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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2015 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
211 location_t);
218 /* Make the current scope suitable for access checking when we are
219 processing T. T can be FUNCTION_DECL for instantiated function
220 template, VAR_DECL for static member variable, or TYPE_DECL for
221 alias template (needed by instantiate_decl). */
223 static void
225 {
233 else
237 {
238 saved_access_scope = tree_cons
241 }
242 }
244 /* Restore the scope set up by push_access_scope. T is the node we
245 are processing. */
247 static void
249 {
251 {
254 }
258 else
260 }
262 /* Do any processing required when DECL (a member template
263 declaration) is finished. Returns the TEMPLATE_DECL corresponding
264 to DECL, unless it is a specialization, in which case the DECL
265 itself is returned. */
267 tree
269 {
276 {
277 tree type;
285 {
289 }
291 }
295 {
297 {
300 }
301 else
303 }
304 else
308 }
310 /* Create a template info node. */
312 tree
314 {
319 }
321 /* Return the template info node corresponding to T, whatever T is. */
323 tree
325 {
346 }
348 /* Returns the template nesting level of the indicated class TYPE.
350 For example, in:
351 template <class T>
352 struct A
353 {
354 template <class U>
355 struct B {};
356 };
358 A<T>::B<U> has depth two, while A<T> has depth one.
359 Both A<T>::B<int> and A<int>::B<U> have depth one, if
360 they are instantiations, not specializations.
362 This function is guaranteed to return 0 if passed NULL_TREE so
363 that, for example, `template_class_depth (current_class_type)' is
364 always safe. */
366 int
368 {
375 {
381 }
384 }
386 /* Subroutine of maybe_begin_member_template_processing.
387 Returns true if processing DECL needs us to push template parms. */
389 static bool
391 {
397 }
399 /* Subroutine of maybe_begin_member_template_processing.
400 Push the template parms in PARMS, starting from LEVELS steps into the
401 chain, and ending at the beginning, since template parms are listed
402 innermost first. */
404 static void
406 {
414 current_template_parms
420 NULL);
422 {
431 {
438 /* Push the CONST_DECL. */
444 }
445 }
446 }
448 /* Restore the template parameter context for a member template, a
449 friend template defined in a class definition, or a non-template
450 member of template class. */
452 void
454 {
455 tree parms;
460 {
463 /* Disregard full specializations (c++/60999). */
466 }
469 {
474 {
477 }
480 }
482 /* Remember how many levels of template parameters we pushed so that
483 we can pop them later. */
485 }
487 /* Undo the effects of maybe_begin_member_template_processing. */
489 void
491 {
500 {
504 }
505 }
507 /* Return a new template argument vector which contains all of ARGS,
508 but has as its innermost set of arguments the EXTRA_ARGS. */
510 static tree
512 {
513 tree new_args;
531 }
533 /* Like add_to_template_args, but only the outermost ARGS are added to
534 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
535 (EXTRA_ARGS) levels are added. This function is used to combine
536 the template arguments from a partial instantiation with the
537 template arguments used to attain the full instantiation from the
538 partial instantiation. */
540 static tree
542 {
543 tree new_args;
545 /* If there are more levels of EXTRA_ARGS than there are ARGS,
546 something very fishy is going on. */
549 /* If *all* the new arguments will be the EXTRA_ARGS, just return
550 them. */
554 /* For the moment, we make ARGS look like it contains fewer levels. */
559 /* Now, we restore ARGS to its full dimensions. */
563 }
565 /* Return the N levels of innermost template arguments from the ARGS. */
567 tree
569 {
570 tree new_args;
576 /* If N is 1, just return the innermost set of template arguments. */
580 /* If we're not removing anything, just return the arguments we were
581 given. */
587 /* Make a new set of arguments, not containing the outer arguments. */
594 }
596 /* The inverse of get_innermost_template_args: Return all but the innermost
597 EXTRA_LEVELS levels of template arguments from the ARGS. */
599 static tree
601 {
602 tree new_args;
608 /* If N is 1, just return the outermost set of template arguments. */
612 /* If we're not removing anything, just return the arguments we were
613 given. */
618 /* Make a new set of arguments, not containing the inner arguments. */
625 }
627 /* We've got a template header coming up; push to a new level for storing
628 the parms. */
630 void
632 {
633 /* We use a non-tag-transparent scope here, which causes pushtag to
634 put tags in this scope, rather than in the enclosing class or
635 namespace scope. This is the right thing, since we want
636 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
637 global template class, push_template_decl handles putting the
638 TEMPLATE_DECL into top-level scope. For a nested template class,
639 e.g.:
641 template <class T> struct S1 {
642 template <class T> struct S2 {};
643 };
645 pushtag contains special code to call pushdecl_with_scope on the
646 TEMPLATE_DECL for S2. */
652 /* Add a dummy parameter level while we process the parameter list. */
653 current_template_parms
656 current_template_parms);
657 }
659 /* This routine is called when a specialization is declared. If it is
660 invalid to declare a specialization here, an error is reported and
661 false is returned, otherwise this routine will return true. */
663 static bool
665 {
668 /* [temp.expl.spec]
670 An explicit specialization shall be declared in the namespace of
671 which the template is a member, or, for member templates, in the
672 namespace of which the enclosing class or enclosing class
673 template is a member. An explicit specialization of a member
674 function, member class or static data member of a class template
675 shall be declared in the namespace of which the class template
676 is a member. */
678 {
681 }
683 /* [temp.expl.spec]
685 In an explicit specialization declaration for a member of a class
686 template or a member template that appears in namespace scope,
687 the member template and some of its enclosing class templates may
688 remain unspecialized, except that the declaration shall not
689 explicitly specialize a class member template if its enclosing
690 class templates are not explicitly specialized as well. */
692 {
695 }
698 }
700 /* We've just seen template <>. */
702 bool
704 {
708 }
710 /* Called at then end of processing a declaration preceded by
711 template<>. */
713 void
715 {
718 }
720 /* Any template <>'s that we have seen thus far are not referring to a
721 function specialization. */
723 void
725 {
728 }
730 /* We've just seen a template header. If SPECIALIZATION is nonzero,
731 it was of the form template <>. */
733 static void
735 {
737 template_header_count++;
738 }
740 /* We're beginning an explicit instantiation. */
742 void
744 {
747 }
750 void
752 {
755 }
757 /* An explicit specialization or partial specialization of TMPL is being
758 declared. Check that the namespace in which the specialization is
759 occurring is permissible. Returns false iff it is invalid to
760 specialize TMPL in the current namespace. */
762 static bool
764 {
767 /* [tmpl.expl.spec]
769 An explicit specialization shall be declared in the namespace of
770 which the template is a member, or, for member templates, in the
771 namespace of which the enclosing class or enclosing class
772 template is a member. An explicit specialization of a member
773 function, member class or static data member of a class template
774 shall be declared in the namespace of which the class template is
775 a member. */
778 {
781 }
783 /* Same or super-using namespace. */
785 else
786 {
792 }
793 }
795 /* SPEC is an explicit instantiation. Check that it is valid to
796 perform this explicit instantiation in the current namespace. */
798 static void
800 {
801 tree ns;
803 /* DR 275: An explicit instantiation shall appear in an enclosing
804 namespace of its template. */
810 }
812 // Returns the type of a template specialization only if that
813 // specialization needs to be defined. Otherwise (e.g., if the type has
814 // already been defined), the function returns NULL_TREE.
815 static tree
817 {
818 // An implicit instantiation of an incomplete type implies
819 // the definition of a new class template.
820 //
821 // template<typename T>
822 // struct S;
823 //
824 // template<typename T>
825 // struct S<T*>;
826 //
827 // Here, S<T*> is an implicit instantiation of S whose type
828 // is incomplete.
832 // It can also be the case that TYPE is a completed specialization.
833 // Continuing the previous example, suppose we also declare:
834 //
835 // template<typename T>
836 // requires Integral<T>
837 // struct S<T*>;
838 //
839 // Here, S<T*> refers to the specialization S<T*> defined
840 // above. However, we need to differentiate definitions because
841 // we intend to define a new partial specialization. In this case,
842 // we rely on the fact that the constraints are different for
843 // this declaration than that above.
844 //
845 // Note that we also get here for injected class names and
846 // late-parsed template definitions. We must ensure that we
847 // do not create new type declarations for those cases.
849 {
853 // If there are no template parameters, this cannot be a new
854 // partial template specializtion?
858 // The injected-class-name is not a new partial specialization.
862 // If the constraints are not the same as those of the primary
863 // then, we can probably create a new specialization.
867 {
871 }
873 // Also, if there's a pre-existing specialization with matching
874 // constraints, then this also isn't new.
877 {
885 }
887 // Create a new type node (and corresponding type decl)
888 // for the newly declared specialization.
894 /* We only need a separate type node for storing the definition of this
895 partial specialization; uses of S<T*> are unconstrained, so all are
896 equivalent. So keep TYPE_CANONICAL the same. */
899 // Build the corresponding type decl.
905 }
908 }
910 /* The TYPE is being declared. If it is a template type, that means it
911 is a partial specialization. Do appropriate error-checking. */
913 tree
915 {
916 tree context;
921 /* A lambda that appears in specialization context is not itself a
922 specialization. */
927 {
931 }
936 {
941 else
944 }
946 {
947 /* This is for ordinary explicit specialization and partial
948 specialization of a template class such as:
950 template <> class C<int>;
952 or:
954 template <class T> class C<T*>;
956 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
959 {
966 {
971 }
972 }
978 /* Trying to define a specialization either without a template<> header
979 or in an inappropriate place. We've already given an error, so just
980 bail now so we don't actually define the specialization. */
982 }
988 {
989 /* This is for an explicit specialization of member class
990 template according to [temp.expl.spec/18]:
992 template <> template <class U> class C<int>::D;
994 The context `C<int>' must be an implicit instantiation.
995 Otherwise this is just a member class template declared
996 earlier like:
998 template <> class C<int> { template <class U> class D; };
999 template <> template <class U> class C<int>::D;
1001 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1002 while in the second case, `C<int>::D' is a primary template
1003 and `C<T>::D' may not exist. */
1007 {
1008 tree t;
1013 {
1018 }
1020 /* Check for invalid specialization after instantiation:
1022 template <> template <> class C<int>::D<int>;
1023 template <> template <class U> class C<int>::D; */
1027 {
1031 {
1032 /* We already have a full specialization of this partial
1033 instantiation, or a full specialization has been
1034 looked up but not instantiated. Reassign it to the
1035 new member specialization template. */
1036 spec_entry elt;
1048 spec_entry **slot
1053 }
1054 else
1055 /* But if we've had an implicit instantiation, that's a
1056 problem ([temp.expl.spec]/6). */
1059 }
1061 /* Mark TYPE as a specialization. And as a result, we only
1062 have one level of template argument for the innermost
1063 class template. */
1068 }
1069 }
1071 {
1072 /* Someday C++0x may allow for enum template specialization. */
1077 else
1078 {
1081 }
1082 }
1085 }
1087 /* Returns nonzero if we can optimize the retrieval of specializations
1088 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1089 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1093 {
1096 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1097 parameter. */
1099 /* The optimized lookup depends on the fact that the
1100 template arguments for the member function template apply
1101 purely to the containing class, which is not true if the
1102 containing class is an explicit or partial
1103 specialization. */
1107 /* It is possible to have a template that is not a member
1108 template and is not a member of a template class:
1110 template <typename T>
1111 struct S { friend A::f(); };
1113 Here, the friend function is a template, but the context does
1114 not have template information. The optimized lookup relies
1115 on having ARGS be the template arguments for both the class
1116 and the function template. */
1118 }
1120 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1121 gone through coerce_template_parms by now. */
1123 static void
1125 {
1128 {
1131 {
1138 /* Allow typedefs on the type of a non-type argument, since a
1140 else
1142 }
1143 }
1145 }
1147 /* Retrieve the specialization (in the sense of [temp.spec] - a
1148 specialization is either an instantiation or an explicit
1149 specialization) of TMPL for the given template ARGS. If there is
1150 no such specialization, return NULL_TREE. The ARGS are a vector of
1151 arguments, or a vector of vectors of arguments, in the case of
1152 templates with more than one level of parameters.
1154 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1155 then we search for a partial specialization matching ARGS. This
1156 parameter is ignored if TMPL is not a class template.
1158 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1159 result is a NONTYPE_ARGUMENT_PACK. */
1161 static tree
1163 {
1173 /* There should be as many levels of arguments as there are
1174 levels of parameters. */
1184 {
1185 tree class_template;
1186 tree class_specialization;
1188 tree fns;
1191 /* The template arguments actually apply to the containing
1192 class. Find the class specialization with those
1193 arguments. */
1195 class_specialization
1199 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1200 for the specialization. */
1204 /* Iterate through the methods with the indicated name, looking
1205 for the one that has an instance of TMPL. */
1208 {
1211 /* using-declarations can add base methods to the method vec,
1212 and we don't want those here. */
1215 }
1217 }
1218 else
1219 {
1221 spec_entry elt;
1230 else
1238 }
1241 }
1243 /* Like retrieve_specialization, but for local declarations. */
1245 tree
1247 {
1253 }
1255 /* Returns nonzero iff DECL is a specialization of TMPL. */
1257 int
1259 {
1260 tree t;
1263 {
1269 }
1270 else
1271 {
1280 }
1283 }
1285 /* Returns nonzero iff DECL is a specialization of friend declaration
1286 FRIEND_DECL according to [temp.friend]. */
1288 bool
1290 {
1297 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1298 of a template class, we want to check if DECL is a specialization
1299 if this. */
1303 {
1304 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1307 }
1312 /* There is nothing to do if this is not a template friend. */
1319 /* [temp.friend/6]
1320 A member of a class template may be declared to be a friend of a
1321 non-template class. In this case, the corresponding member of
1322 every specialization of the class template is a friend of the
1323 class granting friendship.
