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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2016 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". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
210 location_t);
219 /* Make the current scope suitable for access checking when we are
220 processing T. T can be FUNCTION_DECL for instantiated function
221 template, VAR_DECL for static member variable, or TYPE_DECL for
222 alias template (needed by instantiate_decl). */
224 static void
226 {
234 else
238 {
239 saved_access_scope = tree_cons
242 }
243 }
245 /* Restore the scope set up by push_access_scope. T is the node we
246 are processing. */
248 static void
250 {
252 {
255 }
259 else
261 }
263 /* Do any processing required when DECL (a member template
264 declaration) is finished. Returns the TEMPLATE_DECL corresponding
265 to DECL, unless it is a specialization, in which case the DECL
266 itself is returned. */
268 tree
270 {
277 {
278 tree type;
286 {
290 }
292 }
296 {
298 {
301 }
302 else
304 }
305 else
309 }
311 /* Create a template info node. */
313 tree
315 {
320 }
322 /* Return the template info node corresponding to T, whatever T is. */
324 tree
326 {
348 }
350 /* Returns the template nesting level of the indicated class TYPE.
352 For example, in:
353 template <class T>
354 struct A
355 {
356 template <class U>
357 struct B {};
358 };
360 A<T>::B<U> has depth two, while A<T> has depth one.
361 Both A<T>::B<int> and A<int>::B<U> have depth one, if
362 they are instantiations, not specializations.
364 This function is guaranteed to return 0 if passed NULL_TREE so
365 that, for example, `template_class_depth (current_class_type)' is
366 always safe. */
368 int
370 {
374 {
385 else
387 }
390 }
392 /* Subroutine of maybe_begin_member_template_processing.
393 Returns true if processing DECL needs us to push template parms. */
395 static bool
397 {
403 }
405 /* Subroutine of maybe_begin_member_template_processing.
406 Push the template parms in PARMS, starting from LEVELS steps into the
407 chain, and ending at the beginning, since template parms are listed
408 innermost first. */
410 static void
412 {
420 current_template_parms
426 NULL);
428 {
437 {
444 /* Push the CONST_DECL. */
450 }
451 }
452 }
454 /* Restore the template parameter context for a member template, a
455 friend template defined in a class definition, or a non-template
456 member of template class. */
458 void
460 {
461 tree parms;
466 {
469 /* Disregard full specializations (c++/60999). */
472 }
475 {
480 {
483 }
486 }
488 /* Remember how many levels of template parameters we pushed so that
489 we can pop them later. */
491 }
493 /* Undo the effects of maybe_begin_member_template_processing. */
495 void
497 {
506 {
510 }
511 }
513 /* Return a new template argument vector which contains all of ARGS,
514 but has as its innermost set of arguments the EXTRA_ARGS. */
516 static tree
518 {
519 tree new_args;
537 }
539 /* Like add_to_template_args, but only the outermost ARGS are added to
540 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
541 (EXTRA_ARGS) levels are added. This function is used to combine
542 the template arguments from a partial instantiation with the
543 template arguments used to attain the full instantiation from the
544 partial instantiation. */
546 static tree
548 {
549 tree new_args;
551 /* If there are more levels of EXTRA_ARGS than there are ARGS,
552 something very fishy is going on. */
555 /* If *all* the new arguments will be the EXTRA_ARGS, just return
556 them. */
560 /* For the moment, we make ARGS look like it contains fewer levels. */
565 /* Now, we restore ARGS to its full dimensions. */
569 }
571 /* Return the N levels of innermost template arguments from the ARGS. */
573 tree
575 {
576 tree new_args;
582 /* If N is 1, just return the innermost set of template arguments. */
586 /* If we're not removing anything, just return the arguments we were
587 given. */
593 /* Make a new set of arguments, not containing the outer arguments. */
600 }
602 /* The inverse of get_innermost_template_args: Return all but the innermost
603 EXTRA_LEVELS levels of template arguments from the ARGS. */
605 static tree
607 {
608 tree new_args;
614 /* If N is 1, just return the outermost set of template arguments. */
618 /* If we're not removing anything, just return the arguments we were
619 given. */
624 /* Make a new set of arguments, not containing the inner arguments. */
631 }
633 /* We've got a template header coming up; push to a new level for storing
634 the parms. */
636 void
638 {
639 /* We use a non-tag-transparent scope here, which causes pushtag to
640 put tags in this scope, rather than in the enclosing class or
641 namespace scope. This is the right thing, since we want
642 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
643 global template class, push_template_decl handles putting the
644 TEMPLATE_DECL into top-level scope. For a nested template class,
645 e.g.:
647 template <class T> struct S1 {
648 template <class T> struct S2 {};
649 };
651 pushtag contains special code to call pushdecl_with_scope on the
652 TEMPLATE_DECL for S2. */
658 /* Add a dummy parameter level while we process the parameter list. */
659 current_template_parms
662 current_template_parms);
663 }
665 /* This routine is called when a specialization is declared. If it is
666 invalid to declare a specialization here, an error is reported and
667 false is returned, otherwise this routine will return true. */
669 static bool
671 {
674 /* [temp.expl.spec]
676 An explicit specialization shall be declared in the namespace of
677 which the template is a member, or, for member templates, in the
678 namespace of which the enclosing class or enclosing class
679 template is a member. An explicit specialization of a member
680 function, member class or static data member of a class template
681 shall be declared in the namespace of which the class template
682 is a member. */
684 {
687 }
689 /* [temp.expl.spec]
691 In an explicit specialization declaration for a member of a class
692 template or a member template that appears in namespace scope,
693 the member template and some of its enclosing class templates may
694 remain unspecialized, except that the declaration shall not
695 explicitly specialize a class member template if its enclosing
696 class templates are not explicitly specialized as well. */
698 {
701 }
704 }
706 /* We've just seen template <>. */
708 bool
710 {
714 }
716 /* Called at then end of processing a declaration preceded by
717 template<>. */
719 void
721 {
724 }
726 /* Any template <>'s that we have seen thus far are not referring to a
727 function specialization. */
729 void
731 {
734 }
736 /* We've just seen a template header. If SPECIALIZATION is nonzero,
737 it was of the form template <>. */
739 static void
741 {
743 template_header_count++;
744 }
746 /* We're beginning an explicit instantiation. */
748 void
750 {
753 }
756 void
758 {
761 }
763 /* An explicit specialization or partial specialization of TMPL is being
764 declared. Check that the namespace in which the specialization is
765 occurring is permissible. Returns false iff it is invalid to
766 specialize TMPL in the current namespace. */
768 static bool
770 {
773 /* [tmpl.expl.spec]
775 An explicit specialization shall be declared in a namespace enclosing the
776 specialized template. An explicit specialization whose declarator-id is
777 not qualified shall be declared in the nearest enclosing namespace of the
778 template, or, if the namespace is inline (7.3.1), any namespace from its
779 enclosing namespace set. */
782 {
785 }
790 /* Same or enclosing namespace. */
792 else
793 {
799 }
800 }
802 /* SPEC is an explicit instantiation. Check that it is valid to
803 perform this explicit instantiation in the current namespace. */
805 static void
807 {
808 tree ns;
810 /* DR 275: An explicit instantiation shall appear in an enclosing
811 namespace of its template. */
817 }
819 // Returns the type of a template specialization only if that
820 // specialization needs to be defined. Otherwise (e.g., if the type has
821 // already been defined), the function returns NULL_TREE.
822 static tree
824 {
825 // An implicit instantiation of an incomplete type implies
826 // the definition of a new class template.
827 //
828 // template<typename T>
829 // struct S;
830 //
831 // template<typename T>
832 // struct S<T*>;
833 //
834 // Here, S<T*> is an implicit instantiation of S whose type
835 // is incomplete.
839 // It can also be the case that TYPE is a completed specialization.
840 // Continuing the previous example, suppose we also declare:
841 //
842 // template<typename T>
843 // requires Integral<T>
844 // struct S<T*>;
845 //
846 // Here, S<T*> refers to the specialization S<T*> defined
847 // above. However, we need to differentiate definitions because
848 // we intend to define a new partial specialization. In this case,
849 // we rely on the fact that the constraints are different for
850 // this declaration than that above.
851 //
852 // Note that we also get here for injected class names and
853 // late-parsed template definitions. We must ensure that we
854 // do not create new type declarations for those cases.
856 {
860 // If there are no template parameters, this cannot be a new
861 // partial template specializtion?
865 // The injected-class-name is not a new partial specialization.
869 // If the constraints are not the same as those of the primary
870 // then, we can probably create a new specialization.
874 {
878 }
880 // Also, if there's a pre-existing specialization with matching
881 // constraints, then this also isn't new.
884 {
892 }
894 // Create a new type node (and corresponding type decl)
895 // for the newly declared specialization.
900 /* We only need a separate type node for storing the definition of this
901 partial specialization; uses of S<T*> are unconstrained, so all are
902 equivalent. So keep TYPE_CANONICAL the same. */
905 // Build the corresponding type decl.
911 }
914 }
916 /* The TYPE is being declared. If it is a template type, that means it
917 is a partial specialization. Do appropriate error-checking. */
919 tree
921 {
922 tree context;
927 /* A lambda that appears in specialization context is not itself a
928 specialization. */
933 {
937 }
942 {
947 else
950 }
952 {
953 /* This is for ordinary explicit specialization and partial
954 specialization of a template class such as:
956 template <> class C<int>;
958 or:
960 template <class T> class C<T*>;
962 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
965 {
972 {
977 }
978 }
984 /* Trying to define a specialization either without a template<> header
985 or in an inappropriate place. We've already given an error, so just
986 bail now so we don't actually define the specialization. */
988 }
994 {
995 /* This is for an explicit specialization of member class
996 template according to [temp.expl.spec/18]:
998 template <> template <class U> class C<int>::D;
1000 The context `C<int>' must be an implicit instantiation.
1001 Otherwise this is just a member class template declared
1002 earlier like:
1004 template <> class C<int> { template <class U> class D; };
1005 template <> template <class U> class C<int>::D;
1007 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1008 while in the second case, `C<int>::D' is a primary template
1009 and `C<T>::D' may not exist. */
1013 {
1014 tree t;
1019 {
1024 }
1026 /* Check for invalid specialization after instantiation:
1028 template <> template <> class C<int>::D<int>;
1029 template <> template <class U> class C<int>::D; */
1033 {
1037 {
1038 /* We already have a full specialization of this partial
1039 instantiation, or a full specialization has been
1040 looked up but not instantiated. Reassign it to the
1041 new member specialization template. */
1042 spec_entry elt;
1054 spec_entry **slot
1059 }
1060 else
1061 /* But if we've had an implicit instantiation, that's a
1062 problem ([temp.expl.spec]/6). */
1065 }
1067 /* Mark TYPE as a specialization. And as a result, we only
1068 have one level of template argument for the innermost
1069 class template. */
1074 }
1075 }
1077 {
1078 /* Someday C++0x may allow for enum template specialization. */
1083 else
1084 {
1087 }
1088 }
1091 }
1093 /* Returns nonzero if we can optimize the retrieval of specializations
1094 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1095 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1099 {
1102 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1103 parameter. */
1105 /* The optimized lookup depends on the fact that the
1106 template arguments for the member function template apply
1107 purely to the containing class, which is not true if the
1108 containing class is an explicit or partial
1109 specialization. */
1113 /* It is possible to have a template that is not a member
1114 template and is not a member of a template class:
1116 template <typename T>
1117 struct S { friend A::f(); };
1119 Here, the friend function is a template, but the context does
1120 not have template information. The optimized lookup relies
1121 on having ARGS be the template arguments for both the class
1122 and the function template. */
1124 }
1126 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1127 gone through coerce_template_parms by now. */
1129 static void
1131 {
1134 {
1137 {
1144 /* Allow typedefs on the type of a non-type argument, since a
1146 else
1148 }
1149 }
1151 }
1153 /* Retrieve the specialization (in the sense of [temp.spec] - a
1154 specialization is either an instantiation or an explicit
1155 specialization) of TMPL for the given template ARGS. If there is
1156 no such specialization, return NULL_TREE. The ARGS are a vector of
1157 arguments, or a vector of vectors of arguments, in the case of
1158 templates with more than one level of parameters.
1160 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1161 then we search for a partial specialization matching ARGS. This
1162 parameter is ignored if TMPL is not a class template.
1164 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1165 result is a NONTYPE_ARGUMENT_PACK. */
1167 static tree
1169 {
1179 /* There should be as many levels of arguments as there are
1180 levels of parameters. */
1190 {
1191 tree class_template;
1192 tree class_specialization;
1194 tree fns;
1197 /* The template arguments actually apply to the containing
1198 class. Find the class specialization with those
1199 arguments. */
1201 class_specialization
1205 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1206 for the specialization. */
1210 /* Iterate through the methods with the indicated name, looking
1211 for the one that has an instance of TMPL. */
1214 {
1217 /* using-declarations can add base methods to the method vec,
1218 and we don't want those here. */
1221 }
1223 }
1224 else
1225 {
1227 spec_entry elt;
1236 else
1244 }
1247 }
1249 /* Like retrieve_specialization, but for local declarations. */
1251 tree
1253 {
1259 }
1261 /* Returns nonzero iff DECL is a specialization of TMPL. */
1263 int
1265 {
1266 tree t;
1269 {
1275 }
1276 else
1277 {
1286 }
1289 }
1291 /* Returns nonzero iff DECL is a specialization of friend declaration
1292 FRIEND_DECL according to [temp.friend]. */
1294 bool
1296 {
1303 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1304 of a template class, we want to check if DECL is a specialization
1305 if this. */
1309 {
1310 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1313 }
1318 /* There is nothing to do if this is not a template friend. */
1325 /* [temp.friend/6]
1326 A member of a class template may be declared to be a friend of a
1327 non-template class. In this case, the corresponding member of
1328 every specialization of the class template is a friend of the
1329 class granting friendship.
1331 For example, given a template friend declaration
1333 template <class T> friend void A<T>::f();
1335 the member function below is considered a friend
1337 template <> struct A<int> {
1338 void f();
1339 };
1341 For this type of template friend, TEMPLATE_DEPTH below will be
1342 nonzero. To determine if DECL is a friend of FRIEND, we first
1343 check if the enclosing class is a specialization of another. */
1350 {
1351 /* Next, we check the members themselves. In order to handle
1352 a few tricky cases, such as when FRIEND_DECL's are
1354 template <class T> friend void A<T>::g(T t);
1355 template <class T> template <T t> friend void A<T>::h();
1357 and DECL's are
1359 void A<int>::g(int);
1360 template <int> void A<int>::h();
1362 we need to figure out ARGS, the template arguments from
1363 the context of DECL. This is required for template substitution
1364 of `T' in the function parameter of `g' and template parameter
1365 of `h' in the above examples. Here ARGS corresponds to `int'. */
1372 {
1374 {
1377 else
1379 current_depth++;
1380 }
1382 }
1385 {
1387 tree friend_type;
1388 tree decl_type;
1389 tree friend_args_type;
1390 tree decl_args_type;
1392 /* Make sure that both DECL and FRIEND_DECL are templates or
1393 non-templates. */
1399 {
1400 /* If both are templates, check template parameter list. */
1401 tree friend_parms
1406 friend_parms))
1410 }
1411 else
1419 /* Check if return types match. */
1423 /* Check if function parameter types match, ignoring the
1424 `this' parameter. */
1433 }
1434 else
1435 {
1436 /* DECL is a TYPE_DECL */
1440 /* Make sure that both DECL and FRIEND_DECL are templates or
1441 non-templates. */
1442 is_template
1449 {
1450 tree friend_parms;
1451 /* If both are templates, check the name of the two
1452 TEMPLATE_DECL's first because is_friend didn't. */
1457 /* Now check template parameter list. */
1458 friend_parms
1461 return comp_template_parms
1463 friend_parms);
1464 }
1465 else
1468 }
1469 }
1471 }
1473 /* Register the specialization SPEC as a specialization of TMPL with
1474 the indicated ARGS. IS_FRIEND indicates whether the specialization
1475 is actually just a friend declaration. Returns SPEC, or an
1476 equivalent prior declaration, if available.
1478 We also store instantiations of field packs in the hash table, even
1479 though they are not themselves templates, to make lookup easier. */
1481 static tree
1483 hashval_t hash)
1484 {
1485 tree fn;
1487 spec_entry elt;
1495 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1496 register it; we want the corresponding TEMPLATE_DECL instead.
1497 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1498 the more obvious `uses_template_parms (spec)' to avoid problems
1499 with default function arguments. In particular, given
1500 something like this:
1502 template <class T> void f(T t1, T t = T())
1504 the default argument expression is not substituted for in an
1505 instantiation unless and until it is actually needed. */
1509 /* We don't put these specializations in the hash table, but we might
1510 want to give an error about a mismatch. */
1512 else
1513 {
1521 slot =
1525 else
1527 }
1529 /* We can sometimes try to re-register a specialization that we've
1530 already got. In particular, regenerate_decl_from_template calls
1531 duplicate_decls which will update the specialization list. But,
1532 we'll still get called again here anyhow. It's more convenient
1533 to simply allow this than to try to prevent it. */
1537 {
1539 {
1542 {
1544 fn);
1546 }
1547 else
1548 {
1549 tree clone;
1550 /* This situation should occur only if the first
1551 specialization is an implicit instantiation, the
1552 second is an explicit specialization, and the
1553 implicit instantiation has not yet been used. That
1554 situation can occur if we have implicitly
1555 instantiated a member function and then specialized
1556 it later.
1558 We can also wind up here if a friend declaration that
1559 looked like an instantiation turns out to be a
1560 specialization:
1562 template <class T> void foo(T);
1563 class S { friend void foo<>(int) };
1564 template <> void foo(int);
1566 We transform the existing DECL in place so that any
1567 pointers to it become pointers to the updated
1568 declaration.
1570 If there was a definition for the template, but not
1571 for the specialization, we want this to look as if
1572 there were no definition, and vice versa. */
1575 /* The call to duplicate_decls will have applied
1576 [temp.expl.spec]:
1578 An explicit specialization of a function template
1579 is inline only if it is explicitly declared to be,
1580 and independently of whether its function template
1581 is.
1583 to the primary function; now copy the inline bits to
1584 the various clones. */
1586 {
1593 }
1597 }
1598 }
1600 {
1602 /* Dup decl failed, but this is a new definition. Set the
1603 line number so any errors match this new
1604 definition. */
1608 }
1609 }
1613 /* A specialization must be declared in the same namespace as the
1614 template it is specializing. */
1620 {
1629 /* If TMPL is a forward declaration of a template function, keep a list
1630 of all specializations in case we need to reassign them to a friend
1631 template later in tsubst_friend_function.
1633 Also keep a list of all variable template instantiations so that
1634 process_partial_specialization can check whether a later partial
1635 specialization would have used it. */
1638 }
1641 }
1643 /* Returns true iff two spec_entry nodes are equivalent. */
1647 bool
1649 {
1656 /* tmpl could be a FIELD_DECL for a capture pack. */
1660 {
1661 /* Partial specializations of a variable template can be distinguished by
1662 constraints. */
1666 }
1670 }
1672 /* Returns a hash for a template TMPL and template arguments ARGS. */
1674 static hashval_t
1676 {
1679 }
1681 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1682 ignoring SPEC. */
1684 hashval_t
1686 {
1688 }
1690 /* Recursively calculate a hash value for a template argument ARG, for use
1691 in the hash tables of template specializations. */
1693 hashval_t
1695 {
1715 {
1723 {
1728 }
1750 {
1754 {
1757 }
1759 }
1763 {
1766 }
1777 val = iterative_hash_template_arg
1789 val);
1791 val);
1800 /* A lambda can't appear in a template arg, but don't crash on
1801 erroneous input. */
1813 /* Now hash operands as usual. */
1818 }
1821 {
1824 {
1825 // We want an alias specialization that survived strip_typedefs
1826 // to hash differently from its TYPE_CANONICAL, to avoid hash
1827 // collisions that compare as different in template_args_equal.
1828 // These could be dependent specializations that strip_typedefs
1829 // left alone, or untouched specializations because
1830 // coerce_template_parms returns the unconverted template
1831 // arguments if it sees incomplete argument packs.
1834 }
1837 val);
1840 /* Otherwise just compare the types during lookup. */
1849 {
1854 }
1855 }
1858 }
1860 /* Unregister the specialization SPEC as a specialization of TMPL.
1861 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1862 if the SPEC was listed as a specialization of TMPL.
1864 Note that SPEC has been ggc_freed, so we can't look inside it. */
1866 bool
1868 {
1870 spec_entry elt;
1878 {
1883 }
1886 }
1888 /* Like register_specialization, but for local declarations. We are
1889 registering SPEC, an instantiation of TMPL. */
1891 void
1893 {
1895 }
1897 /* TYPE is a class type. Returns true if TYPE is an explicitly
1898 specialized class. */
1900 bool
1902 {
1906 }
1908 /* Print the list of functions at FNS, going through all the overloads
1909 for each element of the list. Alternatively, FNS can not be a
1910 TREE_LIST, in which case it will be printed together with all the
1911 overloads.
1913 MORE and *STR should respectively be FALSE and NULL when the function
1914 is called from the outside. They are used internally on recursive
1915 calls. print_candidates manages the two parameters and leaves NULL
1916 in *STR when it ends. */
1918 static void
1920 {
1926 {
1930 }
1931 else
1932 {
1935 {
1936 /* Pick the prefix string. */
1938 {
1942 }
1946 }
1949 }
1952 {
1955 }
1956 }
1958 /* Print the list of candidate FNS in an error message. FNS can also
1959 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1961 void
1963 {
1967 }
1969 /* Get a (possibly) constrained template declaration for the
1970 purpose of ordering candidates. */
1971 static tree
1973 {
1979 }
1981 /* Among candidates having the same signature, return the
1982 most constrained or NULL_TREE if there is no best candidate.
1983 If the signatures of candidates vary (e.g., template
1984 specialization vs. member function), then there can be no
1985 most constrained.
1987 Note that we don't compare constraints on the functions
1988 themselves, but rather those of their templates. */
1989 static tree
1991 {
1992 // Try to find the best candidate in a first pass.
1995 {
2002 }
2004 // Verify that the champ is better than previous candidates.
2009 }
2012 }
2015 /* Returns the template (one of the functions given by TEMPLATE_ID)
2016 which can be specialized to match the indicated DECL with the
2017 explicit template args given in TEMPLATE_ID. The DECL may be
2018 NULL_TREE if none is available. In that case, the functions in
2019 TEMPLATE_ID are non-members.
2021 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2022 specialization of a member template.
2024 The TEMPLATE_COUNT is the number of references to qualifying
2025 template classes that appeared in the name of the function. See
2026 check_explicit_specialization for a more accurate description.
2028 TSK indicates what kind of template declaration (if any) is being
2029 declared. TSK_TEMPLATE indicates that the declaration given by
2030 DECL, though a FUNCTION_DECL, has template parameters, and is
2031 therefore a template function.
2033 The template args (those explicitly specified and those deduced)
2034 are output in a newly created vector *TARGS_OUT.
2036 If it is impossible to determine the result, an error message is
2037 issued. The error_mark_node is returned to indicate failure. */
2039 static tree
2041 tree decl,
2045 tmpl_spec_kind tsk)
2046 {
2047 tree fns;
2048 tree targs;
2049 tree explicit_targs;
2052 /* A TREE_LIST of templates of which DECL may be a specialization.
2053 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2054 corresponding TREE_PURPOSE is the set of template arguments that,
2055 when used to instantiate the template, would produce a function
2056 with the signature of DECL. */
2066 /* We shouldn't be specializing a member template of an
2067 unspecialized class template; we already gave an error in
2068 check_specialization_scope, now avoid crashing. */
2071 {
2074 }
2082 /* Check for baselinks. */
2087 {
2090 }
2092 {
2095 }
2097 /* Count the number of template headers specified for this
2098 specialization. */
2108 {
2111 tf_warning_or_error,
2115 }
2117 {
2121 {
2122 tree decl_arg_types;
2123 tree fn_arg_types;
2124 tree insttype;
2126 /* In case of explicit specialization, we need to check if
2127 the number of template headers appearing in the specialization
2128 is correct. This is usually done in check_explicit_specialization,
2129 but the check done there cannot be exhaustive when specializing
2130 member functions. Consider the following code:
2132 template <> void A<int>::f(int);
2133 template <> template <> void A<int>::f(int);
2135 Assuming that A<int> is not itself an explicit specialization
2136 already, the first line specializes "f" which is a non-template
2137 member function, whilst the second line specializes "f" which
2138 is a template member function. So both lines are syntactically
2139 correct, and check_explicit_specialization does not reject
2140 them.
2142 Here, we can do better, as we are matching the specialization
2143 against the declarations. We count the number of template
2144 headers, and we check if they match TEMPLATE_COUNT + 1
2145 (TEMPLATE_COUNT is the number of qualifying template classes,
2146 plus there must be another header for the member template
2147 itself).
2149 Notice that if header_count is zero, this is not a
2150 specialization but rather a template instantiation, so there
2151 is no check we can perform here. */
2155 /* Check that the number of template arguments at the
2156 innermost level for DECL is the same as for FN. */
2164 /* DECL might be a specialization of FN. */
2168 /* For a non-static member function, we need to make sure
2169 that the const qualification is the same. Since
2170 get_bindings does not try to merge the "this" parameter,
2171 we must do the comparison explicitly. */
2177 /* Skip the "this" parameter and, for constructors of
2178 classes with virtual bases, the VTT parameter. A
2179 full specialization of a constructor will have a VTT
2180 parameter, but a template never will. */
2181 decl_arg_types
2183 fn_arg_types
2186 /* Function templates cannot be specializations; there are
2187 no partial specializations of functions. Therefore, if
2188 the type of DECL does not match FN, there is no
2189 match.
2191 Note that it should never be the case that we have both
2192 candidates added here, and for regular member functions
2193 below. */
2195 {
2199 }
2201 /* See whether this function might be a specialization of this
2202 template. Suppress access control because we might be trying
2203 to make this specialization a friend, and we have already done
2204 access control for the declaration of the specialization. */
2210 /* We cannot deduce template arguments that when used to
2211 specialize TMPL will produce DECL. */
2214 /* Remove, from the set of candidates, all those functions
2215 whose constraints are not satisfied. */
2219 // Then, try to form the new function type.
2223 fn_arg_types
2228 /* Save this template, and the arguments deduced. */
2230 }
2232 /* FN is an ordinary member function, and we need a
2233 specialization of a member template. */
2234 ;
2236 /* We can get IDENTIFIER_NODEs here in certain erroneous
2237 cases. */
2238 ;
2240 /* This is just an ordinary non-member function. Nothing can
2241 be a specialization of that. */
2242 ;
2244 /* Cannot specialize functions that are created implicitly. */
2245 ;
2246 else
2247 {
2248 tree decl_arg_types;
2250 /* This is an ordinary member function. However, since
2251 we're here, we can assume its enclosing class is a
2252 template class. For example,
2254 template <typename T> struct S { void f(); };
2255 template <> void S<int>::f() {}
2257 Here, S<int>::f is a non-template, but S<int> is a
2258 template class. If FN has the same type as DECL, we
2259 might be in business. */
2262 /* Its enclosing class is an explicit specialization
2263 of a template class. This is not a candidate. */
2268 /* The return types differ. */
2271 /* Adjust the type of DECL in case FN is a static member. */
2278 decl_arg_types))
2281 // If the deduced arguments do not satisfy the constraints,
2282 // this is not a candidate.
2286 // Add the candidate.
2288 }
2289 }
2292 {
2293 /* We have:
2295 [temp.expl.spec]
2297 It is possible for a specialization with a given function
2298 signature to be instantiated from more than one function
2299 template. In such cases, explicit specification of the
2300 template arguments must be used to uniquely identify the
2301 function template specialization being specialized.
2303 Note that here, there's no suggestion that we're supposed to
2304 determine which of the candidate templates is most
2305 specialized. However, we, also have:
2307 [temp.func.order]
2309 Partial ordering of overloaded function template
2310 declarations is used in the following contexts to select
2311 the function template to which a function template
2312 specialization refers:
2314 -- when an explicit specialization refers to a function
2315 template.
2317 So, we do use the partial ordering rules, at least for now.
2318 This extension can only serve to make invalid programs valid,
2319 so it's safe. And, there is strong anecdotal evidence that
2320 the committee intended the partial ordering rules to apply;
2321 the EDG front end has that behavior, and John Spicer claims
2322 that the committee simply forgot to delete the wording in
2323 [temp.expl.spec]. */
2326 {
2329 }
2330 }
2332 // Concepts allows multiple declarations of member functions
2333 // with the same signature. Like above, we need to rely on
2334 // on the partial ordering of those candidates to determine which
2335 // is the best.
2337 {
2339 {
2342 }
2343 }
2346 {
2353 else
2356 }
2360 {
2366 }
2368 /* We have one, and exactly one, match. */
2370 {
2374 // Propagate the candidate's constraints to the declaration.
2377 /* DECL is a re-declaration or partial instantiation of a template
2378 function. */
2381 /* It was a specialization of an ordinary member function in a
2382 template class. */
2384 }
2386 /* It was a specialization of a template. */
2389 {
2394 }
2395 else
2398 }
2400 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2401 but with the default argument values filled in from those in the
2402 TMPL_TYPES. */
2404 static tree
2406 tree tmpl_types)
2407 {
2408 tree new_spec_types;
2416 /* Substitute into the rest of the list. */
2417 new_spec_types =
2421 /* Add the default argument for this parameter. */
2424 new_spec_types);
2425 }
2427 /* DECL is an explicit specialization. Replicate default arguments
2428 from the template it specializes. (That way, code like:
2430 template <class T> void f(T = 3);
2431 template <> void f(double);
2432 void g () { f (); }
2434 works, as required.) An alternative approach would be to look up
2435 the correct default arguments at the call-site, but this approach
2436 is consistent with how implicit instantiations are handled. */
2438 static void
2440 {
2441 tree tmpl;
2442 tree spec_types;
2443 tree tmpl_types;
2444 tree new_spec_types;
2445 tree old_type;
2446 tree new_type;
2447 tree t;
2452 /* See if there's anything we need to do. */
2465 {
2466 /* Remove the this pointer, but remember the object's type for
2467 CV quals. */
2473 {
2474 /* DECL may contain more parameters than TMPL due to the extra
2475 in-charge parameter in constructors and destructors. */
2478 }
2480 {
2483 }
2484 }
2486 /* Compute the merged default arguments. */
2487 new_spec_types =
2490 /* Compute the new FUNCTION_TYPE. */
2492 {
2496 new_spec_types);
2499 /* Put the in-charge parameter back. */
2502 new_spec_types);
2506 new_spec_types);
2507 }
2508 else
2510 new_spec_types);
2520 }
2522 /* Return the number of template headers we expect to see for a definition
2523 or specialization of CTYPE or one of its non-template members. */
2525 int
2527 {
2531 {
2532 /* You're supposed to have one `template <...>' for every
2533 template class, but you don't need one for a full
2534 specialization. For example:
2536 template <class T> struct S{};
2537 template <> struct S<int> { void f(); };
2538 void S<int>::f () {}
2540 is correct; there shouldn't be a `template <>' for the
2541 definition of `S<int>::f'. */
2543 /* If CTYPE does not have template information of any
2544 kind, then it is not a template, nor is it nested
2545 within a template. */
2553 }
2556 }
2558 /* Do a simple sanity check on the template headers that precede the
2559 variable declaration DECL. */
2561 void
2563 {
2568 {
2571 "variable templates only available with "
2574 // Namespace-scope variable templates should have a template header.
2576 }
2578 {
2585 "members of an explicitly specialized class are defined "
2587 }
2588 }
2590 /* An explicit specialization whose declarator-id or class-head-name is not
2591 qualified shall be declared in the nearest enclosing namespace of the
2592 template, or, if the namespace is inline (7.3.1), any namespace from its
2593 enclosing namespace set.
2595 If the name declared in the explicit instantiation is an unqualified name,
2596 the explicit instantiation shall appear in the namespace where its template
2597 is declared or, if that namespace is inline (7.3.1), any namespace from its
2598 enclosing namespace set. */
2600 void
2602 {
2607 {
2613 /* This was allowed in C++98, so only pedwarn. */
2615 "outside its namespace must use a nested-name-"
2617 }
2618 }
2620 /* Check to see if the function just declared, as indicated in
2621 DECLARATOR, and in DECL, is a specialization of a function
2622 template. We may also discover that the declaration is an explicit
2623 instantiation at this point.
2625 Returns DECL, or an equivalent declaration that should be used
2626 instead if all goes well. Issues an error message if something is
2627 amiss. Returns error_mark_node if the error is not easily
2628 recoverable.
2630 FLAGS is a bitmask consisting of the following flags:
2632 2: The function has a definition.
2633 4: The function is a friend.
2635 The TEMPLATE_COUNT is the number of references to qualifying
2636 template classes that appeared in the name of the function. For
2637 example, in
2639 template <class T> struct S { void f(); };
2640 void S<int>::f();
2642 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2643 classes are not counted in the TEMPLATE_COUNT, so that in
2645 template <class T> struct S {};
2646 template <> struct S<int> { void f(); }
2647 template <> void S<int>::f();
2649 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2650 invalid; there should be no template <>.)
2652 If the function is a specialization, it is marked as such via
2653 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2654 is set up correctly, and it is added to the list of specializations
2655 for that template. */
2657 tree
2659 tree decl,
2662 {
2671 tmpl_spec_kind tsk;
2674 {
2677 else
2679 }
2680 else
2684 {
2687 {
2690 }
2692 {
2694 /* This could be something like:
2696 template <class T> void f(T);
2697 class S { friend void f<>(int); } */
2699 else
2700 {
2701 /* This case handles bogus declarations like template <>
2702 template <class T> void f<int>(); */
2705 declarator);
2707 }
2708 }
2712 /* The error has already been reported in
2713 check_specialization_scope. */
2719 /* Fall through. */
2732 decl);
2735 else
2739 /* Fall through. */
2745 /* In cases like template<> constexpr bool v = true;
2746 We'll give an error in check_template_variable. */
2752 else
2758 {
2759 /* This case handles bogus declarations like template <>
2760 template <class T> void f<int>(); */
2764 declarator);
2766 {
2767 /* Partial specialization of variable template. */
2771 }
2775 else
2779 ok:;
2780 }
2783 /* This is a specialization of a member template, without
2784 specialization the containing class. Something like:
2786 template <class T> struct S {
2787 template <class U> void f (U);
2788 };
2789 template <> template <class U> void S<int>::f(U) {}
2791 That's a specialization -- but of the entire template. */
2797 }
2800 /* This doesn't apply to variable templates. */
2803 {
2807 {
2811 }
2812 }
2815 {
2820 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2822 {
2823 tree fns;
2828 else
2829 {
2830 /* If there is no class context, the explicit instantiation
2831 must be at namespace scope. */
2834 /* Find the namespace binding, using the declaration
2835 context. */
2839 /* If lookup fails, look for a friend declaration so we can
2840 give a better diagnostic. */
2846 {
2849 }
2850 }
2853 }
2859 {
2861 /* A specialization in class scope. This is invalid,
2862 but the error will already have been flagged by
2863 check_specialization_scope. */
2865 else
2866 {
2867 /* It's not valid to write an explicit instantiation in
2868 class scope, e.g.:
2870 class C { template void f(); }
2872 This case is caught by the parser. However, on
2873 something like:
2875 template class C { void f(); };
2877 (which is invalid) we can get here. The error will be
2878 issued later. */
2879 ;
2880 }
2883 }
2886 {
2887 // We'll match variable templates in start_decl.
2891 /* Find the list of functions in ctype that have the same
2892 name as the declared function. */
2898 {
2903 {
2904 /* From [temp.expl.spec]:
2906 If such an explicit specialization for the member
2907 of a class template names an implicitly-declared
2908 special member function (clause _special_), the
2909 program is ill-formed.
2911 Similar language is found in [temp.explicit]. */
2914 }
2917 }
2920 {
2924 }
2925 else
2926 {
2928 tree ovl;
2930 /* For a type-conversion operator, we cannot do a
2931 name-based lookup. We might be looking for `operator
2932 int' which will be a specialization of `operator T'.
2933 So, we find *all* the conversion operators, and then
2934 select from them. */
2942 {
2944 /* There are no more conversion functions. */
2947 /* Glue all these conversion functions together
2948 with those we already have. */
2951 }
2952 }
2955 {
2958 }
2959 else
2961 }
2963 /* Figure out what exactly is being specialized at this point.
