| blob | f290cb32fc28b8257de010c77426b85628bbb86b |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
54 {
57 };
72 /* Live only within one (recursive) call to tsubst_expr. We use
73 this to pass the statement expression node from the STMT_EXPR
74 to the EXPR_STMT that is its result. */
77 // -------------------------------------------------------------------------- //
78 // Local Specialization Stack
79 //
80 // Implementation of the RAII helper for creating new local
81 // specializations.
84 {
87 else
89 }
92 {
95 }
97 /* True if we've recursed into fn_type_unification too many times. */
101 {
102 tree tmpl;
103 tree args;
104 tree spec;
105 };
108 {
111 };
117 /* Contains canonical template parameter types. The vector is indexed by
118 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
119 TREE_LIST, whose TREE_VALUEs contain the canonical template
120 parameters of various types and levels. */
123 #define UNIFY_ALLOW_NONE 0
124 #define UNIFY_ALLOW_MORE_CV_QUAL 1
125 #define UNIFY_ALLOW_LESS_CV_QUAL 2
126 #define UNIFY_ALLOW_DERIVED 4
127 #define UNIFY_ALLOW_INTEGER 8
128 #define UNIFY_ALLOW_OUTER_LEVEL 16
129 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
130 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
133 tbr_incomplete_type,
134 tbr_ambiguous_baseclass,
135 tbr_success
136 };
161 tree);
218 location_t);
230 /* Make the current scope suitable for access checking when we are
231 processing T. T can be FUNCTION_DECL for instantiated function
232 template, VAR_DECL for static member variable, or TYPE_DECL for
233 alias template (needed by instantiate_decl). */
235 static void
237 {
245 else
249 {
250 saved_access_scope = tree_cons
253 }
254 }
256 /* Restore the scope set up by push_access_scope. T is the node we
257 are processing. */
259 static void
261 {
263 {
266 }
270 else
272 }
274 /* Do any processing required when DECL (a member template
275 declaration) is finished. Returns the TEMPLATE_DECL corresponding
276 to DECL, unless it is a specialization, in which case the DECL
277 itself is returned. */
279 tree
281 {
288 {
289 tree type;
297 {
301 }
303 }
307 {
309 {
312 }
313 else
315 }
316 else
320 }
322 /* Create a template info node. */
324 tree
326 {
331 }
333 /* Return the template info node corresponding to T, whatever T is. */
335 tree
337 {
359 }
361 /* Returns the template nesting level of the indicated class TYPE.
363 For example, in:
364 template <class T>
365 struct A
366 {
367 template <class U>
368 struct B {};
369 };
371 A<T>::B<U> has depth two, while A<T> has depth one.
372 Both A<T>::B<int> and A<int>::B<U> have depth one, if
373 they are instantiations, not specializations.
375 This function is guaranteed to return 0 if passed NULL_TREE so
376 that, for example, `template_class_depth (current_class_type)' is
377 always safe. */
379 int
381 {
385 {
396 else
398 }
401 }
403 /* Subroutine of maybe_begin_member_template_processing.
404 Returns true if processing DECL needs us to push template parms. */
406 static bool
408 {
414 }
416 /* Subroutine of maybe_begin_member_template_processing.
417 Push the template parms in PARMS, starting from LEVELS steps into the
418 chain, and ending at the beginning, since template parms are listed
419 innermost first. */
421 static void
423 {
431 current_template_parms
437 NULL);
439 {
448 {
455 /* Push the CONST_DECL. */
461 }
462 }
463 }
465 /* Restore the template parameter context for a member template, a
466 friend template defined in a class definition, or a non-template
467 member of template class. */
469 void
471 {
472 tree parms;
477 {
480 /* Disregard full specializations (c++/60999). */
483 }
486 {
491 {
494 }
497 }
499 /* Remember how many levels of template parameters we pushed so that
500 we can pop them later. */
502 }
504 /* Undo the effects of maybe_begin_member_template_processing. */
506 void
508 {
517 {
521 }
522 }
524 /* Return a new template argument vector which contains all of ARGS,
525 but has as its innermost set of arguments the EXTRA_ARGS. */
527 static tree
529 {
530 tree new_args;
548 }
550 /* Like add_to_template_args, but only the outermost ARGS are added to
551 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
552 (EXTRA_ARGS) levels are added. This function is used to combine
553 the template arguments from a partial instantiation with the
554 template arguments used to attain the full instantiation from the
555 partial instantiation. */
557 static tree
559 {
560 tree new_args;
562 /* If there are more levels of EXTRA_ARGS than there are ARGS,
563 something very fishy is going on. */
566 /* If *all* the new arguments will be the EXTRA_ARGS, just return
567 them. */
571 /* For the moment, we make ARGS look like it contains fewer levels. */
576 /* Now, we restore ARGS to its full dimensions. */
580 }
582 /* Return the N levels of innermost template arguments from the ARGS. */
584 tree
586 {
587 tree new_args;
593 /* If N is 1, just return the innermost set of template arguments. */
597 /* If we're not removing anything, just return the arguments we were
598 given. */
604 /* Make a new set of arguments, not containing the outer arguments. */
611 }
613 /* The inverse of get_innermost_template_args: Return all but the innermost
614 EXTRA_LEVELS levels of template arguments from the ARGS. */
616 static tree
618 {
619 tree new_args;
625 /* If N is 1, just return the outermost set of template arguments. */
629 /* If we're not removing anything, just return the arguments we were
630 given. */
635 /* Make a new set of arguments, not containing the inner arguments. */
642 }
644 /* We've got a template header coming up; push to a new level for storing
645 the parms. */
647 void
649 {
650 /* We use a non-tag-transparent scope here, which causes pushtag to
651 put tags in this scope, rather than in the enclosing class or
652 namespace scope. This is the right thing, since we want
653 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
654 global template class, push_template_decl handles putting the
655 TEMPLATE_DECL into top-level scope. For a nested template class,
656 e.g.:
658 template <class T> struct S1 {
659 template <class T> struct S2 {};
660 };
662 pushtag contains special code to insert the TEMPLATE_DECL for S2
663 at the right scope. */
669 /* Add a dummy parameter level while we process the parameter list. */
670 current_template_parms
673 current_template_parms);
674 }
676 /* This routine is called when a specialization is declared. If it is
677 invalid to declare a specialization here, an error is reported and
678 false is returned, otherwise this routine will return true. */
680 static bool
682 {
685 /* [temp.expl.spec]
687 An explicit specialization shall be declared in the namespace of
688 which the template is a member, or, for member templates, in the
689 namespace of which the enclosing class or enclosing class
690 template is a member. An explicit specialization of a member
691 function, member class or static data member of a class template
692 shall be declared in the namespace of which the class template
693 is a member. */
695 {
698 }
700 /* [temp.expl.spec]
702 In an explicit specialization declaration for a member of a class
703 template or a member template that appears in namespace scope,
704 the member template and some of its enclosing class templates may
705 remain unspecialized, except that the declaration shall not
706 explicitly specialize a class member template if its enclosing
707 class templates are not explicitly specialized as well. */
709 {
712 }
715 }
717 /* We've just seen template <>. */
719 bool
721 {
725 }
727 /* Called at then end of processing a declaration preceded by
728 template<>. */
730 void
732 {
735 }
737 /* Any template <>'s that we have seen thus far are not referring to a
738 function specialization. */
740 void
742 {
745 }
747 /* We've just seen a template header. If SPECIALIZATION is nonzero,
748 it was of the form template <>. */
750 static void
752 {
754 template_header_count++;
755 }
757 /* We're beginning an explicit instantiation. */
759 void
761 {
764 }
767 void
769 {
772 }
774 /* An explicit specialization or partial specialization of TMPL is being
775 declared. Check that the namespace in which the specialization is
776 occurring is permissible. Returns false iff it is invalid to
777 specialize TMPL in the current namespace. */
779 static bool
781 {
784 /* [tmpl.expl.spec]
786 An explicit specialization shall be declared in a namespace enclosing the
787 specialized template. An explicit specialization whose declarator-id is
788 not qualified shall be declared in the nearest enclosing namespace of the
789 template, or, if the namespace is inline (7.3.1), any namespace from its
790 enclosing namespace set. */
793 {
796 }
799 /* Same or enclosing namespace. */
801 else
802 {
803 auto_diagnostic_group d;
809 }
810 }
812 /* SPEC is an explicit instantiation. Check that it is valid to
813 perform this explicit instantiation in the current namespace. */
815 static void
817 {
818 tree ns;
820 /* DR 275: An explicit instantiation shall appear in an enclosing
821 namespace of its template. */
827 }
829 // Returns the type of a template specialization only if that
830 // specialization needs to be defined. Otherwise (e.g., if the type has
831 // already been defined), the function returns NULL_TREE.
832 static tree
834 {
835 // An implicit instantiation of an incomplete type implies
836 // the definition of a new class template.
837 //
838 // template<typename T>
839 // struct S;
840 //
841 // template<typename T>
842 // struct S<T*>;
843 //
844 // Here, S<T*> is an implicit instantiation of S whose type
845 // is incomplete.
849 // It can also be the case that TYPE is a completed specialization.
850 // Continuing the previous example, suppose we also declare:
851 //
852 // template<typename T>
853 // requires Integral<T>
854 // struct S<T*>;
855 //
856 // Here, S<T*> refers to the specialization S<T*> defined
857 // above. However, we need to differentiate definitions because
858 // we intend to define a new partial specialization. In this case,
859 // we rely on the fact that the constraints are different for
860 // this declaration than that above.
861 //
862 // Note that we also get here for injected class names and
863 // late-parsed template definitions. We must ensure that we
864 // do not create new type declarations for those cases.
866 {
870 // If there are no template parameters, this cannot be a new
871 // partial template specializtion?
875 // The injected-class-name is not a new partial specialization.
879 // If the constraints are not the same as those of the primary
880 // then, we can probably create a new specialization.
884 {
888 }
890 // Also, if there's a pre-existing specialization with matching
891 // constraints, then this also isn't new.
894 {
902 }
904 // Create a new type node (and corresponding type decl)
905 // for the newly declared specialization.
910 /* We only need a separate type node for storing the definition of this
911 partial specialization; uses of S<T*> are unconstrained, so all are
912 equivalent. So keep TYPE_CANONICAL the same. */
915 // Build the corresponding type decl.
921 }
924 }
926 /* The TYPE is being declared. If it is a template type, that means it
927 is a partial specialization. Do appropriate error-checking. */
929 tree
931 {
932 tree context;
937 /* A lambda that appears in specialization context is not itself a
938 specialization. */
943 {
947 }
952 {
958 else
961 }
963 {
964 /* This is for ordinary explicit specialization and partial
965 specialization of a template class such as:
967 template <> class C<int>;
969 or:
971 template <class T> class C<T*>;
973 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
976 {
983 {
988 }
989 }
995 /* Trying to define a specialization either without a template<> header
996 or in an inappropriate place. We've already given an error, so just
997 bail now so we don't actually define the specialization. */
999 }
1005 {
1006 /* This is for an explicit specialization of member class
1007 template according to [temp.expl.spec/18]:
1009 template <> template <class U> class C<int>::D;
1011 The context `C<int>' must be an implicit instantiation.
1012 Otherwise this is just a member class template declared
1013 earlier like:
1015 template <> class C<int> { template <class U> class D; };
1016 template <> template <class U> class C<int>::D;
1018 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1019 while in the second case, `C<int>::D' is a primary template
1020 and `C<T>::D' may not exist. */
1024 {
1025 tree t;
1030 {
1035 }
1037 /* Check for invalid specialization after instantiation:
1039 template <> template <> class C<int>::D<int>;
1040 template <> template <class U> class C<int>::D; */
1044 {
1048 {
1049 /* We already have a full specialization of this partial
1050 instantiation, or a full specialization has been
1051 looked up but not instantiated. Reassign it to the
1052 new member specialization template. */
1053 spec_entry elt;
1065 spec_entry **slot
1070 }
1071 else
1072 /* But if we've had an implicit instantiation, that's a
1073 problem ([temp.expl.spec]/6). */
1076 }
1078 /* Mark TYPE as a specialization. And as a result, we only
1079 have one level of template argument for the innermost
1080 class template. */
1085 }
1086 }
1088 {
1089 /* Someday C++0x may allow for enum template specialization. */
1094 else
1095 {
1098 }
1099 }
1102 }
1104 /* Returns nonzero if we can optimize the retrieval of specializations
1105 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1106 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1110 {
1113 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1114 parameter. */
1116 /* The optimized lookup depends on the fact that the
1117 template arguments for the member function template apply
1118 purely to the containing class, which is not true if the
1119 containing class is an explicit or partial
1120 specialization. */
1124 /* It is possible to have a template that is not a member
1125 template and is not a member of a template class:
1127 template <typename T>
1128 struct S { friend A::f(); };
1130 Here, the friend function is a template, but the context does
1131 not have template information. The optimized lookup relies
1132 on having ARGS be the template arguments for both the class
1133 and the function template. */
1135 }
1137 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1138 gone through coerce_template_parms by now. */
1140 static void
1142 {
1144 {
1153 /* Allow typedefs on the type of a non-type argument, since a
1155 else
1157 }
1158 }
1160 static void
1162 {
1167 }
1169 /* Retrieve the specialization (in the sense of [temp.spec] - a
1170 specialization is either an instantiation or an explicit
1171 specialization) of TMPL for the given template ARGS. If there is
1172 no such specialization, return NULL_TREE. The ARGS are a vector of
1173 arguments, or a vector of vectors of arguments, in the case of
1174 templates with more than one level of parameters.
1176 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1177 then we search for a partial specialization matching ARGS. This
1178 parameter is ignored if TMPL is not a class template.
1180 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1181 result is a NONTYPE_ARGUMENT_PACK. */
1183 static tree
1185 {
1195 /* There should be as many levels of arguments as there are
1196 levels of parameters. */
1205 /* Lambda functions in templates aren't instantiated normally, but through
1206 tsubst_lambda_expr. */
1211 {
1212 /* The template arguments actually apply to the containing
1213 class. Find the class specialization with those
1214 arguments. */
1216 tree class_specialization
1221 /* Find the instance of TMPL. */
1224 {
1227 /* using-declarations can add base methods to the method vec,
1228 and we don't want those here. */
1231 }
1233 }
1234 else
1235 {
1237 spec_entry elt;
1246 else
1254 }
1257 }
1259 /* Like retrieve_specialization, but for local declarations. */
1261 tree
1263 {
1269 }
1271 /* Returns nonzero iff DECL is a specialization of TMPL. */
1273 int
1275 {
1276 tree t;
1279 {
1285 }
1286 else
1287 {
1296 }
1299 }
1301 /* Returns nonzero iff DECL is a specialization of friend declaration
1302 FRIEND_DECL according to [temp.friend]. */
1304 bool
1306 {
1313 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1314 of a template class, we want to check if DECL is a specialization
1315 if this. */
1319 {
1320 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1323 }
1328 /* There is nothing to do if this is not a template friend. */
1335 /* [temp.friend/6]
1336 A member of a class template may be declared to be a friend of a
1337 non-template class. In this case, the corresponding member of
1338 every specialization of the class template is a friend of the
1339 class granting friendship.
1341 For example, given a template friend declaration
1343 template <class T> friend void A<T>::f();
1345 the member function below is considered a friend
1347 template <> struct A<int> {
1348 void f();
1349 };
1351 For this type of template friend, TEMPLATE_DEPTH below will be
1352 nonzero. To determine if DECL is a friend of FRIEND, we first
1353 check if the enclosing class is a specialization of another. */
1360 {
1361 /* Next, we check the members themselves. In order to handle
1362 a few tricky cases, such as when FRIEND_DECL's are
1364 template <class T> friend void A<T>::g(T t);
1365 template <class T> template <T t> friend void A<T>::h();
1367 and DECL's are
1369 void A<int>::g(int);
1370 template <int> void A<int>::h();
1372 we need to figure out ARGS, the template arguments from
1373 the context of DECL. This is required for template substitution
1374 of `T' in the function parameter of `g' and template parameter
1375 of `h' in the above examples. Here ARGS corresponds to `int'. */
1382 {
1384 {
1387 else
1389 current_depth++;
1390 }
1392 }
1395 {
1397 tree friend_type;
1398 tree decl_type;
1399 tree friend_args_type;
1400 tree decl_args_type;
1402 /* Make sure that both DECL and FRIEND_DECL are templates or
1403 non-templates. */
1409 {
1410 /* If both are templates, check template parameter list. */
1411 tree friend_parms
1416 friend_parms))
1420 }
1421 else
1429 /* Check if return types match. */
1433 /* Check if function parameter types match, ignoring the
1434 `this' parameter. */
1443 }
1444 else
1445 {
1446 /* DECL is a TYPE_DECL */
1450 /* Make sure that both DECL and FRIEND_DECL are templates or
1451 non-templates. */
1452 is_template
1459 {
1460 tree friend_parms;
1461 /* If both are templates, check the name of the two
1462 TEMPLATE_DECL's first because is_friend didn't. */
1467 /* Now check template parameter list. */
1468 friend_parms
1471 return comp_template_parms
1473 friend_parms);
1474 }
1475 else
1478 }
1479 }
1481 }
1483 /* Register the specialization SPEC as a specialization of TMPL with
1484 the indicated ARGS. IS_FRIEND indicates whether the specialization
1485 is actually just a friend declaration. ATTRLIST is the list of
1486 attributes that the specialization is declared with or NULL when
1487 it isn't. Returns SPEC, or an equivalent prior declaration, if
1488 available.
1490 We also store instantiations of field packs in the hash table, even
1491 though they are not themselves templates, to make lookup easier. */
1493 static tree
1495 hashval_t hash)
1496 {
1497 tree fn;
1499 spec_entry elt;
1507 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1508 register it; we want the corresponding TEMPLATE_DECL instead.
1509 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1510 the more obvious `uses_template_parms (spec)' to avoid problems
1511 with default function arguments. In particular, given
1512 something like this:
1514 template <class T> void f(T t1, T t = T())
1516 the default argument expression is not substituted for in an
1517 instantiation unless and until it is actually needed. */
1521 /* We don't put these specializations in the hash table, but we might
1522 want to give an error about a mismatch. */
1524 else
1525 {
1533 slot =
1537 else
1539 }
1541 /* We can sometimes try to re-register a specialization that we've
1542 already got. In particular, regenerate_decl_from_template calls
1543 duplicate_decls which will update the specialization list. But,
1544 we'll still get called again here anyhow. It's more convenient
1545 to simply allow this than to try to prevent it. */
1549 {
1551 {
1554 {
1556 fn);
1558 }
1559 else
1560 {
1561 tree clone;
1562 /* This situation should occur only if the first
1563 specialization is an implicit instantiation, the
1564 second is an explicit specialization, and the
1565 implicit instantiation has not yet been used. That
1566 situation can occur if we have implicitly
1567 instantiated a member function and then specialized
1568 it later.
1570 We can also wind up here if a friend declaration that
1571 looked like an instantiation turns out to be a
1572 specialization:
1574 template <class T> void foo(T);
1575 class S { friend void foo<>(int) };
1576 template <> void foo(int);
1578 We transform the existing DECL in place so that any
1579 pointers to it become pointers to the updated
1580 declaration.
1582 If there was a definition for the template, but not
1583 for the specialization, we want this to look as if
1584 there were no definition, and vice versa. */
1587 /* The call to duplicate_decls will have applied
1588 [temp.expl.spec]:
1590 An explicit specialization of a function template
1591 is inline only if it is explicitly declared to be,
1592 and independently of whether its function template
1593 is.
1595 to the primary function; now copy the inline bits to
1596 the various clones. */
1598 {
1605 }
1609 }
1610 }
1612 {
1615 /* We've already complained in duplicate_decls. */
1619 /* Dup decl failed, but this is a new definition. Set the
1620 line number so any errors match this new
1621 definition. */
1625 }
1626 }
1630 /* A specialization must be declared in the same namespace as the
1631 template it is specializing. */
1637 {
1646 /* If TMPL is a forward declaration of a template function, keep a list
1647 of all specializations in case we need to reassign them to a friend
1648 template later in tsubst_friend_function.
1650 Also keep a list of all variable template instantiations so that
1651 process_partial_specialization can check whether a later partial
1652 specialization would have used it. */
1655 }
1658 }
1660 /* Returns true iff two spec_entry nodes are equivalent. */
1664 bool
1666 {
1673 /* tmpl could be a FIELD_DECL for a capture pack. */
1677 {
1678 /* Partial specializations of a variable template can be distinguished by
1679 constraints. */
1683 }
1687 }
1689 /* Returns a hash for a template TMPL and template arguments ARGS. */
1691 static hashval_t
1693 {
1696 }
1698 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1699 ignoring SPEC. */
1701 hashval_t
1703 {
1705 }
1707 /* Recursively calculate a hash value for a template argument ARG, for use
1708 in the hash tables of template specializations. */
1710 hashval_t
1712 {
1732 {
1740 {
1745 }
1767 {
1771 {
1774 }
1776 }
1780 {
1783 }
1794 val = iterative_hash_template_arg
1806 val);
1808 val);
1817 /* A lambda can't appear in a template arg, but don't crash on
1818 erroneous input. */
1830 /* Now hash operands as usual. */
1835 }
1838 {
1841 {
1842 // We want an alias specialization that survived strip_typedefs
1843 // to hash differently from its TYPE_CANONICAL, to avoid hash
1844 // collisions that compare as different in template_args_equal.
1845 // These could be dependent specializations that strip_typedefs
1846 // left alone, or untouched specializations because
1847 // coerce_template_parms returns the unconverted template
1848 // arguments if it sees incomplete argument packs.
1851 }
1854 val);
1857 /* Otherwise just compare the types during lookup. */
1866 {
1871 }
1872 }
1875 }
1877 /* Unregister the specialization SPEC as a specialization of TMPL.
1878 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1879 if the SPEC was listed as a specialization of TMPL.
1881 Note that SPEC has been ggc_freed, so we can't look inside it. */
1883 bool
1885 {
1887 spec_entry elt;
1895 {
1900 }
1903 }
1905 /* Like register_specialization, but for local declarations. We are
1906 registering SPEC, an instantiation of TMPL. */
1908 void
1910 {
1913 }
1915 /* TYPE is a class type. Returns true if TYPE is an explicitly
1916 specialized class. */
1918 bool
1920 {
1924 }
1926 /* Print the list of functions at FNS, going through all the overloads
1927 for each element of the list. Alternatively, FNS can not be a
1928 TREE_LIST, in which case it will be printed together with all the
1929 overloads.
1931 MORE and *STR should respectively be FALSE and NULL when the function
1932 is called from the outside. They are used internally on recursive
1933 calls. print_candidates manages the two parameters and leaves NULL
1934 in *STR when it ends. */
1936 static void
1938 {
1942 else
1944 {
1950 {
1953 else
1956 }
1958 }
1959 }
1961 /* Print the list of candidate FNS in an error message. FNS can also
1962 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1964 void
1966 {
1970 }
1972 /* Get a (possibly) constrained template declaration for the
1973 purpose of ordering candidates. */
1974 static tree
1976 {
1982 }
1984 /* Among candidates having the same signature, return the
1985 most constrained or NULL_TREE if there is no best candidate.
1986 If the signatures of candidates vary (e.g., template
1987 specialization vs. member function), then there can be no
1988 most constrained.
1990 Note that we don't compare constraints on the functions
1991 themselves, but rather those of their templates. */
1992 static tree
1994 {
1995 // Try to find the best candidate in a first pass.
1998 {
2005 }
2007 // Verify that the champ is better than previous candidates.
2012 }
2015 }
2018 /* Returns the template (one of the functions given by TEMPLATE_ID)
2019 which can be specialized to match the indicated DECL with the
2020 explicit template args given in TEMPLATE_ID. The DECL may be
2021 NULL_TREE if none is available. In that case, the functions in
2022 TEMPLATE_ID are non-members.
2024 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2025 specialization of a member template.
2027 The TEMPLATE_COUNT is the number of references to qualifying
2028 template classes that appeared in the name of the function. See
2029 check_explicit_specialization for a more accurate description.
2031 TSK indicates what kind of template declaration (if any) is being
2032 declared. TSK_TEMPLATE indicates that the declaration given by
2033 DECL, though a FUNCTION_DECL, has template parameters, and is
2034 therefore a template function.
2036 The template args (those explicitly specified and those deduced)
2037 are output in a newly created vector *TARGS_OUT.
2039 If it is impossible to determine the result, an error message is
2040 issued. The error_mark_node is returned to indicate failure. */
2042 static tree
2044 tree decl,
2048 tmpl_spec_kind tsk)
2049 {
2050 tree fns;
2051 tree targs;
2052 tree explicit_targs;
2055 /* A TREE_LIST of templates of which DECL may be a specialization.
2056 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2057 corresponding TREE_PURPOSE is the set of template arguments that,
2058 when used to instantiate the template, would produce a function
2059 with the signature of DECL. */
2069 /* We shouldn't be specializing a member template of an
2070 unspecialized class template; we already gave an error in
2071 check_specialization_scope, now avoid crashing. */
2075 {
2078 }
2086 /* Check for baselinks. */
2091 {
2094 }
2096 {
2099 }
2101 /* Count the number of template headers specified for this
2102 specialization. */
2112 {
2115 tf_warning_or_error,
2119 }
2121 {
2125 {
2126 tree decl_arg_types;
2127 tree fn_arg_types;
2128 tree insttype;
2130 /* In case of explicit specialization, we need to check if
2131 the number of template headers appearing in the specialization
2132 is correct. This is usually done in check_explicit_specialization,
2133 but the check done there cannot be exhaustive when specializing
2134 member functions. Consider the following code:
2136 template <> void A<int>::f(int);
2137 template <> template <> void A<int>::f(int);
2139 Assuming that A<int> is not itself an explicit specialization
2140 already, the first line specializes "f" which is a non-template
2141 member function, whilst the second line specializes "f" which
2142 is a template member function. So both lines are syntactically
2143 correct, and check_explicit_specialization does not reject
2144 them.
2146 Here, we can do better, as we are matching the specialization
2147 against the declarations. We count the number of template
2148 headers, and we check if they match TEMPLATE_COUNT + 1
2149 (TEMPLATE_COUNT is the number of qualifying template classes,
2150 plus there must be another header for the member template
2151 itself).
2153 Notice that if header_count is zero, this is not a
2154 specialization but rather a template instantiation, so there
2155 is no check we can perform here. */
2159 /* Check that the number of template arguments at the
2160 innermost level for DECL is the same as for FN. */
2168 /* DECL might be a specialization of FN. */
2172 /* For a non-static member function, we need to make sure
2173 that the const qualification is the same. Since
2174 get_bindings does not try to merge the "this" parameter,
2175 we must do the comparison explicitly. */
2177 {
2182 /* And the ref-qualification. */
2186 }
2188 /* Skip the "this" parameter and, for constructors of
2189 classes with virtual bases, the VTT parameter. A
2190 full specialization of a constructor will have a VTT
2191 parameter, but a template never will. */
2192 decl_arg_types
2194 fn_arg_types
2197 /* Function templates cannot be specializations; there are
2198 no partial specializations of functions. Therefore, if
2199 the type of DECL does not match FN, there is no
2200 match.
2202 Note that it should never be the case that we have both
2203 candidates added here, and for regular member functions
2204 below. */
2206 {
2210 }
2212 /* See whether this function might be a specialization of this
2213 template. Suppress access control because we might be trying
2214 to make this specialization a friend, and we have already done
2215 access control for the declaration of the specialization. */
2221 /* We cannot deduce template arguments that when used to
2222 specialize TMPL will produce DECL. */
2226 /* We deduced something involving 'auto', which isn't a valid
2227 template argument. */
2230 /* Remove, from the set of candidates, all those functions
2231 whose constraints are not satisfied. */
2235 // Then, try to form the new function type.
2239 fn_arg_types
2244 /* Save this template, and the arguments deduced. */
2246 }
2248 /* FN is an ordinary member function, and we need a
2249 specialization of a member template. */
2250 ;
2252 /* We can get IDENTIFIER_NODEs here in certain erroneous
2253 cases. */
2254 ;
2256 /* This is just an ordinary non-member function. Nothing can
2257 be a specialization of that. */
2258 ;
2260 /* Cannot specialize functions that are created implicitly. */
2261 ;
2262 else
2263 {
2264 tree decl_arg_types;
2266 /* This is an ordinary member function. However, since
2267 we're here, we can assume its enclosing class is a
2268 template class. For example,
2270 template <typename T> struct S { void f(); };
2271 template <> void S<int>::f() {}
2273 Here, S<int>::f is a non-template, but S<int> is a
2274 template class. If FN has the same type as DECL, we
2275 might be in business. */
2278 /* Its enclosing class is an explicit specialization
2279 of a template class. This is not a candidate. */
2284 /* The return types differ. */
2287 /* Adjust the type of DECL in case FN is a static member. */
2294 decl_arg_types))
2302 // If the deduced arguments do not satisfy the constraints,
2303 // this is not a candidate.
2307 // Add the candidate.
2309 }
2310 }
2313 {
2314 /* We have:
2316 [temp.expl.spec]
2318 It is possible for a specialization with a given function
2319 signature to be instantiated from more than one function
2320 template. In such cases, explicit specification of the
2321 template arguments must be used to uniquely identify the
2322 function template specialization being specialized.
2324 Note that here, there's no suggestion that we're supposed to
2325 determine which of the candidate templates is most
2326 specialized. However, we, also have:
2328 [temp.func.order]
2330 Partial ordering of overloaded function template
2331 declarations is used in the following contexts to select
2332 the function template to which a function template
2333 specialization refers:
2335 -- when an explicit specialization refers to a function
2336 template.
2338 So, we do use the partial ordering rules, at least for now.
2339 This extension can only serve to make invalid programs valid,
2340 so it's safe. And, there is strong anecdotal evidence that
2341 the committee intended the partial ordering rules to apply;
2342 the EDG front end has that behavior, and John Spicer claims
2343 that the committee simply forgot to delete the wording in
2344 [temp.expl.spec]. */
2347 {
2350 }
2351 }
2353 // Concepts allows multiple declarations of member functions
2354 // with the same signature. Like above, we need to rely on
2355 // on the partial ordering of those candidates to determine which
2356 // is the best.
2358 {
2360 {
2363 }
2364 }
2367 {
2374 else
2377 }
2381 {
2387 }
2389 /* We have one, and exactly one, match. */
2391 {
2395 // Propagate the candidate's constraints to the declaration.
2398 /* DECL is a re-declaration or partial instantiation of a template
2399 function. */
2402 /* It was a specialization of an ordinary member function in a
2403 template class. */
2405 }
2407 /* It was a specialization of a template. */
2410 {
2415 }
2416 else
2419 }
2421 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2422 but with the default argument values filled in from those in the
2423 TMPL_TYPES. */
2425 static tree
2427 tree tmpl_types)
2428 {
2429 tree new_spec_types;
2437 /* Substitute into the rest of the list. */
2438 new_spec_types =
2442 /* Add the default argument for this parameter. */
2445 new_spec_types);
2446 }
2448 /* DECL is an explicit specialization. Replicate default arguments
2449 from the template it specializes. (That way, code like:
2451 template <class T> void f(T = 3);
2452 template <> void f(double);
2453 void g () { f (); }
2455 works, as required.) An alternative approach would be to look up
2456 the correct default arguments at the call-site, but this approach
2457 is consistent with how implicit instantiations are handled. */
2459 static void
2461 {
2462 tree tmpl;
2463 tree spec_types;
2464 tree tmpl_types;
2465 tree new_spec_types;
2466 tree old_type;
2467 tree new_type;
2468 tree t;
2473 /* See if there's anything we need to do. */
2486 {
2487 /* Remove the this pointer, but remember the object's type for
2488 CV quals. */
2494 {
2495 /* DECL may contain more parameters than TMPL due to the extra
2496 in-charge parameter in constructors and destructors. */
2499 }
2501 {
2504 }
2505 }
2507 /* Compute the merged default arguments. */
2508 new_spec_types =
2511 /* Compute the new FUNCTION_TYPE. */
2513 {
2517 new_spec_types);
2520 /* Put the in-charge parameter back. */
2523 new_spec_types);
2527 new_spec_types);
2528 }
2529 else
2531 new_spec_types);
2537 }
2539 /* Return the number of template headers we expect to see for a definition
2540 or specialization of CTYPE or one of its non-template members. */
2542 int
2544 {
2548 {
2549 /* You're supposed to have one `template <...>' for every
2550 template class, but you don't need one for a full
2551 specialization. For example:
2553 template <class T> struct S{};
2554 template <> struct S<int> { void f(); };
2555 void S<int>::f () {}
2557 is correct; there shouldn't be a `template <>' for the
2558 definition of `S<int>::f'. */
2560 /* If CTYPE does not have template information of any
2561 kind, then it is not a template, nor is it nested
2562 within a template. */
2570 }
2573 }
2575 /* Do a simple sanity check on the template headers that precede the
2576 variable declaration DECL. */
2578 void
2580 {
2585 {
2588 "variable templates only available with "
2591 // Namespace-scope variable templates should have a template header.
2593 }
2595 {
2596 auto_diagnostic_group d;
2598 "too many template headers for %qD "
2604 "members of an explicitly specialized class are defined "
2606 }
2607 }
2609 /* An explicit specialization whose declarator-id or class-head-name is not
2610 qualified shall be declared in the nearest enclosing namespace of the
2611 template, or, if the namespace is inline (7.3.1), any namespace from its
2612 enclosing namespace set.
2614 If the name declared in the explicit instantiation is an unqualified name,
2615 the explicit instantiation shall appear in the namespace where its template
2616 is declared or, if that namespace is inline (7.3.1), any namespace from its
2617 enclosing namespace set. */
2619 void
2621 {
2626 {
2632 /* This was allowed in C++98, so only pedwarn. */
2634 "outside its namespace must use a nested-name-"
2636 }
2637 }
2639 /* Warn for a template specialization SPEC that is missing some of a set
2640 of function or type attributes that the template TEMPL is declared with.
2641 ATTRLIST is a list of additional attributes that SPEC should be taken
2642 to ultimately be declared with. */
2644 static void
2646 {
2653 /* Avoid warning if either declaration or its type is deprecated. */
2675 /* Avoid warning if the primary has no attributes. */
2679 /* Avoid warning if either declaration contains an attribute on
2680 the white list below. */
2683 };
2691 /* Avoid warning if the difference between the primary and
2692 the specialization is not in one of the attributes below. */
2696 };
2698 /* Put together a list of the black listed attributes that the primary
2699 template is declared with that the specialization is not, in case
2700 it's not apparent from the most recent declaration of the primary. */
2702 pretty_printer str;
2705 {
2707 {
2712 {
2722 }
2723 }
2724 }
2729 auto_diagnostic_group d;
2732 spec))
2738 }
2740 /* Check to see if the function just declared, as indicated in
2741 DECLARATOR, and in DECL, is a specialization of a function
2742 template. We may also discover that the declaration is an explicit
2743 instantiation at this point.
2745 Returns DECL, or an equivalent declaration that should be used
2746 instead if all goes well. Issues an error message if something is
2747 amiss. Returns error_mark_node if the error is not easily
2748 recoverable.
2750 FLAGS is a bitmask consisting of the following flags:
2752 2: The function has a definition.
2753 4: The function is a friend.
2755 The TEMPLATE_COUNT is the number of references to qualifying
2756 template classes that appeared in the name of the function. For
2757 example, in
2759 template <class T> struct S { void f(); };
2760 void S<int>::f();
2762 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2763 classes are not counted in the TEMPLATE_COUNT, so that in
2765 template <class T> struct S {};
2766 template <> struct S<int> { void f(); }
2767 template <> void S<int>::f();
2769 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2770 invalid; there should be no template <>.)
2772 If the function is a specialization, it is marked as such via
2773 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2774 is set up correctly, and it is added to the list of specializations
2775 for that template. */
2777 tree
2779 tree decl,
2782 tree attrlist)
2783 {
2792 tmpl_spec_kind tsk;
2795 {
2798 else
2800 }
2801 else
2805 {
2808 {
2811 }
2813 {
2815 /* This could be something like:
2817 template <class T> void f(T);
2818 class S { friend void f<>(int); } */
2820 else
2821 {
2822 /* This case handles bogus declarations like template <>
2823 template <class T> void f<int>(); */
2826 declarator);
2828 }
2829 }
2833 /* The error has already been reported in
2834 check_specialization_scope. */
2840 /* Fall through. */
2853 decl);
2856 else
2860 /* Fall through. */
2866 /* In cases like template<> constexpr bool v = true;
2867 We'll give an error in check_template_variable. */
2873 else
2879 {
2880 /* This case handles bogus declarations like template <>
2881 template <class T> void f<int>(); */
2885 declarator);
2887 {
2888 /* Partial specialization of variable template. */
2892 }
2896 else
2900 ok:;
2901 }
2904 /* This is a specialization of a member template, without
2905 specialization the containing class. Something like:
2907 template <class T> struct S {
2908 template <class U> void f (U);
2909 };
2910 template <> template <class U> void S<int>::f(U) {}
2912 That's a specialization -- but of the entire template. */
2918 }
2921 /* This doesn't apply to variable templates. */
2924 {
2928 {
2932 }
2933 }
2936 {
2941 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2943 {
2944 tree fns;
2949 else
2950 {
2951 /* If there is no class context, the explicit instantiation
2952 must be at namespace scope. */
2955 /* Find the namespace binding, using the declaration
2956 context. */
2960 /* If lookup fails, look for a friend declaration so we can
2961 give a better diagnostic. */
2967 {
2970 }
2971 }
2974 }
2980 {
2982 /* A specialization in class scope. This is invalid,
2983 but the error will already have been flagged by
2984 check_specialization_scope. */
2986 else
2987 {
2988 /* It's not valid to write an explicit instantiation in
2989 class scope, e.g.:
2991 class C { template void f(); }
2993 This case is caught by the parser. However, on
2994 something like:
2996 template class C { void f(); };
2998 (which is invalid) we can get here. The error will be
2999 issued later. */
3000 ;
3001 }
3004 }
3007 {
3008 // We'll match variable templates in start_decl.
3012 /* Find the list of functions in ctype that have the same
3013 name as the declared function. */
3017 {
3021 {
3022 /* From [temp.expl.spec]:
3024 If such an explicit specialization for the member
3025 of a class template names an implicitly-declared
3026 special member function (clause _special_), the
3027 program is ill-formed.
3029 Similar language is found in [temp.explicit]. */
3032 }
3035 }
3037 /* For a type-conversion operator, We might be looking for
3038 `operator int' which will be a specialization of
3039 `operator T'. Grab all the conversion operators, and
3040 then select from them. */
3045 {
3048 }
3049 else
3051 }
3053 /* Figure out what exactly is being specialized at this point.