1325 For example, given a template friend declaration
1327 template <class T> friend void A<T>::f();
1329 the member function below is considered a friend
1331 template <> struct A<int> {
1332 void f();
1333 };
1335 For this type of template friend, TEMPLATE_DEPTH below will be
1336 nonzero. To determine if DECL is a friend of FRIEND, we first
1337 check if the enclosing class is a specialization of another. */
1344 {
1345 /* Next, we check the members themselves. In order to handle
1346 a few tricky cases, such as when FRIEND_DECL's are
1348 template <class T> friend void A<T>::g(T t);
1349 template <class T> template <T t> friend void A<T>::h();
1351 and DECL's are
1353 void A<int>::g(int);
1354 template <int> void A<int>::h();
1356 we need to figure out ARGS, the template arguments from
1357 the context of DECL. This is required for template substitution
1358 of `T' in the function parameter of `g' and template parameter
1359 of `h' in the above examples. Here ARGS corresponds to `int'. */
1366 {
1368 {
1371 else
1373 current_depth++;
1374 }
1376 }
1379 {
1381 tree friend_type;
1382 tree decl_type;
1383 tree friend_args_type;
1384 tree decl_args_type;
1386 /* Make sure that both DECL and FRIEND_DECL are templates or
1387 non-templates. */
1393 {
1394 /* If both are templates, check template parameter list. */
1395 tree friend_parms
1400 friend_parms))
1404 }
1405 else
1413 /* Check if return types match. */
1417 /* Check if function parameter types match, ignoring the
1418 `this' parameter. */
1427 }
1428 else
1429 {
1430 /* DECL is a TYPE_DECL */
1434 /* Make sure that both DECL and FRIEND_DECL are templates or
1435 non-templates. */
1436 is_template
1443 {
1444 tree friend_parms;
1445 /* If both are templates, check the name of the two
1446 TEMPLATE_DECL's first because is_friend didn't. */
1451 /* Now check template parameter list. */
1452 friend_parms
1455 return comp_template_parms
1457 friend_parms);
1458 }
1459 else
1462 }
1463 }
1465 }
1467 /* Register the specialization SPEC as a specialization of TMPL with
1468 the indicated ARGS. IS_FRIEND indicates whether the specialization
1469 is actually just a friend declaration. Returns SPEC, or an
1470 equivalent prior declaration, if available.
1472 We also store instantiations of field packs in the hash table, even
1473 though they are not themselves templates, to make lookup easier. */
1475 static tree
1477 hashval_t hash)
1478 {
1479 tree fn;
1481 spec_entry elt;
1489 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1490 register it; we want the corresponding TEMPLATE_DECL instead.
1491 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1492 the more obvious `uses_template_parms (spec)' to avoid problems
1493 with default function arguments. In particular, given
1494 something like this:
1496 template <class T> void f(T t1, T t = T())
1498 the default argument expression is not substituted for in an
1499 instantiation unless and until it is actually needed. */
1503 /* We don't put these specializations in the hash table, but we might
1504 want to give an error about a mismatch. */
1506 else
1507 {
1515 slot =
1519 else
1521 }
1523 /* We can sometimes try to re-register a specialization that we've
1524 already got. In particular, regenerate_decl_from_template calls
1525 duplicate_decls which will update the specialization list. But,
1526 we'll still get called again here anyhow. It's more convenient
1527 to simply allow this than to try to prevent it. */
1531 {
1533 {
1536 {
1538 fn);
1540 }
1541 else
1542 {
1543 tree clone;
1544 /* This situation should occur only if the first
1545 specialization is an implicit instantiation, the
1546 second is an explicit specialization, and the
1547 implicit instantiation has not yet been used. That
1548 situation can occur if we have implicitly
1549 instantiated a member function and then specialized
1550 it later.
1552 We can also wind up here if a friend declaration that
1553 looked like an instantiation turns out to be a
1554 specialization:
1556 template <class T> void foo(T);
1557 class S { friend void foo<>(int) };
1558 template <> void foo(int);
1560 We transform the existing DECL in place so that any
1561 pointers to it become pointers to the updated
1562 declaration.
1564 If there was a definition for the template, but not
1565 for the specialization, we want this to look as if
1566 there were no definition, and vice versa. */
1569 /* The call to duplicate_decls will have applied
1570 [temp.expl.spec]:
1572 An explicit specialization of a function template
1573 is inline only if it is explicitly declared to be,
1574 and independently of whether its function template
1575 is.
1577 to the primary function; now copy the inline bits to
1578 the various clones. */
1580 {
1587 }
1591 }
1592 }
1594 {
1596 /* Dup decl failed, but this is a new definition. Set the
1597 line number so any errors match this new
1598 definition. */
1602 }
1603 }
1607 /* A specialization must be declared in the same namespace as the
1608 template it is specializing. */
1614 {
1623 /* If TMPL is a forward declaration of a template function, keep a list
1624 of all specializations in case we need to reassign them to a friend
1625 template later in tsubst_friend_function.
1627 Also keep a list of all variable template instantiations so that
1628 process_partial_specialization can check whether a later partial
1629 specialization would have used it. */
1632 }
1635 }
1637 /* Returns true iff two spec_entry nodes are equivalent. */
1641 bool
1643 {
1650 /* tmpl could be a FIELD_DECL for a capture pack. */
1654 {
1655 /* Partial specializations of a variable template can be distinguished by
1656 constraints. */
1660 }
1664 }
1666 /* Returns a hash for a template TMPL and template arguments ARGS. */
1668 static hashval_t
1670 {
1673 }
1675 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1676 ignoring SPEC. */
1678 hashval_t
1680 {
1682 }
1684 /* Recursively calculate a hash value for a template argument ARG, for use
1685 in the hash tables of template specializations. */
1687 hashval_t
1689 {
1701 /* We can get one of these when re-hashing a previous entry in the middle
1702 of substituting into a pack expansion. Just look through it. */
1711 {
1719 {
1724 }
1746 {
1750 {
1753 }
1755 }
1759 {
1762 }
1773 val = iterative_hash_template_arg
1785 val);
1787 val);
1796 /* A lambda can't appear in a template arg, but don't crash on
1797 erroneous input. */
1809 /* Now hash operands as usual. */
1814 }
1817 {
1820 {
1821 // We want an alias specialization that survived strip_typedefs
1822 // to hash differently from its TYPE_CANONICAL, to avoid hash
1823 // collisions that compare as different in template_args_equal.
1824 // These could be dependent specializations that strip_typedefs
1825 // left alone, or untouched specializations because
1826 // coerce_template_parms returns the unconverted template
1827 // arguments if it sees incomplete argument packs.
1830 }
1833 val);
1836 /* Otherwise just compare the types during lookup. */
1845 {
1850 }
1851 }
1854 }
1856 /* Unregister the specialization SPEC as a specialization of TMPL.
1857 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1858 if the SPEC was listed as a specialization of TMPL.
1860 Note that SPEC has been ggc_freed, so we can't look inside it. */
1862 bool
1864 {
1866 spec_entry elt;
1874 {
1879 }
1882 }
1884 /* Like register_specialization, but for local declarations. We are
1885 registering SPEC, an instantiation of TMPL. */
1887 void
1889 {
1891 }
1893 /* TYPE is a class type. Returns true if TYPE is an explicitly
1894 specialized class. */
1896 bool
1898 {
1902 }
1904 /* Print the list of functions at FNS, going through all the overloads
1905 for each element of the list. Alternatively, FNS can not be a
1906 TREE_LIST, in which case it will be printed together with all the
1907 overloads.
1909 MORE and *STR should respectively be FALSE and NULL when the function
1910 is called from the outside. They are used internally on recursive
1911 calls. print_candidates manages the two parameters and leaves NULL
1912 in *STR when it ends. */
1914 static void
1916 {
1922 {
1926 }
1927 else
1928 {
1931 {
1932 /* Pick the prefix string. */
1934 {
1938 }
1942 }
1945 }
1948 {
1951 }
1952 }
1954 /* Print the list of candidate FNS in an error message. FNS can also
1955 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1957 void
1959 {
1963 }
1965 /* Get a (possibly) constrained template declaration for the
1966 purpose of ordering candidates. */
1967 static tree
1969 {
1975 }
1977 /* Among candidates having the same signature, return the
1978 most constrained or NULL_TREE if there is no best candidate.
1979 If the signatures of candidates vary (e.g., template
1980 specialization vs. member function), then there can be no
1981 most constrained.
1983 Note that we don't compare constraints on the functions
1984 themselves, but rather those of their templates. */
1985 static tree
1987 {
1988 // Try to find the best candidate in a first pass.
1991 {
1998 }
2000 // Verify that the champ is better than previous candidates.
2005 }
2008 }
2011 /* Returns the template (one of the functions given by TEMPLATE_ID)
2012 which can be specialized to match the indicated DECL with the
2013 explicit template args given in TEMPLATE_ID. The DECL may be
2014 NULL_TREE if none is available. In that case, the functions in
2015 TEMPLATE_ID are non-members.
2017 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2018 specialization of a member template.
2020 The TEMPLATE_COUNT is the number of references to qualifying
2021 template classes that appeared in the name of the function. See
2022 check_explicit_specialization for a more accurate description.
2024 TSK indicates what kind of template declaration (if any) is being
2025 declared. TSK_TEMPLATE indicates that the declaration given by
2026 DECL, though a FUNCTION_DECL, has template parameters, and is
2027 therefore a template function.
2029 The template args (those explicitly specified and those deduced)
2030 are output in a newly created vector *TARGS_OUT.
2032 If it is impossible to determine the result, an error message is
2033 issued. The error_mark_node is returned to indicate failure. */
2035 static tree
2037 tree decl,
2041 tmpl_spec_kind tsk)
2042 {
2043 tree fns;
2044 tree targs;
2045 tree explicit_targs;
2048 /* A TREE_LIST of templates of which DECL may be a specialization.
2049 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2050 corresponding TREE_PURPOSE is the set of template arguments that,
2051 when used to instantiate the template, would produce a function
2052 with the signature of DECL. */
2062 /* We shouldn't be specializing a member template of an
2063 unspecialized class template; we already gave an error in
2064 check_specialization_scope, now avoid crashing. */
2067 {
2070 }
2078 /* Check for baselinks. */
2083 {
2086 }
2088 {
2091 }
2093 /* Count the number of template headers specified for this
2094 specialization. */
2104 {
2107 tf_warning_or_error,
2111 }
2113 {
2117 {
2118 tree decl_arg_types;
2119 tree fn_arg_types;
2120 tree insttype;
2122 /* In case of explicit specialization, we need to check if
2123 the number of template headers appearing in the specialization
2124 is correct. This is usually done in check_explicit_specialization,
2125 but the check done there cannot be exhaustive when specializing
2126 member functions. Consider the following code:
2128 template <> void A<int>::f(int);
2129 template <> template <> void A<int>::f(int);
2131 Assuming that A<int> is not itself an explicit specialization
2132 already, the first line specializes "f" which is a non-template
2133 member function, whilst the second line specializes "f" which
2134 is a template member function. So both lines are syntactically
2135 correct, and check_explicit_specialization does not reject
2136 them.
2138 Here, we can do better, as we are matching the specialization
2139 against the declarations. We count the number of template
2140 headers, and we check if they match TEMPLATE_COUNT + 1
2141 (TEMPLATE_COUNT is the number of qualifying template classes,
2142 plus there must be another header for the member template
2143 itself).
2145 Notice that if header_count is zero, this is not a
2146 specialization but rather a template instantiation, so there
2147 is no check we can perform here. */
2151 /* Check that the number of template arguments at the
2152 innermost level for DECL is the same as for FN. */
2160 /* DECL might be a specialization of FN. */
2164 /* For a non-static member function, we need to make sure
2165 that the const qualification is the same. Since
2166 get_bindings does not try to merge the "this" parameter,
2167 we must do the comparison explicitly. */
2173 /* Skip the "this" parameter and, for constructors of
2174 classes with virtual bases, the VTT parameter. A
2175 full specialization of a constructor will have a VTT
2176 parameter, but a template never will. */
2177 decl_arg_types
2179 fn_arg_types
2182 /* Function templates cannot be specializations; there are
2183 no partial specializations of functions. Therefore, if
2184 the type of DECL does not match FN, there is no
2185 match.
2187 Note that it should never be the case that we have both
2188 candidates added here, and for regular member functions
2189 below. */
2191 {
2195 }
2197 /* See whether this function might be a specialization of this
2198 template. Suppress access control because we might be trying
2199 to make this specialization a friend, and we have already done
2200 access control for the declaration of the specialization. */
2206 /* We cannot deduce template arguments that when used to
2207 specialize TMPL will produce DECL. */
2210 /* Remove, from the set of candidates, all those functions
2211 whose constraints are not satisfied. */
2215 // Then, try to form the new function type.