2964 Note that for an explicit instantiation, even one for a
2965 member function, we cannot tell apriori whether the
2966 instantiation is for a member template, or just a member
2967 function of a template class. Even if a member template is
2968 being instantiated, the member template arguments may be
2969 elided if they can be deduced from the rest of the
2970 declaration. */
2973 member_specialization,
2974 template_count,
2975 tsk);
2978 /* We couldn't figure out what this declaration was
2979 specializing. */
2981 else
2982 {
2985 {
2987 "friend declaration %qD is not visible to "
2991 }
2999 {
3000 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3001 is done by do_decl_instantiation later. */
3007 {
3008 /* If TMPL is not the most general template (for
3009 example, if TMPL is a friend template that is
3010 injected into namespace scope), then there will
3011 be too many levels of TARGS. Remove some of them
3012 here. */
3014 tree new_targs;
3021 }
3024 }
3026 /* If we thought that the DECL was a member function, but it
3027 turns out to be specializing a static member function,
3028 make DECL a static member function as well. */
3034 /* If this is a specialization of a member template of a
3035 template class, we want to return the TEMPLATE_DECL, not
3036 the specialization of it. */
3038 {
3043 {
3044 tree parm;
3048 /* We want to use the argument list specified in the
3049 definition, not in the original declaration. */
3054 }
3057 }
3059 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3065 /* Inherit default function arguments from the template
3066 DECL is specializing. */
3070 /* This specialization has the same protection as the
3071 template it specializes. */
3075 /* 7.1.1-1 [dcl.stc]
3077 A storage-class-specifier shall not be specified in an
3078 explicit specialization...
3080 The parser rejects these, so unless action is taken here,
3081 explicit function specializations will always appear with
3082 global linkage.
3084 The action recommended by the C++ CWG in response to C++
3085 defect report 605 is to make the storage class and linkage
3086 of the explicit specialization match the templated function:
3088 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3089 */
3091 {
3095 /* A concept cannot be specialized. */
3097 {
3099 gen_tmpl);
3101 }
3103 /* This specialization has the same linkage and visibility as
3104 the function template it specializes. */
3107 {
3110 }
3113 {
3116 }
3117 }
3119 /* If DECL is a friend declaration, declared using an
3120 unqualified name, the namespace associated with DECL may
3121 have been set incorrectly. For example, in:
3123 template <typename T> void f(T);
3124 namespace N {
3125 struct S { friend void f<int>(int); }
3126 }
3128 we will have set the DECL_CONTEXT for the friend
3129 declaration to N, rather than to the global namespace. */
3134 /* This is not really a declaration of a specialization.
3135 It's just the name of an instantiation. But, it's not
3136 a request for an instantiation, either. */
3139 /* A specialization is not necessarily COMDAT. */
3145 /* If this is a full specialization, register it so that we can find
3146 it again. Partial specializations will be registered in
3147 process_partial_specialization. */
3152 /* A 'structor should already have clones. */
3158 }
3159 }
3162 }
3164 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3165 parameters. These are represented in the same format used for
3166 DECL_TEMPLATE_PARMS. */
3168 int
3170 {
3171 const_tree p1;
3172 const_tree p2;
3180 {
3192 {
3196 /* If either of the template parameters are invalid, assume
3197 they match for the sake of error recovery. */
3210 }
3211 }
3214 /* One set of parameters has more parameters lists than the
3215 other. */
3219 }
3221 /* Determine whether PARM is a parameter pack. */
3223 bool
3225 {
3226 /* Determine if we have a non-type template parameter pack. */
3233 /* If this is a list of template parameters, we could get a
3234 TYPE_DECL or a TEMPLATE_DECL. */
3238 /* Otherwise it must be a type template parameter. */
3242 }
3244 /* Determine if T is a function parameter pack. */
3246 bool
3248 {
3252 }
3254 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3255 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3257 tree
3259 {
3266 }
3268 /* Return true iff the function parameter PARAM_DECL was expanded
3269 from the function parameter pack PACK. */
3271 bool
3273 {
3278 /* The parameter pack and its pack arguments have the same
3279 DECL_PARM_INDEX. */
3281 }
3283 /* Determine whether ARGS describes a variadic template args list,
3284 i.e., one that is terminated by a template argument pack. */
3286 static bool
3288 {
3290 tree last_parm;
3304 }
3306 /* Generate a new name for the parameter pack name NAME (an
3307 IDENTIFIER_NODE) that incorporates its */
3309 static tree
3311 {
3312 /* Munge the name to include the parameter index. */
3313 #define NUMBUF_LEN 128
3327 }
3329 /* Return true if T is a primary function, class or alias template
3330 instantiation. */
3332 bool
3334 {
3348 }
3350 /* Return true if PARM is a template template parameter. */
3352 bool
3354 {
3356 }
3358 /* Return true iff PARM is a DECL representing a type template
3359 parameter. */
3361 bool
3363 {
3368 }
3370 /* Return the template parameters of T if T is a
3371 primary template instantiation, NULL otherwise. */
3373 tree
3375 {
3380 parms = INNERMOST_TEMPLATE_PARMS
3384 }
3386 /* Return the template parameters of the LEVELth level from the full list
3387 of template parameters PARMS. */
3389 tree
3391 {
3392 tree p;
3403 }
3405 /* Returns the template arguments of T if T is a template instantiation,
3406 NULL otherwise. */
3408 tree
3410 {
3418 }
3420 /* Return the argument pack elements of T if T is a template argument pack,
3421 NULL otherwise. */
3423 tree
3425 {
3431 }
3433 /* Structure used to track the progress of find_parameter_packs_r. */
3434 struct find_parameter_pack_data
3435 {
3436 /* TREE_LIST that will contain all of the parameter packs found by
3437 the traversal. */
3440 /* Set of AST nodes that have been visited by the traversal. */
3443 /* True iff we're making a type pack expansion. */
3445 };
3447 /* Identifies all of the argument packs that occur in a template
3448 argument and appends them to the TREE_LIST inside DATA, which is a
3449 find_parameter_pack_data structure. This is a subroutine of
3450 make_pack_expansion and uses_parameter_packs. */
3451 static tree
3453 {
3459 /* Handle type aliases/typedefs. */
3461 {
3468 }
3470 /* Identify whether this is a parameter pack or not. */
3472 {
3480 /* FALLTHRU */
3482 /* If the placeholder appears in the decl-specifier-seq of a function
3483 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3484 is a pack expansion, the invented template parameter is a template
3485 parameter pack. */
3495 {
3496 /* We don't want to walk into the type of a PARM_DECL,
3497 because we don't want to see the type parameter pack. */
3500 }
3503 /* Look through a lambda capture proxy to the field pack. */
3506 {
3512 }
3514 {
3516 find_parameter_packs_r,
3519 }
3526 /* Not a parameter pack. */
3528 }
3531 {
3532 /* Add this parameter pack to the list. */
3534 }
3540 /* This switch statement will return immediately if we don't find a
3541 parameter pack. */
3543 {
3548 /* Check the template itself. */
3551 /* Check the template arguments. */
3567 /* Fall through. */
3608 {
3609 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3610 type_pack_expansion_p to false so that any placeholders
3611 within the expression don't get marked as parameter packs. */
3619 }
3623 }
3626 }
3628 /* Determines if the expression or type T uses any parameter packs. */
3629 bool
3631 {
3640 }
3642 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3643 representation a base-class initializer into a parameter pack
3644 expansion. If all goes well, the resulting node will be an
3645 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3646 respectively. */
3647 tree
3649 {
3650 tree result;
3659 {
3660 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3661 class initializer. In this case, the TREE_PURPOSE will be a
3662 _TYPE node (representing the base class expansion we're
3663 initializing) and the TREE_VALUE will be a TREE_LIST
3664 containing the initialization arguments.
3666 The resulting expansion looks somewhat different from most
3667 expansions. Rather than returning just one _EXPANSION, we
3668 return a TREE_LIST whose TREE_PURPOSE is a
3669 TYPE_PACK_EXPANSION containing the bases that will be
3670 initialized. The TREE_VALUE will be identical to the
3671 original TREE_VALUE, which is a list of arguments that will
3672 be passed to each base. We do not introduce any new pack
3673 expansion nodes into the TREE_VALUE (although it is possible
3674 that some already exist), because the TREE_PURPOSE and
3675 TREE_VALUE all need to be expanded together with the same
3676 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3677 resulting TREE_PURPOSE will mention the parameter packs in
3678 both the bases and the arguments to the bases. */
3679 tree purpose;
3680 tree value;
3683 /* Determine which parameter packs will be used by the base
3684 class expansion. */
3693 {
3697 }
3700 {
3701 /* Collect the sets of parameter packs used in each of the
3702 initialization arguments. */
3704 {
3705 /* Determine which parameter packs will be expanded in this
3706 argument. */
3709 }
3710 }
3714 /* Create the pack expansion type for the base type. */
3719 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3720 they will rarely be compared to anything. */
3724 }
3729 /* Build the PACK_EXPANSION_* node. */
3730 result = for_types
3735 {
3736 /* Propagate type and const-expression information. */
3739 /* Mark this read now, since the expansion might be length 0. */
3741 }
3742 else
3743 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3744 they will rarely be compared to anything. */
3747 /* Determine which parameter packs will be expanded. */
3754 /* Make sure we found some parameter packs. */
3756 {
3759 else
3762 }
3768 }
3770 /* Checks T for any "bare" parameter packs, which have not yet been
3771 expanded, and issues an error if any are found. This operation can
3772 only be done on full expressions or types (e.g., an expression
3773 statement, "if" condition, etc.), because we could have expressions like:
3775 foo(f(g(h(args)))...)
3777 where "args" is a parameter pack. check_for_bare_parameter_packs
3778 should not be called for the subexpressions args, h(args),
3779 g(h(args)), or f(g(h(args))), because we would produce erroneous
3780 error messages.
3782 Returns TRUE and emits an error if there were bare parameter packs,
3783 returns FALSE otherwise. */
3784 bool
3786 {
3803 {
3807 {
3816 else
3821 else
3825 }
3828 }
3831 }
3833 /* Expand any parameter packs that occur in the template arguments in
3834 ARGS. */
3835 tree
3837 {
3843 /* First, determine if we need to expand anything, and the number of
3844 slots we'll need. */
3846 {
3851 {
3855 else
3857 }
3858 else
3859 {
3861 num_result_args++;
3862 }
3863 }
3865 /* If no expansion is necessary, we're done. */
3869 /* Expand arguments. */
3872 non_default_args_count =
3875 {
3878 {
3885 }
3886 else
3887 {
3890 }
3891 }
3895 }
3897 /* Checks if DECL shadows a template parameter.
3899 [temp.local]: A template-parameter shall not be redeclared within its
3900 scope (including nested scopes).
3902 Emits an error and returns TRUE if the DECL shadows a parameter,
3903 returns FALSE otherwise. */
3905 bool
3907 {
3908 tree olddecl;
3910 /* If we're not in a template, we can't possibly shadow a template
3911 parameter. */
3915 /* Figure out what we're shadowing. */
3920 /* If there's no previous binding for this name, we're not shadowing
3921 anything, let alone a template parameter. */
3925 /* If we're not shadowing a template parameter, we're done. Note
3926 that OLDDECL might be an OVERLOAD (or perhaps even an
3927 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3928 node. */
3932 /* We check for decl != olddecl to avoid bogus errors for using a
3933 name inside a class. We check TPFI to avoid duplicate errors for
3934 inline member templates. */
3940 /* Don't complain about the injected class name, as we've already
3941 complained about the class itself. */
3948 else
3953 }
3955 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3956 ORIG_LEVEL, DECL, and TYPE. */
3958 static tree
3962 tree decl,
3963 tree type)
3964 {
3975 }
3977 /* Find the canonical type parameter for the given template type
3978 parameter. Returns the canonical type parameter, which may be TYPE
3979 if no such parameter existed. */
3981 static tree
3983 {
3984 tree list;
3998 else
3999 {
4004 }
4005 }
4007 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4008 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4009 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4010 new one is created. */
4012 static tree
4014 tsubst_flags_t complain)
4015 {
4020 {
4039 /* Template template parameters need this. */
4041 {
4048 }
4049 }
4052 }
4054 /* Process information from new template parameter PARM and append it
4055 to the LIST being built. This new parameter is a non-type
4056 parameter iff IS_NON_TYPE is true. This new parameter is a
4057 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4058 is in PARM_LOC. */
4060 tree
4063 {
4072 {
4076 {
4080 else
4082 }
4085 }
4088 {
4094 {
4095 /* [temp.param]
4097 The top-level cv-qualifiers on the template-parameter are
4098 ignored when determining its type. */
4103 && !is_parameter_pack
4104 /* If we're in a nested template parameter list, the template
4105 template parameter could be a parameter pack. */
4107 {
4108 /* This template parameter is not a parameter pack, but it
4109 should be. Complain about "bare" parameter packs. */
4112 /* Recover by calling this a parameter pack. */
4114 }
4115 }
4117 /* A template parameter is not modifiable. */
4126 processing_template_decl,
4131 }
4132 else
4133 {
4134 tree t;
4138 {
4140 /* This is for distinguishing between real templates and template
4141 template parameters */
4145 }
4146 else
4147 {
4149 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4152 }
4159 processing_template_decl,
4163 }
4167 /* Build requirements for the type/template parameter.
4168 This must be done after SET_DECL_TEMPLATE_PARM_P or
4169 process_template_parm could fail. */
4174 /* Build the parameter node linking the parameter declaration,
4175 its default argument (if any), and its constraints (if any). */
4180 }
4182 /* The end of a template parameter list has been reached. Process the
4183 tree list into a parameter vector, converting each parameter into a more
4184 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4185 as PARM_DECLs. */
4187 tree
4189 {
4194 /* Pop the dummy parameter level and add the real one. */
4197 current_template_parms
4202 {
4206 }
4211 }
4213 // Explicitly indicate the end of the template parameter list. We assume
4214 // that the current template parameters have been constructed and/or
4215 // managed explicitly, as when creating new template template parameters
4216 // from a shorthand constraint.
4217 void
4219 {
4221 }
4223 /* end_template_decl is called after a template declaration is seen. */
4225 void
4227 {
4233 /* This matches the pushlevel in begin_template_parm_list. */
4238 }
4240 /* Takes a TREE_LIST representing a template parameter and convert it
4241 into an argument suitable to be passed to the type substitution
4242 functions. Note that If the TREE_LIST contains an error_mark
4243 node, the returned argument is error_mark_node. */
4245 tree
4247 {
4260 {
4264 {
4265 /* Turn this argument into a TYPE_ARGUMENT_PACK
4266 with a single element, which expands T. */
4275 }
4276 }
4277 else
4278 {
4282 {
4283 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4284 with a single element, which expands T. */
4296 }
4297 else
4299 }
4301 }
4303 /* Given a single level of template parameters (a TREE_VEC), return it
4304 as a set of template arguments. */
4306 static tree
4308 {
4318 }
4320 /* Given a set of template parameters, return them as a set of template
4321 arguments. The template parameters are represented as a TREE_VEC, in
4322 the form documented in cp-tree.h for template arguments. */
4324 static tree
4326 {
4327 tree header;
4332 /* If there is only one level of template parameters, we do not
4333 create a TREE_VEC of TREE_VECs. Instead, we return a single
4334 TREE_VEC containing the arguments. */
4339 {
4344 else
4346 }
4349 }
4351 /* Within the declaration of a template, return the currently active
4352 template parameters as an argument TREE_VEC. */
4354 static tree
4356 {
4358 }
4360 /* Update the declared TYPE by doing any lookups which were thought to be
4361 dependent, but are not now that we know the SCOPE of the declarator. */
4363 tree
4365 {
4376 /* Don't bother building up the args in this case. */
4378 {
4379 /* tsubst in the args corresponding to the template parameters,
4380 including auto if present. Most things will be unchanged, but
4381 make_typename_type and tsubst_qualified_id will resolve
4382 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4385 tree pushed;
4387 {
4391 }
4396 }
4402 {
4405 else
4407 }
4409 }
4411 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4412 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4413 the new template is a member template. */
4415 tree
4417 {
4425 }
4427 struct template_parm_data
4428 {
4429 /* The level of the template parameters we are currently
4430 processing. */
4433 /* The index of the specialization argument we are currently
4434 processing. */
4437 /* An array whose size is the number of template parameters. The
4438 elements are nonzero if the parameter has been used in any one
4439 of the arguments processed so far. */
4442 /* An array whose size is the number of template arguments. The
4443 elements are nonzero if the argument makes use of template
4444 parameters of this level. */
4446 };
4448 /* Subroutine of push_template_decl used to see if each template
4449 parameter in a partial specialization is used in the explicit
4450 argument list. If T is of the LEVEL given in DATA (which is
4451 treated as a template_parm_data*), then DATA->PARMS is marked
4452 appropriately. */
4454 static int
4456 {
4464 {
4467 }
4469 /* Return zero so that for_each_template_parm will continue the
4470 traversal of the tree; we want to mark *every* template parm. */
4472 }
4474 /* Process the partial specialization DECL. */
4476 static tree
4478 {
4485 tree inner_parms;
4486 tree inst;
4496 /* A concept cannot be specialized. */
4498 {
4501 }
4506 /* We check that each of the template parameters given in the
4507 partial specialization is used in the argument list to the
4508 specialization. For example:
4510 template <class T> struct S;
4511 template <class T> struct S<T*>;
4513 The second declaration is OK because `T*' uses the template
4514 parameter T, whereas
4516 template <class T> struct S<int>;
4518 is no good. Even trickier is:
4520 template <class T>
4521 struct S1
4522 {
4523 template <class U>
4524 struct S2;
4525 template <class U>
4526 struct S2<T>;
4527 };
4529 The S2<T> declaration is actually invalid; it is a
4530 full-specialization. Of course,
4532 template <class U>
4533 struct S2<T (*)(U)>;
4535 or some such would have been OK. */
4543 {
4548 NULL,
4550 }
4553 {
4554 /* One of the template parms was not used in a deduced context in the
4555 specialization. */
4557 {
4561 }
4565 }
4570 /* [temp.class.spec]
4572 The argument list of the specialization shall not be identical to
4573 the implicit argument list of the primary template. */
4574 tree main_args
4577 && (!flag_concepts
4580 {
4584 else
4588 }
4590 /* A partial specialization that replaces multiple parameters of the
4591 primary template with a pack expansion is less specialized for those
4592 parameters. */
4594 {
4596 "primary template because it replaces multiple parameters "
4600 }
4602 /* [temp.class.spec]
4604 A partially specialized non-type argument expression shall not
4605 involve template parameters of the partial specialization except
4606 when the argument expression is a simple identifier.
4608 The type of a template parameter corresponding to a specialized
4609 non-type argument shall not be dependent on a parameter of the
4610 specialization.
4612 Also, we verify that pack expansions only occur at the
4613 end of the argument list. */
4617 {
4624 {
4625 /* Extract the arguments from the argument pack. We'll be
4626 iterating over these in the following loop. */
4629 }
4632 {
4634 /* Get the Jth argument in the parameter pack. */
4638 {
4639 /* Pack expansions must come at the end of the
4640 argument list. */
4643 {
4647 else
4650 }
4651 }
4654 /* We only care about the pattern. */
4660 /* This next two lines are the `argument expression is not just a
4661 simple identifier' condition and also the `specialized
4662 non-type argument' bit. */
4666 {
4670 arg);
4671 else
4672 {
4673 /* Look at the corresponding template parameter,
4674 marking which template parameters its type depends
4675 upon. */
4679 {
4680 /* We haven't yet initialized TPD2. Do so now. */
4682 /* The number of parameters here is the number in the
4683 main template, which, as checked in the assertion
4684 above, is NARGS. */
4688 }
4690 /* Mark the template parameters. But this time, we're
4691 looking for the template parameters of the main
4692 template, not in the specialization. */
4699 NULL,
4703 {
4704 /* The type depended on some template parameters.
4705 If they are fully specialized in the
4706 specialization, that's OK. */
4715 "type %qT of template argument %qE depends "
4717 "type %qT of template argument %qE depends "
4719 type,
4720 arg);
4721 }
4722 }
4723 }
4724 }
4725 }
4727 /* We should only get here once. */
4731 // Build the template decl.
4741 /* We didn't register this in check_explicit_specialization so we could
4742 wait until the constraints were set. */
4744 else
4754 {
4760 {
4768 "declaration of %qD ambiguates earlier template "
4772 "partial specialization of %qD after instantiation "
4774 }
4775 }
4778 }
4780 /* PARM is a template parameter of some form; return the corresponding
4781 TEMPLATE_PARM_INDEX. */
4783 static tree
4785 {
4798 }
4800 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4801 parameter packs used by the template parameter PARM. */
4803 static void
4805 {
4806 /* A type parm can't refer to another parm. */
4810 {
4814 }
4821 }
4823 /* PARM is a template parameter pack. Return any parameter packs used in
4824 its type or the type of any of its template parameters. If there are
4825 any such packs, it will be instantiated into a fixed template parameter
4826 list by partial instantiation rather than be fully deduced. */
4828 tree
4830 {
4831 /* This can only be true in a member template. */
4834 /* This can only be true for a parameter pack. */
4837 /* A type parm can't refer to another parm. */
4851 }
4853 /* Check that a template declaration's use of default arguments and
4854 parameter packs is not invalid. Here, PARMS are the template
4855 parameters. IS_PRIMARY is true if DECL is the thing declared by
4856 a primary template. IS_PARTIAL is true if DECL is a partial
4857 specialization.
4859 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4860 declaration (but not a definition); 1 indicates a declaration, 2
4861 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4862 emitted for extraneous default arguments.
4864 Returns TRUE if there were no errors found, FALSE otherwise. */
4866 bool
4869 {
4872 tree parm_level;
4875 /* [temp.param]
4877 A default template-argument shall not be specified in a
4878 function template declaration or a function template definition, nor
4879 in the template-parameter-list of the definition of a member of a
4880 class template. */
4884 /* You can't have a function template declaration in a local
4885 scope, nor you can you define a member of a class template in a
4886 local scope. */
4894 /* A lambda doesn't have an explicit declaration; don't complain
4895 about the parms of the enclosing class. */
4902 /* If this is either a friend defined in the scope of the class
4903 or a member function. */
4909 /* And, if it was a member function, it really was defined in
4910 the scope of the class. */
4913 /* We already checked these parameters when the template was
4914 declared, so there's no need to do it again now. This function
4915 was defined in class scope, but we're processing its body now
4916 that the class is complete. */
4919 /* Core issue 226 (C++0x only): the following only applies to class
4920 templates. */
4923 {
4924 /* [temp.param]
4926 If a template-parameter has a default template-argument, all
4927 subsequent template-parameters shall have a default
4928 template-argument supplied. */
4930 {
4937 {
4947 {
4949 /* For better subsequent error-recovery, we indicate that
4950 there should have been a default argument. */
4953 }
4955 && !is_friend_decl
4956 /* Don't complain about an enclosing partial
4957 specialization. */
4962 /* A fixed parameter pack will be partially
4963 instantiated into a fixed length list. */
4965 {
4966 /* A primary class template can only have one
4967 parameter pack, at the end of the template
4968 parameter list. */
4976 }
4977 }
4978 }
4979 }
4982 || is_partial
4983 || !is_primary
4985 /* For an ordinary class template, default template arguments are
4986 allowed at the innermost level, e.g.:
4987 template <class T = int>
4988 struct S {};
4989 but, in a partial specialization, they're not allowed even
4990 there, as we have in [temp.class.spec]:
4992 The template parameter list of a specialization shall not
4993 contain default template argument values.
4995 So, for a partial specialization, or for a function template
4996 (in C++98/C++03), we look at all of them. */
4997 ;
4998 else
4999 /* But, for a primary class template that is not a partial
5000 specialization we look at all template parameters except the
5001 innermost ones. */
5004 /* Figure out what error message to issue. */
5019 else
5020 /* Per [temp.param]/9, "A default template-argument shall not be
5021 specified in the template-parameter-lists of the definition of
5022 a member of a class template that appears outside of the member's
5023 class.", thus if we aren't handling a member of a class template
5024 there is no need to examine the parameters. */
5028 /* If we're inside a class definition, there's no need to
5029 examine the parameters to the class itself. On the one
5030 hand, they will be checked when the class is defined, and,
5031 on the other, default arguments are valid in things like:
5032 template <class T = double>
5033 struct S { template <class U> void f(U); };
5034 Here the default argument for `S' has no bearing on the
5035 declaration of `f'. */
5037 else
5038 /* Check everything. */
5044 {
5051 {
5056 {
5058 {
5065 }
5067 /* Clear out the default argument so that we are not
5068 confused later. */
5070 }
5071 }
5073 /* At this point, if we're still interested in issuing messages,
5074 they must apply to classes surrounding the object declared. */
5078 }
5081 }
5083 /* Worker for push_template_decl_real, called via
5084 for_each_template_parm. DATA is really an int, indicating the
5085 level of the parameters we are interested in. If T is a template
5086 parameter of that level, return nonzero. */
5088 static int
5090 {
5096 else
5099 }
5101 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5102 DATA is really an int, indicating the innermost outer level of parameters.
5103 If T is a template parameter of that level or further out, return
5104 nonzero. */
5106 static int
5108 {
5114 else
5117 }
5119 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5120 parameters given by current_template_args, or reuses a
5121 previously existing one, if appropriate. Returns the DECL, or an
5122 equivalent one, if it is replaced via a call to duplicate_decls.
5124 If IS_FRIEND is true, DECL is a friend declaration. */
5126 tree
5128 {
5129 tree tmpl;
5130 tree args;
5131 tree info;
5132 tree ctx;
5136 /* True if the template is a member template, in the sense of
5137 [temp.mem]. */
5143 /* See if this is a partial specialization. */
5156 /* For a friend, we want the context of the friend function, not
5157 the type of which it is a friend. */
5161 /* In the case of a virtual function, we want the class in which
5162 it is defined. */
5164 else
5165 /* Otherwise, if we're currently defining some class, the DECL
5166 is assumed to be a member of the class. */
5175 /* See if this is a primary template. */
5178 /* A friend template that specifies a class context, i.e.
5179 template <typename T> friend void A<T>::f();
5180 is not primary. */
5185 else
5189 {
5196 {
5199 }
5201 {
5203 {
5206 }
5208 {
5209 /* [temp.mem]
5211 A destructor shall not be a member template. */
5214 }
5221 {
5222 /* [basic.stc.dynamic.allocation]
5224 An allocation function can be a function
5225 template. ... Template allocation functions shall
5226 have two or more parameters. */
5229 }
5230 }
5236 /* alias-declaration */
5240 else
5241 {
5244 }
5245 }
5247 /* Check to see that the rules regarding the use of default
5248 arguments are not being violated. */
5252 /* Ensure that there are no parameter packs in the type of this
5253 declaration that have not been expanded. */
5255 {
5256 /* Check each of the arguments individually to see if there are
5257 any bare parameter packs. */
5263 {
5266 {
5267 /* This is a PARM_DECL that contains unexpanded parameter
5268 packs. We have already complained about this in the
5269 check_for_bare_parameter_packs call, so just replace
5270 these types with ERROR_MARK_NODE. */
5273 }
5277 }
5279 /* Check for bare parameter packs in the return type and the
5280 exception specifiers. */
5282 /* Errors were already issued, set return type to int
5283 as the frontend doesn't expect error_mark_node as
5284 the return type. */
5288 }
5293 {
5296 }
5309 {
5314 /* If DECL is a TYPE_DECL for a class-template, then there won't
5315 be DECL_LANG_SPECIFIC. The information equivalent to
5316 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5320 {
5321 /* Since a template declaration already existed for this
5322 class-type, we must be redeclaring it here. Make sure
5323 that the redeclaration is valid. */
5325 current_template_parms,
5327 /* We don't need to create a new TEMPLATE_DECL; just use the
5328 one we already had. */
5330 }
5331 else
5332 {
5334 member_template_p);
5339 {
5340 /* A specialization of a member template of a template
5341 class. */
5345 }
5346 }
5347 }
5348 else
5349 {
5355 {
5358 }
5366 {
5367 tree new_tmpl;
5369 /* The declaration is a specialization of a member
5370 template, declared outside the class. Therefore, the
5371 innermost template arguments will be NULL, so we
5372 replace them with the arguments determined by the
5373 earlier call to check_explicit_specialization. */
5376 new_tmpl
5378 member_template_p);
5388 args,
5391 }
5393 /* Make sure the template headers we got make sense. */
5398 {
5403 }
5404 else
5406 {
5411 {
5415 else
5419 /* Avoid crash in import_export_decl. */
5422 }
5427 /* Can happen in erroneous input. */
5429 else
5431 }
5433 /* Check that the parms are used in the appropriate qualifying scopes
5434 in the declarator. */
5438 {
5444 /* Avoid crash in import_export_decl. */
5447 }
5448 }
5453 /* Push template declarations for global functions and types. Note
5454 that we do not try to push a global template friend declared in a
5455 template class; such a thing may well depend on the template
5456 parameters of the class. */
5459 {
5464 /* Hide template friend classes that haven't been declared yet. */
5466 {
5469 }
5470 }
5473 {
5479 {
5482 /* It is a conversion operator. See if the type converted to
5483 depends on innermost template operands. */
5486 depth))
5488 }
5490 /* Give template template parms a DECL_CONTEXT of the template
5491 for which they are a parameter. */
5494 {
5498 }
5504 }
5506 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5507 back to its most general template. If TMPL is a specialization,
5508 ARGS may only have the innermost set of arguments. Add the missing
5509 argument levels if necessary. */
5517 else
5518 {
5523 }
5526 && !is_friend
5529 /* Set DECL_COMDAT on template instantiations; if we force
5530 them to be emitted by explicit instantiation or -frepo,
5531 mark_needed will tell cgraph to do the right thing. */
5535 }
5537 tree
5539 {
5541 }
5543 /* FN is an inheriting constructor that inherits from the constructor
5544 template INHERITED; turn FN into a constructor template with a matching
5545 template header. */
5547 tree
5549 {
5550 tree inner_parms
5553 tree parms
5564 }
5566 /* Called when a class template TYPE is redeclared with the indicated
5567 template PARMS, e.g.:
5569 template <class T> struct S;
5570 template <class T> struct S {}; */
5572 bool
5574 {
5575 tree tmpl;
5576 tree tmpl_parms;
5580 {
5583 }
5587 /* The type is nested in some template class. Nothing to worry
5588 about here; there are no new template parameters for the nested
5589 type. */
5593 {
5595 tmpl);
5597 }
5603 {
5613 }
5616 {
5617 tree tmpl_parm;
5618 tree parm;
5619 tree tmpl_default;
5620 tree parm_default;
5634 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5635 TEMPLATE_DECL. */
5645 {
5649 }
5652 {
5653 /* We have in [temp.param]:
5655 A template-parameter may not be given default arguments
5656 by two different declarations in the same scope. */
5661 }
5664 /* Update the previous template parameters (which are the ones
5665 that will really count) with the new default value. */
5668 /* Update the new parameters, too; they'll be used as the
5669 parameters for any members. */
5672 /* Give each template template parm in this redeclaration a
5673 DECL_CONTEXT of the template for which they are a parameter. */
5675 {
5678 }
5679 }
5681 // Cannot redeclare a class template with a different set of constraints.
5683 {
5688 }
5691 }
5693 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5694 to be used when the caller has already checked
5695 (processing_template_decl
5696 && !instantiation_dependent_expression_p (expr)
5697 && potential_constant_expression (expr))
5698 and cleared processing_template_decl. */
5700 tree
5702 {
5705 complain,
5709 }
5711 /* Simplify EXPR if it is a non-dependent expression. Returns the
5712 (possibly simplified) expression. */
5714 tree
5716 {
5720 /* If we're in a template, but EXPR isn't value dependent, simplify
5721 it. We're supposed to treat:
5723 template <typename T> void f(T[1 + 1]);
5724 template <typename T> void f(T[2]);
5726 as two declarations of the same function, for example. */
5729 {
5730 processing_template_decl_sentinel s;
5732 }
5734 }
5736 tree
5738 {
5740 }
5742 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5743 an uninstantiated expression. */
5745 tree
5747 {
5751 {
5754 else
5755 {
5756 processing_template_decl_sentinel s;
5758 }
5759 }
5761 }
5763 /* True iff T is a specialization of a variable template. */
5765 bool
5767 {
5772 }
5774 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5775 template declaration, or a TYPE_DECL for an alias declaration. */
5777 bool
5779 {
5787 }
5789 /* Return TRUE iff T is a specialization of an alias template. */
5791 bool
5793 {
5794 /* It's an alias template specialization if it's an alias and its
5795 TYPE_NAME is a specialization of a primary template. */
5797 {
5801 {
5804 }
5805 }
5807 }
5809 /* An alias template is complex from a SFINAE perspective if a template-id
5810 using that alias can be ill-formed when the expansion is not, as with
5811 the void_t template. We determine this by checking whether the
5812 expansion for the alias template uses all its template parameters. */
5814 struct uses_all_template_parms_data
5815 {
5818 };
5820 static int
5822 {
5830 }
5832 static bool
5834 {
5849 }
5851 /* Return TRUE iff T is a specialization of a complex alias template with
5852 dependent template-arguments. */
5854 bool
5856 {
5859 && (any_dependent_template_arguments_p
5861 }
5863 /* Return the number of innermost template parameters in TMPL. */
5865 static int
5867 {
5870 }
5872 /* Return either TMPL or another template that it is equivalent to under DR
5873 1286: An alias that just changes the name of a template is equivalent to
5874 the other template. */
5876 static tree
5878 {
5881 {
5884 {
5889 {
5890 tree alias_args = INNERMOST_TEMPLATE_ARGS
5894 /* The alias type is equivalent to the pattern of the
5895 underlying template, so strip the alias. */
5898 }
5899 }
5901 }
5903 }
5905 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5906 must be a reference-to-function or a pointer-to-function type, as specified
5907 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5908 and check that the resulting function has external linkage. */
5910 static tree
5912 tsubst_flags_t complain)
5913 {
5916 linkage_kind linkage;
5928 /* [temp.arg.nontype]/1
5930 A template-argument for a non-type, non-template template-parameter
5931 shall be one of:
5932 [...]
5933 -- the address of an object or function with external [C++11: or
5934 internal] linkage. */
5937 {
5939 {
5945 else
5948 }
5950 }
5954 {
5956 {
5961 else
5965 }
5967 }
5975 }
5977 /* Subroutine of convert_nontype_argument.
5978 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5979 Emit an error otherwise. */
5981 static bool
5983 tsubst_flags_t complain)
5984 {
5995 {
5999 }
6001 }
6003 /* Returns TRUE iff the address of OP is value-dependent.
6005 14.6.2.4 [temp.dep.temp]:
6006 A non-integral non-type template-argument is dependent if its type is
6007 dependent or it has either of the following forms
6008 qualified-id
6009 & qualified-id
6010 and contains a nested-name-specifier which specifies a class-name that
6011 names a dependent type.
6013 We generalize this to just say that the address of a member of a
6014 dependent class is value-dependent; the above doesn't cover the
6015 address of a static data member named with an unqualified-id. */
6017 static bool
6019 {
6020 /* We could use get_inner_reference here, but there's no need;
6021 this is only relevant for template non-type arguments, which
6022 can only be expressed as &id-expression. */
6024 {
6028 }
6031 }
6033 /* The next set of functions are used for providing helpful explanatory
6034 diagnostics for failed overload resolution. Their messages should be
6035 indented by two spaces for consistency with the messages in
6036 call.c */
6038 static int
6040 {
6042 }
6044 static int
6046 {
6051 }
6053 static int
6055 {
6057 }
6059 static int
6061 {
6067 }
6069 static int
6071 {
6075 }
6077 static int
6079 {
6082 " template parameter %qD is not a parameter pack, but "
6086 }
6088 static int
6090 {
6093 " template argument %qE does not match "
6097 }
6099 static int
6101 {
6105 }
6107 static int
6109 {
6115 }
6117 static int
6119 {
6121 {
6126 else
6128 " deduced conflicting values for non-type parameter "
6130 }
6132 }
6134 static int
6136 {
6139 " variable-sized array type %qT is not "
6141 arg);
6143 }
6145 static int
6147 {
6151 arg);
6153 }
6155 static int
6157 {
6159 {
6165 else
6170 }
6172 }
6174 static int
6176 {
6178 }
6180 static int
6183 {
6185 }
6187 static int
6190 {
6196 }
6198 static int
6201 {
6204 {
6212 }
6214 }
6216 static int
6218 {
6221 " template parameters of a template template argument are "
6224 }
6226 static int
6228 {
6234 }
6236 static int
6238 {
6243 }
6245 static int
6247 {
6251 arg);
6253 }
6255 /* Attempt to convert the non-type template parameter EXPR to the
6256 indicated TYPE. If the conversion is successful, return the
6257 converted value. If the conversion is unsuccessful, return
6258 NULL_TREE if we issued an error message, or error_mark_node if we
6259 did not. We issue error messages for out-and-out bad template
6260 parameters, but not simply because the conversion failed, since we
6261 might be just trying to do argument deduction. Both TYPE and EXPR
6262 must be non-dependent.