3054 Note that for an explicit instantiation, even one for a
3055 member function, we cannot tell a priori whether the
3056 instantiation is for a member template, or just a member
3057 function of a template class. Even if a member template is
3058 being instantiated, the member template arguments may be
3059 elided if they can be deduced from the rest of the
3060 declaration. */
3063 member_specialization,
3064 template_count,
3065 tsk);
3068 /* We couldn't figure out what this declaration was
3069 specializing. */
3071 else
3072 {
3075 {
3076 auto_diagnostic_group d;
3078 "friend declaration %qD is not visible to "
3082 }
3090 {
3091 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3092 is done by do_decl_instantiation later. */
3098 {
3099 /* If TMPL is not the most general template (for
3100 example, if TMPL is a friend template that is
3101 injected into namespace scope), then there will
3102 be too many levels of TARGS. Remove some of them
3103 here. */
3105 tree new_targs;
3112 }
3115 }
3117 /* If we thought that the DECL was a member function, but it
3118 turns out to be specializing a static member function,
3119 make DECL a static member function as well. */
3125 /* If this is a specialization of a member template of a
3126 template class, we want to return the TEMPLATE_DECL, not
3127 the specialization of it. */
3129 {
3134 {
3135 tree parm;
3139 /* We want to use the argument list specified in the
3140 definition, not in the original declaration. */
3145 }
3148 }
3150 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3156 /* Inherit default function arguments from the template
3157 DECL is specializing. */
3161 /* This specialization has the same protection as the
3162 template it specializes. */
3166 /* 7.1.1-1 [dcl.stc]
3168 A storage-class-specifier shall not be specified in an
3169 explicit specialization...
3171 The parser rejects these, so unless action is taken here,
3172 explicit function specializations will always appear with
3173 global linkage.
3175 The action recommended by the C++ CWG in response to C++
3176 defect report 605 is to make the storage class and linkage
3177 of the explicit specialization match the templated function:
3179 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3180 */
3182 {
3186 /* A concept cannot be specialized. */
3188 {
3190 gen_tmpl);
3192 }
3194 /* This specialization has the same linkage and visibility as
3195 the function template it specializes. */
3198 {
3201 }
3204 {
3207 }
3208 }
3210 /* If DECL is a friend declaration, declared using an
3211 unqualified name, the namespace associated with DECL may
3212 have been set incorrectly. For example, in:
3214 template <typename T> void f(T);
3215 namespace N {
3216 struct S { friend void f<int>(int); }
3217 }
3219 we will have set the DECL_CONTEXT for the friend
3220 declaration to N, rather than to the global namespace. */
3225 /* This is not really a declaration of a specialization.
3226 It's just the name of an instantiation. But, it's not
3227 a request for an instantiation, either. */
3230 /* A specialization is not necessarily COMDAT. */
3236 /* If this is a full specialization, register it so that we can find
3237 it again. Partial specializations will be registered in
3238 process_partial_specialization. */
3240 {
3245 }
3248 /* A 'structor should already have clones. */
3254 }
3255 }
3258 }
3260 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3261 parameters. These are represented in the same format used for
3262 DECL_TEMPLATE_PARMS. */
3264 int
3266 {
3267 const_tree p1;
3268 const_tree p2;
3276 {
3288 {
3292 /* If either of the template parameters are invalid, assume
3293 they match for the sake of error recovery. */
3306 }
3307 }
3310 /* One set of parameters has more parameters lists than the
3311 other. */
3315 }
3317 /* Determine whether PARM is a parameter pack. */
3319 bool
3321 {
3322 /* Determine if we have a non-type template parameter pack. */
3329 /* If this is a list of template parameters, we could get a
3330 TYPE_DECL or a TEMPLATE_DECL. */
3334 /* Otherwise it must be a type template parameter. */
3338 }
3340 /* Determine if T is a function parameter pack. */
3342 bool
3344 {
3348 }
3350 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3351 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3353 tree
3355 {
3362 }
3364 /* Return true iff the function parameter PARAM_DECL was expanded
3365 from the function parameter pack PACK. */
3367 bool
3369 {
3374 /* The parameter pack and its pack arguments have the same
3375 DECL_PARM_INDEX. */
3377 }
3379 /* Determine whether ARGS describes a variadic template args list,
3380 i.e., one that is terminated by a template argument pack. */
3382 static bool
3384 {
3386 tree last_parm;
3400 }
3402 /* Generate a new name for the parameter pack name NAME (an
3403 IDENTIFIER_NODE) that incorporates its */
3405 static tree
3407 {
3408 /* Munge the name to include the parameter index. */
3409 #define NUMBUF_LEN 128
3423 }
3425 /* Return true if T is a primary function, class or alias template
3426 specialization, not including the template pattern. */
3428 bool
3430 {
3446 }
3448 /* Return true if PARM is a template template parameter. */
3450 bool
3452 {
3454 }
3456 /* Return true iff PARM is a DECL representing a type template
3457 parameter. */
3459 bool
3461 {
3466 }
3468 /* Return the template parameters of T if T is a
3469 primary template instantiation, NULL otherwise. */
3471 tree
3473 {
3478 parms = INNERMOST_TEMPLATE_PARMS
3482 }
3484 /* Return the template parameters of the LEVELth level from the full list
3485 of template parameters PARMS. */
3487 tree
3489 {
3490 tree p;
3501 }
3503 /* Returns the template arguments of T if T is a template instantiation,
3504 NULL otherwise. */
3506 tree
3508 {
3516 }
3518 /* Return the argument pack elements of T if T is a template argument pack,
3519 NULL otherwise. */
3521 tree
3523 {
3529 }
3531 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3532 ARGUMENT_PACK_SELECT represents. */
3534 static tree
3536 {
3540 /* If the selected argument is an expansion E, that most likely means we were
3541 called from gen_elem_of_pack_expansion_instantiation during the
3542 substituting of an argument pack (of which the Ith element is a pack
3543 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3544 In this case, the Ith element resulting from this substituting is going to
3545 be a pack expansion, which pattern is the pattern of E. Let's return the
3546 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3547 resulting pack expansion from it. */
3549 {
3550 /* Make sure we aren't throwing away arg info. */
3553 }
3556 }
3559 /* True iff FN is a function representing a built-in variadic parameter
3560 pack. */
3562 bool
3564 {
3574 }
3576 /* True iff CALL is a call to a function representing a built-in variadic
3577 parameter pack. */
3579 static bool
3581 {
3585 }
3587 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3589 static tree
3591 tree in_decl)
3592 {
3598 {
3600 {
3603 }
3608 }
3609 else
3610 {
3614 /* Calculate the largest value of len that won't make the size of the vec
3615 overflow an int. The compiler will exceed resource limits long before
3616 this, but it seems a decent place to diagnose. */
3620 {
3625 }
3633 }
3634 }
3636 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3637 CALL. */
3639 static tree
3641 tree in_decl)
3642 {
3652 }
3654 /* Structure used to track the progress of find_parameter_packs_r. */
3655 struct find_parameter_pack_data
3656 {
3657 /* TREE_LIST that will contain all of the parameter packs found by
3658 the traversal. */
3661 /* Set of AST nodes that have been visited by the traversal. */
3664 /* True iff we're making a type pack expansion. */
3666 };
3668 /* Identifies all of the argument packs that occur in a template
3669 argument and appends them to the TREE_LIST inside DATA, which is a
3670 find_parameter_pack_data structure. This is a subroutine of
3671 make_pack_expansion and uses_parameter_packs. */
3672 static tree
3674 {
3680 /* Handle type aliases/typedefs. */
3682 {
3689 }
3691 /* Identify whether this is a parameter pack or not. */
3693 {
3701 /* FALLTHRU */
3703 /* If the placeholder appears in the decl-specifier-seq of a function
3704 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3705 is a pack expansion, the invented template parameter is a template
3706 parameter pack. */
3716 {
3717 /* We don't want to walk into the type of a PARM_DECL,
3718 because we don't want to see the type parameter pack. */
3721 }
3726 {
3727 /* We don't want to walk into the type of a variadic capture proxy,
3728 because we don't want to see the type parameter pack. */
3731 }
3733 {
3735 find_parameter_packs_r,
3738 }
3750 /* Not a parameter pack. */
3752 }
3755 {
3756 /* Add this parameter pack to the list. */
3758 }
3764 /* This switch statement will return immediately if we don't find a
3765 parameter pack. */
3767 {
3772 /* Check the template itself. */
3775 /* Check the template arguments. */
3789 /* Ignore the declaration of a capture proxy for a parameter pack. */
3797 /* Fall through. */
3842 {
3843 /* Look at explicit captures. */
3848 /* Since we defer implicit capture, look in the parms and body. */
3856 }
3859 {
3860 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3861 type_pack_expansion_p to false so that any placeholders
3862 within the expression don't get marked as parameter packs. */
3870 }
3879 /* Don't walk into IF_STMT_EXTRA_ARGS. */
3885 }
3888 }
3890 /* Determines if the expression or type T uses any parameter packs. */
3891 bool
3893 {
3902 }
3904 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3905 representation a base-class initializer into a parameter pack
3906 expansion. If all goes well, the resulting node will be an
3907 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3908 respectively. */
3909 tree
3911 {
3912 tree result;
3921 {
3922 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3923 class initializer. In this case, the TREE_PURPOSE will be a
3924 _TYPE node (representing the base class expansion we're
3925 initializing) and the TREE_VALUE will be a TREE_LIST
3926 containing the initialization arguments.
3928 The resulting expansion looks somewhat different from most
3929 expansions. Rather than returning just one _EXPANSION, we
3930 return a TREE_LIST whose TREE_PURPOSE is a
3931 TYPE_PACK_EXPANSION containing the bases that will be
3932 initialized. The TREE_VALUE will be identical to the
3933 original TREE_VALUE, which is a list of arguments that will
3934 be passed to each base. We do not introduce any new pack
3935 expansion nodes into the TREE_VALUE (although it is possible
3936 that some already exist), because the TREE_PURPOSE and
3937 TREE_VALUE all need to be expanded together with the same
3938 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3939 resulting TREE_PURPOSE will mention the parameter packs in
3940 both the bases and the arguments to the bases. */
3941 tree purpose;
3942 tree value;
3945 /* Determine which parameter packs will be used by the base
3946 class expansion. */
3955 {
3958 arg);
3961 }
3964 {
3965 /* Collect the sets of parameter packs used in each of the
3966 initialization arguments. */
3968 {
3969 /* Determine which parameter packs will be expanded in this
3970 argument. */
3973 }
3974 }
3978 /* Create the pack expansion type for the base type. */
3984 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3985 they will rarely be compared to anything. */
3989 }
3994 /* Build the PACK_EXPANSION_* node. */
3995 result = for_types
4000 {
4001 /* Propagate type and const-expression information. */
4004 /* Mark this read now, since the expansion might be length 0. */
4006 }
4007 else
4008 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4009 they will rarely be compared to anything. */
4012 /* Determine which parameter packs will be expanded. */
4019 /* Make sure we found some parameter packs. */
4021 {
4023 {
4026 else
4028 }
4030 }
4036 }
4038 /* Checks T for any "bare" parameter packs, which have not yet been
4039 expanded, and issues an error if any are found. This operation can
4040 only be done on full expressions or types (e.g., an expression
4041 statement, "if" condition, etc.), because we could have expressions like:
4043 foo(f(g(h(args)))...)
4045 where "args" is a parameter pack. check_for_bare_parameter_packs
4046 should not be called for the subexpressions args, h(args),
4047 g(h(args)), or f(g(h(args))), because we would produce erroneous
4048 error messages.
4050 Returns TRUE and emits an error if there were bare parameter packs,
4051 returns FALSE otherwise. */
4052 bool
4054 {
4061 /* A lambda might use a parameter pack from the containing context. */
4076 {
4081 {
4092 else
4097 else
4101 }
4104 }
4107 }
4109 /* Expand any parameter packs that occur in the template arguments in
4110 ARGS. */
4111 tree
4113 {
4122 /* First, determine if we need to expand anything, and the number of
4123 slots we'll need. */
4125 {
4130 {
4134 else
4136 }
4137 else
4138 {
4140 num_result_args++;
4141 }
4142 }
4144 /* If no expansion is necessary, we're done. */
4148 /* Expand arguments. */
4151 non_default_args_count =
4154 {
4157 {
4164 }
4165 else
4166 {
4169 }
4170 }
4174 }
4176 /* Checks if DECL shadows a template parameter.
4178 [temp.local]: A template-parameter shall not be redeclared within its
4179 scope (including nested scopes).
4181 Emits an error and returns TRUE if the DECL shadows a parameter,
4182 returns FALSE otherwise. */
4184 bool
4186 {
4187 tree olddecl;
4189 /* If we're not in a template, we can't possibly shadow a template
4190 parameter. */
4194 /* Figure out what we're shadowing. */
4198 /* If there's no previous binding for this name, we're not shadowing
4199 anything, let alone a template parameter. */
4203 /* If we're not shadowing a template parameter, we're done. Note
4204 that OLDDECL might be an OVERLOAD (or perhaps even an
4205 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4206 node. */
4210 /* We check for decl != olddecl to avoid bogus errors for using a
4211 name inside a class. We check TPFI to avoid duplicate errors for
4212 inline member templates. */
4218 /* Don't complain about the injected class name, as we've already
4219 complained about the class itself. */
4226 else
4231 }
4233 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4234 ORIG_LEVEL, DECL, and TYPE. */
4236 static tree
4240 tree decl,
4241 tree type)
4242 {
4253 }
4255 /* Find the canonical type parameter for the given template type
4256 parameter. Returns the canonical type parameter, which may be TYPE
4257 if no such parameter existed. */
4259 static tree
4261 {
4262 tree list;
4276 else
4277 {
4281 }
4282 }
4284 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4285 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4286 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4287 new one is created. */
4289 static tree
4291 tsubst_flags_t complain)
4292 {
4297 {
4316 /* Template template parameters need this. */
4318 {
4325 }
4326 }
4329 }
4331 /* Process information from new template parameter PARM and append it
4332 to the LIST being built. This new parameter is a non-type
4333 parameter iff IS_NON_TYPE is true. This new parameter is a
4334 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4335 is in PARM_LOC. */
4337 tree
4340 {
4349 {
4353 {
4357 else
4359 }
4362 }
4365 {
4371 {
4372 /* [temp.param]
4374 The top-level cv-qualifiers on the template-parameter are
4375 ignored when determining its type. */
4380 && !is_parameter_pack
4381 /* If we're in a nested template parameter list, the template
4382 template parameter could be a parameter pack. */
4384 {
4385 /* This template parameter is not a parameter pack, but it
4386 should be. Complain about "bare" parameter packs. */
4389 /* Recover by calling this a parameter pack. */
4391 }
4392 }
4394 /* A template parameter is not modifiable. */
4403 processing_template_decl,
4408 }
4409 else
4410 {
4411 tree t;
4415 {
4417 /* This is for distinguishing between real templates and template
4418 template parameters */
4422 }
4423 else
4424 {
4426 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4429 }
4436 processing_template_decl,
4440 }
4444 /* Build requirements for the type/template parameter.
4445 This must be done after SET_DECL_TEMPLATE_PARM_P or
4446 process_template_parm could fail. */
4451 /* Build the parameter node linking the parameter declaration,
4452 its default argument (if any), and its constraints (if any). */
4457 }
4459 /* The end of a template parameter list has been reached. Process the
4460 tree list into a parameter vector, converting each parameter into a more
4461 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4462 as PARM_DECLs. */
4464 tree
4466 {
4471 /* Pop the dummy parameter level and add the real one. */
4474 current_template_parms
4479 {
4483 }
4488 }
4490 // Explicitly indicate the end of the template parameter list. We assume
4491 // that the current template parameters have been constructed and/or
4492 // managed explicitly, as when creating new template template parameters
4493 // from a shorthand constraint.
4494 void
4496 {
4498 }
4500 /* end_template_decl is called after a template declaration is seen. */
4502 void
4504 {
4510 /* This matches the pushlevel in begin_template_parm_list. */
4515 }
4517 /* Takes a TREE_LIST representing a template parameter and convert it
4518 into an argument suitable to be passed to the type substitution
4519 functions. Note that If the TREE_LIST contains an error_mark
4520 node, the returned argument is error_mark_node. */
4522 tree
4524 {
4537 {
4541 {
4542 /* Turn this argument into a TYPE_ARGUMENT_PACK
4543 with a single element, which expands T. */
4552 }
4553 }
4554 else
4555 {
4559 {
4560 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4561 with a single element, which expands T. */
4571 }
4572 else
4574 }
4576 }
4578 /* Given a single level of template parameters (a TREE_VEC), return it
4579 as a set of template arguments. */
4581 static tree
4583 {
4593 }
4595 /* Given a set of template parameters, return them as a set of template
4596 arguments. The template parameters are represented as a TREE_VEC, in
4597 the form documented in cp-tree.h for template arguments. */
4599 static tree
4601 {
4602 tree header;
4607 /* If there is only one level of template parameters, we do not
4608 create a TREE_VEC of TREE_VECs. Instead, we return a single
4609 TREE_VEC containing the arguments. */
4614 {
4619 else
4621 }
4624 }
4626 /* Within the declaration of a template, return the currently active
4627 template parameters as an argument TREE_VEC. */
4629 static tree
4631 {
4633 }
4635 /* Update the declared TYPE by doing any lookups which were thought to be
4636 dependent, but are not now that we know the SCOPE of the declarator. */
4638 tree
4640 {
4651 /* Don't bother building up the args in this case. */
4653 {
4654 /* tsubst in the args corresponding to the template parameters,
4655 including auto if present. Most things will be unchanged, but
4656 make_typename_type and tsubst_qualified_id will resolve
4657 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4660 tree pushed;
4662 {
4666 }
4671 }
4677 {
4680 else
4682 }
4684 }
4686 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4687 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4688 the new template is a member template. */
4690 static tree
4692 {
4701 }
4703 struct template_parm_data
4704 {
4705 /* The level of the template parameters we are currently
4706 processing. */
4709 /* The index of the specialization argument we are currently
4710 processing. */
4713 /* An array whose size is the number of template parameters. The
4714 elements are nonzero if the parameter has been used in any one
4715 of the arguments processed so far. */
4718 /* An array whose size is the number of template arguments. The
4719 elements are nonzero if the argument makes use of template
4720 parameters of this level. */
4722 };
4724 /* Subroutine of push_template_decl used to see if each template
4725 parameter in a partial specialization is used in the explicit
4726 argument list. If T is of the LEVEL given in DATA (which is
4727 treated as a template_parm_data*), then DATA->PARMS is marked
4728 appropriately. */
4730 static int
4732 {
4740 {
4743 }
4745 /* In C++17 the type of a non-type argument is a deduced context. */
4750 data,
4751 NULL,
4754 /* Return zero so that for_each_template_parm will continue the
4755 traversal of the tree; we want to mark *every* template parm. */
4757 }
4759 /* Process the partial specialization DECL. */
4761 static tree
4763 {
4770 tree inner_parms;
4771 tree inst;
4781 /* A concept cannot be specialized. */
4783 {
4786 }
4791 /* We check that each of the template parameters given in the
4792 partial specialization is used in the argument list to the
4793 specialization. For example:
4795 template <class T> struct S;
4796 template <class T> struct S<T*>;
4798 The second declaration is OK because `T*' uses the template
4799 parameter T, whereas
4801 template <class T> struct S<int>;
4803 is no good. Even trickier is:
4805 template <class T>
4806 struct S1
4807 {
4808 template <class U>
4809 struct S2;
4810 template <class U>
4811 struct S2<T>;
4812 };
4814 The S2<T> declaration is actually invalid; it is a
4815 full-specialization. Of course,
4817 template <class U>
4818 struct S2<T (*)(U)>;
4820 or some such would have been OK. */
4828 {
4833 NULL,
4835 }
4838 {
4839 /* One of the template parms was not used in a deduced context in the
4840 specialization. */
4842 {
4846 }
4850 }
4855 /* [temp.class.spec]
4857 The argument list of the specialization shall not be identical to
4858 the implicit argument list of the primary template. */
4859 tree main_args
4862 && (!flag_concepts
4865 {
4868 "any template arguments; to define the primary template, "
4870 else
4872 "template arguments and is not more constrained than "
4873 "the primary template; to define the primary template, "
4876 }
4878 /* A partial specialization that replaces multiple parameters of the
4879 primary template with a pack expansion is less specialized for those
4880 parameters. */
4882 {
4884 "primary template because it replaces multiple parameters "
4887 /* Avoid crash in process_partial_specialization. */
4889 }
4891 /* If we aren't in a dependent class, we can actually try deduction. */
4893 /* FIXME we should be able to handle a partial specialization of a
4894 partial instantiation, but currently we can't (c++/41727). */
4897 {
4898 auto_diagnostic_group d;
4902 maintmpl);
4903 }
4905 /* [temp.class.spec]
4907 A partially specialized non-type argument expression shall not
4908 involve template parameters of the partial specialization except
4909 when the argument expression is a simple identifier.
4911 The type of a template parameter corresponding to a specialized
4912 non-type argument shall not be dependent on a parameter of the
4913 specialization.
4915 Also, we verify that pack expansions only occur at the
4916 end of the argument list. */
4920 {
4927 {
4928 /* Extract the arguments from the argument pack. We'll be
4929 iterating over these in the following loop. */
4932 }
4935 {
4937 /* Get the Jth argument in the parameter pack. */
4941 {
4942 /* Pack expansions must come at the end of the
4943 argument list. */
4946 {
4950 else
4953 }
4954 }
4957 /* We only care about the pattern. */
4963 /* This next two lines are the `argument expression is not just a
4964 simple identifier' condition and also the `specialized
4965 non-type argument' bit. */
4969 {
4973 arg);
4974 else
4975 {
4976 /* Look at the corresponding template parameter,
4977 marking which template parameters its type depends
4978 upon. */
4982 {
4983 /* We haven't yet initialized TPD2. Do so now. */
4985 /* The number of parameters here is the number in the
4986 main template, which, as checked in the assertion
4987 above, is NARGS. */
4991 }
4993 /* Mark the template parameters. But this time, we're
4994 looking for the template parameters of the main
4995 template, not in the specialization. */
5002 NULL,
5006 {
5007 /* The type depended on some template parameters.
5008 If they are fully specialized in the
5009 specialization, that's OK. */
5018 "type %qT of template argument %qE depends "
5020 "type %qT of template argument %qE depends "
5022 type,
5023 arg);
5024 }
5025 }
5026 }
5027 }
5028 }
5030 /* We should only get here once. */
5034 // Build the template decl.
5043 /* Give template template parms a DECL_CONTEXT of the template
5044 for which they are a parameter. */
5046 {
5050 }
5053 /* We didn't register this in check_explicit_specialization so we could
5054 wait until the constraints were set. */
5056 else
5066 {
5072 {
5080 "declaration of %qD ambiguates earlier template "
5084 "partial specialization of %qD after instantiation "
5086 }
5087 }
5090 }
5092 /* PARM is a template parameter of some form; return the corresponding
5093 TEMPLATE_PARM_INDEX. */
5095 static tree
5097 {
5110 }
5112 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5113 parameter packs used by the template parameter PARM. */
5115 static void
5117 {
5118 /* A type parm can't refer to another parm. */
5122 {
5126 }
5133 }
5135 /* PARM is a template parameter pack. Return any parameter packs used in
5136 its type or the type of any of its template parameters. If there are
5137 any such packs, it will be instantiated into a fixed template parameter
5138 list by partial instantiation rather than be fully deduced. */
5140 tree
5142 {
5143 /* This can only be true in a member template. */
5146 /* This can only be true for a parameter pack. */
5149 /* A type parm can't refer to another parm. */
5163 }
5165 /* Check that a template declaration's use of default arguments and
5166 parameter packs is not invalid. Here, PARMS are the template
5167 parameters. IS_PRIMARY is true if DECL is the thing declared by
5168 a primary template. IS_PARTIAL is true if DECL is a partial
5169 specialization.
5171 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5172 function template declaration or a friend class template
5173 declaration. In the function case, 1 indicates a declaration, 2
5174 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5175 emitted for extraneous default arguments.
5177 Returns TRUE if there were no errors found, FALSE otherwise. */
5179 bool
5182 {
5185 tree parm_level;
5188 /* [temp.param]
5190 A default template-argument shall not be specified in a
5191 function template declaration or a function template definition, nor
5192 in the template-parameter-list of the definition of a member of a
5193 class template. */
5197 /* You can't have a function template declaration in a local
5198 scope, nor you can you define a member of a class template in a
5199 local scope. */
5207 /* A lambda doesn't have an explicit declaration; don't complain
5208 about the parms of the enclosing class. */
5215 /* If this is either a friend defined in the scope of the class
5216 or a member function. */
5222 /* And, if it was a member function, it really was defined in
5223 the scope of the class. */
5226 /* We already checked these parameters when the template was
5227 declared, so there's no need to do it again now. This function
5228 was defined in class scope, but we're processing its body now
5229 that the class is complete. */
5232 /* Core issue 226 (C++0x only): the following only applies to class
5233 templates. */
5236 {
5237 /* [temp.param]
5239 If a template-parameter has a default template-argument, all
5240 subsequent template-parameters shall have a default
5241 template-argument supplied. */
5243 {
5250 {
5260 {
5262 /* For better subsequent error-recovery, we indicate that
5263 there should have been a default argument. */
5266 }
5268 && !is_friend_decl
5269 /* Don't complain about an enclosing partial
5270 specialization. */
5275 /* A fixed parameter pack will be partially
5276 instantiated into a fixed length list. */
5278 {
5279 /* A primary class template can only have one
5280 parameter pack, at the end of the template
5281 parameter list. */
5289 }
5290 }
5291 }
5292 }
5295 || is_partial
5296 || !is_primary
5298 /* For an ordinary class template, default template arguments are
5299 allowed at the innermost level, e.g.:
5300 template <class T = int>
5301 struct S {};
5302 but, in a partial specialization, they're not allowed even
5303 there, as we have in [temp.class.spec]:
5305 The template parameter list of a specialization shall not
5306 contain default template argument values.
5308 So, for a partial specialization, or for a function template
5309 (in C++98/C++03), we look at all of them. */
5310 ;
5311 else
5312 /* But, for a primary class template that is not a partial
5313 specialization we look at all template parameters except the
5314 innermost ones. */
5317 /* Figure out what error message to issue. */
5332 else
5333 /* Per [temp.param]/9, "A default template-argument shall not be
5334 specified in the template-parameter-lists of the definition of
5335 a member of a class template that appears outside of the member's
5336 class.", thus if we aren't handling a member of a class template
5337 there is no need to examine the parameters. */
5341 /* If we're inside a class definition, there's no need to
5342 examine the parameters to the class itself. On the one
5343 hand, they will be checked when the class is defined, and,
5344 on the other, default arguments are valid in things like:
5345 template <class T = double>
5346 struct S { template <class U> void f(U); };
5347 Here the default argument for `S' has no bearing on the
5348 declaration of `f'. */
5350 else
5351 /* Check everything. */
5357 {
5364 {
5369 {
5371 {
5378 }
5380 /* Clear out the default argument so that we are not
5381 confused later. */
5383 }
5384 }
5386 /* At this point, if we're still interested in issuing messages,
5387 they must apply to classes surrounding the object declared. */
5391 }
5394 }
5396 /* Worker for push_template_decl_real, called via
5397 for_each_template_parm. DATA is really an int, indicating the
5398 level of the parameters we are interested in. If T is a template
5399 parameter of that level, return nonzero. */
5401 static int
5403 {
5409 else
5412 }
5414 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5415 DATA is really an int, indicating the innermost outer level of parameters.
5416 If T is a template parameter of that level or further out, return
5417 nonzero. */
5419 static int
5421 {
5427 else
5430 }
5432 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5433 parameters given by current_template_args, or reuses a
5434 previously existing one, if appropriate. Returns the DECL, or an
5435 equivalent one, if it is replaced via a call to duplicate_decls.
5437 If IS_FRIEND is true, DECL is a friend declaration. */
5439 tree
5441 {
5442 tree tmpl;
5443 tree args;
5444 tree info;
5445 tree ctx;
5449 /* True if the template is a member template, in the sense of
5450 [temp.mem]. */
5456 /* See if this is a partial specialization. */
5469 /* For a friend, we want the context of the friend, not
5470 the type of which it is a friend. */
5474 /* In the case of a virtual function, we want the class in which
5475 it is defined. */
5477 else
5478 /* Otherwise, if we're currently defining some class, the DECL
5479 is assumed to be a member of the class. */
5488 /* See if this is a primary template. */
5491 /* A friend template that specifies a class context, i.e.
5492 template <typename T> friend void A<T>::f();
5493 is not primary. */
5498 else
5502 {
5509 {
5512 }
5514 {
5516 {
5519 }
5521 {
5522 /* [temp.mem]
5524 A destructor shall not be a member template. */
5527 }
5534 {
5535 /* [basic.stc.dynamic.allocation]
5537 An allocation function can be a function
5538 template. ... Template allocation functions shall
5539 have two or more parameters. */
5542 }
5543 }
5546 {
5547 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5550 {
5556 }
5557 }
5560 /* alias-declaration */
5564 else
5565 {
5568 }
5569 }
5571 /* Check to see that the rules regarding the use of default
5572 arguments are not being violated. We check args for a friend
5573 functions when we know whether it's a definition, introducing
5574 declaration or re-declaration. */
5579 /* Ensure that there are no parameter packs in the type of this
5580 declaration that have not been expanded. */
5582 {
5583 /* Check each of the arguments individually to see if there are
5584 any bare parameter packs. */
5590 {
5593 {
5594 /* This is a PARM_DECL that contains unexpanded parameter
5595 packs. We have already complained about this in the
5596 check_for_bare_parameter_packs call, so just replace
5597 these types with ERROR_MARK_NODE. */
5600 }
5604 }
5606 /* Check for bare parameter packs in the return type and the
5607 exception specifiers. */
5609 /* Errors were already issued, set return type to int
5610 as the frontend doesn't expect error_mark_node as
5611 the return type. */
5615 }
5620 {
5623 }
5636 {
5641 /* If DECL is a TYPE_DECL for a class-template, then there won't
5642 be DECL_LANG_SPECIFIC. The information equivalent to
5643 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5647 {
5648 /* Since a template declaration already existed for this
5649 class-type, we must be redeclaring it here. Make sure
5650 that the redeclaration is valid. */
5652 current_template_parms,
5654 /* We don't need to create a new TEMPLATE_DECL; just use the
5655 one we already had. */
5657 }
5658 else
5659 {
5661 member_template_p);
5666 {
5667 /* A specialization of a member template of a template
5668 class. */
5672 }
5673 }
5674 }
5675 else
5676 {
5682 {
5685 }
5693 {
5694 tree new_tmpl;
5696 /* The declaration is a specialization of a member
5697 template, declared outside the class. Therefore, the
5698 innermost template arguments will be NULL, so we
5699 replace them with the arguments determined by the
5700 earlier call to check_explicit_specialization. */
5703 new_tmpl
5705 member_template_p);
5715 args,
5718 }
5720 /* Make sure the template headers we got make sense. */
5725 {
5730 }
5731 else
5733 {
5738 {
5742 else
5746 /* Avoid crash in import_export_decl. */
5749 }
5754 /* Can happen in erroneous input. */
5756 else
5758 }
5760 /* Check that the parms are used in the appropriate qualifying scopes
5761 in the declarator. */
5765 {
5771 /* Avoid crash in import_export_decl. */
5774 }
5775 }
5780 /* Push template declarations for global functions and types. Note
5781 that we do not try to push a global template friend declared in a
5782 template class; such a thing may well depend on the template
5783 parameters of the class. */
5786 {
5791 /* Hide template friend classes that haven't been declared yet. */
5793 {
5796 }
5797 }
5800 {
5805 /* Give template template parms a DECL_CONTEXT of the template
5806 for which they are a parameter. */
5809 {
5813 }
5819 }
5821 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5822 back to its most general template. If TMPL is a specialization,
5823 ARGS may only have the innermost set of arguments. Add the missing
5824 argument levels if necessary. */
5832 else
5833 {
5838 }
5841 && !is_friend
5844 /* Set DECL_COMDAT on template instantiations; if we force
5845 them to be emitted by explicit instantiation or -frepo,
5846 mark_needed will tell cgraph to do the right thing. */
5850 }
5852 tree
5854 {
5856 }
5858 /* FN is an inheriting constructor that inherits from the constructor
5859 template INHERITED; turn FN into a constructor template with a matching
5860 template header. */
5862 tree
5864 {
5865 tree inner_parms
5868 tree parms
5879 }
5881 /* Called when a class template TYPE is redeclared with the indicated
5882 template PARMS, e.g.:
5884 template <class T> struct S;
5885 template <class T> struct S {}; */
5887 bool
5889 {
5890 tree tmpl;
5891 tree tmpl_parms;
5895 {
5898 }
5902 /* The type is nested in some template class. Nothing to worry
5903 about here; there are no new template parameters for the nested
5904 type. */
5908 {
5910 tmpl);
5912 }
5918 {
5928 }
5931 {
5932 tree tmpl_parm;
5933 tree parm;
5934 tree tmpl_default;
5935 tree parm_default;
5949 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5950 TEMPLATE_DECL. */
5960 {
5964 }
5967 {
5968 /* We have in [temp.param]:
5970 A template-parameter may not be given default arguments
5971 by two different declarations in the same scope. */
5976 }
5979 /* Update the previous template parameters (which are the ones
5980 that will really count) with the new default value. */
5983 /* Update the new parameters, too; they'll be used as the
5984 parameters for any members. */
5987 /* Give each template template parm in this redeclaration a
5988 DECL_CONTEXT of the template for which they are a parameter. */
5990 {
5993 }
5997 }
5999 // Cannot redeclare a class template with a different set of constraints.
6001 {
6006 }
6009 }
6011 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6012 to be used when the caller has already checked
6013 (processing_template_decl
6014 && !instantiation_dependent_expression_p (expr)
6015 && potential_constant_expression (expr))
6016 and cleared processing_template_decl. */
6018 tree
6020 {
6023 complain,
6027 }
6029 /* Simplify EXPR if it is a non-dependent expression. Returns the
6030 (possibly simplified) expression. */
6032 tree
6034 {
6038 /* If we're in a template, but EXPR isn't value dependent, simplify
6039 it. We're supposed to treat:
6041 template <typename T> void f(T[1 + 1]);
6042 template <typename T> void f(T[2]);
6044 as two declarations of the same function, for example. */
6047 {
6048 processing_template_decl_sentinel s;
6050 }
6052 }
6054 tree
6056 {
6058 }
6060 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6061 an uninstantiated expression. */
6063 tree
6065 {
6069 {
6072 else
6073 {
6074 processing_template_decl_sentinel s;
6076 }
6077 }
6079 }
6081 /* True iff T is a specialization of a variable template. */
6083 bool
6085 {
6090 }
6092 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6093 template declaration, or a TYPE_DECL for an alias declaration. */
6095 bool
6097 {
6105 }
6107 /* Return TRUE iff T is a specialization of an alias template. */
6109 bool
6111 {
6112 /* It's an alias template specialization if it's an alias and its
6113 TYPE_NAME is a specialization of a primary template. */
6119 }
6121 /* An alias template is complex from a SFINAE perspective if a template-id
6122 using that alias can be ill-formed when the expansion is not, as with
6123 the void_t template. We determine this by checking whether the
6124 expansion for the alias template uses all its template parameters. */
6126 struct uses_all_template_parms_data
6127 {
6130 };
6132 static int
6134 {
6142 }
6144 static bool
6146 {
6161 }
6163 /* Return TRUE iff T is a specialization of a complex alias template with
6164 dependent template-arguments. */
6166 bool
6168 {
6181 }
6183 /* Return the number of innermost template parameters in TMPL. */
6185 static int
6187 {
6190 }
6192 /* Return either TMPL or another template that it is equivalent to under DR
6193 1286: An alias that just changes the name of a template is equivalent to
6194 the other template. */
6196 static tree
6198 {
6201 {
6202 /* Determine if the alias is equivalent to an underlying template. */
6214 tree alias_args = INNERMOST_TEMPLATE_ARGS
6219 /* Alias is equivalent. Strip it and repeat. */
6221 }
6224 }
6226 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6227 must be a reference-to-function or a pointer-to-function type, as specified
6228 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6229 and check that the resulting function has external linkage. */
6231 static tree
6233 tsubst_flags_t complain)
6234 {
6237 linkage_kind linkage;
6252 /* [temp.arg.nontype]/1
6254 A template-argument for a non-type, non-template template-parameter
6255 shall be one of:
6256 [...]
6257 -- the address of an object or function with external [C++11: or
6258 internal] linkage. */
6261 {
6263 {
6269 else
6272 }
6274 }
6278 {
6280 {
6285 else
6289 }
6291 }
6293 accept:
6295 {
6298 else
6300 }
6305 }
6307 /* Subroutine of convert_nontype_argument.
6308 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6309 Emit an error otherwise. */
6311 static bool
6313 tsubst_flags_t complain)
6314 {
6331 {
6336 else
6338 }
6340 }
6342 /* Returns TRUE iff the address of OP is value-dependent.
6344 14.6.2.4 [temp.dep.temp]:
6345 A non-integral non-type template-argument is dependent if its type is
6346 dependent or it has either of the following forms
6347 qualified-id
6348 & qualified-id
6349 and contains a nested-name-specifier which specifies a class-name that
6350 names a dependent type.
6352 We generalize this to just say that the address of a member of a
6353 dependent class is value-dependent; the above doesn't cover the
6354 address of a static data member named with an unqualified-id. */
6356 static bool
6358 {
6359 /* We could use get_inner_reference here, but there's no need;
6360 this is only relevant for template non-type arguments, which
6361 can only be expressed as &id-expression. */
6363 {
6367 }
6370 }
6372 /* The next set of functions are used for providing helpful explanatory
6373 diagnostics for failed overload resolution. Their messages should be
6374 indented by two spaces for consistency with the messages in
6375 call.c */
6377 static int
6379 {
6381 }
6383 /* Other failure functions should call this one, to provide a single function
6384 for setting a breakpoint on. */
6386 static int
6388 {
6390 }
6392 static int
6394 {
6399 }
6401 static int
6403 {
6409 }
6411 static int
6413 {
6417 }
6419 static int
6421 {
6424 " template parameter %qD is not a parameter pack, but "
6428 }
6430 static int
6432 {
6435 " template argument %qE does not match "
6439 }
6441 static int
6443 {
6447 }
6449 static int
6451 {
6457 }
6459 static int
6461 {
6463 {
6468 else
6470 " deduced conflicting values for non-type parameter "
6472 }
6474 }
6476 static int
6478 {
6481 " variable-sized array type %qT is not "
6483 arg);
6485 }
6487 static int
6489 {
6493 arg);
6495 }
6497 static int
6499 {
6501 {
6507 else
6512 }
6514 }
6516 static int
6518 {
6520 }
6522 static int
6525 {
6527 }
6529 static int
6532 {
6538 }
6540 static int
6543 {
6546 {
6554 }
6556 }
6558 static int
6560 {
6563 " template parameters of a template template argument are "
6566 }
6568 static int
6570 {
6576 }
6578 static int
6580 {
6585 }
6587 /* Attempt to convert the non-type template parameter EXPR to the
6588 indicated TYPE. If the conversion is successful, return the
6589 converted value. If the conversion is unsuccessful, return
6590 NULL_TREE if we issued an error message, or error_mark_node if we
6591 did not. We issue error messages for out-and-out bad template
6592 parameters, but not simply because the conversion failed, since we
6593 might be just trying to do argument deduction. Both TYPE and EXPR
6594 must be non-dependent.