2219 fn_arg_types
2224 /* Save this template, and the arguments deduced. */
2226 }
2228 /* FN is an ordinary member function, and we need a
2229 specialization of a member template. */
2230 ;
2232 /* We can get IDENTIFIER_NODEs here in certain erroneous
2233 cases. */
2234 ;
2236 /* This is just an ordinary non-member function. Nothing can
2237 be a specialization of that. */
2238 ;
2240 /* Cannot specialize functions that are created implicitly. */
2241 ;
2242 else
2243 {
2244 tree decl_arg_types;
2246 /* This is an ordinary member function. However, since
2247 we're here, we can assume its enclosing class is a
2248 template class. For example,
2250 template <typename T> struct S { void f(); };
2251 template <> void S<int>::f() {}
2253 Here, S<int>::f is a non-template, but S<int> is a
2254 template class. If FN has the same type as DECL, we
2255 might be in business. */
2258 /* Its enclosing class is an explicit specialization
2259 of a template class. This is not a candidate. */
2264 /* The return types differ. */
2267 /* Adjust the type of DECL in case FN is a static member. */
2274 decl_arg_types))
2277 // If the deduced arguments do not satisfy the constraints,
2278 // this is not a candidate.
2282 // Add the candidate.
2284 }
2285 }
2288 {
2289 /* We have:
2291 [temp.expl.spec]
2293 It is possible for a specialization with a given function
2294 signature to be instantiated from more than one function
2295 template. In such cases, explicit specification of the
2296 template arguments must be used to uniquely identify the
2297 function template specialization being specialized.
2299 Note that here, there's no suggestion that we're supposed to
2300 determine which of the candidate templates is most
2301 specialized. However, we, also have:
2303 [temp.func.order]
2305 Partial ordering of overloaded function template
2306 declarations is used in the following contexts to select
2307 the function template to which a function template
2308 specialization refers:
2310 -- when an explicit specialization refers to a function
2311 template.
2313 So, we do use the partial ordering rules, at least for now.
2314 This extension can only serve to make invalid programs valid,
2315 so it's safe. And, there is strong anecdotal evidence that
2316 the committee intended the partial ordering rules to apply;
2317 the EDG front end has that behavior, and John Spicer claims
2318 that the committee simply forgot to delete the wording in
2319 [temp.expl.spec]. */
2322 {
2325 }
2326 }
2328 // Concepts allows multiple declarations of member functions
2329 // with the same signature. Like above, we need to rely on
2330 // on the partial ordering of those candidates to determine which
2331 // is the best.
2333 {
2335 {
2338 }
2339 }
2342 {
2349 else
2352 }
2356 {
2362 }
2364 /* We have one, and exactly one, match. */
2366 {
2370 // Propagate the candidate's constraints to the declaration.
2373 /* DECL is a re-declaration or partial instantiation of a template
2374 function. */
2377 /* It was a specialization of an ordinary member function in a
2378 template class. */
2380 }
2382 /* It was a specialization of a template. */
2385 {
2390 }
2391 else
2394 }
2396 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2397 but with the default argument values filled in from those in the
2398 TMPL_TYPES. */
2400 static tree
2402 tree tmpl_types)
2403 {
2404 tree new_spec_types;
2412 /* Substitute into the rest of the list. */
2413 new_spec_types =
2417 /* Add the default argument for this parameter. */
2420 new_spec_types);
2421 }
2423 /* DECL is an explicit specialization. Replicate default arguments
2424 from the template it specializes. (That way, code like:
2426 template <class T> void f(T = 3);
2427 template <> void f(double);
2428 void g () { f (); }
2430 works, as required.) An alternative approach would be to look up
2431 the correct default arguments at the call-site, but this approach
2432 is consistent with how implicit instantiations are handled. */
2434 static void
2436 {
2437 tree tmpl;
2438 tree spec_types;
2439 tree tmpl_types;
2440 tree new_spec_types;
2441 tree old_type;
2442 tree new_type;
2443 tree t;
2448 /* See if there's anything we need to do. */
2461 {
2462 /* Remove the this pointer, but remember the object's type for
2463 CV quals. */
2469 {
2470 /* DECL may contain more parameters than TMPL due to the extra
2471 in-charge parameter in constructors and destructors. */
2474 }
2476 {
2479 }
2480 }
2482 /* Compute the merged default arguments. */
2483 new_spec_types =
2486 /* Compute the new FUNCTION_TYPE. */
2488 {
2492 new_spec_types);
2495 /* Put the in-charge parameter back. */
2498 new_spec_types);
2502 new_spec_types);
2503 }
2504 else
2506 new_spec_types);
2516 }
2518 /* Return the number of template headers we expect to see for a definition
2519 or specialization of CTYPE or one of its non-template members. */
2521 int
2523 {
2527 {
2528 /* You're supposed to have one `template <...>' for every
2529 template class, but you don't need one for a full
2530 specialization. For example:
2532 template <class T> struct S{};
2533 template <> struct S<int> { void f(); };
2534 void S<int>::f () {}
2536 is correct; there shouldn't be a `template <>' for the
2537 definition of `S<int>::f'. */
2539 /* If CTYPE does not have template information of any
2540 kind, then it is not a template, nor is it nested
2541 within a template. */
2549 }
2552 }
2554 /* Do a simple sanity check on the template headers that precede the
2555 variable declaration DECL. */
2557 void
2559 {
2564 {
2567 "variable templates only available with "
2570 // Namespace-scope variable templates should have a template header.
2572 }
2574 {
2581 "members of an explicitly specialized class are defined "
2583 }
2584 }
2586 /* Check to see if the function just declared, as indicated in
2587 DECLARATOR, and in DECL, is a specialization of a function
2588 template. We may also discover that the declaration is an explicit
2589 instantiation at this point.
2591 Returns DECL, or an equivalent declaration that should be used
2592 instead if all goes well. Issues an error message if something is
2593 amiss. Returns error_mark_node if the error is not easily
2594 recoverable.
2596 FLAGS is a bitmask consisting of the following flags:
2598 2: The function has a definition.
2599 4: The function is a friend.
2601 The TEMPLATE_COUNT is the number of references to qualifying
2602 template classes that appeared in the name of the function. For
2603 example, in
2605 template <class T> struct S { void f(); };
2606 void S<int>::f();
2608 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2609 classes are not counted in the TEMPLATE_COUNT, so that in
2611 template <class T> struct S {};
2612 template <> struct S<int> { void f(); }
2613 template <> void S<int>::f();
2615 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2616 invalid; there should be no template <>.)
2618 If the function is a specialization, it is marked as such via
2619 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2620 is set up correctly, and it is added to the list of specializations
2621 for that template. */
2623 tree
2625 tree decl,
2628 {
2637 tmpl_spec_kind tsk;
2640 {
2643 else
2645 }
2646 else
2650 {
2653 {
2656 }
2658 {
2660 /* This could be something like:
2662 template <class T> void f(T);
2663 class S { friend void f<>(int); } */
2665 else
2666 {
2667 /* This case handles bogus declarations like template <>
2668 template <class T> void f<int>(); */
2671 declarator);
2673 }
2674 }
2678 /* The error has already been reported in
2679 check_specialization_scope. */
2685 /* Fall through. */
2698 decl);
2701 else
2705 /* Fall through. */
2711 /* In cases like template<> constexpr bool v = true;
2712 We'll give an error in check_template_variable. */
2718 else
2724 {
2725 /* This case handles bogus declarations like template <>
2726 template <class T> void f<int>(); */
2730 declarator);
2732 {
2733 /* Partial specialization of variable template. */
2737 }
2741 else
2745 ok:;
2746 }
2749 /* This is a specialization of a member template, without
2750 specialization the containing class. Something like:
2752 template <class T> struct S {
2753 template <class U> void f (U);
2754 };
2755 template <> template <class U> void S<int>::f(U) {}
2757 That's a specialization -- but of the entire template. */
2763 }
2766 /* This doesn't apply to variable templates. */
2769 {
2773 {
2777 }
2778 }
2781 {
2786 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2788 {
2789 tree fns;
2794 else
2795 {
2796 /* If there is no class context, the explicit instantiation
2797 must be at namespace scope. */
2800 /* Find the namespace binding, using the declaration
2801 context. */
2805 {
2808 }
2809 }
2812 }
2818 {
2820 /* A specialization in class scope. This is invalid,
2821 but the error will already have been flagged by
2822 check_specialization_scope. */
2824 else
2825 {
2826 /* It's not valid to write an explicit instantiation in
2827 class scope, e.g.:
2829 class C { template void f(); }
2831 This case is caught by the parser. However, on
2832 something like:
2834 template class C { void f(); };
2836 (which is invalid) we can get here. The error will be
2837 issued later. */
2838 ;
2839 }
2842 }
2845 {
2846 // We'll match variable templates in start_decl.
2850 /* Find the list of functions in ctype that have the same
2851 name as the declared function. */
2857 {
2862 {
2863 /* From [temp.expl.spec]:
2865 If such an explicit specialization for the member
2866 of a class template names an implicitly-declared
2867 special member function (clause _special_), the
2868 program is ill-formed.
2870 Similar language is found in [temp.explicit]. */
2873 }
2876 }
2879 {
2883 }
2884 else
2885 {
2887 tree ovl;
2889 /* For a type-conversion operator, we cannot do a
2890 name-based lookup. We might be looking for `operator
2891 int' which will be a specialization of `operator T'.
2892 So, we find *all* the conversion operators, and then
2893 select from them. */
2901 {
2903 /* There are no more conversion functions. */
2906 /* Glue all these conversion functions together
2907 with those we already have. */
2910 }
2911 }
2914 {
2917 }
2918 else
2920 }
2922 /* Figure out what exactly is being specialized at this point.
2923 Note that for an explicit instantiation, even one for a
2924 member function, we cannot tell apriori whether the
2925 instantiation is for a member template, or just a member
2926 function of a template class. Even if a member template is
2927 being instantiated, the member template arguments may be
2928 elided if they can be deduced from the rest of the
2929 declaration. */
2932 member_specialization,
2933 template_count,
2934 tsk);
2937 /* We couldn't figure out what this declaration was
2938 specializing. */
2940 else
2941 {
2953 {
2954 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2955 is done by do_decl_instantiation later. */
2961 {
2962 /* If TMPL is not the most general template (for
2963 example, if TMPL is a friend template that is
2964 injected into namespace scope), then there will
2965 be too many levels of TARGS. Remove some of them
2966 here. */
2968 tree new_targs;
2975 }
2978 }
2980 /* If we thought that the DECL was a member function, but it
2981 turns out to be specializing a static member function,
2982 make DECL a static member function as well. */
2988 /* If this is a specialization of a member template of a
2989 template class, we want to return the TEMPLATE_DECL, not
2990 the specialization of it. */
2992 {
2997 {
2998 tree parm;
3002 /* We want to use the argument list specified in the
3003 definition, not in the original declaration. */
3008 }
3011 }
3013 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3019 /* Inherit default function arguments from the template
3020 DECL is specializing. */
3024 /* This specialization has the same protection as the
3025 template it specializes. */
3029 /* 7.1.1-1 [dcl.stc]
3031 A storage-class-specifier shall not be specified in an
3032 explicit specialization...
3034 The parser rejects these, so unless action is taken here,
3035 explicit function specializations will always appear with
3036 global linkage.
3038 The action recommended by the C++ CWG in response to C++
3039 defect report 605 is to make the storage class and linkage
3040 of the explicit specialization match the templated function:
3042 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3043 */
3045 {
3049 /* A concept cannot be specialized. */
3051 {
3053 gen_tmpl);
3055 }
3057 /* This specialization has the same linkage and visibility as
3058 the function template it specializes. */
3061 {
3064 }
3067 {
3070 }
3071 }
3073 /* If DECL is a friend declaration, declared using an
3074 unqualified name, the namespace associated with DECL may
3075 have been set incorrectly. For example, in:
3077 template <typename T> void f(T);
3078 namespace N {
3079 struct S { friend void f<int>(int); }
3080 }
3082 we will have set the DECL_CONTEXT for the friend
3083 declaration to N, rather than to the global namespace. */
3088 /* This is not really a declaration of a specialization.
