 /* Since we only performed a partial substitution into
18147 the argument pack, we only RETURN (a single list
18148 node. */
18155 }
18157 /* Convert the argument vectors into a TREE_LIST */
18160 {
18161 /* Grab the Ith values. */
18162 i--;
18165 value
18169 /* Build the list (backwards). */
18171 }
18174 }
18190 }
18193 {
18194 tree object;
18195 tree object_type;
18196 tree member;
18197 tree r;
18201 /* Remember that there was a reference to this entity. */
18212 else
18218 {
18223 }
18227 {
18229 {
18234 {
18237 }
18239 {
18244 }
18245 }
18246 }
18249 {
18250 /* Lookup the template functions now that we know what the
18251 scope is. */
18259 {
18262 args);
18263 member = (adjust_result_of_qualified_name_lookup
18265 object_type));
18266 }
18267 else
18268 {
18270 input_location);
18272 }
18273 }
18277 {
18279 {
18283 else
18286 }
18288 }
18292 complain);
18296 }
18303 {
18311 tree r;
18316 /* We do not want to process the index of aggregate
18317 initializers as they are identifier nodes which will be
18318 looked up by digest_init. */
18324 {
18326 /* An identifier index is looked up in the type
18327 being initialized, not the current scope. */
18332 {
18333 /* Substitute into the pack expansion. */
18335 in_decl);
18339 ;
18341 /* Just move the argument into place. */
18343 else
18344 {
18345 /* Update the length of the final CONSTRUCTOR
18346 arguments vector, and note that we will need to
18347 copy.*/
18350 }
18351 }
18352 else
18354 }
18357 {
18362 {
18364 {
18369 }
18370 else
18372 }
18373 }
18379 {
18384 }
18388 }
18391 {
18394 {
18397 }
18398 else
18399 {
18402 }
18403 }
18408 /* Fall through */
18411 {
18413 /* ??? We're doing a subset of finish_id_expression here. */
18415 && !processing_template_decl
18416 && !cp_unevaluated_operand
18419 {
18421 /* Replace an evaluated use of the thread_local variable with
18422 a call to its wrapper. */
18424 }
18429 /* If the original type was a reference, we'll be wrapped in
18430 the appropriate INDIRECT_REF. */
18433 }
18436 {
18440 }
18443 {
18444 tree object_ptr
18451 }
18458 {
18469 }
18472 {
18478 integral_constant_expression_p);
18482 /* If the resulting list of expression statement is empty,
18483 fold it further into void_node. */
18488 }
18491 {
18495 }
18498 /* We can get here for a constant initializer of non-dependent type.
18499 FIXME stop folding in cp_parser_initializer_clause. */
18500 {
18502 complain);
18504 }
18508 integral_constant_expression_p));
18514 {
18519 complain));
18520 }
18527 /* We should only see these for location wrapper nodes, or within
18528 instantiate_non_dependent_expr (when args is NULL_TREE). */
18533 /* fallthrough. */
18536 /* Handle Objective-C++ constructs, if appropriate. */
18537 {
18538 tree subst
18543 }
18545 }
18547 #undef RECUR
18548 #undef RETURN
18549 out:
18552 }
18554 /* Verify that the instantiated ARGS are valid. For type arguments,
18555 make sure that the type's linkage is ok. For non-type arguments,
18556 make sure they are constants if they are integral or enumerations.
18557 Emit an error under control of COMPLAIN, and return TRUE on error. */
18559 static bool
18561 {
18565 {
18575 }
18577 {
18578 /* [basic.link]: A name with no linkage (notably, the name
18579 of a class or enumeration declared in a local scope)
18580 shall not be used to declare an entity with linkage.
18581 This implies that names with no linkage cannot be used as
18582 template arguments
18584 DR 757 relaxes this restriction for C++0x. */
18589 {
18590 /* DR 488 makes use of a type with no linkage cause
18591 type deduction to fail. */
18593 {
18596 else
18599 }
18601 }
18602 /* In order to avoid all sorts of complications, we do not
18603 allow variably-modified types as template arguments. */
18605 {
18609 }
18610 }
18611 /* Class template and alias template arguments should be OK. */
18613 ;
18614 /* A non-type argument of integral or enumerated type must be a
18615 constant. */
18620 {
18624 }
18626 }
18628 static bool
18630 {
18635 {
18638 }
18642 }
18644 /* We're out of SFINAE context now, so generate diagnostics for the access
18645 errors we saw earlier when instantiating D from TMPL and ARGS. */
18647 static void
18649 {
18661 }
18663 /* Instantiate the indicated variable, function, or alias template TMPL with
18664 the template arguments in TARG_PTR. */
18666 static tree
18668 {
18670 tree fndecl;
18671 tree gen_tmpl;
18672 tree spec;
18680 /* If this function is a clone, handle it specially. */
18682 {
18683 tree spec;
18684 tree clone;
18686 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18687 DECL_CLONED_FUNCTION. */
18693 /* Look for the clone. */
18697 /* We should always have found the clone by now. */
18700 }
18705 /* Check to see if we already have this specialization. */
18709 /* targ_ptr only has the innermost template args, so add the outer ones
18710 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18711 the case of a non-dependent call within a template definition). */
18712 targ_ptr = (add_outermost_template_args
18714 targ_ptr));
18716 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18717 but it doesn't seem to be on the hot path. */
18726 {
18728 {
18732 }
18734 }
18737 complain))
18740 /* We are building a FUNCTION_DECL, during which the access of its
18741 parameters and return types have to be checked. However this
18742 FUNCTION_DECL which is the desired context for access checking
18743 is not built yet. We solve this chicken-and-egg problem by
18744 deferring all checks until we have the FUNCTION_DECL. */
18747 /* Instantiation of the function happens in the context of the function
18748 template, not the context of the overload resolution we're doing. */
18750 /* If there are dependent arguments, e.g. because we're doing partial
18751 ordering, make sure processing_template_decl stays set. */
18755 {
18759 }
18765 {
18766 /* We need to determine if we're using a partial or explicit
18767 specialization now, because the type of the variable could be
18768 different. */
18774 {
18779 }
18780 }
18782 /* Substitute template parameters to obtain the specialization. */
18790 {
18793 }
18795 /* The DECL_TI_TEMPLATE should always be the immediate parent
18796 template, not the most general template. */
18800 /* Now we know the specialization, compute access previously
18801 deferred. Do no access control for inheriting constructors,
18802 as we already checked access for the inherited constructor. */
18805 {
18810 }
18813 /* If we've just instantiated the main entry point for a function,
18814 instantiate all the alternate entry points as well. We do this
18815 by cloning the instantiation of the main entry point, not by
18816 instantiating the template clones. */
18821 {
18823 {
18824 /* Remember to reinstantiate when we're out of SFINAE so the user
18825 can see the errors. */
18827 }
18829 }
18831 }
18833 /* Wrapper for instantiate_template_1. */
18835 tree
18837 {
18838 tree ret;
18843 }
18845 /* Instantiate the alias template TMPL with ARGS. Also push a template
18846 instantiation level, which instantiate_template doesn't do because
18847 functions and variables have sufficient context established by the
18848 callers. */
18850 static tree
18852 {
18859 {
18862 }
18864 args =
18872 /* We can't free this if a pending_template entry or last_error_tinst_level
18873 is pointing at it. */
18879 }
18881 /* PARM is a template parameter pack for FN. Returns true iff
18882 PARM is used in a deducible way in the argument list of FN. */
18884 static bool
18886 {
18889 {
18891 tree packs;
18897 {
18898 /* The template parameter pack is used in a function parameter
18899 pack. If this is the end of the parameter list, the
18900 template parameter pack is deducible. */
18903 else
18904 /* Otherwise, not. Well, it could be deduced from
18905 a non-pack parameter, but doing so would end up with
18906 a deduction mismatch, so don't bother. */
18908 }
18909 }
18910 /* The template parameter pack isn't used in any function parameter
18911 packs, but it might be used deeper, e.g. tuple<Args...>. */
18913 }
18915 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18916 NARGS elements of the arguments that are being used when calling
18917 it. TARGS is a vector into which the deduced template arguments
18918 are placed.
18920 Returns either a FUNCTION_DECL for the matching specialization of FN or
18921 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18922 true, diagnostics will be printed to explain why it failed.
18924 If FN is a conversion operator, or we are trying to produce a specific
18925 specialization, RETURN_TYPE is the return type desired.
18927 The EXPLICIT_TARGS are explicit template arguments provided via a
18928 template-id.
18930 The parameter STRICT is one of:
18932 DEDUCE_CALL:
18933 We are deducing arguments for a function call, as in
18934 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18935 deducing arguments for a call to the result of a conversion
18936 function template, as in [over.call.object].
18938 DEDUCE_CONV:
18939 We are deducing arguments for a conversion function, as in
18940 [temp.deduct.conv].
18942 DEDUCE_EXACT:
18943 We are deducing arguments when doing an explicit instantiation
18944 as in [temp.explicit], when determining an explicit specialization
18945 as in [temp.expl.spec], or when taking the address of a function
18946 template, as in [temp.deduct.funcaddr]. */
18948 tree
18950 tree explicit_targs,
18951 tree targs,
18954 tree return_type,
18955 unification_kind_t strict,
18959 {
18960 tree parms;
18961 tree fntype;
18974 tree tinst;
18980 full_targs = (add_outermost_template_args
18982 targs));
18987 /* In C++0x, it's possible to have a function template whose type depends
18988 on itself recursively. This is most obvious with decltype, but can also
18989 occur with enumeration scope (c++/48969). So we need to catch infinite
18990 recursion and reject the substitution at deduction time; this function
18991 will return error_mark_node for any repeated substitution.
18993 This also catches excessive recursion such as when f<N> depends on
18994 f<N-1> across all integers, and returns error_mark_node for all the
18995 substitutions back up to the initial one.
18997 This is, of course, not reentrant. */
19007 {
19008 /* [temp.deduct]
19010 The specified template arguments must match the template
19011 parameters in kind (i.e., type, nontype, template), and there
19012 must not be more arguments than there are parameters;
19013 otherwise type deduction fails.
19015 Nontype arguments must match the types of the corresponding
19016 nontype template parameters, or must be convertible to the
19017 types of the corresponding nontype parameters as specified in
19018 _temp.arg.nontype_, otherwise type deduction fails.
19020 All references in the function type of the function template
19021 to the corresponding template parameters are replaced by the
19022 specified template argument values. If a substitution in a
19023 template parameter or in the function type of the function
19024 template results in an invalid type, type deduction fails. */
19035 explicit_targs);
19037 /* Adjust any explicit template arguments before entering the
19038 substitution context. */
19039 explicit_targs
19041 complain,
19047 /* Substitute the explicit args into the function type. This is
19048 necessary so that, for instance, explicitly declared function
19049 arguments can match null pointed constants. If we were given
19050 an incomplete set of explicit args, we must not do semantic
19051 processing during substitution as we could create partial
19052 instantiations. */
19054 {
19059 /* Dig out the actual parm. */
19062 {
19065 }
19067 {
19070 }
19073 /* No explicit argument for this template parameter. */
19077 {
19078 /* Mark the argument pack as "incomplete". We could
19079 still deduce more arguments during unification.
19080 We remove this mark in type_unification_real. */
19082 {
19086 }
19088 /* We have some incomplete argument packs. */
19090 }
19091 }
19095 {
19098 }
19101 /* Ignore any access checks; we'll see them again in
19102 instantiate_template and they might have the wrong
19103 access path at this point. */
19115 /* Place the explicitly specified arguments in TARGS. */
19119 }
19121 /* Never do unification on the 'this' parameter. */
19125 {
19126 /* We're deducing for a call to the result of a template conversion
19127 function. The parms we really want are in return_type. */
19131 }
19133 {
19142 }
19144 /* We allow incomplete unification without an error message here
19145 because the standard doesn't seem to explicitly prohibit it. Our
19146 callers must be ready to deal with unification failures in any
19147 event. */
19150 /* If we aren't explaining yet, push tinst context so we can see where
19151 any errors (e.g. from class instantiations triggered by instantiation
19152 of default template arguments) come from. If we are explaining, this
19153 context is redundant. */
19155 {
19158 }
19160 /* type_unification_real will pass back any access checks from default
19161 template argument substitution. */
19173 /* Now that we have bindings for all of the template arguments,
19174 ensure that the arguments deduced for the template template
19175 parameters have compatible template parameter lists. We cannot
19176 check this property before we have deduced all template
19177 arguments, because the template parameter types of a template
19178 template parameter might depend on prior template parameters
19179 deduced after the template template parameter. The following
19180 ill-formed example illustrates this issue:
19182 template<typename T, template<T> class C> void f(C<5>, T);
19184 template<int N> struct X {};
19186 void g() {
19187 f(X<5>(), 5l); // error: template argument deduction fails
19188 }
19190 The template parameter list of 'C' depends on the template type
19191 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19192 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19193 time that we deduce 'C'. */
19196 {
19199 }
19201 /* All is well so far. Now, check:
19203 [temp.deduct]
19205 When all template arguments have been deduced, all uses of
19206 template parameters in nondeduced contexts are replaced with
19207 the corresponding deduced argument values. If the
19208 substitution results in an invalid type, as described above,
19209 type deduction fails. */
19212 {
19215 }
19217 /* Also collect access checks from the instantiation. */
19230 /* Now perform any access checks encountered during substitution. */
19237 /* If we're looking for an exact match, check that what we got
19238 is indeed an exact match. It might not be if some template
19239 parameters are used in non-deduced contexts. But don't check
19240 for an exact match if we have dependent template arguments;
19241 in that case we're doing partial ordering, and we already know
19242 that we have two candidates that will provide the actual type. */
19244 {
19248 tree sarg
19254 {
19258 }
19259 }
19261 /* After doing deduction with the inherited constructor, actually return an
19262 instantiation of the inheriting constructor. */
19268 fail:
19271 {
19273 /* Reset once we're all the way out. */
19275 }
19277 /* We can't free this if a pending_template entry or last_error_tinst_level
19278 is pointing at it. */
19284 }
19286 /* Adjust types before performing type deduction, as described in
19287 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19288 sections are symmetric. PARM is the type of a function parameter
19289 or the return type of the conversion function. ARG is the type of
19290 the argument passed to the call, or the type of the value
19291 initialized with the result of the conversion function.