6596 The conversion follows the special rules described in
6597 [temp.arg.nontype], and it is much more strict than an implicit
6598 conversion.
6600 This function is called twice for each template argument (see
6601 lookup_template_class for a more accurate description of this
6602 problem). This means that we need to handle expressions which
6603 are not valid in a C++ source, but can be created from the
6604 first call (for instance, casts to perform conversions). These
6605 hacks can go away after we fix the double coercion problem. */
6607 static tree
6609 {
6610 tree expr_type;
6614 /* Detect immediately string literals as invalid non-type argument.
6615 This special-case is not needed for correctness (we would easily
6616 catch this later), but only to provide better diagnostic for this
6617 common user mistake. As suggested by DR 100, we do not mention
6618 linkage issues in the diagnostic as this is not the point. */
6619 /* FIXME we're making this OK. */
6621 {
6627 }
6629 /* Add the ADDR_EXPR now for the benefit of
6630 value_dependent_expression_p. */
6633 {
6637 }
6639 /* If we are in a template, EXPR may be non-dependent, but still
6640 have a syntactic, rather than semantic, form. For example, EXPR
6641 might be a SCOPE_REF, rather than the VAR_DECL to which the
6642 SCOPE_REF refers. Preserving the qualifying scope is necessary
6643 so that access checking can be performed when the template is
6644 instantiated -- but here we need the resolved form so that we can
6645 convert the argument. */
6657 /* If the argument is non-dependent, perform any conversions in
6658 non-dependent context as well. */
6666 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6667 to a non-type argument of "nullptr". */
6671 /* In C++11, integral or enumeration non-type template arguments can be
6672 arbitrary constant expressions. Pointer and pointer to
6673 member arguments can be general constant expressions that evaluate
6674 to a null value, but otherwise still need to be of a specific form. */
6676 {
6678 /* A PTRMEM_CST is already constant, and a valid template
6679 argument for a parameter of pointer to member type, we just want
6680 to leave it in that form rather than lower it to a
6684 {
6685 /* C++17: A template-argument for a non-type template-parameter shall
6686 be a converted constant expression (8.20) of the type of the
6687 template-parameter. */
6690 /* Make sure we return NULL_TREE only if we have really issued
6691 an error, as described above. */
6695 }
6697 {
6702 }
6703 }
6707 else
6710 /* HACK: Due to double coercion, we can get a
6711 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6712 which is the tree that we built on the first call (see
6713 below when coercing to reference to object or to reference to
6714 function). We just strip everything and get to the arg.
6715 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6716 for examples. */
6718 {
6724 {
6725 /* ??? Maybe we could use convert_from_reference here, but we
6726 would need to relax its constraints because the NOP_EXPR
6727 could actually change the type to something more cv-qualified,
6728 and this is not folded by convert_from_reference. */
6733 && (same_type_ignoring_top_level_qualifiers_p
6736 {
6739 }
6740 }
6741 }
6743 /* [temp.arg.nontype]/5, bullet 1
6745 For a non-type template-parameter of integral or enumeration type,
6746 integral promotions (_conv.prom_) and integral conversions
6747 (_conv.integral_) are applied. */
6749 {
6751 {
6756 }
6761 /* Notice that there are constant expressions like '4 % 0' which
6762 do not fold into integer constants. */
6765 {
6767 {
6771 else
6777 /* else cxx_constant_value complained but gave us
6778 a real constant, so go ahead. */
6780 {
6781 /* Some assemble time constant expressions like
6782 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6783 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6784 as we can emit them into .rodata initializers of
6785 variables, yet they can't fold into an INTEGER_CST at
6786 compile time. Refuse them here. */
6791 }
6792 }
6793 else
6795 }
6797 /* Avoid typedef problems. */
6800 }
6801 /* [temp.arg.nontype]/5, bullet 2
6803 For a non-type template-parameter of type pointer to object,
6804 qualification conversions (_conv.qual_) and the array-to-pointer
6805 conversion (_conv.array_) are applied. */
6807 {
6810 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6811 decay_conversion or an explicit cast. If it's a problematic cast,
6812 we'll complain about it below. */
6814 {
6819 {
6822 }
6823 }
6825 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6827 A template-argument for a non-type, non-template template-parameter
6828 shall be one of: [...]
6830 -- the name of a non-type template-parameter;
6831 -- the address of an object or function with external linkage, [...]
6832 expressed as "& id-expression" where the & is optional if the name
6833 refers to a function or array, or if the corresponding
6834 template-parameter is a reference.
6836 Here, we do not care about functions, as they are invalid anyway
6837 for a parameter of type pointer-to-object. */
6840 /* Non-type template parameters are OK. */
6841 ;
6845 {
6847 {
6850 "because %qD is a variable, not the address of "
6853 }
6855 {
6861 }
6862 /* Other values, like integer constants, might be valid
6863 non-type arguments of some other type. */
6865 }
6866 else
6867 {
6871 {
6876 }
6878 {
6884 }
6887 {
6892 }
6893 /* C++17: For a non-type template-parameter of reference or pointer
6894 type, the value of the constant expression shall not refer to (or
6895 for a pointer type, shall not be the address of):
6896 * a subobject (4.5),
6897 * a temporary object (15.2),
6898 * a string literal (5.13.5),
6899 * the result of a typeid expression (8.2.8), or
6900 * a predefined __func__ variable (11.4.1). */
6902 {
6905 decl);
6907 }
6911 {
6916 }
6918 {
6922 decl);
6924 }
6925 }
6932 }
6933 /* [temp.arg.nontype]/5, bullet 3
6935 For a non-type template-parameter of type reference to object, no
6936 conversions apply. The type referred to by the reference may be more
6937 cv-qualified than the (otherwise identical) type of the
6938 template-argument. The template-parameter is bound directly to the
6939 template-argument, which must be an lvalue. */
6941 {
6943 expr_type))
6947 {
6952 }
6955 {
6960 }
6962 /* [temp.arg.nontype]/1
6964 A template-argument for a non-type, non-template template-parameter
6965 shall be one of: [...]
6967 -- the address of an object or function with external linkage. */
6970 {
6973 {
6976 "because a reference variable does not have a constant "
6979 }
6980 }
6984 /* OK, dependent reference. We don't want to ask whether a DECL is
6986 else
6987 {
6989 {
6995 }
6997 /* DR 1155 allows internal linkage in C++11 and up. */
7000 {
7006 }
7009 }
7013 }
7014 /* [temp.arg.nontype]/5, bullet 4
7016 For a non-type template-parameter of type pointer to function, only
7017 the function-to-pointer conversion (_conv.func_) is applied. If the
7018 template-argument represents a set of overloaded functions (or a
7019 pointer to such), the matching function is selected from the set
7020 (_over.over_). */
7022 {
7023 /* If the argument is a template-id, we might not have enough
7024 context information to decay the pointer. */
7026 {
7030 }
7033 /* Null pointer values are OK in C++11. */
7039 }
7040 /* [temp.arg.nontype]/5, bullet 5
7042 For a non-type template-parameter of type reference to function, no
7043 conversions apply. If the template-argument represents a set of
7044 overloaded functions, the matching function is selected from the set
7045 (_over.over_). */
7047 {
7049 {
7051 {
7056 }
7058 }
7063 }
7064 /* [temp.arg.nontype]/5, bullet 6
7066 For a non-type template-parameter of type pointer to member function,
7067 no conversions apply. If the template-argument represents a set of
7068 overloaded member functions, the matching member function is selected
7069 from the set (_over.over_). */
7071 {
7076 /* [temp.arg.nontype] bullet 1 says the pointer to member
7077 expression must be a pointer-to-member constant. */
7082 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7083 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7086 }
7087 /* [temp.arg.nontype]/5, bullet 7
7089 For a non-type template-parameter of type pointer to data member,
7090 qualification conversions (_conv.qual_) are applied. */
7092 {
7093 /* [temp.arg.nontype] bullet 1 says the pointer to member
7094 expression must be a pointer-to-member constant. */
7102 }
7104 {
7106 {
7111 }
7113 }
7114 /* A template non-type parameter must be one of the above. */
7115 else
7118 /* Sanity check: did we actually convert the argument to the
7119 right type? */
7123 }
7125 /* Subroutine of coerce_template_template_parms, which returns 1 if
7126 PARM_PARM and ARG_PARM match using the rule for the template
7127 parameters of template template parameters. Both PARM and ARG are
7128 template parameters; the rest of the arguments are the same as for
7129 coerce_template_template_parms.
7130 */
7131 static int
7133 tree arg,
7134 tsubst_flags_t complain,
7135 tree in_decl,
7136 tree outer_args)
7137 {
7146 {
7148 /* We encounter instantiations of templates like
7149 template <template <template <class> class> class TT>
7150 class C; */
7151 {
7158 }
7159 /* Fall through. */
7164 /* Argument is a parameter pack but parameter is not. */
7169 /* The tsubst call is used to handle cases such as
7171 template <int> class C {};
7172 template <class T, template <T> class TT> class D {};
7173 D<int, C> d;
7175 i.e. the parameter list of TT depends on earlier parameters. */
7177 {
7182 }
7186 /* Argument is a parameter pack but parameter is not. */
7193 }
7196 }
7198 /* Coerce template argument list ARGLIST for use with template
7199 template-parameter TEMPL. */
7201 static tree
7203 tsubst_flags_t complain)
7204 {
7205 /* Consider an example where a template template parameter declared as
7207 template <class T, class U = std::allocator<T> > class TT
7209 The template parameter level of T and U are one level larger than
7210 of TT. To proper process the default argument of U, say when an
7211 instantiation `TT<int>' is seen, we need to build the full
7212 arguments containing {int} as the innermost level. Outer levels,
7213 available when not appearing as default template argument, can be
7214 obtained from the arguments of the enclosing template.
7216 Suppose that TT is later substituted with std::vector. The above
7217 instantiation is `TT<int, std::allocator<T> >' with TT at
7218 level 1, and T at level 2, while the template arguments at level 1
7219 becomes {std::vector} and the inner level 2 is {int}. */
7223 {
7225 /* We want arguments for the partial specialization, not arguments for
7226 the primary template. */
7228 else
7230 }
7232 {
7233 /* This is an argument of the current template, so we haven't set
7234 DECL_CONTEXT yet. */
7235 tree relevant_template_parms;
7237 /* Parameter levels that are greater than the level of the given
7238 template template parm are irrelevant. */
7245 }
7252 complain,
7255 }
7257 /* A cache of template template parameters with match-all default
7258 arguments. */
7260 static void
7262 {
7266 }
7267 static tree
7269 {
7274 }
7276 /* T is a bound template template-parameter. Copy its arguments into default
7277 arguments of the template template-parameter's template parameters. */
7279 static tree
7281 {
7304 {
7307 {
7310 }
7311 }
7315 }
7317 /* ARG is a bound potential template template-argument, and PARGS is a list
7318 of arguments for the corresponding template template-parameter. Adjust
7319 PARGS as appropriate for application to ARG's template, and if ARG is a
7320 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7321 arguments to the template template parameter. */
7323 static tree
7325 {
7329 {
7330 /* When comparing two template template-parameters in partial ordering,
7331 rewrite the one currently being used as an argument to have default
7332 arguments for all parameters. */
7338 }
7339 else
7340 {
7341 tree aparms
7346 }
7349 }
7351 /* Subroutine of unify for the case when PARM is a
7352 BOUND_TEMPLATE_TEMPLATE_PARM. */
7354 static int
7357 {
7361 /* The template template parm might be variadic and the argument
7362 not, so flatten both argument lists. */
7367 {
7368 /* In keeping with P0522R0, adjust P's template arguments
7369 to apply to A's template; then flatten it again. */
7378 /* If the P0522 adjustment eliminated a pack expansion, deduce
7379 empty packs. */
7385 }
7386 else
7387 {
7388 /* Deduce arguments T, i from TT<T> or TT<i>.
7389 We check each element of PARMVEC and ARGVEC individually
7390 rather than the whole TREE_VEC since they can have
7391 different number of elements, which is allowed under N2555. */
7395 /* Check if the parameters end in a pack, making them
7396 variadic. */
7403 /* If the template argument list of P contains a pack
7404 expansion that is not the last template argument, the
7405 entire template argument list is a non-deduced
7406 context. */
7424 DEDUCE_EXACT,
7427 }
7430 }
7432 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7433 template template parameters. Both PARM_PARMS and ARG_PARMS are
7434 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7435 or PARM_DECL.
7437 Consider the example:
7438 template <class T> class A;
7439 template<template <class U> class TT> class B;
7441 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7442 the parameters to A, and OUTER_ARGS contains A. */
7444 static int
7446 tree arg_parms,
7447 tsubst_flags_t complain,
7448 tree in_decl,
7449 tree outer_args)
7450 {
7462 {
7463 /* P0522R0: A template template-parameter P is at least as specialized as
7464 a template template-argument A if, given the following rewrite to two
7465 function templates, the function template corresponding to P is at
7466 least as specialized as the function template corresponding to A
7467 according to the partial ordering rules for function templates
7468 ([temp.func.order]). Given an invented class template X with the
7469 template parameter list of A (including default arguments):
7471 * Each of the two function templates has the same template parameters,
7472 respectively, as P or A.
7474 * Each function template has a single function parameter whose type is
7475 a specialization of X with template arguments corresponding to the
7476 template parameters from the respective function template where, for
7477 each template parameter PP in the template parameter list of the
7478 function template, a corresponding template argument AA is formed. If
7479 PP declares a parameter pack, then AA is the pack expansion
7480 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7482 If the rewrite produces an invalid type, then P is not at least as
7483 specialized as A. */
7485 /* So coerce P's args to apply to A's parms, and then deduce between A's
7486 args and the converted args. If that succeeds, A is at least as
7487 specialized as P, so they match.*/
7494 {
7500 }
7501 }
7503 /* Determine whether we have a parameter pack at the end of the
7504 template template parameter's template parameter list. */
7506 {
7513 {
7527 }
7528 }
7534 /* Check all of the template parameters except the parameter pack at
7535 the end (if any). */
7537 {
7546 outer_args))
7549 }
7552 {
7553 /* Check each of the template parameters in the template
7554 argument against the template parameter pack at the end of
7555 the template template parameter. */
7562 {
7569 outer_args))
7571 }
7572 }
7575 }
7577 /* Verifies that the deduced template arguments (in TARGS) for the
7578 template template parameters (in TPARMS) represent valid bindings,
7579 by comparing the template parameter list of each template argument
7580 to the template parameter list of its corresponding template
7581 template parameter, in accordance with DR150. This
7582 routine can only be called after all template arguments have been
7583 deduced. It will return TRUE if all of the template template
7584 parameter bindings are okay, FALSE otherwise. */
7585 bool
7587 {
7591 /* We're dealing with template parms in this process. */
7597 {
7602 {
7607 {
7608 /* Look inside the argument pack. */
7611 }
7614 {
7618 /* Extract the next argument from the argument
7619 pack. */
7623 /* Look at the pattern of the pack expansion. */
7626 /* Extract the template parameters from the template
7627 argument. */
7633 /* Verify that we can coerce the template template
7634 parameters from the template argument to the template
7635 parameter. This requires an exact match. */
7637 && !coerce_template_template_parms
7639 targ_parms,
7640 tf_none,
7641 tparm,
7642 targs))
7643 {
7646 }
7647 }
7648 }
7649 }
7651 out:
7655 }
7657 /* Since type attributes aren't mangled, we need to strip them from
7658 template type arguments. */
7660 static tree
7662 {
7672 }
7674 /* And from inside dependent non-type arguments like sizeof(Type). */
7676 static tree
7678 {
7688 }
7690 // A template declaration can be substituted for a constrained
7691 // template template parameter only when the argument is more
7692 // constrained than the parameter.
7693 static bool
7695 {
7698 /* For now, allow constrained template template arguments
7699 and unconstrained template template parameters. */
7705 // If the template parameter is constrained, we need to rewrite its
7706 // constraints in terms of the ARG's template parameters. This ensures
7707 // that all of the template parameter types will have the same depth.
7708 //
7709 // Note that this is only valid when coerce_template_template_parm is
7710 // true for the innermost template parameters of PARM and ARG. In other
7711 // words, because coercion is successful, this conversion will be valid.
7713 {
7720 }
7723 }
7725 // Convert a placeholder argument into a binding to the original
7726 // parameter. The original parameter is saved as the TREE_TYPE of
7727 // ARG.
7730 {
7733 }
7735 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7736 because one of them is dependent. But we need to represent the
7737 conversion for the benefit of cp_tree_equal. */
7739 static tree
7741 {
7742 /* Auto parms get no conversion. */
7745 /* We don't need or want to add this conversion now if we're going to use the
7746 argument for deduction. */
7758 }
7760 /* Convert the indicated template ARG as necessary to match the
7761 indicated template PARM. Returns the converted ARG, or
7762 error_mark_node if the conversion was unsuccessful. Error and
7763 warning messages are issued under control of COMPLAIN. This
7764 conversion is for the Ith parameter in the parameter list. ARGS is
7765 the full set of template arguments deduced so far. */
7767 static tree
7769 tree arg,
7770 tree args,
7771 tsubst_flags_t complain,
7773 tree in_decl)
7774 {
7775 tree orig_arg;
7776 tree val;
7782 /* Trivially convert placeholders. */
7791 {
7792 /* The template argument was the name of some
7793 member function. That's usually
7794 invalid, but static members are OK. In any
7795 case, grab the underlying fields/functions
7796 and issue an error later if required. */
7799 }
7807 /* When determining whether an argument pack expansion is a template,
7808 look at the pattern. */
7812 /* Deal with an injected-class-name used as a template template arg. */
7814 {
7817 {
7827 }
7828 }
7830 is_tmpl_type =
7846 {
7848 {
7852 }
7855 "to refer to a type member of a template parameter, "
7860 typename_type,
7861 complain);
7864 }
7866 {
7868 {
7870 {
7882 else
7885 }
7886 }
7888 }
7890 {
7892 {
7899 else
7902 }
7904 }
7907 /* We already did the appropriate conversion when packing args. */
7910 {
7912 {
7914 /* The number of argument required is not known yet.
7915 Just accept it for now. */
7917 else
7918 {
7920 tree argparm;
7922 /* Strip alias templates that are equivalent to another
7923 template. */
7929 args))
7930 {
7933 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7934 TEMPLATE_DECL. */
7936 {
7941 }
7942 }
7943 else
7944 {
7946 {
7953 }
7956 }
7958 // Check that the constraints are compatible before allowing the
7959 // substitution.
7962 {
7964 {
7970 }
7972 }
7973 }
7974 }
7975 else
7977 /* We only form one instance of each template specialization.
7978 Therefore, if we use a non-canonical variant (i.e., a
7979 typedef), any future messages referring to the type will use
7980 the typedef, which is confusing if those future uses do not
7981 themselves also use the typedef. */
7984 }
7985 else
7986 {
7991 /* We don't have enough levels of args to do any substitution. This
7994 {
7998 }
7999 else
8007 /* We used to call digest_init here. However, digest_init
8008 will report errors, which we don't want when complain
8009 is zero. More importantly, digest_init will try too
8010 hard to convert things: for example, `0' should not be
8011 converted to pointer type at this point according to
8012 the standard. Accepting this is not merely an
8013 extension, since deciding whether or not these
8014 conversions can occur is part of determining which
8015 function template to call, or whether a given explicit
8016 argument specification is valid. */
8018 else
8019 {
8022 }
8032 {
8033 /* Reject template arguments that are references to built-in
8034 functions with no library fallbacks. */
8043 }
8046 {
8047 /* Strip typedefs from the SCOPE_REF. */
8050 complain);
8053 }
8054 }
8057 }
8059 /* Coerces the remaining template arguments in INNER_ARGS (from
8060 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8061 Returns the coerced argument pack. PARM_IDX is the position of this
8062 parameter in the template parameter list. ARGS is the original
8063 template argument list. */
8064 static tree
8067 tree args,
8068 tree inner_args,
8070 tree new_args,
8072 tree in_decl,
8073 tsubst_flags_t complain)
8074 {
8077 tree packed_args;
8078 tree argument_pack;
8085 {
8086 /* When the template parameter is a non-type template parameter pack
8087 or template template parameter pack whose type or template
8088 parameters use parameter packs, we know exactly how many arguments
8089 we are looking for. Build a vector of the instantiated decls for
8090 these template parameters in PACKED_PARMS. */
8091 /* We can't use make_pack_expansion here because it would interpret a
8092 _DECL as a use rather than a declaration. */
8106 /* If we're doing a partial instantiation of a member template,
8107 verify that all of the types used for the non-type
8108 template parameter pack are, in fact, valid for non-type
8109 template parameters. */
8112 {
8115 {
8119 }
8120 /* We don't know how many args we have yet, just
8121 use the unconverted ones for now. */
8123 }
8126 }
8127 /* Check if we have a placeholder pack, which indicates we're
8128 in the context of a introduction list. In that case we want
8129 to match this pack to the single placeholder. */
8133 {
8136 }
8137 else
8140 /* Convert the remaining arguments, which will be a part of the
8141 parameter pack "parm". */
8144 {
8150 {
8151 /* Once we've packed as many args as we have types, stop. */
8155 /* We don't know how many args we have yet, just
8156 use the unconverted ones for now. */
8158 else
8160 }
8163 {
8166 }
8167 else
8170 in_decl);
8174 }
8178 {
8183 }
8188 else
8189 {
8192 }
8199 }
8201 /* Returns the number of pack expansions in the template argument vector
8202 ARGS. */
8204 static int
8206 {
8211 {
8215 }
8217 }
8219 /* Convert all template arguments to their appropriate types, and
8220 return a vector containing the innermost resulting template
8221 arguments. If any error occurs, return error_mark_node. Error and
8222 warning messages are issued under control of COMPLAIN.
8224 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8225 for arguments not specified in ARGS. Otherwise, if
8226 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8227 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8228 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8229 ARGS. */
8231 static tree
8233 tree args,
8234 tree in_decl,
8235 tsubst_flags_t complain,
8238 {
8240 tree orig_inner_args;
8241 tree inner_args;
8242 tree new_args;
8243 tree new_inner_args;
8247 /* When used as a boolean value, indicates whether this is a
8248 variadic template parameter list. Since it's an int, we can also
8249 subtract it from nparms to get the number of non-variadic
8250 parameters. */
8255 /* Adjustment to nparms for fixed parameter packs. */
8260 /* Likewise for parameters with default arguments. */
8268 /* Determine if there are any parameter packs or default arguments. */
8270 {
8278 }
8281 /* If there are no parameters that follow a parameter pack, we need to
8282 expand any argument packs so that we can deduce a parameter pack from
8283 some non-packed args followed by an argument pack, as in variadic85.C.
8284 If there are such parameters, we need to leave argument packs intact
8285 so the arguments are assigned properly. This can happen when dealing
8286 with a nested class inside a partial specialization of a class
8287 template, as in variadic92.C, or when deducing a template parameter pack
8288 from a sub-declarator, as in variadic114.C. */
8292 /* Count any pack expansion args. */
8298 && require_all_args
8299 && !variadic_args_p
8300 && (!use_default_args
8303 {
8304 bad_nargs:
8306 {
8308 {
8312 }
8313 else
8320 }
8323 }
8324 /* We can't pass a pack expansion to a non-pack parameter of an alias
8325 template (DR 1430). */
8329 && variadic_args_p
8331 {
8333 {
8335 {
8341 {
8344 "pack expansion argument for non-pack parameter "
8346 else
8348 "pack expansion argument for non-pack parameter "
8352 }
8353 }
8355 found:;
8356 }
8358 }
8360 /* We need to evaluate the template arguments, even though this
8361 template-id may be nested within a "sizeof". */
8370 {
8371 tree arg;
8372 tree parm;
8374 /* Get the Ith template parameter. */
8378 {
8381 }
8383 /* Calculate the next argument. */
8386 else
8391 {
8392 /* Some arguments will be placed in the
8393 template parameter pack PARM. */
8400 {
8401 /* We don't know how many args we have yet, just use the
8402 unconverted (and still packed) ones for now. */
8406 }
8410 /* Store this argument. */
8412 {
8413 lost++;
8414 /* We are done with all of the arguments. */
8417 }
8418 else
8419 {
8423 {
8426 }
8427 }
8430 }
8432 {
8434 {
8435 /* "If every valid specialization of a variadic template
8436 requires an empty template parameter pack, the template is
8437 ill-formed, no diagnostic required." So check that the
8438 pattern works with this parameter. */
8443 in_decl);
8445 {
8450 }
8452 /* Recover from missing typename. */
8456 /* We don't know how many args we have yet, just
8457 use the unconverted ones for now. */
8461 }
8462 }
8464 {
8465 /* There must be a default arg in this case. */
8468 /* The position of the first default template argument,
8469 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8470 Record that. */
8474 }
8475 else
8479 {
8482 }
8484 {
8485 /* This can occur if there was an error in the template
8486 parameter list itself (which we would already have
8487 reported) that we are trying to recover from, e.g., a class
8488 template with a parameter list such as
8489 template<typename..., typename> (cpp0x/variadic150.C). */
8492 /* This can also happen with a fixed parameter pack (71834). */
8495 }
8496 else
8502 lost++;
8504 }
8509 {
8510 /* If we had fixed parameter packs, we didn't know how many arguments we
8511 actually needed earlier; now we do. */
8515 }
8518 {
8519 /* We had some pack expansion arguments that will only work if the packs
8520 are empty, but wait until instantiation time to complain.
8521 See variadic-ttp3.C. */
8531 }
8534 {
8537 }
8544 }
8546 /* Convert all template arguments to their appropriate types, and
8547 return a vector containing the innermost resulting template
8548 arguments. If any error occurs, return error_mark_node. Error and
8549 warning messages are not issued.
8551 Note that no function argument deduction is performed, and default
8552 arguments are used to fill in unspecified arguments. */
8553 tree
8555 {
8557 }
8559 /* Convert all template arguments to their appropriate type, and
8560 instantiate default arguments as needed. This returns a vector
8561 containing the innermost resulting template arguments, or
8562 error_mark_node if unsuccessful. */
8563 tree
8565 tsubst_flags_t complain)
8566 {
8568 }
8570 /* Like coerce_template_parms. If PARMS represents all template
8571 parameters levels, this function returns a vector of vectors
8572 representing all the resulting argument levels. Note that in this
8573 case, only the innermost arguments are coerced because the
8574 outermost ones are supposed to have been coerced already.
8576 Otherwise, if PARMS represents only (the innermost) vector of
8577 parameters, this function returns a vector containing just the
8578 innermost resulting arguments. */
8580 static tree
8582 tree args,
8583 tree in_decl,
8584 tsubst_flags_t complain,
8587 {
8590 tree coerced_args;
8593 {
8595 tree level;
8601 {
8602 tree l;
8606 require_all_args,
8607 use_default_args);
8608 else
8615 }
8616 }
8617 else
8620 require_all_args,
8621 use_default_args);
8623 }
8625 /* Returns 1 if template args OT and NT are equivalent. */
8627 int
8629 {
8638 /* For member templates */
8647 {
8664 }
8668 {
8671 /* Don't treat an alias template specialization with dependent
8672 arguments as equivalent to its underlying type when used as a
8673 template argument; we need them to be distinct so that we
8674 substitute into the specialization arguments at instantiation
8675 time. And aliases can't be equivalent without being ==, so
8676 we don't need to look any deeper.
8678 During partial ordering, however, we need to treat them normally so
8679 that we can order uses of the same alias with different
8680 cv-qualification (79960). */
8684 else
8686 }
8689 else
8690 {
8691 /* Try to treat a template non-type argument that has been converted
8692 to the parameter type as equivalent to one that hasn't yet. */
8705 }
8706 }
8708 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8709 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8710 NEWARG_PTR with the offending arguments if they are non-NULL. */
8712 int
8716 {
8729 {
8734 {
8740 }
8741 }
8743 }
8747 {
8749 }
8751 /* Implement a freelist interface for objects of type T.
8753 Head is a separate object, rather than a regular member, so that we
8754 can define it as a GTY deletable pointer, which is highly
8755 desirable. A data member could be declared that way, but then the
8756 containing object would implicitly get GTY((user)), which would
8757 prevent us from instantiating freelists as global objects.
8758 Although this way we can create freelist global objects, they're
8759 such thin wrappers that instantiating temporaries at every use
8760 loses nothing and saves permanent storage for the freelist object.
8762 Member functions next, anew, poison and reinit have default
8763 implementations that work for most of the types we're interested
8764 in, but if they don't work for some type, they should be explicitly
8765 specialized. See the comments before them for requirements, and
8766 the example specializations for the tree_list_freelist. */
8768 class freelist
8769 {
8770 /* Return the next object in a chain. We could just do type
8771 punning, but if we access the object with its underlying type, we
8772 avoid strict-aliasing trouble. This needs only work between
8773 poison and reinit. */
8776 /* Return a newly allocated, uninitialized or minimally-initialized
8777 object of type T. Any initialization performed by anew should
8778 either remain across the life of the object and the execution of
8779 poison, or be redone by reinit. */
8782 /* Optionally scribble all over the bits holding the object, so that
8783 they become (mostly?) uninitialized memory. This is called while
8784 preparing to make the object part of the free list. */
8789 #ifdef ENABLE_GC_CHECKING
8790 /* Poison the data, to indicate the data is garbage. */
8793 #endif
8794 /* Let valgrind know the object is free. */
8797 /* Let valgrind know the next portion of the object is available,
8798 but uninitialized. */
8800 }
8802 /* Bring an object that underwent at least one lifecycle after anew
8803 and before the most recent free and poison, back to a usable
8804 state, reinitializing whatever is needed for it to be
8805 functionally equivalent to an object just allocated and returned
8806 by anew. This may poison or clear the next field, used by
8807 freelist housekeeping after poison was called. */
8811 #ifdef ENABLE_GC_CHECKING
8813 #endif
8814 /* Let valgrind know the entire object is available, but
8815 uninitialized. */
8817 }
8819 /* Reference a GTY-deletable pointer that points to the first object
8820 in the free list proper. */
8823 /* Construct a freelist object chaining objects off of HEAD. */
8826 /* Add OBJ to the free object list. The former head becomes OBJ's
8827 successor. */
8829 {
8833 }
8835 /* Take an object from the free list, if one is available, or
8836 allocate a new one. Objects taken from the free list should be
8837 regarded as filled with garbage, except for bits that are
8838 configured to be preserved across free and alloc. */
8840 {
8842 {
8847 }
8848 else
8850 }
8851 };
8853 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8854 want to allocate a TREE_LIST using the usual interface, and ensure
8855 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8856 build_tree_list logic in reinit, so this could go out of sync. */
8860 {
8862 }
8864 inline tree
8866 {
8868 }
8872 {
8878 #ifdef ENABLE_GC_CHECKING
8881 /* Poison the data, to indicate the data is garbage. */
8884 #endif
8885 /* Let valgrind know the object is free. */
8887 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8891 #ifdef ENABLE_GC_CHECKING
8893 /* Keep TREE_CHAIN functional. */
8895 #else
8897 #endif
8898 }
8902 {
8905 #ifdef ENABLE_GC_CHECKING
8909 #endif
8911 /* Let valgrind know the entire object is available, but
8912 uninitialized. */
8915 #ifdef ENABLE_GC_CHECKING
8917 #else
8919 #endif
8920 }
8922 /* Point to the first object in the TREE_LIST freelist. */
8924 /* Return the/an actual TREE_LIST freelist. */
8927 {
8929 }
8931 /* Point to the first object in the tinst_level freelist. */
8933 /* Return the/an actual tinst_level freelist. */
8936 {
8938 }
8940 /* Point to the first object in the pending_template freelist. */
8942 /* Return the/an actual pending_template freelist. */
8945 {
8947 }
8949 /* Build the TREE_LIST object out of a split list, store it
8950 permanently, and return it. */
8951 tree
8953 {
8962 }
8966 /* Increment OBJ's refcount unless it is already infinite. */
8969 {
8973 }
8975 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8976 void
8978 {
8982 }
8984 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8985 OBJ's DECL and OBJ, and start over with the tinst_level object that
8986 used to be referenced by OBJ's NEXT. */
8987 static void
8989 {
8993 {
8997 }
8998 }
9000 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9001 and of the former PTR. Omitting the second argument is equivalent
9002 to passing (T*)NULL; this is allowed because passing the
9003 zero-valued integral constant NULL confuses type deduction and/or
9004 overload resolution. */
9006 static void
9008 {
9012 }
9014 static void
9016 {
9026 /* We are called both from instantiate_decl, where we've already had a
9027 tinst_level pushed, and instantiate_template, where we haven't.
9028 Compensate. */
9030 level = !current_tinst_level
9042 else
9051 }
9054 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9055 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9056 documentation for TEMPLATE_ID_EXPR. */
9058 tree
9060 {
9061 tree type;
9069 {
9072 }
9075 {
9077 unknown_type_node,
9079 arglist);
9081 }
9088 }
9090 /* Within the scope of a template class S<T>, the name S gets bound
9091 (in build_self_reference) to a TYPE_DECL for the class, not a
9092 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9093 or one of its enclosing classes, and that type is a template,
9094 return the associated TEMPLATE_DECL. Otherwise, the original
9095 DECL is returned.
9097 Also handle the case when DECL is a TREE_LIST of ambiguous
9098 injected-class-names from different bases. */
9100 tree
9102 {
9106 /* DR 176: A lookup that finds an injected-class-name (10.2
9107 [class.member.lookup]) can result in an ambiguity in certain cases
9108 (for example, if it is found in more than one base class). If all of
9109 the injected-class-names that are found refer to specializations of
9110 the same class template, and if the name is followed by a
9111 template-argument-list, the reference refers to the class template
9112 itself and not a specialization thereof, and is not ambiguous. */
9114 {
9117 {
9123 }
9126 else
9128 }
9134 }
9136 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9137 parameters, find the desired type.
9139 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9141 IN_DECL, if non-NULL, is the template declaration we are trying to
9142 instantiate.
9144 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9145 the class we are looking up.
9147 Issue error and warning messages under control of COMPLAIN.
9149 If the template class is really a local class in a template
9150 function, then the FUNCTION_CONTEXT is the function in which it is
9151 being instantiated.
9153 ??? Note that this function is currently called *twice* for each
9154 template-id: the first time from the parser, while creating the
9155 incomplete type (finish_template_type), and the second type during the
9156 real instantiation (instantiate_template_class). This is surely something
9157 that we want to avoid. It also causes some problems with argument
9158 coercion (see convert_nontype_argument for more information on this). */
9160 static tree
9163 {
9165 tree t;
9168 spec_entry elt;
9169 hashval_t hash;
9172 {
9176 else
9177 {
9184 }
9187 }
9189 {
9192 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9193 an implicit typename for the second A. Deal with it. */
9198 {
9201 }
9202 }
9205 {
9208 }
9210 {
9214 }
9216 {
9219 }
9221 /* Issue an error message if we didn't find a template. */
9223 {
9227 }
9230 /* Make sure it's a user visible template, if it was named by
9231 the user. */
9234 {
9236 {
9240 }
9242 }
9246 /* An alias that just changes the name of a template is equivalent to the
9247 other template, so if any of the arguments are pack expansions, strip
9248 the alias to avoid problems with a pack expansion passed to a non-pack
9249 alias template parameter (DR 1430). */
9254 {
9255 tree parm;
9264 }
9265 else
9266 {
9268 tree gen_tmpl;
9269 tree type_decl;
9277 /* An error occurred while building the template TEMPL, and a
9278 diagnostic has most certainly been emitted for that
9279 already. Let's propagate that error. */
9288 {
9289 /* We've been given an incomplete set of template arguments.
9290 For example, given:
9292 template <class T> struct S1 {
9293 template <class U> struct S2 {};
9294 template <class U> struct S2<U*> {};
9295 };
9297 we will be called with an ARGLIST of `U*', but the
9298 TEMPLATE will be `template <class T> template
9299 <class U> struct S1<T>::S2'. We must fill in the missing
9300 arguments. */
9304 }
9306 /* Now we should have enough arguments. */
9309 /* From here on, we're only interested in the most general
9310 template. */
9312 /* Calculate the BOUND_ARGS. These will be the args that are
9313 actually tsubst'd into the definition to create the
9314 instantiation. */
9316 complain,
9321 /* We were unable to bind the arguments. */
9324 /* In the scope of a template class, explicit references to the
9325 template class refer to the type of the template, not any
9326 instantiation of it. For example, in:
9328 template <class T> class C { void f(C<T>); }
9330 the `C<T>' is just the same as `C'. Outside of the
9331 class, however, such a reference is an instantiation. */
9335 {
9340 }
9342 /* If we already have this specialization, return it. */
9352 /* If the the template's constraints are not satisfied,
9353 then we cannot form a valid type.
9355 Note that the check is deferred until after the hash
9356 lookup. This prevents redundant checks on previously
9357 instantiated specializations. */
9359 {
9361 {
9362 auto_diagnostic_group d;
9365 }
9367 }
9371 /* If the deduced arguments are invalid, then the binding
9372 failed. */
9376 complain))
9383 {
9388 }
9392 {
9395 }
9396 else
9405 /* Create the type. */
9407 {
9408 /* The user referred to a specialization of an alias
9409 template represented by GEN_TMPL.
9411 [temp.alias]/2 says:
9413 When a template-id refers to the specialization of an
9414 alias template, it is equivalent to the associated
9415 type obtained by substitution of its
9416 template-arguments for the template-parameters in the
9417 type-id of the alias template. */
9420 /* Note that the call above (by indirectly calling
9421 register_specialization in tsubst_decl) registers the
9422 TYPE_DECL representing the specialization of the alias
9423 template. So next time someone substitutes ARGLIST for
9424 the template parms into the alias template (GEN_TMPL),
9425 she'll get that TYPE_DECL back. */
9429 }
9431 {
9433 {
9444 }
9445 else
9446 {
9447 /* We don't want to call start_enum for this type, since
9448 the values for the enumeration constants may involve
9449 template parameters. And, no one should be interested
9450 in the enumeration constants for such a type. */
9453 }
9457 }
9459 {
9460 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9461 instantiated here. */
9469 /* A local class. Make sure the decl gets registered properly. */
9476 /* This instantiation is another name for the primary
9477 template type. Set the TYPE_CANONICAL field
9478 appropriately. */
9481 /* Some of the template arguments require structural
9482 equality testing, so this template class requires
9483 structural equality testing. */
9485 }
9486 else
9489 /* If we called start_enum or pushtag above, this information
9490 will already be set up. */
9492 {
9499 }
9500 else
9504 {
9510 {
9513 }
9514 }
9518 {
9522 {
9523 tree attributes
9531 }
9532 }
9534 /* Let's consider the explicit specialization of a member
9535 of a class template specialization that is implicitly instantiated,
9536 e.g.:
9537 template<class T>
9538 struct S
9539 {
9540 template<class U> struct M {}; //#0
9541 };
9543 template<>
9544 template<>
9545 struct S<int>::M<char> //#1
9546 {
9547 int i;
9548 };
9549 [temp.expl.spec]/4 says this is valid.
9551 In this case, when we write:
9552 S<int>::M<char> m;
9554 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9555 the one of #0.