3089 It's just the name of an instantiation. But, it's not
3090 a request for an instantiation, either. */
3093 /* A specialization is not necessarily COMDAT. */
3099 /* If this is a full specialization, register it so that we can find
3100 it again. Partial specializations will be registered in
3101 process_partial_specialization. */
3106 /* A 'structor should already have clones. */
3112 }
3113 }
3116 }
3118 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3119 parameters. These are represented in the same format used for
3120 DECL_TEMPLATE_PARMS. */
3122 int
3124 {
3125 const_tree p1;
3126 const_tree p2;
3134 {
3146 {
3150 /* If either of the template parameters are invalid, assume
3151 they match for the sake of error recovery. */
3164 }
3165 }
3168 /* One set of parameters has more parameters lists than the
3169 other. */
3173 }
3175 /* Determine whether PARM is a parameter pack. */
3177 bool
3179 {
3180 /* Determine if we have a non-type template parameter pack. */
3187 /* If this is a list of template parameters, we could get a
3188 TYPE_DECL or a TEMPLATE_DECL. */
3192 /* Otherwise it must be a type template parameter. */
3196 }
3198 /* Determine if T is a function parameter pack. */
3200 bool
3202 {
3206 }
3208 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3209 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3211 tree
3213 {
3220 }
3222 /* Return true iff the function parameter PARAM_DECL was expanded
3223 from the function parameter pack PACK. */
3225 bool
3227 {
3232 /* The parameter pack and its pack arguments have the same
3233 DECL_PARM_INDEX. */
3235 }
3237 /* Determine whether ARGS describes a variadic template args list,
3238 i.e., one that is terminated by a template argument pack. */
3240 static bool
3242 {
3244 tree last_parm;
3258 }
3260 /* Generate a new name for the parameter pack name NAME (an
3261 IDENTIFIER_NODE) that incorporates its */
3263 static tree
3265 {
3266 /* Munge the name to include the parameter index. */
3267 #define NUMBUF_LEN 128
3281 }
3283 /* Return true if T is a primary function, class or alias template
3284 instantiation. */
3286 bool
3288 {
3302 }
3304 /* Return true if PARM is a template template parameter. */
3306 bool
3308 {
3310 }
3312 /* Return true iff PARM is a DECL representing a type template
3313 parameter. */
3315 bool
3317 {
3322 }
3324 /* Return the template parameters of T if T is a
3325 primary template instantiation, NULL otherwise. */
3327 tree
3329 {
3334 parms = INNERMOST_TEMPLATE_PARMS
3338 }
3340 /* Return the template parameters of the LEVELth level from the full list
3341 of template parameters PARMS. */
3343 tree
3345 {
3346 tree p;
3357 }
3359 /* Returns the template arguments of T if T is a template instantiation,
3360 NULL otherwise. */
3362 tree
3364 {
3372 }
3374 /* Return the argument pack elements of T if T is a template argument pack,
3375 NULL otherwise. */
3377 tree
3379 {
3385 }
3387 /* Structure used to track the progress of find_parameter_packs_r. */
3388 struct find_parameter_pack_data
3389 {
3390 /* TREE_LIST that will contain all of the parameter packs found by
3391 the traversal. */
3394 /* Set of AST nodes that have been visited by the traversal. */
3397 /* True iff we're making a type pack expansion. */
3399 };
3401 /* Identifies all of the argument packs that occur in a template
3402 argument and appends them to the TREE_LIST inside DATA, which is a
3403 find_parameter_pack_data structure. This is a subroutine of
3404 make_pack_expansion and uses_parameter_packs. */
3405 static tree
3407 {
3413 /* Handle type aliases/typedefs. */
3415 {
3422 }
3424 /* Identify whether this is a parameter pack or not. */
3426 {
3435 /* If the placeholder appears in the decl-specifier-seq of a function
3436 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3437 is a pack expansion, the invented template parameter is a template
3438 parameter pack. */
3448 {
3449 /* We don't want to walk into the type of a PARM_DECL,
3450 because we don't want to see the type parameter pack. */
3453 }
3456 /* Look through a lambda capture proxy to the field pack. */
3459 {
3465 }
3467 {
3469 find_parameter_packs_r,
3472 }
3479 /* Not a parameter pack. */
3481 }
3484 {
3485 /* Add this parameter pack to the list. */
3487 }
3493 /* This switch statement will return immediately if we don't find a
3494 parameter pack. */
3496 {
3501 /* Check the template itself. */
3504 /* Check the template arguments. */
3520 /* Fall through. */
3561 {
3562 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3563 type_pack_expansion_p to false so that any placeholders
3564 within the expression don't get marked as parameter packs. */
3572 }
3576 }
3579 }
3581 /* Determines if the expression or type T uses any parameter packs. */
3582 bool
3584 {
3593 }
3595 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3596 representation a base-class initializer into a parameter pack
3597 expansion. If all goes well, the resulting node will be an
3598 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3599 respectively. */
3600 tree
3602 {
3603 tree result;
3612 {
3613 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3614 class initializer. In this case, the TREE_PURPOSE will be a
3615 _TYPE node (representing the base class expansion we're
3616 initializing) and the TREE_VALUE will be a TREE_LIST
3617 containing the initialization arguments.
3619 The resulting expansion looks somewhat different from most
3620 expansions. Rather than returning just one _EXPANSION, we
3621 return a TREE_LIST whose TREE_PURPOSE is a
3622 TYPE_PACK_EXPANSION containing the bases that will be
3623 initialized. The TREE_VALUE will be identical to the
3624 original TREE_VALUE, which is a list of arguments that will
3625 be passed to each base. We do not introduce any new pack
3626 expansion nodes into the TREE_VALUE (although it is possible
3627 that some already exist), because the TREE_PURPOSE and
3628 TREE_VALUE all need to be expanded together with the same
3629 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3630 resulting TREE_PURPOSE will mention the parameter packs in
3631 both the bases and the arguments to the bases. */
3632 tree purpose;
3633 tree value;
3636 /* Determine which parameter packs will be used by the base
3637 class expansion. */
3644 {
3648 }
3651 {
3652 /* Collect the sets of parameter packs used in each of the
3653 initialization arguments. */
3655 {
3656 /* Determine which parameter packs will be expanded in this
3657 argument. */
3660 }
3661 }
3665 /* Create the pack expansion type for the base type. */
3670 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3671 they will rarely be compared to anything. */
3675 }
3680 /* Build the PACK_EXPANSION_* node. */
3681 result = for_types
3686 {
3687 /* Propagate type and const-expression information. */
3690 }
3691 else
3692 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3693 they will rarely be compared to anything. */
3696 /* Determine which parameter packs will be expanded. */
3703 /* Make sure we found some parameter packs. */
3705 {
3708 else
3711 }
3717 }
3719 /* Checks T for any "bare" parameter packs, which have not yet been
3720 expanded, and issues an error if any are found. This operation can
3721 only be done on full expressions or types (e.g., an expression
3722 statement, "if" condition, etc.), because we could have expressions like:
3724 foo(f(g(h(args)))...)
3726 where "args" is a parameter pack. check_for_bare_parameter_packs
3727 should not be called for the subexpressions args, h(args),
3728 g(h(args)), or f(g(h(args))), because we would produce erroneous
3729 error messages.
3731 Returns TRUE and emits an error if there were bare parameter packs,
3732 returns FALSE otherwise. */
3733 bool
3735 {
3752 {
3755 {
3764 else
3769 else
3773 }
3776 }
3779 }
3781 /* Expand any parameter packs that occur in the template arguments in
3782 ARGS. */
3783 tree
3785 {
3791 /* First, determine if we need to expand anything, and the number of
3792 slots we'll need. */
3794 {
3799 {
3803 else
3805 }
3806 else
3807 {
3809 num_result_args++;
3810 }
3811 }
3813 /* If no expansion is necessary, we're done. */
3817 /* Expand arguments. */
3820 non_default_args_count =
3823 {
3826 {
3833 }
3834 else
3835 {
3838 }
3839 }
3843 }
3845 /* Checks if DECL shadows a template parameter.
3847 [temp.local]: A template-parameter shall not be redeclared within its
3848 scope (including nested scopes).
3850 Emits an error and returns TRUE if the DECL shadows a parameter,
3851 returns FALSE otherwise. */
3853 bool
3855 {
3856 tree olddecl;
3858 /* If we're not in a template, we can't possibly shadow a template
3859 parameter. */
3863 /* Figure out what we're shadowing. */
3868 /* If there's no previous binding for this name, we're not shadowing
3869 anything, let alone a template parameter. */
3873 /* If we're not shadowing a template parameter, we're done. Note
3874 that OLDDECL might be an OVERLOAD (or perhaps even an
3875 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3876 node. */
3880 /* We check for decl != olddecl to avoid bogus errors for using a
3881 name inside a class. We check TPFI to avoid duplicate errors for
3882 inline member templates. */
3888 /* Don't complain about the injected class name, as we've already
3889 complained about the class itself. */
3896 else
3901 }
3903 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3904 ORIG_LEVEL, DECL, and TYPE. */
3906 static tree
3910 tree decl,
3911 tree type)
3912 {
3923 }
3925 /* Find the canonical type parameter for the given template type
3926 parameter. Returns the canonical type parameter, which may be TYPE
3927 if no such parameter existed. */
3929 static tree
3931 {
3932 tree list;
3946 else
3947 {
3952 }
3953 }
3955 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3956 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3957 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3958 new one is created. */
3960 static tree
3962 tsubst_flags_t complain)
3963 {
3968 {
3987 /* Template template parameters need this. */
3989 {
3996 }
3997 }
4000 }
4002 /* Process information from new template parameter PARM and append it
4003 to the LIST being built. This new parameter is a non-type
4004 parameter iff IS_NON_TYPE is true. This new parameter is a
4005 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4006 is in PARM_LOC. */
4008 tree
4011 {
4020 {
4024 {
4028 else
4030 }
4033 }
4036 {
4042 {
4043 /* [temp.param]
4045 The top-level cv-qualifiers on the template-parameter are
4046 ignored when determining its type. */
4051 && !is_parameter_pack
4052 /* If we're in a nested template parameter list, the template
4053 template parameter could be a parameter pack. */
4055 {
4056 /* This template parameter is not a parameter pack, but it
4057 should be. Complain about "bare" parameter packs. */
4060 /* Recover by calling this a parameter pack. */
4062 }
4063 }
4065 /* A template parameter is not modifiable. */
4074 processing_template_decl,
4079 }
4080 else
4081 {
4082 tree t;
4086 {
4088 /* This is for distinguishing between real templates and template
4089 template parameters */
4093 }
4094 else
4095 {
4097 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4100 }
4107 processing_template_decl,
4111 }
4115 /* Build requirements for the type/template parameter.
4116 This must be done after SET_DECL_TEMPLATE_PARM_P or
4117 process_template_parm could fail. */
4122 /* Build the parameter node linking the parameter declaration,
4123 its default argument (if any), and its constraints (if any). */
4128 }
4130 /* The end of a template parameter list has been reached. Process the
4131 tree list into a parameter vector, converting each parameter into a more
4132 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4133 as PARM_DECLs. */
4135 tree
4137 {
4142 /* Pop the dummy parameter level and add the real one. */
4145 current_template_parms
4150 {
4154 }
4159 }
4161 // Explicitly indicate the end of the template parameter list. We assume
4162 // that the current template parameters have been constructed and/or
4163 // managed explicitly, as when creating new template template parameters
4164 // from a shorthand constraint.
4165 void
4167 {
4169 }
4171 /* end_template_decl is called after a template declaration is seen. */
4173 void
4175 {
4181 /* This matches the pushlevel in begin_template_parm_list. */
4186 }
4188 /* Takes a TREE_LIST representing a template parameter and convert it
4189 into an argument suitable to be passed to the type substitution
4190 functions. Note that If the TREE_LIST contains an error_mark
4191 node, the returned argument is error_mark_node. */
4193 tree
4195 {
4208 {
4212 {
4213 /* Turn this argument into a TYPE_ARGUMENT_PACK
4214 with a single element, which expands T. */
4223 }
4224 }
4225 else
4226 {
4230 {
4231 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4232 with a single element, which expands T. */
4244 }
4245 else
4247 }
4249 }
4251 /* Given a set of template parameters, return them as a set of template
4252 arguments. The template parameters are represented as a TREE_VEC, in
4253 the form documented in cp-tree.h for template arguments. */
4255 static tree
4257 {
4258 tree header;
4263 /* If there is only one level of template parameters, we do not
4264 create a TREE_VEC of TREE_VECs. Instead, we return a single
4265 TREE_VEC containing the arguments. */
4270 {
4283 else
4285 }
4288 }
4290 /* Within the declaration of a template, return the currently active
4291 template parameters as an argument TREE_VEC. */
4293 static tree
4295 {
4297 }
4299 /* Update the declared TYPE by doing any lookups which were thought to be
4300 dependent, but are not now that we know the SCOPE of the declarator. */
4302 tree
4304 {
4315 /* Don't bother building up the args in this case. */
4317 {
4318 /* tsubst in the args corresponding to the template parameters,
4319 including auto if present. Most things will be unchanged, but
4320 make_typename_type and tsubst_qualified_id will resolve
4321 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4324 tree pushed;
4326 {
4330 }
4335 }
4341 {
4344 else
4346 }
4348 }
4350 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4351 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4352 the new template is a member template. */
4354 tree
4356 {
4364 }
4366 struct template_parm_data
4367 {
4368 /* The level of the template parameters we are currently
4369 processing. */
4372 /* The index of the specialization argument we are currently
4373 processing. */
4376 /* An array whose size is the number of template parameters. The
4377 elements are nonzero if the parameter has been used in any one
4378 of the arguments processed so far. */
4381 /* An array whose size is the number of template arguments. The
4382 elements are nonzero if the argument makes use of template
4383 parameters of this level. */
4385 };
4387 /* Subroutine of push_template_decl used to see if each template
4388 parameter in a partial specialization is used in the explicit
4389 argument list. If T is of the LEVEL given in DATA (which is
4390 treated as a template_parm_data*), then DATA->PARMS is marked
4391 appropriately. */
4393 static int
4395 {
4403 {
4406 }
4408 /* Return zero so that for_each_template_parm will continue the
4409 traversal of the tree; we want to mark *every* template parm. */
4411 }
4413 /* Process the partial specialization DECL. */
4415 static tree
4417 {
4424 tree inner_parms;
4425 tree inst;
4435 /* A concept cannot be specialized. */
4437 {
4440 }
4445 /* We check that each of the template parameters given in the
4446 partial specialization is used in the argument list to the
4447 specialization. For example:
4449 template <class T> struct S;
4450 template <class T> struct S<T*>;
4452 The second declaration is OK because `T*' uses the template
4453 parameter T, whereas
4455 template <class T> struct S<int>;
4457 is no good. Even trickier is:
4459 template <class T>
4460 struct S1
4461 {
4462 template <class U>
4463 struct S2;
4464 template <class U>
4465 struct S2<T>;
4466 };
4468 The S2<T> declaration is actually invalid; it is a
4469 full-specialization. Of course,
4471 template <class U>
4472 struct S2<T (*)(U)>;
4474 or some such would have been OK. */
4482 {
4487 NULL,
4489 }
4492 {
4493 /* One of the template parms was not used in a deduced context in the
4494 specialization. */
4496 {
4500 }
4504 }
4509 /* [temp.class.spec]
4511 The argument list of the specialization shall not be identical to
4512 the implicit argument list of the primary template. */
4513 tree main_args
4516 && (!flag_concepts
4519 {
4523 else
4527 }
4529 /* A partial specialization that replaces multiple parameters of the
4530 primary template with a pack expansion is less specialized for those
4531 parameters. */
4533 {
4535 "primary template because it replaces multiple parameters "
4539 }
4541 /* [temp.class.spec]
4543 A partially specialized non-type argument expression shall not
4544 involve template parameters of the partial specialization except
4545 when the argument expression is a simple identifier.