19292 ARG_EXPR is the original argument expression, which may be null. */
19294 static int
19298 tree arg_expr)
19299 {
19303 {
19308 /* Swap PARM and ARG throughout the remainder of this
19309 function; the handling is precisely symmetric since PARM
19310 will initialize ARG rather than vice versa. */
19315 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19316 too, but here handle it by stripping the reference from PARM
19317 rather than by adding it to ARG. */
19325 /* Nothing else to do in this case. */
19330 }
19333 {
19334 /* [temp.deduct.call]
19336 If P is not a reference type:
19338 --If A is an array type, the pointer type produced by the
19339 array-to-pointer standard conversion (_conv.array_) is
19340 used in place of A for type deduction; otherwise,
19342 --If A is a function type, the pointer type produced by
19343 the function-to-pointer standard conversion
19344 (_conv.func_) is used in place of A for type deduction;
19345 otherwise,
19347 --If A is a cv-qualified type, the top level
19348 cv-qualifiers of A's type are ignored for type
19349 deduction. */
19354 else
19356 }
19358 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19359 reference to a cv-unqualified template parameter that does not represent a
19360 template parameter of a class template (during class template argument
19361 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19362 an lvalue, the type "lvalue reference to A" is used in place of A for type
19363 deduction. */
19370 /* try_one_overload doesn't provide an arg_expr, but
19371 functions are always lvalues. */
19375 /* [temp.deduct.call]
19377 If P is a cv-qualified type, the top level cv-qualifiers
19378 of P's type are ignored for type deduction. If P is a
19379 reference type, the type referred to by P is used for
19380 type deduction. */
19383 {
19386 }
19388 /* DR 322. For conversion deduction, remove a reference type on parm
19389 too (which has been swapped into ARG). */
19394 }
19396 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19397 template which does contain any deducible template parameters; check if
19398 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19399 unify_one_argument. */
19401 static int
19404 {
19405 tree type;
19409 else
19416 {
19420 }
19422 {
19427 }
19431 else
19433 }
19437 /* Returns true iff the expression EXPR is one from which a template
19438 argument can be deduced. In other words, if it's an undecorated
19439 use of a template non-type parameter. */
19441 static bool
19443 {
19444 /* Strip implicit conversions. */
19448 }
19450 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19451 deducible way; that is, if it has a max value of <PARM> - 1. */
19453 static bool
19455 {
19464 }
19466 /* Returns true iff the template arguments ARGS use a template parameter
19467 in a deducible way. */
19469 static bool
19471 {
19473 {
19478 else
19479 {
19486 else
19488 }
19491 }
19493 }
19495 /* Returns true iff TYPE contains any deducible references to template
19496 parameters, as per 14.8.2.5. */
19498 static bool
19500 {
19504 /* T
19505 cv-list T
19506 TT<T>
19507 TT<i>
19508 TT<> */
19513 /* T*
19514 T&
19515 T&& */
19519 /* T[integer-constant ]
19520 type [i] */
19525 /* T type ::*
19526 type T::*
19527 T T::*
19528 T (type ::*)()
19529 type (T::*)()
19530 type (type ::*)(T)
19531 type (T::*)(T)
19532 T (type ::*)(T)
19533 T (T::*)()
19534 T (T::*)(T) */
19537 || (uses_deducible_template_parms
19540 /* template-name <T> (where template-name refers to a class template)
19541 template-name <i> (where template-name refers to a class template) */
19548 /* type (T)
19549 T()
19550 T(T) */
19553 {
19562 }
19565 }
19567 /* Subroutine of type_unification_real and unify_pack_expansion to
19568 handle unification of a single P/A pair. Parameters are as
19569 for those functions. */
19571 static int
19575 {
19582 /* We can't deduce anything from this, but we might get all the
19583 template args from other function args. */
19586 /* Implicit conversions (Clause 4) will be performed on a function
19587 argument to convert it to the type of the corresponding function
19588 parameter if the parameter type contains no template-parameters that
19589 participate in template argument deduction. */
19592 /* For function parameters with no deducible template parameters,
19593 just return. We'll check non-dependent conversions later. */
19597 {
19599 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19600 | UNIFY_ALLOW_MORE_CV_QUAL
19614 }
19616 /* We only do these transformations if this is the top-level
19617 parameter_type_list in a call or declaration matching; in other
19618 situations (nested function declarators, template argument lists) we
19619 won't be comparing a type to an expression, and we don't do any type
19620 adjustments. */
19622 {
19624 {
19627 {
19628 /* [temp.deduct.type] A template-argument can be
19629 deduced from a pointer to function or pointer
19630 to member function argument if the set of
19631 overloaded functions does not contain function
19632 templates and at most one of a set of
19633 overloaded functions provides a unique
19634 match. */
19638 /* If a unique match was not found, this is a
19639 non-deduced context, so we still succeed. */
19641 }
19647 }
19649 arg_strict |=
19651 }
19652 else
19657 /* For deduction from an init-list we need the actual list. */
19661 }
19663 /* for_each_template_parm callback that always returns 0. */
19665 static int
19667 {
19669 }
19671 /* for_each_template_parm any_fn callback to handle deduction of a template
19672 type argument from the type of an array bound. */
19674 static int
19676 {
19684 {
19690 }
19692 /* Keep walking. */
19694 }
19696 /* Try to deduce any not-yet-deduced template type arguments from the type of
19697 an array bound. This is handled separately from unify because 14.8.2.5 says
19698 "The type of a type parameter is only deduced from an array bound if it is
19699 not otherwise deduced." */
19701 static void
19703 {
19708 }
19710 /* Most parms like fn_type_unification.
19712 If SUBR is 1, we're being called recursively (to unify the
19713 arguments of a function or method parameter of a function
19714 template).
19716 CHECKS is a pointer to a vector of access checks encountered while
19717 substituting default template arguments. */
19719 static int
19721 tree full_targs,
19722 tree xparms,
19726 unification_kind_t strict,
19730 {
19735 tree parms;
19746 /* Reset the number of non-defaulted template arguments contained
19747 in TARGS. */
19750 again:
19758 {
19763 /* For a function parameter pack that occurs at the end of the
19764 parameter-declaration-list, the type A of each remaining
19765 argument of the call is compared with the type P of the
19766 declarator-id of the function parameter pack. */
19772 /* For a function parameter pack that does not occur at the
19773 end of the parameter-declaration-list, the type of the
19774 parameter pack is a non-deduced context. */
19781 explain_p))
19783 }
19788 {
19789 /* Unify the remaining arguments with the pack expansion type. */
19790 tree argvec;
19793 /* Allocate a TREE_VEC and copy in all of the arguments */
19798 /* Copy the parameter into parmvec. */
19804 /* Advance to the end of the list of parameters. */
19806 }
19808 /* Fail if we've reached the end of the parm list, and more args
19809 are present, and the parm list isn't variadic. */
19812 /* Fail if parms are left and they don't have default values and
19813 they aren't all deduced as empty packs (c++/57397). This is
19814 consistent with sufficient_parms_p. */
19817 {
19821 do
19822 {
19825 count++;
19827 }
19831 type_pack_p);
19832 }
19835 {
19836 tsubst_flags_t complain = (explain_p
19837 ? tf_warning_or_error
19842 {
19846 /* Clear the "incomplete" flags on all argument packs now so that
19847 substituting them into later default arguments works. */
19849 {
19852 }
19860 {
19865 }
19867 /* If this is an undeduced nontype parameter that depends on
19868 a type parameter, try another pass; its type may have been
19869 deduced from a later argument than the one from which
19870 this parameter can be deduced. */
19874 {
19877 }
19879 /* Core issue #226 (C++0x) [temp.deduct]:
19881 If a template argument has not been deduced, its
19882 default template argument, if any, is used.
19884 When we are in C++98 mode, TREE_PURPOSE will either
19885 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19886 to explicitly check cxx_dialect here. */
19888 /* OK, there is a default argument. Wait until after the
19889 conversion check to do substitution. */
19892 /* If the type parameter is a parameter pack, then it will
19893 be deduced to an empty parameter pack. */
19895 {
19896 tree arg;
19899 {
19902 }
19903 else
19910 }
19913 }
19915 /* DR 1391: All parameters have args, now check non-dependent parms for
19916 convertibility. */
19920 {
19926 /* For a function parameter pack that occurs at the end of the
19927 parameter-declaration-list, the type A of each remaining
19928 argument of the call is compared with the type P of the
19929 declarator-id of the function parameter pack. */
19935 /* For a function parameter pack that does not occur at the
19936 end of the parameter-declaration-list, the type of the
19937 parameter pack is a non-deduced context. */
19946 explain_p))
19948 }
19950 /* Now substitute into the default template arguments. */
19952 {
19962 {
19963 /* When saw_undeduced == 1, substitution into parm and arg might
19964 fail or not replace all template parameters, and that's
19965 fine. */
19970 }
19983 else
19991 {
19993 /* The position of the first default template argument,
19994 is also the number of non-defaulted arguments in TARGS.
19995 Record that. */
19998 }
19999 }
20003 }
20009 }
20011 /* Subroutine of type_unification_real. Args are like the variables
20012 at the call site. ARG is an overloaded function (or template-id);
20013 we try deducing template args from each of the overloads, and if
20014 only one succeeds, we go with that. Modifies TARGS and returns
20015 true on success. */
20017 static bool
20019 tree targs,
20020 tree parm,
20021 tree arg,
20022 unification_kind_t strict,
20025 {
20032 {
20035 }
20036 else
20040 /* Handle `&x' where `x' is some static or non-static member
20041 function name. */
20047 /* Strip baselink information. */
20052 {
20053 /* If we got some explicit template args, we need to plug them into
20054 the affected templates before we try to unify, in case the
20055 explicit args will completely resolve the templates in question. */
20062 {
20075 {
20080 {
20083 }
20084 }
20087 }
20088 /* If no templates (or more than one) are fully resolved by the
20089 explicit arguments, this template-id is a non-deduced context; it
20090 could still be OK if we deduce all template arguments for the
20091 enclosing call through other arguments. */
20094 }
20097 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20098 -- but the deduction does not succeed because the expression is
20099 not just the function on its own. */
20101 else
20103 {
20108 {
20111 }
20112 }
20114 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20115 to function or pointer to member function argument if the set of
20116 overloaded functions does not contain function templates and at most
20117 one of a set of overloaded functions provides a unique match.
20119 So if we found multiple possibilities, we return success but don't
20120 deduce anything. */
20123 {
20127 {
20132 /* Don't forget explicit template arguments in a pack. */
20136 }
20137 }
20142 }
20144 /* Core DR 115: In contexts where deduction is done and fails, or in
20145 contexts where deduction is not done, if a template argument list is
20146 specified and it, along with any default template arguments, identifies
20147 a single function template specialization, then the template-id is an
20148 lvalue for the function template specialization. */
20150 tree
20152 {
20165 {
20168 }
20170 {
20173 }
20175 {
20178 }
20181 {
20185 /* If we got some explicit template args, we need to plug them into
20186 the affected templates before we try to unify, in case the
20187 explicit args will completely resolve the templates in question. */
20195 {
20208 {
20211 {
20214 }
20216 {
20219 }
20220 }
20221 }
20223 {
20231 {
20232 tree base
20235 }
20239 }
20241 /* There were no good options and at least one bad one, so let the
20242 user know what the problem is. */
20244 }
20246 }
20248 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20249 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20250 different overloads deduce different arguments for a given parm.
20251 ADDR_P is true if the expression for which deduction is being
20252 performed was of the form "& fn" rather than simply "fn".
20254 Returns 1 on success. */
20256 static int
20258 tree orig_targs,
20259 tree targs,
20260 tree parm,
20261 tree arg,
20262 unification_kind_t strict,
20266 {
20268 tree tempargs;
20274 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20275 to function or pointer to member function argument if the set of
20276 overloaded functions does not contain function templates and at most
20277 one of a set of overloaded functions provides a unique match.
20279 So if this is a template, just return success. */
20291 /* We don't copy orig_targs for this because if we have already deduced
20292 some template args from previous args, unify would complain when we
20293 try to deduce a template parameter for the same argument, even though
20294 there isn't really a conflict. */
20301 /* First make sure we didn't deduce anything that conflicts with
20302 explicitly specified args. */
20304 {
20311 /* Since we're unifying against ourselves, we will fill in
20312 template args used in the function parm list with our own
20313 template parms. Discard them. */
20316 {
20317 /* Check that the argument at each index of the deduced argument pack
20318 is equivalent to the corresponding explicitly specified argument.