6264 The conversion follows the special rules described in
6265 [temp.arg.nontype], and it is much more strict than an implicit
6266 conversion.
6268 This function is called twice for each template argument (see
6269 lookup_template_class for a more accurate description of this
6270 problem). This means that we need to handle expressions which
6271 are not valid in a C++ source, but can be created from the
6272 first call (for instance, casts to perform conversions). These
6273 hacks can go away after we fix the double coercion problem. */
6275 static tree
6277 {
6278 tree expr_type;
6280 /* Detect immediately string literals as invalid non-type argument.
6281 This special-case is not needed for correctness (we would easily
6282 catch this later), but only to provide better diagnostic for this
6283 common user mistake. As suggested by DR 100, we do not mention
6284 linkage issues in the diagnostic as this is not the point. */
6285 /* FIXME we're making this OK. */
6287 {
6293 }
6295 /* Add the ADDR_EXPR now for the benefit of
6296 value_dependent_expression_p. */
6299 {
6303 }
6305 /* If we are in a template, EXPR may be non-dependent, but still
6306 have a syntactic, rather than semantic, form. For example, EXPR
6307 might be a SCOPE_REF, rather than the VAR_DECL to which the
6308 SCOPE_REF refers. Preserving the qualifying scope is necessary
6309 so that access checking can be performed when the template is
6310 instantiated -- but here we need the resolved form so that we can
6311 convert the argument. */
6324 else
6327 /* If the argument is non-dependent, perform any conversions in
6328 non-dependent context as well. */
6336 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6337 to a non-type argument of "nullptr". */
6341 /* In C++11, integral or enumeration non-type template arguments can be
6342 arbitrary constant expressions. Pointer and pointer to
6343 member arguments can be general constant expressions that evaluate
6344 to a null value, but otherwise still need to be of a specific form. */
6346 {
6348 /* A PTRMEM_CST is already constant, and a valid template
6349 argument for a parameter of pointer to member type, we just want
6350 to leave it in that form rather than lower it to a
6355 {
6359 {
6363 }
6364 }
6366 {
6371 }
6372 }
6374 /* HACK: Due to double coercion, we can get a
6375 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6376 which is the tree that we built on the first call (see
6377 below when coercing to reference to object or to reference to
6378 function). We just strip everything and get to the arg.
6379 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6380 for examples. */
6382 {
6388 {
6389 /* ??? Maybe we could use convert_from_reference here, but we
6390 would need to relax its constraints because the NOP_EXPR
6391 could actually change the type to something more cv-qualified,
6392 and this is not folded by convert_from_reference. */
6397 && (same_type_ignoring_top_level_qualifiers_p
6400 {
6403 }
6404 }
6405 }
6407 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6408 parameter is a pointer to object, through decay and
6409 qualification conversion. Let's strip everything. */
6411 {
6416 {
6417 /* Skip the ADDR_EXPR only if it is part of the decay for
6418 an array. Otherwise, it is part of the original argument
6419 in the source code. */
6424 }
6425 }
6427 /* [temp.arg.nontype]/5, bullet 1
6429 For a non-type template-parameter of integral or enumeration type,
6430 integral promotions (_conv.prom_) and integral conversions
6431 (_conv.integral_) are applied. */
6433 {
6442 /* Notice that there are constant expressions like '4 % 0' which
6443 do not fold into integer constants. */
6446 {
6448 {
6459 /* else cxx_constant_value complained but gave us
6460 a real constant, so go ahead. */
6462 }
6463 else
6465 }
6467 /* Avoid typedef problems. */
6470 }
6471 /* [temp.arg.nontype]/5, bullet 2
6473 For a non-type template-parameter of type pointer to object,
6474 qualification conversions (_conv.qual_) and the array-to-pointer
6475 conversion (_conv.array_) are applied. */
6477 {
6478 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6480 A template-argument for a non-type, non-template template-parameter
6481 shall be one of: [...]
6483 -- the name of a non-type template-parameter;
6484 -- the address of an object or function with external linkage, [...]
6485 expressed as "& id-expression" where the & is optional if the name
6486 refers to a function or array, or if the corresponding
6487 template-parameter is a reference.
6489 Here, we do not care about functions, as they are invalid anyway
6490 for a parameter of type pointer-to-object. */
6493 /* Non-type template parameters are OK. */
6494 ;
6499 {
6501 {
6504 "because %qD is a variable, not the address of "
6507 }
6509 {
6515 }
6516 /* Other values, like integer constants, might be valid
6517 non-type arguments of some other type. */
6519 }
6520 else
6521 {
6522 tree decl;
6527 {
6532 }
6534 {
6540 }
6542 {
6547 }
6548 }
6557 }
6558 /* [temp.arg.nontype]/5, bullet 3
6560 For a non-type template-parameter of type reference to object, no
6561 conversions apply. The type referred to by the reference may be more
6562 cv-qualified than the (otherwise identical) type of the
6563 template-argument. The template-parameter is bound directly to the
6564 template-argument, which must be an lvalue. */
6566 {
6568 expr_type))
6572 {
6577 }
6580 {
6585 }
6587 /* [temp.arg.nontype]/1
6589 A template-argument for a non-type, non-template template-parameter
6590 shall be one of: [...]
6592 -- the address of an object or function with external linkage. */
6595 {
6598 {
6601 "because a reference variable does not have a constant "
6604 }
6605 }
6608 {
6610 {
6616 }
6618 /* DR 1155 allows internal linkage in C++11 and up. */
6621 {
6627 }
6630 }
6631 }
6632 /* [temp.arg.nontype]/5, bullet 4
6634 For a non-type template-parameter of type pointer to function, only
6635 the function-to-pointer conversion (_conv.func_) is applied. If the
6636 template-argument represents a set of overloaded functions (or a
6637 pointer to such), the matching function is selected from the set
6638 (_over.over_). */
6640 {
6641 /* If the argument is a template-id, we might not have enough
6642 context information to decay the pointer. */
6644 {
6648 }
6651 /* Null pointer values are OK in C++11. */
6658 }
6659 /* [temp.arg.nontype]/5, bullet 5
6661 For a non-type template-parameter of type reference to function, no
6662 conversions apply. If the template-argument represents a set of
6663 overloaded functions, the matching function is selected from the set
6664 (_over.over_). */
6666 {
6668 {
6670 {
6675 }
6677 }
6683 }
6684 /* [temp.arg.nontype]/5, bullet 6
6686 For a non-type template-parameter of type pointer to member function,
6687 no conversions apply. If the template-argument represents a set of
6688 overloaded member functions, the matching member function is selected
6689 from the set (_over.over_). */
6691 {
6696 /* [temp.arg.nontype] bullet 1 says the pointer to member
6697 expression must be a pointer-to-member constant. */
6702 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6703 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6707 /* There is no way to disable standard conversions in
6708 resolve_address_of_overloaded_function (called by
6709 instantiate_type). It is possible that the call succeeded by
6710 converting &B::I to &D::I (where B is a base of D), so we need
6711 to reject this conversion here.
6713 Actually, even if there was a way to disable standard conversions,
6714 it would still be better to reject them here so that we can
6715 provide a superior diagnostic. */
6717 {
6719 {
6723 /* If we are just one standard conversion off, explain. */
6727 }
6729 }
6730 }
6731 /* [temp.arg.nontype]/5, bullet 7
6733 For a non-type template-parameter of type pointer to data member,
6734 qualification conversions (_conv.qual_) are applied. */
6736 {
6737 /* [temp.arg.nontype] bullet 1 says the pointer to member
6738 expression must be a pointer-to-member constant. */
6746 }
6748 {
6750 {
6755 }
6757 }
6758 /* A template non-type parameter must be one of the above. */
6759 else
6762 /* Sanity check: did we actually convert the argument to the
6763 right type? */
6767 }
6769 /* Subroutine of coerce_template_template_parms, which returns 1 if
6770 PARM_PARM and ARG_PARM match using the rule for the template
6771 parameters of template template parameters. Both PARM and ARG are
6772 template parameters; the rest of the arguments are the same as for
6773 coerce_template_template_parms.
6774 */
6775 static int
6777 tree arg,
6778 tsubst_flags_t complain,
6779 tree in_decl,
6780 tree outer_args)
6781 {
6790 {
6792 /* We encounter instantiations of templates like
6793 template <template <template <class> class> class TT>
6794 class C; */
6795 {
6802 }
6803 /* Fall through. */
6808 /* Argument is a parameter pack but parameter is not. */
6813 /* The tsubst call is used to handle cases such as
6815 template <int> class C {};
6816 template <class T, template <T> class TT> class D {};
6817 D<int, C> d;
6819 i.e. the parameter list of TT depends on earlier parameters. */
6821 {
6826 }
6830 /* Argument is a parameter pack but parameter is not. */
6837 }
6840 }
6843 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6844 template template parameters. Both PARM_PARMS and ARG_PARMS are
6845 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6846 or PARM_DECL.
6848 Consider the example:
6849 template <class T> class A;
6850 template<template <class U> class TT> class B;
6852 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6853 the parameters to A, and OUTER_ARGS contains A. */
6855 static int
6857 tree arg_parms,
6858 tsubst_flags_t complain,
6859 tree in_decl,
6860 tree outer_args)
6861 {
6872 /* Determine whether we have a parameter pack at the end of the
6873 template template parameter's template parameter list. */
6875 {
6882 {
6896 }
6897 }
6903 /* Check all of the template parameters except the parameter pack at
6904 the end (if any). */
6906 {
6915 outer_args))
6918 }
6921 {
6922 /* Check each of the template parameters in the template
6923 argument against the template parameter pack at the end of
6924 the template template parameter. */
6931 {
6938 outer_args))
6940 }
6941 }
6944 }
6946 /* Verifies that the deduced template arguments (in TARGS) for the
6947 template template parameters (in TPARMS) represent valid bindings,
6948 by comparing the template parameter list of each template argument
6949 to the template parameter list of its corresponding template
6950 template parameter, in accordance with DR150. This
6951 routine can only be called after all template arguments have been
6952 deduced. It will return TRUE if all of the template template
6953 parameter bindings are okay, FALSE otherwise. */
6954 bool
6956 {
6960 /* We're dealing with template parms in this process. */
6966 {
6971 {
6976 {
6977 /* Look inside the argument pack. */
6980 }
6983 {
6987 /* Extract the next argument from the argument
6988 pack. */
6992 /* Look at the pattern of the pack expansion. */
6995 /* Extract the template parameters from the template
6996 argument. */
7002 /* Verify that we can coerce the template template
7003 parameters from the template argument to the template
7004 parameter. This requires an exact match. */
7006 && !coerce_template_template_parms
7008 targ_parms,
7009 tf_none,
7010 tparm,
7011 targs))
7012 {
7015 }
7016 }
7017 }
7018 }
7020 out:
7024 }
7026 /* Since type attributes aren't mangled, we need to strip them from
7027 template type arguments. */
7029 static tree
7031 {
7041 }
7043 /* And from inside dependent non-type arguments like sizeof(Type). */
7045 static tree
7047 {
7057 }
7059 // A template declaration can be substituted for a constrained
7060 // template template parameter only when the argument is more
7061 // constrained than the parameter.
7062 static bool
7064 {
7067 /* For now, allow constrained template template arguments
7068 and unconstrained template template parameters. */
7074 // If the template parameter is constrained, we need to rewrite its
7075 // constraints in terms of the ARG's template parameters. This ensures
7076 // that all of the template parameter types will have the same depth.
7077 //
7078 // Note that this is only valid when coerce_template_template_parm is
7079 // true for the innermost template parameters of PARM and ARG. In other
7080 // words, because coercion is successful, this conversion will be valid.
7082 {
7089 }
7092 }
7094 // Convert a placeholder argument into a binding to the original
7095 // parameter. The original parameter is saved as the TREE_TYPE of
7096 // ARG.
7099 {
7102 }
7104 /* Convert the indicated template ARG as necessary to match the
7105 indicated template PARM. Returns the converted ARG, or
7106 error_mark_node if the conversion was unsuccessful. Error and
7107 warning messages are issued under control of COMPLAIN. This
7108 conversion is for the Ith parameter in the parameter list. ARGS is
7109 the full set of template arguments deduced so far. */
7111 static tree
7113 tree arg,
7114 tree args,
7115 tsubst_flags_t complain,
7117 tree in_decl)
7118 {
7119 tree orig_arg;
7120 tree val;
7126 /* Trivially convert placeholders. */
7132 {
7133 /* The template argument was the name of some
7134 member function. That's usually
7135 invalid, but static members are OK. In any
7136 case, grab the underlying fields/functions
7137 and issue an error later if required. */
7140 }
7148 /* When determining whether an argument pack expansion is a template,
7149 look at the pattern. */
7153 /* Deal with an injected-class-name used as a template template arg. */
7155 {
7158 {
7168 }
7169 }
7171 is_tmpl_type =
7187 {
7189 {
7193 }
7196 "to refer to a type member of a template parameter, "
7201 typename_type,
7202 complain);
7205 }
7207 {
7209 {
7211 {
7223 else
7226 }
7227 }
7229 }
7231 {
7233 {
7240 else
7243 }
7245 }
7248 {
7250 {
7254 /* The number of argument required is not known yet.
7255 Just accept it for now. */
7257 else
7258 {
7260 tree argparm;
7262 /* Strip alias templates that are equivalent to another
7263 template. */
7269 args))
7270 {
7273 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7274 TEMPLATE_DECL. */
7276 {
7281 }
7282 }
7283 else
7284 {
7286 {
7293 }
7296 }
7298 // Check that the constraints are compatible before allowing the
7299 // substitution.
7302 {
7304 {
7310 }
7312 }
7313 }
7314 }
7315 else
7317 /* We only form one instance of each template specialization.
7318 Therefore, if we use a non-canonical variant (i.e., a
7319 typedef), any future messages referring to the type will use
7320 the typedef, which is confusing if those future uses do not
7321 themselves also use the typedef. */
7324 }
7325 else
7326 {
7330 {
7334 }
7340 {
7343 else
7344 {
7345 /* Not sure if this is reachable, but it doesn't hurt
7346 to be robust. */
7349 }
7350 }
7353 /* We used to call digest_init here. However, digest_init
7354 will report errors, which we don't want when complain
7355 is zero. More importantly, digest_init will try too
7356 hard to convert things: for example, `0' should not be
7357 converted to pointer type at this point according to
7358 the standard. Accepting this is not merely an
7359 extension, since deciding whether or not these
7360 conversions can occur is part of determining which
7361 function template to call, or whether a given explicit
7362 argument specification is valid. */
7364 else
7374 {
7375 /* Reject template arguments that are references to built-in
7376 functions with no library fallbacks. */
7384 }
7387 {
7388 /* Strip typedefs from the SCOPE_REF. */
7391 complain);
7394 }
7395 }
7398 }
7400 /* Coerces the remaining template arguments in INNER_ARGS (from
7401 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7402 Returns the coerced argument pack. PARM_IDX is the position of this
7403 parameter in the template parameter list. ARGS is the original
7404 template argument list. */
7405 static tree
7408 tree args,
7409 tree inner_args,
7411 tree new_args,
7413 tree in_decl,
7414 tsubst_flags_t complain)
7415 {
7418 tree packed_args;
7419 tree argument_pack;
7426 {
7427 /* When the template parameter is a non-type template parameter pack
7428 or template template parameter pack whose type or template
7429 parameters use parameter packs, we know exactly how many arguments
7430 we are looking for. Build a vector of the instantiated decls for
7431 these template parameters in PACKED_PARMS. */
7432 /* We can't use make_pack_expansion here because it would interpret a
7433 _DECL as a use rather than a declaration. */
7447 /* If we're doing a partial instantiation of a member template,
7448 verify that all of the types used for the non-type
7449 template parameter pack are, in fact, valid for non-type
7450 template parameters. */
7453 {
7456 {
7460 }
7461 /* We don't know how many args we have yet, just
7462 use the unconverted ones for now. */
7464 }
7467 }
7468 /* Check if we have a placeholder pack, which indicates we're
7469 in the context of a introduction list. In that case we want
7470 to match this pack to the single placeholder. */
7474 {
7477 }
7478 else
7481 /* Convert the remaining arguments, which will be a part of the
7482 parameter pack "parm". */
7485 {
7491 {
7492 /* Once we've packed as many args as we have types, stop. */
7496 /* We don't know how many args we have yet, just
7497 use the unconverted ones for now. */
7499 else
7501 }
7504 {
7507 }
7508 else
7511 in_decl);
7515 }
7519 {
7524 }
7529 else
7530 {
7535 }
7542 }
7544 /* Returns the number of pack expansions in the template argument vector
7545 ARGS. */
7547 static int
7549 {
7554 {
7558 }
7560 }
7562 /* Convert all template arguments to their appropriate types, and
7563 return a vector containing the innermost resulting template
7564 arguments. If any error occurs, return error_mark_node. Error and
7565 warning messages are issued under control of COMPLAIN.
7567 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7568 for arguments not specified in ARGS. Otherwise, if
7569 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7570 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7571 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7572 ARGS. */
7574 static tree
7576 tree args,
7577 tree in_decl,
7578 tsubst_flags_t complain,
7581 {
7583 tree orig_inner_args;
7584 tree inner_args;
7585 tree new_args;
7586 tree new_inner_args;
7590 /* When used as a boolean value, indicates whether this is a
7591 variadic template parameter list. Since it's an int, we can also
7592 subtract it from nparms to get the number of non-variadic
7593 parameters. */
7598 /* Likewise for parameters with default arguments. */
7606 /* Determine if there are any parameter packs or default arguments. */
7608 {
7616 }
7619 /* If there are no parameters that follow a parameter pack, we need to
7620 expand any argument packs so that we can deduce a parameter pack from
7621 some non-packed args followed by an argument pack, as in variadic85.C.
7622 If there are such parameters, we need to leave argument packs intact
7623 so the arguments are assigned properly. This can happen when dealing
7624 with a nested class inside a partial specialization of a class
7625 template, as in variadic92.C, or when deducing a template parameter pack
7626 from a sub-declarator, as in variadic114.C. */
7630 /* Count any pack expansion args. */
7636 && require_all_args
7637 && !variadic_args_p
7638 && (!use_default_args
7641 {
7643 {
7645 {
7649 }
7650 else
7657 }
7660 }
7661 /* We can't pass a pack expansion to a non-pack parameter of an alias
7662 template (DR 1430). */
7666 && variadic_args_p
7668 {
7670 {
7672 {
7678 {
7681 "pack expansion argument for non-pack parameter "
7683 else
7685 "pack expansion argument for non-pack parameter "
7689 }
7690 }
7692 found:;
7693 }
7695 }
7697 /* We need to evaluate the template arguments, even though this
7698 template-id may be nested within a "sizeof". */
7707 {
7708 tree arg;
7709 tree parm;
7711 /* Get the Ith template parameter. */
7715 {
7718 }
7720 /* Calculate the next argument. */
7723 else
7728 {
7729 /* Some arguments will be placed in the
7730 template parameter pack PARM. */
7737 {
7738 /* We don't know how many args we have yet, just use the
7739 unconverted (and still packed) ones for now. */
7743 }
7747 /* Store this argument. */
7749 {
7750 lost++;
7751 /* We are done with all of the arguments. */
7753 }
7754 else
7755 {
7758 }
7761 }
7763 {
7765 {
7766 /* "If every valid specialization of a variadic template
7767 requires an empty template parameter pack, the template is
7768 ill-formed, no diagnostic required." So check that the
7769 pattern works with this parameter. */
7774 in_decl);
7776 {
7780 }
7782 /* Recover from missing typename. */
7786 /* We don't know how many args we have yet, just
7787 use the unconverted ones for now. */
7791 }
7792 }
7794 {
7795 /* There must be a default arg in this case. */
7798 /* The position of the first default template argument,
7799 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7800 Record that. */
7804 }
7805 else
7809 {
7812 }
7814 /* This only occurs if there was an error in the template
7815 parameter list itself (which we would already have
7816 reported) that we are trying to recover from, e.g., a class
7817 template with a parameter list such as
7818 template<typename..., typename>. */
7820 else
7826 lost++;
7828 }
7833 {
7835 {
7840 }
7842 }
7852 }
7854 /* Convert all template arguments to their appropriate types, and
7855 return a vector containing the innermost resulting template
7856 arguments. If any error occurs, return error_mark_node. Error and
7857 warning messages are not issued.
7859 Note that no function argument deduction is performed, and default
7860 arguments are used to fill in unspecified arguments. */
7861 tree
7863 {
7865 }
7867 /* Convert all template arguments to their appropriate type, and
7868 instantiate default arguments as needed. This returns a vector
7869 containing the innermost resulting template arguments, or
7870 error_mark_node if unsuccessful. */
7871 tree
7873 tsubst_flags_t complain)
7874 {
7876 }
7878 /* Like coerce_template_parms. If PARMS represents all template
7879 parameters levels, this function returns a vector of vectors
7880 representing all the resulting argument levels. Note that in this
7881 case, only the innermost arguments are coerced because the
7882 outermost ones are supposed to have been coerced already.
7884 Otherwise, if PARMS represents only (the innermost) vector of
7885 parameters, this function returns a vector containing just the
7886 innermost resulting arguments. */
7888 static tree
7890 tree args,
7891 tree in_decl,
7892 tsubst_flags_t complain,
7895 {
7898 tree coerced_args;
7901 {
7903 tree level;
7909 {
7910 tree l;
7914 require_all_args,
7915 use_default_args);
7916 else
7923 }
7924 }
7925 else
7928 require_all_args,
7929 use_default_args);
7931 }
7933 /* Returns 1 if template args OT and NT are equivalent. */
7935 int
7937 {
7944 /* For member templates */
7953 {
7970 }
7974 {
7977 /* Don't treat an alias template specialization with dependent
7978 arguments as equivalent to its underlying type when used as a
7979 template argument; we need them to be distinct so that we
7980 substitute into the specialization arguments at instantiation
7981 time. And aliases can't be equivalent without being ==, so
7982 we don't need to look any deeper. */
7985 else
7987 }
7990 else
7991 {
7992 /* Try to treat a template non-type argument that has been converted
7993 to the parameter type as equivalent to one that hasn't yet. */
8006 }
8007 }
8009 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8010 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8011 NEWARG_PTR with the offending arguments if they are non-NULL. */
8013 int
8016 {
8029 {
8034 {
8040 }
8041 }
8043 }
8045 static void
8047 {
8057 /* We are called both from instantiate_decl, where we've already had a
8058 tinst_level pushed, and instantiate_template, where we haven't.
8059 Compensate. */
8070 else
8079 }
8082 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8083 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8084 documentation for TEMPLATE_ID_EXPR. */
8086 tree
8088 {
8089 tree type;
8097 {
8100 }
8103 {
8105 unknown_type_node,
8107 arglist);
8109 }
8116 }
8118 /* Within the scope of a template class S<T>, the name S gets bound
8119 (in build_self_reference) to a TYPE_DECL for the class, not a
8120 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8121 or one of its enclosing classes, and that type is a template,
8122 return the associated TEMPLATE_DECL. Otherwise, the original
8123 DECL is returned.
8125 Also handle the case when DECL is a TREE_LIST of ambiguous
8126 injected-class-names from different bases. */
8128 tree
8130 {
8134 /* DR 176: A lookup that finds an injected-class-name (10.2
8135 [class.member.lookup]) can result in an ambiguity in certain cases
8136 (for example, if it is found in more than one base class). If all of
8137 the injected-class-names that are found refer to specializations of
8138 the same class template, and if the name is followed by a
8139 template-argument-list, the reference refers to the class template
8140 itself and not a specialization thereof, and is not ambiguous. */
8142 {
8145 {
8151 }
8154 else
8156 }
8162 }
8164 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8165 parameters, find the desired type.
8167 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8169 IN_DECL, if non-NULL, is the template declaration we are trying to
8170 instantiate.
8172 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8173 the class we are looking up.
8175 Issue error and warning messages under control of COMPLAIN.
8177 If the template class is really a local class in a template
8178 function, then the FUNCTION_CONTEXT is the function in which it is
8179 being instantiated.
8181 ??? Note that this function is currently called *twice* for each
8182 template-id: the first time from the parser, while creating the
8183 incomplete type (finish_template_type), and the second type during the
8184 real instantiation (instantiate_template_class). This is surely something
8185 that we want to avoid. It also causes some problems with argument
8186 coercion (see convert_nontype_argument for more information on this). */
8188 static tree
8191 {
8193 tree t;
8196 spec_entry elt;
8197 hashval_t hash;
8200 {
8204 else
8205 {
8212 }
8215 }
8217 {
8220 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8221 an implicit typename for the second A. Deal with it. */
8226 {
8229 }
8230 }
8233 {
8236 }
8238 {
8242 }
8244 {
8247 }
8249 /* Issue an error message if we didn't find a template. */
8251 {
8255 }
8258 /* Make sure it's a user visible template, if it was named by
8259 the user. */
8262 {
8264 {
8268 }
8270 }
8274 /* An alias that just changes the name of a template is equivalent to the
8275 other template, so if any of the arguments are pack expansions, strip
8276 the alias to avoid problems with a pack expansion passed to a non-pack
8277 alias template parameter (DR 1430). */
8282 {
8283 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8284 template arguments */
8286 tree parm;
8287 tree arglist2;
8288 tree outer;
8292 /* Consider an example where a template template parameter declared as
8294 template <class T, class U = std::allocator<T> > class TT
8296 The template parameter level of T and U are one level larger than
8297 of TT. To proper process the default argument of U, say when an
8298 instantiation `TT<int>' is seen, we need to build the full
8299 arguments containing {int} as the innermost level. Outer levels,
8300 available when not appearing as default template argument, can be
8301 obtained from the arguments of the enclosing template.
8303 Suppose that TT is later substituted with std::vector. The above
8304 instantiation is `TT<int, std::allocator<T> >' with TT at
8305 level 1, and T at level 2, while the template arguments at level 1
8306 becomes {std::vector} and the inner level 2 is {int}. */
8312 {
8313 /* This is an argument of the current template, so we haven't set
8314 DECL_CONTEXT yet. */
8315 tree relevant_template_parms;
8317 /* Parameter levels that are greater than the level of the given
8318 template template parm are irrelevant. */
8325 }
8331 complain,
8341 }
8342 else
8343 {
8345 tree gen_tmpl;
8346 tree type_decl;
8354 /* An error occurred while building the template TEMPL, and a
8355 diagnostic has most certainly been emitted for that
8356 already. Let's propagate that error. */
8365 {
8366 /* We've been given an incomplete set of template arguments.
8367 For example, given:
8369 template <class T> struct S1 {
8370 template <class U> struct S2 {};
8371 template <class U> struct S2<U*> {};
8372 };
8374 we will be called with an ARGLIST of `U*', but the
8375 TEMPLATE will be `template <class T> template
8376 <class U> struct S1<T>::S2'. We must fill in the missing
8377 arguments. */
8378 arglist
8380 arglist);
8382 }
8384 /* Now we should have enough arguments. */
8387 /* From here on, we're only interested in the most general
8388 template. */
8390 /* Calculate the BOUND_ARGS. These will be the args that are
8391 actually tsubst'd into the definition to create the
8392 instantiation. */
8394 complain,
8399 /* We were unable to bind the arguments. */
8402 /* In the scope of a template class, explicit references to the
8403 template class refer to the type of the template, not any
8404 instantiation of it. For example, in:
8406 template <class T> class C { void f(C<T>); }
8408 the `C<T>' is just the same as `C'. Outside of the
8409 class, however, such a reference is an instantiation. */
8413 /* comp_template_args is expensive, check it last. */
8415 arglist))
8418 /* If we already have this specialization, return it. */
8428 /* If the the template's constraints are not satisfied,
8429 then we cannot form a valid type.
8431 Note that the check is deferred until after the hash
8432 lookup. This prevents redundant checks on previously
8433 instantiated specializations. */
8435 {
8437 {
8440 }
8442 }
8446 /* If the deduced arguments are invalid, then the binding
8447 failed. */
8451 complain))
8458 {
8463 }
8473 /* Create the type. */
8475 {
8476 /* The user referred to a specialization of an alias
8477 template represented by GEN_TMPL.
8479 [temp.alias]/2 says:
8481 When a template-id refers to the specialization of an
8482 alias template, it is equivalent to the associated
8483 type obtained by substitution of its
8484 template-arguments for the template-parameters in the
8485 type-id of the alias template. */
8488 /* Note that the call above (by indirectly calling
8489 register_specialization in tsubst_decl) registers the
8490 TYPE_DECL representing the specialization of the alias
8491 template. So next time someone substitutes ARGLIST for
8492 the template parms into the alias template (GEN_TMPL),
8493 she'll get that TYPE_DECL back. */
8497 }
8499 {
8501 {
8512 }
8513 else
8514 {
8515 /* We don't want to call start_enum for this type, since
8516 the values for the enumeration constants may involve
8517 template parameters. And, no one should be interested
8518 in the enumeration constants for such a type. */
8521 }
8525 }
8527 {
8533 /* A local class. Make sure the decl gets registered properly. */
8538 /* This instantiation is another name for the primary
8539 template type. Set the TYPE_CANONICAL field
8540 appropriately. */
8543 /* Some of the template arguments require structural
8544 equality testing, so this template class requires
8545 structural equality testing. */
8547 }
8548 else
8551 /* If we called start_enum or pushtag above, this information
8552 will already be set up. */
8554 {
8561 }
8562 else
8566 {
8572 {
8575 }
8576 }
8580 {
8584 {
8585 tree attributes
8593 }
8594 }
8596 /* Let's consider the explicit specialization of a member
8597 of a class template specialization that is implicitly instantiated,
8598 e.g.:
8599 template<class T>
8600 struct S
8601 {
8602 template<class U> struct M {}; //#0
8603 };
8605 template<>
8606 template<>
8607 struct S<int>::M<char> //#1
8608 {
8609 int i;
8610 };
8611 [temp.expl.spec]/4 says this is valid.
8613 In this case, when we write:
8614 S<int>::M<char> m;
8616 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8617 the one of #0.
8619 When we encounter #1, we want to store the partial instantiation
8620 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8622 For all cases other than this "explicit specialization of member of a
8623 class template", we just want to store the most general template into
8624 the CLASSTYPE_TI_TEMPLATE of M.
8626 This case of "explicit specialization of member of a class template"
8627 only happens when:
8628 1/ the enclosing class is an instantiation of, and therefore not
8629 the same as, the context of the most general template, and
8630 2/ we aren't looking at the partial instantiation itself, i.e.
8631 the innermost arguments are not the same as the innermost parms of
8632 the most general template.
8634 So it's only when 1/ and 2/ happens that we want to use the partial
8635 instantiation of the member template in lieu of its most general
8636 template. */
8640 /* the enclosing class must be an instantiation... */
8643 {
8644 tree partial_inst_args;
8647 partial_inst_args =
8655 use_partial_inst_tmpl =
8656 /*...and we must not be looking at the partial instantiation
8657 itself. */
8659 partial_inst_args);
8660 }
8663 /* This case is easy; there are no member templates involved. */
8665 else
8666 {
8667 /* This is a full instantiation of a member template. Find
8668 the partial instantiation of which this is an instance. */
8670 /* Temporarily reduce by one the number of levels in the ARGLIST
8671 so as to avoid comparing the last set of arguments. */
8675 /* FOUND is either a proper class type, or an alias
8676 template specialization. In the later case, it's a
8677 TYPE_DECL, resulting from the substituting of arguments
8678 for parameters in the TYPE_DECL of the alias template
8679 done earlier. So be careful while getting the template
8680 of FOUND. */
8682 ? found
8686 }
8688 // Build template info for the new specialization.
8697 /* Note this use of the partial instantiation so we can check it
8698 later in maybe_process_partial_specialization. */
8705 /* Now that the type has been registered on the instantiations
8706 list, we set up the enumerators. Because the enumeration
8707 constants may involve the enumeration type itself, we make
8708 sure to register the type first, and then create the
8709 constants. That way, doing tsubst_expr for the enumeration
8710 constants won't result in recursive calls here; we'll find
8711 the instantiation and exit above. */
8715 /* If the type makes use of template parameters, the
8716 code that generates debugging information will crash. */
8719 /* Possibly limit visibility based on template args. */
8726 }
8727 }
8729 /* Wrapper for lookup_template_class_1. */
8731 tree
8734 {
8735 tree ret;
8741 }
8743 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8745 tree
8747 {
8748 /* The type of the expression is NULL_TREE since the template-id could refer
8749 to an explicit or partial specialization. */
8752 /* Except that concepts are always bool. */
8755 }
8757 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8759 tree
8761 {
8765 /* We never want to return a VAR_DECL for a variable concept, since they
8766 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8780 {
8782 {
8785 }
8787 }
8789 /* If a template-id refers to a specialization of a variable
8790 concept, then the expression is true if and only if the
8791 concept's constraints are satisfied by the given template
8792 arguments.
8794 NOTE: This is an extension of Concepts Lite TS that
8795 allows constraints to be used in expressions. */
8797 {
8800 }
8803 }
8805 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
8806 TARGS template args, and instantiate it if it's not dependent. */
8808 static tree
8810 tsubst_flags_t complain)
8811 {
8814 {
8817 }
8820 }
8822 \f
8823 struct pair_fn_data
8824 {
8825 tree_fn_t fn;
8826 tree_fn_t any_fn;
8828 /* True when we should also visit template parameters that occur in
8829 non-deduced contexts. */
8832 };
8834 /* Called from for_each_template_parm via walk_tree. */
8836 static tree
8838 {
8845 #define WALK_SUBTREE(NODE) \
8846 do \
8847 { \
8848 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
8849 pfd->include_nondeduced_p, \
8850 pfd->any_fn); \
8851 if (result) goto out; \
8852 } \
8853 while (0)
8863 {
8867 /* Fall through. */
8873 else
8883 /* Since we're not going to walk subtrees, we have to do this
8884 explicitly here. */
8886 /* Fall through. */
8889 /* Check the return type. */
8892 /* Check the parameter types. Since default arguments are not
8893 instantiated until they are needed, the TYPE_ARG_TYPES may
8894 contain expressions that involve template parameters. But,
8895 no-one should be looking at them yet. And, once they're
8896 instantiated, they don't contain template parameters, so
8897 there's no point in looking at them then, either. */
8898 {
8899 tree parm;
8904 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8905 want walk_tree walking into them itself. */
8907 }
8910 {
8914 }
8931 /* Fall through. */
8943 /* Record template parameters such as `T' inside `TT<T>'. */
8945 /* Fall through. */
8955 /* In C++17 we can deduce a type argument from the type of a non-type
8956 argument. */
8963 /* A template template parameter is encountered. */
8967 /* Already substituted template template parameter */
8972 /* A template-id in a TYPENAME_TYPE might be a deduced context after
8973 partial instantiation. */
8985 /* If there's no type, then this thing must be some expression
8986 involving template parameters. */
9008 }
9010 #undef WALK_SUBTREE
9012 /* We didn't find any template parameters we liked. */
9013 out:
9015 }
9017 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9018 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9019 call FN with the parameter and the DATA.
9020 If FN returns nonzero, the iteration is terminated, and
9021 for_each_template_parm returns 1. Otherwise, the iteration
9022 continues. If FN never returns a nonzero value, the value
9023 returned by for_each_template_parm is 0. If FN is NULL, it is
9024 considered to be the function which always returns 1.