4547 The type of a template parameter corresponding to a specialized
4548 non-type argument shall not be dependent on a parameter of the
4549 specialization.
4551 Also, we verify that pack expansions only occur at the
4552 end of the argument list. */
4556 {
4563 {
4564 /* Extract the arguments from the argument pack. We'll be
4565 iterating over these in the following loop. */
4568 }
4571 {
4573 /* Get the Jth argument in the parameter pack. */
4577 {
4578 /* Pack expansions must come at the end of the
4579 argument list. */
4582 {
4586 else
4589 }
4590 }
4593 /* We only care about the pattern. */
4599 /* This next two lines are the `argument expression is not just a
4600 simple identifier' condition and also the `specialized
4601 non-type argument' bit. */
4605 {
4609 arg);
4610 else
4611 {
4612 /* Look at the corresponding template parameter,
4613 marking which template parameters its type depends
4614 upon. */
4618 {
4619 /* We haven't yet initialized TPD2. Do so now. */
4621 /* The number of parameters here is the number in the
4622 main template, which, as checked in the assertion
4623 above, is NARGS. */
4627 }
4629 /* Mark the template parameters. But this time, we're
4630 looking for the template parameters of the main
4631 template, not in the specialization. */
4638 NULL,
4642 {
4643 /* The type depended on some template parameters.
4644 If they are fully specialized in the
4645 specialization, that's OK. */
4654 "type %qT of template argument %qE depends "
4656 "type %qT of template argument %qE depends "
4658 type,
4659 arg);
4660 }
4661 }
4662 }
4663 }
4664 }
4666 /* We should only get here once. */
4670 // Build the template decl.
4680 /* We didn't register this in check_explicit_specialization so we could
4681 wait until the constraints were set. */
4683 else
4693 {
4699 {
4707 "declaration of %qD ambiguates earlier template "
4711 "partial specialization of %qD after instantiation "
4713 }
4714 }
4717 }
4719 /* PARM is a template parameter of some form; return the corresponding
4720 TEMPLATE_PARM_INDEX. */
4722 static tree
4724 {
4737 }
4739 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4740 parameter packs used by the template parameter PARM. */
4742 static void
4744 {
4745 /* A type parm can't refer to another parm. */
4749 {
4753 }
4760 }
4762 /* PARM is a template parameter pack. Return any parameter packs used in
4763 its type or the type of any of its template parameters. If there are
4764 any such packs, it will be instantiated into a fixed template parameter
4765 list by partial instantiation rather than be fully deduced. */
4767 tree
4769 {
4770 /* This can only be true in a member template. */
4773 /* This can only be true for a parameter pack. */
4776 /* A type parm can't refer to another parm. */
4790 }
4792 /* Check that a template declaration's use of default arguments and
4793 parameter packs is not invalid. Here, PARMS are the template
4794 parameters. IS_PRIMARY is true if DECL is the thing declared by
4795 a primary template. IS_PARTIAL is true if DECL is a partial
4796 specialization.
4798 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4799 declaration (but not a definition); 1 indicates a declaration, 2
4800 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4801 emitted for extraneous default arguments.
4803 Returns TRUE if there were no errors found, FALSE otherwise. */
4805 bool
4808 {
4811 tree parm_level;
4814 /* [temp.param]
4816 A default template-argument shall not be specified in a
4817 function template declaration or a function template definition, nor
4818 in the template-parameter-list of the definition of a member of a
4819 class template. */
4823 /* You can't have a function template declaration in a local
4824 scope, nor you can you define a member of a class template in a
4825 local scope. */
4833 /* A lambda doesn't have an explicit declaration; don't complain
4834 about the parms of the enclosing class. */
4841 /* If this is either a friend defined in the scope of the class
4842 or a member function. */
4848 /* And, if it was a member function, it really was defined in
4849 the scope of the class. */
4852 /* We already checked these parameters when the template was
4853 declared, so there's no need to do it again now. This function
4854 was defined in class scope, but we're processing its body now
4855 that the class is complete. */
4858 /* Core issue 226 (C++0x only): the following only applies to class
4859 templates. */
4862 {
4863 /* [temp.param]
4865 If a template-parameter has a default template-argument, all
4866 subsequent template-parameters shall have a default
4867 template-argument supplied. */
4869 {
4876 {
4886 {
4888 /* For better subsequent error-recovery, we indicate that
4889 there should have been a default argument. */
4892 }
4894 && !is_friend_decl
4895 /* Don't complain about an enclosing partial
4896 specialization. */
4901 /* A fixed parameter pack will be partially
4902 instantiated into a fixed length list. */
4904 {
4905 /* A primary class template can only have one
4906 parameter pack, at the end of the template
4907 parameter list. */
4915 }
4916 }
4917 }
4918 }
4921 || is_partial
4922 || !is_primary
4924 /* For an ordinary class template, default template arguments are
4925 allowed at the innermost level, e.g.:
4926 template <class T = int>
4927 struct S {};
4928 but, in a partial specialization, they're not allowed even
4929 there, as we have in [temp.class.spec]:
4931 The template parameter list of a specialization shall not
4932 contain default template argument values.
4934 So, for a partial specialization, or for a function template
4935 (in C++98/C++03), we look at all of them. */
4936 ;
4937 else
4938 /* But, for a primary class template that is not a partial
4939 specialization we look at all template parameters except the
4940 innermost ones. */
4943 /* Figure out what error message to issue. */
4958 else
4959 /* Per [temp.param]/9, "A default template-argument shall not be
4960 specified in the template-parameter-lists of the definition of
4961 a member of a class template that appears outside of the member's
4962 class.", thus if we aren't handling a member of a class template
4963 there is no need to examine the parameters. */
4967 /* If we're inside a class definition, there's no need to
4968 examine the parameters to the class itself. On the one
4969 hand, they will be checked when the class is defined, and,
4970 on the other, default arguments are valid in things like:
4971 template <class T = double>
4972 struct S { template <class U> void f(U); };
4973 Here the default argument for `S' has no bearing on the
4974 declaration of `f'. */
4976 else
4977 /* Check everything. */
4983 {
4990 {
4995 {
4997 {
5004 }
5006 /* Clear out the default argument so that we are not
5007 confused later. */
5009 }
5010 }
5012 /* At this point, if we're still interested in issuing messages,
5013 they must apply to classes surrounding the object declared. */
5017 }
5020 }
5022 /* Worker for push_template_decl_real, called via
5023 for_each_template_parm. DATA is really an int, indicating the
5024 level of the parameters we are interested in. If T is a template
5025 parameter of that level, return nonzero. */
5027 static int
5029 {
5035 else
5038 }
5040 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5041 parameters given by current_template_args, or reuses a
5042 previously existing one, if appropriate. Returns the DECL, or an
5043 equivalent one, if it is replaced via a call to duplicate_decls.
5045 If IS_FRIEND is true, DECL is a friend declaration. */
5047 tree
5049 {
5050 tree tmpl;
5051 tree args;
5052 tree info;
5053 tree ctx;
5057 /* True if the template is a member template, in the sense of
5058 [temp.mem]. */
5064 /* See if this is a partial specialization. */
5077 /* For a friend, we want the context of the friend function, not
5078 the type of which it is a friend. */
5082 /* In the case of a virtual function, we want the class in which
5083 it is defined. */
5085 else
5086 /* Otherwise, if we're currently defining some class, the DECL
5087 is assumed to be a member of the class. */
5096 /* See if this is a primary template. */
5099 /* A friend template that specifies a class context, i.e.
5100 template <typename T> friend void A<T>::f();
5101 is not primary. */
5106 else
5110 {
5117 {
5120 }
5122 {
5124 {
5127 }
5129 {
5130 /* [temp.mem]
5132 A destructor shall not be a member template. */
5135 }
5142 {
5143 /* [basic.stc.dynamic.allocation]
5145 An allocation function can be a function
5146 template. ... Template allocation functions shall
5147 have two or more parameters. */
5150 }
5151 }
5157 /* alias-declaration */
5161 else
5162 {
5165 }
5166 }
5168 /* Check to see that the rules regarding the use of default
5169 arguments are not being violated. */
5173 /* Ensure that there are no parameter packs in the type of this
5174 declaration that have not been expanded. */
5176 {
5177 /* Check each of the arguments individually to see if there are
5178 any bare parameter packs. */
5184 {
5187 {
5188 /* This is a PARM_DECL that contains unexpanded parameter
5189 packs. We have already complained about this in the
5190 check_for_bare_parameter_packs call, so just replace
5191 these types with ERROR_MARK_NODE. */
5194 }
5198 }
5200 /* Check for bare parameter packs in the return type and the
5201 exception specifiers. */
5203 /* Errors were already issued, set return type to int
5204 as the frontend doesn't expect error_mark_node as
5205 the return type. */
5209 }
5214 {
5217 }
5230 {
5235 /* If DECL is a TYPE_DECL for a class-template, then there won't
5236 be DECL_LANG_SPECIFIC. The information equivalent to
5237 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5241 {
5242 /* Since a template declaration already existed for this
5243 class-type, we must be redeclaring it here. Make sure
5244 that the redeclaration is valid. */
5246 current_template_parms,
5248 /* We don't need to create a new TEMPLATE_DECL; just use the
5249 one we already had. */
5251 }
5252 else
5253 {
5255 member_template_p);
5260 {
5261 /* A specialization of a member template of a template
5262 class. */
5266 }
5267 }
5268 }
5269 else
5270 {
5276 {
5279 }
5287 {
5288 tree new_tmpl;
5290 /* The declaration is a specialization of a member
5291 template, declared outside the class. Therefore, the
5292 innermost template arguments will be NULL, so we
5293 replace them with the arguments determined by the
5294 earlier call to check_explicit_specialization. */
5297 new_tmpl
5299 member_template_p);
5309 args,
5312 }
5314 /* Make sure the template headers we got make sense. */
5319 {
5324 }
5325 else
5327 {
5332 {
5336 else
5340 /* Avoid crash in import_export_decl. */
5343 }
5348 /* Can happen in erroneous input. */
5350 else
5352 }
5354 /* Check that the parms are used in the appropriate qualifying scopes
5355 in the declarator. */
5359 {
5365 /* Avoid crash in import_export_decl. */
5368 }
5369 }
5374 /* Push template declarations for global functions and types. Note
5375 that we do not try to push a global template friend declared in a
5376 template class; such a thing may well depend on the template
5377 parameters of the class. */
5380 {
5385 /* Hide template friend classes that haven't been declared yet. */
5387 {
5390 }
5391 }
5394 {
5400 {
5403 /* It is a conversion operator. See if the type converted to
5404 depends on innermost template operands. */
5407 depth))
5409 }
5411 /* Give template template parms a DECL_CONTEXT of the template
5412 for which they are a parameter. */
5415 {
5419 }
5425 }
5427 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5428 back to its most general template. If TMPL is a specialization,
5429 ARGS may only have the innermost set of arguments. Add the missing
5430 argument levels if necessary. */
5438 else
5439 {
5444 }
5447 && !is_friend
5450 /* Set DECL_COMDAT on template instantiations; if we force
5451 them to be emitted by explicit instantiation or -frepo,
5452 mark_needed will tell cgraph to do the right thing. */
5456 }
5458 tree
5460 {
5462 }
5464 /* FN is an inheriting constructor that inherits from the constructor
5465 template INHERITED; turn FN into a constructor template with a matching
5466 template header. */
5468 tree
5470 {
5471 tree inner_parms
5474 tree parms
5485 }
5487 /* Called when a class template TYPE is redeclared with the indicated
5488 template PARMS, e.g.:
5490 template <class T> struct S;
5491 template <class T> struct S {}; */
5493 bool
5495 {
5496 tree tmpl;
5497 tree tmpl_parms;
5501 {
5504 }
5508 /* The type is nested in some template class. Nothing to worry
5509 about here; there are no new template parameters for the nested
5510 type. */
5514 {
5516 tmpl);
5518 }
5524 {
5534 }
5537 {
5538 tree tmpl_parm;
5539 tree parm;
5540 tree tmpl_default;
5541 tree parm_default;
5555 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5556 TEMPLATE_DECL. */
5566 {
5570 }
5573 {
5574 /* We have in [temp.param]:
5576 A template-parameter may not be given default arguments
5577 by two different declarations in the same scope. */
5582 }
5585 /* Update the previous template parameters (which are the ones
5586 that will really count) with the new default value. */
5589 /* Update the new parameters, too; they'll be used as the
5590 parameters for any members. */
5593 /* Give each template template parm in this redeclaration a
5594 DECL_CONTEXT of the template for which they are a parameter. */
5596 {
5599 }
5600 }
5602 // Cannot redeclare a class template with a different set of constraints.