9557 When we encounter #1, we want to store the partial instantiation
9558 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9560 For all cases other than this "explicit specialization of member of a
9561 class template", we just want to store the most general template into
9562 the CLASSTYPE_TI_TEMPLATE of M.
9564 This case of "explicit specialization of member of a class template"
9565 only happens when:
9566 1/ the enclosing class is an instantiation of, and therefore not
9567 the same as, the context of the most general template, and
9568 2/ we aren't looking at the partial instantiation itself, i.e.
9569 the innermost arguments are not the same as the innermost parms of
9570 the most general template.
9572 So it's only when 1/ and 2/ happens that we want to use the partial
9573 instantiation of the member template in lieu of its most general
9574 template. */
9578 /* the enclosing class must be an instantiation... */
9581 {
9585 tree partial_inst_args =
9592 use_partial_inst_tmpl =
9593 /*...and we must not be looking at the partial instantiation
9594 itself. */
9596 partial_inst_args);
9597 }
9600 /* This case is easy; there are no member templates involved. */
9602 else
9603 {
9604 /* This is a full instantiation of a member template. Find
9605 the partial instantiation of which this is an instance. */
9607 /* Temporarily reduce by one the number of levels in the ARGLIST
9608 so as to avoid comparing the last set of arguments. */
9612 /* FOUND is either a proper class type, or an alias
9613 template specialization. In the later case, it's a
9614 TYPE_DECL, resulting from the substituting of arguments
9615 for parameters in the TYPE_DECL of the alias template
9616 done earlier. So be careful while getting the template
9617 of FOUND. */
9619 ? found
9623 }
9625 // Build template info for the new specialization.
9634 /* Note this use of the partial instantiation so we can check it
9635 later in maybe_process_partial_specialization. */
9642 /* Now that the type has been registered on the instantiations
9643 list, we set up the enumerators. Because the enumeration
9644 constants may involve the enumeration type itself, we make
9645 sure to register the type first, and then create the
9646 constants. That way, doing tsubst_expr for the enumeration
9647 constants won't result in recursive calls here; we'll find
9648 the instantiation and exit above. */
9652 /* If the type makes use of template parameters, the
9653 code that generates debugging information will crash. */
9656 /* Possibly limit visibility based on template args. */
9663 }
9664 }
9666 /* Wrapper for lookup_template_class_1. */
9668 tree
9671 {
9672 tree ret;
9678 }
9680 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9682 tree
9684 {
9685 /* The type of the expression is NULL_TREE since the template-id could refer
9686 to an explicit or partial specialization. */
9689 /* Except that concepts are always bool. */
9692 }
9694 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9696 tree
9698 {
9702 /* We never want to return a VAR_DECL for a variable concept, since they
9703 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9718 {
9720 {
9721 auto_diagnostic_group d;
9724 }
9726 }
9728 /* If a template-id refers to a specialization of a variable
9729 concept, then the expression is true if and only if the
9730 concept's constraints are satisfied by the given template
9731 arguments.
9733 NOTE: This is an extension of Concepts Lite TS that
9734 allows constraints to be used in expressions. */
9736 {
9739 }
9742 }
9744 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9745 TARGS template args, and instantiate it if it's not dependent. */
9747 tree
9749 tsubst_flags_t complain)
9750 {
9753 {
9756 }
9759 }
9761 \f
9762 struct pair_fn_data
9763 {
9764 tree_fn_t fn;
9765 tree_fn_t any_fn;
9767 /* True when we should also visit template parameters that occur in
9768 non-deduced contexts. */
9771 };
9773 /* Called from for_each_template_parm via walk_tree. */
9775 static tree
9777 {
9784 #define WALK_SUBTREE(NODE) \
9785 do \
9786 { \
9787 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9788 pfd->include_nondeduced_p, \
9789 pfd->any_fn); \
9790 if (result) goto out; \
9791 } \
9792 while (0)
9802 {
9806 /* Fall through. */
9812 else
9822 /* Since we're not going to walk subtrees, we have to do this
9823 explicitly here. */
9825 /* Fall through. */
9828 /* Check the return type. */
9831 /* Check the parameter types. Since default arguments are not
9832 instantiated until they are needed, the TYPE_ARG_TYPES may
9833 contain expressions that involve template parameters. But,
9834 no-one should be looking at them yet. And, once they're
9835 instantiated, they don't contain template parameters, so
9836 there's no point in looking at them then, either. */
9837 {
9838 tree parm;
9843 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9844 want walk_tree walking into them itself. */
9846 }
9849 {
9853 }
9872 /* Fall through. */
9884 /* Record template parameters such as `T' inside `TT<T>'. */
9886 /* Fall through. */
9898 /* A template template parameter is encountered. */
9902 /* Already substituted template template parameter */
9907 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9908 partial instantiation. */
9920 /* If there's no type, then this thing must be some expression
9921 involving template parameters. */
9943 }
9945 #undef WALK_SUBTREE
9947 /* We didn't find any template parameters we liked. */
9948 out:
9950 }
9952 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9953 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9954 call FN with the parameter and the DATA.
9955 If FN returns nonzero, the iteration is terminated, and
9956 for_each_template_parm returns 1. Otherwise, the iteration
9957 continues. If FN never returns a nonzero value, the value
9958 returned by for_each_template_parm is 0. If FN is NULL, it is
9959 considered to be the function which always returns 1.
9961 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9962 parameters that occur in non-deduced contexts. When false, only
9963 visits those template parameters that can be deduced. */
9965 static tree
9969 tree_fn_t any_fn)
9970 {
9972 tree result;
9974 /* Set up. */
9980 /* Walk the tree. (Conceptually, we would like to walk without
9981 duplicates, but for_each_template_parm_r recursively calls
9982 for_each_template_parm, so we would need to reorganize a fair
9983 bit to use walk_tree_without_duplicates, so we keep our own
9984 visited list.) */
9987 else
9990 for_each_template_parm_r,
9994 /* Clean up. */
9996 {
9999 }
10002 }
10004 /* Returns true if T depends on any template parameter. */
10006 int
10008 {
10038 else
10039 {
10042 }
10047 }
10049 /* Returns true iff current_function_decl is an incompletely instantiated
10050 template. Useful instead of processing_template_decl because the latter
10051 is set to 0 during instantiate_non_dependent_expr. */
10053 bool
10055 {
10064 }
10066 /* Returns true if T depends on any template parameter with level LEVEL. */
10068 bool
10070 {
10073 }
10075 /* Returns true if the signature of DECL depends on any template parameter from
10076 its enclosing class. */
10078 bool
10080 {
10090 template_parm_outer_level,
10100 }
10102 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10103 ill-formed translation unit, i.e. a variable or function that isn't
10104 usable in a constant expression. */
10108 {
10113 }
10115 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10116 neglectable and instantiated from within an erroneous instantiation. */
10118 static bool
10120 {
10131 }
10139 /* We're starting to instantiate D; record the template instantiation context
10140 at LOC for diagnostics and to restore it later. */
10142 static bool
10144 {
10148 {
10149 /* Tell error.c not to try to instantiate any templates. */
10152 "template instantiation depth exceeds maximum of %d"
10154 max_tinst_depth);
10156 }
10158 /* If the current instantiation caused problems, don't let it instantiate
10159 anything else. Do allow deduction substitution and decls usable in
10160 constant expressions. */
10164 /* When not -quiet, dump template instantiations other than functions, since
10165 announce_function will take care of those. */
10186 }
10188 /* We're starting substitution of TMPL<ARGS>; record the template
10189 substitution context for diagnostics and to restore it later. */
10191 static bool
10193 {
10195 }
10197 /* We're starting to instantiate D; record INPUT_LOCATION and the
10198 template instantiation context for diagnostics and to restore it
10199 later. */
10201 bool
10203 {
10205 }
10207 /* Likewise, but record LOC as the program location. */
10209 bool
10211 {
10214 }
10216 /* We're done instantiating this template; return to the instantiation
10217 context. */
10219 void
10221 {
10222 /* Restore the filename and line number stashed away when we started
10223 this instantiation. */
10227 }
10229 /* We're instantiating a deferred template; restore the template
10230 instantiation context in which the instantiation was requested, which
10231 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10233 static tree
10235 {
10247 }
10249 /* Returns the TINST_LEVEL which gives the original instantiation
10250 context. */
10254 {
10260 }
10262 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10263 vector of template arguments, as for tsubst.
10265 Returns an appropriate tsubst'd friend declaration. */
10267 static tree
10269 {
10270 tree new_friend;
10275 /* This was a friend declared with an explicit template
10276 argument list, e.g.:
10278 friend void f<>(T);
10280 to indicate that f was a template instantiation, not a new
10281 function declaration. Now, we have to figure out what
10282 instantiation of what template. */
10283 {
10285 tree new_args;
10286 tree tmpl;
10289 /* Friend functions are looked up in the containing namespace scope.
10290 We must enter that scope, to avoid finding member functions of the
10291 current class with same name. */
10306 tsk_none);
10308 }
10312 /* The NEW_FRIEND will look like an instantiation, to the
10313 compiler, but is not an instantiation from the point of view of
10314 the language. For example, we might have had:
10316 template <class T> struct S {
10317 template <class U> friend void f(T, U);
10318 };
10320 Then, in S<int>, template <class U> void f(int, U) is not an
10321 instantiation of anything. */
10327 {
10331 }
10333 /* The mangled name for the NEW_FRIEND is incorrect. The function
10334 is not a template instantiation and should not be mangled like
10335 one. Therefore, we forget the mangling here; we'll recompute it
10336 later if we need it. */
10338 {
10341 }
10344 {
10345 tree old_decl;
10346 tree new_friend_template_info;
10347 tree new_friend_result_template_info;
10348 tree ns;
10351 /* We must save some information from NEW_FRIEND before calling
10352 duplicate decls since that function will free NEW_FRIEND if
10353 possible. */
10355 new_friend_is_defn =
10360 {
10361 /* This declaration is a `primary' template. */
10364 new_friend_result_template_info
10366 }
10367 else
10370 /* Inside pushdecl_namespace_level, we will push into the
10371 current namespace. However, the friend function should go
10372 into the namespace of the template. */
10382 {
10383 /* This new friend declaration matched an existing
10384 declaration. For example, given:
10386 template <class T> void f(T);
10387 template <class U> class C {
10388 template <class T> friend void f(T) {}
10389 };
10391 the friend declaration actually provides the definition
10392 of `f', once C has been instantiated for some type. So,
10393 old_decl will be the out-of-class template declaration,
10394 while new_friend is the in-class definition.
10396 But, if `f' was called before this point, the
10397 instantiation of `f' will have DECL_TI_ARGS corresponding
10398 to `T' but not to `U', references to which might appear
10399 in the definition of `f'. Previously, the most general
10400 template for an instantiation of `f' was the out-of-class
10401 version; now it is the in-class version. Therefore, we
10402 run through all specialization of `f', adding to their
10403 DECL_TI_ARGS appropriately. In particular, they need a
10404 new set of outer arguments, corresponding to the
10405 arguments for this class instantiation.
10407 The same situation can arise with something like this:
10409 friend void f(int);
10410 template <class T> class C {
10411 friend void f(T) {}
10412 };
10414 when `C<int>' is instantiated. Now, `f(int)' is defined
10415 in the class. */
10418 /* On the other hand, if the in-class declaration does
10419 *not* provide a definition, then we don't want to alter
10420 existing definitions. We can just leave everything
10421 alone. */
10422 ;
10423 else
10424 {
10428 /* Overwrite whatever template info was there before, if
10429 any, with the new template information pertaining to
10430 the declaration. */
10434 {
10435 /* We should have called reregister_specialization in
10436 duplicate_decls. */
10441 /* Instantiate it if the global has already been used. */
10445 }
10446 else
10447 {
10448 tree t;
10450 /* Indicate that the old function template is a partial
10451 instantiation. */
10459 /* Reassign any specializations already in the hash table
10460 to the new more general template, and add the
10461 additional template args. */
10465 {
10467 spec_entry elt;
10479 register_specialization
10482 }
10484 }
10485 }
10487 /* The information from NEW_FRIEND has been merged into OLD_DECL
10488 by duplicate_decls. */
10490 }
10491 }
10492 else
10493 {
10497 /* In the code
10498 template <class T> class C {
10499 template <class U> friend void C1<U>::f (); // case 1
10500 friend void C2<T>::f (); // case 2
10501 };
10502 we only need to make sure CONTEXT is a complete type for
10503 case 2. To distinguish between the two cases, we note that
10504 CONTEXT of case 1 remains dependent type after tsubst while
10505 this isn't true for case 2. */
10515 {
10517 /* do_friend adds the TEMPLATE_DECL for any member friend
10518 template even if it isn't a member template, i.e.
10519 template <class T> friend A<T>::f();
10520 Look through it in that case. */
10524 /* Check to see that the declaration is really present, and,
10525 possibly obtain an improved declaration. */
10530 }
10531 }
10534 }
10536 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10537 template arguments, as for tsubst.
10539 Returns an appropriate tsubst'd friend type or error_mark_node on
10540 failure. */
10542 static tree
10544 {
10545 tree tmpl;
10548 {
10551 }
10556 else
10564 {
10565 /* The friend template has already been declared. Just
10566 check to see that the declarations match, and install any new
10567 default parameters. We must tsubst the default parameters,
10568 of course. We only need the innermost template parameters
10569 because that is all that redeclare_class_template will look
10570 at. */
10573 {
10581 }
10582 }
10583 else
10584 {
10585 /* The friend template has not already been declared. In this
10586 case, the instantiation of the template class will cause the
10587 injection of this template into the namespace scope. */
10591 {
10592 /* The new TMPL is not an instantiation of anything, so we
10593 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10594 for the new type because that is supposed to be the
10595 corresponding template decl, i.e., TMPL. */
10602 /* It is hidden. */
10607 /* Inject this template into the enclosing namspace scope. */
10609 }
10610 }
10614 else
10618 }
10620 /* Returns zero if TYPE cannot be completed later due to circularity.
10621 Otherwise returns one. */
10623 static int
10625 {
10635 else
10637 }
10642 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10643 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10645 static tree
10648 {
10657 {
10664 clauses
10668 else
10670 }
10671 /* If the first attribute argument is an identifier, don't
10672 pass it through tsubst. Attributes like mode, format,
10673 cleanup and several target specific attributes expect it
10674 unmodified. */
10676 {
10677 tree chain
10682 }
10684 {
10685 /* An attribute pack expansion. */
10694 {
10698 }
10700 }
10701 else
10708 }
10710 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10711 unchanged or a new TREE_LIST chain. */
10713 static tree
10716 {
10721 {
10725 }
10729 {
10732 {
10735 {
10741 }
10742 }
10744 }
10747 }
10749 /* Apply any attributes which had to be deferred until instantiation
10750 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10751 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10753 static void
10756 {
10758 tree t;
10765 {
10769 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10770 to our attributes parameter. */
10772 }
10773 else
10774 {
10776 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10777 lookup_template_class_1, and should be preserved. */
10781 }
10785 {
10789 }
10793 {
10798 {
10801 {
10807 }
10808 else
10810 }
10813 }
10814 }
10816 /* Perform (or defer) access check for typedefs that were referenced
10817 from within the template TMPL code.
10818 This is a subroutine of instantiate_decl and instantiate_class_template.
10819 TMPL is the template to consider and TARGS is the list of arguments of
10820 that template. */
10822 static void
10824 {
10825 location_t saved_location;
10836 {
10848 /* Make access check error messages point to the location
10849 of the use of the typedef. */
10853 tf_warning_or_error);
10854 }
10856 }
10858 static tree
10860 {
10862 tree typedecl;
10863 tree pbinfo;
10864 tree base_list;
10866 tree fn_context;
10875 /* Figure out which template is being instantiated. */
10879 /* Mark the type as in the process of being defined. */
10882 /* We may be in the middle of deferred access check. Disable
10883 it now. */
10886 /* Determine what specialization of the original template to
10887 instantiate. */
10892 {
10893 /* This TYPE is actually an instantiation of a partial
10894 specialization. We replace the innermost set of ARGS with
10895 the arguments appropriate for substitution. For example,
10896 given:
10898 template <class T> struct S {};
10899 template <class T> struct S<T*> {};
10901 and supposing that we are instantiating S<int*>, ARGS will
10902 presently be {int*} -- but we need {int}. */
10905 }
10906 else
10907 {
10910 }
10912 /* If the template we're instantiating is incomplete, then clearly
10913 there's nothing we can do. */
10915 {
10916 /* We can try again later. */
10919 }
10921 /* If we've recursively instantiated too many templates, stop. */
10929 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10934 else
10935 {
10938 }
10939 /* Use #pragma pack from the template context. */
10945 /* Set the input location to the most specialized template definition.
10946 This is needed if tsubsting causes an error. */
10958 {
10961 /* Adjust visibility for template arguments. */
10963 }
10969 /* We should never instantiate a nested class before its enclosing
10970 class; we need to look up the nested class by name before we can
10971 instantiate it, and that lookup should instantiate the enclosing
10972 class. */
10978 {
10979 tree pbase_binfo;
10980 tree pushed_scope;
10983 /* We must enter the scope containing the type, as that is where
10984 the accessibility of types named in dependent bases are
10985 looked up from. */
10988 /* Substitute into each of the bases to determine the actual
10989 basetypes. */
10991 {
10992 tree base;
10998 {
10999 expanded_bases =
11006 }
11009 {
11011 /* Extract the already-expanded base class. */
11013 else
11014 /* Substitute to figure out the base class. */
11016 NULL_TREE);
11024 }
11025 }
11027 /* The list is now in reverse order; correct that. */
11032 }
11033 /* Now call xref_basetypes to set up all the base-class
11034 information. */
11042 /* Now that our base classes are set up, enter the scope of the
11043 class, so that name lookups into base classes, etc. will work
11044 correctly. This is precisely analogous to what we do in
11045 begin_class_definition when defining an ordinary non-template
11046 class, except we also need to push the enclosing classes. */
11049 /* Now members are processed in the order of declaration. */
11052 {
11056 {
11058 {
11060 /* A closure type for a lambda in an NSDMI or default argument.
11061 Ignore it; it will be regenerated when needed. */
11064 /* Build new CLASSTYPE_NESTED_UTDS. */
11066 tree newtag;
11072 /* If the member is a class template, then -- even after
11073 substitution -- there may be dependent types in the
11074 template argument list for the class. We increment
11075 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11076 that function will assume that no types are dependent
11077 when outside of a template. */
11087 {
11091 /* Unfortunately, lookup_template_class sets
11092 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11093 instantiation (i.e., for the type of a member
11094 template class nested within a template class.)
11095 This behavior is required for
11096 maybe_process_partial_specialization to work
11097 correctly, but is not accurate in this case;
11098 the TAG is not an instantiation of anything.
11099 (The corresponding TEMPLATE_DECL is an
11100 instantiation, but the TYPE is not.) */
11103 /* Now, we call pushtag to put this NEWTAG into the scope of
11104 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11105 pushtag calling push_template_decl. We don't have to do
11106 this for enums because it will already have been done in
11107 tsubst_enum. */
11111 }
11112 }
11114 {
11115 tree r;
11124 /* Instantiate members marked with attribute used. */
11130 }
11133 /* A closure type for a lambda in an NSDMI or default argument.
11135 else
11136 {
11137 /* Build new TYPE_FIELDS. */
11139 {
11140 tree condition;
11143 condition =
11153 }
11155 {
11156 tree r;
11160 /* The file and line for this declaration, to
11161 assist in error message reporting. Since we
11162 called push_tinst_level above, we don't need to
11163 restore these. */
11173 {
11174 /* A capture pack became multiple fields. */
11177 }
11180 {
11184 {
11185 /* In [temp.inst]:
11187 [t]he initialization (and any associated
11188 side-effects) of a static data member does
11189 not occur unless the static data member is
11190 itself used in a way that requires the
11191 definition of the static data member to
11192 exist.
11194 Therefore, we do not substitute into the
11195 initialized for the static data member here. */
11196 finish_static_data_member_decl
11202 /* Instantiate members marked with attribute used. */
11205 }
11207 {
11208 /* Determine whether R has a valid type and can be
11209 completed later. If R is invalid, then its type
11210 is replaced by error_mark_node. */
11216 {
11217 /* If R's type couldn't be completed and
11218 it isn't a flexible array member (whose
11219 type is incomplete by definition) give
11220 an error. */
11223 }
11228 {
11231 }
11232 }
11234 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11235 such a thing will already have been added to the field
11236 list by tsubst_enum in finish_member_declaration in the
11237 CLASSTYPE_NESTED_UTDS case above. */
11241 {
11244 }
11245 }
11246 }
11247 }
11248 }
11249 else
11250 {
11253 {
11254 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11260 {
11261 /* template <class T> friend class C; */
11264 }
11266 {
11267 /* template <class T> friend class C::D; */
11273 }
11276 {
11277 /* This could be either
11279 friend class T::C;
11281 when dependent_type_p is false or
11283 template <class U> friend class T::C;
11285 otherwise. */
11286 /* Bump processing_template_decl in case this is something like
11287 template <class T> friend struct A<T>::B. */
11294 }
11298 {
11299 /* friend class C;
11301 where C hasn't been declared yet. Let's lookup name
11302 from namespace scope directly, bypassing any name that
11303 come from dependent base class. */
11306 /* The call to xref_tag_from_type does injection for friend
11307 classes. */
11309 friend_type =
11313 }
11315 /* friend class C<T>; */
11318 /* Otherwise it's
11320 friend class C;
11322 where C is already declared or
11324 friend class C<int>;
11326 We don't have to do anything in these cases. */
11329 /* Trick make_friend_class into realizing that the friend
11330 we're adding is a template, not an ordinary class. It's
11331 important that we use make_friend_class since it will
11332 perform some error-checking and output cross-reference
11333 information. */
11341 }
11342 else
11343 {
11344 /* Build new DECL_FRIENDLIST. */
11345 tree r;
11347 /* The file and line for this declaration, to
11348 assist in error message reporting. Since we
11349 called push_tinst_level above, we don't need to
11350 restore these. */
11354 {
11357 }
11362 {
11365 }
11366 }
11367 }
11368 }
11371 {
11372 /* Restore these before substituting into the lambda capture
11373 initializers. */
11376 }
11378 /* Set the file and line number information to whatever is given for
11379 the class itself. This puts error messages involving generated
11380 implicit functions at a predictable point, and the same point
11381 that would be used for non-template classes. */
11388 /* We don't instantiate default arguments for member functions. 14.7.1:
11390 The implicit instantiation of a class template specialization causes
11391 the implicit instantiation of the declarations, but not of the
11392 definitions or default arguments, of the class member functions,
11393 member classes, static data members and member templates.... */
11395 /* Some typedefs referenced from within the template code need to be access
11396 checked at template instantiation time, i.e now. These types were
11397 added to the template at parsing time. Let's get those and perform
11398 the access checks then. */
11407 /* The vtable for a template class can be emitted in any translation
11408 unit in which the class is instantiated. When there is no key
11409 method, however, finish_struct_1 will already have added TYPE to
11410 the keyed_classes. */
11415 }
11417 /* Wrapper for instantiate_class_template_1. */
11419 tree
11421 {
11422 tree ret;
11427 }
11429 static tree
11431 {
11432 tree r;
11438 else
11439 {
11446 }
11448 }
11450 /* Given a function parameter pack TMPL_PARM and some function parameters
11451 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11452 and set *SPEC_P to point at the next point in the list. */
11454 tree
11456 {
11457 /* Collect all of the extra "packed" parameters into an
11458 argument pack. */
11459 tree parmvec;
11469 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11473 {
11478 }
11480 /* Build the argument packs. */
11485 }
11487 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11488 NONTYPE_ARGUMENT_PACK. */
11490 static tree
11492 {
11494 }
11496 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11497 pack expansion with no extra args, 2 if it has extra args, or 0
11498 if it is not a pack expansion. */
11500 static int
11502 {
11508 /* A decl pack is itself an expansion. */
11515 }
11518 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11520 static tree
11522 {
11529 }
11531 /* This is a subroutine of tsubst_pack_expansion.
11533 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11534 mechanism to store the (non complete list of) arguments of the
11535 substitution and return a non substituted pack expansion, in order
11536 to wait for when we have enough arguments to really perform the
11537 substitution. */
11539 static bool
11543 {
11544 /* If one pack has an expansion and another pack has a normal
11545 argument or if one pack has an empty argument and an another
11546 one hasn't then tsubst_pack_expansion cannot perform the
11547 substitution and need to fall back on the
11548 PACK_EXPANSION_EXTRA mechanism. */
11556 {
11559 parm_pack;
11561 {
11566 /* We can't substitute a pack expansion with extra args into
11567 our pattern. */
11571 else
11573 }
11577 }
11579 }
11581 /* [temp.variadic]/6 says that:
11583 The instantiation of a pack expansion [...]
11584 produces a list E1,E2, ..., En, where N is the number of elements
11585 in the pack expansion parameters.
11587 This subroutine of tsubst_pack_expansion produces one of these Ei.
11589 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11590 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11591 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11592 INDEX is the index 'i' of the element Ei to produce. ARGS,
11593 COMPLAIN, and IN_DECL are the same parameters as for the
11594 tsubst_pack_expansion function.
11596 The function returns the resulting Ei upon successful completion,
11597 or error_mark_node.
11599 Note that this function possibly modifies the ARGS parameter, so
11600 it's the responsibility of the caller to restore it. */
11602 static tree
11604 tree parm_packs,
11606 tree args /* This parm gets
11608 tsubst_flags_t complain,
11609 tree in_decl)
11610 {
11611 tree t;
11614 /* For each parameter pack, change the substitution of the parameter
11615 pack to the ith argument in its argument pack, then expand the
11616 pattern. */
11618 {
11623 ith_elem_is_expansion |=
11626 /* Select the Ith argument from the pack. */
11630 {
11632 {
11637 }
11638 else
11640 }
11641 else
11642 {
11647 {
11649 /* Update the corresponding argument. */
11651 }
11652 else
11653 /* Re-use the ARGUMENT_PACK_SELECT. */
11655 }
11657 }
11659 /* Substitute into the PATTERN with the (possibly altered)
11660 arguments. */
11662 /* Expanding a fixed parameter pack from
11663 coerce_template_parameter_pack. */
11668 {
11671 else
11674 }
11678 else
11681 /* If the Ith argument pack element is a pack expansion, then
11682 the Ith element resulting from the substituting is going to
11683 be a pack expansion as well. */
11688 }
11690 /* When the unexpanded parameter pack in a fold expression expands to an empty
11691 sequence, the value of the expression is as follows; the program is
11692 ill-formed if the operator is not listed in this table.
11694 && true
11695 || false
11696 , void() */
11698 tree
11700 {
11704 {
11713 }
11719 }
11721 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11722 form an expression that combines the two terms using the
11723 operator of T. */
11725 static tree
11727 {
11731 // Handle compound assignment operators.
11736 {
11746 complain);
11747 }
11748 }
11750 /* Substitute ARGS into the pack of a fold expression T. */
11754 {
11756 }
11758 /* Substitute ARGS into the pack of a fold expression T. */
11762 {
11764 }
11766 /* Expand a PACK of arguments into a grouped as left fold.
11767 Given a pack containing elements A0, A1, ..., An and an
11768 operator @, this builds the expression:
11770 ((A0 @ A1) @ A2) ... @ An
11772 Note that PACK must not be empty.
11774 The operator is defined by the original fold expression T. */
11776 static tree
11778 {
11781 {
11784 }
11786 }
11788 /* Substitute into a unary left fold expression. */
11790 static tree
11792 tree in_decl)
11793 {
11798 {
11802 }
11805 else
11807 }
11809 /* Substitute into a binary left fold expression.
11811 Do ths by building a single (non-empty) vector of argumnts and
11812 building the expression from those elements. */
11814 static tree
11816 tree in_decl)
11817 {
11826 {
11831 }
11839 }
11841 /* Expand a PACK of arguments into a grouped as right fold.
11842 Given a pack containing elementns A0, A1, ..., and an
11843 operator @, this builds the expression:
11845 A0@ ... (An-2 @ (An-1 @ An))
11847 Note that PACK must not be empty.
11849 The operator is defined by the original fold expression T. */
11851 tree
11853 {
11854 // Build the expression.
11858 {
11861 }
11863 }
11865 /* Substitute into a unary right fold expression. */
11867 static tree
11869 tree in_decl)
11870 {
11875 {
11879 }
11882 else
11884 }
11886 /* Substitute into a binary right fold expression.
11888 Do ths by building a single (non-empty) vector of arguments and
11889 building the expression from those elements. */
11891 static tree
11893 tree in_decl)
11894 {
11903 {
11908 }
11917 }
11919 /* Walk through the pattern of a pack expansion, adding everything in
11920 local_specializations to a list. */
11922 struct el_data
11923 {
11925 tree extra;
11926 tsubst_flags_t complain;
11930 };
11931 static tree
11933 {
11939 /* Remember local typedefs (85214). */
11945 {
11947 /* Don't mess with variables declared within the pattern. */
11950 {
11951 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11954 {
11960 }
11962 {
11963 /* Handle lambda capture here, since we aren't doing any
11964 substitution now, and so tsubst_copy won't call
11965 process_outer_var_ref. */
11969 {
11975 {
11976 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11977 proxies. */
11979 {
11984 }
11986 }
11987 }
11988 }
11989 }
11993 }
11995 }
11996 static tree
11998 {
12002 }
12004 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
12005 for use in PACK_EXPANSION_EXTRA_ARGS. */
12007 tree
12009 {
12015 }
12017 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12018 normal template args to ARGS. */
12020 tree
12022 {
12024 {
12026 {
12027 /* The partial instantiation involved local declarations collected in
12028 extract_local_specs; map from the general template to our local
12029 context. */
12035 /* else inst is already a full instantiation of the pack. */
12037 }
12040 }
12042 }
12044 /* Substitute ARGS into T, which is an pack expansion
12045 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12046 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12047 (if only a partial substitution could be performed) or
12048 ERROR_MARK_NODE if there was an error. */
12049 tree
12051 tree in_decl)
12052 {
12053 tree pattern;
12058 tree result;
12066 /* Add in any args remembered from an earlier partial instantiation. */
12071 /* Determine the argument packs that will instantiate the parameter
12072 packs used in the expansion expression. While we're at it,
12073 compute the number of arguments to be expanded and make sure it
12074 is consistent. */
12077 {
12084 {
12090 complain);
12091 else
12095 }
12097 {
12099 {
12102 parm_pack);
12104 }
12107 }
12109 {
12110 /* We know we have correct local_specializations if this
12111 expansion is at function scope, or if we're dealing with a
12112 local parameter in a requires expression; for the latter,
12113 tsubst_requires_expr set it up appropriately. */
12116 else
12117 /* We can't rely on local_specializations for a parameter
12118 name used later in a function declaration (such as in a
12119 late-specified return type). Even if it exists, it might
12120 have the wrong value for a recursive call. */
12124 {
12125 /* This parameter pack was used in an unevaluated context. Just
12126 make a dummy decl, since it's only used for its type. */
12131 /* Partial instantiation of the parm_pack, we can't build
12132 up an argument pack yet. */
12134 else
12136 }
12138 /* This argument pack isn't fully instantiated yet. We set this
12139 flag rather than clear arg_pack because we do want to do the
12140 optimization below, and we don't want to substitute directly
12141 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12142 where it isn't expected). */
12144 }
12146 {
12150 }
12151 else
12152 {
12158 }
12165 /* This can only happen if we forget to expand an argument
12166 pack somewhere else. Just return an error, silently. */
12167 {
12171 }
12174 {
12178 /* Don't bother trying to do a partial substitution with
12179 incomplete packs; we'll try again after deduction. */
12187 {
12192 pattern);
12193 else
12195 pattern);
12197 }
12199 /* Keep track of the parameter packs and their corresponding
12200 argument packs. */
12203 }
12204 else
12205 {
12206 /* We can't substitute for this parameter pack. We use a flag as
12207 well as the missing_level counter because function parameter
12208 packs don't have a level. */
12211 }
12212 }
12214 /* If the expansion is just T..., return the matching argument pack, unless
12215 we need to call convert_from_reference on all the elements. This is an
12216 important optimization; see c++/68422. */
12219 {
12222 /* If the argument pack is a single pack expansion, pull it out. */
12227 /* Types need no adjustment, nor does sizeof..., and if we still have
12228 some pack expansion args we won't do anything yet. */
12233 /* Also optimize expression pack expansions if we can tell that the
12234 elements won't have reference type. */
12240 /* Otherwise use the normal path so we get convert_from_reference. */
12241 }
12243 /* We cannot expand this expansion expression, because we don't have
12244 all of the argument packs we need. */
12246 {
12247 /* We got some full packs, but we can't substitute them in until we
12248 have values for all the packs. So remember these until then. */
12254 }
12256 {
12257 /* There were no real arguments, we're just replacing a parameter
12258 pack with another version of itself. Substitute into the
12259 pattern and return a PACK_EXPANSION_*. The caller will need to
12260 deal with that. */
12264 else
12268 }
12273 {
12274 /* We're in a late-specified return type, so create our own local
12275 specializations map; the current map is either NULL or (in the
12276 case of recursive unification) might have bindings that we don't
12277 want to use or alter. */
12280 }
12282 /* For each argument in each argument pack, substitute into the
12283 pattern. */
12287 {
12289 i,
12291 in_decl);
12294 {
12297 }
12298 }
12300 /* Update ARGS to restore the substitution from parameter packs to
12301 their argument packs. */
12303 {
12310 else
12311 {
12319 /* Update the corresponding argument. */
12323 else
12325 }
12326 }
12329 {
12332 }
12334 /* If the dependent pack arguments were such that we end up with only a
12335 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12341 }
12343 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12344 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12345 parameter packs; all parms generated from a function parameter pack will
12346 have the same DECL_PARM_INDEX. */
12348 tree
12350 {
12352 tree patparm;
12355 {
12361 }
12362 else
12363 {
12368 }
12371 }
12373 /* Make an argument pack out of the TREE_VEC VEC. */
12375 static tree
12377 {
12378 tree pack;
12382 else
12383 {
12386 }
12389 }
12391 /* Return an exact copy of template args T that can be modified
12392 independently. */
12394 static tree
12396 {
12404 {
12409 }
12415 }
12417 /* Substitute ARGS into the vector or list of template arguments T. */
12419 static tree
12421 {
12433 {
12435 tree new_arg;
12440 {
12441 /* Substitute into an expansion expression. */
12445 /* Add to the expanded length adjustment the number of
12446 expanded arguments. We subtract one from this
12447 measurement, because the argument pack expression
12448 itself is already counted as 1 in
12449 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12450 the argument pack is empty. */
12452 }
12454 {
12455 /* Substitute into each of the arguments. */
12464 else
12469 }
12470 else
12479 }
12484 /* Make space for the expanded arguments coming from template
12485 argument packs. */
12487 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12488 arguments for a member template.
12489 In that case each TREE_VEC in ORIG_T represents a level of template
12490 arguments, and ORIG_T won't carry any non defaulted argument count.
12491 It will rather be the nested TREE_VECs that will carry one.
12492 In other words, ORIG_T carries a non defaulted argument count only
12493 if it doesn't contain any nested TREE_VEC. */
12495 {
12499 }
12501 {
12505 {
12508 /* Now expand the template argument pack "in place". */
12511 }
12512 else
12513 {
12515 out++;
12516 }
12517 }
12520 }
12522 /* Substitute ARGS into one level PARMS of template parameters. */
12524 static tree
12526 {
12533 {
12541 }
12544 }
12546 /* Return the result of substituting ARGS into the template parameters
12547 given by PARMS. If there are m levels of ARGS and m + n levels of
12548 PARMS, then the result will contain n levels of PARMS. For
12549 example, if PARMS is `template <class T> template <class U>
12550 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12551 result will be `template <int*, double, class V>'. */
12553 static tree
12555 {
12559 /* When substituting into a template, we must set
12560 PROCESSING_TEMPLATE_DECL as the template parameters may be
12561 dependent if they are based on one-another, and the dependency
12562 predicates are short-circuit outside of templates. */
12569 {
12576 }
12581 }
12583 /* Return the result of substituting ARGS into one template parameter
12584 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12585 parameter and which TREE_PURPOSE is the default argument of the
12586 template parameter. */
12588 static tree
12590 {
12611 }
12613 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12614 type T. If T is not an aggregate or enumeration type, it is
12615 handled as if by tsubst. IN_DECL is as for tsubst. If
12616 ENTERING_SCOPE is nonzero, T is the context for a template which
12617 we are presently tsubst'ing. Return the substituted value. */
12619 static tree
12621 tree args,
12622 tsubst_flags_t complain,
12623 tree in_decl,
12625 {
12630 {
12635 /* Fall through. */
12639 {
12640 tree argvec;
12641 tree context;
12642 tree r;
12646 /* In "sizeof(X<I>)" we need to evaluate "I". */
12652 /* First, determine the context for the type we are looking
12653 up. */
12656 {
12659 /* If context is a nested class inside a class template,
12660 it may still need to be instantiated (c++/33959). */
12662 }
12664 /* Then, figure out what arguments are appropriate for the
12665 type we are trying to find. For example, given:
12667 template <class T> struct S;
12668 template <class T, class U> void f(T, U) { S<U> su; }
12670 and supposing that we are instantiating f<int, double>,
12671 then our ARGS will be {int, double}, but, when looking up
12672 S we only want {double}. */
12677 else
12678 {
12682 }
12688 }
12689 else
12690 /* This is not a template type, so there's nothing to do. */
12695 }
12696 }
12700 /* Substitute into the default argument ARG (a default argument for
12701 FN), which has the indicated TYPE. */
12703 tree
12705 tsubst_flags_t complain)
12706 {
12709 /* This can happen in invalid code. */
12727 /* This default argument came from a template. Instantiate the
12728 default argument here, not in tsubst. In the case of
12729 something like:
12731 template <class T>
12732 struct S {
12733 static T t();
12734 void f(T = t());
12735 };
12737 we must be careful to do name lookup in the scope of S<T>,
12738 rather than in the current class. */
12743 /* The default argument expression may cause implicitly defined
12744 member functions to be synthesized, which will result in garbage
12745 collection. We must treat this situation as if we were within
12746 the body of function so as to avoid collecting live data on the
12747 stack. */
12761 /* Make sure the default argument is reasonable. */
12768 {
12772 }
12775 }
12777 /* Substitute into all the default arguments for FN. */
12779 static void
12781 {
12782 tree arg;
12783 tree tmpl_args;
12787 /* If this function is not yet instantiated, we certainly don't need
12788 its default arguments. */
12791 /* Don't do this again for clones. */
12797 arg;
12803 complain);
12804 }
12806 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12808 static tree
12810 tree lambda_fntype)
12811 {
12816 /* Nobody should be tsubst'ing into non-template functions. */
12820 {
12821 /* If T is not dependent, just return it. */
12825 /* Calculate the most general template of which R is a
12826 specialization. */
12829 /* We're substituting a lambda function under tsubst_lambda_expr but not
12830 directly from it; find the matching function we're already inside.