9026 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9027 parameters that occur in non-deduced contexts. When false, only
9028 visits those template parameters that can be deduced. */
9030 static tree
9034 tree_fn_t any_fn)
9035 {
9037 tree result;
9039 /* Set up. */
9045 /* Walk the tree. (Conceptually, we would like to walk without
9046 duplicates, but for_each_template_parm_r recursively calls
9047 for_each_template_parm, so we would need to reorganize a fair
9048 bit to use walk_tree_without_duplicates, so we keep our own
9049 visited list.) */
9052 else
9055 for_each_template_parm_r,
9059 /* Clean up. */
9061 {
9064 }
9067 }
9069 /* Returns true if T depends on any template parameter. */
9071 int
9073 {
9103 else
9104 {
9107 }
9112 }
9114 /* Returns true iff current_function_decl is an incompletely instantiated
9115 template. Useful instead of processing_template_decl because the latter
9116 is set to 0 during instantiate_non_dependent_expr. */
9118 bool
9120 {
9129 }
9131 /* Returns true if T depends on any template parameter with level LEVEL. */
9133 bool
9135 {
9138 }
9140 /* Returns true if the signature of DECL depends on any template parameter from
9141 its enclosing class. */
9143 bool
9145 {
9155 template_parm_outer_level,
9165 }
9167 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9168 ill-formed translation unit, i.e. a variable or function that isn't
9169 usable in a constant expression. */
9173 {
9177 }
9179 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9180 neglectable and instantiated from within an erroneous instantiation. */
9182 static bool
9184 {
9195 }
9203 /* We're starting to instantiate D; record the template instantiation context
9204 for diagnostics and to restore it later. */
9206 bool
9208 {
9210 }
9212 /* We're starting to instantiate D; record the template instantiation context
9213 at LOC for diagnostics and to restore it later. */
9215 bool
9217 {
9221 {
9222 /* Tell error.c not to try to instantiate any templates. */
9225 "template instantiation depth exceeds maximum of %d"
9227 max_tinst_depth);
9229 }
9231 /* If the current instantiation caused problems, don't let it instantiate
9232 anything else. Do allow deduction substitution and decls usable in
9233 constant expressions. */
9237 /* When not -quiet, dump template instantiations other than functions, since
9238 announce_function will take care of those. */
9257 }
9259 /* We're done instantiating this template; return to the instantiation
9260 context. */
9262 void
9264 {
9265 /* Restore the filename and line number stashed away when we started
9266 this instantiation. */
9270 }
9272 /* We're instantiating a deferred template; restore the template
9273 instantiation context in which the instantiation was requested, which
9274 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9276 static tree
9278 {
9290 }
9292 /* Returns the TINST_LEVEL which gives the original instantiation
9293 context. */
9297 {
9303 }
9305 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9306 vector of template arguments, as for tsubst.
9308 Returns an appropriate tsubst'd friend declaration. */
9310 static tree
9312 {
9313 tree new_friend;
9318 /* This was a friend declared with an explicit template
9319 argument list, e.g.:
9321 friend void f<>(T);
9323 to indicate that f was a template instantiation, not a new
9324 function declaration. Now, we have to figure out what
9325 instantiation of what template. */
9326 {
9328 tree new_args;
9329 tree tmpl;
9332 /* Friend functions are looked up in the containing namespace scope.
9333 We must enter that scope, to avoid finding member functions of the
9334 current class with same name. */
9349 tsk_none);
9351 }
9355 /* The NEW_FRIEND will look like an instantiation, to the
9356 compiler, but is not an instantiation from the point of view of
9357 the language. For example, we might have had:
9359 template <class T> struct S {
9360 template <class U> friend void f(T, U);
9361 };
9363 Then, in S<int>, template <class U> void f(int, U) is not an
9364 instantiation of anything. */
9370 {
9374 }
9376 /* The mangled name for the NEW_FRIEND is incorrect. The function
9377 is not a template instantiation and should not be mangled like
9378 one. Therefore, we forget the mangling here; we'll recompute it
9379 later if we need it. */
9381 {
9384 }
9387 {
9388 tree old_decl;
9389 tree new_friend_template_info;
9390 tree new_friend_result_template_info;
9391 tree ns;
9394 /* We must save some information from NEW_FRIEND before calling
9395 duplicate decls since that function will free NEW_FRIEND if
9396 possible. */
9398 new_friend_is_defn =
9403 {
9404 /* This declaration is a `primary' template. */
9407 new_friend_result_template_info
9409 }
9410 else
9413 /* Inside pushdecl_namespace_level, we will push into the
9414 current namespace. However, the friend function should go
9415 into the namespace of the template. */
9425 {
9426 /* This new friend declaration matched an existing
9427 declaration. For example, given:
9429 template <class T> void f(T);
9430 template <class U> class C {
9431 template <class T> friend void f(T) {}
9432 };
9434 the friend declaration actually provides the definition
9435 of `f', once C has been instantiated for some type. So,
9436 old_decl will be the out-of-class template declaration,
9437 while new_friend is the in-class definition.
9439 But, if `f' was called before this point, the
9440 instantiation of `f' will have DECL_TI_ARGS corresponding
9441 to `T' but not to `U', references to which might appear
9442 in the definition of `f'. Previously, the most general
9443 template for an instantiation of `f' was the out-of-class
9444 version; now it is the in-class version. Therefore, we
9445 run through all specialization of `f', adding to their
9446 DECL_TI_ARGS appropriately. In particular, they need a
9447 new set of outer arguments, corresponding to the
9448 arguments for this class instantiation.
9450 The same situation can arise with something like this:
9452 friend void f(int);
9453 template <class T> class C {
9454 friend void f(T) {}
9455 };
9457 when `C<int>' is instantiated. Now, `f(int)' is defined
9458 in the class. */
9461 /* On the other hand, if the in-class declaration does
9462 *not* provide a definition, then we don't want to alter
9463 existing definitions. We can just leave everything
9464 alone. */
9465 ;
9466 else
9467 {
9471 /* Overwrite whatever template info was there before, if
9472 any, with the new template information pertaining to
9473 the declaration. */
9477 {
9478 /* We should have called reregister_specialization in
9479 duplicate_decls. */
9484 /* Instantiate it if the global has already been used. */
9488 }
9489 else
9490 {
9491 tree t;
9493 /* Indicate that the old function template is a partial
9494 instantiation. */
9502 /* Reassign any specializations already in the hash table
9503 to the new more general template, and add the
9504 additional template args. */
9508 {
9510 spec_entry elt;
9522 register_specialization
9525 }
9527 }
9528 }
9530 /* The information from NEW_FRIEND has been merged into OLD_DECL
9531 by duplicate_decls. */
9533 }
9534 }
9535 else
9536 {
9540 /* In the code
9541 template <class T> class C {
9542 template <class U> friend void C1<U>::f (); // case 1
9543 friend void C2<T>::f (); // case 2
9544 };
9545 we only need to make sure CONTEXT is a complete type for
9546 case 2. To distinguish between the two cases, we note that
9547 CONTEXT of case 1 remains dependent type after tsubst while
9548 this isn't true for case 2. */
9558 {
9560 /* do_friend adds the TEMPLATE_DECL for any member friend
9561 template even if it isn't a member template, i.e.
9562 template <class T> friend A<T>::f();
9563 Look through it in that case. */
9567 /* Check to see that the declaration is really present, and,
9568 possibly obtain an improved declaration. */
9573 }
9574 }
9577 }
9579 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9580 template arguments, as for tsubst.
9582 Returns an appropriate tsubst'd friend type or error_mark_node on
9583 failure. */
9585 static tree
9587 {
9588 tree friend_type;
9589 tree tmpl;
9590 tree context;
9593 {
9596 }
9601 {
9604 else
9606 }
9608 /* Look for a class template declaration. We look for hidden names
9609 because two friend declarations of the same template are the
9610 same. For example, in:
9612 struct A {
9613 template <typename> friend class F;
9614 };
9615 template <typename> struct B {
9616 template <typename> friend class F;
9617 };
9619 both F templates are the same. */
9623 /* But, if we don't find one, it might be because we're in a
9624 situation like this:
9626 template <class T>
9627 struct S {
9628 template <class U>
9629 friend struct S;
9630 };
9632 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9633 for `S<int>', not the TEMPLATE_DECL. */
9635 {
9638 }
9641 {
9642 /* The friend template has already been declared. Just
9643 check to see that the declarations match, and install any new
9644 default parameters. We must tsubst the default parameters,
9645 of course. We only need the innermost template parameters
9646 because that is all that redeclare_class_template will look
9647 at. */
9650 {
9651 tree parms;
9652 location_t saved_input_location;
9662 }
9665 }
9666 else
9667 {
9668 /* The friend template has not already been declared. In this
9669 case, the instantiation of the template class will cause the
9670 injection of this template into the global scope. */
9675 /* The new TMPL is not an instantiation of anything, so we
9676 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9677 the new type because that is supposed to be the corresponding
9678 template decl, i.e., TMPL. */
9685 /* Inject this template into the global scope. */
9687 }
9690 {
9693 else
9695 }
9698 }
9700 /* Returns zero if TYPE cannot be completed later due to circularity.
9701 Otherwise returns one. */
9703 static int
9705 {
9715 else
9717 }
9722 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9723 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9725 static tree
9728 {
9737 {
9744 clauses
9748 else
9750 }
9751 /* If the first attribute argument is an identifier, don't
9752 pass it through tsubst. Attributes like mode, format,
9753 cleanup and several target specific attributes expect it
9754 unmodified. */
9756 {
9757 tree chain
9762 }
9764 {
9765 /* An attribute pack expansion. */
9772 {
9776 }
9778 }
9779 else
9786 }
9788 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
9789 unchanged or a new TREE_LIST chain. */
9791 static tree
9794 {
9799 {
9803 }
9807 {
9810 {
9813 {
9815 do
9820 }
9821 }
9823 }
9826 }
9828 /* Apply any attributes which had to be deferred until instantiation
9829 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9830 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9832 static void
9835 {
9837 tree t;
9842 {
9846 }
9849 {
9853 }
9854 else
9858 {
9863 {
9866 {
9870 do
9873 }
9874 else
9876 }
9879 }
9880 }
9882 /* Perform (or defer) access check for typedefs that were referenced
9883 from within the template TMPL code.
9884 This is a subroutine of instantiate_decl and instantiate_class_template.
9885 TMPL is the template to consider and TARGS is the list of arguments of
9886 that template. */
9888 static void
9890 {
9891 location_t saved_location;
9902 {
9914 /* Make access check error messages point to the location
9915 of the use of the typedef. */
9919 tf_warning_or_error);
9920 }
9922 }
9924 static tree
9926 {
9928 tree typedecl;
9929 tree pbinfo;
9930 tree base_list;
9932 tree fn_context;
9941 /* Figure out which template is being instantiated. */
9945 /* Determine what specialization of the original template to
9946 instantiate. */
9949 {
9952 }
9954 {
9955 /* This TYPE is actually an instantiation of a partial
9956 specialization. We replace the innermost set of ARGS with
9957 the arguments appropriate for substitution. For example,
9958 given:
9960 template <class T> struct S {};
9961 template <class T> struct S<T*> {};
9963 and supposing that we are instantiating S<int*>, ARGS will
9964 presently be {int*} -- but we need {int}. */
9967 }
9968 else
9969 {
9972 }
9974 /* If the template we're instantiating is incomplete, then clearly
9975 there's nothing we can do. */
9979 /* If we've recursively instantiated too many templates, stop. */
9983 /* Now we're really doing the instantiation. Mark the type as in
9984 the process of being defined. */
9987 /* We may be in the middle of deferred access check. Disable
9988 it now. */
9995 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10000 else
10001 {
10004 }
10005 /* Use #pragma pack from the template context. */
10011 /* Set the input location to the most specialized template definition.
10012 This is needed if tsubsting causes an error. */
10023 {
10026 /* Adjust visibility for template arguments. */
10028 }
10034 /* We should never instantiate a nested class before its enclosing
10035 class; we need to look up the nested class by name before we can
10036 instantiate it, and that lookup should instantiate the enclosing
10037 class. */
10043 {
10044 tree pbase_binfo;
10045 tree pushed_scope;
10048 /* We must enter the scope containing the type, as that is where
10049 the accessibility of types named in dependent bases are
10050 looked up from. */
10053 /* Substitute into each of the bases to determine the actual
10054 basetypes. */
10056 {
10057 tree base;
10063 {
10064 expanded_bases =
10071 }
10074 {
10076 /* Extract the already-expanded base class. */
10078 else
10079 /* Substitute to figure out the base class. */
10081 NULL_TREE);
10089 }
10090 }
10092 /* The list is now in reverse order; correct that. */
10097 }
10098 /* Now call xref_basetypes to set up all the base-class
10099 information. */
10107 /* Now that our base classes are set up, enter the scope of the
10108 class, so that name lookups into base classes, etc. will work
10109 correctly. This is precisely analogous to what we do in
10110 begin_class_definition when defining an ordinary non-template
10111 class, except we also need to push the enclosing classes. */
10114 /* Now members are processed in the order of declaration. */
10117 {
10121 {
10123 {
10124 /* Build new CLASSTYPE_NESTED_UTDS. */
10126 tree newtag;
10132 /* If the member is a class template, then -- even after
10133 substitution -- there may be dependent types in the
10134 template argument list for the class. We increment
10135 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10136 that function will assume that no types are dependent
10137 when outside of a template. */
10147 {
10151 /* Unfortunately, lookup_template_class sets
10152 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10153 instantiation (i.e., for the type of a member
10154 template class nested within a template class.)
10155 This behavior is required for
10156 maybe_process_partial_specialization to work
10157 correctly, but is not accurate in this case;
10158 the TAG is not an instantiation of anything.
10159 (The corresponding TEMPLATE_DECL is an
10160 instantiation, but the TYPE is not.) */
10163 /* Now, we call pushtag to put this NEWTAG into the scope of
10164 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10165 pushtag calling push_template_decl. We don't have to do
10166 this for enums because it will already have been done in
10167 tsubst_enum. */
10171 }
10172 }
10174 {
10175 /* Build new TYPE_METHODS. */
10176 tree r;
10185 /* Instantiate members marked with attribute used. */
10191 }
10194 /* A closure type for a lambda in a default argument for a
10195 member template. Ignore it; it will be instantiated with
10197 else
10198 {
10199 /* Build new TYPE_FIELDS. */
10201 {
10202 tree condition;
10205 condition =
10215 }
10217 {
10218 tree r;
10222 /* The file and line for this declaration, to
10223 assist in error message reporting. Since we
10224 called push_tinst_level above, we don't need to
10225 restore these. */
10235 {
10236 /* A capture pack became multiple fields. */
10239 }
10242 {
10246 {
10247 /* In [temp.inst]:
10249 [t]he initialization (and any associated
10250 side-effects) of a static data member does
10251 not occur unless the static data member is
10252 itself used in a way that requires the
10253 definition of the static data member to
10254 exist.
10256 Therefore, we do not substitute into the
10257 initialized for the static data member here. */
10258 finish_static_data_member_decl
10264 /* Instantiate members marked with attribute used. */
10267 }
10269 {
10270 /* Determine whether R has a valid type and can be
10271 completed later. If R is invalid, then its type
10272 is replaced by error_mark_node. */
10278 {
10279 /* If R's type couldn't be completed and
10280 it isn't a flexible array member (whose
10281 type is incomplete by definition) give
10282 an error. */
10285 }
10286 }
10288 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10289 such a thing will already have been added to the field
10290 list by tsubst_enum in finish_member_declaration in the
10291 CLASSTYPE_NESTED_UTDS case above. */
10295 {
10298 }
10299 }
10300 }
10301 }
10302 }
10303 else
10304 {
10307 {
10308 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10314 {
10315 /* template <class T> friend class C; */
10318 }
10320 {
10321 /* template <class T> friend class C::D; */
10327 }
10330 {
10331 /* This could be either
10333 friend class T::C;
10335 when dependent_type_p is false or
10337 template <class U> friend class T::C;
10339 otherwise. */
10340 /* Bump processing_template_decl in case this is something like
10341 template <class T> friend struct A<T>::B. */
10348 }
10351 {
10352 /* friend class C;
10354 where C hasn't been declared yet. Let's lookup name
10355 from namespace scope directly, bypassing any name that
10356 come from dependent base class. */
10359 /* The call to xref_tag_from_type does injection for friend
10360 classes. */
10362 friend_type =
10366 }
10368 /* friend class C<T>; */
10371 /* Otherwise it's
10373 friend class C;
10375 where C is already declared or
10377 friend class C<int>;
10379 We don't have to do anything in these cases. */
10382 /* Trick make_friend_class into realizing that the friend
10383 we're adding is a template, not an ordinary class. It's
10384 important that we use make_friend_class since it will
10385 perform some error-checking and output cross-reference
10386 information. */
10394 }
10395 else
10396 {
10397 /* Build new DECL_FRIENDLIST. */
10398 tree r;
10400 /* The file and line for this declaration, to
10401 assist in error message reporting. Since we
10402 called push_tinst_level above, we don't need to
10403 restore these. */
10407 {
10410 }
10415 {
10418 }
10419 }
10420 }
10421 }
10424 {
10425 /* Restore these before substituting into the lambda capture
10426 initializers. */
10429 }
10432 {
10435 {
10441 {
10442 /* Set function_depth to avoid garbage collection. */
10446 }
10448 /* We need to instantiate the capture list from the template
10449 after we've instantiated the closure members, but before we
10450 consider adding the conversion op. Also keep any captures
10451 that may have been added during instantiation of the op(). */
10453 tree tmpl_cap
10462 }
10463 else
10465 }
10467 /* Set the file and line number information to whatever is given for
10468 the class itself. This puts error messages involving generated
10469 implicit functions at a predictable point, and the same point
10470 that would be used for non-template classes. */
10477 /* We don't instantiate default arguments for member functions. 14.7.1:
10479 The implicit instantiation of a class template specialization causes
10480 the implicit instantiation of the declarations, but not of the
10481 definitions or default arguments, of the class member functions,
10482 member classes, static data members and member templates.... */
10484 /* Some typedefs referenced from within the template code need to be access
10485 checked at template instantiation time, i.e now. These types were
10486 added to the template at parsing time. Let's get those and perform
10487 the access checks then. */
10497 /* The vtable for a template class can be emitted in any translation
10498 unit in which the class is instantiated. When there is no key
10499 method, however, finish_struct_1 will already have added TYPE to
10500 the keyed_classes list. */
10505 }
10507 /* Wrapper for instantiate_class_template_1. */
10509 tree
10511 {
10512 tree ret;
10517 }
10519 static tree
10521 {
10522 tree r;
10528 else
10529 {
10536 }
10538 }
10540 /* Given a function parameter pack TMPL_PARM and some function parameters
10541 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10542 and set *SPEC_P to point at the next point in the list. */
10544 tree
10546 {
10547 /* Collect all of the extra "packed" parameters into an
10548 argument pack. */
10549 tree parmvec;
10550 tree parmtypevec;
10561 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10566 {
10569 }
10571 /* Build the argument packs. */
10578 }
10580 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10581 NONTYPE_ARGUMENT_PACK. */
10583 static tree
10585 {
10587 }
10589 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10590 pack expansion with no extra args, 2 if it has extra args, or 0
10591 if it is not a pack expansion. */
10593 static int
10595 {
10601 /* A decl pack is itself an expansion. */
10608 }
10611 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10613 static tree
10615 {
10622 }
10624 /* This is a subroutine of tsubst_pack_expansion.
10626 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10627 mechanism to store the (non complete list of) arguments of the
10628 substitution and return a non substituted pack expansion, in order
10629 to wait for when we have enough arguments to really perform the
10630 substitution. */
10632 static bool
10636 {
10637 /* If one pack has an expansion and another pack has a normal
10638 argument or if one pack has an empty argument and an another
10639 one hasn't then tsubst_pack_expansion cannot perform the
10640 substitution and need to fall back on the
10641 PACK_EXPANSION_EXTRA mechanism. */
10649 {
10652 parm_pack;
10654 {
10659 /* We can't substitute a pack expansion with extra args into
10660 our pattern. */
10664 else
10666 }
10670 }
10672 }
10674 /* [temp.variadic]/6 says that:
10676 The instantiation of a pack expansion [...]
10677 produces a list E1,E2, ..., En, where N is the number of elements
10678 in the pack expansion parameters.
10680 This subroutine of tsubst_pack_expansion produces one of these Ei.
10682 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10683 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10684 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10685 INDEX is the index 'i' of the element Ei to produce. ARGS,
10686 COMPLAIN, and IN_DECL are the same parameters as for the
10687 tsubst_pack_expansion function.
10689 The function returns the resulting Ei upon successful completion,
10690 or error_mark_node.
10692 Note that this function possibly modifies the ARGS parameter, so
10693 it's the responsibility of the caller to restore it. */
10695 static tree
10697 tree parm_packs,
10699 tree args /* This parm gets
10701 tsubst_flags_t complain,
10702 tree in_decl)
10703 {
10704 tree t;
10707 /* For each parameter pack, change the substitution of the parameter
10708 pack to the ith argument in its argument pack, then expand the
10709 pattern. */
10711 {
10716 ith_elem_is_expansion |=
10719 /* Select the Ith argument from the pack. */
10722 {
10724 {
10729 }
10730 else
10732 }
10733 else
10734 {
10739 {
10741 /* Update the corresponding argument. */
10743 }
10744 else
10745 /* Re-use the ARGUMENT_PACK_SELECT. */
10747 }
10749 }
10751 /* Substitute into the PATTERN with the (possibly altered)
10752 arguments. */
10754 /* Expanding a fixed parameter pack from
10755 coerce_template_parameter_pack. */
10760 {
10763 else
10766 }
10770 else
10773 /* If the Ith argument pack element is a pack expansion, then
10774 the Ith element resulting from the substituting is going to
10775 be a pack expansion as well. */
10780 }
10782 /* When the unexpanded parameter pack in a fold expression expands to an empty
10783 sequence, the value of the expression is as follows; the program is
10784 ill-formed if the operator is not listed in this table.
10786 && true
10787 || false
10788 , void() */
10790 tree
10792 {
10796 {
10805 }
10811 }
10813 /* Given a fold-expression T and a current LEFT and RIGHT operand,
10814 form an expression that combines the two terms using the
10815 operator of T. */
10817 static tree
10819 {
10823 // Handle compound assignment operators.
10828 {
10838 complain);
10839 }
10840 }
10842 /* Substitute ARGS into the pack of a fold expression T. */
10846 {
10848 }
10850 /* Substitute ARGS into the pack of a fold expression T. */
10854 {
10856 }
10858 /* Expand a PACK of arguments into a grouped as left fold.
10859 Given a pack containing elements A0, A1, ..., An and an
10860 operator @, this builds the expression:
10862 ((A0 @ A1) @ A2) ... @ An
10864 Note that PACK must not be empty.
10866 The operator is defined by the original fold expression T. */
10868 static tree
10870 {
10873 {
10876 }
10878 }
10880 /* Substitute into a unary left fold expression. */
10882 static tree
10884 tree in_decl)
10885 {
10890 {
10894 }
10897 else
10899 }
10901 /* Substitute into a binary left fold expression.
10903 Do ths by building a single (non-empty) vector of argumnts and
10904 building the expression from those elements. */
10906 static tree
10908 tree in_decl)
10909 {
10918 {
10923 }
10931 }
10933 /* Expand a PACK of arguments into a grouped as right fold.
10934 Given a pack containing elementns A0, A1, ..., and an
10935 operator @, this builds the expression:
10937 A0@ ... (An-2 @ (An-1 @ An))
10939 Note that PACK must not be empty.
10941 The operator is defined by the original fold expression T. */
10943 tree
10945 {
10946 // Build the expression.
10950 {
10953 }
10955 }
10957 /* Substitute into a unary right fold expression. */
10959 static tree
10961 tree in_decl)
10962 {
10967 {
10971 }
10974 else
10976 }
10978 /* Substitute into a binary right fold expression.
10980 Do ths by building a single (non-empty) vector of arguments and
10981 building the expression from those elements. */
10983 static tree
10985 tree in_decl)
10986 {
10995 {
11000 }
11009 }
11012 /* Substitute ARGS into T, which is an pack expansion
11013 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11014 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11015 (if only a partial substitution could be performed) or
11016 ERROR_MARK_NODE if there was an error. */
11017 tree
11019 tree in_decl)
11020 {
11021 tree pattern;
11025 tree result;
11033 /* Add in any args remembered from an earlier partial instantiation. */
11038 /* Determine the argument packs that will instantiate the parameter
11039 packs used in the expansion expression. While we're at it,
11040 compute the number of arguments to be expanded and make sure it
11041 is consistent. */
11044 {
11051 {
11055 else
11058 }
11060 {
11061 /* We know we have correct local_specializations if this
11062 expansion is at function scope, or if we're dealing with a
11063 local parameter in a requires expression; for the latter,
11064 tsubst_requires_expr set it up appropriately. */
11067 else
11068 /* We can't rely on local_specializations for a parameter
11069 name used later in a function declaration (such as in a
11070 late-specified return type). Even if it exists, it might
11071 have the wrong value for a recursive call. */
11075 {
11076 /* This parameter pack was used in an unevaluated context. Just
11077 make a dummy decl, since it's only used for its type. */
11080 /* Partial instantiation of the parm_pack, we can't build
11081 up an argument pack yet. */
11083 else
11085 }
11086 }
11089 else
11090 {
11096 }
11103 /* This can only happen if we forget to expand an argument
11104 pack somewhere else. Just return an error, silently. */
11105 {
11109 }
11112 {
11116 /* Don't bother trying to do a partial substitution with
11117 incomplete packs; we'll try again after deduction. */
11124 {
11130 pattern);
11131 else
11134 pattern);
11136 }
11138 /* Keep track of the parameter packs and their corresponding
11139 argument packs. */
11142 }
11143 else
11144 {
11145 /* We can't substitute for this parameter pack. We use a flag as
11146 well as the missing_level counter because function parameter
11147 packs don't have a level. */
11150 }
11151 }
11153 /* If the expansion is just T..., return the matching argument pack, unless
11154 we need to call convert_from_reference on all the elements. This is an
11155 important optimization; see c++/68422. */
11158 {
11160 /* Types need no adjustment, nor does sizeof..., and if we still have
11161 some pack expansion args we won't do anything yet. */
11166 /* Also optimize expression pack expansions if we can tell that the
11167 elements won't have reference type. */
11173 /* Otherwise use the normal path so we get convert_from_reference. */
11174 }
11176 /* We cannot expand this expansion expression, because we don't have
11177 all of the argument packs we need. */
11179 {
11180 /* We got some full packs, but we can't substitute them in until we
11181 have values for all the packs. So remember these until then. */
11186 }
11188 {
11189 /* There were no real arguments, we're just replacing a parameter
11190 pack with another version of itself. Substitute into the
11191 pattern and return a PACK_EXPANSION_*. The caller will need to
11192 deal with that. */
11196 else
11200 }
11205 {
11206 /* We're in a late-specified return type, so create our own local
11207 specializations map; the current map is either NULL or (in the
11208 case of recursive unification) might have bindings that we don't
11209 want to use or alter. */
11212 }
11214 /* For each argument in each argument pack, substitute into the
11215 pattern. */
11219 {
11221 i,
11223 in_decl);
11226 {
11229 }
11230 }
11232 /* Update ARGS to restore the substitution from parameter packs to
11233 their argument packs. */
11235 {
11241 else
11242 {
11250 /* Update the corresponding argument. */
11254 else
11256 }
11257 }
11260 {
11263 }
11265 /* If the dependent pack arguments were such that we end up with only a
11266 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11272 }
11274 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11275 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11276 parameter packs; all parms generated from a function parameter pack will
11277 have the same DECL_PARM_INDEX. */
11279 tree
11281 {
11283 tree patparm;
11286 {
11292 }
11293 else
11294 {
11299 }
11302 }
11304 /* Make an argument pack out of the TREE_VEC VEC. */
11306 static tree
11308 {
11309 tree pack;
11313 else
11314 {
11318 }
11321 }
11323 /* Return an exact copy of template args T that can be modified
11324 independently. */
11326 static tree
11328 {
11336 {
11341 }
11347 }
11349 /* Substitute ARGS into the vector or list of template arguments T. */
11351 static tree
11353 {
11365 {
11367 tree new_arg;
11372 {
11373 /* Substitute into an expansion expression. */
11377 /* Add to the expanded length adjustment the number of
11378 expanded arguments. We subtract one from this
11379 measurement, because the argument pack expression
11380 itself is already counted as 1 in
11381 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11382 the argument pack is empty. */
11384 }
11386 {
11387 /* Substitute into each of the arguments. */
11393 new_arg,
11407 }
11408 }
11409 else
11418 }
11423 /* Make space for the expanded arguments coming from template
11424 argument packs. */
11426 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11427 arguments for a member template.
11428 In that case each TREE_VEC in ORIG_T represents a level of template
11429 arguments, and ORIG_T won't carry any non defaulted argument count.
11430 It will rather be the nested TREE_VECs that will carry one.
11431 In other words, ORIG_T carries a non defaulted argument count only
11432 if it doesn't contain any nested TREE_VEC. */
11434 {
11438 }
11440 {
11444 {
11447 /* Now expand the template argument pack "in place". */
11450 }
11451 else
11452 {
11454 out++;
11455 }
11456 }
11459 }
11461 /* Substitute ARGS into one level PARMS of template parameters. */
11463 static tree
11465 {
11472 {
11480 }
11483 }
11485 /* Return the result of substituting ARGS into the template parameters
11486 given by PARMS. If there are m levels of ARGS and m + n levels of
11487 PARMS, then the result will contain n levels of PARMS. For
11488 example, if PARMS is `template <class T> template <class U>
11489 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11490 result will be `template <int*, double, class V>'. */
11492 static tree
11494 {
11498 /* When substituting into a template, we must set
11499 PROCESSING_TEMPLATE_DECL as the template parameters may be
11500 dependent if they are based on one-another, and the dependency
11501 predicates are short-circuit outside of templates. */
11508 {
11515 }
11520 }
11522 /* Return the result of substituting ARGS into one template parameter
11523 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11524 parameter and which TREE_PURPOSE is the default argument of the
11525 template parameter. */
11527 static tree
11529 {
11550 }
11552 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11553 type T. If T is not an aggregate or enumeration type, it is
11554 handled as if by tsubst. IN_DECL is as for tsubst. If
11555 ENTERING_SCOPE is nonzero, T is the context for a template which
11556 we are presently tsubst'ing. Return the substituted value. */
11558 static tree
11560 tree args,
11561 tsubst_flags_t complain,
11562 tree in_decl,
11564 {
11569 {
11574 /* Fall through. */
11578 {
11579 tree argvec;
11580 tree context;
11581 tree r;
11585 /* In "sizeof(X<I>)" we need to evaluate "I". */
11591 /* First, determine the context for the type we are looking
11592 up. */
11595 {
11598 /* If context is a nested class inside a class template,
11599 it may still need to be instantiated (c++/33959). */
11601 }
11603 /* Then, figure out what arguments are appropriate for the
11604 type we are trying to find. For example, given:
11606 template <class T> struct S;
11607 template <class T, class U> void f(T, U) { S<U> su; }
11609 and supposing that we are instantiating f<int, double>,
11610 then our ARGS will be {int, double}, but, when looking up
11611 S we only want {double}. */
11616 else
11617 {
11621 }
11627 }
11628 else
11629 /* This is not a template type, so there's nothing to do. */
11634 }
11635 }
11637 /* Substitute into the default argument ARG (a default argument for
11638 FN), which has the indicated TYPE. */
11640 tree
11642 {
11647 /* This can happen in invalid code. */
11651 /* This default argument came from a template. Instantiate the
11652 default argument here, not in tsubst. In the case of
11653 something like:
11655 template <class T>
11656 struct S {
11657 static T t();
11658 void f(T = t());
11659 };
11661 we must be careful to do name lookup in the scope of S<T>,
11662 rather than in the current class. */
11664 /* The "this" pointer is not valid in a default argument. */
11666 {
11671 }
11674 /* The default argument expression may cause implicitly defined
11675 member functions to be synthesized, which will result in garbage
11676 collection. We must treat this situation as if we were within
11677 the body of function so as to avoid collecting live data on the
11678 stack. */
11686 /* Restore the "this" pointer. */
11688 {
11691 }
11698 /* Make sure the default argument is reasonable. */
11704 }
11706 /* Substitute into all the default arguments for FN. */
11708 static void
11710 {
11711 tree arg;
11712 tree tmpl_args;
11716 /* If this function is not yet instantiated, we certainly don't need
11717 its default arguments. */
11720 /* Don't do this again for clones. */
11725 arg;
11731 complain);
11732 }
11734 /* Substitute the ARGS into the T, which is a _DECL. Return the
11735 result of the substitution. Issue error and warning messages under
11736 control of COMPLAIN. */
11738 static tree
11740 {
11741 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11742 location_t saved_loc;
11747 /* Set the filename and linenumber to improve error-reporting. */
11752 {
11754 {
11755 /* We can get here when processing a member function template,
11756 member class template, or template template parameter. */
11758 tree spec;
11759 tree tmpl_args;
11760 tree full_args;
11763 {
11764 /* Template template parameter is treated here. */
11768 /* If we get a real template back, return it. This can happen in
11769 the context of most_specialized_partial_spec. */
11772 else
11773 /* The new TEMPLATE_DECL was built in
11774 reduce_template_parm_level. */
11777 }
11779 /* We might already have an instance of this template.
11780 The ARGS are for the surrounding class type, so the
11781 full args contain the tsubst'd args for the context,
11782 plus the innermost args from the template decl. */
11786 /* Because this is a template, the arguments will still be
11787 dependent, even after substitution. If
11788 PROCESSING_TEMPLATE_DECL is not set, the dependency
11789 predicates will short-circuit. */
11797 /* If this is a default template template argument,
11798 tsubst might not have changed anything. */
11805 {
11808 }
11810 /* Make a new template decl. It will be similar to the
11811 original, but will record the current template arguments.
11812 We also create a new function declaration, which is just
11813 like the old one, but points to this new template, rather
11814 than the old one. */
11819 // Build new template info linking to the original template decl.
11824 {
11825 tree new_type;
11833 /* For a partial specialization, we need to keep pointing to
11834 the primary template. */
11840 }
11841 else
11842 {
11843 tree new_decl;
11855 }
11861 /* The template parameters for this new template are all the
11862 template parameters for the old template, except the
11863 outermost level of parameters. */
11866 complain);
11872 /* Record this non-type partial instantiation. */
11876 }
11880 {
11881 tree ctx;
11884 tree gen_tmpl;
11885 tree type;
11890 /* Nobody should be tsubst'ing into non-template functions. */
11894 {
11895 tree spec;
11897 /* If T is not dependent, just return it. */
11901 /* Calculate the most general template of which R is a
11902 specialization, and the complete set of arguments used to
11903 specialize R. */
11906 (DECL_TEMPLATE_RESULT
11912 /* Check to see if we already have this specialization. */
11917 {
11920 }
11922 /* We can see more levels of arguments than parameters if
11923 there was a specialization of a member template, like
11924 this:
11926 template <class T> struct S { template <class U> void f(); }
11927 template <> template <class U> void S<int>::f(U);
11929 Here, we'll be substituting into the specialization,
11930 because that's where we can find the code we actually
11931 want to generate, but we'll have enough arguments for
11932 the most general template.
11934 We also deal with the peculiar case:
11936 template <class T> struct S {
11937 template <class U> friend void f();
11938 };
11939 template <class U> void f() {}
11940 template S<int>;
11941 template void f<double>();
11943 Here, the ARGS for the instantiation of will be {int,
11944 double}. But, we only need as many ARGS as there are
11945 levels of template parameters in CODE_PATTERN. We are
11946 careful not to get fooled into reducing the ARGS in
11947 situations like:
11949 template <class T> struct S { template <class U> void f(U); }
11950 template <class T> template <> void S<T>::f(int) {}
11952 which we can spot because the pattern will be a
11953 specialization in this case. */
11955 parms_depth =
11960 }
11961 else
11962 {
11963 /* This special case arises when we have something like this:
11965 template <class T> struct S {
11966 friend void f<int>(int, double);
11967 };
11969 Here, the DECL_TI_TEMPLATE for the friend declaration
11970 will be an IDENTIFIER_NODE. We are being called from
11971 tsubst_friend_function, and we want only to create a
11972 new decl (R) with appropriate types so that we can call
11973 determine_specialization. */
11975 }
11978 {
11981 else
11985 }
11986 else
11987 {
11990 }
11995 /* If we hit excessive deduction depth, the type is bogus even if
11996 it isn't error_mark_node, so don't build a decl. */
12000 /* We do NOT check for matching decls pushed separately at this
12001 point, as they may not represent instantiations of this
12002 template, and in any case are considered separate under the
12003 discrete model. */
12007 /* Clear out the mangled name and RTL for the instantiation. */
12010 /* Leave DECL_INITIAL set on deleted instantiations. */
12015 /* OpenMP UDRs have the only argument a reference to the declared
12016 type. We want to diagnose if the declared type is a reference,
12017 which is invalid, but as references to references are usually
12018 quietly merged, diagnose it here. */
12020 {
12021 tree argtype
12026 "reference type %qT in "
12030 argtype);
12031 }
12034 /* Type-conversion operator. Reconstruct the name, in
12035 case it's the name of one of the template's parameters. */
12045 /* If this is an instantiation of a function with internal
12046 linkage, we already know what object file linkage will be
12047 assigned to the instantiation. */
12056 /* We'll re-clone as appropriate in instantiate_template. */
12059 /* If we aren't complaining now, return on error before we register
12060 the specialization so that we'll complain eventually. */
12066 /* When instantiating a constrained member, substitute
12067 into the constraints to create a new constraint. */
12070 {
12073 }
12075 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12076 this in the special friend case mentioned above where
12077 GEN_TMPL is NULL. */
12079 {
12084 tree new_r
12087 /* We instantiated this while substituting into
12088 the type earlier (template/friend54.C). */
12091 /* We're not supposed to instantiate default arguments
12092 until they are called, for a template. But, for a
12093 declaration like:
12095 template <class T> void f ()
12096 { extern void g(int i = T()); }
12098 we should do the substitution when the template is
12099 instantiated. We handle the member function case in
12100 instantiate_class_template since the default arguments
12101 might refer to other members of the class. */
12106 }
12107 else
12110 /* Copy the list of befriending classes. */
12114 {
12118 in_decl);
12119 }
12122 {
12128 /* If this is an instantiation of a member template, clone it.