5604 {
5609 }
5612 }
5614 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5615 to be used when the caller has already checked
5616 (processing_template_decl
5617 && !instantiation_dependent_expression_p (expr)
5618 && potential_constant_expression (expr))
5619 and cleared processing_template_decl. */
5621 tree
5623 {
5626 complain,
5630 }
5632 /* Simplify EXPR if it is a non-dependent expression. Returns the
5633 (possibly simplified) expression. */
5635 tree
5637 {
5641 /* If we're in a template, but EXPR isn't value dependent, simplify
5642 it. We're supposed to treat:
5644 template <typename T> void f(T[1 + 1]);
5645 template <typename T> void f(T[2]);
5647 as two declarations of the same function, for example. */
5651 {
5652 processing_template_decl_sentinel s;
5654 }
5656 }
5658 tree
5660 {
5662 }
5664 /* True iff T is a specialization of a variable template. */
5666 bool
5668 {
5673 }
5675 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5676 template declaration, or a TYPE_DECL for an alias declaration. */
5678 bool
5680 {
5688 }
5690 /* Return TRUE iff T is a specialization of an alias template. */
5692 bool
5694 {
5695 /* It's an alias template specialization if it's an alias and its
5696 TYPE_NAME is a specialization of a primary template. */
5698 {
5702 {
5705 }
5706 }
5708 }
5710 /* An alias template is complex from a SFINAE perspective if a template-id
5711 using that alias can be ill-formed when the expansion is not, as with
5712 the void_t template. We determine this by checking whether the
5713 expansion for the alias template uses all its template parameters. */
5715 struct uses_all_template_parms_data
5716 {
5719 };
5721 static int
5723 {
5731 }
5733 static bool
5735 {
5750 }
5752 /* Return TRUE iff T is a specialization of a complex alias template with
5753 dependent template-arguments. */
5755 bool
5757 {
5760 && (any_dependent_template_arguments_p
5762 }
5764 /* Return the number of innermost template parameters in TMPL. */
5766 static int
5768 {
5771 }
5773 /* Return either TMPL or another template that it is equivalent to under DR
5774 1286: An alias that just changes the name of a template is equivalent to
5775 the other template. */
5777 static tree
5779 {
5782 {
5785 {
5790 {
5791 tree alias_args = INNERMOST_TEMPLATE_ARGS
5795 /* The alias type is equivalent to the pattern of the
5796 underlying template, so strip the alias. */
5799 }
5800 }
5802 }
5804 }
5806 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5807 must be a function or a pointer-to-function type, as specified
5808 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5809 and check that the resulting function has external linkage. */
5811 static tree
5813 tsubst_flags_t complain)
5814 {
5817 linkage_kind linkage;
5829 /* [temp.arg.nontype]/1
5831 A template-argument for a non-type, non-template template-parameter
5832 shall be one of:
5833 [...]
5834 -- the address of an object or function with external [C++11: or
5835 internal] linkage. */
5838 {
5840 {
5846 else
5849 }
5851 }
5855 {
5857 {
5862 else
5866 }
5868 }
5871 }
5873 /* Subroutine of convert_nontype_argument.
5874 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5875 Emit an error otherwise. */
5877 static bool
5879 tsubst_flags_t complain)
5880 {
5891 {
5895 }
5897 }
5899 /* Returns TRUE iff the address of OP is value-dependent.
5901 14.6.2.4 [temp.dep.temp]:
5902 A non-integral non-type template-argument is dependent if its type is
5903 dependent or it has either of the following forms
5904 qualified-id
5905 & qualified-id
5906 and contains a nested-name-specifier which specifies a class-name that
5907 names a dependent type.
5909 We generalize this to just say that the address of a member of a
5910 dependent class is value-dependent; the above doesn't cover the
5911 address of a static data member named with an unqualified-id. */
5913 static bool
5915 {
5916 /* We could use get_inner_reference here, but there's no need;
5917 this is only relevant for template non-type arguments, which
5918 can only be expressed as &id-expression. */
5920 {
5924 }
5927 }
5929 /* The next set of functions are used for providing helpful explanatory
5930 diagnostics for failed overload resolution. Their messages should be
5931 indented by two spaces for consistency with the messages in
5932 call.c */
5934 static int
5936 {
5938 }
5940 static int
5942 {
5947 }
5949 static int
5951 {
5953 }
5955 static int
5957 {
5963 }
5965 static int
5967 {
5971 }
5973 static int
5975 {
5978 " template parameter %qD is not a parameter pack, but "
5982 }
5984 static int
5986 {
5989 " template argument %qE does not match "
5993 }
5995 static int
5997 {
6001 }
6003 static int
6005 {
6011 }
6013 static int
6015 {
6017 {
6022 else
6024 " deduced conflicting values for non-type parameter "
6026 }
6028 }
6030 static int
6032 {
6035 " variable-sized array type %qT is not "
6037 arg);
6039 }
6041 static int
6043 {
6047 arg);
6049 }
6051 static int
6053 {
6055 {
6061 else
6066 }
6068 }
6070 static int
6072 {
6074 }
6076 static int
6079 {
6081 }
6083 static int
6086 {
6092 }
6094 static int
6097 {
6100 {
6108 }
6110 }
6112 static int
6114 {
6117 " template parameters of a template template argument are "
6120 }
6122 static int
6124 {
6130 }
6132 static int
6134 {
6139 }
6141 static int
6143 {
6147 arg);
6149 }
6151 /* Attempt to convert the non-type template parameter EXPR to the
6152 indicated TYPE. If the conversion is successful, return the
6153 converted value. If the conversion is unsuccessful, return
6154 NULL_TREE if we issued an error message, or error_mark_node if we
6155 did not. We issue error messages for out-and-out bad template
6156 parameters, but not simply because the conversion failed, since we
6157 might be just trying to do argument deduction. Both TYPE and EXPR
6158 must be non-dependent.
6160 The conversion follows the special rules described in
6161 [temp.arg.nontype], and it is much more strict than an implicit
6162 conversion.
6164 This function is called twice for each template argument (see
6165 lookup_template_class for a more accurate description of this
6166 problem). This means that we need to handle expressions which
6167 are not valid in a C++ source, but can be created from the
6168 first call (for instance, casts to perform conversions). These
6169 hacks can go away after we fix the double coercion problem. */
6171 static tree
6173 {
6174 tree expr_type;
6176 /* Detect immediately string literals as invalid non-type argument.
6177 This special-case is not needed for correctness (we would easily
6178 catch this later), but only to provide better diagnostic for this
6179 common user mistake. As suggested by DR 100, we do not mention
6180 linkage issues in the diagnostic as this is not the point. */
6181 /* FIXME we're making this OK. */
6183 {
6189 }
6191 /* Add the ADDR_EXPR now for the benefit of
6192 value_dependent_expression_p. */
6195 {
6199 }
6201 /* If we are in a template, EXPR may be non-dependent, but still
6202 have a syntactic, rather than semantic, form. For example, EXPR
6203 might be a SCOPE_REF, rather than the VAR_DECL to which the
6204 SCOPE_REF refers. Preserving the qualifying scope is necessary
6205 so that access checking can be performed when the template is
6206 instantiated -- but here we need the resolved form so that we can
6207 convert the argument. */
6213 && processing_template_decl
6222 else
6225 /* If the argument is non-dependent, perform any conversions in
6226 non-dependent context as well. */
6231 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6232 to a non-type argument of "nullptr". */
6236 /* In C++11, integral or enumeration non-type template arguments can be
6237 arbitrary constant expressions. Pointer and pointer to
6238 member arguments can be general constant expressions that evaluate
6239 to a null value, but otherwise still need to be of a specific form. */
6241 {
6243 /* A PTRMEM_CST is already constant, and a valid template
6244 argument for a parameter of pointer to member type, we just want
6245 to leave it in that form rather than lower it to a
6250 {
6254 {
6258 }
6259 }
6261 {
6266 }
6267 }
6269 /* HACK: Due to double coercion, we can get a
6270 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6271 which is the tree that we built on the first call (see
6272 below when coercing to reference to object or to reference to
6273 function). We just strip everything and get to the arg.
6274 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6275 for examples. */
6277 {
6283 {
6284 /* ??? Maybe we could use convert_from_reference here, but we
6285 would need to relax its constraints because the NOP_EXPR
6286 could actually change the type to something more cv-qualified,
6287 and this is not folded by convert_from_reference. */
6292 && (same_type_ignoring_top_level_qualifiers_p
6295 {
6298 }
6299 }
6300 }
6302 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6303 parameter is a pointer to object, through decay and
6304 qualification conversion. Let's strip everything. */
6306 {
6311 {
6312 /* Skip the ADDR_EXPR only if it is part of the decay for
6313 an array. Otherwise, it is part of the original argument
6314 in the source code. */
6319 }
6320 }
6322 /* [temp.arg.nontype]/5, bullet 1
6324 For a non-type template-parameter of integral or enumeration type,
6325 integral promotions (_conv.prom_) and integral conversions
6326 (_conv.integral_) are applied. */
6328 {
6337 /* Notice that there are constant expressions like '4 % 0' which
6338 do not fold into integer constants. */
6340 {
6342 {
6353 /* else cxx_constant_value complained but gave us
6354 a real constant, so go ahead. */
6356 }
6357 else
6359 }
6361 /* Avoid typedef problems. */
6364 }
6365 /* [temp.arg.nontype]/5, bullet 2
6367 For a non-type template-parameter of type pointer to object,
6368 qualification conversions (_conv.qual_) and the array-to-pointer
6369 conversion (_conv.array_) are applied. */
6371 {
6372 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6374 A template-argument for a non-type, non-template template-parameter
6375 shall be one of: [...]
6377 -- the name of a non-type template-parameter;
6378 -- the address of an object or function with external linkage, [...]
6379 expressed as "& id-expression" where the & is optional if the name
6380 refers to a function or array, or if the corresponding
6381 template-parameter is a reference.
6383 Here, we do not care about functions, as they are invalid anyway
6384 for a parameter of type pointer-to-object. */
6387 /* Non-type template parameters are OK. */
6388 ;
6393 {
6395 {
6398 "because %qD is a variable, not the address of "
6401 }
6403 {
6409 }
6410 /* Other values, like integer constants, might be valid
6411 non-type arguments of some other type. */
6413 }
6414 else
6415 {
6416 tree decl;
6421 {
6426 }
6428 {
6434 }
6436 {
6441 }
6442 }
6451 }
6452 /* [temp.arg.nontype]/5, bullet 3
6454 For a non-type template-parameter of type reference to object, no
6455 conversions apply. The type referred to by the reference may be more
6456 cv-qualified than the (otherwise identical) type of the
6457 template-argument. The template-parameter is bound directly to the
6458 template-argument, which must be an lvalue. */
6460 {
6462 expr_type))
6466 {
6471 }
6474 {
6479 }
6481 /* [temp.arg.nontype]/1
6483 A template-argument for a non-type, non-template template-parameter
6484 shall be one of: [...]
6486 -- the address of an object or function with external linkage. */
6489 {
6492 {
6495 "because a reference variable does not have a constant "
6498 }
6499 }
6502 {
6508 }
6510 /* DR 1155 allows internal linkage in C++11 and up. */
6513 {
6519 }
6522 }
6523 /* [temp.arg.nontype]/5, bullet 4
6525 For a non-type template-parameter of type pointer to function, only
6526 the function-to-pointer conversion (_conv.func_) is applied. If the
6527 template-argument represents a set of overloaded functions (or a
6528 pointer to such), the matching function is selected from the set
6529 (_over.over_). */
6531 {
6532 /* If the argument is a template-id, we might not have enough
6533 context information to decay the pointer. */
6535 {
6539 }
6542 /* Null pointer values are OK in C++11. */
6548 }
6549 /* [temp.arg.nontype]/5, bullet 5
6551 For a non-type template-parameter of type reference to function, no
6552 conversions apply. If the template-argument represents a set of
6553 overloaded functions, the matching function is selected from the set
6554 (_over.over_). */
6556 {
6558 {
6560 {
6565 }
6567 }
6574 }
6575 /* [temp.arg.nontype]/5, bullet 6
6577 For a non-type template-parameter of type pointer to member function,
6578 no conversions apply. If the template-argument represents a set of
6579 overloaded member functions, the matching member function is selected
6580 from the set (_over.over_). */
6582 {
6587 /* [temp.arg.nontype] bullet 1 says the pointer to member
6588 expression must be a pointer-to-member constant. */
6592 /* There is no way to disable standard conversions in
6593 resolve_address_of_overloaded_function (called by
6594 instantiate_type). It is possible that the call succeeded by
6595 converting &B::I to &D::I (where B is a base of D), so we need
6596 to reject this conversion here.