20319 We may have deduced more arguments than were explicitly specified,
20320 and that's OK. */
20322 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20323 that's wrong if we deduce the same argument pack from multiple
20324 function arguments: it's only incomplete the first time. */
20337 }
20340 }
20343 {
20348 }
20351 }
20353 /* PARM is a template class (perhaps with unbound template
20354 parameters). ARG is a fully instantiated type. If ARG can be
20355 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20356 TARGS are as for unify. */
20358 static tree
20361 {
20362 tree copy_of_targs;
20372 /* We need to make a new template argument vector for the call to
20373 unify. If we used TARGS, we'd clutter it up with the result of
20374 the attempted unification, even if this class didn't work out.
20375 We also don't want to commit ourselves to all the unifications
20376 we've already done, since unification is supposed to be done on
20377 an argument-by-argument basis. In other words, consider the
20378 following pathological case:
20380 template <int I, int J, int K>
20381 struct S {};
20383 template <int I, int J>
20384 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20386 template <int I, int J, int K>
20387 void f(S<I, J, K>, S<I, I, I>);
20389 void g() {
20390 S<0, 0, 0> s0;
20391 S<0, 1, 2> s2;
20393 f(s0, s2);
20394 }
20396 Now, by the time we consider the unification involving `s2', we
20397 already know that we must have `f<0, 0, 0>'. But, even though
20398 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20399 because there are two ways to unify base classes of S<0, 1, 2>
20400 with S<I, I, I>. If we kept the already deduced knowledge, we
20401 would reject the possibility I=1. */
20405 {
20409 }
20411 /* If unification failed, we're done. */
20417 }
20419 /* Given a template type PARM and a class type ARG, find the unique
20420 base type in ARG that is an instance of PARM. We do not examine
20421 ARG itself; only its base-classes. If there is not exactly one
20422 appropriate base class, return NULL_TREE. PARM may be the type of
20423 a partial specialization, as well as a plain template type. Used
20424 by unify. */
20426 static enum template_base_result
20429 {
20431 tree binfo;
20437 {
20438 /* The type could not be completed. */
20441 }
20443 /* Walk in inheritance graph order. The search order is not
20444 important, and this avoids multiple walks of virtual bases. */
20446 {
20451 {
20452 /* If there is more than one satisfactory baseclass, then:
20454 [temp.deduct.call]
20456 If they yield more than one possible deduced A, the type
20457 deduction fails.
20459 applies. */
20461 {
20464 }
20467 }
20468 }
20472 }
20474 /* Returns the level of DECL, which declares a template parameter. */
20476 static int
20478 {
20480 {
20490 }
20492 }
20494 /* Decide whether ARG can be unified with PARM, considering only the
20495 cv-qualifiers of each type, given STRICT as documented for unify.
20496 Returns nonzero iff the unification is OK on that basis. */
20498 static int
20500 {
20506 {
20507 /* Although a CVR qualifier is ignored when being applied to a
20508 substituted template parameter ([8.3.2]/1 for example), that
20509 does not allow us to unify "const T" with "int&" because both
20510 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20511 It is ok when we're allowing additional CV qualifiers
20512 at the outer level [14.8.2.1]/3,1st bullet. */
20522 }
20533 }
20535 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20536 void
20538 {
20542 {
20545 }
20546 else
20547 {
20550 }
20551 }
20553 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20554 do { \
20555 if (unify (TP, TA, P, A, S, EP)) \
20556 return 1; \
20557 } while (0)
20559 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20560 expansion at the end of PACKED_PARMS. Returns 0 if the type
20561 deduction succeeds, 1 otherwise. STRICT is the same as in
20562 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20563 function call argument list. We'll need to adjust the arguments to make them
20564 types. SUBR tells us if this is from a recursive call to
20565 type_unification_real, or for comparing two template argument
20566 lists. */
20568 static int
20572 {
20573 tree parm
20579 /* Add in any args remembered from an earlier partial instantiation. */
20587 /* Determine the parameter packs we will be deducing from the
20588 pattern, and record their current deductions. */
20591 {
20595 /* Determine the index and level of this parameter pack. */
20600 /* Keep track of the parameter packs and their corresponding
20601 argument packs. */
20604 }
20606 /* Loop through all of the arguments that have not yet been
20607 unified and unify each with the pattern. */
20609 {
20610 tree parm;
20614 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20615 or the element of its argument pack at the current index if
20616 this argument was explicitly specified. */
20618 {
20627 {
20630 }
20632 }
20634 /* If we had explicit template arguments, substitute them into the
20635 pattern before deduction. */
20637 {
20638 /* Some arguments might still be unspecified or dependent. */
20646 NULL_TREE);
20651 }
20652 else
20655 /* Unify the pattern with the current argument. */
20657 explain_p))
20660 /* For each parameter pack, collect the deduced value. */
20662 {
20668 }
20669 }
20671 /* Verify that the results of unification with the parameter packs
20672 produce results consistent with what we've seen before, and make
20673 the deduced argument packs available. */
20675 {
20682 /* By default keep the original deduced argument pack.
20683 If necessary, more specific code is going to update the
20684 resulting deduced argument later down in this function. */
20688 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20689 actually deduce anything. */
20697 {
20698 /* If we had fewer function args than explicit template args,
20699 just use the explicits. */
20704 }
20707 {
20708 tree result;
20709 /* Build the deduced *_ARGUMENT_PACK. */
20711 {
20714 }
20715 else
20720 /* Note the deduced argument packs for this parameter
20721 pack. */
20723 }
20727 {
20728 /* We only had the explicitly-provided arguments before, but
20729 now we have a complete set of arguments. */
20735 }
20736 else
20737 {
20743 /* Inconsistent unification of this parameter pack. */
20745 bad_old_arg,
20746 bad_new_arg);
20747 }
20748 }
20751 }
20753 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20754 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20755 parameters and return value are as for unify. */
20757 static int
20761 {
20762 tree parm_max;
20763 tree arg_max;
20767 /* Our representation of array types uses "N - 1" as the
20768 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20769 not an integer constant. We cannot unify arbitrarily
20770 complex expressions, so we eliminate the MINUS_EXPRs
20771 here. */
20775 {
20778 }
20782 {
20783 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20784 trying to unify the type of a variable with the type
20785 of a template parameter. For example:
20787 template <unsigned int N>
20788 void f (char (&) [N]);
20789 int g();
20790 void h(int i) {
20791 char a[g(i)];
20792 f(a);
20793 }
20795 Here, the type of the ARG will be "int [g(i)]", and
20796 may be a SAVE_EXPR, etc. */
20800 }
20802 /* If only one of the bounds used a MINUS_EXPR, compensate
20803 by adding one to the other bound. */
20806 integer_type_node,
20807 parm_max,
20808 integer_one_node);
20811 integer_type_node,
20812 arg_max,
20813 integer_one_node);
20817 }
20819 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20823 static pa_kind_t
20825 {
20834 else
20836 }
20838 /* Deduce the value of template parameters. TPARMS is the (innermost)
20839 set of template parameters to a template. TARGS is the bindings
20840 for those template parameters, as determined thus far; TARGS may
20841 include template arguments for outer levels of template parameters
20842 as well. PARM is a parameter to a template function, or a
20843 subcomponent of that parameter; ARG is the corresponding argument.
20844 This function attempts to match PARM with ARG in a manner
20845 consistent with the existing assignments in TARGS. If more values
20846 are deduced, then TARGS is updated.
20848 Returns 0 if the type deduction succeeds, 1 otherwise. The
20849 parameter STRICT is a bitwise or of the following flags:
20851 UNIFY_ALLOW_NONE:
20852 Require an exact match between PARM and ARG.
20853 UNIFY_ALLOW_MORE_CV_QUAL:
20854 Allow the deduced ARG to be more cv-qualified (by qualification
20855 conversion) than ARG.
20856 UNIFY_ALLOW_LESS_CV_QUAL:
20857 Allow the deduced ARG to be less cv-qualified than ARG.
20858 UNIFY_ALLOW_DERIVED:
20859 Allow the deduced ARG to be a template base class of ARG,
20860 or a pointer to a template base class of the type pointed to by
20861 ARG.
20862 UNIFY_ALLOW_INTEGER:
20863 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20864 case for more information.
20865 UNIFY_ALLOW_OUTER_LEVEL:
20866 This is the outermost level of a deduction. Used to determine validity
20867 of qualification conversions. A valid qualification conversion must
20868 have const qualified pointers leading up to the inner type which
20869 requires additional CV quals, except at the outer level, where const
20870 is not required [conv.qual]. It would be normal to set this flag in
20871 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20872 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20873 This is the outermost level of a deduction, and PARM can be more CV
20874 qualified at this point.
20875 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20876 This is the outermost level of a deduction, and PARM can be less CV
20877 qualified at this point. */
20879 static int
20882 {
20884 tree targ;
20885 tree tparm;
20887 tsubst_flags_t complain = (explain_p
20888 ? tf_warning_or_error
20891 /* I don't think this will do the right thing with respect to types.
20892 But the only case I've seen it in so far has been array bounds, where
20893 signedness is the only information lost, and I think that will be
20894 okay. */
20902 /* We can't deduce anything from this, but we might get all the
20903 template args from other function args. */
20909 /* If PARM uses template parameters, then we can't bail out here,
20910 even if ARG == PARM, since we won't record unifications for the
20911 template parameters. We might need them if we're trying to
20912 figure out which of two things is more specialized. */
20916 /* Handle init lists early, so the rest of the function can assume
20917 we're dealing with a type. */
20919 {
20924 /* Replace T with std::initializer_list<T> for deduction. */
20931 /* We can only deduce from an initializer list argument if the
20932 parameter is std::initializer_list or an array; otherwise this
20933 is a non-deduced context. */
20938 else
20939 {
20941 /* Deduction is defined in terms of a single type, so just punt
20942 on the (bizarre) std::initializer_list<T...>. */
20945 }
20948 {
20955 {
20959 /* It should only be possible to get here for a call. */
20961 elt_strict |= maybe_adjust_types_for_deduction
20964 }
20967 explain_p);
20968 }
20972 {
20973 /* Also deduce from the length of the initializer list. */
20980 }
20982 /* If the std::initializer_list<T> deduction worked, replace the
20983 deduced A with std::initializer_list<A>. */
20985 {
20990 }
20992 }
20994 /* If parm and arg aren't the same kind of thing (template, type, or
20995 expression), fail early. */
20999 /* Immediately reject some pairs that won't unify because of
21000 cv-qualification mismatches. */
21003 /* It is the elements of the array which hold the cv quals of an array
21004 type, and the elements might be template type parms. We'll check
21005 when we recurse. */
21007 /* We check the cv-qualifiers when unifying with template type
21008 parameters below. We want to allow ARG `const T' to unify with
21009 PARM `T' for example, when computing which of two templates
21010 is more specialized, for example. */
21024 {
21028 /* In a type which contains a nested-name-specifier, template
21029 argument values cannot be deduced for template parameters used
21030 within the nested-name-specifier. */
21042 /* The PARM is not one we're trying to unify. Just check
21043 to see if it matches ARG. */
21044 {
21049 else
21051 }
21058 /* Check for mixed types and values. */
21066 {
21069 {
21070 /* First try to match ARG directly. */
21072 explain_p);
21074 {
21075 /* Otherwise, look for a suitable base of ARG, as below. */
21082 }
21083 }
21084 /* ARG must be constructed from a template class or a template
21085 template parameter. */
21090 /* Deduce arguments T, i from TT<T> or TT<i>. */
21096 /* Fall through to deduce template name. */
21097 }
21101 {
21102 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21104 /* Simple cases: Value already set, does match or doesn't. */
21109 }
21110 else
21111 {
21112 /* If PARM is `const T' and ARG is only `int', we don't have
21113 a match unless we are allowing additional qualification.
21114 If ARG is `const int' and PARM is just `T' that's OK;
21115 that binds `const int' to `T'. */
21120 /* Consider the case where ARG is `const volatile int' and
21121 PARM is `const T'. Then, T should be `volatile int'. */
21122 arg = cp_build_qualified_type_real
21127 /* Simple cases: Value already set, does match or doesn't. */
21133 /* Make sure that ARG is not a variable-sized array. (Note
21134 that were talking about variable-sized arrays (like
21135 `int[n]'), rather than arrays of unknown size (like
21136 `int[]').) We'll get very confused by such a type since
21137 the bound of the array is not constant, and therefore
21138 not mangleable. Besides, such types are not allowed in
21139 ISO C++, so we can do as we please here. We do allow
21140 them for 'auto' deduction, since that isn't ABI-exposed. */
21144 /* Strip typedefs as in convert_template_argument. */
21146 }
21148 /* If ARG is a parameter pack or an expansion, we cannot unify
21149 against it unless PARM is also a parameter pack. */
21154 /* If the argument deduction results is a METHOD_TYPE,
21155 then there is a problem.
21156 METHOD_TYPE doesn't map to any real C++ type the result of
21157 the deduction can not be of that type. */
21171 {
21172 /* The PARM is not one we're trying to unify. Just check
21173 to see if it matches ARG. */
21179 }
21185 {
21189 /* We're deducing from an array bound, the type doesn't matter. */
21195 }
21197 /* [temp.deduct.type] If, in the declaration of a function template
21198 with a non-type template-parameter, the non-type
21199 template-parameter is used in an expression in the function
21200 parameter-list and, if the corresponding template-argument is
21201 deduced, the template-argument type shall match the type of the
21202 template-parameter exactly, except that a template-argument
21203 deduced from an array bound may be of any integral type.
21204 The non-type parameter might use already deduced type parameters. */
21209 {
21213 }
21216 /* Template-parameter dependent expression. Just accept it for now.