12129 If it isn't, that'll be handled by
12130 clone_constructors_and_destructors. */
12133 }
12144 /* Possibly limit visibility based on template args. */
12147 {
12151 }
12159 }
12163 {
12171 {
12172 /* If there is a local specialization that isn't a
12173 parameter pack, it means that we're doing a "simple"
12174 substitution from inside tsubst_pack_expansion. Just
12175 return the local specialization (which will be a single
12176 parm). */
12183 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12184 the parameters in this function parameter pack. */
12188 {
12191 /* Zero-length parameter packs are boring. Just substitute
12192 into the chain. */
12196 }
12197 else
12198 {
12199 /* All we did was update the type. Make a note of that. */
12202 }
12203 }
12205 /* Loop through all of the parameters we'll build. When T is
12206 a function parameter pack, LEN is the number of expanded
12207 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12210 {
12217 /* We're on the Ith parameter of the function parameter
12218 pack. */
12219 {
12220 /* Get the Ith type. */
12223 /* Rename the parameter to include the index. */
12226 }
12228 /* We're dealing with a normal parameter. */
12236 {
12239 else
12242 }
12252 /* Keep track of the first new parameter we
12253 generate. That's what will be returned to the
12254 caller. */
12258 /* Build a proper chain of parameters when substituting
12259 into a function parameter pack. */
12262 }
12264 /* If cp_unevaluated_operand is set, we're just looking for a
12265 single dummy parameter, so don't keep going. */
12270 /* FIRST_R contains the start of the chain we've built. */
12272 }
12276 {
12283 {
12284 /* This field is a lambda capture pack. Return a TREE_VEC of
12285 the expanded fields to instantiate_class_template_1 and
12286 store them in the specializations hash table as a
12287 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12291 {
12294 }
12295 else
12296 {
12297 /* All we did was update the type. Make a note of that. */
12300 }
12301 }
12304 {
12307 {
12311 }
12321 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12322 non-bit-fields DECL_INITIAL is a non-static data member
12323 initializer, which gets deferred instantiation. */
12329 {
12330 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12331 NSDMI in perform_member_init. Still set DECL_INITIAL
12332 so that we know there is one. */
12337 }
12338 /* We don't have to set DECL_CONTEXT here; it is set by
12339 finish_member_declaration. */
12347 }
12350 {
12358 }
12359 }
12363 /* We reach here only for member using decls. We also need to check
12364 uses_template_parms because DECL_DEPENDENT_P is not set for a
12365 using-declaration that designates a member of the current
12366 instantiation (c++/53549). */
12369 {
12376 else
12377 {
12380 }
12381 }
12382 else
12383 {
12386 }
12391 {
12394 tree spec;
12396 tree ctx;
12405 {
12406 /* If this is the canonical decl, we don't have to
12407 mess with instantiations, and often we can't (for
12408 typename, template type parms and such). Note that
12409 TYPE_NAME is not correct for the above test if
12410 we've copied the type for a typedef. */
12416 }
12418 /* Check to see if we already have the specialization we
12419 need. */
12422 {
12423 /* T is a static data member or namespace-scope entity.
12424 We have to substitute into namespace-scope variables
12425 (not just variable templates) because of cases like:
12427 template <class T> void f() { extern T t; }
12429 where the entity referenced is not known until
12430 instantiation time. */
12434 {
12436 complain,
12438 /* If CTX is unchanged, then T is in fact the
12439 specialization we want. That situation occurs when
12440 referencing a static data member within in its own
12441 class. We can use pointer equality, rather than
12442 same_type_p, because DECL_CONTEXT is always
12443 canonical... */
12445 /* ... unless T is a member template; in which
12446 case our caller can be willing to create a
12447 specialization of that template represented
12448 by T. */
12452 }
12455 {
12460 argvec = (coerce_innermost_template_parms
12468 }
12469 }
12470 else
12471 {
12472 /* A local variable. */
12474 /* Subsequent calls to pushdecl will fill this in. */
12476 /* Unless this is a reference to a static variable from an
12477 enclosing function, in which case we need to fill it in now. */
12479 {
12483 }
12485 }
12486 /* If we already have the specialization we need, there is
12487 nothing more to do. */
12489 {
12492 }
12494 /* Create a new node for the specialization we need. */
12497 {
12500 else
12507 }
12509 {
12510 /* Even if the original location is out of scope, the
12511 newly substituted one is not. */
12518 {
12519 /* It may seem that this case cannot occur, since:
12521 typedef void f();
12522 void g() { f x; }
12524 declares a function, not a variable. However:
12526 typedef void f();
12527 template <typename T> void g() { T t; }
12528 template void g<f>();
12530 is an attempt to declare a variable with function
12531 type. */
12533 /* R is not yet sufficiently initialized, so we
12534 just use its name. */
12537 }
12539 /* Wait until cp_finish_decl to set this again, to handle
12540 circular dependency (template/instantiate6.C). */
12545 {
12550 {
12553 }
12555 }
12559 }
12565 /* Clear out the mangled name and RTL for the instantiation. */
12569 /* The initializer must not be expanded until it is required;
12570 see [temp.inst]. */
12578 {
12579 /* Possibly limit visibility based on template args. */
12582 {
12586 }
12588 }
12591 {
12592 /* A static data member declaration is always marked
12593 external when it is declared in-class, even if an
12594 initializer is present. We mimic the non-template
12595 processing here. */
12603 }
12604 else
12605 {
12610 }
12618 /* Preserve a typedef that names a type. */
12620 {
12624 /* An alias template specialization can be dependent
12625 even if its underlying type is not. */
12627 }
12630 }
12635 }
12636 #undef RETURN
12638 out:
12639 /* Restore the file and line information. */
12643 }
12645 /* Substitute into the ARG_TYPES of a function type.
12646 If END is a TREE_CHAIN, leave it and any following types
12647 un-substituted. */
12649 static tree
12651 tree args,
12652 tree end,
12653 tsubst_flags_t complain,
12654 tree in_decl)
12655 {
12656 tree remaining_arg_types;
12660 tree default_arg;
12671 {
12672 /* For a pack expansion, perform substitution on the
12673 entire expression. Later on, we'll handle the arguments
12674 one-by-one. */
12679 /* So that we'll spin through the parameters, one by one. */
12681 else
12682 {
12683 /* We only partially substituted into the parameter
12684 pack. Our type is TYPE_PACK_EXPANSION. */
12687 }
12688 }
12701 {
12703 {
12707 }
12709 }
12710 /* DR 657. */
12714 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12715 top-level qualifiers as required. */
12718 /* We do not substitute into default arguments here. The standard
12719 mandates that they be instantiated only when needed, which is
12720 done in build_over_call. */
12724 {
12725 /* We've instantiated a template before its default arguments
12726 have been parsed. This can happen for a nested template
12727 class, and is not an error unless we require the default
12728 argument in a call of this function. */
12729 remaining_arg_types =
12732 }
12733 else
12734 remaining_arg_types =
12736 }
12739 }
12741 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12742 *not* handle the exception-specification for FNTYPE, because the
12743 initial substitution of explicitly provided template parameters
12744 during argument deduction forbids substitution into the
12745 exception-specification:
12747 [temp.deduct]
12749 All references in the function type of the function template to the
12750 corresponding template parameters are replaced by the specified tem-
12751 plate argument values. If a substitution in a template parameter or
12752 in the function type of the function template results in an invalid
12753 type, type deduction fails. [Note: The equivalent substitution in
12754 exception specifications is done only when the function is instanti-
12755 ated, at which point a program is ill-formed if the substitution
12756 results in an invalid type.] */
12758 static tree
12760 tree args,
12761 tsubst_flags_t complain,
12762 tree in_decl)
12763 {
12764 tree return_type;
12766 tree fntype;
12768 /* The TYPE_CONTEXT is not used for function/method types. */
12771 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12772 failure. */
12776 {
12777 /* Substitute the argument types. */
12789 {
12790 /* DR 1207: 'this' is in scope in the trailing return type. */
12792 }
12794 /* Substitute the return type. */
12798 {
12801 }
12802 }
12803 else
12804 /* Substitute the return type. */
12809 /* DR 486 clarifies that creation of a function type with an
12810 invalid return type is a deduction failure. */
12813 {
12815 {
12818 else
12820 }
12822 }
12823 /* And DR 657. */
12828 {
12829 /* Substitute the argument types. */
12834 }
12836 /* Construct a new type node and return it. */
12838 {
12843 }
12844 else
12845 {
12847 /* Don't pick up extra function qualifiers from the basetype. */
12850 {
12851 /* [temp.deduct]
12853 Type deduction may fail for any of the following
12854 reasons:
12856 -- Attempting to create "pointer to member of T" when T
12857 is not a class type. */
12860 r);
12862 }
12867 }
12874 }
12876 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12877 ARGS into that specification, and return the substituted
12878 specification. If there is no specification, return NULL_TREE. */
12880 static tree
12882 tree args,
12883 tsubst_flags_t complain,
12884 tree in_decl,
12886 {
12887 tree specs;
12888 tree new_specs;
12893 {
12894 /* A noexcept-specifier. */
12899 {
12900 /* Defer instantiation of noexcept-specifiers to avoid
12901 excessive instantiations (c++/49107). */
12904 {
12905 /* We already partially instantiated this member template,
12906 so combine the new args with the old. */
12911 }
12912 else
12913 {
12916 }
12917 }
12918 else
12919 new_specs = tsubst_copy_and_build
12923 }
12925 {
12928 else
12930 {
12931 tree spec;
12936 {
12937 /* Expand the pack expansion type. */
12940 in_decl);
12946 else
12947 {
12948 /* We're substituting into a member template, so
12949 we got a TYPE_PACK_EXPANSION back. Add that
12950 expansion and move on. */
12954 expanded_specs,
12955 complain);
12958 }
12959 }
12962 {
12965 else
12970 complain);
12971 }
12974 }
12975 }
12977 }
12979 /* Take the tree structure T and replace template parameters used
12980 therein with the argument vector ARGS. IN_DECL is an associated
12981 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12982 Issue error and warning messages under control of COMPLAIN. Note
12983 that we must be relatively non-tolerant of extensions here, in
12984 order to preserve conformance; if we allow substitutions that
12985 should not be allowed, we may allow argument deductions that should
12986 not succeed, and therefore report ambiguous overload situations
12987 where there are none. In theory, we could allow the substitution,
12988 but indicate that it should have failed, and allow our caller to
12989 make sure that the right thing happens, but we don't try to do this
12990 yet.
12992 This function is used for dealing with types, decls and the like;
12993 for expressions, use tsubst_expr or tsubst_copy. */
12995 tree
12997 {
13020 else
13025 /* Reuse typedefs. We need to do this to handle dependent attributes,
13026 such as attribute aligned. */
13029 {
13033 {
13034 /* DECL represents an alias template and we want to
13035 instantiate it. */
13039 }
13043 {
13047 }
13052 else
13053 /* The typedef is from a non-template context. */
13057 {
13059 r = cp_build_qualified_type_real
13063 }
13064 else
13065 {
13066 /* We don't have an instantiation yet, so drop the typedef. */
13071 }
13072 }
13088 {
13114 {
13120 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13121 needed. */
13127 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13128 with TREE_SIDE_EFFECTS that indicates this is not an integral
13129 constant expression. */
13132 {
13135 }
13138 }
13144 {
13150 /* Early in template argument deduction substitution, we don't
13151 want to reduce the level of 'auto', or it will be confused
13152 with a normal template parm in subsequent deduction. */
13164 {
13168 {
13169 /* See through ARGUMENT_PACK_SELECT arguments. */
13171 /* If the selected argument is an expansion E, that most
13172 likely means we were called from
13173 gen_elem_of_pack_expansion_instantiation during the
13174 substituting of pack an argument pack (which Ith
13175 element is a pack expansion, where I is
13176 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13177 In this case, the Ith element resulting from this
13178 substituting is going to be a pack expansion, which
13179 pattern is the pattern of E. Let's return the
13180 pattern of E, and
13181 gen_elem_of_pack_expansion_instantiation will
13182 build the resulting pack expansion from it. */
13184 {
13185 /* Make sure we aren't throwing away arg info. */
13188 }
13189 }
13190 }
13195 {
13197 /* If ARG is an argument pack, we don't actually want to
13198 perform a substitution here, because substitutions
13199 for argument packs are only done
13200 element-by-element. We can get to this point when
13201 substituting the type of a non-type template
13202 parameter pack, when that type actually contains
13203 template parameter packs from an outer template, e.g.,
13205 template<typename... Types> struct A {
13206 template<Types... Values> struct B { };
13207 }; */
13211 {
13217 return cp_build_qualified_type_real
13219 }
13221 {
13222 /* We are processing a type constructed from a
13223 template template parameter. */
13234 /* Consider this code:
13236 template <template <class> class Template>
13237 struct Internal {
13238 template <class Arg> using Bind = Template<Arg>;
13239 };
13241 template <template <class> class Template, class Arg>
13242 using Instantiate = Template<Arg>; //#0
13244 template <template <class> class Template,
13245 class Argument>
13246 using Bind =
13247 Instantiate<Internal<Template>::template Bind,
13248 Argument>; //#1
13250 When #1 is parsed, the
13251 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13252 parameter `Template' in #0 matches the
13253 UNBOUND_CLASS_TEMPLATE representing the argument
13254 `Internal<Template>::template Bind'; We then want
13255 to assemble the type `Bind<Argument>' that can't
13256 be fully created right now, because
13257 `Internal<Template>' not being complete, the Bind
13258 template cannot be looked up in that context. So
13259 we need to "store" `Bind<Argument>' for later
13260 when the context of Bind becomes complete. Let's
13261 store that in a TYPENAME_TYPE. */
13265 argvec),
13266 typename_type,
13267 complain);
13269 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13270 are resolving nested-types in the signature of a
13271 member function templates. Otherwise ARG is a
13272 TEMPLATE_DECL and is the real template to be
13273 instantiated. */
13281 complain);
13282 return cp_build_qualified_type_real
13284 }
13287 else
13288 /* TEMPLATE_PARM_INDEX. */
13290 }
13293 /* This can happen during the attempted tsubst'ing in
13294 unify. This means that we don't yet have any information
13295 about the template parameter in question. */
13298 /* If we get here, we must have been looking at a parm for a
13299 more deeply nested template. Make a new version of this
13300 template parameter, but with a lower level. */
13302 {
13307 {
13309 r = cp_build_qualified_type_real
13313 }
13320 /* Break infinite recursion when substituting the constraints
13322 else
13323 {
13334 {
13335 /* Propagate constraints on placeholders. */
13340 {
13344 }
13345 }
13348 /* We have reduced the level of the template
13349 template parameter, but not the levels of its
13350 template parameters, so canonical_type_parameter
13351 will not be able to find the canonical template
13352 template parameter for this level. Thus, we
13353 require structural equality checking to compare
13354 TEMPLATE_TEMPLATE_PARMs. */
13358 else
13362 {
13364 /* We might need to substitute into the types of non-type
13365 template parameters. */
13377 }
13378 }
13387 }
13390 }
13393 {
13401 {
13405 }
13408 {
13412 }
13415 {
13419 }
13425 }
13428 /* We should never be tsubsting a binfo. */
13432 /* A vector of template arguments. */
13438 {
13442 /* [temp.deduct]
13444 Type deduction may fail for any of the following
13445 reasons:
13447 -- Attempting to create a pointer to reference type.
13448 -- Attempting to create a reference to a reference type or
13449 a reference to void.
13451 Core issue 106 says that creating a reference to a reference
13452 during instantiation is no longer a cause for failure. We
13453 only enforce this check in strict C++98 mode. */
13457 {
13460 /* We keep track of the last time we issued this error
13461 message to avoid spewing a ton of messages during a
13462 single bad template instantiation. */
13465 {
13470 else
13473 }
13476 }
13480 {
13482 {
13485 type);
13486 else
13488 type);
13489 }
13491 }
13493 {
13497 }
13499 /* In C++0x, during template argument substitution, when there is an
13500 attempt to create a reference to a reference type, reference
13501 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13503 "If a template-argument for a template-parameter T names a type
13504 that is a reference to a type A, an attempt to create the type
13505 'lvalue reference to cv T' creates the type 'lvalue reference to
13506 A,' while an attempt to create the type type rvalue reference to
13507 cv T' creates the type T"
13508 */
13509 r = cp_build_reference_type
13512 else
13517 /* Will this ever be needed for TYPE_..._TO values? */
13521 }
13523 {
13526 {
13527 /* [temp.deduct]
13529 Type deduction may fail for any of the following
13530 reasons:
13532 -- Attempting to create "pointer to member of T" when T
13533 is not a class type. */
13537 }
13539 {
13543 }
13545 {
13549 }
13552 {
13553 /* The type of the implicit object parameter gets its
13554 cv-qualifiers from the FUNCTION_TYPE. */
13555 tree memptr;
13556 tree method_type
13561 complain);
13562 }
13563 else
13566 complain);
13567 }
13570 {
13571 tree fntype;
13572 tree specs;
13577 /* Substitute the exception specification. */
13585 }
13587 {
13592 /* As an optimization, we avoid regenerating the array type if
13593 it will obviously be the same as T. */
13597 /* These checks should match the ones in create_array_type_for_decl.
13599 [temp.deduct]
13601 The deduction may fail for any of the following reasons:
13603 -- Attempting to create an array with an element type that
13604 is void, a function type, or a reference type, or [DR337]
13605 an abstract class type. */
13611 {
13615 }
13623 {
13626 }
13629 }
13632 {
13644 {
13648 }
13650 {
13651 /* Normally, make_typename_type does not require that the CTX
13652 have complete type in order to allow things like:
13654 template <class T> struct S { typename S<T>::X Y; };
13656 But, such constructs have already been resolved by this
13657 point, so here CTX really should have complete type, unless
13658 it's a partial instantiation. */
13661 {
13665 }
13666 }
13673 {
13676 }
13679 {
13681 {
13685 else
13687 }
13689 {
13693 else
13695 }
13696 }
13698 return cp_build_qualified_type_real
13700 }
13703 {
13715 }
13718 {
13719 tree type;
13735 complain);
13736 }
13739 {
13740 tree type;
13751 {
13753 {
13757 }
13760 }
13770 else
13771 {
13775 /* In a template ~id could be either a complement expression
13776 or an unqualified-id naming a destructor; if instantiating
13777 it produces an expression, it's not an id-expression or
13778 member access. */
13781 }
13786 }
13789 {
13793 }
13797 {
13798 tree r;
13801 {
13803 /* Set the already-substituted type. */
13805 }
13806 else
13814 }
13829 /* We should use one of the expression tsubsts for these codes. */
13835 }
13836 }
13838 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13839 type of the expression on the left-hand side of the "." or "->"
13840 operator. */
13842 static tree
13845 {
13846 tree name;
13847 tree qualifying_scope;
13848 tree fns;
13849 tree optype;
13854 /* A baselink indicates a function from a base class. Both the
13855 BASELINK_ACCESS_BINFO and the base class referenced may
13856 indicate bases of the template class, rather than the
13857 instantiated class. In addition, lookups that were not
13858 ambiguous before may be ambiguous now. Therefore, we perform
13859 the lookup again. */
13866 {
13873 }
13879 {
13881 {
13885 }
13887 }
13889 /* If lookup found a single function, mark it as used at this
13890 point. (If it lookup found multiple functions the one selected
13891 later by overload resolution will be marked as used at that
13892 point.) */
13899 /* Add back the template arguments, if present. */
13903 unknown_type_node,
13905 template_args);
13906 /* Update the conversion operator type. */
13914 {
13916 qualifying_scope,
13917 object_type);
13919 /* We need to call adjust_result_of_qualified_name_lookup in case the
13920 destructor names a base class, but we unset BASELINK_QUALIFIED_P
13921 so that we still get virtual function binding. */
13923 }
13925 }
13927 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13928 true if the qualified-id will be a postfix-expression in-and-of
13929 itself; false if more of the postfix-expression follows the
13930 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13931 of "&". */
13933 static tree
13937 {
13938 tree expr;
13939 tree scope;
13940 tree name;
13942 tree template_args;
13947 /* Figure out what name to look up. */
13950 {
13960 }
13961 else
13962 {
13965 }
13967 /* Substitute into the qualifying scope. When there are no ARGS, we
13968 are just trying to simplify a non-dependent expression. In that
13969 case the qualifying scope may be dependent, and, in any case,
13970 substituting will not help. */
13973 {
13976 }
13977 else
13981 {
13988 }
13991 {
13993 {
13994 /* A BIT_NOT_EXPR is used to represent a destructor. */
13996 {
14000 }
14001 else
14004 }
14005 else
14009 {
14011 {
14015 }
14017 }
14018 }
14021 {
14023 scope);
14024 /* Remember that there was a reference to this entity. */
14027 }
14030 {
14036 }
14039 {
14042 complain);
14043 else
14045 }
14051 {
14052 expr = (adjust_result_of_qualified_name_lookup
14054 expr = (finish_qualified_id_expr
14058 }
14060 /* Expressions do not generally have reference type. */
14062 /* However, if we're about to form a pointer-to-member, we just
14063 want the referenced member referenced. */
14071 }
14073 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14074 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14075 for tsubst. */
14077 static tree
14080 {
14087 {
14088 /* If we had an initializer but it
14089 instantiated to nothing,
14090 value-initialize the object. This will
14091 only occur when the initializer was a
14092 pack expansion where the parameter packs
14093 used in that expansion were of length
14094 zero. */
14096 complain);
14099 }
14102 }
14104 /* Like tsubst, but deals with expressions. This function just replaces
14105 template parms; to finish processing the resultant expression, use
14106 tsubst_copy_and_build or tsubst_expr. */
14108 static tree
14110 {
14112 tree r;
14120 {
14125 {
14126 /* We get here for a use of 'this' in an NSDMI as part of a
14127 constructor call or as part of an aggregate initialization. */
14129 && ((current_function_decl
14131 || (current_class_ref
14135 /* This can happen for a parameter name used later in a function
14136 declaration (such as in a late-specified return type). Just
14137 make a dummy decl, since it's only used for its type. */
14140 /* Give it the template pattern as its context; its true context
14141 hasn't been instantiated yet and this is good enough for
14142 mangling. */
14144 }
14153 {
14154 tree enum_type;
14155 tree v;
14159 /* There is no need to substitute into namespace-scope
14160 enumerators. */
14163 /* If ARGS is NULL, then T is known to be non-dependent. */
14167 /* Unfortunately, we cannot just call lookup_name here.
14168 Consider:
14170 template <int I> int f() {
14171 enum E { a = I };
14172 struct S { void g() { E e = a; } };
14173 };
14175 When we instantiate f<7>::S::g(), say, lookup_name is not
14176 clever enough to find f<7>::a. */
14177 enum_type
14187 /* We didn't find the name. That should never happen; if
14188 name-lookup found it during preliminary parsing, we
14189 should find it again here during instantiation. */
14191 }
14196 {
14197 /* Check for a local specialization set up by
14198 tsubst_pack_expansion. */
14200 {
14204 }
14206 /* When retrieving a capture pack from a generic lambda, remove the
14207 lambda call op's own template argument list from ARGS. Only the
14208 template arguments active for the closure type should be used to
14209 retrieve the pack specialization. */
14215 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14216 tsubst_decl put in the hash table. */
14218 }
14221 {
14222 tree ctx;
14227 {
14230 {
14234 }
14236 }
14237 }
14247 {
14250 {
14251 /* First try name lookup to find the instantiation. */
14254 {
14255 /* Make sure that the one we found is the one we want. */
14261 }
14265 else
14266 {
14267 /* This can happen for a variable used in a
14268 late-specified return type of a local lambda, or for a
14269 local static or constant. Building a new VAR_DECL
14270 should be OK in all those cases. */
14273 {
14274 /* We can't call cp_finish_decl, so handle the
14275 initializer by hand. */
14286 }
14293 }
14294 /* Remember this for subsequent uses. */
14297 }
14298 }
14299 else
14309 /* An OVERLOAD will always be a non-dependent overload set; an
14310 overload set from function scope will just be represented with an
14311 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14327 {
14328 /* Template template argument like the following example need
14329 special treatment:
14331 template <template <class> class TT> struct C {};
14332 template <class T> struct D {
14333 template <class U> struct E {};
14334 C<E> c; // #1
14335 };
14336 D<int> d; // #2
14338 We are processing the template argument `E' in #1 for
14339 the template instantiation #2. Originally, `E' is a
14340 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14341 have to substitute this with one having context `D<int>'. */
14345 }
14346 else
14347 /* Ordinary template template argument. */
14358 {
14362 }
14367 {
14376 /* We only want to compute the number of arguments. */
14379 else
14386 {
14388 /* Set TREE_USED for the benefit of -Wunused. */
14392 }
14400 {
14405 else
14411 else
14414 }
14415 else
14417 }
14419 {
14427 }
14428 /* Fall through */
14444 {
14448 }
14451 {
14452 tree object;
14453 tree name;
14458 {
14462 }
14465 {
14475 }
14480 in_decl);
14481 else
14484 }
14522 {
14526 }
14529 {
14534 }
14537 {
14541 }
14544 {
14552 }
14558 {
14565 }
14568 {
14575 }
14578 {
14585 }
14588 {
14589 /* Substituted template arguments */
14598 }
14601 {
14621 }
14646 /* Fall through. */
14649 {
14652 }
14653 else
14657 /* This is handled by tsubst_copy_and_build. */
14661 {
14665 }
14668 /* We shouldn't have built any of these during initial template
14669 generation. Instead, they should be built during instantiation
14670 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14674 {
14684 }
14702 {
14703 /* Instantiate any typedefs in the type. */
14708 }
14711 /* These can sometimes show up in a partial instantiation, but never
14712 involve template parms. */
14726 /* We shouldn't get here, but keep going if !flag_checking. */
14730 }
14731 }
14733 /* Helper function for tsubst_omp_clauses, used for instantiation of
14734 OMP_CLAUSE_DECL of clauses. */
14736 static tree
14738 tree in_decl)
14739 {
14743 /* Handle an OpenMP array section represented as a TREE_LIST (or
14744 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
14745 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
14746 TREE_LIST. We can handle it exactly the same as an array section
14747 (purpose, value, and a chain), even though the nomenclature
14748 (low_bound, length, etc) is different. */
14750 {
14751 tree low_bound
14757 in_decl);
14766 }
14769 /* Undo convert_from_reference tsubst_expr could have called. */
14775 }
14777 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14779 static tree
14782 {
14787 {
14793 {
14796 {
14802 }
14803 /* FALLTHRU */
14818 in_decl);
14849 {
14852 {
14859 }
14860 else
14862 }
14865 in_decl);
14871 in_decl);
14879 in_decl);
14881 {
14884 }
14889 else
14892 in_decl,
14915 {
14919 loc;
14921 {
14924 }
14925 }
14929 }
14932 {
14942 /* tsubst_expr on SCOPE_REF results in returning
14943 finish_non_static_data_member result. Undo that here. */
14947 {
14952 {
14956 CASE_CONVERT:
14965 /* FALLTHRU */
14969 }
14970 }
14976 {
14979 {
14983 }
14984 }
14988 }
14989 }
14993 {
14998 {
15001 }
15002 }
15004 }
15006 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15008 static tree
15010 tree in_decl)
15011 {
15012 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15032 {
15035 else
15036 {
15040 }
15041 }
15046 #undef RECUR
15047 }
15049 /* Used to temporarily communicate the list of #pragma omp parallel
15050 clauses to #pragma omp for instantiation if they are combined
15051 together. */
15055 /* Substitute one OMP_FOR iterator. */
15057 static void
15062 {
15063 #define RECUR(NODE) \
15064 tsubst_expr ((NODE), args, complain, in_decl, \
15065 integral_constant_expression_p)
15072 {
15075 }
15081 {
15082 /* We need to jump through some hoops to handle declarations in the
15083 init-statement, since we might need to handle auto deduction,
15084 but we need to keep control of initialization. */
15088 }
15089 else
15090 {
15092 {
15095 {
15099 {
15103 CASE_CONVERT:
15111 {
15114 }
15115 /* FALLTHRU */
15119 }
15120 }
15121 }
15122 else
15124 }
15135 {
15137 {
15138 /* Declare the variable, but don't let that initialize it. */
15143 }
15148 {
15153 }
15154 else
15161 }
15164 {
15165 /* Declare and initialize the variable. */
15168 }
15170 {
15174 {
15176 {
15182 {
15185 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15190 }
15193 {
15195 decl);
15197 }
15200 {
15202 decl);
15204 }
15205 else
15207 }
15210 }
15212 {
15217 {
15220 }
15221 }
15222 }
15225 {
15229 }
15230 else
15234 {
15245 {
15253 }
15254 else
15260 {
15266 }
15270 {
15278 }
15279 else
15285 }
15291 #undef RECUR
15292 }
15294 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15295 of OMP_TARGET's body. */
15297 static tree
15299 {
15302 {
15311 }
15313 }
15315 /* Helper function for tsubst_expr. For decomposition declaration
15316 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15317 also the corresponding decls representing the identifiers
15318 of the decomposition declaration. Return DECL if successful
15319 or error_mark_node otherwise, set *FIRST to the first decl
15320 in the list chained through DECL_CHAIN and *CNT to the number
15321 of such decls. */
15323 static tree
15327 {
15332 decl2
15337 {
15353 {
15356 }
15357 else
15359 }
15362 }
15364 /* Like tsubst_copy for expressions, etc. but also does semantic
15365 processing. */
15367 tree
15370 {
15371 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15372 #define RECUR(NODE) \
15373 tsubst_expr ((NODE), args, complain, in_decl, \
15374 integral_constant_expression_p)
15377 tree r;
15378 location_t loc;
15390 {
15392 {
15393 tree_stmt_iterator i;
15397 }
15412 else
15421 {
15423 tree init;
15429 {
15439 else
15441 }
15443 {
15444 /* Don't build up decls for a variadic capture proxy, we'll
15445 instantiate the elements directly as needed. */
15447 }
15448 else
15449 {
15453 {
15454 /* By marking the declaration as instantiated, we avoid
15455 trying to instantiate it. Since instantiate_decl can't
15456 handle local variables, and since we've already done
15457 all that needs to be done, that's the right thing to
15458 do. */
15463 /* Anonymous aggregates are a special case. */
15466 {
15469 {
15473 }
15475 }
15481 {
15486 }
15487 else
15488 {
15493 {
15494 /* For __PRETTY_FUNCTION__ we have to adjust the
15495 initializer. */
15499 }
15500 else
15504 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15508 {
15510 tree first;
15516 }
15517 }
15518 }
15519 }
15522 }
15537 {
15545 {
15547 tree first;
15552 }
15553 else
15558 }
15584 else
15585 {
15592 }
15598 {
15607 }
15615 else
15623 else
15644 {
15651 }
15655 {
15657 tree label;
15664 }
15670 /* Computed goto's must be tsubst'd into. On the other hand,
15671 non-computed gotos must not be; the identifier in question
15672 will have no binding. */
15674 else
15680 {
15696 }
15701 {
15706 }
15707 else
15708 {
15713 else
15720 else
15726 else
15728 }
15732 {
15736 {
15738 /* Prevent instantiate_decl from trying to instantiate
15739 this variable. We've already done all that needs to be
15740 done. */
15743 }
15748 }
15754 {
15755 /* Local classes are not independent templates; they are
15756 instantiated along with their containing function. And this
15757 way we don't have to deal with pushing out of one local class
15758 to instantiate a member of another local class. */
15759 tree fn;
15760 /* Closures are handled by the LAMBDA_EXPR. */
15766 }
15770 {
15771 tree condition;
15774 condition =
15776 args,
15785 }
15791 in_decl);
15828 {
15843 in_decl);
15845 {
15852 }
15864 integral_constant_expression_p);
15875 else
15876 {
15884 }
15888 }
15893 /* FALLTHRU */
15900 in_decl);
15917 in_decl);
15928 {
15931 {
15932 /* For combined target teams, ensure the num_teams and
15933 thread_limit clause expressions are evaluated on the host,
15934 before entering the target construct. */
15935 tree c;
15941 {
15950 OMP_CLAUSE_FIRSTPRIVATE);
15954 }
15955 }
15956 }
16016 {
16021 {
16024 }
16030 }
16031 else
16032 {
16039 {
16042 }
16045 {
16050 {
16053 }
16059 }
16060 else
16061 {
16065 }
16068 }
16072 {
16078 {
16082 {
16087 }
16091 }
16092 else
16093 {
16098 }
16099 }
16103 {
16107 }
16127 /* If the first operand was a statement, we're done with it. */
16131 complain));
16143 integral_constant_expression_p));
16144 }
16147 out:
16150 #undef RECUR
16151 #undef RETURN
16152 }
16154 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16155 function. For description of the body see comment above
16156 cp_parser_omp_declare_reduction_exprs. */
16158 static void
16160 {
16166 tree_stmt_iterator tsi;
16177 {
16196 }
16198 {
16218 }
16219 }
16221 /* T is a postfix-expression that is not being used in a function
16222 call. Return the substituted version of T. */
16224 static tree
16226 tsubst_flags_t complain,
16227 tree in_decl)
16228 {
16232 else
16238 }
16240 /* Like tsubst but deals with expressions and performs semantic
16241 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16243 tree
16245 tree args,
16246 tsubst_flags_t complain,
16247 tree in_decl,
16250 {
16251 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16252 #define RECUR(NODE) \
16253 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16255 integral_constant_expression_p)
16258 location_t loc;
16267 /* N3276 decltype magic only applies to calls at the top level or on the
16268 right side of a comma. */
16273 {
16276 /* Fall through. */
16278 {
16279 tree decl;
16280 cp_id_kind idk;
16285 {
16288 }
16290 /* Look up the name. */
16293 /* By convention, expressions use ERROR_MARK_NODE to indicate
16294 failure, not NULL_TREE. */
16300 integral_constant_expression_p,
16308 input_location);
16312 {
16316 }
16318 }
16321 {
16322 tree object;
16335 {
16338 }
16339 else
16346 else
16348 }
16351 {
16355 {
16356 /* A type conversion to reference type will be enclosed in
16357 such an indirect ref, but the substitution of the cast
16358 will have also added such an indirect ref. */
16361 }
16362 else
16370 }
16373 {
16377 }
16380 {
16387 flags));
16388 }
16391 {
16395 }
16402 {
16403 tree type;
16409 {
16414 }
16420 {
16438 }
16441 }
16475 else
16477 in_decl);
16512 {
16519 tree r = build_x_binary_op
16521 op0,
16523 ? ERROR_MARK
16525 op1,
16527 ? ERROR_MARK
16535 }
16538 {
16542 }
16555 {
16564 }
16569 /* Fall through */
16572 {
16573 tree r;
16579 {
16580 /* When there are no ARGS, we are trying to evaluate a
16581 non-dependent expression from the parser. Trying to do
16582 the substitutions may not work. */
16585 }
16586 else
16587 {
16592 else
16595 /*integral_constant_expression_p=*/
16599 }
16603 else
16607 {
16609 {
16611 {
16615 }
16616 else
16620 }
16622 }
16624 }
16627 {
16637 }
16653 {
16657 tree r = build_x_modify_expr
16660 /* TREE_NO_WARNING must be set if either the expression was
16661 parenthesized or it uses an operator such as >>= rather
16662 than plain assignment. In the former case, it was already
16663 set and must be copied. In the latter case,
16664 build_x_modify_expr sets it and it must not be reset
16665 here. */
16670 }
16675 /* Remember that there was a reference to this entity. */
16682 {
16687 tree ret;
16691 else
16692 {
16696 }
16698 /* If there was an initializer in the original tree, but it
16699 instantiated to an empty list, then we should pass a
16700 non-NULL empty vector to tell build_new that it was an
16701 empty initializer() rather than no initializer. This can
16702 only happen when the initializer is a pack expansion whose
16703 parameter packs are of length zero. */
16706 else
16707 {
16711 else
16712 {
16715 }
16716 }
16722 complain);
16730 }
16733 {
16739 complain));
16740 }
16743 {
16747 integral_constant_expression_p);
16749 op0,
16752 }
16755 {
16756 tree function;
16761 tree ret;
16764 /* Internal function with no arguments. */
16768 /* When we parsed the expression, we determined whether or
16769 not Koenig lookup should be performed. */
16772 {
16775 }
16777 {
16782 }
16784 {
16785 /* Do nothing; calling tsubst_copy_and_build on an identifier
16786 would incorrectly perform unqualified lookup again.