6598 Actually, even if there was a way to disable standard conversions,
6599 it would still be better to reject them here so that we can
6600 provide a superior diagnostic. */
6602 {
6604 {
6608 /* If we are just one standard conversion off, explain. */
6612 }
6614 }
6615 }
6616 /* [temp.arg.nontype]/5, bullet 7
6618 For a non-type template-parameter of type pointer to data member,
6619 qualification conversions (_conv.qual_) are applied. */
6621 {
6622 /* [temp.arg.nontype] bullet 1 says the pointer to member
6623 expression must be a pointer-to-member constant. */
6630 }
6632 {
6634 {
6639 }
6641 }
6642 /* A template non-type parameter must be one of the above. */
6643 else
6646 /* Sanity check: did we actually convert the argument to the
6647 right type? */
6651 }
6653 /* Subroutine of coerce_template_template_parms, which returns 1 if
6654 PARM_PARM and ARG_PARM match using the rule for the template
6655 parameters of template template parameters. Both PARM and ARG are
6656 template parameters; the rest of the arguments are the same as for
6657 coerce_template_template_parms.
6658 */
6659 static int
6661 tree arg,
6662 tsubst_flags_t complain,
6663 tree in_decl,
6664 tree outer_args)
6665 {
6674 {
6676 /* We encounter instantiations of templates like
6677 template <template <template <class> class> class TT>
6678 class C; */
6679 {
6686 }
6687 /* Fall through. */
6692 /* Argument is a parameter pack but parameter is not. */
6697 /* The tsubst call is used to handle cases such as
6699 template <int> class C {};
6700 template <class T, template <T> class TT> class D {};
6701 D<int, C> d;
6703 i.e. the parameter list of TT depends on earlier parameters. */
6705 {
6710 }
6714 /* Argument is a parameter pack but parameter is not. */
6721 }
6724 }
6727 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6728 template template parameters. Both PARM_PARMS and ARG_PARMS are
6729 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6730 or PARM_DECL.
6732 Consider the example:
6733 template <class T> class A;
6734 template<template <class U> class TT> class B;
6736 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6737 the parameters to A, and OUTER_ARGS contains A. */
6739 static int
6741 tree arg_parms,
6742 tsubst_flags_t complain,
6743 tree in_decl,
6744 tree outer_args)
6745 {
6756 /* Determine whether we have a parameter pack at the end of the
6757 template template parameter's template parameter list. */
6759 {
6766 {
6780 }
6781 }
6787 /* Check all of the template parameters except the parameter pack at
6788 the end (if any). */
6790 {
6799 outer_args))
6802 }
6805 {
6806 /* Check each of the template parameters in the template
6807 argument against the template parameter pack at the end of
6808 the template template parameter. */
6815 {
6822 outer_args))
6824 }
6825 }
6828 }
6830 /* Verifies that the deduced template arguments (in TARGS) for the
6831 template template parameters (in TPARMS) represent valid bindings,
6832 by comparing the template parameter list of each template argument
6833 to the template parameter list of its corresponding template
6834 template parameter, in accordance with DR150. This
6835 routine can only be called after all template arguments have been
6836 deduced. It will return TRUE if all of the template template
6837 parameter bindings are okay, FALSE otherwise. */
6838 bool
6840 {
6844 /* We're dealing with template parms in this process. */
6850 {
6855 {
6860 {
6861 /* Look inside the argument pack. */
6864 }
6867 {
6871 /* Extract the next argument from the argument
6872 pack. */
6876 /* Look at the pattern of the pack expansion. */
6879 /* Extract the template parameters from the template
6880 argument. */
6886 /* Verify that we can coerce the template template
6887 parameters from the template argument to the template
6888 parameter. This requires an exact match. */
6890 && !coerce_template_template_parms
6892 targ_parms,
6893 tf_none,
6894 tparm,
6895 targs))
6896 {
6899 }
6900 }
6901 }
6902 }
6904 out:
6908 }
6910 /* Since type attributes aren't mangled, we need to strip them from
6911 template type arguments. */
6913 static tree
6915 {
6924 }
6926 // A template declaration can be substituted for a constrained
6927 // template template parameter only when the argument is more
6928 // constrained than the parameter.
6929 static bool
6931 {
6934 /* For now, allow constrained template template arguments
6935 and unconstrained template template parameters. */
6941 // If the template parameter is constrained, we need to rewrite its
6942 // constraints in terms of the ARG's template parameters. This ensures
6943 // that all of the template parameter types will have the same depth.
6944 //
6945 // Note that this is only valid when coerce_template_template_parm is
6946 // true for the innermost template parameters of PARM and ARG. In other
6947 // words, because coercion is successful, this conversion will be valid.
6949 {
6956 }
6959 }
6961 // Convert a placeholder argument into a binding to the original
6962 // parameter. The original parameter is saved as the TREE_TYPE of
6963 // ARG.
6966 {
6969 }
6971 /* Convert the indicated template ARG as necessary to match the
6972 indicated template PARM. Returns the converted ARG, or
6973 error_mark_node if the conversion was unsuccessful. Error and
6974 warning messages are issued under control of COMPLAIN. This
6975 conversion is for the Ith parameter in the parameter list. ARGS is
6976 the full set of template arguments deduced so far. */
6978 static tree
6980 tree arg,
6981 tree args,
6982 tsubst_flags_t complain,
6984 tree in_decl)
6985 {
6986 tree orig_arg;
6987 tree val;
6993 /* Trivially convert placeholders. */
6999 {
7000 /* The template argument was the name of some
7001 member function. That's usually
7002 invalid, but static members are OK. In any
7003 case, grab the underlying fields/functions
7004 and issue an error later if required. */
7007 }
7015 /* When determining whether an argument pack expansion is a template,
7016 look at the pattern. */
7020 /* Deal with an injected-class-name used as a template template arg. */
7022 {
7025 {
7035 }
7036 }
7038 is_tmpl_type =
7054 {
7056 {
7060 }
7063 "to refer to a type member of a template parameter, "
7068 typename_type,
7069 complain);
7072 }
7074 {
7076 {
7078 {
7090 else
7093 }
7094 }
7096 }
7098 {
7100 {
7107 else
7110 }
7112 }
7115 {
7117 {
7121 /* The number of argument required is not known yet.
7122 Just accept it for now. */
7124 else
7125 {
7127 tree argparm;
7129 /* Strip alias templates that are equivalent to another
7130 template. */
7136 args))
7137 {
7140 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7141 TEMPLATE_DECL. */
7143 {
7148 }
7149 }
7150 else
7151 {
7153 {
7160 }
7163 }
7165 // Check that the constraints are compatible before allowing the
7166 // substitution.
7169 {
7171 {
7177 }
7179 }
7180 }
7181 }
7182 else
7184 /* We only form one instance of each template specialization.
7185 Therefore, if we use a non-canonical variant (i.e., a
7186 typedef), any future messages referring to the type will use
7187 the typedef, which is confusing if those future uses do not
7188 themselves also use the typedef. */
7191 }
7192 else
7193 {
7200 {
7203 else
7204 {
7205 /* Not sure if this is reachable, but it doesn't hurt
7206 to be robust. */
7209 }
7210 }
7213 /* We used to call digest_init here. However, digest_init
7214 will report errors, which we don't want when complain
7215 is zero. More importantly, digest_init will try too
7216 hard to convert things: for example, `0' should not be
7217 converted to pointer type at this point according to
7218 the standard. Accepting this is not merely an
7219 extension, since deciding whether or not these
7220 conversions can occur is part of determining which
7221 function template to call, or whether a given explicit
7222 argument specification is valid. */
7224 else
7225 {
7228 }
7236 {
7237 /* Reject template arguments that are references to built-in
7238 functions with no library fallbacks. */
7246 }
7249 {
7250 /* Strip typedefs from the SCOPE_REF. */
7253 complain);
7256 }
7257 }
7260 }
7262 /* Coerces the remaining template arguments in INNER_ARGS (from
7263 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7264 Returns the coerced argument pack. PARM_IDX is the position of this
7265 parameter in the template parameter list. ARGS is the original
7266 template argument list. */
7267 static tree
7270 tree args,
7271 tree inner_args,
7273 tree new_args,
7275 tree in_decl,
7276 tsubst_flags_t complain)
7277 {
7280 tree packed_args;
7281 tree argument_pack;
7288 {
7289 /* When the template parameter is a non-type template parameter pack
7290 or template template parameter pack whose type or template
7291 parameters use parameter packs, we know exactly how many arguments
7292 we are looking for. Build a vector of the instantiated decls for
7293 these template parameters in PACKED_PARMS. */
7294 /* We can't use make_pack_expansion here because it would interpret a
7295 _DECL as a use rather than a declaration. */
7309 /* If we're doing a partial instantiation of a member template,
7310 verify that all of the types used for the non-type
7311 template parameter pack are, in fact, valid for non-type
7312 template parameters. */
7315 {
7318 {
7322 }
7323 /* We don't know how many args we have yet, just
7324 use the unconverted ones for now. */
7326 }
7329 }
7330 /* Check if we have a placeholder pack, which indicates we're
7331 in the context of a introduction list. In that case we want
7332 to match this pack to the single placeholder. */
7336 {
7339 }
7340 else
7343 /* Convert the remaining arguments, which will be a part of the
7344 parameter pack "parm". */
7346 {
7352 {
7353 /* Once we've packed as many args as we have types, stop. */
7357 /* We don't know how many args we have yet, just
7358 use the unconverted ones for now. */
7360 else
7362 }
7365 {
7368 }
7369 else
7372 in_decl);
7376 }
7380 {
7385 }
7390 else
7391 {
7396 }
7403 }
7405 /* Returns the number of pack expansions in the template argument vector
7406 ARGS. */
7408 static int
7410 {
7415 {
7419 }
7421 }
7423 /* Convert all template arguments to their appropriate types, and
7424 return a vector containing the innermost resulting template
7425 arguments. If any error occurs, return error_mark_node. Error and
7426 warning messages are issued under control of COMPLAIN.
7428 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7429 for arguments not specified in ARGS. Otherwise, if
7430 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7431 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7432 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7433 ARGS. */
7435 static tree
7437 tree args,
7438 tree in_decl,
7439 tsubst_flags_t complain,
7442 {
7444 tree orig_inner_args;
7445 tree inner_args;
7446 tree new_args;
7447 tree new_inner_args;
7451 /* When used as a boolean value, indicates whether this is a
7452 variadic template parameter list. Since it's an int, we can also
7453 subtract it from nparms to get the number of non-variadic
7454 parameters. */
7459 /* Likewise for parameters with default arguments. */
7467 /* Determine if there are any parameter packs or default arguments. */
7469 {
7477 }
7480 /* If there are no parameters that follow a parameter pack, we need to
7481 expand any argument packs so that we can deduce a parameter pack from
7482 some non-packed args followed by an argument pack, as in variadic85.C.
7483 If there are such parameters, we need to leave argument packs intact
7484 so the arguments are assigned properly. This can happen when dealing
7485 with a nested class inside a partial specialization of a class
7486 template, as in variadic92.C, or when deducing a template parameter pack
7487 from a sub-declarator, as in variadic114.C. */
7491 /* Count any pack expansion args. */
7497 && require_all_args
7498 && !variadic_args_p
7499 && (!use_default_args
7502 {
7504 {
7506 {
7510 }
7511 else
7518 }
7521 }
7522 /* We can't pass a pack expansion to a non-pack parameter of an alias
7523 template (DR 1430). */
7527 && variadic_args_p
7529 {
7531 {
7533 {
7539 {
7542 "pack expansion argument for non-pack parameter "
7544 else
7546 "pack expansion argument for non-pack parameter "
7550 }
7551 }
7553 found:;
7554 }
7556 }
7558 /* We need to evaluate the template arguments, even though this
7559 template-id may be nested within a "sizeof". */
7568 {
7569 tree arg;
7570 tree parm;
7572 /* Get the Ith template parameter. */
7576 {
7579 }
7581 /* Calculate the next argument. */
7584 else
7589 {
7590 /* Some arguments will be placed in the
7591 template parameter pack PARM. */
7598 {
7599 /* We don't know how many args we have yet, just use the
7600 unconverted (and still packed) ones for now. */
7604 }
7608 /* Store this argument. */
7610 {
7611 lost++;
7612 /* We are done with all of the arguments. */
7614 }
7615 else
7616 {
7619 }
7622 }
7624 {
7626 {
7627 /* "If every valid specialization of a variadic template
7628 requires an empty template parameter pack, the template is
7629 ill-formed, no diagnostic required." So check that the
7630 pattern works with this parameter. */
7635 in_decl);
7637 {
7641 }
7643 /* Recover from missing typename. */
7647 /* We don't know how many args we have yet, just
7648 use the unconverted ones for now. */
7652 }
7653 }
7655 {
7656 /* There must be a default arg in this case. */
7659 /* The position of the first default template argument,
7660 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7661 Record that. */
7665 }
7666 else
7670 {
7673 }
7675 /* This only occurs if there was an error in the template
7676 parameter list itself (which we would already have
7677 reported) that we are trying to recover from, e.g., a class
7678 template with a parameter list such as
7679 template<typename..., typename>. */
7681 else
7687 lost++;
7689 }
7694 {
7696 {
7701 }
7703 }
7713 }
7715 /* Convert all template arguments to their appropriate types, and
7716 return a vector containing the innermost resulting template
7717 arguments. If any error occurs, return error_mark_node. Error and
7718 warning messages are not issued.