12831 But don't do this if T is a generic lambda with a single level of
12832 template parms, as in that case we're doing a normal instantiation. */
12838 /* Calculate the complete set of arguments used to
12839 specialize R. */
12841 (DECL_TEMPLATE_RESULT
12847 /* Check to see if we already have this specialization. */
12849 {
12853 }
12855 /* We can see more levels of arguments than parameters if
12856 there was a specialization of a member template, like
12857 this:
12859 template <class T> struct S { template <class U> void f(); }
12860 template <> template <class U> void S<int>::f(U);
12862 Here, we'll be substituting into the specialization,
12863 because that's where we can find the code we actually
12864 want to generate, but we'll have enough arguments for
12865 the most general template.
12867 We also deal with the peculiar case:
12869 template <class T> struct S {
12870 template <class U> friend void f();
12871 };
12872 template <class U> void f() {}
12873 template S<int>;
12874 template void f<double>();
12876 Here, the ARGS for the instantiation of will be {int,
12877 double}. But, we only need as many ARGS as there are
12878 levels of template parameters in CODE_PATTERN. We are
12879 careful not to get fooled into reducing the ARGS in
12880 situations like:
12882 template <class T> struct S { template <class U> void f(U); }
12883 template <class T> template <> void S<T>::f(int) {}
12885 which we can spot because the pattern will be a
12886 specialization in this case. */
12893 }
12894 else
12895 {
12896 /* This special case arises when we have something like this:
12898 template <class T> struct S {
12899 friend void f<int>(int, double);
12900 };
12902 Here, the DECL_TI_TEMPLATE for the friend declaration
12903 will be an IDENTIFIER_NODE. We are being called from
12904 tsubst_friend_function, and we want only to create a
12905 new decl (R) with appropriate types so that we can call
12906 determine_specialization. */
12909 }
12926 /* If we hit excessive deduction depth, the type is bogus even if
12927 it isn't error_mark_node, so don't build a decl. */
12931 /* We do NOT check for matching decls pushed separately at this
12932 point, as they may not represent instantiations of this
12933 template, and in any case are considered separate under the
12934 discrete model. */
12938 /* Clear out the mangled name and RTL for the instantiation. */
12941 /* Leave DECL_INITIAL set on deleted instantiations. */
12946 /* OpenMP UDRs have the only argument a reference to the declared
12947 type. We want to diagnose if the declared type is a reference,
12948 which is invalid, but as references to references are usually
12949 quietly merged, diagnose it here. */
12951 {
12952 tree argtype
12957 "reference type %qT in "
12961 argtype);
12962 }
12965 /* Type-conversion operator. Reconstruct the name, in
12966 case it's the name of one of the template's parameters. */
12976 {
12980 }
12987 /* If this is an instantiation of a function with internal
12988 linkage, we already know what object file linkage will be
12989 assigned to the instantiation. */
12998 /* We'll re-clone as appropriate in instantiate_template. */
13001 /* If we aren't complaining now, return on error before we register
13002 the specialization so that we'll complain eventually. */
13008 /* When instantiating a constrained member, substitute
13009 into the constraints to create a new constraint. */
13012 {
13015 }
13017 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13018 this in the special friend case mentioned above where
13019 GEN_TMPL is NULL. */
13021 {
13026 tree new_r
13029 /* We instantiated this while substituting into
13030 the type earlier (template/friend54.C). */
13033 /* We're not supposed to instantiate default arguments
13034 until they are called, for a template. But, for a
13035 declaration like:
13037 template <class T> void f ()
13038 { extern void g(int i = T()); }
13040 we should do the substitution when the template is
13041 instantiated. We handle the member function case in
13042 instantiate_class_template since the default arguments
13043 might refer to other members of the class. */
13048 }
13049 else
13052 /* Copy the list of befriending classes. */
13056 {
13060 }
13063 {
13067 /* If this is an instantiation of a member template, clone it.
13068 If it isn't, that'll be handled by
13069 clone_constructors_and_destructors. */
13072 }
13083 /* Possibly limit visibility based on template args. */
13086 {
13090 }
13099 }
13101 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13103 static tree
13105 tree lambda_fntype)
13106 {
13107 /* We can get here when processing a member function template,
13108 member class template, or template template parameter. */
13111 tree spec;
13112 tree tmpl_args;
13113 tree full_args;
13114 tree r;
13118 {
13119 /* Template template parameter is treated here. */
13123 /* If we get a real template back, return it. This can happen in
13124 the context of most_specialized_partial_spec. */
13127 else
13128 /* The new TEMPLATE_DECL was built in
13129 reduce_template_parm_level. */
13132 }
13135 {
13136 /* We might already have an instance of this template.
13137 The ARGS are for the surrounding class type, so the
13138 full args contain the tsubst'd args for the context,
13139 plus the innermost args from the template decl. */
13143 /* Because this is a template, the arguments will still be
13144 dependent, even after substitution. If
13145 PROCESSING_TEMPLATE_DECL is not set, the dependency
13146 predicates will short-circuit. */
13154 /* If this is a default template template argument,
13155 tsubst might not have changed anything. */
13163 }
13165 /* Make a new template decl. It will be similar to the
13166 original, but will record the current template arguments.
13167 We also create a new function declaration, which is just
13168 like the old one, but points to this new template, rather
13169 than the old one. */
13174 // Build new template info linking to the original template decl.
13176 {
13179 }
13180 else
13183 /* The template parameters for this new template are all the
13184 template parameters for the old template, except the
13185 outermost level of parameters. */
13188 complain);
13192 {
13193 tree new_type;
13201 /* For a partial specialization, we need to keep pointing to
13202 the primary template. */
13208 }
13209 else
13210 {
13211 tree new_decl;
13215 else
13225 {
13228 }
13229 else
13230 {
13233 }
13234 }
13244 /* Record this non-type partial instantiation. */
13250 }
13252 /* True if FN is the op() for a lambda in an uninstantiated template. */
13254 bool
13256 {
13261 }
13263 /* We're instantiating a variable from template function TCTX. Return the
13264 corresponding current enclosing scope. This gets complicated because lambda
13265 functions in templates are regenerated rather than instantiated, but generic
13266 lambda functions are subsequently instantiated. */
13268 static tree
13270 {
13279 {
13292 }
13294 }
13296 /* Substitute the ARGS into the T, which is a _DECL. Return the
13297 result of the substitution. Issue error and warning messages under
13298 control of COMPLAIN. */
13300 static tree
13302 {
13303 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13304 location_t saved_loc;
13309 /* Set the filename and linenumber to improve error-reporting. */
13314 {
13324 {
13332 {
13333 /* If there is a local specialization that isn't a
13334 parameter pack, it means that we're doing a "simple"
13335 substitution from inside tsubst_pack_expansion. Just
13336 return the local specialization (which will be a single
13337 parm). */
13344 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13345 the parameters in this function parameter pack. */
13349 {
13352 /* Zero-length parameter packs are boring. Just substitute
13353 into the chain. */
13357 }
13358 else
13359 {
13360 /* All we did was update the type. Make a note of that. */
13363 }
13364 }
13366 /* Loop through all of the parameters we'll build. When T is
13367 a function parameter pack, LEN is the number of expanded
13368 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13371 {
13378 /* We're on the Ith parameter of the function parameter
13379 pack. */
13380 {
13381 /* Get the Ith type. */
13384 /* Rename the parameter to include the index. */
13387 }
13389 /* We're dealing with a normal parameter. */
13397 {
13400 else
13403 }
13413 /* Keep track of the first new parameter we
13414 generate. That's what will be returned to the
13415 caller. */
13419 /* Build a proper chain of parameters when substituting
13420 into a function parameter pack. */
13423 }
13425 /* If cp_unevaluated_operand is set, we're just looking for a
13426 single dummy parameter, so don't keep going. */
13431 /* FIRST_R contains the start of the chain we've built. */
13433 }
13437 {
13444 {
13445 /* This field is a lambda capture pack. Return a TREE_VEC of
13446 the expanded fields to instantiate_class_template_1. */
13450 {
13453 }
13454 else
13455 {
13456 /* All we did was update the type. Make a note of that. */
13459 }
13460 }
13463 {
13466 {
13470 }
13480 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13481 number of bits. */
13487 {
13488 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13489 NSDMI in perform_member_init. Still set DECL_INITIAL
13490 so that we know there is one. */
13495 }
13496 /* We don't have to set DECL_CONTEXT here; it is set by
13497 finish_member_declaration. */
13505 }
13509 }
13513 /* We reach here only for member using decls. We also need to check
13514 uses_template_parms because DECL_DEPENDENT_P is not set for a
13515 using-declaration that designates a member of the current
13516 instantiation (c++/53549). */
13519 {
13523 {
13528 {
13532 {
13535 }
13536 else
13537 {
13540 }
13542 }
13543 }
13544 else
13545 {
13551 else
13552 {
13555 }
13556 }
13557 }
13558 else
13559 {
13562 }
13567 {
13570 tree spec;
13572 tree ctx;
13581 {
13582 /* If this is the canonical decl, we don't have to
13583 mess with instantiations, and often we can't (for
13584 typename, template type parms and such). Note that
13585 TYPE_NAME is not correct for the above test if
13586 we've copied the type for a typedef. */
13592 }
13594 /* Check to see if we already have the specialization we
13595 need. */
13598 {
13599 /* T is a static data member or namespace-scope entity.
13600 We have to substitute into namespace-scope variables
13601 (not just variable templates) because of cases like:
13603 template <class T> void f() { extern T t; }
13605 where the entity referenced is not known until
13606 instantiation time. */
13610 {
13612 complain,
13614 /* If CTX is unchanged, then T is in fact the
13615 specialization we want. That situation occurs when
13616 referencing a static data member within in its own
13617 class. We can use pointer equality, rather than
13618 same_type_p, because DECL_CONTEXT is always
13619 canonical... */
13621 /* ... unless T is a member template; in which
13622 case our caller can be willing to create a
13623 specialization of that template represented
13624 by T. */
13628 }
13631 {
13636 argvec = (coerce_innermost_template_parms
13644 }
13645 }
13646 else
13647 {
13648 /* A local variable. */
13650 /* Subsequent calls to pushdecl will fill this in. */
13652 /* Unless this is a reference to a static variable from an
13653 enclosing function, in which case we need to fill it in now. */
13655 {
13659 }
13661 }
13662 /* If we already have the specialization we need, there is
13663 nothing more to do. */
13665 {
13668 }
13670 /* Create a new node for the specialization we need. */
13672 {
13675 else
13683 {
13684 /* Mask off any template args past the variable's context so we
13685 don't replace the auto with an unrelated argument. */
13689 /* This should never happen with the new lambda instantiation
13690 model, but keep the handling just in case. */
13693 }
13695 /* Substituting the type might have recursively instantiated this
13696 same alias (c++/86171). */
13699 {
13702 }
13703 }
13706 {
13712 {
13713 /* It may seem that this case cannot occur, since:
13715 typedef void f();
13716 void g() { f x; }
13718 declares a function, not a variable. However:
13720 typedef void f();
13721 template <typename T> void g() { T t; }
13722 template void g<f>();
13724 is an attempt to declare a variable with function
13725 type. */
13727 /* R is not yet sufficiently initialized, so we
13728 just use its name. */
13731 }
13733 /* Wait until cp_finish_decl to set this again, to handle
13734 circular dependency (template/instantiate6.C). */
13739 {
13744 {
13747 }
13749 }
13753 }
13759 /* Clear out the mangled name and RTL for the instantiation. */
13763 /* The initializer must not be expanded until it is required;
13764 see [temp.inst]. */
13768 {
13774 /* Possibly limit visibility based on template args. */
13777 {
13781 }
13783 }
13786 {
13787 /* A static data member declaration is always marked
13788 external when it is declared in-class, even if an
13789 initializer is present. We mimic the non-template
13790 processing here. */
13798 }
13799 else
13800 {
13805 }
13813 /* Preserve a typedef that names a type. */
13815 {
13819 /* An alias template specialization can be dependent
13820 even if its underlying type is not. */
13822 }
13825 }
13830 }
13831 #undef RETURN
13833 out:
13834 /* Restore the file and line information. */
13838 }
13840 /* Substitute into the ARG_TYPES of a function type.
13841 If END is a TREE_CHAIN, leave it and any following types
13842 un-substituted. */
13844 static tree
13846 tree args,
13847 tree end,
13848 tsubst_flags_t complain,
13849 tree in_decl)
13850 {
13851 tree remaining_arg_types;
13855 tree default_arg;
13866 {
13867 /* For a pack expansion, perform substitution on the
13868 entire expression. Later on, we'll handle the arguments
13869 one-by-one. */
13874 /* So that we'll spin through the parameters, one by one. */
13876 else
13877 {
13878 /* We only partially substituted into the parameter
13879 pack. Our type is TYPE_PACK_EXPANSION. */
13882 }
13883 }
13896 {
13898 {
13902 }
13904 }
13905 /* DR 657. */
13909 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13910 top-level qualifiers as required. */
13913 /* We do not substitute into default arguments here. The standard
13914 mandates that they be instantiated only when needed, which is
13915 done in build_over_call. */
13918 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13919 since the new op() won't have any associated template arguments for us
13920 to refer to later. */
13926 {
13927 /* We've instantiated a template before its default arguments
13928 have been parsed. This can happen for a nested template
13929 class, and is not an error unless we require the default
13930 argument in a call of this function. */
13931 remaining_arg_types =
13934 }
13935 else
13936 remaining_arg_types =
13938 }
13941 }
13943 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13944 *not* handle the exception-specification for FNTYPE, because the
13945 initial substitution of explicitly provided template parameters
13946 during argument deduction forbids substitution into the
13947 exception-specification:
13949 [temp.deduct]
13951 All references in the function type of the function template to the
13952 corresponding template parameters are replaced by the specified tem-
13953 plate argument values. If a substitution in a template parameter or
13954 in the function type of the function template results in an invalid
13955 type, type deduction fails. [Note: The equivalent substitution in
13956 exception specifications is done only when the function is instanti-
13957 ated, at which point a program is ill-formed if the substitution
13958 results in an invalid type.] */
13960 static tree
13962 tree args,
13963 tsubst_flags_t complain,
13964 tree in_decl)
13965 {
13966 tree return_type;
13968 tree fntype;
13970 /* The TYPE_CONTEXT is not used for function/method types. */
13973 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13974 failure. */
13978 {
13979 /* Substitute the argument types. */
13991 {
13992 /* DR 1207: 'this' is in scope in the trailing return type. */
13994 }
13996 /* Substitute the return type. */
14000 {
14003 }
14004 }
14005 else
14006 /* Substitute the return type. */
14011 /* DR 486 clarifies that creation of a function type with an
14012 invalid return type is a deduction failure. */
14015 {
14017 {
14020 else
14022 }
14024 }
14025 /* And DR 657. */
14030 {
14031 /* Substitute the argument types. */
14036 }
14038 /* Construct a new type node and return it. */
14040 {
14043 }
14044 else
14045 {
14047 /* Don't pick up extra function qualifiers from the basetype. */
14050 {
14051 /* [temp.deduct]
14053 Type deduction may fail for any of the following
14054 reasons:
14056 -- Attempting to create "pointer to member of T" when T
14057 is not a class type. */
14060 r);
14062 }
14066 }
14069 /* See comment above. */
14075 }
14077 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14078 ARGS into that specification, and return the substituted
14079 specification. If there is no specification, return NULL_TREE. */
14081 static tree
14083 tree args,
14084 tsubst_flags_t complain,
14085 tree in_decl,
14087 {
14088 tree specs;
14089 tree new_specs;
14094 {
14095 /* A noexcept-specifier. */
14100 {
14101 /* Defer instantiation of noexcept-specifiers to avoid
14102 excessive instantiations (c++/49107). */
14105 {
14106 /* We already partially instantiated this member template,
14107 so combine the new args with the old. */
14112 }
14113 else
14114 {
14117 }
14118 }
14119 else
14120 new_specs = tsubst_copy_and_build
14124 }
14126 {
14129 else
14131 {
14132 tree spec;
14137 {
14138 /* Expand the pack expansion type. */
14141 in_decl);
14147 else
14148 {
14149 /* We're substituting into a member template, so
14150 we got a TYPE_PACK_EXPANSION back. Add that
14151 expansion and move on. */
14155 expanded_specs,
14156 complain);
14159 }
14160 }
14163 {
14166 else
14171 complain);
14172 }
14175 }
14176 }
14178 }
14180 /* Take the tree structure T and replace template parameters used
14181 therein with the argument vector ARGS. IN_DECL is an associated
14182 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14183 Issue error and warning messages under control of COMPLAIN. Note
14184 that we must be relatively non-tolerant of extensions here, in
14185 order to preserve conformance; if we allow substitutions that
14186 should not be allowed, we may allow argument deductions that should
14187 not succeed, and therefore report ambiguous overload situations
14188 where there are none. In theory, we could allow the substitution,
14189 but indicate that it should have failed, and allow our caller to
14190 make sure that the right thing happens, but we don't try to do this
14191 yet.
14193 This function is used for dealing with types, decls and the like;
14194 for expressions, use tsubst_expr or tsubst_copy. */
14196 tree
14198 {
14221 else
14226 /* Reuse typedefs. We need to do this to handle dependent attributes,
14227 such as attribute aligned. */
14230 {
14234 {
14235 /* DECL represents an alias template and we want to
14236 instantiate it. */
14240 }
14244 {
14248 }
14253 else
14254 /* The typedef is from a non-template context. */
14258 {
14260 r = cp_build_qualified_type_real
14264 }
14265 else
14266 {
14267 /* We don't have an instantiation yet, so drop the typedef. */
14272 }
14273 }
14290 {
14316 {
14322 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14323 needed. */
14329 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14330 with TREE_SIDE_EFFECTS that indicates this is not an integral
14331 constant expression. */
14334 {
14337 }
14340 }
14346 {
14352 /* Early in template argument deduction substitution, we don't
14353 want to reduce the level of 'auto', or it will be confused
14354 with a normal template parm in subsequent deduction. */
14366 {
14369 /* See through ARGUMENT_PACK_SELECT arguments. */
14372 }
14377 {
14379 /* If ARG is an argument pack, we don't actually want to
14380 perform a substitution here, because substitutions
14381 for argument packs are only done
14382 element-by-element. We can get to this point when
14383 substituting the type of a non-type template
14384 parameter pack, when that type actually contains
14385 template parameter packs from an outer template, e.g.,
14387 template<typename... Types> struct A {
14388 template<Types... Values> struct B { };
14389 }; */
14393 {
14399 return cp_build_qualified_type_real
14401 }
14403 {
14404 /* We are processing a type constructed from a
14405 template template parameter. */
14416 /* Consider this code:
14418 template <template <class> class Template>
14419 struct Internal {
14420 template <class Arg> using Bind = Template<Arg>;
14421 };
14423 template <template <class> class Template, class Arg>
14424 using Instantiate = Template<Arg>; //#0
14426 template <template <class> class Template,
14427 class Argument>
14428 using Bind =
14429 Instantiate<Internal<Template>::template Bind,
14430 Argument>; //#1
14432 When #1 is parsed, the
14433 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14434 parameter `Template' in #0 matches the
14435 UNBOUND_CLASS_TEMPLATE representing the argument
14436 `Internal<Template>::template Bind'; We then want
14437 to assemble the type `Bind<Argument>' that can't
14438 be fully created right now, because
14439 `Internal<Template>' not being complete, the Bind
14440 template cannot be looked up in that context. So
14441 we need to "store" `Bind<Argument>' for later
14442 when the context of Bind becomes complete. Let's
14443 store that in a TYPENAME_TYPE. */
14447 argvec),
14448 typename_type,
14449 complain);
14451 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14452 are resolving nested-types in the signature of a
14453 member function templates. Otherwise ARG is a
14454 TEMPLATE_DECL and is the real template to be
14455 instantiated. */
14463 complain);
14464 return cp_build_qualified_type_real
14466 }
14469 else
14470 /* TEMPLATE_PARM_INDEX. */
14472 }
14475 /* This can happen during the attempted tsubst'ing in
14476 unify. This means that we don't yet have any information
14477 about the template parameter in question. */
14480 /* If we get here, we must have been looking at a parm for a
14481 more deeply nested template. Make a new version of this
14482 template parameter, but with a lower level. */
14484 {
14489 {
14491 r = cp_build_qualified_type_real
14495 }
14502 /* Break infinite recursion when substituting the constraints
14511 /* Cache the simple case of lowering a type parameter. */
14513 else
14514 {
14525 {
14526 /* Propagate constraints on placeholders. */
14531 {
14534 }
14535 }
14538 /* We have reduced the level of the template
14539 template parameter, but not the levels of its
14540 template parameters, so canonical_type_parameter
14541 will not be able to find the canonical template
14542 template parameter for this level. Thus, we
14543 require structural equality checking to compare
14544 TEMPLATE_TEMPLATE_PARMs. */
14548 else
14552 {
14554 /* We might need to substitute into the types of non-type
14555 template parameters. */
14567 }
14568 }
14572 /* OK, now substitute the type of the non-type parameter. We
14573 couldn't do it earlier because it might be an auto parameter,
14574 and we wouldn't need to if we had an argument. */
14583 }
14586 }
14589 {
14597 {
14601 }
14604 {
14608 }
14611 {
14615 }
14621 }
14624 /* We should never be tsubsting a binfo. */
14628 /* A vector of template arguments. */
14634 {
14638 /* [temp.deduct]
14640 Type deduction may fail for any of the following
14641 reasons:
14643 -- Attempting to create a pointer to reference type.
14644 -- Attempting to create a reference to a reference type or
14645 a reference to void.
14647 Core issue 106 says that creating a reference to a reference
14648 during instantiation is no longer a cause for failure. We
14649 only enforce this check in strict C++98 mode. */
14653 {
14656 /* We keep track of the last time we issued this error
14657 message to avoid spewing a ton of messages during a
14658 single bad template instantiation. */
14661 {
14666 else
14669 }
14672 }
14676 {
14678 {
14681 type);
14682 else
14684 type);
14685 }
14687 }
14689 {
14693 }
14695 /* In C++0x, during template argument substitution, when there is an
14696 attempt to create a reference to a reference type, reference
14697 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14699 "If a template-argument for a template-parameter T names a type
14700 that is a reference to a type A, an attempt to create the type
14701 'lvalue reference to cv T' creates the type 'lvalue reference to
14702 A,' while an attempt to create the type type rvalue reference to
14703 cv T' creates the type T"
14704 */
14705 r = cp_build_reference_type
14708 else
14713 /* Will this ever be needed for TYPE_..._TO values? */
14717 }
14719 {
14722 {
14723 /* [temp.deduct]
14725 Type deduction may fail for any of the following
14726 reasons:
14728 -- Attempting to create "pointer to member of T" when T
14729 is not a class type. */
14733 }
14735 {
14739 }
14741 {
14745 }
14748 {
14749 /* The type of the implicit object parameter gets its
14750 cv-qualifiers from the FUNCTION_TYPE. */
14751 tree memptr;
14752 tree method_type
14757 complain);
14758 }
14759 else
14762 complain);
14763 }
14766 {
14767 tree fntype;
14768 tree specs;
14773 /* Substitute the exception specification. */
14781 }
14783 {
14788 /* As an optimization, we avoid regenerating the array type if
14789 it will obviously be the same as T. */
14793 /* These checks should match the ones in create_array_type_for_decl.
14795 [temp.deduct]
14797 The deduction may fail for any of the following reasons:
14799 -- Attempting to create an array with an element type that
14800 is void, a function type, or a reference type, or [DR337]
14801 an abstract class type. */
14807 {
14811 }
14823 {
14826 }
14829 }
14832 {
14844 {
14848 }
14850 {
14851 /* Normally, make_typename_type does not require that the CTX
14852 have complete type in order to allow things like:
14854 template <class T> struct S { typename S<T>::X Y; };
14856 But, such constructs have already been resolved by this
14857 point, so here CTX really should have complete type, unless
14858 it's a partial instantiation. */
14861 {
14865 }
14866 }
14873 {
14876 }
14879 {
14881 {
14885 else
14887 }
14889 {
14893 else
14895 }
14896 }
14898 return cp_build_qualified_type_real
14900 }
14903 {
14915 }
14918 {
14919 tree type;
14935 complain);
14936 }
14939 {
14940 tree type;
14951 {
14953 {
14957 }
14960 }
14971 else
14972 {
14976 /* In a template ~id could be either a complement expression
14977 or an unqualified-id naming a destructor; if instantiating
14978 it produces an expression, it's not an id-expression or
14979 member access. */
14982 }
14987 }
14990 {
14994 }
14998 {
14999 tree r;
15003 else
15011 }
15026 /* We should use one of the expression tsubsts for these codes. */
15032 }
15033 }
15035 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15036 expression on the left-hand side of the "." or "->" operator. We
15037 only do the lookup if we had a dependent BASELINK. Otherwise we
15038 adjust it onto the instantiated heirarchy. */
15040 static tree
15043 {
15055 {
15062 }
15069 {
15075 /* Treat as-if non-dependent below. */
15080 {
15086 }
15090 }
15091 else
15092 /* We're going to overwrite pieces below, make a duplicate. */
15095 /* If lookup found a single function, mark it as used at this point.
15096 (If lookup found multiple functions the one selected later by
15097 overload resolution will be marked as used at that point.) */
15099 {
15105 /* We might have instantiated an auto function. */
15107 }
15110 {
15111 /* Add back the template arguments, if present. */
15116 /* Update the conversion operator type. */
15118 }
15124 {
15126 qualifying_scope,
15127 object_type);
15129 /* We need to call adjust_result_of_qualified_name_lookup in case the
15130 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15131 so that we still get virtual function binding. */
15133 }
15136 }
15138 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15139 true if the qualified-id will be a postfix-expression in-and-of
15140 itself; false if more of the postfix-expression follows the
15141 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15142 of "&". */
15144 static tree
15148 {
15149 tree expr;
15150 tree scope;
15151 tree name;
15153 tree template_args;
15158 /* Figure out what name to look up. */
15161 {
15171 }
15172 else
15173 {
15176 }
15178 /* Substitute into the qualifying scope. When there are no ARGS, we
15179 are just trying to simplify a non-dependent expression. In that
15180 case the qualifying scope may be dependent, and, in any case,
15181 substituting will not help. */
15184 {
15187 }
15188 else
15192 {
15199 }
15202 {
15204 {
15205 /* A BIT_NOT_EXPR is used to represent a destructor. */
15207 {
15211 }
15212 else
15215 }
15216 else
15220 {
15222 {
15226 }
15228 }
15229 }
15232 {
15234 scope);
15235 /* Remember that there was a reference to this entity. */
15238 }
15241 {
15247 }
15250 {
15251 /* We may be repeating a check already done during parsing, but
15252 if it was well-formed and passed then, it will pass again
15253 now, and if it didn't, we wouldn't have got here. The case
15254 we want to catch is when we couldn't tell then, and can now,
15255 namely when templ prior to substitution was an
15256 identifier. */
15262 complain);
15263 else
15265 }
15271 {
15272 expr = (adjust_result_of_qualified_name_lookup
15274 expr = (finish_qualified_id_expr
15278 }
15280 /* Expressions do not generally have reference type. */
15282 /* However, if we're about to form a pointer-to-member, we just
15283 want the referenced member referenced. */
15291 }
15293 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15294 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15295 for tsubst. */
15297 static tree
15300 {
15307 {
15308 /* If we had an initializer but it
15309 instantiated to nothing,
15310 value-initialize the object. This will
15311 only occur when the initializer was a
15312 pack expansion where the parameter packs
15313 used in that expansion were of length
15314 zero. */
15316 complain);
15321 }
15324 }
15326 /* Like tsubst, but deals with expressions. This function just replaces
15327 template parms; to finish processing the resultant expression, use
15328 tsubst_copy_and_build or tsubst_expr. */
15330 static tree
15332 {
15334 tree r;
15342 {
15347 {
15348 /* We get here for a use of 'this' in an NSDMI. */
15352 /* This can happen for a parameter name used later in a function
15353 declaration (such as in a late-specified return type). Just
15354 make a dummy decl, since it's only used for its type. */
15357 /* Give it the template pattern as its context; its true context
15358 hasn't been instantiated yet and this is good enough for
15359 mangling. */
15361 }
15370 {
15371 tree enum_type;
15372 tree v;
15376 /* There is no need to substitute into namespace-scope
15377 enumerators. */
15380 /* If ARGS is NULL, then T is known to be non-dependent. */
15384 /* Unfortunately, we cannot just call lookup_name here.
15385 Consider:
15387 template <int I> int f() {
15388 enum E { a = I };
15389 struct S { void g() { E e = a; } };
15390 };
15392 When we instantiate f<7>::S::g(), say, lookup_name is not
15393 clever enough to find f<7>::a. */
15394 enum_type
15404 /* We didn't find the name. That should never happen; if
15405 name-lookup found it during preliminary parsing, we
15406 should find it again here during instantiation. */
15408 }
15413 {
15414 tree ctx;
15419 {
15422 {
15426 }
15428 }
15429 }
15439 {
15442 {
15443 /* First try name lookup to find the instantiation. */
15446 {
15447 /* Make sure that the one we found is the one we want. */
15451 }
15455 else
15456 {
15457 /* This can happen for a variable used in a
15458 late-specified return type of a local lambda, or for a
15459 local static or constant. Building a new VAR_DECL
15460 should be OK in all those cases. */
15463 /* Avoid infinite recursion (79640). */
15466 {
15467 /* We can't call cp_finish_decl, so handle the
15468 initializer by hand. */
15483 }
15490 }
15491 /* Remember this for subsequent uses. */
15494 }
15497 }
15498 else
15508 /* An OVERLOAD will always be a non-dependent overload set; an
15509 overload set from function scope will just be represented with an
15510 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15512 /* We must have marked any lookups as persistent. */
15528 {
15529 /* Template template argument like the following example need
15530 special treatment:
15532 template <template <class> class TT> struct C {};
15533 template <class T> struct D {
15534 template <class U> struct E {};
15535 C<E> c; // #1
15536 };
15537 D<int> d; // #2
15539 We are processing the template argument `E' in #1 for
15540 the template instantiation #2. Originally, `E' is a
15541 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15542 have to substitute this with one having context `D<int>'. */
15546 {
15547 /* When rewriting a constructor into a deduction guide, a
15548 non-dependent name can become dependent, so memtmpl<args>
15549 becomes context::template memtmpl<args>. */
15553 }
15555 }
15556 else
15557 /* Ordinary template template argument. */
15562 {
15563 /* Handle location wrappers by substituting the wrapped node
15564 first, *then* reusing the resulting type. Doing the type
15565 first ensures that we handle template parameters and
15566 parameter pack expansions. */
15570 }
15580 {
15584 }
15589 {
15598 /* We only want to compute the number of arguments. */
15601 else
15608 {
15610 /* Set TREE_USED for the benefit of -Wunused. */
15614 }
15622 {
15627 else
15634 else
15637 }
15638 else
15640 }
15642 {
15650 }
15651 /* Fall through */
15667 {
15674 }
15677 {
15678 tree object;
15679 tree name;
15684 {
15688 }
15691 {
15701 }
15706 in_decl);
15707 else
15710 }
15748 {
15752 }
15755 {
15760 }
15763 {
15767 }
15770 {
15778 }
15784 {
15791 }
15794 {
15801 }
15804 {
15811 }
15814 {
15815 /* Substituted template arguments */
15824 }
15827 {
15847 }
15872 /* Fall through. */
15875 {
15878 }
15879 else
15883 /* This is handled by tsubst_copy_and_build. */
15887 {
15891 }
15894 /* We shouldn't have built any of these during initial template
15895 generation. Instead, they should be built during instantiation
15896 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15900 {
15910 }
15928 {
15929 /* Instantiate any typedefs in the type. */
15934 }
15937 /* These can sometimes show up in a partial instantiation, but never
15938 involve template parms. */
15954 /* ??? There's no point in copying it for now, but maybe some
15955 day it will contain more information, such as a pointer back
15956 to the containing function, inlined copy or so. */
15960 /* We shouldn't get here, but keep going if !flag_checking. */
15964 }
15965 }
15967 /* Helper function for tsubst_omp_clauses, used for instantiation of
15968 OMP_CLAUSE_DECL of clauses. */
15970 static tree
15972 tree in_decl)
15973 {
15977 /* Handle an OpenMP array section represented as a TREE_LIST (or
15978 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15979 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15980 TREE_LIST. We can handle it exactly the same as an array section
15981 (purpose, value, and a chain), even though the nomenclature
15982 (low_bound, length, etc) is different. */
15984 {
15985 tree low_bound
15991 in_decl);
16000 }
16003 /* Undo convert_from_reference tsubst_expr could have called. */
16009 }
16011 /* Like tsubst_copy, but specifically for OpenMP clauses. */
16013 static tree
16016 {
16021 {
16027 {
16030 {
16036 }
16037 /* FALLTHRU */
16052 in_decl);
16084 {
16087 {
16094 }
16095 else
16097 }
16100 in_decl);
16106 in_decl);
16114 in_decl);
16116 {
16119 }
16124 else
16127 in_decl,
16153 }
16156 {
16166 /* tsubst_expr on SCOPE_REF results in returning
16167 finish_non_static_data_member result. Undo that here. */
16171 {
16176 {
16180 CASE_CONVERT:
16189 /* FALLTHRU */
16193 }
16194 }
16200 {
16203 {
16206 }
16207 }
16211 }
16212 }
16216 {
16221 {
16224 }
16225 }
16227 }
16229 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16231 static tree
16233 tree in_decl)
16234 {
16235 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16255 {
16258 else
16259 {
16263 }
16264 }
16269 #undef RECUR
16270 }
16272 /* Used to temporarily communicate the list of #pragma omp parallel
16273 clauses to #pragma omp for instantiation if they are combined
16274 together. */
16278 /* Substitute one OMP_FOR iterator. */
16280 static void
16285 {
16286 #define RECUR(NODE) \
16287 tsubst_expr ((NODE), args, complain, in_decl, \
16288 integral_constant_expression_p)
16295 {
16301 else
16303 }
16309 {
16310 /* We need to jump through some hoops to handle declarations in the
16311 init-statement, since we might need to handle auto deduction,
16312 but we need to keep control of initialization. */
16316 }
16317 else
16318 {
16320 {
16323 {
16327 {
16331 CASE_CONVERT:
16339 {
16342 }
16343 /* FALLTHRU */
16347 }
16348 }
16349 }
16350 else
16352 }
16363 {
16365 {
16366 /* Declare the variable, but don't let that initialize it. */
16371 }
16376 {
16381 }
16382 else
16389 }
16392 {
16393 /* Declare and initialize the variable. */
16396 }
16398 {
16402 {
16404 {
16410 {
16413 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16418 }
16421 {
16423 decl);
16425 }
16428 {
16430 decl);
16432 }
16433 else
16435 }
16438 }
16440 {
16445 {
16448 }
16449 }
16450 }
16453 {
16457 }
16458 else
16462 {
16473 {
16481 }
16482 else
16488 {
16494 }
16498 {
16506 }
16507 else
16513 }
16519 #undef RECUR
16520 }
16522 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16523 of OMP_TARGET's body. */
16525 static tree
16527 {
16530 {
16539 }
16541 }
16543 /* Helper function for tsubst_expr. For decomposition declaration
16544 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16545 also the corresponding decls representing the identifiers
16546 of the decomposition declaration. Return DECL if successful
16547 or error_mark_node otherwise, set *FIRST to the first decl
16548 in the list chained through DECL_CHAIN and *CNT to the number
16549 of such decls. */
16551 static tree
16555 {
16560 decl2
16565 {
16567 {
16570 }
16582 else
16583 {
16587 }
16594 {
16597 }
16598 else
16600 }
16603 }
16605 /* Like tsubst_copy for expressions, etc. but also does semantic
16606 processing. */
16608 tree
16611 {
16612 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16613 #define RECUR(NODE) \
16614 tsubst_expr ((NODE), args, complain, in_decl, \
16615 integral_constant_expression_p)
16618 tree r;
16619 location_t loc;
16631 {
16633 {
16634 tree_stmt_iterator i;
16638 }
16653 else
16663 {
16665 tree init;
16671 {
16681 else
16683 }
16686 {
16687 /* We're in tsubst_lambda_expr, we've already inserted a new
16688 capture proxy, so look it up and register it. */
16689 tree inst;
16691 {
16692 inst = (retrieve_local_specialization
16695 }
16696 else
16697 {
16701 }
16704 }
16707 /* Don't copy the old closure; we'll create a new one in
16708 tsubst_lambda_expr. */
16710 else
16711 {
16715 {
16716 /* By marking the declaration as instantiated, we avoid
16717 trying to instantiate it. Since instantiate_decl can't
16718 handle local variables, and since we've already done
16719 all that needs to be done, that's the right thing to
16720 do. */
16725 /* Anonymous aggregates are a special case. */
16728 {
16731 {
16735 }
16737 }
16743 {
16748 }
16749 else
16750 {
16765 {
16766 /* For __PRETTY_FUNCTION__ we have to adjust the
16767 initializer. */
16771 }
16772 else
16776 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16786 }
16787 }
16788 }
16791 }
16801 {
16805 }
16810 {
16811 /* Construct another range_for, if this is not a final
16812 substitution (for inside inside a generic lambda of a
16813 template). Otherwise convert to a regular for. */
16815 stmt = (processing_template_decl
16832 {
16838 }
16839 else
16840 {
16846 }
16852 }
16859 {
16863 }
16869 {
16873 }
16888 {
16889 /* We're partially instantiating a generic lambda, but the condition
16890 of the constexpr if is still dependent. Don't substitute into the
16891 branches now, just remember the template arguments. */
16899 }
16902 else
16903 {
16911 }
16917 {
16927 }
16935 else
16943 else
16964 {
16971 }
16975 {
16977 tree label;
16984 }
16990 /* Computed goto's must be tsubst'd into. On the other hand,
16991 non-computed gotos must not be; the identifier in question
16992 will have no binding. */
16994 else
17000 {
17016 }
17021 {
17026 }
17027 else
17028 {
17033 else
17040 else
17046 else
17048 }
17052 {
17056 {
17058 /* Prevent instantiate_decl from trying to instantiate
17059 this variable. We've already done all that needs to be
17060 done. */
17063 }
17068 }
17074 {
17075 /* Local classes are not independent templates; they are
17076 instantiated along with their containing function. And this
17077 way we don't have to deal with pushing out of one local class
17078 to instantiate a member of another local class. */
17079 /* Closures are handled by the LAMBDA_EXPR. */
17089 }
17093 {
17094 tree condition;
17097 condition =
17099 args,
17108 }
17114 in_decl);
17149 {
17162 in_decl);
17164 {
17171 }
17183 integral_constant_expression_p);
17194 else
17195 {
17203 }
17207 }
17212 /* FALLTHRU */
17219 in_decl);
17236 in_decl);
17247 {
17250 {
17251 /* For combined target teams, ensure the num_teams and
17252 thread_limit clause expressions are evaluated on the host,
17253 before entering the target construct. */
17254 tree c;
17260 {
17269 OMP_CLAUSE_FIRSTPRIVATE);
17273 }
17274 }
17275 }
17335 {
17340 {
17343 }
17349 }
17350 else
17351 {
17358 {
17361 }
17364 {
17369 {
17372 }
17378 }
17379 else
17380 {
17384 }
17387 }
17391 {
17397 {
17401 {
17406 }
17410 }
17411 else
17412 {
17417 }
17418 }
17422 {
17426 }
17439 /* If the first operand was a statement, we're done with it. */
17443 complain));
17457 integral_constant_expression_p));
17458 }
17461 out:
17464 #undef RECUR
17465 #undef RETURN
17466 }
17468 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17469 function. For description of the body see comment above
17470 cp_parser_omp_declare_reduction_exprs. */
17472 static void
17474 {
17480 tree_stmt_iterator tsi;
17491 {
17510 }
17512 {
17532 }
17533 }
17535 /* T is a postfix-expression that is not being used in a function
17536 call. Return the substituted version of T. */
17538 static tree
17540 tsubst_flags_t complain,
17541 tree in_decl)
17542 {
17546 else
17552 }
17554 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17555 instantiation context. Instantiating a pack expansion containing a lambda
17556 might result in multiple lambdas all based on the same lambda in the
17557 template. */
17559 tree
17561 {
17574 /* A lambda in a default argument outside a class gets no
17575 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
17576 tsubst_default_argument calls start_lambda_scope, so we need to
17577 specifically ignore it here, and use the global scope. */
17579 else
17587 {
17599 else
17604 {
17613 }
17614 else
17615 {
17621 }
17622 }
17628 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17646 else
17647 {
17648 /* Fix the type of 'this'. */
17654 {
17658 }
17659 else
17660 {
17664 }
17666 /* Let finish_function set this. */
17672 else
17673 /* Still increment function_depth so that we don't GC in the
17674 middle of an expression. */
17684 {
17685 /* We might not partially instantiate some parts of the function, so
17686 copy these flags from the original template. */
17692 }
17701 else
17704 /* The capture list was built up in reverse order; fix that now. */
17711 }
17718 }
17720 /* Like tsubst but deals with expressions and performs semantic
17721 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17723 tree
17725 tree args,
17726 tsubst_flags_t complain,
17727 tree in_decl,
17730 {
17731 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17732 #define RECUR(NODE) \
17733 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17735 integral_constant_expression_p)
17738 location_t loc;
17747 /* N3276 decltype magic only applies to calls at the top level or on the
17748 right side of a comma. */
17753 {
17756 /* Fall through. */
17758 {
17759 tree decl;
17760 cp_id_kind idk;
17765 {
17768 }
17770 /* Look up the name. */
17773 /* By convention, expressions use ERROR_MARK_NODE to indicate
17774 failure, not NULL_TREE. */
17780 integral_constant_expression_p,
17788 input_location);
17792 {
17796 }
17798 }
17801 {
17802 tree object;
17812 {
17817 }
17823 {
17826 }
17827 else
17834 else
17836 }
17839 {
17843 {
17844 /* A type conversion to reference type will be enclosed in
17845 such an indirect ref, but the substitution of the cast
17846 will have also added such an indirect ref. */
17848 }
17849 else
17857 }
17860 {
17864 }
17867 {
17871 {
17876 }
17878 /* We'll pass this to convert_nontype_argument again, we don't need
17879 to actually perform any conversion here. */
17885 flags));
17886 }
17889 {
17895 }
17902 {
17903 tree type;
17909 {
17914 }
17921 {
17939 }
17942 }
17975 else
17977 in_decl);
18012 {
18019 tree r = build_x_binary_op
18021 op0,
18023 ? ERROR_MARK
18025 op1,
18027 ? ERROR_MARK
18035 }
18038 {
18042 }
18058 /* Fall through */
18061 {
18062 tree r;
18070 {
18071 /* When there are no ARGS, we are trying to evaluate a
18072 non-dependent expression from the parser. Trying to do
18073 the substitutions may not work. */
18076 }
18077 else
18078 {
18083 else
18086 /*integral_constant_expression_p=*/
18090 }
18094 else
18098 {
18100 {
18102 {
18106 }
18107 else
18111 }
18113 }
18115 }
18118 {
18128 }
18144 {
18148 tree r = build_x_modify_expr
18151 /* TREE_NO_WARNING must be set if either the expression was
18152 parenthesized or it uses an operator such as >>= rather
18153 than plain assignment. In the former case, it was already
18154 set and must be copied. In the latter case,
18155 build_x_modify_expr sets it and it must not be reset
18156 here. */
18161 }
18166 /* Remember that there was a reference to this entity. */
18173 {
18178 tree ret;
18182 else
18183 {
18187 }
18189 /* If there was an initializer in the original tree, but it
18190 instantiated to an empty list, then we should pass a
18191 non-NULL empty vector to tell build_new that it was an
18192 empty initializer() rather than no initializer. This can
18193 only happen when the initializer is a pack expansion whose
18194 parameter packs are of length zero. */
18197 else
18198 {
18202 else
18203 {
18206 }
18207 }
18209 /* Avoid passing an enclosing decl to valid_array_size_p. */
18216 complain);
18224 }
18227 {
18233 complain));
18234 }
18237 {
18241 integral_constant_expression_p);
18243 op0,
18246 }
18249 {
18250 tree function;
18255 tree ret;
18258 /* Internal function with no arguments. */
18262 /* When we parsed the expression, we determined whether or
18263 not Koenig lookup should be performed. */
18266 {
18269 }
18271 {
18276 }
18278 {
18279 /* Do nothing; calling tsubst_copy_and_build on an identifier
18280 would incorrectly perform unqualified lookup again.