16788 Note that we can also have an IDENTIFIER_NODE if the earlier
16789 unqualified lookup found a member function; in that case
16790 koenig_p will be false and we do want to do the lookup
16791 again to find the instantiated member function.
16793 FIXME but doing that causes c++/15272, so we need to stop
16794 using IDENTIFIER_NODE in that situation. */
16796 }
16797 else
16798 {
16800 {
16806 }
16807 else
16812 /* Avoid error about taking the address of a constructor. */
16816 in_decl,
16818 integral_constant_expression_p);
16822 }
16827 {
16832 else
16833 {
16834 /* Expand the pack expansion and push each entry onto
16835 CALL_ARGS. */
16838 {
16843 {
16848 }
16849 }
16850 else
16851 {
16852 /* A partial substitution. Add one entry. */
16854 }
16855 }
16856 }
16858 /* We do not perform argument-dependent lookup if normal
16859 lookup finds a non-function, in accordance with the
16860 expected resolution of DR 218. */
16863 /* If lookup found a member function, the Koenig lookup is
16864 not appropriate, even if an unqualified-name was used
16865 to denote the function. */
16868 /* Only do this when substitution turns a dependent call
16869 into a non-dependent call. */
16877 {
16879 {
16880 /* For backwards compatibility and good diagnostics, try
16881 the unqualified lookup again if we aren't in SFINAE
16882 context. */
16883 tree unq = (tsubst_copy_and_build
16885 integral_constant_expression_p));
16887 {
16890 }
16893 {
16902 "%qD was not declared in this scope, "
16903 "and no declarations were found by "
16904 "argument-dependent lookup at the point "
16906 {
16910 {
16912 input_location);
16914 "declarations in dependent base %qT are "
16920 else
16924 }
16925 else
16927 "%qD declared here, later in the "
16929 }
16931 }
16932 }
16934 {
16939 }
16940 }
16942 /* Remember that there was a reference to this entity. */
16946 {
16949 }
16951 /* Put back tf_decltype for the actual call. */
16956 {
16960 {
16962 "wrong number of arguments to "
16965 }
16966 else
16968 input_location),
16973 /* Unsupported internal function with arguments. */
16975 }
16978 complain);
16980 {
16995 complain);
16996 else
16997 ret = (build_new_method_call
17002 complain));
17003 }
17004 else
17007 koenig_p,
17008 complain);
17013 {
17019 {
17025 {
17027 /* The thunk location is not interesting. */
17029 }
17030 }
17031 }
17034 }
17037 {
17043 {
17045 {
17050 }
17051 else
17052 {
17057 }
17059 }
17060 else
17061 {
17064 }
17068 }
17071 {
17076 input_location));
17077 }
17080 {
17088 {
17089 /* We have pack expansions, so expand those and
17090 create a new list out of it. */
17093 tree chain;
17096 /* Expand the argument expressions. */
17104 /* Build the rest of the list. */
17109 /* Determine the number of arguments. */
17111 {
17114 }
17117 else
17118 {
17119 /* Since we only performed a partial substitution into
17120 the argument pack, we only RETURN (a single list
17121 node. */
17128 }
17130 /* Convert the argument vectors into a TREE_LIST */
17133 {
17134 /* Grab the Ith values. */
17135 i--;
17138 value
17142 /* Build the list (backwards). */
17144 }
17147 }
17163 }
17166 {
17167 tree object;
17168 tree object_type;
17169 tree member;
17170 tree r;
17174 /* Remember that there was a reference to this entity. */
17185 else
17193 {
17195 {
17200 {
17203 }
17205 {
17210 }
17211 }
17212 }
17215 {
17216 /* Lookup the template functions now that we know what the
17217 scope is. */
17225 {
17228 args);
17229 member = (adjust_result_of_qualified_name_lookup
17231 object_type));
17232 }
17233 else
17234 {
17236 input_location);
17238 }
17239 }
17243 {
17245 {
17249 else
17252 }
17254 }
17256 {
17261 }
17265 complain);
17269 }
17276 {
17284 tree r;
17289 /* digest_init will do the wrong thing if we let it. */
17293 /* We do not want to process the index of aggregate
17294 initializers as they are identifier nodes which will be
17295 looked up by digest_init. */
17301 {
17303 /* An identifier index is looked up in the type
17304 being initialized, not the current scope. */
17309 {
17310 /* Substitute into the pack expansion. */
17312 in_decl);
17316 ;
17318 /* Just move the argument into place. */
17320 else
17321 {
17322 /* Update the length of the final CONSTRUCTOR
17323 arguments vector, and note that we will need to
17324 copy.*/
17327 }
17328 }
17329 else
17331 }
17334 {
17339 {
17341 {
17346 }
17347 else
17349 }
17350 }
17360 }
17363 {
17366 {
17369 }
17370 else
17371 {
17374 }
17375 }
17381 {
17382 /* We don't build decls for an instantiation of a
17383 variadic capture proxy, we instantiate the elements
17384 when needed. */
17387 }
17388 /* Fall through */
17391 {
17393 /* ??? We're doing a subset of finish_id_expression here. */
17395 && !processing_template_decl
17396 && !cp_unevaluated_operand
17399 {
17401 /* Replace an evaluated use of the thread_local variable with
17402 a call to its wrapper. */
17404 }
17406 {
17410 }
17413 /* If the original type was a reference, we'll be wrapped in
17414 the appropriate INDIRECT_REF. */
17417 }
17420 {
17424 }
17435 {
17446 }
17449 {
17455 integral_constant_expression_p);
17459 /* If the resulting list of expression statement is empty,
17460 fold it further into void_node. */
17465 }
17468 {
17486 /* For a function or variable scope, we want to use tsubst so that we
17487 don't complain about referring to an auto before deduction. */
17490 {
17491 /* Look up the parameter we want directly, as tsubst_copy
17492 doesn't do what we need. */
17498 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17501 }
17503 /* For a field, use tsubst_copy so that we look up the existing field
17504 rather than build a new one. */
17506 else
17513 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17515 /* Now that we know visibility, instantiate the type so we have a
17516 declaration of the op() for later calls to lambda_function. */
17527 }
17530 /* We can get here for a constant initializer of non-dependent type.
17531 FIXME stop folding in cp_parser_initializer_clause. */
17532 {
17534 complain);
17536 }
17540 integral_constant_expression_p));
17546 {
17551 complain));
17552 }
17558 /* Handle Objective-C++ constructs, if appropriate. */
17559 {
17560 tree subst
17565 }
17567 }
17569 #undef RECUR
17570 #undef RETURN
17571 out:
17574 }
17576 /* Verify that the instantiated ARGS are valid. For type arguments,
17577 make sure that the type's linkage is ok. For non-type arguments,
17578 make sure they are constants if they are integral or enumerations.
17579 Emit an error under control of COMPLAIN, and return TRUE on error. */
17581 static bool
17583 {
17587 {
17597 }
17599 {
17600 /* [basic.link]: A name with no linkage (notably, the name
17601 of a class or enumeration declared in a local scope)
17602 shall not be used to declare an entity with linkage.
17603 This implies that names with no linkage cannot be used as
17604 template arguments
17606 DR 757 relaxes this restriction for C++0x. */
17611 {
17612 /* DR 488 makes use of a type with no linkage cause
17613 type deduction to fail. */
17615 {
17618 else
17621 }
17623 }
17624 /* In order to avoid all sorts of complications, we do not
17625 allow variably-modified types as template arguments. */
17627 {
17631 }
17632 }
17633 /* Class template and alias template arguments should be OK. */
17635 ;
17636 /* A non-type argument of integral or enumerated type must be a
17637 constant. */
17642 {
17646 }
17648 }
17650 static bool
17652 {
17657 {
17660 }
17664 }
17666 /* We're out of SFINAE context now, so generate diagnostics for the access
17667 errors we saw earlier when instantiating D from TMPL and ARGS. */
17669 static void
17671 {
17683 }
17685 /* Instantiate the indicated variable, function, or alias template TMPL with
17686 the template arguments in TARG_PTR. */
17688 static tree
17690 {
17692 tree fndecl;
17693 tree gen_tmpl;
17694 tree spec;
17702 /* If this function is a clone, handle it specially. */
17704 {
17705 tree spec;
17706 tree clone;
17708 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
17709 DECL_CLONED_FUNCTION. */
17715 /* Look for the clone. */
17719 /* We should always have found the clone by now. */
17722 }
17727 /* Check to see if we already have this specialization. */
17731 /* targ_ptr only has the innermost template args, so add the outer ones
17732 from tmpl, which could be either a partial instantiation or gen_tmpl (in
17733 the case of a non-dependent call within a template definition). */
17734 targ_ptr = (add_outermost_template_args
17736 targ_ptr));
17738 /* It would be nice to avoid hashing here and then again in tsubst_decl,
17739 but it doesn't seem to be on the hot path. */
17748 {
17750 {
17754 }
17756 }
17759 complain))
17762 /* We are building a FUNCTION_DECL, during which the access of its
17763 parameters and return types have to be checked. However this
17764 FUNCTION_DECL which is the desired context for access checking
17765 is not built yet. We solve this chicken-and-egg problem by
17766 deferring all checks until we have the FUNCTION_DECL. */
17769 /* Instantiation of the function happens in the context of the function
17770 template, not the context of the overload resolution we're doing. */
17772 /* If there are dependent arguments, e.g. because we're doing partial
17773 ordering, make sure processing_template_decl stays set. */
17777 {
17781 }
17787 {
17788 /* We need to determine if we're using a partial or explicit
17789 specialization now, because the type of the variable could be
17790 different. */
17796 {
17801 }
17802 }
17804 /* Substitute template parameters to obtain the specialization. */
17812 {
17815 }
17817 /* The DECL_TI_TEMPLATE should always be the immediate parent
17818 template, not the most general template. */
17822 /* Now we know the specialization, compute access previously
17823 deferred. Do no access control for inheriting constructors,
17824 as we already checked access for the inherited constructor. */
17827 {
17832 }
17835 /* If we've just instantiated the main entry point for a function,
17836 instantiate all the alternate entry points as well. We do this
17837 by cloning the instantiation of the main entry point, not by
17838 instantiating the template clones. */
17843 {
17845 {
17846 /* Remember to reinstantiate when we're out of SFINAE so the user
17847 can see the errors. */
17849 }
17851 }
17853 }
17855 /* Wrapper for instantiate_template_1. */
17857 tree
17859 {
17860 tree ret;
17865 }
17867 /* Instantiate the alias template TMPL with ARGS. Also push a template
17868 instantiation level, which instantiate_template doesn't do because
17869 functions and variables have sufficient context established by the
17870 callers. */
17872 static tree
17874 {
17881 {
17884 }
17886 args =
17894 /* We can't free this if a pending_template entry or last_error_tinst_level
17895 is pointing at it. */
17901 }
17903 /* PARM is a template parameter pack for FN. Returns true iff
17904 PARM is used in a deducible way in the argument list of FN. */
17906 static bool
17908 {
17911 {
17913 tree packs;
17919 {
17920 /* The template parameter pack is used in a function parameter
17921 pack. If this is the end of the parameter list, the
17922 template parameter pack is deducible. */
17925 else
17926 /* Otherwise, not. Well, it could be deduced from
17927 a non-pack parameter, but doing so would end up with
17928 a deduction mismatch, so don't bother. */
17930 }
17931 }
17932 /* The template parameter pack isn't used in any function parameter
17933 packs, but it might be used deeper, e.g. tuple<Args...>. */
17935 }
17937 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
17938 NARGS elements of the arguments that are being used when calling
17939 it. TARGS is a vector into which the deduced template arguments
17940 are placed.
17942 Returns either a FUNCTION_DECL for the matching specialization of FN or
17943 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
17944 true, diagnostics will be printed to explain why it failed.
17946 If FN is a conversion operator, or we are trying to produce a specific
17947 specialization, RETURN_TYPE is the return type desired.
17949 The EXPLICIT_TARGS are explicit template arguments provided via a
17950 template-id.
17952 The parameter STRICT is one of:
17954 DEDUCE_CALL:
17955 We are deducing arguments for a function call, as in
17956 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
17957 deducing arguments for a call to the result of a conversion
17958 function template, as in [over.call.object].
17960 DEDUCE_CONV:
17961 We are deducing arguments for a conversion function, as in
17962 [temp.deduct.conv].
17964 DEDUCE_EXACT:
17965 We are deducing arguments when doing an explicit instantiation
17966 as in [temp.explicit], when determining an explicit specialization
17967 as in [temp.expl.spec], or when taking the address of a function
17968 template, as in [temp.deduct.funcaddr]. */
17970 tree
17972 tree explicit_targs,
17973 tree targs,
17976 tree return_type,
17977 unification_kind_t strict,
17981 {
17982 tree parms;
17983 tree fntype;
17996 tree tinst;
18002 full_targs = (add_outermost_template_args
18004 targs));
18009 /* In C++0x, it's possible to have a function template whose type depends
18010 on itself recursively. This is most obvious with decltype, but can also
18011 occur with enumeration scope (c++/48969). So we need to catch infinite
18012 recursion and reject the substitution at deduction time; this function
18013 will return error_mark_node for any repeated substitution.
18015 This also catches excessive recursion such as when f<N> depends on
18016 f<N-1> across all integers, and returns error_mark_node for all the
18017 substitutions back up to the initial one.
18019 This is, of course, not reentrant. */
18029 {
18030 /* [temp.deduct]
18032 The specified template arguments must match the template
18033 parameters in kind (i.e., type, nontype, template), and there
18034 must not be more arguments than there are parameters;
18035 otherwise type deduction fails.
18037 Nontype arguments must match the types of the corresponding
18038 nontype template parameters, or must be convertible to the
18039 types of the corresponding nontype parameters as specified in
18040 _temp.arg.nontype_, otherwise type deduction fails.
18042 All references in the function type of the function template
18043 to the corresponding template parameters are replaced by the
18044 specified template argument values. If a substitution in a
18045 template parameter or in the function type of the function
18046 template results in an invalid type, type deduction fails. */
18057 explicit_targs);
18059 /* Adjust any explicit template arguments before entering the
18060 substitution context. */
18061 explicit_targs
18063 complain,
18069 /* Substitute the explicit args into the function type. This is
18070 necessary so that, for instance, explicitly declared function
18071 arguments can match null pointed constants. If we were given
18072 an incomplete set of explicit args, we must not do semantic
18073 processing during substitution as we could create partial
18074 instantiations. */
18076 {
18081 /* Dig out the actual parm. */
18084 {
18087 }
18089 {
18092 }
18095 /* No explicit argument for this template parameter. */
18099 {
18100 /* Mark the argument pack as "incomplete". We could
18101 still deduce more arguments during unification.
18102 We remove this mark in type_unification_real. */
18104 {
18108 }
18110 /* We have some incomplete argument packs. */
18112 }
18113 }
18117 {
18120 }
18123 /* Ignore any access checks; we'll see them again in
18124 instantiate_template and they might have the wrong
18125 access path at this point. */
18137 /* Place the explicitly specified arguments in TARGS. */
18141 }
18143 /* Never do unification on the 'this' parameter. */
18147 {
18148 /* We're deducing for a call to the result of a template conversion
18149 function. The parms we really want are in return_type. */
18153 }
18155 {
18164 }
18166 /* We allow incomplete unification without an error message here
18167 because the standard doesn't seem to explicitly prohibit it. Our
18168 callers must be ready to deal with unification failures in any
18169 event. */
18172 /* If we aren't explaining yet, push tinst context so we can see where
18173 any errors (e.g. from class instantiations triggered by instantiation
18174 of default template arguments) come from. If we are explaining, this
18175 context is redundant. */
18177 {
18180 }
18182 /* type_unification_real will pass back any access checks from default
18183 template argument substitution. */
18195 /* Now that we have bindings for all of the template arguments,
18196 ensure that the arguments deduced for the template template
18197 parameters have compatible template parameter lists. We cannot
18198 check this property before we have deduced all template
18199 arguments, because the template parameter types of a template
18200 template parameter might depend on prior template parameters
18201 deduced after the template template parameter. The following
18202 ill-formed example illustrates this issue:
18204 template<typename T, template<T> class C> void f(C<5>, T);
18206 template<int N> struct X {};
18208 void g() {
18209 f(X<5>(), 5l); // error: template argument deduction fails
18210 }
18212 The template parameter list of 'C' depends on the template type
18213 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18214 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18215 time that we deduce 'C'. */
18218 {
18221 }
18223 /* All is well so far. Now, check:
18225 [temp.deduct]
18227 When all template arguments have been deduced, all uses of
18228 template parameters in nondeduced contexts are replaced with
18229 the corresponding deduced argument values. If the
18230 substitution results in an invalid type, as described above,
18231 type deduction fails. */
18234 {
18237 }
18239 /* Also collect access checks from the instantiation. */
18252 /* Now perform any access checks encountered during substitution. */
18259 /* If we're looking for an exact match, check that what we got
18260 is indeed an exact match. It might not be if some template
18261 parameters are used in non-deduced contexts. But don't check
18262 for an exact match if we have dependent template arguments;
18263 in that case we're doing partial ordering, and we already know
18264 that we have two candidates that will provide the actual type. */
18266 {
18270 tree sarg
18276 {
18280 }
18281 }
18283 /* After doing deduction with the inherited constructor, actually return an
18284 instantiation of the inheriting constructor. */
18290 fail:
18293 {
18295 /* Reset once we're all the way out. */
18297 }
18299 /* We can't free this if a pending_template entry or last_error_tinst_level
18300 is pointing at it. */
18306 }
18308 /* Adjust types before performing type deduction, as described in
18309 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18310 sections are symmetric. PARM is the type of a function parameter
18311 or the return type of the conversion function. ARG is the type of
18312 the argument passed to the call, or the type of the value
18313 initialized with the result of the conversion function.
18314 ARG_EXPR is the original argument expression, which may be null. */
18316 static int
18320 tree arg_expr)
18321 {
18325 {
18330 /* Swap PARM and ARG throughout the remainder of this
18331 function; the handling is precisely symmetric since PARM
18332 will initialize ARG rather than vice versa. */
18337 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18338 too, but here handle it by stripping the reference from PARM
18339 rather than by adding it to ARG. */
18347 /* Nothing else to do in this case. */
18352 }
18355 {
18356 /* [temp.deduct.call]
18358 If P is not a reference type:
18360 --If A is an array type, the pointer type produced by the
18361 array-to-pointer standard conversion (_conv.array_) is
18362 used in place of A for type deduction; otherwise,
18364 --If A is a function type, the pointer type produced by
18365 the function-to-pointer standard conversion
18366 (_conv.func_) is used in place of A for type deduction;
18367 otherwise,
18369 --If A is a cv-qualified type, the top level
18370 cv-qualifiers of A's type are ignored for type
18371 deduction. */
18376 else
18378 }
18380 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
18381 of the form T&&, where T is a template parameter, and the argument
18382 is an lvalue, T is deduced as A& */
18388 /* try_one_overload doesn't provide an arg_expr, but
18389 functions are always lvalues. */
18393 /* [temp.deduct.call]
18395 If P is a cv-qualified type, the top level cv-qualifiers
18396 of P's type are ignored for type deduction. If P is a
18397 reference type, the type referred to by P is used for
18398 type deduction. */
18401 {
18404 }
18406 /* DR 322. For conversion deduction, remove a reference type on parm
18407 too (which has been swapped into ARG). */
18412 }
18414 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18415 template which does contain any deducible template parameters; check if
18416 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18417 unify_one_argument. */
18419 static int
18422 {
18423 tree type;
18427 else
18434 {
18438 }
18440 {
18445 }
18449 else
18451 }
18455 /* Returns true iff the expression EXPR is one from which a template
18456 argument can be deduced. In other words, if it's an undecorated
18457 use of a template non-type parameter. */
18459 static bool
18461 {
18462 /* Strip implicit conversions. */
18466 }
18468 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18469 deducible way; that is, if it has a max value of <PARM> - 1. */
18471 static bool
18473 {
18482 }
18484 /* Returns true iff the template arguments ARGS use a template parameter
18485 in a deducible way. */
18487 static bool
18489 {
18491 {
18496 else
18497 {
18504 else
18506 }
18509 }
18511 }
18513 /* Returns true iff TYPE contains any deducible references to template
18514 parameters, as per 14.8.2.5. */
18516 static bool
18518 {
18522 /* T
18523 cv-list T
18524 TT<T>
18525 TT<i>
18526 TT<> */
18531 /* T*
18532 T&
18533 T&& */
18537 /* T[integer-constant ]
18538 type [i] */
18543 /* T type ::*
18544 type T::*
18545 T T::*
18546 T (type ::*)()
18547 type (T::*)()
18548 type (type ::*)(T)
18549 type (T::*)(T)
18550 T (type ::*)(T)
18551 T (T::*)()
18552 T (T::*)(T) */
18555 || (uses_deducible_template_parms
18558 /* template-name <T> (where template-name refers to a class template)
18559 template-name <i> (where template-name refers to a class template) */
18566 /* type (T)
18567 T()
18568 T(T) */
18571 {
18580 }
18583 }
18585 /* Subroutine of type_unification_real and unify_pack_expansion to
18586 handle unification of a single P/A pair. Parameters are as
18587 for those functions. */
18589 static int
18593 {
18600 /* We can't deduce anything from this, but we might get all the
18601 template args from other function args. */
18604 /* Implicit conversions (Clause 4) will be performed on a function
18605 argument to convert it to the type of the corresponding function
18606 parameter if the parameter type contains no template-parameters that
18607 participate in template argument deduction. */
18610 /* For function parameters with no deducible template parameters,
18611 just return. We'll check non-dependent conversions later. */
18615 {
18617 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18618 | UNIFY_ALLOW_MORE_CV_QUAL
18632 }
18634 /* We only do these transformations if this is the top-level
18635 parameter_type_list in a call or declaration matching; in other
18636 situations (nested function declarators, template argument lists) we
18637 won't be comparing a type to an expression, and we don't do any type
18638 adjustments. */
18640 {
18642 {
18645 {
18646 /* [temp.deduct.type] A template-argument can be
18647 deduced from a pointer to function or pointer
18648 to member function argument if the set of
18649 overloaded functions does not contain function
18650 templates and at most one of a set of
18651 overloaded functions provides a unique
18652 match. */
18659 }
18665 }
18667 arg_strict |=
18669 }
18670 else
18675 /* For deduction from an init-list we need the actual list. */
18679 }
18681 /* for_each_template_parm callback that always returns 0. */
18683 static int
18685 {
18687 }
18689 /* for_each_template_parm any_fn callback to handle deduction of a template
18690 type argument from the type of an array bound. */
18692 static int
18694 {
18702 {
18708 }
18710 /* Keep walking. */
18712 }
18714 /* Try to deduce any not-yet-deduced template type arguments from the type of
18715 an array bound. This is handled separately from unify because 14.8.2.5 says
18716 "The type of a type parameter is only deduced from an array bound if it is
18717 not otherwise deduced." */
18719 static void
18721 {
18726 }
18728 /* Most parms like fn_type_unification.
18730 If SUBR is 1, we're being called recursively (to unify the
18731 arguments of a function or method parameter of a function
18732 template).
18734 CHECKS is a pointer to a vector of access checks encountered while
18735 substituting default template arguments. */
18737 static int
18739 tree full_targs,
18740 tree xparms,
18744 unification_kind_t strict,
18748 {
18753 tree parms;
18764 /* Reset the number of non-defaulted template arguments contained
18765 in TARGS. */
18768 again:
18776 {
18781 /* For a function parameter pack that occurs at the end of the
18782 parameter-declaration-list, the type A of each remaining
18783 argument of the call is compared with the type P of the
18784 declarator-id of the function parameter pack. */
18790 /* For a function parameter pack that does not occur at the
18791 end of the parameter-declaration-list, the type of the
18792 parameter pack is a non-deduced context. */
18799 explain_p))
18801 }
18806 {
18807 /* Unify the remaining arguments with the pack expansion type. */
18808 tree argvec;
18811 /* Allocate a TREE_VEC and copy in all of the arguments */
18816 /* Copy the parameter into parmvec. */
18822 /* Advance to the end of the list of parameters. */
18824 }
18826 /* Fail if we've reached the end of the parm list, and more args
18827 are present, and the parm list isn't variadic. */
18830 /* Fail if parms are left and they don't have default values and
18831 they aren't all deduced as empty packs (c++/57397). This is
18832 consistent with sufficient_parms_p. */
18835 {
18839 do
18840 {
18843 count++;
18845 }
18849 type_pack_p);
18850 }
18853 {
18854 tsubst_flags_t complain = (explain_p
18855 ? tf_warning_or_error
18860 {
18864 /* Clear the "incomplete" flags on all argument packs now so that
18865 substituting them into later default arguments works. */
18867 {
18870 }
18878 {
18883 }
18885 /* If this is an undeduced nontype parameter that depends on
18886 a type parameter, try another pass; its type may have been
18887 deduced from a later argument than the one from which
18888 this parameter can be deduced. */
18892 {
18895 }
18897 /* Core issue #226 (C++0x) [temp.deduct]:
18899 If a template argument has not been deduced, its
18900 default template argument, if any, is used.
18902 When we are in C++98 mode, TREE_PURPOSE will either
18903 be NULL_TREE or ERROR_MARK_NODE, so we do not need
18904 to explicitly check cxx_dialect here. */
18906 /* OK, there is a default argument. Wait until after the
18907 conversion check to do substitution. */
18910 /* If the type parameter is a parameter pack, then it will
18911 be deduced to an empty parameter pack. */
18913 {
18914 tree arg;
18917 {
18921 }
18922 else
18929 }
18932 }
18934 /* DR 1391: All parameters have args, now check non-dependent parms for
18935 convertibility. */
18939 {
18945 /* For a function parameter pack that occurs at the end of the
18946 parameter-declaration-list, the type A of each remaining
18947 argument of the call is compared with the type P of the
18948 declarator-id of the function parameter pack. */
18954 /* For a function parameter pack that does not occur at the
18955 end of the parameter-declaration-list, the type of the
18956 parameter pack is a non-deduced context. */
18965 explain_p))
18967 }
18969 /* Now substitute into the default template arguments. */
18971 {
18997 else
18998 {
19000 /* The position of the first default template argument,
19001 is also the number of non-defaulted arguments in TARGS.
19002 Record that. */
19006 }
19007 }
19011 }
19017 }
19019 /* Subroutine of type_unification_real. Args are like the variables
19020 at the call site. ARG is an overloaded function (or template-id);
19021 we try deducing template args from each of the overloads, and if
19022 only one succeeds, we go with that. Modifies TARGS and returns
19023 true on success. */
19025 static bool
19027 tree targs,
19028 tree parm,
19029 tree arg,
19030 unification_kind_t strict,
19033 {
19040 {
19043 }
19044 else
19048 /* Handle `&x' where `x' is some static or non-static member
19049 function name. */
19055 /* Strip baselink information. */
19060 {
19061 /* If we got some explicit template args, we need to plug them into
19062 the affected templates before we try to unify, in case the
19063 explicit args will completely resolve the templates in question. */
19070 {
19083 {
19088 {
19091 }
19092 }
19095 }
19096 /* If no templates (or more than one) are fully resolved by the
19097 explicit arguments, this template-id is a non-deduced context; it
19098 could still be OK if we deduce all template arguments for the
19099 enclosing call through other arguments. */
19102 }
19105 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19106 -- but the deduction does not succeed because the expression is
19107 not just the function on its own. */
19109 else
19115 {
19118 }
19120 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19121 to function or pointer to member function argument if the set of
19122 overloaded functions does not contain function templates and at most
19123 one of a set of overloaded functions provides a unique match.
19125 So if we found multiple possibilities, we return success but don't
19126 deduce anything. */
19129 {
19133 {
19138 /* Don't forget explicit template arguments in a pack. */
19142 }
19143 }
19148 }
19150 /* Core DR 115: In contexts where deduction is done and fails, or in
19151 contexts where deduction is not done, if a template argument list is
19152 specified and it, along with any default template arguments, identifies
19153 a single function template specialization, then the template-id is an
19154 lvalue for the function template specialization. */
19156 tree
19158 {
19171 {
19174 }
19176 {
19179 }
19181 {
19184 }
19187 {
19191 /* If we got some explicit template args, we need to plug them into
19192 the affected templates before we try to unify, in case the
19193 explicit args will completely resolve the templates in question. */
19201 {
19214 {
19217 {
19220 }
19222 {
19225 }
19226 }
19227 }
19229 {
19237 {
19238 tree base
19241 }
19245 }
19247 /* There were no good options and at least one bad one, so let the
19248 user know what the problem is. */
19250 }
19252 }
19254 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19255 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19256 different overloads deduce different arguments for a given parm.
19257 ADDR_P is true if the expression for which deduction is being
19258 performed was of the form "& fn" rather than simply "fn".
19260 Returns 1 on success. */
19262 static int
19264 tree orig_targs,
19265 tree targs,
19266 tree parm,
19267 tree arg,
19268 unification_kind_t strict,
19272 {
19274 tree tempargs;
19280 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19281 to function or pointer to member function argument if the set of
19282 overloaded functions does not contain function templates and at most
19283 one of a set of overloaded functions provides a unique match.
19285 So if this is a template, just return success. */
19297 /* We don't copy orig_targs for this because if we have already deduced
19298 some template args from previous args, unify would complain when we
19299 try to deduce a template parameter for the same argument, even though
19300 there isn't really a conflict. */
19307 /* First make sure we didn't deduce anything that conflicts with
19308 explicitly specified args. */
19310 {
19317 /* Since we're unifying against ourselves, we will fill in
19318 template args used in the function parm list with our own
19319 template parms. Discard them. */
19322 {
19323 /* Check that the argument at each index of the deduced argument pack
19324 is equivalent to the corresponding explicitly specified argument.
19325 We may have deduced more arguments than were explicitly specified,
19326 and that's OK. */
19342 }
19345 }
19348 {
19353 }
19356 }
19358 /* PARM is a template class (perhaps with unbound template
19359 parameters). ARG is a fully instantiated type. If ARG can be
19360 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19361 TARGS are as for unify. */
19363 static tree
19366 {
19367 tree copy_of_targs;
19374 /* We need to make a new template argument vector for the call to
19375 unify. If we used TARGS, we'd clutter it up with the result of
19376 the attempted unification, even if this class didn't work out.
19377 We also don't want to commit ourselves to all the unifications
19378 we've already done, since unification is supposed to be done on
19379 an argument-by-argument basis. In other words, consider the
19380 following pathological case:
19382 template <int I, int J, int K>
19383 struct S {};
19385 template <int I, int J>
19386 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19388 template <int I, int J, int K>
19389 void f(S<I, J, K>, S<I, I, I>);
19391 void g() {
19392 S<0, 0, 0> s0;
19393 S<0, 1, 2> s2;
19395 f(s0, s2);
19396 }
19398 Now, by the time we consider the unification involving `s2', we
19399 already know that we must have `f<0, 0, 0>'. But, even though
19400 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19401 because there are two ways to unify base classes of S<0, 1, 2>
19402 with S<I, I, I>. If we kept the already deduced knowledge, we
19403 would reject the possibility I=1. */
19406 /* If unification failed, we're done. */
19412 }
19414 /* Given a template type PARM and a class type ARG, find the unique
19415 base type in ARG that is an instance of PARM. We do not examine
19416 ARG itself; only its base-classes. If there is not exactly one
19417 appropriate base class, return NULL_TREE. PARM may be the type of
19418 a partial specialization, as well as a plain template type. Used
19419 by unify. */
19421 static enum template_base_result
19424 {
19426 tree binfo;
19432 {
19433 /* The type could not be completed. */
19436 }
19438 /* Walk in inheritance graph order. The search order is not
19439 important, and this avoids multiple walks of virtual bases. */
19441 {
19446 {
19447 /* If there is more than one satisfactory baseclass, then:
19449 [temp.deduct.call]
19451 If they yield more than one possible deduced A, the type
19452 deduction fails.
19454 applies. */
19456 {
19459 }
19462 }
19463 }
19467 }
19469 /* Returns the level of DECL, which declares a template parameter. */
19471 static int
19473 {
19475 {
19485 }
19487 }
19489 /* Decide whether ARG can be unified with PARM, considering only the
19490 cv-qualifiers of each type, given STRICT as documented for unify.
19491 Returns nonzero iff the unification is OK on that basis. */
19493 static int
19495 {
19501 {
19502 /* Although a CVR qualifier is ignored when being applied to a
19503 substituted template parameter ([8.3.2]/1 for example), that
19504 does not allow us to unify "const T" with "int&" because both
19505 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19506 It is ok when we're allowing additional CV qualifiers
19507 at the outer level [14.8.2.1]/3,1st bullet. */
19517 }
19528 }
19530 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19531 void
19533 {
19537 {
19540 }
19541 else
19542 {
19545 }
19546 }
19548 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19549 do { \
19550 if (unify (TP, TA, P, A, S, EP)) \
19551 return 1; \
19552 } while (0)
19554 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19555 expansion at the end of PACKED_PARMS. Returns 0 if the type
19556 deduction succeeds, 1 otherwise. STRICT is the same as in
19557 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19558 function call argument list. We'll need to adjust the arguments to make them
19559 types. SUBR tells us if this is from a recursive call to
19560 type_unification_real, or for comparing two template argument
19561 lists. */
19563 static int
19567 {
19568 tree parm
19578 /* Determine the parameter packs we will be deducing from the
19579 pattern, and record their current deductions. */
19582 {
19586 /* Determine the index and level of this parameter pack. */
19589 /* Keep track of the parameter packs and their corresponding
19590 argument packs. */
19593 }
19595 /* Loop through all of the arguments that have not yet been
19596 unified and unify each with the pattern. */
19598 {
19599 tree parm;
19603 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19604 or the element of its argument pack at the current index if
19605 this argument was explicitly specified. */
19607 {
19616 {
19619 }
19621 }
19623 /* If we had explicit template arguments, substitute them into the
19624 pattern before deduction. */
19626 {
19627 /* Some arguments might still be unspecified or dependent. */
19635 NULL_TREE);
19640 }
19641 else
19644 /* Unify the pattern with the current argument. */
19646 explain_p))
19649 /* For each parameter pack, collect the deduced value. */
19651 {
19657 }
19658 }
19660 /* Verify that the results of unification with the parameter packs
19661 produce results consistent with what we've seen before, and make
19662 the deduced argument packs available. */
19664 {
19671 /* By default keep the original deduced argument pack.