21217 It will later be processed in convert_template_argument. */
21218 ;
21224 /* Convert the ARG to the type of PARM; the deduced non-type
21225 template argument must exactly match the types of the
21226 corresponding parameter. */
21229 {
21230 /* We haven't deduced the type of this parameter yet. */
21232 /* We deduce from array bounds in try_array_deduction. */
21234 {
21235 /* Deduce it from the non-type argument. */
21240 }
21241 else
21242 /* Try again later. */
21244 }
21245 else
21248 /* If ARG is a parameter pack or an expansion, we cannot unify
21249 against it unless PARM is also a parameter pack. */
21254 {
21257 }
21262 {
21263 /* A pointer-to-member constant can be unified only with
21264 another constant. */
21268 /* Just unify the class member. It would be useless (and possibly
21269 wrong, depending on the strict flags) to unify also
21270 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21271 arg refer to the same variable, even if through different
21272 classes. For instance:
21274 struct A { int x; };
21275 struct B : A { };
21277 Unification of &A::x and &B::x must succeed. */
21280 }
21283 {
21287 /* [temp.deduct.call]
21289 A can be another pointer or pointer to member type that can
21290 be converted to the deduced A via a qualification
21291 conversion (_conv.qual_).
21293 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21294 This will allow for additional cv-qualification of the
21295 pointed-to types if appropriate. */
21298 /* The derived-to-base conversion only persists through one
21299 level of pointers. */
21304 }
21336 /* We have already checked cv-qualification at the top of the
21337 function. */
21341 /* As far as unification is concerned, this wins. Later checks
21342 will invalidate it if necessary. */
21345 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21346 /* Type INTEGER_CST can come from ordinary constant template args. */
21358 {
21368 /* Check for pack expansions in the parameters. */
21370 {
21372 {
21374 /* We can unify against something with a trailing
21375 parameter pack. */
21377 else
21378 /* [temp.deduct.type]/9: If the template argument list of
21379 P contains a pack expansion that is not the last
21380 template argument, the entire template argument list
21381 is a non-deduced context. */
21383 }
21384 }
21386 /* If we don't have enough arguments to satisfy the parameters
21387 (not counting the pack expression at the end), or we have
21388 too many arguments for a parameter list that doesn't end in
21389 a pack expression, we can't unify. */
21395 /* Unify all of the parameters that precede the (optional)
21396 pack expression. */
21398 {
21403 }
21406 DEDUCE_EXACT,
21409 }
21417 {
21425 }
21430 {
21434 {
21435 /* First, we try to unify the PARM and ARG directly. */
21440 {
21441 /* Fallback to the special case allowed in
21442 [temp.deduct.call]:
21444 If P is a class, and P has the form
21445 template-id, then A can be a derived class of
21446 the deduced A. Likewise, if P is a pointer to
21447 a class of the form template-id, A can be a
21448 pointer to a derived class pointed to by the
21449 deduced A. */
21455 {
21456 /* Don't give the derived diagnostic if we're
21457 already dealing with the same template. */
21458 bool same_template
21464 }
21465 }
21466 }
21470 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21471 Then, we should unify `int' and `U'. */
21473 else
21474 /* There's no chance of unification succeeding. */
21479 }
21486 {
21489 tree a;
21495 /* CV qualifications for methods can never be deduced, they must
21496 match exactly. We need to check them explicitly here,
21497 because type_unification_real treats them as any other
21498 cv-qualified parameter. */
21500 && (!check_cv_quals_for_unify
21528 {
21540 }
21543 }
21546 /* Unify a pointer to member with a pointer to member function, which
21547 deduces the type of the member as a function type. */
21549 {
21550 /* Check top-level cv qualifiers */
21558 /* Determine the type of the function we are unifying against. */
21562 }
21581 /* Matched cases are handled by the ARG == PARM test above. */
21585 /* We might get a variable as a non-type template argument in parm if the
21586 corresponding parameter is type-dependent. Make any necessary
21587 adjustments based on whether arg is a reference. */
21591 {
21596 }
21597 /* Now use the normal expression code to check whether they match. */
21608 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21609 or UNDERLYING_TYPE nodes. */
21613 /* Unification fails if we hit an error node. */
21618 {
21628 }
21629 /* FALLTHRU */
21632 /* An unresolved overload is a nondeduced context. */
21636 expr:
21637 /* We must be looking at an expression. This can happen with
21638 something like:
21640 template <int I>
21641 void foo(S<I>, S<I + 2>);
21643 This is a "nondeduced context":
21645 [deduct.type]
21647 The nondeduced contexts are:
21649 --A type that is a template-id in which one or more of
21650 the template-arguments is an expression that references
21651 a template-parameter.
21653 In these cases, we assume deduction succeeded, but don't
21654 actually infer any unifications. */
21659 else
21661 }
21662 }
21663 #undef RECUR_AND_CHECK_FAILURE
21664 \f
21665 /* Note that DECL can be defined in this translation unit, if
21666 required. */
21668 static void
21670 {
21671 tree clone;
21675 }
21677 /* Called if RESULT is explicitly instantiated, or is a member of an
21678 explicitly instantiated class. */
21680 void
21682 {
21685 /* If this entity has already been written out, it's too late to
21686 make any modifications. */
21690 /* For anonymous namespace we don't need to do anything. */
21692 {
21695 }
21698 /* The TREE_PUBLIC flag for function declarations will have been
21699 set correctly by tsubst. */
21702 /* This might have been set by an earlier implicit instantiation. */
21707 else
21708 {
21711 /* Always make artificials weak. */
21714 /* For WIN32 we also want to put explicit instantiations in
21715 linkonce sections. */
21718 }
21720 /* If EXTERN_P, then this function will not be emitted -- unless
21721 followed by an explicit instantiation, at which point its linkage
21722 will be adjusted. If !EXTERN_P, then this function will be
21723 emitted here. In neither circumstance do we want
21724 import_export_decl to adjust the linkage. */
21726 }
21728 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21729 important template arguments. If any are missing, we check whether
21730 they're important by using error_mark_node for substituting into any
21731 args that were used for partial ordering (the ones between ARGS and END)
21732 and seeing if it bubbles up. */
21734 static bool
21736 {
21741 {
21744 }
21746 {
21750 }
21752 }
21754 /* Given two function templates PAT1 and PAT2, return:
21756 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21757 -1 if PAT2 is more specialized than PAT1.
21758 0 if neither is more specialized.
21760 LEN indicates the number of parameters we should consider
21761 (defaulted parameters should not be considered).
21763 The 1998 std underspecified function template partial ordering, and
21764 DR214 addresses the issue. We take pairs of arguments, one from
21765 each of the templates, and deduce them against each other. One of
21766 the templates will be more specialized if all the *other*
21767 template's arguments deduce against its arguments and at least one
21768 of its arguments *does* *not* deduce against the other template's
21769 corresponding argument. Deduction is done as for class templates.
21770 The arguments used in deduction have reference and top level cv
21771 qualifiers removed. Iff both arguments were originally reference
21772 types *and* deduction succeeds in both directions, an lvalue reference
21773 wins against an rvalue reference and otherwise the template
21774 with the more cv-qualified argument wins for that pairing (if
21775 neither is more cv-qualified, they both are equal). Unlike regular
21776 deduction, after all the arguments have been deduced in this way,
21777 we do *not* verify the deduced template argument values can be
21778 substituted into non-deduced contexts.
21780 The logic can be a bit confusing here, because we look at deduce1 and
21781 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21782 can find template arguments for pat1 to make arg1 look like arg2, that
21783 means that arg2 is at least as specialized as arg1. */
21785 int
21787 {
21800 /* Remove the this parameter from non-static member functions. If
21801 one is a non-static member function and the other is not a static
21802 member function, remove the first parameter from that function
21803 also. This situation occurs for operator functions where we
21804 locate both a member function (with this pointer) and non-member
21805 operator (with explicit first operand). */
21807 {
21812 }
21814 {
21817 {
21818 len--;
21820 }
21821 }
21823 /* If only one is a conversion operator, they are unordered. */
21827 /* Consider the return type for a conversion function */
21829 {
21832 len++;
21833 }
21835 processing_template_decl++;
21841 /* Stop when an ellipsis is seen. */
21843 {
21854 {
21855 /* When both arguments are pack expansions, we need only
21856 unify the patterns themselves. */
21860 /* This is the last comparison we need to do. */
21862 }
21864 /* DR 1847: If a particular P contains no template-parameters that
21865 participate in template argument deduction, that P is not used to
21866 determine the ordering. */
21872 {
21876 }
21879 {
21883 }
21889 {
21895 /* Setup the parameter vector, which contains only ARG1. */
21898 /* Setup the argument vector, which contains the remaining
21899 arguments. */
21908 /* We cannot deduce in the other direction, because ARG1 is
21909 a pack expansion but ARG2 is not. */
21911 }
21913 {
21919 /* Setup the parameter vector, which contains only ARG1. */
21922 /* Setup the argument vector, which contains the remaining
21923 arguments. */
21932 /* We cannot deduce in the other direction, because ARG2 is
21933 a pack expansion but ARG1 is not.*/
21935 }
21937 else
21938 {
21939 /* The normal case, where neither argument is a pack
21940 expansion. */
21947 }
21949 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21950 arg2, then arg2 is not as specialized as arg1. */
21956 /* "If, for a given type, deduction succeeds in both directions
21957 (i.e., the types are identical after the transformations above)
21958 and both P and A were reference types (before being replaced with
21959 the type referred to above):
21960 - if the type from the argument template was an lvalue reference and
21961 the type from the parameter template was not, the argument type is
21962 considered to be more specialized than the other; otherwise,
21963 - if the type from the argument template is more cv-qualified
21964 than the type from the parameter template (as described above),
21965 the argument type is considered to be more specialized than the other;
21966 otherwise,
21967 - neither type is more specialized than the other." */
21970 {
21972 {
21975 else
21977 }
21979 {
21984 }
21985 }
21988 /* We've failed to deduce something in either direction.
21989 These must be unordered. */
21992 next:
21996 /* We have already processed all of the arguments in our
21997 handing of the pack expansion type. */
22002 }
22004 /* "In most cases, all template parameters must have values in order for
22005 deduction to succeed, but for partial ordering purposes a template
22006 parameter may remain without a value provided it is not used in the
22007 types being used for partial ordering."
22009 Thus, if we are missing any of the targs1 we need to substitute into
22010 origs1, then pat2 is not as specialized as pat1. This can happen when
22011 there is a nondeduced context. */
22017 processing_template_decl--;
22019 /* If both deductions succeed, the partial ordering selects the more
22020 constrained template. */
22022 {
22027 }
22029 /* All things being equal, if the next argument is a pack expansion
22030 for one function but not for the other, prefer the
22031 non-variadic function. FIXME this is bogus; see c++/41958. */
22035 {
22038 }
22044 else
22046 }
22048 /* Determine which of two partial specializations of TMPL is more
22049 specialized.
22051 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22052 to the first partial specialization. The TREE_PURPOSE is the
22053 innermost set of template parameters for the partial
22054 specialization. PAT2 is similar, but for the second template.
22056 Return 1 if the first partial specialization is more specialized;
22057 -1 if the second is more specialized; 0 if neither is more
22058 specialized.
22060 See [temp.class.order] for information about determining which of
22061 two templates is more specialized. */
22063 static int
22065 {
22066 tree targs;
22075 /* Just like what happens for functions, if we are ordering between
22076 different template specializations, we may encounter dependent
22077 types in the arguments, and we need our dependency check functions
22078 to behave correctly. */
22082 {
22085 }
22089 {
22092 }
22095 /* If both deductions succeed, the partial ordering selects the more
22096 constrained template. */
22100 /* In the case of a tie where at least one of the templates
22101 has a parameter pack at the end, the template with the most
22102 non-packed parameters wins. */
22104 && any_deductions
22107 {
22113 /* We don't count the pack expansion at the end. */
22123 }
22126 }
22128 /* Return the template arguments that will produce the function signature
22129 DECL from the function template FN, with the explicit template
22130 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22131 also match. Return NULL_TREE if no satisfactory arguments could be
22132 found. */
22134 static tree
22136 {
22140 tree decl_arg_types;
22143 tree arg;
22147 /* Never do unification on the 'this' parameter. */
22168 }
22170 /* Return the innermost template arguments that, when applied to a partial
22171 specialization SPEC_TMPL of TMPL, yield the ARGS.
22173 For example, suppose we have:
22175 template <class T, class U> struct S {};
22176 template <class T> struct S<T*, int> {};
22178 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22179 partial specialization and the ARGS will be {double*, int}. The resulting
22180 vector will be {double}, indicating that `T' is bound to `double'. */
22182 static tree
22184 {
22186 tree spec_args
22189 tree deduced_args;
22190 tree innermost_deduced_args;
22194 {
22198 innermost_deduced_args);
22199 }
22200 else
22204 again:
22213 {
22215 {
22221 }
22223 }
22227 {
22230 }
22232 /* Verify that nondeduced template arguments agree with the type
22233 obtained from argument deduction.
22235 For example:
22237 struct A { typedef int X; };
22238 template <class T, class U> struct C {};
22239 template <class T> struct C<T, typename T::X> {};
22241 Then with the instantiation `C<A, int>', we can deduce that
22242 `T' is `A' but unify () does not check whether `typename T::X'
22243 is `int'. */
22254 /* We only need to check the innermost arguments; the other
22255 arguments will always agree. */
22260 /* Now that we have bindings for all of the template arguments,
22261 ensure that the arguments deduced for the template template
22262 parameters have compatible template parameter lists. See the use
22263 of template_template_parm_bindings_ok_p in fn_type_unification
22264 for more information. */
22269 }
22271 // Compare two function templates T1 and T2 by deducing bindings
22272 // from one against the other. If both deductions succeed, compare
22273 // constraints to see which is more constrained.