18282 Note that we can also have an IDENTIFIER_NODE if the earlier
18283 unqualified lookup found a member function; in that case
18284 koenig_p will be false and we do want to do the lookup
18285 again to find the instantiated member function.
18287 FIXME but doing that causes c++/15272, so we need to stop
18288 using IDENTIFIER_NODE in that situation. */
18290 }
18291 else
18292 {
18294 {
18300 }
18301 else
18306 /* Avoid error about taking the address of a constructor. */
18310 in_decl,
18312 integral_constant_expression_p);
18316 }
18321 {
18326 else
18327 {
18328 /* Expand the pack expansion and push each entry onto
18329 CALL_ARGS. */
18332 {
18337 {
18342 }
18343 }
18344 else
18345 {
18346 /* A partial substitution. Add one entry. */
18348 }
18349 }
18350 }
18352 /* We do not perform argument-dependent lookup if normal
18353 lookup finds a non-function, in accordance with the
18354 expected resolution of DR 218. */
18357 /* If lookup found a member function, the Koenig lookup is
18358 not appropriate, even if an unqualified-name was used
18359 to denote the function. */
18362 /* Only do this when substitution turns a dependent call
18363 into a non-dependent call. */
18371 {
18373 {
18374 /* For backwards compatibility and good diagnostics, try
18375 the unqualified lookup again if we aren't in SFINAE
18376 context. */
18377 tree unq = (tsubst_copy_and_build
18379 integral_constant_expression_p));
18381 {
18384 }
18387 {
18388 /* In a lambda fn, we have to be careful to not
18389 introduce new this captures. Legacy code can't
18390 be using lambdas anyway, so it's ok to be
18391 stricter. */
18396 "and no declarations were found by "
18397 "argument-dependent lookup at the point "
18404 else
18408 {
18419 {
18421 input_location);
18423 "declarations in dependent base %qT are "
18429 else
18433 }
18434 else
18436 "%qD declared here, later in the "
18439 {
18442 }
18443 }
18446 }
18447 }
18449 {
18454 }
18455 }
18457 /* Remember that there was a reference to this entity. */
18461 {
18464 }
18466 /* Put back tf_decltype for the actual call. */
18471 {
18475 {
18477 "wrong number of arguments to "
18480 }
18481 else
18483 input_location),
18488 /* Unsupported internal function with arguments. */
18490 }
18495 complain);
18497 {
18512 complain);
18513 else
18514 ret = (build_new_method_call
18519 complain));
18520 }
18521 else
18524 koenig_p,
18525 complain);
18530 {
18536 {
18542 {
18545 else
18547 /* The thunk location is not interesting. */
18549 }
18550 }
18551 }
18554 }
18557 {
18564 {
18566 {
18571 }
18572 else
18573 {
18578 }
18580 }
18581 else
18582 {
18585 }
18590 }
18593 {
18598 input_location));
18599 }
18602 {
18610 {
18611 /* We have pack expansions, so expand those and
18612 create a new list out of it. */
18615 tree chain;
18618 /* Expand the argument expressions. */
18626 /* Build the rest of the list. */
18631 /* Determine the number of arguments. */
18633 {
18636 }
18639 else
18640 {
18641 /* Since we only performed a partial substitution into
18642 the argument pack, we only RETURN (a single list
18643 node. */
18650 }
18652 /* Convert the argument vectors into a TREE_LIST */
18655 {
18656 /* Grab the Ith values. */
18657 i--;
18660 value
18664 /* Build the list (backwards). */
18666 }
18669 }
18685 }
18688 {
18689 tree object;
18690 tree object_type;
18691 tree member;
18692 tree r;
18696 /* Remember that there was a reference to this entity. */
18707 else
18713 {
18718 }
18722 {
18724 {
18729 {
18732 }
18734 {
18739 }
18740 }
18741 }
18744 {
18745 /* Lookup the template functions now that we know what the
18746 scope is. */
18754 {
18757 args);
18758 member = (adjust_result_of_qualified_name_lookup
18760 object_type));
18761 }
18762 else
18763 {
18765 input_location);
18767 }
18768 }
18772 {
18774 {
18778 else
18781 }
18783 }
18787 complain);
18791 }
18798 {
18806 tree r;
18811 /* We do not want to process the index of aggregate
18812 initializers as they are identifier nodes which will be
18813 looked up by digest_init. */
18819 {
18821 /* An identifier index is looked up in the type
18822 being initialized, not the current scope. */
18827 {
18828 /* Substitute into the pack expansion. */
18830 in_decl);
18834 ;
18836 /* Just move the argument into place. */
18838 else
18839 {
18840 /* Update the length of the final CONSTRUCTOR
18841 arguments vector, and note that we will need to
18842 copy.*/
18845 }
18846 }
18847 else
18849 }
18852 {
18857 {
18859 {
18864 }
18865 else
18867 }
18868 }
18874 {
18879 }
18883 }
18886 {
18889 {
18892 }
18893 else
18894 {
18897 }
18898 }
18903 /* Fall through */
18906 {
18908 /* ??? We're doing a subset of finish_id_expression here. */
18910 && !processing_template_decl
18911 && !cp_unevaluated_operand
18914 {
18916 /* Replace an evaluated use of the thread_local variable with
18917 a call to its wrapper. */
18919 }
18924 /* If the original type was a reference, we'll be wrapped in
18925 the appropriate INDIRECT_REF. */
18928 }
18931 {
18935 }
18938 {
18939 tree object_ptr
18946 }
18953 {
18964 }
18967 {
18973 integral_constant_expression_p);
18977 /* If the resulting list of expression statement is empty,
18978 fold it further into void_node. */
18983 }
18986 {
18990 }
18993 /* We can get here for a constant initializer of non-dependent type.
18994 FIXME stop folding in cp_parser_initializer_clause. */
18995 {
18997 complain);
18999 }
19003 integral_constant_expression_p));
19009 {
19014 complain));
19015 }
19022 /* We should only see these for location wrapper nodes, or within
19023 instantiate_non_dependent_expr (when args is NULL_TREE). */
19028 /* fallthrough. */
19031 /* Handle Objective-C++ constructs, if appropriate. */
19032 {
19033 tree subst
19038 }
19040 }
19042 #undef RECUR
19043 #undef RETURN
19044 out:
19047 }
19049 /* Verify that the instantiated ARGS are valid. For type arguments,
19050 make sure that the type's linkage is ok. For non-type arguments,
19051 make sure they are constants if they are integral or enumerations.
19052 Emit an error under control of COMPLAIN, and return TRUE on error. */
19054 static bool
19056 {
19060 {
19070 }
19072 {
19073 /* [basic.link]: A name with no linkage (notably, the name
19074 of a class or enumeration declared in a local scope)
19075 shall not be used to declare an entity with linkage.
19076 This implies that names with no linkage cannot be used as
19077 template arguments
19079 DR 757 relaxes this restriction for C++0x. */
19084 {
19085 /* DR 488 makes use of a type with no linkage cause
19086 type deduction to fail. */
19088 {
19091 else
19094 }
19096 }
19097 /* In order to avoid all sorts of complications, we do not
19098 allow variably-modified types as template arguments. */
19100 {
19104 }
19105 }
19106 /* Class template and alias template arguments should be OK. */
19108 ;
19109 /* A non-type argument of integral or enumerated type must be a
19110 constant. */
19115 {
19119 }
19121 }
19123 static bool
19125 {
19130 {
19133 }
19137 }
19139 /* We're out of SFINAE context now, so generate diagnostics for the access
19140 errors we saw earlier when instantiating D from TMPL and ARGS. */
19142 static void
19144 {
19156 }
19158 /* Instantiate the indicated variable, function, or alias template TMPL with
19159 the template arguments in TARG_PTR. */
19161 static tree
19163 {
19165 tree fndecl;
19166 tree gen_tmpl;
19167 tree spec;
19175 /* If this function is a clone, handle it specially. */
19177 {
19178 tree spec;
19179 tree clone;
19181 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19182 DECL_CLONED_FUNCTION. */
19188 /* Look for the clone. */
19192 /* We should always have found the clone by now. */
19195 }
19200 /* Check to see if we already have this specialization. */
19204 /* targ_ptr only has the innermost template args, so add the outer ones
19205 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19206 the case of a non-dependent call within a template definition). */
19207 targ_ptr = (add_outermost_template_args
19209 targ_ptr));
19211 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19212 but it doesn't seem to be on the hot path. */
19221 {
19223 {
19227 }
19229 }
19232 complain))
19235 /* We are building a FUNCTION_DECL, during which the access of its
19236 parameters and return types have to be checked. However this
19237 FUNCTION_DECL which is the desired context for access checking
19238 is not built yet. We solve this chicken-and-egg problem by
19239 deferring all checks until we have the FUNCTION_DECL. */
19242 /* Instantiation of the function happens in the context of the function
19243 template, not the context of the overload resolution we're doing. */
19245 /* If there are dependent arguments, e.g. because we're doing partial
19246 ordering, make sure processing_template_decl stays set. */
19250 {
19254 }
19260 {
19261 /* We need to determine if we're using a partial or explicit
19262 specialization now, because the type of the variable could be
19263 different. */
19269 {
19274 }
19275 }
19277 /* Substitute template parameters to obtain the specialization. */
19285 {
19288 }
19290 /* The DECL_TI_TEMPLATE should always be the immediate parent
19291 template, not the most general template. */
19295 /* Now we know the specialization, compute access previously
19296 deferred. Do no access control for inheriting constructors,
19297 as we already checked access for the inherited constructor. */
19300 {
19305 }
19308 /* If we've just instantiated the main entry point for a function,
19309 instantiate all the alternate entry points as well. We do this
19310 by cloning the instantiation of the main entry point, not by
19311 instantiating the template clones. */
19316 {
19318 {
19319 /* Remember to reinstantiate when we're out of SFINAE so the user
19320 can see the errors. */
19322 }
19324 }
19326 }
19328 /* Wrapper for instantiate_template_1. */
19330 tree
19332 {
19333 tree ret;
19338 }
19340 /* Instantiate the alias template TMPL with ARGS. Also push a template
19341 instantiation level, which instantiate_template doesn't do because
19342 functions and variables have sufficient context established by the
19343 callers. */
19345 static tree
19347 {
19353 args =
19363 }
19365 /* PARM is a template parameter pack for FN. Returns true iff
19366 PARM is used in a deducible way in the argument list of FN. */
19368 static bool
19370 {
19373 {
19375 tree packs;
19381 {
19382 /* The template parameter pack is used in a function parameter
19383 pack. If this is the end of the parameter list, the
19384 template parameter pack is deducible. */
19387 else
19388 /* Otherwise, not. Well, it could be deduced from
19389 a non-pack parameter, but doing so would end up with
19390 a deduction mismatch, so don't bother. */
19392 }
19393 }
19394 /* The template parameter pack isn't used in any function parameter
19395 packs, but it might be used deeper, e.g. tuple<Args...>. */
19397 }
19399 /* Subroutine of fn_type_unification: check non-dependent parms for
19400 convertibility. */
19402 static int
19406 {
19407 /* Non-constructor methods need to leave a conversion for 'this', which
19408 isn't included in nargs here. */
19414 {
19420 /* For a function parameter pack that occurs at the end of the
19421 parameter-declaration-list, the type A of each remaining
19422 argument of the call is compared with the type P of the
19423 declarator-id of the function parameter pack. */
19429 /* For a function parameter pack that does not occur at the
19430 end of the parameter-declaration-list, the type of the
19431 parameter pack is a non-deduced context. */
19435 {
19443 }
19446 }
19449 }
19451 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19452 NARGS elements of the arguments that are being used when calling
19453 it. TARGS is a vector into which the deduced template arguments
19454 are placed.
19456 Returns either a FUNCTION_DECL for the matching specialization of FN or
19457 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19458 true, diagnostics will be printed to explain why it failed.
19460 If FN is a conversion operator, or we are trying to produce a specific
19461 specialization, RETURN_TYPE is the return type desired.
19463 The EXPLICIT_TARGS are explicit template arguments provided via a
19464 template-id.
19466 The parameter STRICT is one of:
19468 DEDUCE_CALL:
19469 We are deducing arguments for a function call, as in
19470 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19471 deducing arguments for a call to the result of a conversion
19472 function template, as in [over.call.object].
19474 DEDUCE_CONV:
19475 We are deducing arguments for a conversion function, as in
19476 [temp.deduct.conv].
19478 DEDUCE_EXACT:
19479 We are deducing arguments when doing an explicit instantiation
19480 as in [temp.explicit], when determining an explicit specialization
19481 as in [temp.expl.spec], or when taking the address of a function
19482 template, as in [temp.deduct.funcaddr]. */
19484 tree
19486 tree explicit_targs,
19487 tree targs,
19490 tree return_type,
19491 unification_kind_t strict,
19496 {
19497 tree parms;
19498 tree fntype;
19514 full_targs = (add_outermost_template_args
19516 targs));
19521 /* In C++0x, it's possible to have a function template whose type depends
19522 on itself recursively. This is most obvious with decltype, but can also
19523 occur with enumeration scope (c++/48969). So we need to catch infinite
19524 recursion and reject the substitution at deduction time; this function
19525 will return error_mark_node for any repeated substitution.
19527 This also catches excessive recursion such as when f<N> depends on
19528 f<N-1> across all integers, and returns error_mark_node for all the
19529 substitutions back up to the initial one.
19531 This is, of course, not reentrant. */
19540 {
19541 /* [temp.deduct]
19543 The specified template arguments must match the template
19544 parameters in kind (i.e., type, nontype, template), and there
19545 must not be more arguments than there are parameters;
19546 otherwise type deduction fails.
19548 Nontype arguments must match the types of the corresponding
19549 nontype template parameters, or must be convertible to the
19550 types of the corresponding nontype parameters as specified in
19551 _temp.arg.nontype_, otherwise type deduction fails.
19553 All references in the function type of the function template
19554 to the corresponding template parameters are replaced by the
19555 specified template argument values. If a substitution in a
19556 template parameter or in the function type of the function
19557 template results in an invalid type, type deduction fails. */
19568 explicit_targs);
19570 /* Adjust any explicit template arguments before entering the
19571 substitution context. */
19572 explicit_targs
19574 complain,
19580 /* Substitute the explicit args into the function type. This is
19581 necessary so that, for instance, explicitly declared function
19582 arguments can match null pointed constants. If we were given
19583 an incomplete set of explicit args, we must not do semantic
19584 processing during substitution as we could create partial
19585 instantiations. */
19587 {
19592 /* Dig out the actual parm. */
19595 {
19598 }
19600 {
19603 }
19606 /* No explicit argument for this template parameter. */
19610 {
19611 /* Mark the argument pack as "incomplete". We could
19612 still deduce more arguments during unification.
19613 We remove this mark in type_unification_real. */
19615 {
19619 }
19621 /* We have some incomplete argument packs. */
19623 }
19624 }
19627 {
19630 }
19633 /* Ignore any access checks; we'll see them again in
19634 instantiate_template and they might have the wrong
19635 access path at this point. */
19647 /* Place the explicitly specified arguments in TARGS. */
19651 }
19653 /* Never do unification on the 'this' parameter. */
19657 {
19658 /* We're deducing for a call to the result of a template conversion
19659 function. The parms we really want are in return_type. */
19663 }
19665 {
19674 }
19676 /* We allow incomplete unification without an error message here
19677 because the standard doesn't seem to explicitly prohibit it. Our
19678 callers must be ready to deal with unification failures in any
19679 event. */
19681 /* If we aren't explaining yet, push tinst context so we can see where
19682 any errors (e.g. from class instantiations triggered by instantiation
19683 of default template arguments) come from. If we are explaining, this
19684 context is redundant. */
19686 {
19689 }
19691 /* type_unification_real will pass back any access checks from default
19692 template argument substitution. */
19704 /* Now that we have bindings for all of the template arguments,
19705 ensure that the arguments deduced for the template template
19706 parameters have compatible template parameter lists. We cannot
19707 check this property before we have deduced all template
19708 arguments, because the template parameter types of a template
19709 template parameter might depend on prior template parameters
19710 deduced after the template template parameter. The following
19711 ill-formed example illustrates this issue:
19713 template<typename T, template<T> class C> void f(C<5>, T);
19715 template<int N> struct X {};
19717 void g() {
19718 f(X<5>(), 5l); // error: template argument deduction fails
19719 }
19721 The template parameter list of 'C' depends on the template type
19722 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19723 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19724 time that we deduce 'C'. */
19727 {
19730 }
19732 /* DR 1391: All parameters have args, now check non-dependent parms for
19733 convertibility. */
19738 /* All is well so far. Now, check:
19740 [temp.deduct]
19742 When all template arguments have been deduced, all uses of
19743 template parameters in nondeduced contexts are replaced with
19744 the corresponding deduced argument values. If the
19745 substitution results in an invalid type, as described above,
19746 type deduction fails. */
19748 {
19751 }
19753 /* Also collect access checks from the instantiation. */
19766 /* Now perform any access checks encountered during substitution. */
19773 /* If we're looking for an exact match, check that what we got
19774 is indeed an exact match. It might not be if some template
19775 parameters are used in non-deduced contexts. But don't check
19776 for an exact match if we have dependent template arguments;
19777 in that case we're doing partial ordering, and we already know
19778 that we have two candidates that will provide the actual type. */
19780 {
19784 tree sarg
19790 {
19794 }
19795 }
19797 /* After doing deduction with the inherited constructor, actually return an
19798 instantiation of the inheriting constructor. */
19804 fail:
19807 {
19809 /* Reset once we're all the way out. */
19811 }
19814 }
19816 /* Adjust types before performing type deduction, as described in
19817 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19818 sections are symmetric. PARM is the type of a function parameter
19819 or the return type of the conversion function. ARG is the type of
19820 the argument passed to the call, or the type of the value
19821 initialized with the result of the conversion function.
19822 ARG_EXPR is the original argument expression, which may be null. */
19824 static int
19828 tree arg_expr)
19829 {
19833 {
19838 /* Swap PARM and ARG throughout the remainder of this
19839 function; the handling is precisely symmetric since PARM
19840 will initialize ARG rather than vice versa. */
19845 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19846 too, but here handle it by stripping the reference from PARM
19847 rather than by adding it to ARG. */
19855 /* Nothing else to do in this case. */
19860 }
19863 {
19864 /* [temp.deduct.call]
19866 If P is not a reference type:
19868 --If A is an array type, the pointer type produced by the
19869 array-to-pointer standard conversion (_conv.array_) is
19870 used in place of A for type deduction; otherwise,
19872 --If A is a function type, the pointer type produced by
19873 the function-to-pointer standard conversion
19874 (_conv.func_) is used in place of A for type deduction;
19875 otherwise,
19877 --If A is a cv-qualified type, the top level
19878 cv-qualifiers of A's type are ignored for type
19879 deduction. */
19884 else
19886 }
19888 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19889 reference to a cv-unqualified template parameter that does not represent a
19890 template parameter of a class template (during class template argument
19891 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19892 an lvalue, the type "lvalue reference to A" is used in place of A for type
19893 deduction. */
19900 /* try_one_overload doesn't provide an arg_expr, but
19901 functions are always lvalues. */
19905 /* [temp.deduct.call]
19907 If P is a cv-qualified type, the top level cv-qualifiers
19908 of P's type are ignored for type deduction. If P is a
19909 reference type, the type referred to by P is used for
19910 type deduction. */
19913 {
19916 }
19918 /* DR 322. For conversion deduction, remove a reference type on parm
19919 too (which has been swapped into ARG). */
19924 }
19926 /* Subroutine of fn_type_unification. PARM is a function parameter of a
19927 template which doesn't contain any deducible template parameters; check if
19928 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19929 unify_one_argument. */
19931 static int
19935 {
19936 tree type;
19940 else
19948 {
19951 }
19953 {
19957 /* Avoid recalculating this in add_function_candidate. */
19958 ok = (*conv_p
19960 else
19964 }
19968 else
19970 }
19974 /* Returns true iff the expression EXPR is one from which a template
19975 argument can be deduced. In other words, if it's an undecorated
19976 use of a template non-type parameter. */
19978 static bool
19980 {
19981 /* Strip implicit conversions. */
19985 }
19987 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19988 deducible way; that is, if it has a max value of <PARM> - 1. */
19990 static bool
19992 {
20001 }
20003 /* Returns true iff the template arguments ARGS use a template parameter
20004 in a deducible way. */
20006 static bool
20008 {
20010 {
20015 else
20016 {
20023 else
20025 }
20028 }
20030 }
20032 /* Returns true iff TYPE contains any deducible references to template
20033 parameters, as per 14.8.2.5. */
20035 static bool
20037 {
20041 /* T
20042 cv-list T
20043 TT<T>
20044 TT<i>
20045 TT<> */
20050 /* T*
20051 T&
20052 T&& */
20056 /* T[integer-constant ]
20057 type [i] */
20062 /* T type ::*
20063 type T::*
20064 T T::*
20065 T (type ::*)()
20066 type (T::*)()
20067 type (type ::*)(T)
20068 type (T::*)(T)
20069 T (type ::*)(T)
20070 T (T::*)()
20071 T (T::*)(T) */
20074 || (uses_deducible_template_parms
20077 /* template-name <T> (where template-name refers to a class template)
20078 template-name <i> (where template-name refers to a class template) */
20085 /* type (T)
20086 T()
20087 T(T) */
20090 {
20099 }
20102 }
20104 /* Subroutine of type_unification_real and unify_pack_expansion to
20105 handle unification of a single P/A pair. Parameters are as
20106 for those functions. */
20108 static int
20112 {
20119 /* We can't deduce anything from this, but we might get all the
20120 template args from other function args. */
20123 /* Implicit conversions (Clause 4) will be performed on a function
20124 argument to convert it to the type of the corresponding function
20125 parameter if the parameter type contains no template-parameters that
20126 participate in template argument deduction. */
20129 /* For function parameters with no deducible template parameters,
20130 just return. We'll check non-dependent conversions later. */
20134 {
20136 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20137 | UNIFY_ALLOW_MORE_CV_QUAL
20151 }
20153 /* We only do these transformations if this is the top-level
20154 parameter_type_list in a call or declaration matching; in other
20155 situations (nested function declarators, template argument lists) we
20156 won't be comparing a type to an expression, and we don't do any type
20157 adjustments. */
20159 {
20161 {
20164 {
20165 /* [temp.deduct.type] A template-argument can be
20166 deduced from a pointer to function or pointer
20167 to member function argument if the set of
20168 overloaded functions does not contain function
20169 templates and at most one of a set of
20170 overloaded functions provides a unique
20171 match. */
20175 /* If a unique match was not found, this is a
20176 non-deduced context, so we still succeed. */
20178 }
20184 }
20186 arg_strict |=
20188 }
20189 else
20194 /* For deduction from an init-list we need the actual list. */
20198 }
20200 /* for_each_template_parm callback that always returns 0. */
20202 static int
20204 {
20206 }
20208 /* for_each_template_parm any_fn callback to handle deduction of a template
20209 type argument from the type of an array bound. */
20211 static int
20213 {
20221 {
20227 }
20229 /* Keep walking. */
20231 }
20233 /* Try to deduce any not-yet-deduced template type arguments from the type of
20234 an array bound. This is handled separately from unify because 14.8.2.5 says
20235 "The type of a type parameter is only deduced from an array bound if it is
20236 not otherwise deduced." */
20238 static void
20240 {
20245 }
20247 /* Most parms like fn_type_unification.
20249 If SUBR is 1, we're being called recursively (to unify the
20250 arguments of a function or method parameter of a function
20251 template).
20253 CHECKS is a pointer to a vector of access checks encountered while
20254 substituting default template arguments. */
20256 static int
20258 tree full_targs,
20259 tree xparms,
20263 unification_kind_t strict,
20266 {
20271 tree parms;
20282 /* Reset the number of non-defaulted template arguments contained
20283 in TARGS. */
20286 again:
20294 {
20299 /* For a function parameter pack that occurs at the end of the
20300 parameter-declaration-list, the type A of each remaining
20301 argument of the call is compared with the type P of the
20302 declarator-id of the function parameter pack. */
20308 /* For a function parameter pack that does not occur at the
20309 end of the parameter-declaration-list, the type of the
20310 parameter pack is a non-deduced context. */
20317 explain_p))
20319 }
20324 {
20325 /* Unify the remaining arguments with the pack expansion type. */
20326 tree argvec;
20329 /* Allocate a TREE_VEC and copy in all of the arguments */
20334 /* Copy the parameter into parmvec. */
20340 /* Advance to the end of the list of parameters. */
20342 }
20344 /* Fail if we've reached the end of the parm list, and more args
20345 are present, and the parm list isn't variadic. */
20348 /* Fail if parms are left and they don't have default values and
20349 they aren't all deduced as empty packs (c++/57397). This is
20350 consistent with sufficient_parms_p. */
20353 {
20357 do
20358 {
20361 count++;
20363 }
20367 type_pack_p);
20368 }
20371 {
20372 tsubst_flags_t complain = (explain_p
20373 ? tf_warning_or_error
20378 {
20382 /* Clear the "incomplete" flags on all argument packs now so that
20383 substituting them into later default arguments works. */
20385 {
20388 }
20396 {
20401 }
20403 /* If this is an undeduced nontype parameter that depends on
20404 a type parameter, try another pass; its type may have been
20405 deduced from a later argument than the one from which
20406 this parameter can be deduced. */
20410 {
20413 }
20415 /* Core issue #226 (C++0x) [temp.deduct]:
20417 If a template argument has not been deduced, its
20418 default template argument, if any, is used.
20420 When we are in C++98 mode, TREE_PURPOSE will either
20421 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20422 to explicitly check cxx_dialect here. */
20424 /* OK, there is a default argument. Wait until after the
20425 conversion check to do substitution. */
20428 /* If the type parameter is a parameter pack, then it will
20429 be deduced to an empty parameter pack. */
20431 {
20432 tree arg;
20435 {
20438 }
20439 else
20446 }
20449 }
20451 /* Now substitute into the default template arguments. */
20453 {
20469 {
20470 /* The type of this non-type parameter depends on undeduced
20471 parameters. Don't try to use its default argument yet,
20472 since we might deduce an argument for it on the next pass,
20473 but do check whether the arguments we already have cause
20474 substitution failure, so that that happens before we try
20475 later default arguments (78489). */
20478 NULL_TREE);
20482 else
20484 }
20485 else
20486 {
20489 {
20490 /* First instatiate in template context, in case we still
20491 depend on undeduced template parameters. */
20494 NULL_TREE);
20498 /* We replaced all the tparms, substitute again out of
20499 template context. */
20501 }
20504 NULL_TREE);
20511 else
20513 }
20522 {
20524 /* The position of the first default template argument,
20525 is also the number of non-defaulted arguments in TARGS.
20526 Record that. */
20529 }
20530 }
20534 }
20540 }
20542 /* Subroutine of type_unification_real. Args are like the variables
20543 at the call site. ARG is an overloaded function (or template-id);
20544 we try deducing template args from each of the overloads, and if
20545 only one succeeds, we go with that. Modifies TARGS and returns
20546 true on success. */
20548 static bool
20550 tree targs,
20551 tree parm,
20552 tree arg,
20553 unification_kind_t strict,
20556 {
20563 {
20566 }
20567 else
20571 /* Handle `&x' where `x' is some static or non-static member
20572 function name. */
20578 /* Strip baselink information. */
20583 {
20584 /* If we got some explicit template args, we need to plug them into
20585 the affected templates before we try to unify, in case the
20586 explicit args will completely resolve the templates in question. */
20593 {
20606 {
20611 {
20614 }
20615 }
20618 }
20619 /* If no templates (or more than one) are fully resolved by the
20620 explicit arguments, this template-id is a non-deduced context; it
20621 could still be OK if we deduce all template arguments for the
20622 enclosing call through other arguments. */
20625 }
20628 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20629 -- but the deduction does not succeed because the expression is
20630 not just the function on its own. */
20632 else
20634 {
20639 {
20642 }
20643 }
20645 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20646 to function or pointer to member function argument if the set of
20647 overloaded functions does not contain function templates and at most
20648 one of a set of overloaded functions provides a unique match.
20650 So if we found multiple possibilities, we return success but don't
20651 deduce anything. */
20654 {
20658 {
20663 /* Don't forget explicit template arguments in a pack. */
20667 }
20668 }
20673 }
20675 /* Core DR 115: In contexts where deduction is done and fails, or in
20676 contexts where deduction is not done, if a template argument list is
20677 specified and it, along with any default template arguments, identifies
20678 a single function template specialization, then the template-id is an
20679 lvalue for the function template specialization. */
20681 tree
20683 {
20696 {
20699 }
20701 {
20704 }
20706 {
20709 }
20712 {
20716 /* If we got some explicit template args, we need to plug them into
20717 the affected templates before we try to unify, in case the
20718 explicit args will completely resolve the templates in question. */
20726 {
20739 {
20742 {
20745 }
20747 {
20750 }
20751 }
20752 }
20754 {
20762 {
20763 tree base
20766 }
20770 }
20772 /* There were no good options and at least one bad one, so let the
20773 user know what the problem is. */
20775 }
20777 }
20779 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20780 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20781 different overloads deduce different arguments for a given parm.
20782 ADDR_P is true if the expression for which deduction is being
20783 performed was of the form "& fn" rather than simply "fn".
20785 Returns 1 on success. */
20787 static int
20789 tree orig_targs,
20790 tree targs,
20791 tree parm,
20792 tree arg,
20793 unification_kind_t strict,
20797 {
20799 tree tempargs;
20805 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20806 to function or pointer to member function argument if the set of
20807 overloaded functions does not contain function templates and at most
20808 one of a set of overloaded functions provides a unique match.
20810 So if this is a template, just return success. */
20822 /* We don't copy orig_targs for this because if we have already deduced
20823 some template args from previous args, unify would complain when we
20824 try to deduce a template parameter for the same argument, even though
20825 there isn't really a conflict. */
20832 /* First make sure we didn't deduce anything that conflicts with
20833 explicitly specified args. */
20835 {
20842 /* Since we're unifying against ourselves, we will fill in
20843 template args used in the function parm list with our own
20844 template parms. Discard them. */
20847 {
20848 /* Check that the argument at each index of the deduced argument pack
20849 is equivalent to the corresponding explicitly specified argument.
20850 We may have deduced more arguments than were explicitly specified,
20851 and that's OK. */
20853 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20854 that's wrong if we deduce the same argument pack from multiple
20855 function arguments: it's only incomplete the first time. */
20868 }
20871 }
20874 {
20879 }
20882 }
20884 /* PARM is a template class (perhaps with unbound template
20885 parameters). ARG is a fully instantiated type. If ARG can be
20886 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20887 TARGS are as for unify. */
20889 static tree
20892 {
20893 tree copy_of_targs;
20903 /* We need to make a new template argument vector for the call to
20904 unify. If we used TARGS, we'd clutter it up with the result of
20905 the attempted unification, even if this class didn't work out.
20906 We also don't want to commit ourselves to all the unifications
20907 we've already done, since unification is supposed to be done on
20908 an argument-by-argument basis. In other words, consider the
20909 following pathological case:
20911 template <int I, int J, int K>
20912 struct S {};
20914 template <int I, int J>
20915 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20917 template <int I, int J, int K>
20918 void f(S<I, J, K>, S<I, I, I>);
20920 void g() {
20921 S<0, 0, 0> s0;
20922 S<0, 1, 2> s2;
20924 f(s0, s2);
20925 }
20927 Now, by the time we consider the unification involving `s2', we
20928 already know that we must have `f<0, 0, 0>'. But, even though
20929 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20930 because there are two ways to unify base classes of S<0, 1, 2>
20931 with S<I, I, I>. If we kept the already deduced knowledge, we
20932 would reject the possibility I=1. */
20936 {
20940 }
20942 /* If unification failed, we're done. */
20948 }
20950 /* Given a template type PARM and a class type ARG, find the unique
20951 base type in ARG that is an instance of PARM. We do not examine
20952 ARG itself; only its base-classes. If there is not exactly one
20953 appropriate base class, return NULL_TREE. PARM may be the type of
20954 a partial specialization, as well as a plain template type. Used
20955 by unify. */
20957 static enum template_base_result
20960 {
20962 tree binfo;
20968 {
20969 /* The type could not be completed. */
20972 }
20974 /* Walk in inheritance graph order. The search order is not
20975 important, and this avoids multiple walks of virtual bases. */
20977 {
20982 {
20983 /* If there is more than one satisfactory baseclass, then:
20985 [temp.deduct.call]
20987 If they yield more than one possible deduced A, the type
20988 deduction fails.
20990 applies. */
20992 {
20995 }
20998 }
20999 }
21003 }
21005 /* Returns the level of DECL, which declares a template parameter. */
21007 static int
21009 {
21011 {
21021 }
21023 }
21025 /* Decide whether ARG can be unified with PARM, considering only the
21026 cv-qualifiers of each type, given STRICT as documented for unify.