19672 If necessary, more specific code is going to update the
19673 resulting deduced argument later down in this function. */
19677 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
19678 actually deduce anything. */
19686 {
19687 /* If we had fewer function args than explicit template args,
19688 just use the explicits. */
19693 }
19696 {
19697 tree result;
19698 /* Build the deduced *_ARGUMENT_PACK. */
19700 {
19705 }
19706 else
19711 /* Note the deduced argument packs for this parameter
19712 pack. */
19714 }
19718 {
19719 /* We only had the explicitly-provided arguments before, but
19720 now we have a complete set of arguments. */
19726 }
19727 else
19728 {
19734 /* Inconsistent unification of this parameter pack. */
19736 bad_old_arg,
19737 bad_new_arg);
19738 }
19739 }
19742 }
19744 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
19745 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
19746 parameters and return value are as for unify. */
19748 static int
19752 {
19753 tree parm_max;
19754 tree arg_max;
19758 /* Our representation of array types uses "N - 1" as the
19759 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
19760 not an integer constant. We cannot unify arbitrarily
19761 complex expressions, so we eliminate the MINUS_EXPRs
19762 here. */
19766 {
19769 }
19773 {
19774 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
19775 trying to unify the type of a variable with the type
19776 of a template parameter. For example:
19778 template <unsigned int N>
19779 void f (char (&) [N]);
19780 int g();
19781 void h(int i) {
19782 char a[g(i)];
19783 f(a);
19784 }
19786 Here, the type of the ARG will be "int [g(i)]", and
19787 may be a SAVE_EXPR, etc. */
19791 }
19793 /* If only one of the bounds used a MINUS_EXPR, compensate
19794 by adding one to the other bound. */
19797 integer_type_node,
19798 parm_max,
19799 integer_one_node);
19802 integer_type_node,
19803 arg_max,
19804 integer_one_node);
19808 }
19810 /* Deduce the value of template parameters. TPARMS is the (innermost)
19811 set of template parameters to a template. TARGS is the bindings
19812 for those template parameters, as determined thus far; TARGS may
19813 include template arguments for outer levels of template parameters
19814 as well. PARM is a parameter to a template function, or a
19815 subcomponent of that parameter; ARG is the corresponding argument.
19816 This function attempts to match PARM with ARG in a manner
19817 consistent with the existing assignments in TARGS. If more values
19818 are deduced, then TARGS is updated.
19820 Returns 0 if the type deduction succeeds, 1 otherwise. The
19821 parameter STRICT is a bitwise or of the following flags:
19823 UNIFY_ALLOW_NONE:
19824 Require an exact match between PARM and ARG.
19825 UNIFY_ALLOW_MORE_CV_QUAL:
19826 Allow the deduced ARG to be more cv-qualified (by qualification
19827 conversion) than ARG.
19828 UNIFY_ALLOW_LESS_CV_QUAL:
19829 Allow the deduced ARG to be less cv-qualified than ARG.
19830 UNIFY_ALLOW_DERIVED:
19831 Allow the deduced ARG to be a template base class of ARG,
19832 or a pointer to a template base class of the type pointed to by
19833 ARG.
19834 UNIFY_ALLOW_INTEGER:
19835 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
19836 case for more information.
19837 UNIFY_ALLOW_OUTER_LEVEL:
19838 This is the outermost level of a deduction. Used to determine validity
19839 of qualification conversions. A valid qualification conversion must
19840 have const qualified pointers leading up to the inner type which
19841 requires additional CV quals, except at the outer level, where const
19842 is not required [conv.qual]. It would be normal to set this flag in
19843 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
19844 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
19845 This is the outermost level of a deduction, and PARM can be more CV
19846 qualified at this point.
19847 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
19848 This is the outermost level of a deduction, and PARM can be less CV
19849 qualified at this point. */
19851 static int
19854 {
19856 tree targ;
19857 tree tparm;
19859 tsubst_flags_t complain = (explain_p
19860 ? tf_warning_or_error
19863 /* I don't think this will do the right thing with respect to types.
19864 But the only case I've seen it in so far has been array bounds, where
19865 signedness is the only information lost, and I think that will be
19866 okay. */
19874 /* We can't deduce anything from this, but we might get all the
19875 template args from other function args. */
19878 /* If PARM uses template parameters, then we can't bail out here,
19879 even if ARG == PARM, since we won't record unifications for the
19880 template parameters. We might need them if we're trying to
19881 figure out which of two things is more specialized. */
19885 /* Handle init lists early, so the rest of the function can assume
19886 we're dealing with a type. */
19888 {
19893 /* Replace T with std::initializer_list<T> for deduction. */
19900 /* We can only deduce from an initializer list argument if the
19901 parameter is std::initializer_list or an array; otherwise this
19902 is a non-deduced context. */
19907 else
19908 {
19910 /* Deduction is defined in terms of a single type, so just punt
19911 on the (bizarre) std::initializer_list<T...>. */
19914 }
19917 {
19924 {
19928 /* It should only be possible to get here for a call. */
19930 elt_strict |= maybe_adjust_types_for_deduction
19933 }
19936 explain_p);
19937 }
19941 {
19942 /* Also deduce from the length of the initializer list. */
19949 }
19951 /* If the std::initializer_list<T> deduction worked, replace the
19952 deduced A with std::initializer_list<A>. */
19954 {
19959 }
19961 }
19963 /* Immediately reject some pairs that won't unify because of
19964 cv-qualification mismatches. */
19967 /* It is the elements of the array which hold the cv quals of an array
19968 type, and the elements might be template type parms. We'll check
19969 when we recurse. */
19971 /* We check the cv-qualifiers when unifying with template type
19972 parameters below. We want to allow ARG `const T' to unify with
19973 PARM `T' for example, when computing which of two templates
19974 is more specialized, for example. */
19988 {
19992 /* In a type which contains a nested-name-specifier, template
19993 argument values cannot be deduced for template parameters used
19994 within the nested-name-specifier. */
20006 /* The PARM is not one we're trying to unify. Just check
20007 to see if it matches ARG. */
20008 {
20013 else
20015 }
20022 /* Check for mixed types and values. */
20030 {
20031 /* ARG must be constructed from a template class or a template
20032 template parameter. */
20036 {
20038 /* An alias template name is never deduced. */
20043 tree parm_parms
20044 = DECL_INNERMOST_TEMPLATE_PARMS
20049 /* The resolution to DR150 makes clear that default
20050 arguments for an N-argument may not be used to bind T
20051 to a template template parameter with fewer than N
20052 parameters. It is not safe to permit the binding of
20053 default arguments as an extension, as that may change
20054 the meaning of a conforming program. Consider:
20056 struct Dense { static const unsigned int dim = 1; };
20058 template <template <typename> class View,
20059 typename Block>
20060 void operator+(float, View<Block> const&);
20062 template <typename Block,
20063 unsigned int Dim = Block::dim>
20064 struct Lvalue_proxy { operator float() const; };
20066 void
20067 test_1d (void) {
20068 Lvalue_proxy<Dense> p;
20069 float b;
20070 b + p;
20071 }
20073 Here, if Lvalue_proxy is permitted to bind to View, then
20074 the global operator+ will be used; if they are not, the
20075 Lvalue_proxy will be converted to float. */
20077 full_argvec,
20079 complain,
20085 /* Deduce arguments T, i from TT<T> or TT<i>.
20086 We check each element of PARMVEC and ARGVEC individually
20087 rather than the whole TREE_VEC since they can have
20088 different number of elements. */
20095 /* Check if the parameters end in a pack, making them
20096 variadic. */
20102 /* If the template argument list of P contains a pack
20103 expansion that is not the last template argument, the
20104 entire template argument list is a non-deduced
20105 context. */
20114 {
20119 }
20124 DEDUCE_EXACT,
20127 }
20130 /* Fall through to deduce template name. */
20131 }
20135 {
20136 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20138 /* Simple cases: Value already set, does match or doesn't. */
20143 }
20144 else
20145 {
20146 /* If PARM is `const T' and ARG is only `int', we don't have
20147 a match unless we are allowing additional qualification.
20148 If ARG is `const int' and PARM is just `T' that's OK;
20149 that binds `const int' to `T'. */
20154 /* Consider the case where ARG is `const volatile int' and
20155 PARM is `const T'. Then, T should be `volatile int'. */
20156 arg = cp_build_qualified_type_real
20161 /* Simple cases: Value already set, does match or doesn't. */
20167 /* Make sure that ARG is not a variable-sized array. (Note
20168 that were talking about variable-sized arrays (like
20169 `int[n]'), rather than arrays of unknown size (like
20170 `int[]').) We'll get very confused by such a type since
20171 the bound of the array is not constant, and therefore
20172 not mangleable. Besides, such types are not allowed in
20173 ISO C++, so we can do as we please here. We do allow
20174 them for 'auto' deduction, since that isn't ABI-exposed. */
20178 /* Strip typedefs as in convert_template_argument. */
20180 }
20182 /* If ARG is a parameter pack or an expansion, we cannot unify
20183 against it unless PARM is also a parameter pack. */
20188 /* If the argument deduction results is a METHOD_TYPE,
20189 then there is a problem.
20190 METHOD_TYPE doesn't map to any real C++ type the result of
20191 the deduction can not be of that type. */
20205 {
20206 /* The PARM is not one we're trying to unify. Just check
20207 to see if it matches ARG. */
20213 }
20219 {
20224 }
20227 /* We deduce from array bounds in try_array_deduction. */
20231 {
20236 }
20238 /* [temp.deduct.type] If, in the declaration of a function template
20239 with a non-type template-parameter, the non-type
20240 template-parameter is used in an expression in the function
20241 parameter-list and, if the corresponding template-argument is
20242 deduced, the template-argument type shall match the type of the
20243 template-parameter exactly, except that a template-argument
20244 deduced from an array bound may be of any integral type.
20245 The non-type parameter might use already deduced type parameters. */
20248 {
20252 }
20255 /* Template-parameter dependent expression. Just accept it for now.
20256 It will later be processed in convert_template_argument. */
20257 ;
20262 /* Convert the ARG to the type of PARM; the deduced non-type
20263 template argument must exactly match the types of the
20264 corresponding parameter. */
20267 /* We haven't deduced the type of this parameter yet. Try again
20268 later. */
20270 else
20273 /* If ARG is a parameter pack or an expansion, we cannot unify
20274 against it unless PARM is also a parameter pack. */
20279 {
20282 }
20287 {
20288 /* A pointer-to-member constant can be unified only with
20289 another constant. */
20293 /* Just unify the class member. It would be useless (and possibly
20294 wrong, depending on the strict flags) to unify also
20295 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20296 arg refer to the same variable, even if through different
20297 classes. For instance:
20299 struct A { int x; };
20300 struct B : A { };
20302 Unification of &A::x and &B::x must succeed. */
20305 }
20308 {
20312 /* [temp.deduct.call]
20314 A can be another pointer or pointer to member type that can
20315 be converted to the deduced A via a qualification
20316 conversion (_conv.qual_).
20318 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20319 This will allow for additional cv-qualification of the
20320 pointed-to types if appropriate. */
20323 /* The derived-to-base conversion only persists through one
20324 level of pointers. */
20329 }
20361 /* We have already checked cv-qualification at the top of the
20362 function. */
20366 /* As far as unification is concerned, this wins. Later checks
20367 will invalidate it if necessary. */
20370 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20371 /* Type INTEGER_CST can come from ordinary constant template args. */
20383 {
20393 /* Check for pack expansions in the parameters. */
20395 {
20397 {
20399 /* We can unify against something with a trailing
20400 parameter pack. */
20402 else
20403 /* [temp.deduct.type]/9: If the template argument list of
20404 P contains a pack expansion that is not the last
20405 template argument, the entire template argument list
20406 is a non-deduced context. */
20408 }
20409 }
20411 /* If we don't have enough arguments to satisfy the parameters
20412 (not counting the pack expression at the end), or we have
20413 too many arguments for a parameter list that doesn't end in
20414 a pack expression, we can't unify. */
20420 /* Unify all of the parameters that precede the (optional)
20421 pack expression. */
20423 {
20428 }
20431 DEDUCE_EXACT,
20434 }
20442 {
20450 }
20455 {
20459 {
20460 /* First, we try to unify the PARM and ARG directly. */
20465 {
20466 /* Fallback to the special case allowed in
20467 [temp.deduct.call]:
20469 If P is a class, and P has the form
20470 template-id, then A can be a derived class of
20471 the deduced A. Likewise, if P is a pointer to
20472 a class of the form template-id, A can be a
20473 pointer to a derived class pointed to by the
20474 deduced A. */
20480 {
20481 /* Don't give the derived diagnostic if we're
20482 already dealing with the same template. */
20483 bool same_template
20489 }
20490 }
20491 }
20495 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20496 Then, we should unify `int' and `U'. */
20498 else
20499 /* There's no chance of unification succeeding. */
20504 }
20511 {
20514 tree a;
20520 /* CV qualifications for methods can never be deduced, they must
20521 match exactly. We need to check them explicitly here,
20522 because type_unification_real treats them as any other
20523 cv-qualified parameter. */
20525 && (!check_cv_quals_for_unify
20553 {
20565 }
20568 }
20571 /* Unify a pointer to member with a pointer to member function, which
20572 deduces the type of the member as a function type. */
20574 {
20575 /* Check top-level cv qualifiers */
20583 /* Determine the type of the function we are unifying against. */
20587 }
20606 /* Matched cases are handled by the ARG == PARM test above. */
20610 /* We might get a variable as a non-type template argument in parm if the
20611 corresponding parameter is type-dependent. Make any necessary
20612 adjustments based on whether arg is a reference. */
20616 {
20621 }
20622 /* Now use the normal expression code to check whether they match. */
20633 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20634 or UNDERLYING_TYPE nodes. */
20638 /* Unification fails if we hit an error node. */
20643 {
20648 }
20649 /* FALLTHRU */
20652 /* An unresolved overload is a nondeduced context. */
20656 expr:
20657 /* We must be looking at an expression. This can happen with
20658 something like:
20660 template <int I>
20661 void foo(S<I>, S<I + 2>);
20663 This is a "nondeduced context":
20665 [deduct.type]
20667 The nondeduced contexts are:
20669 --A type that is a template-id in which one or more of
20670 the template-arguments is an expression that references
20671 a template-parameter.
20673 In these cases, we assume deduction succeeded, but don't
20674 actually infer any unifications. */
20679 else
20681 }
20682 }
20683 #undef RECUR_AND_CHECK_FAILURE
20684 \f
20685 /* Note that DECL can be defined in this translation unit, if
20686 required. */
20688 static void
20690 {
20691 tree clone;
20695 }
20697 /* Called if RESULT is explicitly instantiated, or is a member of an
20698 explicitly instantiated class. */
20700 void
20702 {
20705 /* If this entity has already been written out, it's too late to
20706 make any modifications. */
20710 /* For anonymous namespace we don't need to do anything. */
20712 {
20715 }
20718 /* The TREE_PUBLIC flag for function declarations will have been
20719 set correctly by tsubst. */
20722 /* This might have been set by an earlier implicit instantiation. */
20727 else
20728 {
20731 /* Always make artificials weak. */
20734 /* For WIN32 we also want to put explicit instantiations in
20735 linkonce sections. */
20738 }
20740 /* If EXTERN_P, then this function will not be emitted -- unless
20741 followed by an explicit instantiation, at which point its linkage
20742 will be adjusted. If !EXTERN_P, then this function will be
20743 emitted here. In neither circumstance do we want
20744 import_export_decl to adjust the linkage. */
20746 }
20748 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
20749 important template arguments. If any are missing, we check whether
20750 they're important by using error_mark_node for substituting into any
20751 args that were used for partial ordering (the ones between ARGS and END)
20752 and seeing if it bubbles up. */
20754 static bool
20756 {
20761 {
20764 }
20766 {
20770 }
20772 }
20774 /* Given two function templates PAT1 and PAT2, return:
20776 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
20777 -1 if PAT2 is more specialized than PAT1.
20778 0 if neither is more specialized.
20780 LEN indicates the number of parameters we should consider
20781 (defaulted parameters should not be considered).
20783 The 1998 std underspecified function template partial ordering, and
20784 DR214 addresses the issue. We take pairs of arguments, one from
20785 each of the templates, and deduce them against each other. One of
20786 the templates will be more specialized if all the *other*
20787 template's arguments deduce against its arguments and at least one
20788 of its arguments *does* *not* deduce against the other template's
20789 corresponding argument. Deduction is done as for class templates.
20790 The arguments used in deduction have reference and top level cv
20791 qualifiers removed. Iff both arguments were originally reference
20792 types *and* deduction succeeds in both directions, an lvalue reference
20793 wins against an rvalue reference and otherwise the template
20794 with the more cv-qualified argument wins for that pairing (if
20795 neither is more cv-qualified, they both are equal). Unlike regular
20796 deduction, after all the arguments have been deduced in this way,
20797 we do *not* verify the deduced template argument values can be
20798 substituted into non-deduced contexts.
20800 The logic can be a bit confusing here, because we look at deduce1 and
20801 targs1 to see if pat2 is at least as specialized, and vice versa; if we
20802 can find template arguments for pat1 to make arg1 look like arg2, that
20803 means that arg2 is at least as specialized as arg1. */
20805 int
20807 {
20820 /* Remove the this parameter from non-static member functions. If
20821 one is a non-static member function and the other is not a static
20822 member function, remove the first parameter from that function
20823 also. This situation occurs for operator functions where we
20824 locate both a member function (with this pointer) and non-member
20825 operator (with explicit first operand). */
20827 {
20832 }
20834 {
20837 {
20838 len--;
20840 }
20841 }
20843 /* If only one is a conversion operator, they are unordered. */
20847 /* Consider the return type for a conversion function */
20849 {
20852 len++;
20853 }
20855 processing_template_decl++;
20861 /* Stop when an ellipsis is seen. */
20863 {
20874 {
20875 /* When both arguments are pack expansions, we need only
20876 unify the patterns themselves. */
20880 /* This is the last comparison we need to do. */
20882 }
20885 {
20889 }
20892 {
20896 }
20902 {
20908 /* Setup the parameter vector, which contains only ARG1. */
20911 /* Setup the argument vector, which contains the remaining
20912 arguments. */
20921 /* We cannot deduce in the other direction, because ARG1 is
20922 a pack expansion but ARG2 is not. */
20924 }
20926 {
20932 /* Setup the parameter vector, which contains only ARG1. */
20935 /* Setup the argument vector, which contains the remaining
20936 arguments. */
20945 /* We cannot deduce in the other direction, because ARG2 is
20946 a pack expansion but ARG1 is not.*/
20948 }
20950 else
20951 {
20952 /* The normal case, where neither argument is a pack
20953 expansion. */
20960 }
20962 /* If we couldn't deduce arguments for tparms1 to make arg1 match
20963 arg2, then arg2 is not as specialized as arg1. */
20969 /* "If, for a given type, deduction succeeds in both directions
20970 (i.e., the types are identical after the transformations above)
20971 and both P and A were reference types (before being replaced with
20972 the type referred to above):
20973 - if the type from the argument template was an lvalue reference and
20974 the type from the parameter template was not, the argument type is
20975 considered to be more specialized than the other; otherwise,
20976 - if the type from the argument template is more cv-qualified
20977 than the type from the parameter template (as described above),
20978 the argument type is considered to be more specialized than the other;
20979 otherwise,
20980 - neither type is more specialized than the other." */
20983 {
20985 {
20988 else
20990 }
20992 {
20997 }
20998 }
21001 /* We've failed to deduce something in either direction.
21002 These must be unordered. */
21007 /* We have already processed all of the arguments in our
21008 handing of the pack expansion type. */
21013 }
21015 /* "In most cases, all template parameters must have values in order for
21016 deduction to succeed, but for partial ordering purposes a template
21017 parameter may remain without a value provided it is not used in the
21018 types being used for partial ordering."
21020 Thus, if we are missing any of the targs1 we need to substitute into
21021 origs1, then pat2 is not as specialized as pat1. This can happen when
21022 there is a nondeduced context. */
21028 processing_template_decl--;
21030 /* If both deductions succeed, the partial ordering selects the more
21031 constrained template. */
21033 {
21038 }
21040 /* All things being equal, if the next argument is a pack expansion
21041 for one function but not for the other, prefer the
21042 non-variadic function. FIXME this is bogus; see c++/41958. */
21046 {
21049 }
21055 else
21057 }
21059 /* Determine which of two partial specializations of TMPL is more
21060 specialized.
21062 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21063 to the first partial specialization. The TREE_PURPOSE is the
21064 innermost set of template parameters for the partial
21065 specialization. PAT2 is similar, but for the second template.
21067 Return 1 if the first partial specialization is more specialized;
21068 -1 if the second is more specialized; 0 if neither is more
21069 specialized.
21071 See [temp.class.order] for information about determining which of
21072 two templates is more specialized. */
21074 static int
21076 {
21077 tree targs;
21086 /* Just like what happens for functions, if we are ordering between
21087 different template specializations, we may encounter dependent
21088 types in the arguments, and we need our dependency check functions
21089 to behave correctly. */
21093 {
21096 }
21100 {
21103 }
21106 /* If both deductions succeed, the partial ordering selects the more
21107 constrained template. */
21111 /* In the case of a tie where at least one of the templates
21112 has a parameter pack at the end, the template with the most
21113 non-packed parameters wins. */
21115 && any_deductions
21118 {
21124 /* We don't count the pack expansion at the end. */
21134 }
21137 }
21139 /* Return the template arguments that will produce the function signature
21140 DECL from the function template FN, with the explicit template
21141 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21142 also match. Return NULL_TREE if no satisfactory arguments could be
21143 found. */
21145 static tree
21147 {
21151 tree decl_arg_types;
21154 tree arg;
21158 /* Never do unification on the 'this' parameter. */
21179 }
21181 /* Return the innermost template arguments that, when applied to a partial
21182 specialization SPEC_TMPL of TMPL, yield the ARGS.
21184 For example, suppose we have:
21186 template <class T, class U> struct S {};
21187 template <class T> struct S<T*, int> {};
21189 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21190 partial specialization and the ARGS will be {double*, int}. The resulting
21191 vector will be {double}, indicating that `T' is bound to `double'. */
21193 static tree
21195 {
21197 tree spec_args
21200 tree deduced_args;
21201 tree innermost_deduced_args;
21205 {
21209 innermost_deduced_args);
21210 }
21211 else
21215 again:
21224 {
21226 {
21232 }
21234 }
21238 {
21241 }
21243 /* Verify that nondeduced template arguments agree with the type
21244 obtained from argument deduction.
21246 For example:
21248 struct A { typedef int X; };
21249 template <class T, class U> struct C {};
21250 template <class T> struct C<T, typename T::X> {};
21252 Then with the instantiation `C<A, int>', we can deduce that
21253 `T' is `A' but unify () does not check whether `typename T::X'
21254 is `int'. */
21263 /* We only need to check the innermost arguments; the other
21264 arguments will always agree. */
21269 /* Now that we have bindings for all of the template arguments,
21270 ensure that the arguments deduced for the template template
21271 parameters have compatible template parameter lists. See the use
21272 of template_template_parm_bindings_ok_p in fn_type_unification
21273 for more information. */
21278 }
21280 // Compare two function templates T1 and T2 by deducing bindings
21281 // from one against the other. If both deductions succeed, compare
21282 // constraints to see which is more constrained.
21283 static int
21285 {
21290 {
21293 }
21296 {
21299 }
21301 // If both deductions succeed, then one may be more constrained.
21306 }
21308 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21309 Return the TREE_LIST node with the most specialized template, if
21310 any. If there is no most specialized template, the error_mark_node
21311 is returned.
21313 Note that this function does not look at, or modify, the
21314 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21315 returned is one of the elements of INSTANTIATIONS, callers may
21316 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21317 and retrieve it from the value returned. */
21319 tree
21321 {
21328 {
21333 {
21334 /* Equally specialized, move to next function. If there
21335 is no next function, nothing's most specialized. */
21340 }
21341 }
21344 /* Now verify that champ is better than everything earlier in the
21345 instantiation list. */
21348 {
21351 }
21352 }
21354 processing_template_decl--;
21360 }
21362 /* If DECL is a specialization of some template, return the most
21363 general such template. Otherwise, returns NULL_TREE.
21365 For example, given:
21367 template <class T> struct S { template <class U> void f(U); };
21369 if TMPL is `template <class U> void S<int>::f(U)' this will return
21370 the full template. This function will not trace past partial
21371 specializations, however. For example, given in addition:
21373 template <class T> struct S<T*> { template <class U> void f(U); };
21375 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21376 `template <class T> template <class U> S<T*>::f(U)'. */
21378 tree
21380 {
21382 {
21385 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21386 template friend, or a FIELD_DECL for a capture pack. */
21389 }
21391 /* Look for more and more general templates. */
21393 {
21394 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21395 (See cp-tree.h for details.) */
21404 /* Stop if we run into an explicitly specialized class template. */
21411 }
21414 }
21416 /* Return the most specialized of the template partial specializations
21417 which can produce TARGET, a specialization of some class or variable
21418 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21419 a TEMPLATE_DECL node corresponding to the partial specialization, while
21420 the TREE_PURPOSE is the set of template arguments that must be
21421 substituted into the template pattern in order to generate TARGET.
21423 If the choice of partial specialization is ambiguous, a diagnostic
21424 is issued, and the error_mark_node is returned. If there are no
21425 partial specializations matching TARGET, then NULL_TREE is
21426 returned, indicating that the primary template should be used. */
21428 static tree
21430 {
21432 tree t;
21433 tree champ;
21440 {
21444 }
21446 {
21449 }
21451 {
21455 }
21456 else
21461 /* For determining which partial specialization to use, only the
21462 innermost args are interesting. */
21464 {
21467 }
21470 {
21471 tree spec_args;
21475 {
21476 /* Substitute in the template args from the enclosing class. */
21480 }
21487 {
21491 /* Keep the candidate only if the constraints are satisfied,
21492 or if we're not compiling with concepts. */
21495 {
21498 }
21499 }
21500 }
21510 {
21513 ;
21514 else
21515 {
21517 {
21520 {
21523 }
21524 }
21526 }
21527 }
21531 {
21534 {
21537 }
21538 }
21541 {
21548 else
21552 {
21557 }
21560 }
21563 }
21565 /* Explicitly instantiate DECL. */
21567 void
21569 {
21574 /* An error occurred, for which grokdeclarator has already issued
21575 an appropriate message. */
21578 {
21581 }
21587 {
21588 /* There is an asymmetry here in the way VAR_DECLs and
21589 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21590 the latter, the DECL we get back will be marked as a
21591 template instantiation, and the appropriate
21592 DECL_TEMPLATE_INFO will be set up. This does not happen for
21593 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21594 should handle VAR_DECLs as it currently handles
21595 FUNCTION_DECLs. */
21597 {
21600 }
21603 {
21606 }
21608 {
21613 }
21614 }
21616 {
21619 }
21620 else
21623 /* Check for various error cases. Note that if the explicit
21624 instantiation is valid the RESULT will currently be marked as an
21625 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21626 until we get here. */
21629 {
21630 /* DR 259 [temp.spec].
21632 Both an explicit instantiation and a declaration of an explicit
21633 specialization shall not appear in a program unless the explicit
21634 instantiation follows a declaration of the explicit specialization.
21636 For a given set of template parameters, if an explicit
21637 instantiation of a template appears after a declaration of an
21638 explicit specialization for that template, the explicit
21639 instantiation has no effect. */
21641 }
21643 {
21644 /* [temp.spec]
21646 No program shall explicitly instantiate any template more
21647 than once.
21649 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21650 the first instantiation was `extern' and the second is not,
21651 and EXTERN_P for the opposite case. */
21654 /* If an "extern" explicit instantiation follows an ordinary
21655 explicit instantiation, the template is instantiated. */
21658 }
21660 {
21663 }
21665 {
21668 }
21671 ;
21673 {
21676 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21679 }
21680 else
21688 }
21690 static void
21692 {
21698 {
21701 }
21702 }
21704 /* Called from do_type_instantiation through binding_table_foreach to
21705 do recursive instantiation for the type bound in ENTRY. */
21706 static void
21708 {
21714 }
21716 /* Called from do_type_instantiation to instantiate a member
21717 (a member function or a static member variable) of an
21718 explicitly instantiated class template. */
21719 static void
21721 {
21726 }
21728 /* Perform an explicit instantiation of template class T. STORAGE, if
21729 non-null, is the RID for extern, inline or static. COMPLAIN is
21730 nonzero if this is called from the parser, zero if called recursively,
21731 since the standard is unclear (as detailed below). */
21733 void
21735 {
21745 {
21746 tree tmpl =
21750 else
21753 }
21758 {
21761 t);
21763 }
21766 {
21768 {
21770 {
21773 "ISO C++ 1998 forbids the use of %<extern%> on "
21775 }
21776 else
21778 "ISO C++ forbids the use of %qE"
21780 }
21788 else
21789 {
21791 storage);
21793 }
21794 }
21797 {
21798 /* DR 259 [temp.spec].
21800 Both an explicit instantiation and a declaration of an explicit
21801 specialization shall not appear in a program unless the explicit
21802 instantiation follows a declaration of the explicit specialization.
21804 For a given set of template parameters, if an explicit
21805 instantiation of a template appears after a declaration of an
21806 explicit specialization for that template, the explicit
21807 instantiation has no effect. */
21809 }
21811 {
21812 /* [temp.spec]
21814 No program shall explicitly instantiate any template more
21815 than once.
21817 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
21818 instantiation was `extern'. If EXTERN_P then the second is.
21819 These cases are OK. */
21826 /* If we've already instantiated the template, just return now. */
21829 }
21837 {
21838 tree tmp;
21840 /* In contrast to implicit instantiation, where only the
21841 declarations, and not the definitions, of members are
21842 instantiated, we have here:
21844 [temp.explicit]
21846 The explicit instantiation of a class template specialization
21847 implies the instantiation of all of its members not
21848 previously explicitly specialized in the translation unit
21849 containing the explicit instantiation.
21851 Of course, we can't instantiate member template classes, since
21852 we don't have any arguments for them. Note that the standard
21853 is unclear on whether the instantiation of the members are
21854 *explicit* instantiations or not. However, the most natural
21855 interpretation is that it should be an explicit instantiation. */
21871 }
21872 }
21874 /* Given a function DECL, which is a specialization of TMPL, modify
21875 DECL to be a re-instantiation of TMPL with the same template
21876 arguments. TMPL should be the template into which tsubst'ing
21877 should occur for DECL, not the most general template.
21879 One reason for doing this is a scenario like this:
21881 template <class T>
21882 void f(const T&, int i);
21884 void g() { f(3, 7); }
21886 template <class T>
21887 void f(const T& t, const int i) { }
21889 Note that when the template is first instantiated, with
21890 instantiate_template, the resulting DECL will have no name for the
21891 first parameter, and the wrong type for the second. So, when we go
21892 to instantiate the DECL, we regenerate it. */
21894 static void
21896 {
21897 /* The arguments used to instantiate DECL, from the most general
21898 template. */
21899 tree code_pattern;
21903 /* Make sure that we can see identifiers, and compute access
21904 correctly. */
21908 {
21909 tree decl_parm;
21910 tree pattern_parm;
21911 tree specs;
21925 specs);
21927 /* Merge parameter declarations. */
21930 pattern_parm
21934 {
21935 tree parm_type;
21936 tree attributes;
21941 NULL_TREE);
21947 {
21950 }
21953 }
21954 /* Merge any parameters that match with the function parameter
21955 pack. */
21957 {
21959 tree expanded_types;
21960 /* Expand the TYPE_PACK_EXPANSION that provides the types for
21961 the parameters in this function parameter pack. */
21966 {
21967 tree parm_type;
21968 tree attributes;
21971 /* Rename the parameter to include the index. */
21980 {
21983 }
21985 }
21986 }
21987 /* Merge additional specifiers from the CODE_PATTERN. */
21991 }
21993 {
22001 }
22002 else
22006 }
22008 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22009 substituted to get DECL. */
22011 tree
22013 {
22016 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22017 for the instantiation. This is not always the most general
22018 template. Consider, for example:
22020 template <class T>
22021 struct S { template <class U> void f();
22022 template <> void f<int>(); };
22024 and an instantiation of S<double>::f<int>. We want TD to be the
22025 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22027 more general template. */
22029 /* We must also deal with friend templates. Given:
22031 template <class T> struct S {
22032 template <class U> friend void f() {};
22033 };
22035 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22036 so far as the language is concerned, but that's still
22037 where we get the pattern for the instantiation from. On
22038 other hand, if the definition comes outside the class, say:
22040 template <class T> struct S {
22041 template <class U> friend void f();
22042 };
22043 template <class U> friend void f() {}
22045 we don't need to look any further. That's what the check for
22046 DECL_INITIAL is for. */
22050 {
22051 /* The present template, TD, should not be a definition. If it
22052 were a definition, we should be using it! Note that we
22053 cannot restructure the loop to just keep going until we find
22054 a template with a definition, since that might go too far if
22055 a specialization was declared, but not defined. */
22057 /* Fetch the more general template. */
22059 }
22062 }
22064 /* Returns true if we need to instantiate this template instance even if we
22065 know we aren't going to emit it. */
22067 bool
22069 {
22070 /* We always instantiate inline functions so that we can inline them. An
22071 explicit instantiation declaration prohibits implicit instantiation of
22072 non-inline functions. With high levels of optimization, we would
22073 normally inline non-inline functions -- but we're not allowed to do
22074 that for "extern template" functions. Therefore, we check
22075 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22079 /* And we need to instantiate static data members so that
22080 their initializers are available in integral constant
22081 expressions. */
22084 }
22086 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22087 instantiate it now, modifying TREE_TYPE (fn). */
22089 void
22091 {
22094 /* Don't instantiate a noexcept-specification from template context. */
22109 {
22113 {
22128 }
22129 else
22133 }
22136 {
22139 else
22141 }
22142 }
22144 /* Produce the definition of D, a _DECL generated from a template. If
22145 DEFER_OK is nonzero, then we don't have to actually do the
22146 instantiation now; we just have to do it sometime. Normally it is
22147 an error if this is an explicit instantiation but D is undefined.
22148 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
22149 explicitly instantiated class template. */
22151 tree
22154 {
22156 tree gen_args;
22157 tree args;
22158 tree td;
22159 tree code_pattern;
22160 tree spec;
22161 tree gen_tmpl;
22168 tree fn_context;
22171 /* This function should only be used to instantiate templates for
22172 functions and static member variables. */
22175 /* A concept is never instantiated. */
22178 /* Variables are never deferred; if instantiation is required, they
22179 are instantiated right away. That allows for better code in the
22180 case that an expression refers to the value of the variable --
22181 if the variable has a constant value the referring expression can
22182 take advantage of that fact. */
22186 /* Don't instantiate cloned functions. Instead, instantiate the
22187 functions they cloned. */
22195 /* D has already been instantiated or explicitly specialized, so
22196 there's nothing for us to do here.