22274 static int
22276 {
22281 {
22284 }
22287 {
22290 }
22292 // If both deductions succeed, then one may be more constrained.
22297 }
22299 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22300 Return the TREE_LIST node with the most specialized template, if
22301 any. If there is no most specialized template, the error_mark_node
22302 is returned.
22304 Note that this function does not look at, or modify, the
22305 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22306 returned is one of the elements of INSTANTIATIONS, callers may
22307 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22308 and retrieve it from the value returned. */
22310 tree
22312 {
22319 {
22325 {
22326 /* Equally specialized, move to next function. If there
22327 is no next function, nothing's most specialized. */
22332 }
22333 }
22336 /* Now verify that champ is better than everything earlier in the
22337 instantiation list. */
22340 {
22343 }
22344 }
22346 processing_template_decl--;
22352 }
22354 /* If DECL is a specialization of some template, return the most
22355 general such template. Otherwise, returns NULL_TREE.
22357 For example, given:
22359 template <class T> struct S { template <class U> void f(U); };
22361 if TMPL is `template <class U> void S<int>::f(U)' this will return
22362 the full template. This function will not trace past partial
22363 specializations, however. For example, given in addition:
22365 template <class T> struct S<T*> { template <class U> void f(U); };
22367 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22368 `template <class T> template <class U> S<T*>::f(U)'. */
22370 tree
22372 {
22374 {
22377 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22378 template friend, or a FIELD_DECL for a capture pack. */
22381 }
22383 /* Look for more and more general templates. */
22385 {
22386 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22387 (See cp-tree.h for details.) */
22396 /* Stop if we run into an explicitly specialized class template. */
22403 }
22406 }
22408 /* Return the most specialized of the template partial specializations
22409 which can produce TARGET, a specialization of some class or variable
22410 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22411 a TEMPLATE_DECL node corresponding to the partial specialization, while
22412 the TREE_PURPOSE is the set of template arguments that must be
22413 substituted into the template pattern in order to generate TARGET.
22415 If the choice of partial specialization is ambiguous, a diagnostic
22416 is issued, and the error_mark_node is returned. If there are no
22417 partial specializations matching TARGET, then NULL_TREE is
22418 returned, indicating that the primary template should be used. */
22420 static tree
22422 {
22424 tree t;
22425 tree champ;
22432 {
22436 }
22438 {
22441 }
22443 {
22447 }
22448 else
22453 /* For determining which partial specialization to use, only the
22454 innermost args are interesting. */
22456 {
22459 }
22462 {
22463 tree spec_args;
22467 {
22468 /* Substitute in the template args from the enclosing class. */
22472 }
22479 {
22483 /* Keep the candidate only if the constraints are satisfied,
22484 or if we're not compiling with concepts. */
22487 {
22490 }
22491 }
22492 }
22502 {
22505 ;
22506 else
22507 {
22509 {
22512 {
22515 }
22516 }
22518 }
22519 }
22523 {
22526 {
22529 }
22530 }
22533 {
22540 else
22544 {
22549 }
22552 }
22555 }
22557 /* Explicitly instantiate DECL. */
22559 void
22561 {
22566 /* An error occurred, for which grokdeclarator has already issued
22567 an appropriate message. */
22570 {
22573 }
22579 {
22580 /* There is an asymmetry here in the way VAR_DECLs and
22581 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22582 the latter, the DECL we get back will be marked as a
22583 template instantiation, and the appropriate
22584 DECL_TEMPLATE_INFO will be set up. This does not happen for
22585 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22586 should handle VAR_DECLs as it currently handles
22587 FUNCTION_DECLs. */
22589 {
22592 }
22595 {
22598 }
22600 {
22605 }
22606 }
22608 {
22611 }
22612 else
22615 /* Check for various error cases. Note that if the explicit
22616 instantiation is valid the RESULT will currently be marked as an
22617 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22618 until we get here. */
22621 {
22622 /* DR 259 [temp.spec].
22624 Both an explicit instantiation and a declaration of an explicit
22625 specialization shall not appear in a program unless the explicit
22626 instantiation follows a declaration of the explicit specialization.
22628 For a given set of template parameters, if an explicit
22629 instantiation of a template appears after a declaration of an
22630 explicit specialization for that template, the explicit
22631 instantiation has no effect. */
22633 }
22635 {
22636 /* [temp.spec]
22638 No program shall explicitly instantiate any template more
22639 than once.
22641 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22642 the first instantiation was `extern' and the second is not,
22643 and EXTERN_P for the opposite case. */
22646 /* If an "extern" explicit instantiation follows an ordinary
22647 explicit instantiation, the template is instantiated. */
22650 }
22652 {
22655 }
22657 {
22660 }
22663 ;
22665 {
22668 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22671 }
22672 else
22680 }
22682 static void
22684 {
22690 {
22693 }
22694 }
22696 /* Called from do_type_instantiation through binding_table_foreach to
22697 do recursive instantiation for the type bound in ENTRY. */
22698 static void
22700 {
22706 }
22708 /* Perform an explicit instantiation of template class T. STORAGE, if
22709 non-null, is the RID for extern, inline or static. COMPLAIN is
22710 nonzero if this is called from the parser, zero if called recursively,
22711 since the standard is unclear (as detailed below). */
22713 void
22715 {
22725 {
22726 tree tmpl =
22730 else
22733 }
22738 {
22741 t);
22743 }
22746 {
22748 {
22750 {
22753 "ISO C++ 1998 forbids the use of %<extern%> on "
22755 }
22756 else
22758 "ISO C++ forbids the use of %qE"
22760 }
22768 else
22769 {
22771 storage);
22773 }
22774 }
22777 {
22778 /* DR 259 [temp.spec].
22780 Both an explicit instantiation and a declaration of an explicit
22781 specialization shall not appear in a program unless the explicit
22782 instantiation follows a declaration of the explicit specialization.
22784 For a given set of template parameters, if an explicit
22785 instantiation of a template appears after a declaration of an
22786 explicit specialization for that template, the explicit
22787 instantiation has no effect. */
22789 }
22791 {
22792 /* [temp.spec]
22794 No program shall explicitly instantiate any template more
22795 than once.
22797 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22798 instantiation was `extern'. If EXTERN_P then the second is.
22799 These cases are OK. */
22806 /* If we've already instantiated the template, just return now. */
22809 }
22817 /* In contrast to implicit instantiation, where only the
22818 declarations, and not the definitions, of members are
22819 instantiated, we have here:
22821 [temp.explicit]
22823 The explicit instantiation of a class template specialization
22824 implies the instantiation of all of its members not
22825 previously explicitly specialized in the translation unit
22826 containing the explicit instantiation.
22828 Of course, we can't instantiate member template classes, since we
22829 don't have any arguments for them. Note that the standard is
22830 unclear on whether the instantiation of the members are
22831 *explicit* instantiations or not. However, the most natural
22832 interpretation is that it should be an explicit
22833 instantiation. */
22837 && !static_p
22840 {
22845 }
22850 }
22852 /* Given a function DECL, which is a specialization of TMPL, modify
22853 DECL to be a re-instantiation of TMPL with the same template
22854 arguments. TMPL should be the template into which tsubst'ing
22855 should occur for DECL, not the most general template.
22857 One reason for doing this is a scenario like this:
22859 template <class T>
22860 void f(const T&, int i);
22862 void g() { f(3, 7); }
22864 template <class T>
22865 void f(const T& t, const int i) { }
22867 Note that when the template is first instantiated, with
22868 instantiate_template, the resulting DECL will have no name for the
22869 first parameter, and the wrong type for the second. So, when we go
22870 to instantiate the DECL, we regenerate it. */
22872 static void
22874 {
22875 /* The arguments used to instantiate DECL, from the most general
22876 template. */
22877 tree code_pattern;
22881 /* Make sure that we can see identifiers, and compute access
22882 correctly. */
22886 {
22887 tree decl_parm;
22888 tree pattern_parm;
22889 tree specs;
22903 specs);
22905 /* Merge parameter declarations. */
22908 pattern_parm
22912 {
22913 tree parm_type;
22914 tree attributes;
22919 NULL_TREE);
22925 {
22928 }
22931 }
22932 /* Merge any parameters that match with the function parameter
22933 pack. */
22935 {
22937 tree expanded_types;
22938 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22939 the parameters in this function parameter pack. */
22944 {
22945 tree parm_type;
22946 tree attributes;
22949 /* Rename the parameter to include the index. */
22958 {
22961 }
22963 }
22964 }
22965 /* Merge additional specifiers from the CODE_PATTERN. */
22969 }
22971 {
22981 }
22982 else
22986 }
22988 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22989 substituted to get DECL. */
22991 tree
22993 {
22996 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22997 for the instantiation. This is not always the most general
22998 template. Consider, for example:
23000 template <class T>
23001 struct S { template <class U> void f();
23002 template <> void f<int>(); };
23004 and an instantiation of S<double>::f<int>. We want TD to be the
23005 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23007 more general template. */
23009 /* We must also deal with friend templates. Given:
23011 template <class T> struct S {
23012 template <class U> friend void f() {};
23013 };
23015 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23016 so far as the language is concerned, but that's still
23017 where we get the pattern for the instantiation from. On
23018 other hand, if the definition comes outside the class, say:
23020 template <class T> struct S {
23021 template <class U> friend void f();
23022 };
23023 template <class U> friend void f() {}
23025 we don't need to look any further. That's what the check for
23026 DECL_INITIAL is for. */
23030 {
23031 /* The present template, TD, should not be a definition. If it
23032 were a definition, we should be using it! Note that we
23033 cannot restructure the loop to just keep going until we find
23034 a template with a definition, since that might go too far if
23035 a specialization was declared, but not defined. */
23037 /* Fetch the more general template. */
23039 }
23042 }
23044 /* Returns true if we need to instantiate this template instance even if we
23045 know we aren't going to emit it. */
23047 bool
23049 {
23050 /* We always instantiate inline functions so that we can inline them. An
23051 explicit instantiation declaration prohibits implicit instantiation of
23052 non-inline functions. With high levels of optimization, we would
23053 normally inline non-inline functions -- but we're not allowed to do
23054 that for "extern template" functions. Therefore, we check
23055 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23059 /* And we need to instantiate static data members so that
23060 their initializers are available in integral constant
23061 expressions. */
23064 }
23066 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23067 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23068 error, true otherwise. */
23070 bool
23072 {
23075 /* Don't instantiate a noexcept-specification from template context. */
23090 {
23096 {
23097 /* If hash_set::add returns true, the element was already there. */
23102 fn);
23104 }
23106 {
23121 }
23122 else
23132 }
23135 {
23138 else
23140 }
23143 }
23145 /* We're starting to process the function INST, an instantiation of PATTERN;
23146 add their parameters to local_specializations. */
23148 static void
23150 {
23154 {
23158 }
23160 {
23162 {
23165 }
23166 else
23167 {
23168 /* Register the (value) argument pack as a specialization of
23169 TMPL_PARM, then move on. */
23172 }
23173 }
23175 }
23177 /* Produce the definition of D, a _DECL generated from a template. If
23178 DEFER_OK is true, then we don't have to actually do the
23179 instantiation now; we just have to do it sometime. Normally it is
23180 an error if this is an explicit instantiation but D is undefined.
23181 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23182 instantiated class template. */
23184 tree
23186 {
23188 tree gen_args;
23189 tree args;
23190 tree td;
23191 tree code_pattern;
23192 tree spec;
23193 tree gen_tmpl;
23201 /* This function should only be used to instantiate templates for
23202 functions and static member variables. */
23205 /* A concept is never instantiated. */
23208 /* Variables are never deferred; if instantiation is required, they
23209 are instantiated right away. That allows for better code in the
23210 case that an expression refers to the value of the variable --
23211 if the variable has a constant value the referring expression can
23212 take advantage of that fact. */
23216 /* Don't instantiate cloned functions. Instead, instantiate the
23217 functions they cloned. */
23225 /* D has already been instantiated or explicitly specialized, so
23226 there's nothing for us to do here.