21027 Returns nonzero iff the unification is OK on that basis. */
21029 static int
21031 {
21037 {
21038 /* Although a CVR qualifier is ignored when being applied to a
21039 substituted template parameter ([8.3.2]/1 for example), that
21040 does not allow us to unify "const T" with "int&" because both
21041 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
21042 It is ok when we're allowing additional CV qualifiers
21043 at the outer level [14.8.2.1]/3,1st bullet. */
21053 }
21064 }
21066 /* Determines the LEVEL and INDEX for the template parameter PARM. */
21067 void
21069 {
21073 {
21076 }
21077 else
21078 {
21081 }
21082 }
21084 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
21085 do { \
21086 if (unify (TP, TA, P, A, S, EP)) \
21087 return 1; \
21088 } while (0)
21090 /* Unifies the remaining arguments in PACKED_ARGS with the pack
21091 expansion at the end of PACKED_PARMS. Returns 0 if the type
21092 deduction succeeds, 1 otherwise. STRICT is the same as in
21093 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
21094 function call argument list. We'll need to adjust the arguments to make them
21095 types. SUBR tells us if this is from a recursive call to
21096 type_unification_real, or for comparing two template argument
21097 lists. */
21099 static int
21103 {
21104 tree parm
21110 /* Add in any args remembered from an earlier partial instantiation. */
21118 /* Determine the parameter packs we will be deducing from the
21119 pattern, and record their current deductions. */
21122 {
21126 /* Only template parameter packs can be deduced, not e.g. function
21127 parameter packs or __bases or __integer_pack. */
21131 /* Determine the index and level of this parameter pack. */
21136 /* Keep track of the parameter packs and their corresponding
21137 argument packs. */
21140 }
21142 /* Loop through all of the arguments that have not yet been
21143 unified and unify each with the pattern. */
21145 {
21146 tree parm;
21150 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21151 or the element of its argument pack at the current index if
21152 this argument was explicitly specified. */
21154 {
21163 {
21166 }
21168 }
21170 /* If we had explicit template arguments, substitute them into the
21171 pattern before deduction. */
21173 {
21174 /* Some arguments might still be unspecified or dependent. */
21182 NULL_TREE);
21187 }
21188 else
21191 /* Unify the pattern with the current argument. */
21193 explain_p))
21196 /* For each parameter pack, collect the deduced value. */
21198 {
21204 }
21205 }
21207 /* Verify that the results of unification with the parameter packs
21208 produce results consistent with what we've seen before, and make
21209 the deduced argument packs available. */
21211 {
21218 /* By default keep the original deduced argument pack.
21219 If necessary, more specific code is going to update the
21220 resulting deduced argument later down in this function. */
21224 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21225 actually deduce anything. */
21233 {
21234 /* If we had fewer function args than explicit template args,
21235 just use the explicits. */
21240 }
21243 {
21244 tree result;
21245 /* Build the deduced *_ARGUMENT_PACK. */
21247 {
21250 }
21251 else
21256 /* Note the deduced argument packs for this parameter
21257 pack. */
21259 }
21263 {
21264 /* We only had the explicitly-provided arguments before, but
21265 now we have a complete set of arguments. */
21271 }
21272 else
21273 {
21279 /* Inconsistent unification of this parameter pack. */
21281 bad_old_arg,
21282 bad_new_arg);
21283 }
21284 }
21287 }
21289 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21290 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21291 parameters and return value are as for unify. */
21293 static int
21297 {
21298 tree parm_max;
21299 tree arg_max;
21303 /* Our representation of array types uses "N - 1" as the
21304 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21305 not an integer constant. We cannot unify arbitrarily
21306 complex expressions, so we eliminate the MINUS_EXPRs
21307 here. */
21311 {
21314 }
21318 {
21319 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21320 trying to unify the type of a variable with the type
21321 of a template parameter. For example:
21323 template <unsigned int N>
21324 void f (char (&) [N]);
21325 int g();
21326 void h(int i) {
21327 char a[g(i)];
21328 f(a);
21329 }
21331 Here, the type of the ARG will be "int [g(i)]", and
21332 may be a SAVE_EXPR, etc. */
21336 }
21338 /* If only one of the bounds used a MINUS_EXPR, compensate
21339 by adding one to the other bound. */
21342 integer_type_node,
21343 parm_max,
21344 integer_one_node);
21347 integer_type_node,
21348 arg_max,
21349 integer_one_node);
21353 }
21355 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21359 static pa_kind_t
21361 {
21370 else
21372 }
21374 /* Deduce the value of template parameters. TPARMS is the (innermost)
21375 set of template parameters to a template. TARGS is the bindings
21376 for those template parameters, as determined thus far; TARGS may
21377 include template arguments for outer levels of template parameters
21378 as well. PARM is a parameter to a template function, or a
21379 subcomponent of that parameter; ARG is the corresponding argument.
21380 This function attempts to match PARM with ARG in a manner
21381 consistent with the existing assignments in TARGS. If more values
21382 are deduced, then TARGS is updated.
21384 Returns 0 if the type deduction succeeds, 1 otherwise. The
21385 parameter STRICT is a bitwise or of the following flags:
21387 UNIFY_ALLOW_NONE:
21388 Require an exact match between PARM and ARG.
21389 UNIFY_ALLOW_MORE_CV_QUAL:
21390 Allow the deduced ARG to be more cv-qualified (by qualification
21391 conversion) than ARG.
21392 UNIFY_ALLOW_LESS_CV_QUAL:
21393 Allow the deduced ARG to be less cv-qualified than ARG.
21394 UNIFY_ALLOW_DERIVED:
21395 Allow the deduced ARG to be a template base class of ARG,
21396 or a pointer to a template base class of the type pointed to by
21397 ARG.
21398 UNIFY_ALLOW_INTEGER:
21399 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21400 case for more information.
21401 UNIFY_ALLOW_OUTER_LEVEL:
21402 This is the outermost level of a deduction. Used to determine validity
21403 of qualification conversions. A valid qualification conversion must
21404 have const qualified pointers leading up to the inner type which
21405 requires additional CV quals, except at the outer level, where const
21406 is not required [conv.qual]. It would be normal to set this flag in
21407 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21408 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21409 This is the outermost level of a deduction, and PARM can be more CV
21410 qualified at this point.
21411 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21412 This is the outermost level of a deduction, and PARM can be less CV
21413 qualified at this point. */
21415 static int
21418 {
21420 tree targ;
21421 tree tparm;
21423 tsubst_flags_t complain = (explain_p
21424 ? tf_warning_or_error
21427 /* I don't think this will do the right thing with respect to types.
21428 But the only case I've seen it in so far has been array bounds, where
21429 signedness is the only information lost, and I think that will be
21430 okay. */
21438 /* We can't deduce anything from this, but we might get all the
21439 template args from other function args. */
21445 /* If PARM uses template parameters, then we can't bail out here,
21446 even if ARG == PARM, since we won't record unifications for the
21447 template parameters. We might need them if we're trying to
21448 figure out which of two things is more specialized. */
21452 /* Handle init lists early, so the rest of the function can assume
21453 we're dealing with a type. */
21455 {
21460 /* Replace T with std::initializer_list<T> for deduction. */
21467 /* We can only deduce from an initializer list argument if the
21468 parameter is std::initializer_list or an array; otherwise this
21469 is a non-deduced context. */
21474 else
21475 {
21477 /* Deduction is defined in terms of a single type, so just punt
21478 on the (bizarre) std::initializer_list<T...>. */
21481 }
21486 /* If ELTTYPE has no deducible template parms, skip deduction from
21488 else
21490 {
21497 {
21501 /* It should only be possible to get here for a call. */
21503 elt_strict |= maybe_adjust_types_for_deduction
21506 }
21509 explain_p);
21510 }
21514 {
21515 /* Also deduce from the length of the initializer list. */
21522 }
21524 /* If the std::initializer_list<T> deduction worked, replace the
21525 deduced A with std::initializer_list<A>. */
21527 {
21532 }
21534 }
21536 /* If parm and arg aren't the same kind of thing (template, type, or
21537 expression), fail early. */
21541 /* Immediately reject some pairs that won't unify because of
21542 cv-qualification mismatches. */
21545 /* It is the elements of the array which hold the cv quals of an array
21546 type, and the elements might be template type parms. We'll check
21547 when we recurse. */
21549 /* We check the cv-qualifiers when unifying with template type
21550 parameters below. We want to allow ARG `const T' to unify with
21551 PARM `T' for example, when computing which of two templates
21552 is more specialized, for example. */
21566 {
21570 /* In a type which contains a nested-name-specifier, template
21571 argument values cannot be deduced for template parameters used
21572 within the nested-name-specifier. */
21584 /* The PARM is not one we're trying to unify. Just check
21585 to see if it matches ARG. */
21586 {
21591 else
21593 }
21600 /* Check for mixed types and values. */
21608 {
21611 {
21612 /* First try to match ARG directly. */
21614 explain_p);
21616 {
21617 /* Otherwise, look for a suitable base of ARG, as below. */
21624 }
21625 }
21626 /* ARG must be constructed from a template class or a template
21627 template parameter. */
21632 /* Deduce arguments T, i from TT<T> or TT<i>. */
21638 /* Fall through to deduce template name. */
21639 }
21643 {
21644 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21646 /* Simple cases: Value already set, does match or doesn't. */
21651 }
21652 else
21653 {
21654 /* If PARM is `const T' and ARG is only `int', we don't have
21655 a match unless we are allowing additional qualification.
21656 If ARG is `const int' and PARM is just `T' that's OK;
21657 that binds `const int' to `T'. */
21662 /* Consider the case where ARG is `const volatile int' and
21663 PARM is `const T'. Then, T should be `volatile int'. */
21664 arg = cp_build_qualified_type_real
21669 /* Simple cases: Value already set, does match or doesn't. */
21675 /* Make sure that ARG is not a variable-sized array. (Note
21676 that were talking about variable-sized arrays (like
21677 `int[n]'), rather than arrays of unknown size (like
21678 `int[]').) We'll get very confused by such a type since
21679 the bound of the array is not constant, and therefore
21680 not mangleable. Besides, such types are not allowed in
21681 ISO C++, so we can do as we please here. We do allow
21682 them for 'auto' deduction, since that isn't ABI-exposed. */
21686 /* Strip typedefs as in convert_template_argument. */
21688 }
21690 /* If ARG is a parameter pack or an expansion, we cannot unify
21691 against it unless PARM is also a parameter pack. */
21696 /* If the argument deduction results is a METHOD_TYPE,
21697 then there is a problem.
21698 METHOD_TYPE doesn't map to any real C++ type the result of
21699 the deduction can not be of that type. */
21713 {
21714 /* The PARM is not one we're trying to unify. Just check
21715 to see if it matches ARG. */
21721 }
21727 {
21731 /* We're deducing from an array bound, the type doesn't matter. */
21737 }
21739 /* [temp.deduct.type] If, in the declaration of a function template
21740 with a non-type template-parameter, the non-type
21741 template-parameter is used in an expression in the function
21742 parameter-list and, if the corresponding template-argument is
21743 deduced, the template-argument type shall match the type of the
21744 template-parameter exactly, except that a template-argument
21745 deduced from an array bound may be of any integral type.
21746 The non-type parameter might use already deduced type parameters. */
21749 /* We don't have enough levels of args to do any substitution. This
21751 else
21752 {
21758 {
21762 }
21763 }
21766 /* Template-parameter dependent expression. Just accept it for now.
21767 It will later be processed in convert_template_argument. */
21768 ;
21774 /* Convert the ARG to the type of PARM; the deduced non-type
21775 template argument must exactly match the types of the
21776 corresponding parameter. */
21779 {
21780 /* We haven't deduced the type of this parameter yet. */
21782 /* We deduce from array bounds in try_array_deduction. */
21784 {
21785 /* Deduce it from the non-type argument. */
21790 }
21791 else
21792 /* Try again later. */
21794 }
21795 else
21798 /* If ARG is a parameter pack or an expansion, we cannot unify
21799 against it unless PARM is also a parameter pack. */
21804 {
21807 }
21812 {
21813 /* A pointer-to-member constant can be unified only with
21814 another constant. */
21818 /* Just unify the class member. It would be useless (and possibly
21819 wrong, depending on the strict flags) to unify also
21820 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21821 arg refer to the same variable, even if through different
21822 classes. For instance:
21824 struct A { int x; };
21825 struct B : A { };
21827 Unification of &A::x and &B::x must succeed. */
21830 }
21833 {
21837 /* [temp.deduct.call]
21839 A can be another pointer or pointer to member type that can
21840 be converted to the deduced A via a qualification
21841 conversion (_conv.qual_).
21843 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21844 This will allow for additional cv-qualification of the
21845 pointed-to types if appropriate. */
21848 /* The derived-to-base conversion only persists through one
21849 level of pointers. */
21854 }
21886 /* We have already checked cv-qualification at the top of the
21887 function. */
21891 /* As far as unification is concerned, this wins. Later checks
21892 will invalidate it if necessary. */
21895 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21896 /* Type INTEGER_CST can come from ordinary constant template args. */
21908 {
21918 /* Check for pack expansions in the parameters. */
21920 {
21922 {
21924 /* We can unify against something with a trailing
21925 parameter pack. */
21927 else
21928 /* [temp.deduct.type]/9: If the template argument list of
21929 P contains a pack expansion that is not the last
21930 template argument, the entire template argument list
21931 is a non-deduced context. */
21933 }
21934 }
21936 /* If we don't have enough arguments to satisfy the parameters
21937 (not counting the pack expression at the end), or we have
21938 too many arguments for a parameter list that doesn't end in
21939 a pack expression, we can't unify. */
21945 /* Unify all of the parameters that precede the (optional)
21946 pack expression. */
21948 {
21953 }
21956 DEDUCE_EXACT,
21959 }
21967 {
21975 }
21980 {
21984 {
21985 /* First, we try to unify the PARM and ARG directly. */
21990 {
21991 /* Fallback to the special case allowed in
21992 [temp.deduct.call]:
21994 If P is a class, and P has the form
21995 template-id, then A can be a derived class of
21996 the deduced A. Likewise, if P is a pointer to
21997 a class of the form template-id, A can be a
21998 pointer to a derived class pointed to by the
21999 deduced A. */
22005 {
22006 /* Don't give the derived diagnostic if we're
22007 already dealing with the same template. */
22008 bool same_template
22014 }
22015 }
22016 }
22020 /* Perhaps PARM is something like S<U> and ARG is S<int>.
22021 Then, we should unify `int' and `U'. */
22023 else
22024 /* There's no chance of unification succeeding. */
22029 }
22036 {
22039 tree a;
22045 /* CV qualifications for methods can never be deduced, they must
22046 match exactly. We need to check them explicitly here,
22047 because type_unification_real treats them as any other
22048 cv-qualified parameter. */
22050 && (!check_cv_quals_for_unify
22078 {
22090 }
22093 }
22096 /* Unify a pointer to member with a pointer to member function, which
22097 deduces the type of the member as a function type. */
22099 {
22100 /* Check top-level cv qualifiers */
22108 /* Determine the type of the function we are unifying against. */
22112 }
22131 /* Matched cases are handled by the ARG == PARM test above. */
22135 /* We might get a variable as a non-type template argument in parm if the
22136 corresponding parameter is type-dependent. Make any necessary
22137 adjustments based on whether arg is a reference. */
22141 {
22146 }
22147 /* Now use the normal expression code to check whether they match. */
22158 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22159 or UNDERLYING_TYPE nodes. */
22163 /* Unification fails if we hit an error node. */
22168 {
22178 }
22179 /* FALLTHRU */
22182 /* An unresolved overload is a nondeduced context. */
22186 expr:
22187 /* We must be looking at an expression. This can happen with
22188 something like:
22190 template <int I>
22191 void foo(S<I>, S<I + 2>);
22193 This is a "nondeduced context":
22195 [deduct.type]
22197 The nondeduced contexts are:
22199 --A type that is a template-id in which one or more of
22200 the template-arguments is an expression that references
22201 a template-parameter.
22203 In these cases, we assume deduction succeeded, but don't
22204 actually infer any unifications. */
22209 else
22211 }
22212 }
22213 #undef RECUR_AND_CHECK_FAILURE
22214 \f
22215 /* Note that DECL can be defined in this translation unit, if
22216 required. */
22218 static void
22220 {
22221 tree clone;
22225 }
22227 /* Called if RESULT is explicitly instantiated, or is a member of an
22228 explicitly instantiated class. */
22230 void
22232 {
22235 /* If this entity has already been written out, it's too late to
22236 make any modifications. */
22240 /* For anonymous namespace we don't need to do anything. */
22242 {
22245 }
22248 /* The TREE_PUBLIC flag for function declarations will have been
22249 set correctly by tsubst. */
22252 /* This might have been set by an earlier implicit instantiation. */
22257 else
22258 {
22261 /* Always make artificials weak. */
22264 /* For WIN32 we also want to put explicit instantiations in
22265 linkonce sections. */
22270 /* If the function has already been instantiated, clear DECL_EXTERNAL,
22271 since start_preparsed_function wouldn't have if we had an earlier
22272 extern explicit instantiation. */
22274 }
22276 /* If EXTERN_P, then this function will not be emitted -- unless
22277 followed by an explicit instantiation, at which point its linkage
22278 will be adjusted. If !EXTERN_P, then this function will be
22279 emitted here. In neither circumstance do we want
22280 import_export_decl to adjust the linkage. */
22282 }
22284 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22285 important template arguments. If any are missing, we check whether
22286 they're important by using error_mark_node for substituting into any
22287 args that were used for partial ordering (the ones between ARGS and END)
22288 and seeing if it bubbles up. */
22290 static bool
22292 {
22297 {
22300 }
22302 {
22306 }
22308 }
22310 /* Given two function templates PAT1 and PAT2, return:
22312 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22313 -1 if PAT2 is more specialized than PAT1.
22314 0 if neither is more specialized.
22316 LEN indicates the number of parameters we should consider
22317 (defaulted parameters should not be considered).
22319 The 1998 std underspecified function template partial ordering, and
22320 DR214 addresses the issue. We take pairs of arguments, one from
22321 each of the templates, and deduce them against each other. One of
22322 the templates will be more specialized if all the *other*
22323 template's arguments deduce against its arguments and at least one
22324 of its arguments *does* *not* deduce against the other template's
22325 corresponding argument. Deduction is done as for class templates.
22326 The arguments used in deduction have reference and top level cv
22327 qualifiers removed. Iff both arguments were originally reference
22328 types *and* deduction succeeds in both directions, an lvalue reference
22329 wins against an rvalue reference and otherwise the template
22330 with the more cv-qualified argument wins for that pairing (if
22331 neither is more cv-qualified, they both are equal). Unlike regular
22332 deduction, after all the arguments have been deduced in this way,
22333 we do *not* verify the deduced template argument values can be
22334 substituted into non-deduced contexts.
22336 The logic can be a bit confusing here, because we look at deduce1 and
22337 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22338 can find template arguments for pat1 to make arg1 look like arg2, that
22339 means that arg2 is at least as specialized as arg1. */
22341 int
22343 {
22356 /* Remove the this parameter from non-static member functions. If
22357 one is a non-static member function and the other is not a static
22358 member function, remove the first parameter from that function
22359 also. This situation occurs for operator functions where we
22360 locate both a member function (with this pointer) and non-member
22361 operator (with explicit first operand). */
22363 {
22368 }
22370 {
22373 {
22374 len--;
22376 }
22377 }
22379 /* If only one is a conversion operator, they are unordered. */
22383 /* Consider the return type for a conversion function */
22385 {
22388 len++;
22389 }
22391 processing_template_decl++;
22397 /* Stop when an ellipsis is seen. */
22399 {
22410 {
22411 /* When both arguments are pack expansions, we need only
22412 unify the patterns themselves. */
22416 /* This is the last comparison we need to do. */
22418 }
22420 /* DR 1847: If a particular P contains no template-parameters that
22421 participate in template argument deduction, that P is not used to
22422 determine the ordering. */
22428 {
22432 }
22435 {
22439 }
22445 {
22451 /* Setup the parameter vector, which contains only ARG1. */
22454 /* Setup the argument vector, which contains the remaining
22455 arguments. */
22464 /* We cannot deduce in the other direction, because ARG1 is
22465 a pack expansion but ARG2 is not. */
22467 }
22469 {
22475 /* Setup the parameter vector, which contains only ARG1. */
22478 /* Setup the argument vector, which contains the remaining
22479 arguments. */
22488 /* We cannot deduce in the other direction, because ARG2 is
22489 a pack expansion but ARG1 is not.*/
22491 }
22493 else
22494 {
22495 /* The normal case, where neither argument is a pack
22496 expansion. */
22503 }
22505 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22506 arg2, then arg2 is not as specialized as arg1. */
22512 /* "If, for a given type, deduction succeeds in both directions
22513 (i.e., the types are identical after the transformations above)
22514 and both P and A were reference types (before being replaced with
22515 the type referred to above):
22516 - if the type from the argument template was an lvalue reference and
22517 the type from the parameter template was not, the argument type is
22518 considered to be more specialized than the other; otherwise,
22519 - if the type from the argument template is more cv-qualified
22520 than the type from the parameter template (as described above),
22521 the argument type is considered to be more specialized than the other;
22522 otherwise,
22523 - neither type is more specialized than the other." */
22526 {
22528 {
22531 else
22533 }
22535 {
22540 }
22541 }
22544 /* We've failed to deduce something in either direction.
22545 These must be unordered. */
22548 next:
22552 /* We have already processed all of the arguments in our
22553 handing of the pack expansion type. */
22558 }
22560 /* "In most cases, all template parameters must have values in order for
22561 deduction to succeed, but for partial ordering purposes a template
22562 parameter may remain without a value provided it is not used in the
22563 types being used for partial ordering."
22565 Thus, if we are missing any of the targs1 we need to substitute into
22566 origs1, then pat2 is not as specialized as pat1. This can happen when
22567 there is a nondeduced context. */
22573 processing_template_decl--;
22575 /* If both deductions succeed, the partial ordering selects the more
22576 constrained template. */
22578 {
22583 }
22585 /* All things being equal, if the next argument is a pack expansion
22586 for one function but not for the other, prefer the
22587 non-variadic function. FIXME this is bogus; see c++/41958. */
22591 {
22594 }
22600 else
22602 }
22604 /* Determine which of two partial specializations of TMPL is more
22605 specialized.
22607 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22608 to the first partial specialization. The TREE_PURPOSE is the
22609 innermost set of template parameters for the partial
22610 specialization. PAT2 is similar, but for the second template.
22612 Return 1 if the first partial specialization is more specialized;
22613 -1 if the second is more specialized; 0 if neither is more
22614 specialized.
22616 See [temp.class.order] for information about determining which of
22617 two templates is more specialized. */
22619 static int
22621 {
22622 tree targs;
22631 /* Just like what happens for functions, if we are ordering between
22632 different template specializations, we may encounter dependent
22633 types in the arguments, and we need our dependency check functions
22634 to behave correctly. */
22638 {
22641 }
22645 {
22648 }
22651 /* If both deductions succeed, the partial ordering selects the more
22652 constrained template. */
22656 /* In the case of a tie where at least one of the templates
22657 has a parameter pack at the end, the template with the most
22658 non-packed parameters wins. */
22660 && any_deductions
22663 {
22669 /* We don't count the pack expansion at the end. */
22679 }
22682 }
22684 /* Return the template arguments that will produce the function signature
22685 DECL from the function template FN, with the explicit template
22686 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22687 also match. Return NULL_TREE if no satisfactory arguments could be
22688 found. */
22690 static tree
22692 {
22696 tree decl_arg_types;
22699 tree arg;
22703 /* Never do unification on the 'this' parameter. */
22725 }
22727 /* Return the innermost template arguments that, when applied to a partial
22728 specialization SPEC_TMPL of TMPL, yield the ARGS.
22730 For example, suppose we have:
22732 template <class T, class U> struct S {};
22733 template <class T> struct S<T*, int> {};
22735 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22736 partial specialization and the ARGS will be {double*, int}. The resulting
22737 vector will be {double}, indicating that `T' is bound to `double'. */
22739 static tree
22741 {
22743 tree spec_args
22746 tree deduced_args;
22747 tree innermost_deduced_args;
22751 {
22755 innermost_deduced_args);
22756 }
22757 else
22761 again:
22770 {
22772 {
22778 }
22780 }
22783 {
22786 }
22788 /* Verify that nondeduced template arguments agree with the type
22789 obtained from argument deduction.
22791 For example:
22793 struct A { typedef int X; };
22794 template <class T, class U> struct C {};
22795 template <class T> struct C<T, typename T::X> {};
22797 Then with the instantiation `C<A, int>', we can deduce that
22798 `T' is `A' but unify () does not check whether `typename T::X'
22799 is `int'. */
22810 /* We only need to check the innermost arguments; the other
22811 arguments will always agree. */
22816 /* Now that we have bindings for all of the template arguments,
22817 ensure that the arguments deduced for the template template
22818 parameters have compatible template parameter lists. See the use
22819 of template_template_parm_bindings_ok_p in fn_type_unification
22820 for more information. */
22825 }
22827 // Compare two function templates T1 and T2 by deducing bindings
22828 // from one against the other. If both deductions succeed, compare
22829 // constraints to see which is more constrained.
22830 static int
22832 {
22837 {
22840 }
22843 {
22846 }
22848 // If both deductions succeed, then one may be more constrained.
22853 }
22855 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22856 Return the TREE_LIST node with the most specialized template, if
22857 any. If there is no most specialized template, the error_mark_node
22858 is returned.
22860 Note that this function does not look at, or modify, the
22861 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22862 returned is one of the elements of INSTANTIATIONS, callers may
22863 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22864 and retrieve it from the value returned. */
22866 tree
22868 {
22875 {
22881 {
22882 /* Equally specialized, move to next function. If there
22883 is no next function, nothing's most specialized. */
22888 }
22889 }
22892 /* Now verify that champ is better than everything earlier in the
22893 instantiation list. */
22896 {
22899 }
22900 }
22902 processing_template_decl--;
22908 }
22910 /* If DECL is a specialization of some template, return the most
22911 general such template. Otherwise, returns NULL_TREE.
22913 For example, given:
22915 template <class T> struct S { template <class U> void f(U); };
22917 if TMPL is `template <class U> void S<int>::f(U)' this will return
22918 the full template. This function will not trace past partial
22919 specializations, however. For example, given in addition:
22921 template <class T> struct S<T*> { template <class U> void f(U); };
22923 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22924 `template <class T> template <class U> S<T*>::f(U)'. */
22926 tree
22928 {
22930 {
22933 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22934 template friend, or a FIELD_DECL for a capture pack. */
22937 }
22939 /* Look for more and more general templates. */
22941 {
22942 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22943 (See cp-tree.h for details.) */
22952 /* Stop if we run into an explicitly specialized class template. */
22959 }
22962 }
22964 /* Return the most specialized of the template partial specializations
22965 which can produce TARGET, a specialization of some class or variable
22966 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22967 a TEMPLATE_DECL node corresponding to the partial specialization, while
22968 the TREE_PURPOSE is the set of template arguments that must be
22969 substituted into the template pattern in order to generate TARGET.
22971 If the choice of partial specialization is ambiguous, a diagnostic
22972 is issued, and the error_mark_node is returned. If there are no
22973 partial specializations matching TARGET, then NULL_TREE is
22974 returned, indicating that the primary template should be used. */
22976 static tree
22978 {
22980 tree t;
22981 tree champ;
22988 {
22992 }
22994 {
22997 }
22999 {
23003 }
23004 else
23009 /* For determining which partial specialization to use, only the
23010 innermost args are interesting. */
23012 {
23015 }
23018 {
23019 tree spec_args;
23023 {
23024 /* Substitute in the template args from the enclosing class. */
23028 }
23035 {
23039 /* Keep the candidate only if the constraints are satisfied,
23040 or if we're not compiling with concepts. */
23043 {
23046 }
23047 }
23048 }
23058 {
23061 ;
23062 else
23063 {
23065 {
23068 {
23071 }
23072 }
23074 }
23075 }
23079 {
23082 {
23085 }
23086 }
23089 {
23096 else
23100 {
23105 }
23108 }
23111 }
23113 /* Explicitly instantiate DECL. */
23115 void
23117 {
23122 /* An error occurred, for which grokdeclarator has already issued
23123 an appropriate message. */
23126 {
23129 }
23131 {
23134 else
23137 }
23143 {
23144 /* There is an asymmetry here in the way VAR_DECLs and
23145 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23146 the latter, the DECL we get back will be marked as a
23147 template instantiation, and the appropriate
23148 DECL_TEMPLATE_INFO will be set up. This does not happen for
23149 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23150 should handle VAR_DECLs as it currently handles
23151 FUNCTION_DECLs. */
23153 {
23156 }
23159 {
23162 }
23164 {
23169 }
23170 }
23172 {
23175 }
23176 else
23179 /* Check for various error cases. Note that if the explicit
23180 instantiation is valid the RESULT will currently be marked as an
23181 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23182 until we get here. */
23185 {
23186 /* DR 259 [temp.spec].
23188 Both an explicit instantiation and a declaration of an explicit
23189 specialization shall not appear in a program unless the explicit
23190 instantiation follows a declaration of the explicit specialization.
23192 For a given set of template parameters, if an explicit
23193 instantiation of a template appears after a declaration of an
23194 explicit specialization for that template, the explicit
23195 instantiation has no effect. */
23197 }
23199 {
23200 /* [temp.spec]
23202 No program shall explicitly instantiate any template more
23203 than once.
23205 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23206 the first instantiation was `extern' and the second is not,
23207 and EXTERN_P for the opposite case. */
23210 /* If an "extern" explicit instantiation follows an ordinary
23211 explicit instantiation, the template is instantiated. */
23214 }
23216 {
23219 }
23221 {
23224 }
23227 ;
23229 {
23232 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23235 }
23236 else
23244 }
23246 static void
23248 {
23254 {
23257 }
23258 }
23260 /* Called from do_type_instantiation through binding_table_foreach to
23261 do recursive instantiation for the type bound in ENTRY. */
23262 static void
23264 {
23271 }
23273 /* Perform an explicit instantiation of template class T. STORAGE, if
23274 non-null, is the RID for extern, inline or static. COMPLAIN is
23275 nonzero if this is called from the parser, zero if called recursively,
23276 since the standard is unclear (as detailed below). */
23278 void
23280 {
23290 {
23291 tree tmpl =
23295 else
23298 }
23303 {
23306 t);
23308 }
23311 {
23313 {
23315 {
23318 "ISO C++ 1998 forbids the use of %<extern%> on "
23320 }
23321 else
23323 "ISO C++ forbids the use of %qE"
23325 }
23333 else
23334 {
23336 storage);
23338 }
23339 }
23342 {
23343 /* DR 259 [temp.spec].
23345 Both an explicit instantiation and a declaration of an explicit
23346 specialization shall not appear in a program unless the explicit
23347 instantiation follows a declaration of the explicit specialization.
23349 For a given set of template parameters, if an explicit
23350 instantiation of a template appears after a declaration of an
23351 explicit specialization for that template, the explicit
23352 instantiation has no effect. */
23354 }
23356 {
23357 /* [temp.spec]
23359 No program shall explicitly instantiate any template more
23360 than once.
23362 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23363 instantiation was `extern'. If EXTERN_P then the second is.
23364 These cases are OK. */
23371 /* If we've already instantiated the template, just return now. */
23374 }
23382 /* In contrast to implicit instantiation, where only the
23383 declarations, and not the definitions, of members are
23384 instantiated, we have here:
23386 [temp.explicit]
23388 The explicit instantiation of a class template specialization
23389 implies the instantiation of all of its members not
23390 previously explicitly specialized in the translation unit
23391 containing the explicit instantiation.
23393 Of course, we can't instantiate member template classes, since we
23394 don't have any arguments for them. Note that the standard is
23395 unclear on whether the instantiation of the members are
23396 *explicit* instantiations or not. However, the most natural
23397 interpretation is that it should be an explicit
23398 instantiation. */
23402 && !static_p
23405 {
23410 }
23415 }
23417 /* Given a function DECL, which is a specialization of TMPL, modify
23418 DECL to be a re-instantiation of TMPL with the same template
23419 arguments. TMPL should be the template into which tsubst'ing
23420 should occur for DECL, not the most general template.
23422 One reason for doing this is a scenario like this:
23424 template <class T>
23425 void f(const T&, int i);
23427 void g() { f(3, 7); }
23429 template <class T>
23430 void f(const T& t, const int i) { }
23432 Note that when the template is first instantiated, with
23433 instantiate_template, the resulting DECL will have no name for the
23434 first parameter, and the wrong type for the second. So, when we go
23435 to instantiate the DECL, we regenerate it. */
23437 static void
23439 {
23440 /* The arguments used to instantiate DECL, from the most general
23441 template. */
23442 tree code_pattern;
23446 /* Make sure that we can see identifiers, and compute access
23447 correctly. */
23451 {
23452 tree decl_parm;
23453 tree pattern_parm;
23454 tree specs;
23468 specs);
23470 /* Merge parameter declarations. */
23473 pattern_parm
23477 {
23478 tree parm_type;
23479 tree attributes;
23484 NULL_TREE);
23490 {
23493 }
23496 }
23497 /* Merge any parameters that match with the function parameter
23498 pack. */
23500 {
23502 tree expanded_types;
23503 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23504 the parameters in this function parameter pack. */
23509 {
23510 tree parm_type;
23511 tree attributes;
23514 /* Rename the parameter to include the index. */
23523 {
23526 }
23528 }
23529 }
23530 /* Merge additional specifiers from the CODE_PATTERN. */
23534 }
23536 {
23546 }
23547 else
23551 }
23553 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23554 substituted to get DECL. */
23556 tree
23558 {
23561 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23562 for the instantiation. This is not always the most general
23563 template. Consider, for example:
23565 template <class T>
23566 struct S { template <class U> void f();
23567 template <> void f<int>(); };
23569 and an instantiation of S<double>::f<int>. We want TD to be the
23570 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23572 more general template. */
23574 /* We must also deal with friend templates. Given:
23576 template <class T> struct S {
23577 template <class U> friend void f() {};
23578 };
23580 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23581 so far as the language is concerned, but that's still
23582 where we get the pattern for the instantiation from. On
23583 other hand, if the definition comes outside the class, say:
23585 template <class T> struct S {
23586 template <class U> friend void f();
23587 };
23588 template <class U> friend void f() {}
23590 we don't need to look any further. That's what the check for
23591 DECL_INITIAL is for. */
23595 {
23596 /* The present template, TD, should not be a definition. If it
23597 were a definition, we should be using it! Note that we
23598 cannot restructure the loop to just keep going until we find
23599 a template with a definition, since that might go too far if
23600 a specialization was declared, but not defined. */
23602 /* Fetch the more general template. */
23604 }
23607 }
23609 /* Returns true if we need to instantiate this template instance even if we
23610 know we aren't going to emit it. */
23612 bool
23614 {
23615 /* We always instantiate inline functions so that we can inline them. An
23616 explicit instantiation declaration prohibits implicit instantiation of
23617 non-inline functions. With high levels of optimization, we would
23618 normally inline non-inline functions -- but we're not allowed to do
23619 that for "extern template" functions. Therefore, we check
23620 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23624 /* And we need to instantiate static data members so that
23625 their initializers are available in integral constant
23626 expressions. */
23629 }
23631 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23632 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23633 error, true otherwise. */
23635 bool
23637 {
23640 /* Don't instantiate a noexcept-specification from template context. */
23656 {
23662 {
23663 /* If hash_set::add returns true, the element was already there. */
23668 fn);
23670 }
23672 {
23687 }
23688 else
23698 }
23701 {
23704 else
23706 }
23709 }
23711 /* We're starting to process the function INST, an instantiation of PATTERN;
23712 add their parameters to local_specializations. */
23714 static void
23716 {
23720 {
23724 }
23726 {
23728 {
23731 }
23732 else
23733 {
23734 /* Register the (value) argument pack as a specialization of
23735 TMPL_PARM, then move on. */
23738 }
23739 }
23741 }
23743 /* Produce the definition of D, a _DECL generated from a template. If
23744 DEFER_OK is true, then we don't have to actually do the
23745 instantiation now; we just have to do it sometime. Normally it is
23746 an error if this is an explicit instantiation but D is undefined.
23747 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23748 instantiated class template. */
23750 tree
23752 {
23754 tree gen_args;
23755 tree args;
23756 tree td;
23757 tree code_pattern;
23758 tree spec;
23759 tree gen_tmpl;
23767 /* This function should only be used to instantiate templates for
23768 functions and static member variables. */
23771 /* A concept is never instantiated. */
23774 /* Variables are never deferred; if instantiation is required, they
23775 are instantiated right away. That allows for better code in the
23776 case that an expression refers to the value of the variable --
23777 if the variable has a constant value the referring expression can
23778 take advantage of that fact. */
23782 /* Don't instantiate cloned functions. Instead, instantiate the
23783 functions they cloned. */
23791 /* D has already been instantiated or explicitly specialized, so
23792 there's nothing for us to do here.