22198 It might seem reasonable to check whether or not D is an explicit
22199 instantiation, and, if so, stop here. But when an explicit
22200 instantiation is deferred until the end of the compilation,
22201 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22202 the instantiation. */
22205 /* Check to see whether we know that this template will be
22206 instantiated in some other file, as with "extern template"
22207 extension. */
22210 /* In general, we do not instantiate such templates. */
22218 /* We should already have the extra args. */
22221 /* And what's in the hash table should match D. */
22225 /* This needs to happen before any tsubsting. */
22231 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22232 for the instantiation. */
22237 {
22238 /* Look up an explicit specialization, if any. */
22242 {
22245 }
22246 }
22250 /* We should never be trying to instantiate a member of a class
22251 template or partial specialization. */
22256 /* In the case of a friend template whose definition is provided
22257 outside the class, we may have too many arguments. Drop the
22258 ones we don't need. The same is true for specializations. */
22259 args = get_innermost_template_args
22263 {
22269 }
22270 else
22271 {
22276 else
22278 }
22280 /* We may be in the middle of deferred access check. Disable it now. */
22283 /* Unless an explicit instantiation directive has already determined
22284 the linkage of D, remember that a definition is available for
22285 this entity. */
22295 /* If D is a member of an explicitly instantiated class template,
22296 and no definition is available, treat it like an implicit
22297 instantiation. */
22300 {
22301 /* Leave linkage flags alone on instantiations with anonymous
22302 visibility. */
22304 {
22307 }
22309 }
22311 /* Defer all other templates, unless we have been explicitly
22312 forbidden from doing so. */
22314 template. */
22315 ! pattern_defined
22316 /* If it's OK to postpone instantiation, do so. */
22317 || defer_ok
22318 /* If this is a static data member that will be defined
22319 elsewhere, we don't want to instantiate the entire data
22320 member, but we do want to instantiate the initializer so that
22321 we can substitute that elsewhere. */
22323 /* Handle here a deleted function too, avoid generating
22324 its body (c++/61080). */
22326 {
22327 /* The definition of the static data member is now required so
22328 we must substitute the initializer. */
22332 {
22333 tree ns;
22334 tree init;
22343 args,
22346 /* If instantiating the initializer involved instantiating this
22347 again, don't call cp_finish_decl twice. */
22349 {
22350 /* Make sure the initializer is still constant, in case of
22351 circular dependency (template/instantiate6.C). */
22352 const_init
22356 LOOKUP_ONLYCONVERTING);
22357 }
22361 }
22363 /* We restore the source position here because it's used by
22364 add_pending_template. */
22370 /* [temp.explicit]
22372 The definition of a non-exported function template, a
22373 non-exported member function template, or a non-exported
22374 member function or static data member of a class template
22375 shall be present in every translation unit in which it is
22376 explicitly instantiated. */
22380 /* If we're in unevaluated context, we just wanted to get the
22381 constant value; this isn't an odr use, so don't queue
22382 a full instantiation. */
22385 /* ??? Historically, we have instantiated inline functions, even
22386 when marked as "extern template". */
22390 }
22391 /* Tell the repository that D is available in this translation unit
22392 -- and see if it is supposed to be instantiated here. */
22394 {
22395 /* In a PCH file, despite the fact that the repository hasn't
22396 requested instantiation in the PCH it is still possible that
22397 an instantiation will be required in a file that includes the
22398 PCH. */
22401 /* Instantiate inline functions so that the inliner can do its
22402 job, even though we'll not be emitting a copy of this
22403 function. */
22406 }
22416 else
22417 {
22422 }
22424 /* Mark D as instantiated so that recursive calls to
22425 instantiate_decl do not try to instantiate it again. */
22428 /* Regenerate the declaration in case the template has been modified
22429 by a subsequent redeclaration. */
22432 /* We already set the file and line above. Reset them now in case
22433 they changed as a result of calling regenerate_decl_from_template. */
22437 {
22438 tree init;
22441 /* Clear out DECL_RTL; whatever was there before may not be right
22442 since we've reset the type of the declaration. */
22446 /* The initializer is placed in DECL_INITIAL by
22447 regenerate_decl_from_template so we don't need to
22448 push/pop_access_scope again here. Pull it out so that
22449 cp_finish_decl can process it. */
22454 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22455 initializer. That function will defer actual emission until
22456 we have a chance to determine linkage. */
22459 /* Enter the scope of D so that access-checking works correctly. */
22472 }
22476 {
22478 tree tmpl_parm;
22479 tree spec_parm;
22482 /* Save away the current list, in case we are instantiating one
22483 template from within the body of another. */
22486 /* Set up the list of local specializations. */
22489 /* Set up context. */
22493 else
22496 /* Some typedefs referenced from within the template code need to be
22497 access checked at template instantiation time, i.e now. These
22498 types were added to the template at parsing time. Let's get those
22499 and perform the access checks then. */
22501 args);
22503 /* Create substitution entries for the parameters. */
22507 {
22511 }
22513 {
22515 {
22518 }
22519 else
22520 {
22521 /* Register the (value) argument pack as a specialization of
22522 TMPL_PARM, then move on. */
22525 }
22526 }
22529 /* Substitute into the body of the function. */
22533 else
22534 {
22539 /* Set the current input_location to the end of the function
22540 so that finish_function knows where we are. */
22541 input_location
22544 /* Remember if we saw an infinite loop in the template. */
22545 current_function_infinite_loop
22547 }
22549 /* We don't need the local specializations any more. */
22553 /* Finish the function. */
22557 else
22558 {
22561 }
22565 }
22567 /* We're not deferring instantiation any more. */
22575 out:
22587 }
22589 /* Run through the list of templates that we wish we could
22590 instantiate, and instantiate any we can. RETRIES is the
22591 number of times we retry pending template instantiation. */
22593 void
22595 {
22599 /* Instantiating templates may trigger vtable generation. This in turn
22600 may require further template instantiations. We place a limit here
22601 to avoid infinite loop. */
22603 {
22607 "template instantiation depth exceeds maximum of %d"
22608 " instantiating %q+D, possibly from virtual table generation"
22612 /* Pretend that we defined it. */
22615 }
22617 do
22618 {
22623 {
22628 {
22629 tree fn;
22632 {
22636 fn;
22644 }
22647 }
22648 else
22649 {
22652 {
22653 instantiation
22659 }
22663 }
22666 /* If INSTANTIATION has been instantiated, then we don't
22667 need to consider it again in the future. */
22669 else
22670 {
22673 }
22676 }
22678 }
22682 }
22684 /* Substitute ARGVEC into T, which is a list of initializers for
22685 either base class or a non-static data member. The TREE_PURPOSEs
22686 are DECLs, and the TREE_VALUEs are the initializer values. Used by
22687 instantiate_decl. */
22689 static tree
22691 {
22695 {
22696 tree decl;
22697 tree init;
22703 {
22704 tree expr;
22705 tree arg;
22707 /* Expand the base class expansion type into separate base
22708 classes. */
22710 tf_warning_or_error,
22711 NULL_TREE);
22715 /* We'll be building separate TREE_LISTs of arguments for
22716 each base. */
22722 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
22723 expand each argument in the TREE_VALUE of t. */
22730 /* VOID_TYPE_NODE is used to indicate
22731 value-initialization. */
22732 {
22735 }
22736 else
22737 {
22738 /* Substitute parameter packs into each argument in the
22739 TREE_LIST. */
22742 {
22743 tree expanded_exprs;
22745 /* Expand the argument. */
22747 expanded_exprs
22749 tf_warning_or_error,
22750 NULL_TREE);
22754 /* Prepend each of the expanded expressions to the
22755 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
22757 {
22762 }
22763 }
22766 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
22767 since we built them backwards. */
22769 {
22772 }
22773 }
22774 }
22777 {
22779 {
22783 }
22784 else
22785 {
22786 tree tmp;
22801 /* If we had an initializer but it instantiated to nothing,
22802 value-initialize the object. This will only occur when
22803 the initializer was a pack expansion where the parameter
22804 packs used in that expansion were of length zero. */
22807 }
22810 {
22814 }
22815 }
22816 }
22818 }
22820 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
22822 static void
22824 {
22829 else
22831 }
22833 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
22834 is the instantiation (which should have been created with
22835 start_enum) and ARGS are the template arguments to use. */
22837 static void
22839 {
22840 tree e;
22846 {
22847 tree value;
22848 tree decl;
22851 /* Note that in a template enum, the TREE_VALUE is the
22852 CONST_DECL, not the corresponding INTEGER_CST. */
22857 /* Give this enumeration constant the correct access. */
22860 /* Actually build the enumerator itself. Here we're assuming that
22861 enumerators can't have dependent attributes. */
22864 }
22874 }
22876 /* DECL is a FUNCTION_DECL that is a template specialization. Return
22877 its type -- but without substituting the innermost set of template
22878 arguments. So, innermost set of template parameters will appear in
22879 the type. */
22881 tree
22883 {
22884 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
22886 }
22888 /* Return truthvalue if we're processing a template different from
22889 the last one involved in diagnostics. */
22890 bool
22892 {
22894 }
22896 /* Remember current template involved in diagnostics. */
22897 void
22899 {
22901 }
22905 {
22907 }
22909 /* Return TRUE if current_function_decl is being instantiated, false
22910 otherwise. */
22912 bool
22914 {
22917 }
22919 /* [temp.param] Check that template non-type parm TYPE is of an allowable
22920 type. Return zero for ok, nonzero for disallowed. Issue error and
22921 warning messages under control of COMPLAIN. */
22923 static int
22925 {
22940 /* A bound template template parm could later be instantiated to have a valid
22941 nontype parm type via an alias template. */
22947 {
22950 else
22952 type);
22953 }
22955 }
22957 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
22958 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
22960 static bool
22962 {
22963 tree scope;
22965 /* [temp.dep.type]
22967 A type is dependent if it is:
22969 -- a template parameter. Template template parameters are types
22970 for us (since TYPE_P holds true for them) so we handle
22971 them here. */
22975 /* -- a qualified-id with a nested-name-specifier which contains a
22976 class-name that names a dependent type or whose unqualified-id
22977 names a dependent type. */
22981 /* An alias template specialization can be dependent even if the
22982 resulting type is not. */
22986 /* -- a cv-qualified type where the cv-unqualified type is
22987 dependent.
22988 No code is necessary for this bullet; the code below handles
22989 cv-qualified types, and we don't want to strip aliases with
22990 TYPE_MAIN_VARIANT because of DR 1558. */
22991 /* -- a compound type constructed from any dependent type. */
23001 {
23002 tree arg_type;
23007 arg_type;
23012 }
23013 /* -- an array type constructed from any dependent type or whose
23014 size is specified by a constant expression that is
23015 value-dependent.
23017 We checked for type- and value-dependence of the bounds in
23018 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23020 {
23025 }
23027 /* -- a template-id in which either the template name is a template
23028 parameter ... */
23031 /* ... or any of the template arguments is a dependent type or
23032 an expression that is type-dependent or value-dependent. */
23034 && (any_dependent_template_arguments_p
23038 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23039 dependent; if the argument of the `typeof' expression is not
23040 type-dependent, then it should already been have resolved. */
23046 /* A template argument pack is dependent if any of its packed
23047 arguments are. */
23049 {
23055 }
23057 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23058 be template parameters. */
23065 /* The standard does not specifically mention types that are local
23066 to template functions or local classes, but they should be
23067 considered dependent too. For example:
23069 template <int I> void f() {
23070 enum E { a = I };
23071 S<sizeof (E)> s;
23072 }
23074 The size of `E' cannot be known until the value of `I' has been
23075 determined. Therefore, `E' must be considered dependent. */
23079 /* Don't use type_dependent_expression_p here, as it can lead
23080 to infinite recursion trying to determine whether a lambda
23081 nested in a lambda is dependent (c++/47687). */
23085 && (any_dependent_template_arguments_p
23089 /* Other types are non-dependent. */
23091 }
23093 /* Returns TRUE if TYPE is dependent, in the sense of
23094 [temp.dep.type]. Note that a NULL type is considered dependent. */
23096 bool
23098 {
23099 /* If there are no template parameters in scope, then there can't be
23100 any dependent types. */
23102 {
23103 /* If we are not processing a template, then nobody should be
23104 providing us with a dependent type. */
23108 }
23110 /* If the type is NULL, we have not computed a type for the entity
23111 in question; in that case, the type is dependent. */
23115 /* Erroneous types can be considered non-dependent. */
23119 /* If we have not already computed the appropriate value for TYPE,
23120 do so now. */
23122 {
23125 }
23128 }
23130 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23131 lookup. In other words, a dependent type that is not the current
23132 instantiation. */
23134 bool
23136 {
23139 }
23141 /* T is a SCOPE_REF; return whether we need to consider it
23142 instantiation-dependent so that we can check access at instantiation
23143 time even though we know which member it resolves to. */
23145 static bool
23147 {
23153 else
23155 }
23157 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23158 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23159 expression. */
23161 /* Note that this predicate is not appropriate for general expressions;
23162 only constant expressions (that satisfy potential_constant_expression)
23163 can be tested for value dependence. */
23165 bool
23167 {
23171 /* A name declared with a dependent type. */
23176 {
23178 /* A dependent member function of the current instantiation. */
23182 /* A dependent member function of the current instantiation. */
23189 /* A name that has not been looked up -- must be dependent. */
23193 /* A non-type template parm. */
23197 /* A non-type template parm. */
23203 /* A constant with literal type and is initialized
23204 with an expression that is value-dependent.
23206 Note that a non-dependent parenthesized initializer will have
23207 already been replaced with its constant value, so if we see
23208 a TREE_LIST it must be dependent. */
23212 /* cp_finish_decl doesn't fold reference initializers. */
23224 /* These expressions are value-dependent if the type to which
23225 the cast occurs is dependent or the expression being casted
23226 is value-dependent. */
23227 {
23233 /* A functional cast has a list of operands. */
23236 {
23237 /* If there are no operands, it must be an expression such
23238 as "int()". This should not happen for aggregate types
23239 because it would form non-constant expressions. */
23244 }
23250 }
23255 /* FALLTHRU */
23258 /* A `sizeof' expression is value-dependent if the operand is
23259 type-dependent or is a pack expansion. */
23268 /* An 'encode' expression is value-dependent if the operand is
23269 type-dependent. */
23278 /* All instantiation-dependent expressions should also be considered
23279 value-dependent. */
23287 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23288 is value-dependent. */
23289 {
23298 }
23301 {
23305 }
23316 {
23320 }
23323 /* Treat all requires-expressions as value-dependent so
23324 we don't try to fold them. */
23331 {
23338 {
23340 /* In a call to a constexpr member function, look through the
23341 implicit ADDR_EXPR on the object argument so that it doesn't
23342 cause the call to be considered value-dependent. We also
23343 look through it in potential_constant_expression. */
23350 }
23352 }
23355 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23356 type-dependent. */
23361 {
23363 tree val;
23370 }
23373 /* Treat a GNU statement expression as dependent to avoid crashing
23374 under instantiate_non_dependent_expr; it can't be constant. */
23378 /* A constant expression is value-dependent if any subexpression is
23379 value-dependent. */
23381 {
23388 {
23392 {
23395 /* In some cases, some of the operands may be missing.l
23396 (For example, in the case of PREDECREMENT_EXPR, the
23397 amount to increment by may be missing.) That doesn't
23398 make the expression dependent. */
23401 }
23402 }
23406 }
23408 }
23410 /* The expression is not value-dependent. */
23412 }
23414 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23415 [temp.dep.expr]. Note that an expression with no type is
23416 considered dependent. Other parts of the compiler arrange for an
23417 expression with type-dependent subexpressions to have no type, so
23418 this function doesn't have to be fully recursive. */
23420 bool
23422 {
23429 /* An unresolved name is always dependent. */
23435 /* A fold expression is type-dependent. */
23442 /* Some expression forms are never type-dependent. */
23456 /* The types of these expressions depends only on the type to which
23457 the cast occurs. */
23466 /* The types of these expressions depends only on the type created
23467 by the expression. */
23470 {
23471 /* For NEW_EXPR tree nodes created inside a template, either
23472 the object type itself or a TREE_LIST may appear as the
23473 operand 1. */
23476 /* This is an array type. We need to check array dimensions
23477 as well. */
23479 || value_dependent_expression_p
23481 else
23483 }
23486 {
23490 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23491 contains an identifier associated by name lookup with one or more
23492 declarations declared with a dependent type, or...a
23493 nested-name-specifier or qualified-id that names a member of an
23494 unknown specialization. */
23497 }
23507 {
23508 tree elt;
23512 {
23515 }
23517 }
23519 /* A static data member of the current instantiation with incomplete
23520 array type is type-dependent, as the definition and specializations
23521 can have different bounds. */
23528 /* An array of unknown bound depending on a variadic parameter, eg:
23530 template<typename... Args>
23531 void foo (Args... args)
23532 {
23533 int arr[] = { args... };
23534 }
23536 template<int... vals>
23537 void bar ()
23538 {
23539 int arr[] = { vals... };
23540 }
23542 If the array has no length and has an initializer, it must be that
23543 we couldn't determine its length in cp_complete_array_type because
23544 it is dependent. */
23551 /* A function or variable template-id is type-dependent if it has any
23552 dependent template arguments. Note that we only consider the innermost
23553 template arguments here, since those are the ones that come from the
23554 template-id; the template arguments for the enclosing class do not make it
23555 type-dependent, they only make a member function value-dependent. */
23560 && (any_dependent_template_arguments_p
23564 /* Always dependent, on the number of arguments if nothing else. */
23569 {
23574 {
23580 }
23581 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23586 {
23591 }
23594 {
23601 }
23607 {
23611 }
23613 }
23617 /* Dependent type attributes might not have made it from the decl to
23618 the type yet. */
23624 }
23626 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23627 type-dependent if the expression refers to a member of the current
23628 instantiation and the type of the referenced member is dependent, or the
23629 class member access expression refers to a member of an unknown
23630 specialization.
23632 This function returns true if the OBJECT in such a class member access
23633 expression is of an unknown specialization. */
23635 bool
23637 {
23640 }
23642 /* walk_tree callback function for instantiation_dependent_expression_p,
23643 below. Returns non-zero if a dependent subexpression is found. */
23645 static tree
23648 {
23650 {
23651 /* We don't have to worry about decltype currently because decltype
23652 of an instantiation-dependent expr is a dependent type. This
23653 might change depending on the resolution of DR 1172. */
23656 }
23659 {
23660 /* Don't treat an argument list as dependent just because it has no
23661 TREE_TYPE. */
23669 /* Handle expressions with type operands. */
23674 {
23679 {
23682 else
23683 {
23686 }
23687 }
23689 }
23693 /* In a template, finish_class_member_access_expr creates a
23694 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
23695 type-dependent, so that we can check access control at
23696 instantiation time (PR 42277). See also Core issue 1273. */
23703 else
23706 /* Treat statement-expressions as dependent. */
23710 /* Treat requires-expressions as dependent. */
23715 /* Treat calls to function concepts as dependent. */
23721 /* And variable concepts. */
23728 }
23732 else
23734 }
23736 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
23737 sense defined by the ABI:
23739 "An expression is instantiation-dependent if it is type-dependent
23740 or value-dependent, or it has a subexpression that is type-dependent
23741 or value-dependent."
23743 Except don't actually check value-dependence for unevaluated expressions,
23744 because in sizeof(i) we don't care about the value of i. Checking
23745 type-dependence will in turn check value-dependence of array bounds/template
23746 arguments as needed. */
23748 bool
23750 {
23751 tree result;
23762 }
23764 /* As above, but also check value-dependence of the expression as a whole. */
23766 bool
23768 {
23771 }
23773 /* Like type_dependent_expression_p, but it also works while not processing
23774 a template definition, i.e. during substitution or mangling. */
23776 bool
23778 {
23784 }
23786 /* Returns TRUE if ARGS contains a type-dependent expression. */
23788 bool
23790 {
23792 tree arg;
23795 {
23798 }
23800 }
23802 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23803 expressions) contains any type-dependent expressions. */
23805 bool
23807 {
23813 }
23815 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23816 expressions) contains any value-dependent expressions. */
23818 bool
23820 {
23826 }
23828 /* Returns TRUE if the ARG (a template argument) is dependent. */
23830 bool
23832 {
23836 /* Assume a template argument that was wrongly written by the user
23837 is dependent. This is consistent with what
23838 any_dependent_template_arguments_p [that calls this function]
23839 does. */
23849 {
23852 /* A member template of a dependent class is not necessarily
23853 type-dependent, but it is a dependent template argument because it
23854 will be a member of an unknown specialization to that template. */
23857 }
23859 {
23863 {
23866 }
23869 }
23872 else
23875 }
23877 /* Returns true if ARGS (a collection of template arguments) contains
23878 any types that require structural equality testing. */
23880 bool
23882 {
23892 {
23895 {
23901 {
23902 /* Look inside the argument pack. */
23905 }
23908 {
23921 }
23922 }
23923 }
23926 }
23928 /* Returns true if ARGS (a collection of template arguments) contains
23929 any dependent arguments. */
23931 bool
23933 {
23943 {
23948 }
23951 }
23953 /* Returns TRUE if the template TMPL is type-dependent. */
23955 bool
23957 {
23959 {
23961 {
23965 }
23967 }
23969 /* Template template parameters are dependent. */
23973 /* So are names that have not been looked up. */
23977 }
23979 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
23981 bool
23983 {
23986 }
23988 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
23989 are dependent. */
23991 bool
23993 {
24000 {
24022 {
24026 }
24030 {
24034 {
24039 }
24040 }
24041 }
24044 }
24046 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24047 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24048 no such TYPE can be found. Note that this function peers inside
24049 uninstantiated templates and therefore should be used only in
24050 extremely limited situations. ONLY_CURRENT_P restricts this
24051 peering to the currently open classes hierarchy (which is required
24052 when comparing types). */
24054 tree
24056 {
24057 tree scope;
24058 tree name;
24059 tree decl;
24061 tree pushed_scope;
24062 tree result;
24067 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24068 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24069 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24070 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24071 identifier of the TYPENAME_TYPE anymore.
24072 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24073 TYPENAME_TYPE instead, we avoid messing up with a possible
24074 typedef variant case. */
24077 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24078 it first before we can figure out what NAME refers to. */
24080 {
24082 /* Given a class template A with a dependent base with nested type C,
24083 typedef typename A::C::C C will land us here, as trying to resolve
24084 the initial A::C leads to the local C typedef, which leads back to
24085 A::C::C. So we break the recursion now. */
24087 else
24089 }
24090 /* If we don't know what SCOPE refers to, then we cannot resolve the
24091 TYPENAME_TYPE. */
24094 /* If this is a typedef, we don't want to look inside (c++/11987). */
24097 /* If SCOPE isn't the template itself, it will not have a valid
24098 TYPE_FIELDS list. */
24100 /* scope is either the template itself or a compatible instantiation
24101 like X<T>, so look up the name in the original template. */
24103 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24105 /* If scope has no fields, it can't be a current instantiation. Check this
24106 before currently_open_class to avoid infinite recursion (71515). */
24109 /* If the SCOPE is not the current instantiation, there's no reason
24110 to look inside it. */
24113 /* Enter the SCOPE so that name lookup will be resolved as if we
24114 were in the class definition. In particular, SCOPE will no
24115 longer be considered a dependent type. */
24117 /* Look up the declaration. */
24119 tf_warning_or_error);
24123 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24124 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24129 {
24133 }
24136 {
24137 tree tmpl;
24138 tree args;
24139 /* Obtain the template and the arguments. */
24142 /* Instantiate the template. */
24148 }
24150 /* Leave the SCOPE. */
24154 /* If we failed to resolve it, return the original typename. */
24158 /* If lookup found a typename type, resolve that too. */
24160 {
24161 /* Ill-formed programs can cause infinite recursion here, so we
24162 must catch that. */
24166 }
24168 /* Qualify the resulting type. */
24174 }
24176 /* EXPR is an expression which is not type-dependent. Return a proxy
24177 for EXPR that can be used to compute the types of larger
24178 expressions containing EXPR. */
24180 tree
24182 {
24183 tree inner_expr;
24185 /* When checking, try to get a constant value for all non-dependent
24186 expressions in order to expose bugs in *_dependent_expression_p
24187 and constexpr. This can affect code generation, see PR70704, so
24188 only do this for -fchecking=2. */
24191 /* Don't do this during nsdmi parsing as it can lead to
24192 unexpected recursive instantiations. */
24194 /* Don't do this during concept expansion either and for
24195 the same reason. */
24199 /* Preserve OVERLOADs; the functions must be available to resolve
24200 types. */
24211 /* There is no need to return a proxy for a variable. */
24214 /* Preserve string constants; conversions from string constants to
24215 "char *" are allowed, even though normally a "const char *"
24216 cannot be used to initialize a "char *". */
24219 /* Preserve void and arithmetic constants, as an optimization -- there is no
24220 reason to create a new node. */
24225 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24226 There is at least one place where we want to know that a
24227 particular expression is a throw-expression: when checking a ?:
24228 expression, there are special rules if the second or third
24229 argument is a throw-expression. */
24233 /* Don't wrap an initializer list, we need to be able to look inside. */
24237 /* Don't wrap a dummy object, we need to be able to test for it. */
24256 /* If the type is unknown, it can't really be non-dependent */
24259 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24261 }
24263 /* ARGS is a vector of expressions as arguments to a function call.
24264 Replace the arguments with equivalent non-dependent expressions.
24265 This modifies ARGS in place. */
24267 void
24269 {
24271 tree arg;
24274 {
24278 }
24279 }
24281 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24282 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24283 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24285 static tree
24287 {
24301 }
24303 tree
24305 {
24307 }
24309 tree
24311 {
24313 }
24315 /* Return a C++17 deduction placeholder for class template TMPL. */
24317 tree
24319 {
24323 }
24325 /* Make a "constrained auto" type-specifier. This is an
24326 auto type with constraints that must be associated after
24327 deduction. The constraint is formed from the given
24328 CONC and its optional sequence of arguments, which are
24329 non-null if written as partial-concept-id. */
24331 tree
24333 {
24336 /* Build the constraint. */
24338 tree expr;
24341 else
24347 /* Our canonical type depends on the constraint. */
24350 /* Attach the constraint to the type declaration. */
24353 }
24355 /* Given type ARG, return std::initializer_list<ARG>. */
24357 static tree
24359 {
24360 tree std_init_list = namespace_binding
24362 tree argvec;
24364 {
24368 }
24373 }
24375 /* Replace auto in TYPE with std::initializer_list<auto>. */
24377 static tree
24379 {
24386 }
24388 /* Hash traits for hashing possibly constrained 'auto'
24389 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24392 {
24395 };
24397 /* Hash the 'auto' T. */
24399 inline hashval_t
24401 {
24403 /* Matching constrained-type-specifiers denote the same template
24404 parameter, so hash the constraint. */
24406 else
24407 /* But unconstrained autos are all separate, so just hash the pointer. */
24409 }
24411 /* Compare two 'auto's. */
24415 {
24422 /* Two unconstrained autos are distinct. */
24427 }
24429 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24430 constrained) auto, add it to the vector. */
24432 static int
24434 {
24437 {
24438 /* All the autos were built with index 0; fix that up now. */
24442 /* If this is a repeated constrained-type-specifier, use the index we
24443 chose before. */
24445 else
24446 {
24447 /* Otherwise this is new, so use the current count. */
24450 }
24452 }
24454 /* Always keep walking. */
24456 }
24458 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24459 says they can appear anywhere in the type. */
24461 static tree
24463 {
24472 {
24477 }
24480 }
24482 /* The stem for deduction guide names. */
24485 /* Return the name for a deduction guide for class template TMPL. */
24487 tree
24489 {
24500 }
24502 /* True if NAME is the name of a deduction guide. */
24504 bool
24506 {
24510 }
24512 /* True if FN is a deduction guide. */
24514 bool
24516 {
24520 }
24522 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24523 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24524 template parameter types. Note that the handling of template template
24525 parameters relies on current_template_parms being set appropriately for the
24526 new template. */
24528 static tree
24531 {
24534 tree newtype;
24537 {
24540 }
24541 else
24545 tree newdecl
24550 tree newidx;
24553 {
24561 {
24566 // First create a copy (ttargs) of tsubst_args with an
24567 // additional level for the template template parameter's own
24568 // template parameters (ttparms).
24569 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24577 // Substitute ttargs into ttparms to fix references to
24578 // other template parameters.
24580 complain);
24581 // Now substitute again with args based on tparms, to reduce
24582 // the level of the ttparms.
24585 complain);
24586 // Finally, tack the adjusted parms onto tparms.
24588 current_template_parms);
24590 }
24591 }
24592 else
24593 {
24595 tree newconst
24605 }
24610 }
24612 /* Returns a C++17 class deduction guide template based on the constructor
24613 CTOR. */
24615 static tree
24617 {
24621 tree fn_tmpl;
24623 {
24626 }
24627 else
24631 /* If type is a member class template, DECL_TI_ARGS (ctor) will have fully
24632 specialized args for the enclosing class. Strip those off, as the
24633 deduction guide won't have those template parameters. */
24636 /* Discard the 'this' parameter. */
24642 {
24643 /* For a member template constructor, we need to flatten the two template
24644 parameter lists into one, and then adjust the function signature
24645 accordingly. This gets...complicated. */
24649 /* For a member template we should have two levels of parms/args, one for
24650 the class and one for the constructor. We stripped specialized args
24651 for further enclosing classes above. */
24655 /* Template args for translating references to the two-level template
24656 parameters into references to the one-level template parameters we are
24657 creating. */
24662 /* Template parms for the constructor template. */
24665 /* Template parms for the class template. */
24669 /* Template parms for the deduction guide start as a copy of the template
24670 parms for the class. We set current_template_parms for
24671 lookup_template_class_1. */
24677 /* Now we need to rewrite the constructor parms to append them to the
24678 class parms. */
24680 {
24695 }
24697 /* Now we have a final set of template parms to substitute into the
24698 function signature. */
24708 }
24712 FUNCTION_DECL,
24723 }
24725 /* Deduce template arguments for the class template placeholder PTYPE for
24726 template TMPL based on the initializer INIT, and return the resulting
24727 type. */
24729 tree
24731 {
24733 {
24734 /* We should have handled this in the caller. */
24740 }
24749 else
24753 {
24754 /* First try to deduce directly, since we don't have implicitly-declared
24755 constructors yet. */
24764 }
24776 {
24779 }
24782 // FIXME cache artificial deduction guides
24784 {
24788 }
24791 {
24795 }
24804 }
24806 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24807 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
24809 tree
24811 {
24813 tf_warning_or_error,
24814 adc_unspecified);
24815 }
24817 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24818 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
24819 The CONTEXT determines the context in which auto deduction is performed
24820 and is used to control error diagnostics.
24822 For partial-concept-ids, extra args may be appended to the list of deduced
24823 template arguments prior to determining constraint satisfaction. */
24825 tree
24828 tree outer_targs)
24829 {
24830 tree targs;
24837 /* Defining a subset of type-dependent expressions that we can deduce
24838 from ahead of time isn't worth the trouble. */
24842 /* C++17 class template argument deduction. */
24845 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
24846 with either a new invented type template parameter U or, if the
24847 initializer is a braced-init-list (8.5.4), with
24848 std::initializer_list<U>. */
24850 {
24855 else
24856 {
24858 {
24862 "for deduction to %<std::initializer_list%>, use copy-"
24864 }
24866 }
24867 }
24878 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
24879 and initializer has array type, deduce cv-qualified array type. */
24881 complain);
24883 {
24892 {
24896 }
24897 }
24898 else
24899 {
24901 tree tparms;
24905 else
24906 {
24910 }
24917 {
24919 /* Try again at instantiation time. */
24923 /* If type is error_mark_node a diagnostic must have been
24924 emitted by now. Also, having a mention to '<type error>'
24925 in the diagnostic is not really useful to the user. */
24926 {
24930 else
24935 }
24937 }
24938 }
24940 /* Check any placeholder constraints against the deduced type. */
24943 {
24944 /* Use the deduced type to check the associated constraints. If we
24945 have a partial-concept-id, rebuild the argument list so that
24946 we check using the extra arguments. */
24950 {
24953 }
24954 else
24957 {
24959 {
24961 {
24979 }
24981 }
24983 }
24984 }
24990 }
24992 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
24993 result. */
24995 tree
24997 {
24999 {
25005 /* In an abbreviated function template we didn't know we were dealing
25006 with a function template when we saw the auto return type, so update
25007 it to have the correct level. */
25009 }
25011 }
25013 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25014 'decltype(auto)' or a deduced class template. */
25016 bool
25018 {
25024 else
25026 }
25028 /* for_each_template_parm callback for type_uses_auto. */
25030 int
25032 {
25034 }
25036 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25037 a use of `auto'. Returns NULL_TREE otherwise. */
25039 tree
25041 {
25045 {
25046 /* The Concepts TS allows multiple autos in one type-specifier; just
25047 return the first one we find, do_auto_deduction will collect all of
25048 them. */
25052 else
25054 }
25055 else
25057 }
25059 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25060 'decltype(auto)' or a concept. */
25062 bool
25064 {
25066 }
25068 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25069 a concept identifier) iff TYPE contains a use of a generic type. Returns
25070 NULL_TREE otherwise. */
25072 tree
25074 {
25076 }
25079 /* For a given template T, return the vector of typedefs referenced
25080 in T for which access check is needed at T instantiation time.
25081 T is either a FUNCTION_DECL or a RECORD_TYPE.
25082 Those typedefs were added to T by the function
25083 append_type_to_template_for_access_check. */
25087 {
25088 tree ti;
25099 {
25104 }
25107 }
25109 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25110 tied to T. That list of typedefs will be access checked at
25111 T instantiation time.
25112 T is either a FUNCTION_DECL or a RECORD_TYPE.
25113 TYPE_DECL is a TYPE_DECL node representing a typedef.
25114 SCOPE is the scope through which TYPE_DECL is accessed.
25115 LOCATION is the location of the usage point of TYPE_DECL.
25117 This function is a subroutine of
25118 append_type_to_template_for_access_check. */
25120 static void
25122 tree type_decl,
25123 tree scope,
25124 location_t location)
25125 {
25126 qualified_typedef_usage_t typedef_usage;
25127 tree ti;
25134 && type_decl
25148 }
25150 /* Append TYPE_DECL to the template TEMPL.
25151 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25152 At TEMPL instanciation time, TYPE_DECL will be checked to see
25153 if it can be accessed through SCOPE.
25154 LOCATION is the location of the usage point of TYPE_DECL.
25156 e.g. consider the following code snippet:
25158 class C
25159 {
25160 typedef int myint;
25161 };
25163 template<class U> struct S
25164 {
25165 C::myint mi; // <-- usage point of the typedef C::myint
25166 };
25168 S<char> s;
25170 At S<char> instantiation time, we need to check the access of C::myint
25171 In other words, we need to check the access of the myint typedef through
25172 the C scope. For that purpose, this function will add the myint typedef
25173 and the scope C through which its being accessed to a list of typedefs
25174 tied to the template S. That list will be walked at template instantiation
25175 time and access check performed on each typedefs it contains.
25176 Note that this particular code snippet should yield an error because
25177 myint is private to C. */
25179 void
25181 tree type_decl,
25182 tree scope,
25183 location_t location)
25184 {
25190 /* Make sure we don't append the type to the template twice. */
25197 }
25199 /* Convert the generic type parameters in PARM that match the types given in the
25200 range [START_IDX, END_IDX) from the current_template_parms into generic type
25201 packs. */
25203 tree
25205 {
25216 {
25217 /* Create a distinct parameter pack type from the current parm and add it
25218 to the replacement args to tsubst below into the generic function
25219 parameter. */
25234 }
25240 /* If there are more levels then build up the replacement with the outer
25241 template parms. */
25245 replacement);
25248 }
25250 /* Entries in the decl_constraint hash table. */
25252 {
25253 tree decl;
25254 tree ci;
25255 };
25257 /* Hashing function and equality for constraint entries. */
25259 {
25261 {
25263 }
25266 {
25268 }
25269 };
25271 /* A mapping from declarations to constraint information. Note that
25272 both templates and their underlying declarations are mapped to the
25273 same constraint information.
25275 FIXME: This is defined in pt.c because garbage collection
25276 code is not being generated for constraint.cc. */
25280 /* Returns the template constraints of declaration T. If T is not
25281 constrained, return NULL_TREE. Note that T must be non-null. */
25283 tree
25285 {
25296 else
25298 }
25300 /* Associate the given constraint information CI with the declaration
25301 T. If T is a template, then the constraints are associated with
25302 its underlying declaration. Don't build associations if CI is
25303 NULL_TREE. */
25305 void
25307 {
25319 }
25321 /* Remove the associated constraints of the declaration T. */
25323 void
25325 {
25334 }
25336 /* Memoized satisfaction results for declarations. This
25337 maps the pair (constraint_info, arguments) to the result computed
25338 by constraints_satisfied_p. */
25341 {
25342 tree ci;
25343 tree args;
25344 tree result;
25345 };
25347 /* Hashing function and equality for constraint entries. */
25350 {
25352 {
25355 }
25358 {
25360 }
25361 };
25363 /* Memoized satisfaction results for concept checks. */
25366 {
25367 tree tmpl;
25368 tree args;
25369 tree result;
25370 };
25372 /* Hashing function and equality for constraint entries. */
25375 {
25377 {
25379 }
25382 {
25387 }
25388 };
25393 /* Search for a memoized satisfaction result. Returns one of the
25394 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25396 tree
25398 {
25403 else
25405 }
25407 /* Memoize the result of a satisfication test. Returns the saved result. */
25409 tree
25411 {
25418 }
25420 /* Search for a memoized satisfaction result for a concept. */
25422 tree
25424 {
25429 else
25431 }
25433 /* Memoize the result of a concept check. Returns the saved result. */
25435 tree
25437 {
25444 }
25448 /* Returns a prior concept specialization. This returns the substituted
25449 and normalized constraints defined by the concept. */
25451 tree
25453 {
25458 else
25460 }
25462 /* Save a concept expansion for later. */
25464 tree
25466 {
25473 }
25475 static hashval_t
25477 {
25486 }
25488 /* Compare the constraints of two subsumption entries. The LEFT1 and
25489 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25490 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25492 static bool
25494 {
25502 }
25504 /* Key/value pair for learning and memoizing subsumption results. This
25505 associates a pair of check constraints (including arguments) with
25506 a boolean value indicating the result. */
25509 {
25510 tree t1;
25511 tree t2;
25513 };
25515 /* Hashing function and equality for constraint entries. */
25518 {
25520 {
25522 }
25525 {
25530 }
25531 };
25535 /* Search for a previously cached subsumption result. */
25539 {
25544 else
25546 }
25548 /* Save a subsumption result. */
25550 bool
25552 {
25559 }
25561 /* Set up the hash table for constraint association. */
25563 void
25565 {
25574 }
25576 /* Set up the hash tables for template instantiations. */
25578 void
25580 {
25583 }
25585 /* Print stats about the template hash tables for -fstats. */
25587 void
25589 {
25598 }