23228 It might seem reasonable to check whether or not D is an explicit
23229 instantiation, and, if so, stop here. But when an explicit
23230 instantiation is deferred until the end of the compilation,
23231 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23232 the instantiation. */
23235 /* Check to see whether we know that this template will be
23236 instantiated in some other file, as with "extern template"
23237 extension. */
23240 /* In general, we do not instantiate such templates. */
23248 /* We should already have the extra args. */
23251 /* And what's in the hash table should match D. */
23255 /* This needs to happen before any tsubsting. */
23261 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23262 for the instantiation. */
23267 {
23268 /* Look up an explicit specialization, if any. */
23272 {
23275 }
23276 }
23280 /* We should never be trying to instantiate a member of a class
23281 template or partial specialization. */
23286 /* In the case of a friend template whose definition is provided
23287 outside the class, we may have too many arguments. Drop the
23288 ones we don't need. The same is true for specializations. */
23289 args = get_innermost_template_args
23293 {
23299 }
23300 else
23301 {
23306 else
23308 }
23310 /* We may be in the middle of deferred access check. Disable it now. */
23313 /* Unless an explicit instantiation directive has already determined
23314 the linkage of D, remember that a definition is available for
23315 this entity. */
23325 /* If D is a member of an explicitly instantiated class template,
23326 and no definition is available, treat it like an implicit
23327 instantiation. */
23330 {
23331 /* Leave linkage flags alone on instantiations with anonymous
23332 visibility. */
23334 {
23337 }
23339 }
23341 /* Defer all other templates, unless we have been explicitly
23342 forbidden from doing so. */
23344 template. */
23345 ! pattern_defined
23346 /* If it's OK to postpone instantiation, do so. */
23347 || defer_ok
23348 /* If this is a static data member that will be defined
23349 elsewhere, we don't want to instantiate the entire data
23350 member, but we do want to instantiate the initializer so that
23351 we can substitute that elsewhere. */
23353 /* Handle here a deleted function too, avoid generating
23354 its body (c++/61080). */
23356 {
23357 /* The definition of the static data member is now required so
23358 we must substitute the initializer. */
23362 {
23363 tree ns;
23364 tree init;
23373 args,
23376 /* If instantiating the initializer involved instantiating this
23377 again, don't call cp_finish_decl twice. */
23379 {
23380 /* Make sure the initializer is still constant, in case of
23381 circular dependency (template/instantiate6.C). */
23382 const_init
23386 LOOKUP_ONLYCONVERTING);
23387 }
23391 }
23393 /* We restore the source position here because it's used by
23394 add_pending_template. */
23400 /* [temp.explicit]
23402 The definition of a non-exported function template, a
23403 non-exported member function template, or a non-exported
23404 member function or static data member of a class template
23405 shall be present in every translation unit in which it is
23406 explicitly instantiated. */
23410 /* If we're in unevaluated context, we just wanted to get the
23411 constant value; this isn't an odr use, so don't queue
23412 a full instantiation. */
23415 /* ??? Historically, we have instantiated inline functions, even
23416 when marked as "extern template". */
23420 }
23421 /* Tell the repository that D is available in this translation unit
23422 -- and see if it is supposed to be instantiated here. */
23424 {
23425 /* In a PCH file, despite the fact that the repository hasn't
23426 requested instantiation in the PCH it is still possible that
23427 an instantiation will be required in a file that includes the
23428 PCH. */
23431 /* Instantiate inline functions so that the inliner can do its
23432 job, even though we'll not be emitting a copy of this
23433 function. */
23436 }
23439 tree fn_context;
23450 else
23451 {
23455 }
23457 /* Mark D as instantiated so that recursive calls to
23458 instantiate_decl do not try to instantiate it again. */
23461 /* Regenerate the declaration in case the template has been modified
23462 by a subsequent redeclaration. */
23465 /* We already set the file and line above. Reset them now in case
23466 they changed as a result of calling regenerate_decl_from_template. */
23470 {
23471 tree init;
23474 /* Clear out DECL_RTL; whatever was there before may not be right
23475 since we've reset the type of the declaration. */
23479 /* The initializer is placed in DECL_INITIAL by
23480 regenerate_decl_from_template so we don't need to
23481 push/pop_access_scope again here. Pull it out so that
23482 cp_finish_decl can process it. */
23487 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23488 initializer. That function will defer actual emission until
23489 we have a chance to determine linkage. */
23492 /* Enter the scope of D so that access-checking works correctly. */
23505 }
23509 {
23510 /* Set up the list of local specializations. */
23514 /* Set up context. */
23518 else
23521 /* Some typedefs referenced from within the template code need to be
23522 access checked at template instantiation time, i.e now. These
23523 types were added to the template at parsing time. Let's get those
23524 and perform the access checks then. */
23526 args);
23528 /* Create substitution entries for the parameters. */
23531 /* Substitute into the body of the function. */
23535 else
23536 {
23541 /* Set the current input_location to the end of the function
23542 so that finish_function knows where we are. */
23543 input_location
23546 /* Remember if we saw an infinite loop in the template. */
23547 current_function_infinite_loop
23549 }
23551 /* Finish the function. */
23555 else
23556 {
23559 }
23563 }
23565 /* We're not deferring instantiation any more. */
23570 else
23576 out:
23585 }
23587 /* Run through the list of templates that we wish we could
23588 instantiate, and instantiate any we can. RETRIES is the
23589 number of times we retry pending template instantiation. */
23591 void
23593 {
23597 /* Instantiating templates may trigger vtable generation. This in turn
23598 may require further template instantiations. We place a limit here
23599 to avoid infinite loop. */
23601 {
23605 "template instantiation depth exceeds maximum of %d"
23606 " instantiating %q+D, possibly from virtual table generation"
23610 /* Pretend that we defined it. */
23613 }
23615 do
23616 {
23621 {
23626 {
23628 {
23643 }
23646 }
23647 else
23648 {
23651 {
23652 instantiation
23658 }
23662 }
23665 /* If INSTANTIATION has been instantiated, then we don't
23666 need to consider it again in the future. */
23668 else
23669 {
23672 }
23675 }
23677 }
23681 }
23683 /* Substitute ARGVEC into T, which is a list of initializers for
23684 either base class or a non-static data member. The TREE_PURPOSEs
23685 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23686 instantiate_decl. */
23688 static tree
23690 {
23695 {
23696 tree decl;
23697 tree init;
23703 {
23704 tree expr;
23705 tree arg;
23707 /* Expand the base class expansion type into separate base
23708 classes. */
23710 tf_warning_or_error,
23711 NULL_TREE);
23715 /* We'll be building separate TREE_LISTs of arguments for
23716 each base. */
23722 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23723 expand each argument in the TREE_VALUE of t. */
23730 /* VOID_TYPE_NODE is used to indicate
23731 value-initialization. */
23732 {
23735 }
23736 else
23737 {
23738 /* Substitute parameter packs into each argument in the
23739 TREE_LIST. */
23742 {
23743 tree expanded_exprs;
23745 /* Expand the argument. */
23747 expanded_exprs
23749 tf_warning_or_error,
23750 NULL_TREE);
23754 /* Prepend each of the expanded expressions to the
23755 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23757 {
23762 }
23763 }
23766 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23767 since we built them backwards. */
23769 {
23772 }
23773 }
23774 }
23777 {
23779 {
23783 }
23784 else
23785 {
23786 tree tmp;
23801 /* If we had an initializer but it instantiated to nothing,
23802 value-initialize the object. This will only occur when
23803 the initializer was a pack expansion where the parameter
23804 packs used in that expansion were of length zero. */
23807 }
23811 {
23813 decl);
23815 }
23816 /* Look for a target constructor. */
23820 {
23823 {
23827 }
23829 }
23832 {
23836 }
23837 }
23838 }
23840 }
23842 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23844 static void
23846 {
23851 else
23853 }
23855 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23856 is the instantiation (which should have been created with
23857 start_enum) and ARGS are the template arguments to use. */
23859 static void
23861 {
23862 tree e;
23868 {
23869 tree value;
23870 tree decl;
23873 /* Note that in a template enum, the TREE_VALUE is the
23874 CONST_DECL, not the corresponding INTEGER_CST. */
23879 /* Give this enumeration constant the correct access. */
23882 /* Actually build the enumerator itself. Here we're assuming that
23883 enumerators can't have dependent attributes. */
23886 }
23896 }
23898 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23899 its type -- but without substituting the innermost set of template
23900 arguments. So, innermost set of template parameters will appear in
23901 the type. */
23903 tree
23905 {
23906 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23908 }
23910 /* Return truthvalue if we're processing a template different from
23911 the last one involved in diagnostics. */
23912 bool
23914 {
23916 }
23918 /* Remember current template involved in diagnostics. */
23919 void
23921 {
23923 }
23927 {
23929 }
23931 /* Return TRUE if current_function_decl is being instantiated, false
23932 otherwise. */
23934 bool
23936 {
23939 }
23941 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23942 type. Return false for ok, true for disallowed. Issue error and
23943 inform messages under control of COMPLAIN. */
23945 static bool
23947 {
23962 /* A bound template template parm could later be instantiated to have a valid
23963 nontype parm type via an alias template. */
23969 {
23972 else
23974 type);
23975 }
23977 }
23979 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23980 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23982 static bool
23984 {
23985 tree scope;
23987 /* [temp.dep.type]
23989 A type is dependent if it is:
23991 -- a template parameter. Template template parameters are types
23992 for us (since TYPE_P holds true for them) so we handle
23993 them here. */
23997 /* -- a qualified-id with a nested-name-specifier which contains a
23998 class-name that names a dependent type or whose unqualified-id
23999 names a dependent type. */
24003 /* An alias template specialization can be dependent even if the
24004 resulting type is not. */
24008 /* -- a cv-qualified type where the cv-unqualified type is
24009 dependent.
24010 No code is necessary for this bullet; the code below handles
24011 cv-qualified types, and we don't want to strip aliases with
24012 TYPE_MAIN_VARIANT because of DR 1558. */
24013 /* -- a compound type constructed from any dependent type. */
24023 {
24024 tree arg_type;
24029 arg_type;
24034 /* A value-dependent noexcept-specifier makes the type dependent. */
24037 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24038 affect overload resolution and treating it as dependent breaks
24039 things. */
24044 }
24045 /* -- an array type constructed from any dependent type or whose
24046 size is specified by a constant expression that is
24047 value-dependent.
24049 We checked for type- and value-dependence of the bounds in
24050 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24052 {
24057 }
24059 /* -- a template-id in which either the template name is a template
24060 parameter ... */
24063 /* ... or any of the template arguments is a dependent type or
24064 an expression that is type-dependent or value-dependent. */
24066 && (any_dependent_template_arguments_p
24070 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24071 dependent; if the argument of the `typeof' expression is not
24072 type-dependent, then it should already been have resolved. */
24078 /* A template argument pack is dependent if any of its packed
24079 arguments are. */
24081 {
24087 }
24089 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24090 be template parameters. */
24097 /* The standard does not specifically mention types that are local
24098 to template functions or local classes, but they should be
24099 considered dependent too. For example:
24101 template <int I> void f() {
24102 enum E { a = I };
24103 S<sizeof (E)> s;
24104 }
24106 The size of `E' cannot be known until the value of `I' has been
24107 determined. Therefore, `E' must be considered dependent. */
24111 /* Don't use type_dependent_expression_p here, as it can lead
24112 to infinite recursion trying to determine whether a lambda
24113 nested in a lambda is dependent (c++/47687). */
24117 && (any_dependent_template_arguments_p
24121 /* Other types are non-dependent. */
24123 }
24125 /* Returns TRUE if TYPE is dependent, in the sense of
24126 [temp.dep.type]. Note that a NULL type is considered dependent. */
24128 bool
24130 {
24131 /* If there are no template parameters in scope, then there can't be
24132 any dependent types. */
24134 {
24135 /* If we are not processing a template, then nobody should be
24136 providing us with a dependent type. */
24140 }
24142 /* If the type is NULL, we have not computed a type for the entity
24143 in question; in that case, the type is dependent. */
24147 /* Erroneous types can be considered non-dependent. */
24151 /* Getting here with global_type_node means we improperly called this
24152 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24155 /* If we have not already computed the appropriate value for TYPE,
24156 do so now. */
24158 {
24161 }
24164 }
24166 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24167 lookup. In other words, a dependent type that is not the current
24168 instantiation. */
24170 bool
24172 {
24175 }
24177 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24178 an unknown base of 'this' (and is therefore instantiation-dependent). */
24180 static bool
24182 {
24199 }
24201 /* T is a SCOPE_REF; return whether we need to consider it
24202 instantiation-dependent so that we can check access at instantiation
24203 time even though we know which member it resolves to. */
24205 static bool
24207 {
24214 else
24216 }
24218 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24219 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24220 expression. */
24222 /* Note that this predicate is not appropriate for general expressions;
24223 only constant expressions (that satisfy potential_constant_expression)
24224 can be tested for value dependence. */
24226 bool
24228 {
24232 /* A type-dependent expression is also value-dependent. */
24237 {
24239 /* A dependent member function of the current instantiation. */
24243 /* A dependent member function of the current instantiation. */
24250 /* A name that has not been looked up -- must be dependent. */
24254 /* A non-type template parm. */
24258 /* A non-type template parm. */
24264 /* A constant with literal type and is initialized
24265 with an expression that is value-dependent. */
24267 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24271 {
24275 }
24284 /* These expressions are value-dependent if the type to which
24285 the cast occurs is dependent or the expression being casted
24286 is value-dependent. */
24287 {
24293 /* A functional cast has a list of operands. */
24296 {
24297 /* If there are no operands, it must be an expression such
24298 as "int()". This should not happen for aggregate types
24299 because it would form non-constant expressions. */
24304 }
24310 }
24315 /* FALLTHRU */
24318 /* A `sizeof' expression is value-dependent if the operand is
24319 type-dependent or is a pack expansion. */
24328 /* An 'encode' expression is value-dependent if the operand is
24329 type-dependent. */
24338 /* All instantiation-dependent expressions should also be considered
24339 value-dependent. */
24347 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24348 is value-dependent. */
24349 {
24358 }
24361 {
24378 }
24389 {
24393 }
24396 /* Treat all requires-expressions as value-dependent so
24397 we don't try to fold them. */
24404 {
24411 {
24413 /* In a call to a constexpr member function, look through the
24414 implicit ADDR_EXPR on the object argument so that it doesn't
24415 cause the call to be considered value-dependent. We also
24416 look through it in potential_constant_expression. */
24423 }
24425 }
24431 {
24433 tree val;
24440 }
24443 /* Treat a GNU statement expression as dependent to avoid crashing
24444 under instantiate_non_dependent_expr; it can't be constant. */
24448 /* A constant expression is value-dependent if any subexpression is
24449 value-dependent. */
24451 {
24458 {
24462 {
24465 /* In some cases, some of the operands may be missing.