23794 It might seem reasonable to check whether or not D is an explicit
23795 instantiation, and, if so, stop here. But when an explicit
23796 instantiation is deferred until the end of the compilation,
23797 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23798 the instantiation. */
23801 /* Check to see whether we know that this template will be
23802 instantiated in some other file, as with "extern template"
23803 extension. */
23806 /* In general, we do not instantiate such templates. */
23814 /* We should already have the extra args. */
23817 /* And what's in the hash table should match D. */
23821 /* This needs to happen before any tsubsting. */
23827 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23828 for the instantiation. */
23833 {
23834 /* Look up an explicit specialization, if any. */
23838 {
23841 }
23842 }
23846 /* We should never be trying to instantiate a member of a class
23847 template or partial specialization. */
23852 /* In the case of a friend template whose definition is provided
23853 outside the class, we may have too many arguments. Drop the
23854 ones we don't need. The same is true for specializations. */
23855 args = get_innermost_template_args
23859 {
23865 }
23866 else
23867 {
23872 else
23874 }
23876 /* We may be in the middle of deferred access check. Disable it now. */
23879 /* Unless an explicit instantiation directive has already determined
23880 the linkage of D, remember that a definition is available for
23881 this entity. */
23891 /* If D is a member of an explicitly instantiated class template,
23892 and no definition is available, treat it like an implicit
23893 instantiation. */
23896 {
23897 /* Leave linkage flags alone on instantiations with anonymous
23898 visibility. */
23900 {
23903 }
23905 }
23907 /* Defer all other templates, unless we have been explicitly
23908 forbidden from doing so. */
23910 template. */
23911 ! pattern_defined
23912 /* If it's OK to postpone instantiation, do so. */
23913 || defer_ok
23914 /* If this is a static data member that will be defined
23915 elsewhere, we don't want to instantiate the entire data
23916 member, but we do want to instantiate the initializer so that
23917 we can substitute that elsewhere. */
23919 /* Handle here a deleted function too, avoid generating
23920 its body (c++/61080). */
23922 {
23923 /* The definition of the static data member is now required so
23924 we must substitute the initializer. */
23928 {
23929 tree ns;
23930 tree init;
23939 args,
23942 /* If instantiating the initializer involved instantiating this
23943 again, don't call cp_finish_decl twice. */
23945 {
23946 /* Make sure the initializer is still constant, in case of
23947 circular dependency (template/instantiate6.C). */
23948 const_init
23952 LOOKUP_ONLYCONVERTING);
23953 }
23957 }
23959 /* We restore the source position here because it's used by
23960 add_pending_template. */
23966 /* [temp.explicit]
23968 The definition of a non-exported function template, a
23969 non-exported member function template, or a non-exported
23970 member function or static data member of a class template
23971 shall be present in every translation unit in which it is
23972 explicitly instantiated. */
23976 /* If we're in unevaluated context, we just wanted to get the
23977 constant value; this isn't an odr use, so don't queue
23978 a full instantiation. */
23981 /* ??? Historically, we have instantiated inline functions, even
23982 when marked as "extern template". */
23986 }
23987 /* Tell the repository that D is available in this translation unit
23988 -- and see if it is supposed to be instantiated here. */
23990 {
23991 /* In a PCH file, despite the fact that the repository hasn't
23992 requested instantiation in the PCH it is still possible that
23993 an instantiation will be required in a file that includes the
23994 PCH. */
23997 /* Instantiate inline functions so that the inliner can do its
23998 job, even though we'll not be emitting a copy of this
23999 function. */
24002 }
24005 tree fn_context;
24008 /* tsubst_lambda_expr resolved any references to enclosing functions. */
24019 else
24020 {
24025 }
24027 /* Mark D as instantiated so that recursive calls to
24028 instantiate_decl do not try to instantiate it again. */
24031 /* Regenerate the declaration in case the template has been modified
24032 by a subsequent redeclaration. */
24035 /* We already set the file and line above. Reset them now in case
24036 they changed as a result of calling regenerate_decl_from_template. */
24040 {
24041 tree init;
24044 /* Clear out DECL_RTL; whatever was there before may not be right
24045 since we've reset the type of the declaration. */
24049 /* The initializer is placed in DECL_INITIAL by
24050 regenerate_decl_from_template so we don't need to
24051 push/pop_access_scope again here. Pull it out so that
24052 cp_finish_decl can process it. */
24057 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
24058 initializer. That function will defer actual emission until
24059 we have a chance to determine linkage. */
24062 /* Enter the scope of D so that access-checking works correctly. */
24075 }
24079 {
24080 /* Set up the list of local specializations. */
24084 /* Set up context. */
24088 else
24091 /* Some typedefs referenced from within the template code need to be
24092 access checked at template instantiation time, i.e now. These
24093 types were added to the template at parsing time. Let's get those
24094 and perform the access checks then. */
24096 args);
24098 /* Create substitution entries for the parameters. */
24101 /* Substitute into the body of the function. */
24105 else
24106 {
24111 /* Set the current input_location to the end of the function
24112 so that finish_function knows where we are. */
24113 input_location
24116 /* Remember if we saw an infinite loop in the template. */
24117 current_function_infinite_loop
24119 }
24121 /* Finish the function. */
24125 else
24126 {
24129 }
24133 }
24135 /* We're not deferring instantiation any more. */
24140 else
24146 out:
24155 }
24157 /* Run through the list of templates that we wish we could
24158 instantiate, and instantiate any we can. RETRIES is the
24159 number of times we retry pending template instantiation. */
24161 void
24163 {
24167 /* Instantiating templates may trigger vtable generation. This in turn
24168 may require further template instantiations. We place a limit here
24169 to avoid infinite loop. */
24171 {
24175 "template instantiation depth exceeds maximum of %d"
24176 " instantiating %q+D, possibly from virtual table generation"
24180 /* Pretend that we defined it. */
24183 }
24185 do
24186 {
24191 {
24196 {
24198 {
24213 }
24216 }
24217 else
24218 {
24221 {
24222 instantiation
24228 }
24232 }
24235 {
24236 /* If INSTANTIATION has been instantiated, then we don't
24237 need to consider it again in the future. */
24242 }
24243 else
24244 {
24247 }
24250 }
24252 }
24256 }
24258 /* Substitute ARGVEC into T, which is a list of initializers for
24259 either base class or a non-static data member. The TREE_PURPOSEs
24260 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24261 instantiate_decl. */
24263 static tree
24265 {
24270 {
24271 tree decl;
24272 tree init;
24278 {
24279 tree expr;
24280 tree arg;
24282 /* Expand the base class expansion type into separate base
24283 classes. */
24285 tf_warning_or_error,
24286 NULL_TREE);
24290 /* We'll be building separate TREE_LISTs of arguments for
24291 each base. */
24297 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24298 expand each argument in the TREE_VALUE of t. */
24305 /* VOID_TYPE_NODE is used to indicate
24306 value-initialization. */
24307 {
24310 }
24311 else
24312 {
24313 /* Substitute parameter packs into each argument in the
24314 TREE_LIST. */
24317 {
24318 tree expanded_exprs;
24320 /* Expand the argument. */
24322 expanded_exprs
24324 tf_warning_or_error,
24325 NULL_TREE);
24329 /* Prepend each of the expanded expressions to the
24330 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24332 {
24337 }
24338 }
24341 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24342 since we built them backwards. */
24344 {
24347 }
24348 }
24349 }
24352 {
24354 {
24358 }
24359 else
24360 {
24361 tree tmp;
24376 /* If we had an initializer but it instantiated to nothing,
24377 value-initialize the object. This will only occur when
24378 the initializer was a pack expansion where the parameter
24379 packs used in that expansion were of length zero. */
24382 }
24386 {
24388 decl);
24390 }
24391 /* Look for a target constructor. */
24395 {
24398 {
24402 }
24404 }
24407 {
24411 }
24412 }
24413 }
24415 }
24417 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24419 static void
24421 {
24426 else
24428 }
24430 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24431 is the instantiation (which should have been created with
24432 start_enum) and ARGS are the template arguments to use. */
24434 static void
24436 {
24437 tree e;
24443 {
24444 tree value;
24445 tree decl;
24448 /* Note that in a template enum, the TREE_VALUE is the
24449 CONST_DECL, not the corresponding INTEGER_CST. */
24454 /* Give this enumeration constant the correct access. */
24457 /* Actually build the enumerator itself. Here we're assuming that
24458 enumerators can't have dependent attributes. */
24461 }
24471 }
24473 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24474 its type -- but without substituting the innermost set of template
24475 arguments. So, innermost set of template parameters will appear in
24476 the type. */
24478 tree
24480 {
24481 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24483 }
24485 /* Return truthvalue if we're processing a template different from
24486 the last one involved in diagnostics. */
24487 bool
24489 {
24491 }
24493 /* Remember current template involved in diagnostics. */
24494 void
24496 {
24498 }
24502 {
24504 }
24506 /* Return TRUE if current_function_decl is being instantiated, false
24507 otherwise. */
24509 bool
24511 {
24515 }
24517 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24518 type. Return false for ok, true for disallowed. Issue error and
24519 inform messages under control of COMPLAIN. */
24521 static bool
24523 {
24541 /* A bound template template parm could later be instantiated to have a valid
24542 nontype parm type via an alias template. */
24548 {
24551 else
24553 type);
24554 }
24556 }
24558 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24559 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24561 static bool
24563 {
24564 tree scope;
24566 /* [temp.dep.type]
24568 A type is dependent if it is:
24570 -- a template parameter. Template template parameters are types
24571 for us (since TYPE_P holds true for them) so we handle
24572 them here. */
24576 /* -- a qualified-id with a nested-name-specifier which contains a
24577 class-name that names a dependent type or whose unqualified-id
24578 names a dependent type. */
24582 /* An alias template specialization can be dependent even if the
24583 resulting type is not. */
24587 /* -- a cv-qualified type where the cv-unqualified type is
24588 dependent.
24589 No code is necessary for this bullet; the code below handles
24590 cv-qualified types, and we don't want to strip aliases with
24591 TYPE_MAIN_VARIANT because of DR 1558. */
24592 /* -- a compound type constructed from any dependent type. */
24601 {
24602 tree arg_type;
24607 arg_type;
24612 /* A value-dependent noexcept-specifier makes the type dependent. */
24615 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24616 affect overload resolution and treating it as dependent breaks
24617 things. */
24622 }
24623 /* -- an array type constructed from any dependent type or whose
24624 size is specified by a constant expression that is
24625 value-dependent.
24627 We checked for type- and value-dependence of the bounds in
24628 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24630 {
24635 }
24637 /* -- a template-id in which either the template name is a template
24638 parameter ... */
24641 /* ... or any of the template arguments is a dependent type or
24642 an expression that is type-dependent or value-dependent. */
24644 && (any_dependent_template_arguments_p
24648 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24649 dependent; if the argument of the `typeof' expression is not
24650 type-dependent, then it should already been have resolved. */
24656 /* A template argument pack is dependent if any of its packed
24657 arguments are. */
24659 {
24665 }
24667 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24668 be template parameters. */
24675 /* The standard does not specifically mention types that are local
24676 to template functions or local classes, but they should be
24677 considered dependent too. For example:
24679 template <int I> void f() {
24680 enum E { a = I };
24681 S<sizeof (E)> s;
24682 }
24684 The size of `E' cannot be known until the value of `I' has been
24685 determined. Therefore, `E' must be considered dependent. */
24689 /* Don't use type_dependent_expression_p here, as it can lead
24690 to infinite recursion trying to determine whether a lambda
24691 nested in a lambda is dependent (c++/47687). */
24695 && (any_dependent_template_arguments_p
24699 /* Other types are non-dependent. */
24701 }
24703 /* Returns TRUE if TYPE is dependent, in the sense of
24704 [temp.dep.type]. Note that a NULL type is considered dependent. */
24706 bool
24708 {
24709 /* If there are no template parameters in scope, then there can't be
24710 any dependent types. */
24712 {
24713 /* If we are not processing a template, then nobody should be
24714 providing us with a dependent type. */
24718 }
24720 /* If the type is NULL, we have not computed a type for the entity
24721 in question; in that case, the type is dependent. */
24725 /* Erroneous types can be considered non-dependent. */
24729 /* Getting here with global_type_node means we improperly called this
24730 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24733 /* If we have not already computed the appropriate value for TYPE,
24734 do so now. */
24736 {
24739 }
24742 }
24744 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24745 lookup. In other words, a dependent type that is not the current
24746 instantiation. */
24748 bool
24750 {
24753 }
24755 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24756 an unknown base of 'this' (and is therefore instantiation-dependent). */
24758 static bool
24760 {
24777 }
24779 /* T is a SCOPE_REF; return whether we need to consider it
24780 instantiation-dependent so that we can check access at instantiation
24781 time even though we know which member it resolves to. */
24783 static bool
24785 {
24792 else
24794 }
24796 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24797 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24798 expression. */
24800 /* Note that this predicate is not appropriate for general expressions;
24801 only constant expressions (that satisfy potential_constant_expression)
24802 can be tested for value dependence. */
24804 bool
24806 {
24810 /* A type-dependent expression is also value-dependent. */
24815 {
24817 /* A dependent member function of the current instantiation. */
24821 /* A dependent member function of the current instantiation. */
24828 /* A name that has not been looked up -- must be dependent. */
24832 /* A non-type template parm. */
24836 /* A non-type template parm. */
24842 /* A constant with literal type and is initialized
24843 with an expression that is value-dependent. */
24845 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24849 {
24853 }
24862 /* These expressions are value-dependent if the type to which
24863 the cast occurs is dependent or the expression being casted
24864 is value-dependent. */
24865 {
24871 /* A functional cast has a list of operands. */
24874 {
24875 /* If there are no operands, it must be an expression such
24876 as "int()". This should not happen for aggregate types
24877 because it would form non-constant expressions. */
24882 }
24888 }
24893 /* FALLTHRU */
24896 /* A `sizeof' expression is value-dependent if the operand is
24897 type-dependent or is a pack expansion. */
24906 /* An 'encode' expression is value-dependent if the operand is
24907 type-dependent. */
24916 /* All instantiation-dependent expressions should also be considered
24917 value-dependent. */
24925 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24926 is value-dependent. */
24927 {
24936 }
24939 {
24956 }
24967 {
24971 }
24974 /* Treat all requires-expressions as value-dependent so
24975 we don't try to fold them. */
24982 {
24989 {
24991 /* In a call to a constexpr member function, look through the
24992 implicit ADDR_EXPR on the object argument so that it doesn't
24993 cause the call to be considered value-dependent. We also
24994 look through it in potential_constant_expression. */
25001 }
25003 }
25009 {
25011 tree val;
25018 }
25021 /* Treat a GNU statement expression as dependent to avoid crashing
25022 under instantiate_non_dependent_expr; it can't be constant. */
25026 /* A constant expression is value-dependent if any subexpression is
25027 value-dependent. */
25029 {
25036 {
25040 {
25043 /* In some cases, some of the operands may be missing.
25044 (For example, in the case of PREDECREMENT_EXPR, the
25045 amount to increment by may be missing.) That doesn't
25046 make the expression dependent. */
25049 }
25050 }
25054 }
25056 }
25058 /* The expression is not value-dependent. */
25060 }
25062 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
25063 [temp.dep.expr]. Note that an expression with no type is
25064 considered dependent. Other parts of the compiler arrange for an
25065 expression with type-dependent subexpressions to have no type, so
25066 this function doesn't have to be fully recursive. */
25068 bool
25070 {
25079 /* An unresolved name is always dependent. */
25085 /* A fold expression is type-dependent. */
25092 /* Some expression forms are never type-dependent. */
25106 /* The types of these expressions depends only on the type to which
25107 the cast occurs. */
25116 /* The types of these expressions depends only on the type created
25117 by the expression. */
25120 {
25121 /* For NEW_EXPR tree nodes created inside a template, either
25122 the object type itself or a TREE_LIST may appear as the
25123 operand 1. */
25126 /* This is an array type. We need to check array dimensions
25127 as well. */
25129 || value_dependent_expression_p
25131 else
25133 }
25136 {
25140 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25141 contains an identifier associated by name lookup with one or more
25142 declarations declared with a dependent type, or...a
25143 nested-name-specifier or qualified-id that names a member of an
25144 unknown specialization. */
25147 }
25157 {
25158 tree elt;
25162 {
25165 }
25167 }
25169 /* A static data member of the current instantiation with incomplete
25170 array type is type-dependent, as the definition and specializations
25171 can have different bounds. */
25178 /* An array of unknown bound depending on a variadic parameter, eg:
25180 template<typename... Args>
25181 void foo (Args... args)
25182 {
25183 int arr[] = { args... };
25184 }
25186 template<int... vals>
25187 void bar ()
25188 {
25189 int arr[] = { vals... };
25190 }
25192 If the array has no length and has an initializer, it must be that
25193 we couldn't determine its length in cp_complete_array_type because
25194 it is dependent. */
25202 /* A function or variable template-id is type-dependent if it has any
25203 dependent template arguments. */
25207 {
25208 /* Consider the innermost template arguments, since those are the ones
25209 that come from the template-id; the template arguments for the
25210 enclosing class do not make it type-dependent unless they are used in
25211 the type of the decl. */
25213 && (any_dependent_template_arguments_p
25216 }
25218 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25219 type-dependent. Checking this is important for functions with auto return
25220 type, which looks like a dependent type. */
25229 {
25233 }
25235 /* Always dependent, on the number of arguments if nothing else. */
25240 {
25245 {
25251 }
25252 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25257 {
25262 }
25265 {
25272 }
25282 }
25286 /* Dependent type attributes might not have made it from the decl to
25287 the type yet. */
25293 }
25295 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25296 type-dependent if the expression refers to a member of the current
25297 instantiation and the type of the referenced member is dependent, or the
25298 class member access expression refers to a member of an unknown
25299 specialization.
25301 This function returns true if the OBJECT in such a class member access
25302 expression is of an unknown specialization. */
25304 bool
25306 {
25307 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25308 dependent. */
25313 }
25315 /* walk_tree callback function for instantiation_dependent_expression_p,
25316 below. Returns non-zero if a dependent subexpression is found. */
25318 static tree
25321 {
25323 {
25324 /* We don't have to worry about decltype currently because decltype
25325 of an instantiation-dependent expr is a dependent type. This
25326 might change depending on the resolution of DR 1172. */
25329 }
25332 {
25333 /* Don't treat an argument list as dependent just because it has no
25334 TREE_TYPE. */
25343 /* Handle expressions with type operands. */
25348 {
25353 {
25356 else
25357 {
25360 }
25361 }
25363 }
25367 /* In a template, finish_class_member_access_expr creates a
25368 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25369 type-dependent, so that we can check access control at
25370 instantiation time (PR 42277). See also Core issue 1273. */
25377 else
25380 /* Treat statement-expressions as dependent. */
25384 /* Treat requires-expressions as dependent. */
25389 /* Treat calls to function concepts as dependent. */
25395 /* And variable concepts. */
25402 }
25406 else
25408 }
25410 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25411 sense defined by the ABI:
25413 "An expression is instantiation-dependent if it is type-dependent
25414 or value-dependent, or it has a subexpression that is type-dependent
25415 or value-dependent."
25417 Except don't actually check value-dependence for unevaluated expressions,
25418 because in sizeof(i) we don't care about the value of i. Checking
25419 type-dependence will in turn check value-dependence of array bounds/template
25420 arguments as needed. */
25422 bool
25424 {
25425 tree result;
25436 }
25438 /* As above, but also check value-dependence of the expression as a whole. */
25440 bool
25442 {
25445 }
25447 /* Like type_dependent_expression_p, but it also works while not processing
25448 a template definition, i.e. during substitution or mangling. */
25450 bool
25452 {
25458 }
25460 /* Returns TRUE if ARGS contains a type-dependent expression. */
25462 bool
25464 {
25466 tree arg;
25469 {
25472 }
25474 }
25476 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25477 expressions) contains any type-dependent expressions. */
25479 bool
25481 {
25487 }
25489 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25490 expressions) contains any value-dependent expressions. */
25492 bool
25494 {
25500 }
25502 /* Returns TRUE if the ARG (a template argument) is dependent. */
25504 bool
25506 {
25510 /* Assume a template argument that was wrongly written by the user
25511 is dependent. This is consistent with what
25512 any_dependent_template_arguments_p [that calls this function]
25513 does. */
25523 {
25526 /* A member template of a dependent class is not necessarily
25527 type-dependent, but it is a dependent template argument because it
25528 will be a member of an unknown specialization to that template. */
25531 }
25533 {
25537 {
25540 }
25543 }
25546 else
25549 }
25551 /* Returns true if ARGS (a collection of template arguments) contains
25552 any types that require structural equality testing. */
25554 bool
25556 {
25566 {
25569 {
25575 {
25576 /* Look inside the argument pack. */
25579 }
25582 {
25595 }
25596 }
25597 }
25600 }
25602 /* Returns true if ARGS (a collection of template arguments) contains
25603 any dependent arguments. */
25605 bool
25607 {
25617 {
25622 }
25625 }
25627 /* Returns true if ARGS contains any errors. */
25629 bool
25631 {
25639 {
25642 else
25644 }
25650 {
25655 }
25658 }
25660 /* Returns TRUE if the template TMPL is type-dependent. */
25662 bool
25664 {
25666 {
25671 }
25673 /* Template template parameters are dependent. */
25677 /* So are names that have not been looked up. */
25681 }
25683 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25685 bool
25687 {
25690 }
25692 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25693 are dependent. */
25695 bool
25697 {
25704 {
25726 {
25730 }
25734 {
25738 {
25743 }
25744 }
25745 }
25748 }
25750 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25751 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25752 no such TYPE can be found. Note that this function peers inside
25753 uninstantiated templates and therefore should be used only in
25754 extremely limited situations. ONLY_CURRENT_P restricts this
25755 peering to the currently open classes hierarchy (which is required
25756 when comparing types). */
25758 tree
25760 {
25761 tree scope;
25762 tree name;
25763 tree decl;
25765 tree pushed_scope;
25766 tree result;
25771 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25774 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25775 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25776 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25777 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25778 identifier of the TYPENAME_TYPE anymore.
25779 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25780 TYPENAME_TYPE instead, we avoid messing up with a possible
25781 typedef variant case. */
25784 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25785 it first before we can figure out what NAME refers to. */
25787 {
25789 /* Given a class template A with a dependent base with nested type C,
25790 typedef typename A::C::C C will land us here, as trying to resolve
25791 the initial A::C leads to the local C typedef, which leads back to
25792 A::C::C. So we break the recursion now. */
25794 else
25796 }
25797 /* If we don't know what SCOPE refers to, then we cannot resolve the
25798 TYPENAME_TYPE. */
25801 /* If this is a typedef, we don't want to look inside (c++/11987). */
25804 /* If SCOPE isn't the template itself, it will not have a valid
25805 TYPE_FIELDS list. */
25807 /* scope is either the template itself or a compatible instantiation
25808 like X<T>, so look up the name in the original template. */
25810 /* If scope has no fields, it can't be a current instantiation. Check this
25811 before currently_open_class to avoid infinite recursion (71515). */
25814 /* If the SCOPE is not the current instantiation, there's no reason
25815 to look inside it. */
25818 /* Enter the SCOPE so that name lookup will be resolved as if we
25819 were in the class definition. In particular, SCOPE will no
25820 longer be considered a dependent type. */
25822 /* Look up the declaration. */
25824 tf_warning_or_error);
25828 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25829 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25835 {
25839 }
25842 {
25843 /* Obtain the template and the arguments. */
25846 {
25847 /* We get here with a plain identifier because a previous tentative
25848 parse of the nested-name-specifier as part of a ptr-operator saw
25849 ::template X<A>. The use of ::template is necessary in a
25850 ptr-operator, but wrong in a declarator-id.
25852 [temp.names]: In a qualified-id of a declarator-id, the keyword
25853 template shall not appear at the top level. */
25857 }
25859 /* Instantiate the template. */
25865 }
25867 /* Leave the SCOPE. */
25871 /* If we failed to resolve it, return the original typename. */
25875 /* If lookup found a typename type, resolve that too. */
25877 {
25878 /* Ill-formed programs can cause infinite recursion here, so we
25879 must catch that. */
25883 }
25885 /* Qualify the resulting type. */
25891 }
25893 /* EXPR is an expression which is not type-dependent. Return a proxy
25894 for EXPR that can be used to compute the types of larger
25895 expressions containing EXPR. */
25897 tree
25899 {
25901 tree inner_expr;
25903 /* When checking, try to get a constant value for all non-dependent
25904 expressions in order to expose bugs in *_dependent_expression_p
25905 and constexpr. This can affect code generation, see PR70704, so
25906 only do this for -fchecking=2. */
25909 /* Don't do this during nsdmi parsing as it can lead to
25910 unexpected recursive instantiations. */
25912 /* Don't do this during concept expansion either and for
25913 the same reason. */
25919 /* Preserve OVERLOADs; the functions must be available to resolve
25920 types. */
25931 /* There is no need to return a proxy for a variable or enumerator. */
25934 /* Preserve string constants; conversions from string constants to
25935 "char *" are allowed, even though normally a "const char *"
25936 cannot be used to initialize a "char *". */
25939 /* Preserve void and arithmetic constants, as an optimization -- there is no
25940 reason to create a new node. */
25945 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25946 There is at least one place where we want to know that a
25947 particular expression is a throw-expression: when checking a ?:
25948 expression, there are special rules if the second or third
25949 argument is a throw-expression. */
25953 /* Don't wrap an initializer list, we need to be able to look inside. */
25957 /* Don't wrap a dummy object, we need to be able to test for it. */
25976 /* If the type is unknown, it can't really be non-dependent */
25979 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25982 }
25984 /* ARGS is a vector of expressions as arguments to a function call.
25985 Replace the arguments with equivalent non-dependent expressions.
25986 This modifies ARGS in place. */
25988 void
25990 {
25992 tree arg;
25995 {
25999 }
26000 }
26002 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
26003 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
26004 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
26006 static tree
26008 {
26022 }
26024 tree
26026 {
26028 }
26030 tree
26032 {
26034 }
26036 /* Return a C++17 deduction placeholder for class template TMPL. */
26038 tree
26040 {
26044 }
26046 /* True iff T is a C++17 class template deduction placeholder. */
26048 bool
26050 {
26052 }
26054 /* Make a "constrained auto" type-specifier. This is an
26055 auto type with constraints that must be associated after
26056 deduction. The constraint is formed from the given
26057 CONC and its optional sequence of arguments, which are
26058 non-null if written as partial-concept-id. */
26060 tree
26062 {
26065 /* Build the constraint. */
26073 /* Our canonical type depends on the constraint. */
26076 /* Attach the constraint to the type declaration. */
26079 }
26081 /* Given type ARG, return std::initializer_list<ARG>. */
26083 static tree
26085 {
26089 {
26093 "deducing from brace-enclosed initializer list"
26097 }
26103 }
26105 /* Replace auto in TYPE with std::initializer_list<auto>. */
26107 static tree
26109 {
26116 }
26118 /* Hash traits for hashing possibly constrained 'auto'
26119 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
26122 {
26125 };
26127 /* Hash the 'auto' T. */
26129 inline hashval_t
26131 {
26133 /* Matching constrained-type-specifiers denote the same template
26134 parameter, so hash the constraint. */
26136 else
26137 /* But unconstrained autos are all separate, so just hash the pointer. */
26139 }
26141 /* Compare two 'auto's. */
26145 {
26152 /* Two unconstrained autos are distinct. */
26157 }
26159 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26160 constrained) auto, add it to the vector. */
26162 static int
26164 {
26167 {
26168 /* All the autos were built with index 0; fix that up now. */
26172 /* If this is a repeated constrained-type-specifier, use the index we
26173 chose before. */
26175 else
26176 {
26177 /* Otherwise this is new, so use the current count. */
26180 }
26182 }
26184 /* Always keep walking. */
26186 }
26188 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26189 says they can appear anywhere in the type. */
26191 static tree
26193 {
26202 {
26207 }
26210 }
26212 /* The stem for deduction guide names. */
26215 /* Return the name for a deduction guide for class template TMPL. */
26217 tree
26219 {
26230 }
26232 /* True if NAME is the name of a deduction guide. */
26234 bool
26236 {
26241 }
26243 /* True if FN is a deduction guide. */
26245 bool
26247 {
26252 }
26254 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26256 bool
26258 {
26265 }
26267 /* True if FN is a guide generated from a constructor template. */
26269 bool
26271 {
26279 }
26281 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26282 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26283 template parameter types. Note that the handling of template template
26284 parameters relies on current_template_parms being set appropriately for the
26285 new template. */
26287 static tree
26290 {
26296 tree newtype;
26299 {
26306 }
26307 else
26308 {
26311 {
26312 // Substitute once to fix references to other template parameters.
26315 // Now substitute again to reduce the level of the auto.
26318 }
26319 else
26322 }
26324 tree newdecl
26329 tree newidx;
26332 {
26342 {
26347 // First create a copy (ttargs) of tsubst_args with an
26348 // additional level for the template template parameter's own
26349 // template parameters (ttparms).
26350 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26358 // Substitute ttargs into ttparms to fix references to
26359 // other template parameters.
26362 // Now substitute again with args based on tparms, to reduce
26363 // the level of the ttparms.
26366 complain);
26367 // Finally, tack the adjusted parms onto tparms.
26369 current_template_parms);
26371 }
26372 }
26373 else
26374 {
26376 tree newconst
26388 }
26391 }
26393 /* Returns a C++17 class deduction guide template based on the constructor
26394 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26395 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26397 static tree
26399 {
26403 location_t loc;
26407 {
26411 {
26414 }
26415 else
26425 }
26426 else
26427 {
26431 fn_tmpl
26441 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26442 fully specialized args for the enclosing class. Strip those off, as
26443 the deduction guide won't have those template parameters. */
26446 /* Discard the 'this' parameter. */
26454 {
26457 /* For a member template constructor, we need to flatten the two
26458 template parameter lists into one, and then adjust the function
26459 signature accordingly. This gets...complicated. */
26462 /* For a member template we should have two levels of parms/args, one
26463 for the class and one for the constructor. We stripped
26464 specialized args for further enclosing classes above. */
26468 /* Template args for translating references to the two-level template
26469 parameters into references to the one-level template parameters we
26470 are creating. */
26475 /* Template parms for the constructor template. */
26478 /* Template parms for the class template. */
26482 /* Template parms for the deduction guide start as a copy of the
26483 template parms for the class. We set current_template_parms for
26484 lookup_template_class_1. */
26490 /* Now we need to rewrite the constructor parms to append them to the
26491 class parms. */
26493 {
26510 }
26512 /* Now we have a final set of template parms to substitute into the
26513 function signature. */
26522 }
26527 }
26530 {
26531 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26535 }
26539 FUNCTION_DECL,
26556 }
26558 /* Deduce template arguments for the class template placeholder PTYPE for
26559 template TMPL based on the initializer INIT, and return the resulting
26560 type. */
26562 static tree
26564 tsubst_flags_t complain)
26565 {
26567 {
26568 /* We should have handled this in the caller. */
26574 }
26585 {
26588 {
26589 /* As an exception, the first phase in 16.3.1.7 (considering the
26590 initializer list as a single argument) is omitted if the
26591 initializer list consists of a single expression of type cv U,
26592 where U is a specialization of C or a class derived from a
26593 specialization of C. */
26604 }
26607 else
26609 }
26610 else
26621 /* Prune explicit deduction guides in copy-initialization context. */
26623 {
26629 {
26630 /* Found a nonconverting guide, prune the candidates. */
26637 }
26638 }
26643 {
26646 }
26649 // FIXME cache artificial deduction guides
26651 {
26652 /* Skip inherited constructors. */
26662 else
26666 }
26670 /* If this is list-initialization and the class has a list constructor, first
26671 try deducing from the list as a single argument, as [over.match.list]. */
26675 {
26679 }
26681 {
26687 {
26688 /* That didn't work, now try treating the list as a sequence of
26689 arguments. */
26692 }
26693 }
26695 /* Maybe generate an implicit deduction guide. */
26697 {
26701 /* Generate a copy guide. */
26704 /* Generate a default guide. */
26708 {
26713 }
26714 }
26717 {
26719 " of %qT, as it has no non-explicit deduction guides or "
26722 }
26724 {
26728 }
26731 {
26735 }
26738 {
26748 }
26753 }
26755 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26756 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26757 The CONTEXT determines the context in which auto deduction is performed
26758 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26759 OUTER_TARGS are used during template argument deduction
26760 (context == adc_unify) to properly substitute the result, and is ignored
26761 in other contexts.
26763 For partial-concept-ids, extra args may be appended to the list of deduced
26764 template arguments prior to determining constraint satisfaction. */
26766 tree
26770 {
26771 tree targs;
26778 /* Defining a subset of type-dependent expressions that we can deduce
26779 from ahead of time isn't worth the trouble. */
26782 /* Similarly, we can't deduce from another undeduced decl. */
26787 /* C++17 class template argument deduction. */
26791 /* Nothing we can do with this, even in deduction context. */
26794 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26795 with either a new invented type template parameter U or, if the
26796 initializer is a braced-init-list (8.5.4), with
26797 std::initializer_list<U>. */
26799 {
26804 else
26805 {
26807 {
26811 "for deduction to %<std::initializer_list%>, use copy-"
26813 }
26815 }
26816 }
26827 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26828 and initializer has array type, deduce cv-qualified array type. */
26830 complain);
26832 {
26841 {
26845 }
26846 }
26847 else
26848 {
26850 tree tparms;
26854 else
26855 {
26859 }
26863 DEDUCE_CALL,
26866 {
26868 /* Try again at instantiation time. */
26872 /* If type is error_mark_node a diagnostic must have been
26873 emitted by now. Also, having a mention to '<type error>'
26874 in the diagnostic is not really useful to the user. */
26875 {
26879 else
26882 DEDUCE_CALL,
26884 }
26886 }
26887 }
26889 /* Check any placeholder constraints against the deduced type. */
26892 {
26893 /* Use the deduced type to check the associated constraints. If we
26894 have a partial-concept-id, rebuild the argument list so that
26895 we check using the extra arguments. */
26899 {
26902 }
26903 else
26906 {
26908 {
26909 auto_diagnostic_group d;
26911 {
26929 }
26931 }
26933 }
26934 }
26940 }
26942 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26943 result. */
26945 tree
26947 {
26949 {
26955 /* In an abbreviated function template we didn't know we were dealing
26956 with a function template when we saw the auto return type, so update
26957 it to have the correct level. */
26959 }
26961 }
26963 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26964 'decltype(auto)' or a deduced class template. */
26966 bool
26968 {
26974 else
26976 }
26978 /* for_each_template_parm callback for type_uses_auto. */
26980 int
26982 {
26984 }
26986 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26987 a use of `auto'. Returns NULL_TREE otherwise. */
26989 tree
26991 {
26995 {
26996 /* The Concepts TS allows multiple autos in one type-specifier; just
26997 return the first one we find, do_auto_deduction will collect all of
26998 them. */
27002 else
27004 }
27005 else
27007 }
27009 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
27010 concepts are enabled, auto is acceptable in template arguments, but
27011 only when TEMPL identifies a template class. Return TRUE if any
27012 such errors were reported. */
27014 bool
27016 {
27017 /* If there were previous errors, nevermind. */
27021 /* If TMPL is an identifier, we're parsing and we can't tell yet
27022 whether TMPL is supposed to be a type, a function or a variable.
27023 We'll only be able to tell during template substitution, so we
27024 expect to be called again then. If concepts are enabled and we
27025 know we have a type, we're ok. */
27033 /* Quickly search for any occurrences of auto; usually there won't
27034 be any, and then we'll avoid allocating the vector. */
27042 {
27047 }
27050 }
27052 /* For a given template T, return the vector of typedefs referenced
27053 in T for which access check is needed at T instantiation time.
27054 T is either a FUNCTION_DECL or a RECORD_TYPE.
27055 Those typedefs were added to T by the function
27056 append_type_to_template_for_access_check. */
27060 {
27061 tree ti;
27072 {
27077 }
27080 }
27082 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
27083 tied to T. That list of typedefs will be access checked at
27084 T instantiation time.
27085 T is either a FUNCTION_DECL or a RECORD_TYPE.
27086 TYPE_DECL is a TYPE_DECL node representing a typedef.
27087 SCOPE is the scope through which TYPE_DECL is accessed.
27088 LOCATION is the location of the usage point of TYPE_DECL.
27090 This function is a subroutine of
27091 append_type_to_template_for_access_check. */
27093 static void
27095 tree type_decl,
27096 tree scope,
27097 location_t location)
27098 {
27099 qualified_typedef_usage_t typedef_usage;
27100 tree ti;
27107 && type_decl
27121 }
27123 /* Append TYPE_DECL to the template TEMPL.
27124 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
27125 At TEMPL instanciation time, TYPE_DECL will be checked to see
27126 if it can be accessed through SCOPE.
27127 LOCATION is the location of the usage point of TYPE_DECL.
27129 e.g. consider the following code snippet:
27131 class C
27132 {
27133 typedef int myint;
27134 };
27136 template<class U> struct S
27137 {
27138 C::myint mi; // <-- usage point of the typedef C::myint
27139 };
27141 S<char> s;
27143 At S<char> instantiation time, we need to check the access of C::myint
27144 In other words, we need to check the access of the myint typedef through
27145 the C scope. For that purpose, this function will add the myint typedef
27146 and the scope C through which its being accessed to a list of typedefs
27147 tied to the template S. That list will be walked at template instantiation
27148 time and access check performed on each typedefs it contains.
27149 Note that this particular code snippet should yield an error because
27150 myint is private to C. */
27152 void
27154 tree type_decl,
27155 tree scope,
27156 location_t location)
27157 {
27163 /* Make sure we don't append the type to the template twice. */
27170 }
27172 /* Convert the generic type parameters in PARM that match the types given in the
27173 range [START_IDX, END_IDX) from the current_template_parms into generic type
27174 packs. */
27176 tree
27178 {
27189 {
27190 /* Create a distinct parameter pack type from the current parm and add it
27191 to the replacement args to tsubst below into the generic function
27192 parameter. */
27207 }
27213 /* If there are more levels then build up the replacement with the outer
27214 template parms. */
27218 replacement);
27221 }
27223 /* Entries in the decl_constraint hash table. */
27225 {
27226 tree decl;
27227 tree ci;
27228 };
27230 /* Hashing function and equality for constraint entries. */
27232 {
27234 {
27236 }
27239 {
27241 }
27242 };
27244 /* A mapping from declarations to constraint information. Note that
27245 both templates and their underlying declarations are mapped to the
27246 same constraint information.
27248 FIXME: This is defined in pt.c because garbage collection
27249 code is not being generated for constraint.cc. */
27253 /* Returns the template constraints of declaration T. If T is not
27254 constrained, return NULL_TREE. Note that T must be non-null. */
27256 tree
27258 {
27269 else
27271 }
27273 /* Associate the given constraint information CI with the declaration
27274 T. If T is a template, then the constraints are associated with
27275 its underlying declaration. Don't build associations if CI is
27276 NULL_TREE. */
27278 void
27280 {
27292 }
27294 /* Remove the associated constraints of the declaration T. */
27296 void
27298 {
27307 }
27309 /* Memoized satisfaction results for declarations. This
27310 maps the pair (constraint_info, arguments) to the result computed
27311 by constraints_satisfied_p. */
27314 {
27315 tree ci;
27316 tree args;
27317 tree result;
27318 };
27320 /* Hashing function and equality for constraint entries. */
27323 {
27325 {
27328 }
27331 {
27333 }
27334 };
27336 /* Memoized satisfaction results for concept checks. */
27339 {
27340 tree tmpl;
27341 tree args;
27342 tree result;
27343 };
27345 /* Hashing function and equality for constraint entries. */
27348 {
27350 {
27352 }
27355 {
27360 }
27361 };
27366 /* Search for a memoized satisfaction result. Returns one of the
27367 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27369 tree
27371 {
27376 else
27378 }
27380 /* Memoize the result of a satisfication test. Returns the saved result. */
27382 tree
27384 {
27391 }
27393 /* Search for a memoized satisfaction result for a concept. */
27395 tree
27397 {
27402 else
27404 }
27406 /* Memoize the result of a concept check. Returns the saved result. */
27408 tree
27410 {
27417 }
27421 /* Returns a prior concept specialization. This returns the substituted
27422 and normalized constraints defined by the concept. */
27424 tree
27426 {
27431 else
27433 }
27435 /* Save a concept expansion for later. */
27437 tree
27439 {
27446 }
27448 static hashval_t
27450 {
27459 }
27461 /* Compare the constraints of two subsumption entries. The LEFT1 and
27462 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27463 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27465 static bool
27467 {
27475 }
27477 /* Key/value pair for learning and memoizing subsumption results. This
27478 associates a pair of check constraints (including arguments) with
27479 a boolean value indicating the result. */
27482 {
27483 tree t1;
27484 tree t2;
27486 };
27488 /* Hashing function and equality for constraint entries. */
27491 {
27493 {
27495 }
27498 {
27503 }
27504 };
27508 /* Search for a previously cached subsumption result. */
27512 {
27517 else
27519 }
27521 /* Save a subsumption result. */
27523 bool
27525 {
27532 }
27534 /* Set up the hash table for constraint association. */
27536 void
27538 {
27547 }
27549 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27550 0..N-1. */
27552 void
27554 {
27557 integer_type_node,
27558 NULL_TREE),
27564 }
27566 /* Set up the hash tables for template instantiations. */
27568 void
27570 {
27576 }
27578 /* Print stats about the template hash tables for -fstats. */
27580 void
27582 {
27591 }
27593 #if CHECKING_P
27597 /* Verify that build_non_dependent_expr () works, for various expressions,
27598 and that location wrappers don't affect the results. */
27600 static void
27602 {
27605 /* Verify constants, without and with location wrappers. */
27622 }
27624 /* Verify that type_dependent_expression_p () works correctly, even
27625 in the presence of location wrapper nodes. */
27627 static void
27629 {
27634 /* If no templates are involved, nothing is type-dependent. */
27640 /* Within a template, an unresolved name is always type-dependent. */
27643 /* Ensure it copes with NULL_TREE and errors. */
27647 /* A USING_DECL in a template should be type-dependent, even if wrapped
27648 with a location wrapper (PR c++/83799). */
27657 }
27659 /* Run all of the selftests within this file. */
27661 void
27663 {
27666 }