24466 (For example, in the case of PREDECREMENT_EXPR, the
24467 amount to increment by may be missing.) That doesn't
24468 make the expression dependent. */
24471 }
24472 }
24476 }
24478 }
24480 /* The expression is not value-dependent. */
24482 }
24484 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24485 [temp.dep.expr]. Note that an expression with no type is
24486 considered dependent. Other parts of the compiler arrange for an
24487 expression with type-dependent subexpressions to have no type, so
24488 this function doesn't have to be fully recursive. */
24490 bool
24492 {
24501 /* An unresolved name is always dependent. */
24507 /* A fold expression is type-dependent. */
24514 /* Some expression forms are never type-dependent. */
24528 /* The types of these expressions depends only on the type to which
24529 the cast occurs. */
24538 /* The types of these expressions depends only on the type created
24539 by the expression. */
24542 {
24543 /* For NEW_EXPR tree nodes created inside a template, either
24544 the object type itself or a TREE_LIST may appear as the
24545 operand 1. */
24548 /* This is an array type. We need to check array dimensions
24549 as well. */
24551 || value_dependent_expression_p
24553 else
24555 }
24558 {
24562 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24563 contains an identifier associated by name lookup with one or more
24564 declarations declared with a dependent type, or...a
24565 nested-name-specifier or qualified-id that names a member of an
24566 unknown specialization. */
24569 }
24579 {
24580 tree elt;
24584 {
24587 }
24589 }
24591 /* A static data member of the current instantiation with incomplete
24592 array type is type-dependent, as the definition and specializations
24593 can have different bounds. */
24600 /* An array of unknown bound depending on a variadic parameter, eg:
24602 template<typename... Args>
24603 void foo (Args... args)
24604 {
24605 int arr[] = { args... };
24606 }
24608 template<int... vals>
24609 void bar ()
24610 {
24611 int arr[] = { vals... };
24612 }
24614 If the array has no length and has an initializer, it must be that
24615 we couldn't determine its length in cp_complete_array_type because
24616 it is dependent. */
24624 /* A function or variable template-id is type-dependent if it has any
24625 dependent template arguments. */
24629 {
24630 /* Consider the innermost template arguments, since those are the ones
24631 that come from the template-id; the template arguments for the
24632 enclosing class do not make it type-dependent unless they are used in
24633 the type of the decl. */
24635 && (any_dependent_template_arguments_p
24638 }
24640 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24641 type-dependent. Checking this is important for functions with auto return
24642 type, which looks like a dependent type. */
24651 {
24655 }
24657 /* Always dependent, on the number of arguments if nothing else. */
24662 {
24667 {
24673 }
24674 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24679 {
24684 }
24687 {
24694 }
24704 }
24708 /* Dependent type attributes might not have made it from the decl to
24709 the type yet. */
24715 }
24717 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24718 type-dependent if the expression refers to a member of the current
24719 instantiation and the type of the referenced member is dependent, or the
24720 class member access expression refers to a member of an unknown
24721 specialization.
24723 This function returns true if the OBJECT in such a class member access
24724 expression is of an unknown specialization. */
24726 bool
24728 {
24729 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24730 dependent. */
24735 }
24737 /* walk_tree callback function for instantiation_dependent_expression_p,
24738 below. Returns non-zero if a dependent subexpression is found. */
24740 static tree
24743 {
24745 {
24746 /* We don't have to worry about decltype currently because decltype
24747 of an instantiation-dependent expr is a dependent type. This
24748 might change depending on the resolution of DR 1172. */
24751 }
24754 {
24755 /* Don't treat an argument list as dependent just because it has no
24756 TREE_TYPE. */
24764 /* Handle expressions with type operands. */
24769 {
24774 {
24777 else
24778 {
24781 }
24782 }
24784 }
24788 /* In a template, finish_class_member_access_expr creates a
24789 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24790 type-dependent, so that we can check access control at
24791 instantiation time (PR 42277). See also Core issue 1273. */
24798 else
24801 /* Treat statement-expressions as dependent. */
24805 /* Treat requires-expressions as dependent. */
24810 /* Treat calls to function concepts as dependent. */
24816 /* And variable concepts. */
24823 }
24827 else
24829 }
24831 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24832 sense defined by the ABI:
24834 "An expression is instantiation-dependent if it is type-dependent
24835 or value-dependent, or it has a subexpression that is type-dependent
24836 or value-dependent."
24838 Except don't actually check value-dependence for unevaluated expressions,
24839 because in sizeof(i) we don't care about the value of i. Checking
24840 type-dependence will in turn check value-dependence of array bounds/template
24841 arguments as needed. */
24843 bool
24845 {
24846 tree result;
24857 }
24859 /* As above, but also check value-dependence of the expression as a whole. */
24861 bool
24863 {
24866 }
24868 /* Like type_dependent_expression_p, but it also works while not processing
24869 a template definition, i.e. during substitution or mangling. */
24871 bool
24873 {
24879 }
24881 /* Returns TRUE if ARGS contains a type-dependent expression. */
24883 bool
24885 {
24887 tree arg;
24890 {
24893 }
24895 }
24897 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24898 expressions) contains any type-dependent expressions. */
24900 bool
24902 {
24908 }
24910 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24911 expressions) contains any value-dependent expressions. */
24913 bool
24915 {
24921 }
24923 /* Returns TRUE if the ARG (a template argument) is dependent. */
24925 bool
24927 {
24931 /* Assume a template argument that was wrongly written by the user
24932 is dependent. This is consistent with what
24933 any_dependent_template_arguments_p [that calls this function]
24934 does. */
24944 {
24947 /* A member template of a dependent class is not necessarily
24948 type-dependent, but it is a dependent template argument because it
24949 will be a member of an unknown specialization to that template. */
24952 }
24954 {
24958 {
24961 }
24964 }
24967 else
24970 }
24972 /* Returns true if ARGS (a collection of template arguments) contains
24973 any types that require structural equality testing. */
24975 bool
24977 {
24987 {
24990 {
24996 {
24997 /* Look inside the argument pack. */
25000 }
25003 {
25016 }
25017 }
25018 }
25021 }
25023 /* Returns true if ARGS (a collection of template arguments) contains
25024 any dependent arguments. */
25026 bool
25028 {
25038 {
25043 }
25046 }
25048 /* Returns TRUE if the template TMPL is type-dependent. */
25050 bool
25052 {
25054 {
25059 }
25061 /* Template template parameters are dependent. */
25065 /* So are names that have not been looked up. */
25069 }
25071 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25073 bool
25075 {
25078 }
25080 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25081 are dependent. */
25083 bool
25085 {
25092 {
25114 {
25118 }
25122 {
25126 {
25131 }
25132 }
25133 }
25136 }
25138 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25139 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25140 no such TYPE can be found. Note that this function peers inside
25141 uninstantiated templates and therefore should be used only in
25142 extremely limited situations. ONLY_CURRENT_P restricts this
25143 peering to the currently open classes hierarchy (which is required
25144 when comparing types). */
25146 tree
25148 {
25149 tree scope;
25150 tree name;
25151 tree decl;
25153 tree pushed_scope;
25154 tree result;
25159 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25160 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25161 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25162 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25163 identifier of the TYPENAME_TYPE anymore.
25164 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25165 TYPENAME_TYPE instead, we avoid messing up with a possible
25166 typedef variant case. */
25169 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25170 it first before we can figure out what NAME refers to. */
25172 {
25174 /* Given a class template A with a dependent base with nested type C,
25175 typedef typename A::C::C C will land us here, as trying to resolve
25176 the initial A::C leads to the local C typedef, which leads back to
25177 A::C::C. So we break the recursion now. */
25179 else
25181 }
25182 /* If we don't know what SCOPE refers to, then we cannot resolve the
25183 TYPENAME_TYPE. */
25186 /* If this is a typedef, we don't want to look inside (c++/11987). */
25189 /* If SCOPE isn't the template itself, it will not have a valid
25190 TYPE_FIELDS list. */
25192 /* scope is either the template itself or a compatible instantiation
25193 like X<T>, so look up the name in the original template. */
25195 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25197 /* If scope has no fields, it can't be a current instantiation. Check this
25198 before currently_open_class to avoid infinite recursion (71515). */
25201 /* If the SCOPE is not the current instantiation, there's no reason
25202 to look inside it. */
25205 /* Enter the SCOPE so that name lookup will be resolved as if we
25206 were in the class definition. In particular, SCOPE will no
25207 longer be considered a dependent type. */
25209 /* Look up the declaration. */
25211 tf_warning_or_error);
25215 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25216 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25222 {
25226 }
25229 {
25230 /* Obtain the template and the arguments. */
25233 {
25234 /* We get here with a plain identifier because a previous tentative
25235 parse of the nested-name-specifier as part of a ptr-operator saw
25236 ::template X<A>. The use of ::template is necessary in a
25237 ptr-operator, but wrong in a declarator-id.
25239 [temp.names]: In a qualified-id of a declarator-id, the keyword
25240 template shall not appear at the top level. */
25244 }
25246 /* Instantiate the template. */
25252 }
25254 /* Leave the SCOPE. */
25258 /* If we failed to resolve it, return the original typename. */
25262 /* If lookup found a typename type, resolve that too. */
25264 {
25265 /* Ill-formed programs can cause infinite recursion here, so we
25266 must catch that. */
25270 }
25272 /* Qualify the resulting type. */
25278 }
25280 /* EXPR is an expression which is not type-dependent. Return a proxy
25281 for EXPR that can be used to compute the types of larger
25282 expressions containing EXPR. */
25284 tree
25286 {
25288 tree inner_expr;
25290 /* When checking, try to get a constant value for all non-dependent
25291 expressions in order to expose bugs in *_dependent_expression_p
25292 and constexpr. This can affect code generation, see PR70704, so
25293 only do this for -fchecking=2. */
25296 /* Don't do this during nsdmi parsing as it can lead to
25297 unexpected recursive instantiations. */
25299 /* Don't do this during concept expansion either and for
25300 the same reason. */
25306 /* Preserve OVERLOADs; the functions must be available to resolve
25307 types. */
25318 /* There is no need to return a proxy for a variable. */
25321 /* Preserve string constants; conversions from string constants to
25322 "char *" are allowed, even though normally a "const char *"
25323 cannot be used to initialize a "char *". */
25326 /* Preserve void and arithmetic constants, as an optimization -- there is no
25327 reason to create a new node. */
25332 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25333 There is at least one place where we want to know that a
25334 particular expression is a throw-expression: when checking a ?:
25335 expression, there are special rules if the second or third
25336 argument is a throw-expression. */
25340 /* Don't wrap an initializer list, we need to be able to look inside. */
25344 /* Don't wrap a dummy object, we need to be able to test for it. */
25363 /* If the type is unknown, it can't really be non-dependent */
25366 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25368 }
25370 /* ARGS is a vector of expressions as arguments to a function call.
25371 Replace the arguments with equivalent non-dependent expressions.
25372 This modifies ARGS in place. */
25374 void
25376 {
25378 tree arg;
25381 {
25385 }
25386 }
25388 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25389 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25390 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25392 static tree
25394 {
25408 }
25410 tree
25412 {
25414 }
25416 tree
25418 {
25420 }
25422 /* Return a C++17 deduction placeholder for class template TMPL. */
25424 tree
25426 {
25430 }
25432 /* True iff T is a C++17 class template deduction placeholder. */
25434 bool
25436 {
25438 }
25440 /* Make a "constrained auto" type-specifier. This is an
25441 auto type with constraints that must be associated after
25442 deduction. The constraint is formed from the given
25443 CONC and its optional sequence of arguments, which are
25444 non-null if written as partial-concept-id. */
25446 tree
25448 {
25451 /* Build the constraint. */
25459 /* Our canonical type depends on the constraint. */
25462 /* Attach the constraint to the type declaration. */
25465 }
25467 /* Given type ARG, return std::initializer_list<ARG>. */
25469 static tree
25471 {
25475 {
25479 "deducing from brace-enclosed initializer list"
25483 }
25489 }
25491 /* Replace auto in TYPE with std::initializer_list<auto>. */
25493 static tree
25495 {
25502 }
25504 /* Hash traits for hashing possibly constrained 'auto'
25505 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25508 {
25511 };
25513 /* Hash the 'auto' T. */
25515 inline hashval_t
25517 {
25519 /* Matching constrained-type-specifiers denote the same template
25520 parameter, so hash the constraint. */
25522 else
25523 /* But unconstrained autos are all separate, so just hash the pointer. */
25525 }
25527 /* Compare two 'auto's. */
25531 {
25538 /* Two unconstrained autos are distinct. */
25543 }
25545 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25546 constrained) auto, add it to the vector. */
25548 static int
25550 {
25553 {
25554 /* All the autos were built with index 0; fix that up now. */
25558 /* If this is a repeated constrained-type-specifier, use the index we
25559 chose before. */
25561 else
25562 {
25563 /* Otherwise this is new, so use the current count. */
25566 }
25568 }
25570 /* Always keep walking. */
25572 }
25574 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25575 says they can appear anywhere in the type. */
25577 static tree
25579 {
25588 {
25593 }
25596 }
25598 /* The stem for deduction guide names. */
25601 /* Return the name for a deduction guide for class template TMPL. */
25603 tree
25605 {
25616 }
25618 /* True if NAME is the name of a deduction guide. */
25620 bool
25622 {
25627 }
25629 /* True if FN is a deduction guide. */
25631 bool
25633 {
25638 }
25640 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25642 bool
25644 {
25651 }
25653 /* True if FN is a guide generated from a constructor template. */
25655 bool
25657 {
25665 }
25667 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25668 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25669 template parameter types. Note that the handling of template template
25670 parameters relies on current_template_parms being set appropriately for the
25671 new template. */
25673 static tree
25676 {
25679 tree newtype;
25682 {
25689 }
25690 else
25694 tree newdecl
25699 tree newidx;
25702 {
25712 {
25717 // First create a copy (ttargs) of tsubst_args with an
25718 // additional level for the template template parameter's own
25719 // template parameters (ttparms).
25720 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25728 // Substitute ttargs into ttparms to fix references to
25729 // other template parameters.
25732 // Now substitute again with args based on tparms, to reduce
25733 // the level of the ttparms.
25736 complain);
25737 // Finally, tack the adjusted parms onto tparms.
25739 current_template_parms);
25741 }
25742 }
25743 else
25744 {
25746 tree newconst
25758 }
25761 }
25763 /* Returns a C++17 class deduction guide template based on the constructor
25764 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25765 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25767 static tree
25769 {
25773 location_t loc;
25777 {
25781 {
25784 }
25785 else
25795 }
25796 else
25797 {
25800 fn_tmpl
25810 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25811 fully specialized args for the enclosing class. Strip those off, as
25812 the deduction guide won't have those template parameters. */
25815 /* Discard the 'this' parameter. */
25823 {
25826 /* For a member template constructor, we need to flatten the two
25827 template parameter lists into one, and then adjust the function
25828 signature accordingly. This gets...complicated. */
25831 /* For a member template we should have two levels of parms/args, one
25832 for the class and one for the constructor. We stripped
25833 specialized args for further enclosing classes above. */
25837 /* Template args for translating references to the two-level template
25838 parameters into references to the one-level template parameters we
25839 are creating. */
25844 /* Template parms for the constructor template. */
25847 /* Template parms for the class template. */
25851 /* Template parms for the deduction guide start as a copy of the
25852 template parms for the class. We set current_template_parms for
25853 lookup_template_class_1. */
25859 /* Now we need to rewrite the constructor parms to append them to the
25860 class parms. */
25862 {
25877 }
25879 /* Now we have a final set of template parms to substitute into the
25880 function signature. */
25889 }
25891 }
25894 {
25895 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25899 }
25903 FUNCTION_DECL,
25920 }
25922 /* Deduce template arguments for the class template placeholder PTYPE for
25923 template TMPL based on the initializer INIT, and return the resulting
25924 type. */
25926 static tree
25928 tsubst_flags_t complain)
25929 {
25931 {
25932 /* We should have handled this in the caller. */
25938 }
25949 {
25952 {
25953 /* As an exception, the first phase in 16.3.1.7 (considering the
25954 initializer list as a single argument) is omitted if the
25955 initializer list consists of a single expression of type cv U,
25956 where U is a specialization of C or a class derived from a
25957 specialization of C. */
25968 }
25971 else
25973 }
25974 else
25985 /* Prune explicit deduction guides in copy-initialization context. */
25987 {
25993 {
25994 /* Found a nonconverting guide, prune the candidates. */
26001 }
26002 }
26007 {
26010 }
26013 // FIXME cache artificial deduction guides
26015 {
26020 else
26024 }
26028 /* If this is list-initialization and the class has a list constructor, first
26029 try deducing from the list as a single argument, as [over.match.list]. */
26033 {
26037 }
26039 {
26045 {
26046 /* That didn't work, now try treating the list as a sequence of
26047 arguments. */
26050 }
26051 }
26053 /* Maybe generate an implicit deduction guide. */
26055 {
26059 /* Generate a copy guide. */
26062 /* Generate a default guide. */
26066 {
26069 }
26070 }
26073 {
26075 " of %qT, as it has no non-explicit deduction guides or "
26078 }
26080 {
26084 }
26087 {
26091 }
26094 {
26104 }
26109 }
26111 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26112 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26113 The CONTEXT determines the context in which auto deduction is performed
26114 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26115 OUTER_TARGS are used during template argument deduction
26116 (context == adc_unify) to properly substitute the result, and is ignored
26117 in other contexts.
26119 For partial-concept-ids, extra args may be appended to the list of deduced
26120 template arguments prior to determining constraint satisfaction. */
26122 tree
26126 {
26127 tree targs;
26134 /* Defining a subset of type-dependent expressions that we can deduce
26135 from ahead of time isn't worth the trouble. */
26138 /* Similarly, we can't deduce from another undeduced decl. */
26143 /* C++17 class template argument deduction. */
26147 /* Nothing we can do with this, even in deduction context. */
26150 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26151 with either a new invented type template parameter U or, if the
26152 initializer is a braced-init-list (8.5.4), with
26153 std::initializer_list<U>. */
26155 {
26160 else
26161 {
26163 {
26167 "for deduction to %<std::initializer_list%>, use copy-"
26169 }
26171 }
26172 }
26183 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26184 and initializer has array type, deduce cv-qualified array type. */
26186 complain);
26188 {
26197 {
26201 }
26202 }
26203 else
26204 {
26206 tree tparms;
26210 else
26211 {
26215 }
26222 {
26224 /* Try again at instantiation time. */
26228 /* If type is error_mark_node a diagnostic must have been
26229 emitted by now. Also, having a mention to '<type error>'
26230 in the diagnostic is not really useful to the user. */
26231 {
26235 else
26240 }
26242 }
26243 }
26245 /* Check any placeholder constraints against the deduced type. */
26248 {
26249 /* Use the deduced type to check the associated constraints. If we
26250 have a partial-concept-id, rebuild the argument list so that
26251 we check using the extra arguments. */
26255 {
26258 }
26259 else
26262 {
26264 {
26266 {
26284 }
26286 }
26288 }
26289 }
26295 }
26297 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26298 result. */
26300 tree
26302 {
26304 {
26310 /* In an abbreviated function template we didn't know we were dealing
26311 with a function template when we saw the auto return type, so update
26312 it to have the correct level. */
26314 }
26316 }
26318 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26319 'decltype(auto)' or a deduced class template. */
26321 bool
26323 {
26329 else
26331 }
26333 /* for_each_template_parm callback for type_uses_auto. */
26335 int
26337 {
26339 }
26341 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26342 a use of `auto'. Returns NULL_TREE otherwise. */
26344 tree
26346 {
26350 {
26351 /* The Concepts TS allows multiple autos in one type-specifier; just
26352 return the first one we find, do_auto_deduction will collect all of
26353 them. */
26357 else
26359 }
26360 else
26362 }
26364 /* For a given template T, return the vector of typedefs referenced
26365 in T for which access check is needed at T instantiation time.
26366 T is either a FUNCTION_DECL or a RECORD_TYPE.
26367 Those typedefs were added to T by the function
26368 append_type_to_template_for_access_check. */
26372 {
26373 tree ti;
26384 {
26389 }
26392 }
26394 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26395 tied to T. That list of typedefs will be access checked at
26396 T instantiation time.
26397 T is either a FUNCTION_DECL or a RECORD_TYPE.
26398 TYPE_DECL is a TYPE_DECL node representing a typedef.
26399 SCOPE is the scope through which TYPE_DECL is accessed.
26400 LOCATION is the location of the usage point of TYPE_DECL.
26402 This function is a subroutine of
26403 append_type_to_template_for_access_check. */
26405 static void
26407 tree type_decl,
26408 tree scope,
26409 location_t location)
26410 {
26411 qualified_typedef_usage_t typedef_usage;
26412 tree ti;
26419 && type_decl
26433 }
26435 /* Append TYPE_DECL to the template TEMPL.
26436 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26437 At TEMPL instanciation time, TYPE_DECL will be checked to see
26438 if it can be accessed through SCOPE.
26439 LOCATION is the location of the usage point of TYPE_DECL.
26441 e.g. consider the following code snippet:
26443 class C
26444 {
26445 typedef int myint;
26446 };
26448 template<class U> struct S
26449 {
26450 C::myint mi; // <-- usage point of the typedef C::myint
26451 };
26453 S<char> s;
26455 At S<char> instantiation time, we need to check the access of C::myint
26456 In other words, we need to check the access of the myint typedef through
26457 the C scope. For that purpose, this function will add the myint typedef
26458 and the scope C through which its being accessed to a list of typedefs
26459 tied to the template S. That list will be walked at template instantiation
26460 time and access check performed on each typedefs it contains.
26461 Note that this particular code snippet should yield an error because
26462 myint is private to C. */
26464 void
26466 tree type_decl,
26467 tree scope,
26468 location_t location)
26469 {
26475 /* Make sure we don't append the type to the template twice. */
26482 }
26484 /* Convert the generic type parameters in PARM that match the types given in the
26485 range [START_IDX, END_IDX) from the current_template_parms into generic type
26486 packs. */
26488 tree
26490 {
26501 {
26502 /* Create a distinct parameter pack type from the current parm and add it
26503 to the replacement args to tsubst below into the generic function
26504 parameter. */
26519 }
26525 /* If there are more levels then build up the replacement with the outer
26526 template parms. */
26530 replacement);
26533 }
26535 /* Entries in the decl_constraint hash table. */
26537 {
26538 tree decl;
26539 tree ci;
26540 };
26542 /* Hashing function and equality for constraint entries. */
26544 {
26546 {
26548 }
26551 {
26553 }
26554 };
26556 /* A mapping from declarations to constraint information. Note that
26557 both templates and their underlying declarations are mapped to the
26558 same constraint information.
26560 FIXME: This is defined in pt.c because garbage collection
26561 code is not being generated for constraint.cc. */
26565 /* Returns the template constraints of declaration T. If T is not
26566 constrained, return NULL_TREE. Note that T must be non-null. */
26568 tree
26570 {
26581 else
26583 }
26585 /* Associate the given constraint information CI with the declaration
26586 T. If T is a template, then the constraints are associated with
26587 its underlying declaration. Don't build associations if CI is
26588 NULL_TREE. */
26590 void
26592 {
26604 }
26606 /* Remove the associated constraints of the declaration T. */
26608 void
26610 {
26619 }
26621 /* Memoized satisfaction results for declarations. This
26622 maps the pair (constraint_info, arguments) to the result computed
26623 by constraints_satisfied_p. */
26626 {
26627 tree ci;
26628 tree args;
26629 tree result;
26630 };
26632 /* Hashing function and equality for constraint entries. */
26635 {
26637 {
26640 }
26643 {
26645 }
26646 };
26648 /* Memoized satisfaction results for concept checks. */
26651 {
26652 tree tmpl;
26653 tree args;
26654 tree result;
26655 };
26657 /* Hashing function and equality for constraint entries. */
26660 {
26662 {
26664 }
26667 {
26672 }
26673 };
26678 /* Search for a memoized satisfaction result. Returns one of the
26679 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26681 tree
26683 {
26688 else
26690 }
26692 /* Memoize the result of a satisfication test. Returns the saved result. */
26694 tree
26696 {
26703 }
26705 /* Search for a memoized satisfaction result for a concept. */
26707 tree
26709 {
26714 else
26716 }
26718 /* Memoize the result of a concept check. Returns the saved result. */
26720 tree
26722 {
26729 }
26733 /* Returns a prior concept specialization. This returns the substituted
26734 and normalized constraints defined by the concept. */
26736 tree
26738 {
26743 else
26745 }
26747 /* Save a concept expansion for later. */
26749 tree
26751 {
26758 }
26760 static hashval_t
26762 {
26771 }
26773 /* Compare the constraints of two subsumption entries. The LEFT1 and
26774 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26775 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26777 static bool
26779 {
26787 }
26789 /* Key/value pair for learning and memoizing subsumption results. This
26790 associates a pair of check constraints (including arguments) with
26791 a boolean value indicating the result. */
26794 {
26795 tree t1;
26796 tree t2;
26798 };
26800 /* Hashing function and equality for constraint entries. */
26803 {
26805 {
26807 }
26810 {
26815 }
26816 };
26820 /* Search for a previously cached subsumption result. */
26824 {
26829 else
26831 }
26833 /* Save a subsumption result. */
26835 bool
26837 {
26844 }
26846 /* Set up the hash table for constraint association. */
26848 void
26850 {
26859 }
26861 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26862 0..N-1. */
26864 void
26866 {
26869 integer_type_node,
26870 NULL_TREE),
26874 }
26876 /* Set up the hash tables for template instantiations. */
26878 void
26880 {
26886 }
26888 /* Print stats about the template hash tables for -fstats. */
26890 void
26892 {
26901 }
26903 #if CHECKING_P
26907 /* Verify that build_non_dependent_expr () works, for various expressions,
26908 and that location wrappers don't affect the results. */
26910 static void
26912 {
26915 /* Verify constants, without and with location wrappers. */
26932 }
26934 /* Verify that type_dependent_expression_p () works correctly, even
26935 in the presence of location wrapper nodes. */
26937 static void
26939 {
26944 /* If no templates are involved, nothing is type-dependent. */
26950 /* Within a template, an unresolved name is always type-dependent. */
26953 /* Ensure it copes with NULL_TREE and errors. */
26957 /* A USING_DECL in a template should be type-dependent, even if wrapped
26958 with a location wrapper (PR c++/83799). */
26967 }
26969 /* Run all of the selftests within this file. */
26971 void
26973 {
26976 }