7720 Note that no function argument deduction is performed, and default
7721 arguments are used to fill in unspecified arguments. */
7722 tree
7724 {
7726 }
7728 /* Convert all template arguments to their appropriate type, and
7729 instantiate default arguments as needed. This returns a vector
7730 containing the innermost resulting template arguments, or
7731 error_mark_node if unsuccessful. */
7732 tree
7734 tsubst_flags_t complain)
7735 {
7737 }
7739 /* Like coerce_template_parms. If PARMS represents all template
7740 parameters levels, this function returns a vector of vectors
7741 representing all the resulting argument levels. Note that in this
7742 case, only the innermost arguments are coerced because the
7743 outermost ones are supposed to have been coerced already.
7745 Otherwise, if PARMS represents only (the innermost) vector of
7746 parameters, this function returns a vector containing just the
7747 innermost resulting arguments. */
7749 static tree
7751 tree args,
7752 tree in_decl,
7753 tsubst_flags_t complain,
7756 {
7759 tree coerced_args;
7762 {
7764 tree level;
7770 {
7771 tree l;
7775 require_all_args,
7776 use_default_args);
7777 else
7784 }
7785 }
7786 else
7789 require_all_args,
7790 use_default_args);
7792 }
7794 /* Returns 1 if template args OT and NT are equivalent. */
7796 static int
7798 {
7805 /* For member templates */
7814 {
7831 }
7833 {
7834 /* We get here probably because we are in the middle of substituting
7835 into the pattern of a pack expansion. In that case the
7836 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7837 interested in. So we want to use the initial pack argument for
7838 the comparison. */
7843 }
7845 {
7848 /* Don't treat an alias template specialization with dependent
7849 arguments as equivalent to its underlying type when used as a
7850 template argument; we need them to be distinct so that we
7851 substitute into the specialization arguments at instantiation
7852 time. And aliases can't be equivalent without being ==, so
7853 we don't need to look any deeper. */
7856 else
7858 }
7861 else
7862 {
7863 /* Try to treat a template non-type argument that has been converted
7864 to the parameter type as equivalent to one that hasn't yet. */
7877 }
7878 }
7880 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7881 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7882 NEWARG_PTR with the offending arguments if they are non-NULL. */
7884 static int
7887 {
7900 {
7905 {
7911 }
7912 }
7914 }
7916 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7917 of template arguments. Returns 0 otherwise. */
7919 int
7921 {
7923 }
7925 static void
7927 {
7937 /* We are called both from instantiate_decl, where we've already had a
7938 tinst_level pushed, and instantiate_template, where we haven't.
7939 Compensate. */
7950 else
7959 }
7962 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7963 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7964 documentation for TEMPLATE_ID_EXPR. */
7966 tree
7968 {
7969 tree type;
7977 {
7980 }
7983 {
7985 unknown_type_node,
7987 arglist);
7989 }
7996 }
7998 /* Within the scope of a template class S<T>, the name S gets bound
7999 (in build_self_reference) to a TYPE_DECL for the class, not a
8000 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8001 or one of its enclosing classes, and that type is a template,
8002 return the associated TEMPLATE_DECL. Otherwise, the original
8003 DECL is returned.
8005 Also handle the case when DECL is a TREE_LIST of ambiguous
8006 injected-class-names from different bases. */
8008 tree
8010 {
8014 /* DR 176: A lookup that finds an injected-class-name (10.2
8015 [class.member.lookup]) can result in an ambiguity in certain cases
8016 (for example, if it is found in more than one base class). If all of
8017 the injected-class-names that are found refer to specializations of
8018 the same class template, and if the name is followed by a
8019 template-argument-list, the reference refers to the class template
8020 itself and not a specialization thereof, and is not ambiguous. */
8022 {
8025 {
8031 }
8034 else
8036 }
8042 }
8044 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8045 parameters, find the desired type.
8047 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8049 IN_DECL, if non-NULL, is the template declaration we are trying to
8050 instantiate.
8052 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8053 the class we are looking up.
8055 Issue error and warning messages under control of COMPLAIN.
8057 If the template class is really a local class in a template
8058 function, then the FUNCTION_CONTEXT is the function in which it is
8059 being instantiated.
8061 ??? Note that this function is currently called *twice* for each
8062 template-id: the first time from the parser, while creating the
8063 incomplete type (finish_template_type), and the second type during the
8064 real instantiation (instantiate_template_class). This is surely something
8065 that we want to avoid. It also causes some problems with argument
8066 coercion (see convert_nontype_argument for more information on this). */
8068 static tree
8071 {
8073 tree t;
8076 spec_entry elt;
8077 hashval_t hash;
8080 {
8084 else
8085 {
8092 }
8095 }
8097 {
8100 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8101 an implicit typename for the second A. Deal with it. */
8106 {
8109 }
8110 }
8113 {
8116 }
8118 {
8122 }
8124 {
8127 }
8129 /* Issue an error message if we didn't find a template. */
8131 {
8135 }
8138 /* Make sure it's a user visible template, if it was named by
8139 the user. */
8142 {
8144 {
8148 }
8150 }
8154 /* An alias that just changes the name of a template is equivalent to the
8155 other template, so if any of the arguments are pack expansions, strip
8156 the alias to avoid problems with a pack expansion passed to a non-pack
8157 alias template parameter (DR 1430). */
8162 {
8163 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8164 template arguments */
8166 tree parm;
8167 tree arglist2;
8168 tree outer;
8172 /* Consider an example where a template template parameter declared as
8174 template <class T, class U = std::allocator<T> > class TT
8176 The template parameter level of T and U are one level larger than
8177 of TT. To proper process the default argument of U, say when an
8178 instantiation `TT<int>' is seen, we need to build the full
8179 arguments containing {int} as the innermost level. Outer levels,
8180 available when not appearing as default template argument, can be
8181 obtained from the arguments of the enclosing template.
8183 Suppose that TT is later substituted with std::vector. The above
8184 instantiation is `TT<int, std::allocator<T> >' with TT at
8185 level 1, and T at level 2, while the template arguments at level 1
8186 becomes {std::vector} and the inner level 2 is {int}. */
8192 {
8193 /* This is an argument of the current template, so we haven't set
8194 DECL_CONTEXT yet. */
8195 tree relevant_template_parms;
8197 /* Parameter levels that are greater than the level of the given
8198 template template parm are irrelevant. */
8205 }
8211 complain,
8221 }
8222 else
8223 {
8225 tree gen_tmpl;
8226 tree type_decl;
8234 /* An error occurred while building the template TEMPL, and a
8235 diagnostic has most certainly been emitted for that
8236 already. Let's propagate that error. */
8245 {
8246 /* We've been given an incomplete set of template arguments.
8247 For example, given:
8249 template <class T> struct S1 {
8250 template <class U> struct S2 {};
8251 template <class U> struct S2<U*> {};
8252 };
8254 we will be called with an ARGLIST of `U*', but the
8255 TEMPLATE will be `template <class T> template
8256 <class U> struct S1<T>::S2'. We must fill in the missing
8257 arguments. */
8258 arglist
8260 arglist);
8262 }
8264 /* Now we should have enough arguments. */
8267 /* From here on, we're only interested in the most general
8268 template. */
8270 /* Calculate the BOUND_ARGS. These will be the args that are
8271 actually tsubst'd into the definition to create the
8272 instantiation. */
8274 complain,
8279 /* We were unable to bind the arguments. */
8282 /* In the scope of a template class, explicit references to the
8283 template class refer to the type of the template, not any
8284 instantiation of it. For example, in:
8286 template <class T> class C { void f(C<T>); }
8288 the `C<T>' is just the same as `C'. Outside of the
8289 class, however, such a reference is an instantiation. */
8293 /* comp_template_args is expensive, check it last. */
8295 arglist))
8298 /* If we already have this specialization, return it. */
8308 /* If the the template's constraints are not satisfied,
8309 then we cannot form a valid type.
8311 Note that the check is deferred until after the hash
8312 lookup. This prevents redundant checks on previously
8313 instantiated specializations. */
8315 {
8317 {
8320 }
8322 }
8326 /* If the deduced arguments are invalid, then the binding
8327 failed. */
8331 complain))
8338 {
8343 }
8353 /* Create the type. */
8355 {
8356 /* The user referred to a specialization of an alias
8357 template represented by GEN_TMPL.
8359 [temp.alias]/2 says:
8361 When a template-id refers to the specialization of an
8362 alias template, it is equivalent to the associated
8363 type obtained by substitution of its
8364 template-arguments for the template-parameters in the
8365 type-id of the alias template. */
8368 /* Note that the call above (by indirectly calling
8369 register_specialization in tsubst_decl) registers the
8370 TYPE_DECL representing the specialization of the alias
8371 template. So next time someone substitutes ARGLIST for
8372 the template parms into the alias template (GEN_TMPL),
8373 she'll get that TYPE_DECL back. */
8377 }
8379 {
8381 {
8390 }
8391 else
8392 {
8393 /* We don't want to call start_enum for this type, since
8394 the values for the enumeration constants may involve
8395 template parameters. And, no one should be interested
8396 in the enumeration constants for such a type. */
8399 }
8403 }
8405 {
8412 /* A local class. Make sure the decl gets registered properly. */
8417 /* This instantiation is another name for the primary
8418 template type. Set the TYPE_CANONICAL field
8419 appropriately. */
8422 /* Some of the template arguments require structural
8423 equality testing, so this template class requires
8424 structural equality testing. */
8426 }
8427 else
8430 /* If we called start_enum or pushtag above, this information
8431 will already be set up. */
8433 {
8440 }
8441 else
8445 {
8451 {
8454 }
8455 }
8459 {
8463 {
8464 tree attributes
8468 ;
8471 else
8476 }
8477 }
8479 /* Let's consider the explicit specialization of a member
8480 of a class template specialization that is implicitly instantiated,
8481 e.g.:
8482 template<class T>
8483 struct S
8484 {
8485 template<class U> struct M {}; //#0
8486 };
8488 template<>
8489 template<>
8490 struct S<int>::M<char> //#1
8491 {
8492 int i;
8493 };
8494 [temp.expl.spec]/4 says this is valid.
8496 In this case, when we write:
8497 S<int>::M<char> m;
8499 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8500 the one of #0.
8502 When we encounter #1, we want to store the partial instantiation
8503 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8505 For all cases other than this "explicit specialization of member of a
8506 class template", we just want to store the most general template into
8507 the CLASSTYPE_TI_TEMPLATE of M.
8509 This case of "explicit specialization of member of a class template"
8510 only happens when:
8511 1/ the enclosing class is an instantiation of, and therefore not
8512 the same as, the context of the most general template, and
8513 2/ we aren't looking at the partial instantiation itself, i.e.
8514 the innermost arguments are not the same as the innermost parms of
8515 the most general template.
8517 So it's only when 1/ and 2/ happens that we want to use the partial
8518 instantiation of the member template in lieu of its most general
8519 template. */
8523 /* the enclosing class must be an instantiation... */
8526 {
8527 tree partial_inst_args;
8530 partial_inst_args =
8536 use_partial_inst_tmpl =
8537 /*...and we must not be looking at the partial instantiation
8538 itself. */
8540 partial_inst_args);
8541 }
8544 /* This case is easy; there are no member templates involved. */
8546 else
8547 {
8548 /* This is a full instantiation of a member template. Find
8549 the partial instantiation of which this is an instance. */
8551 /* Temporarily reduce by one the number of levels in the ARGLIST
8552 so as to avoid comparing the last set of arguments. */
8556 /* FOUND is either a proper class type, or an alias
8557 template specialization. In the later case, it's a
8558 TYPE_DECL, resulting from the substituting of arguments
8559 for parameters in the TYPE_DECL of the alias template
8560 done earlier. So be careful while getting the template
8561 of FOUND. */
8565 }
8567 // Build template info for the new specialization.
8576 /* Note this use of the partial instantiation so we can check it
8577 later in maybe_process_partial_specialization. */
8584 /* Now that the type has been registered on the instantiations
8585 list, we set up the enumerators. Because the enumeration
8586 constants may involve the enumeration type itself, we make
8587 sure to register the type first, and then create the
8588 constants. That way, doing tsubst_expr for the enumeration
8589 constants won't result in recursive calls here; we'll find
8590 the instantiation and exit above. */
8594 /* If the type makes use of template parameters, the
8595 code that generates debugging information will crash. */
8598 /* Possibly limit visibility based on template args. */
8605 }
8606 }
8608 /* Wrapper for lookup_template_class_1. */
8610 tree
8613 {
8614 tree ret;
8620 }
8622 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8624 tree
8626 {
8627 /* The type of the expression is NULL_TREE since the template-id could refer
8628 to an explicit or partial specialization. */
8631 /* Except that concepts are always bool. */
8634 }
8636 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8638 tree
8640 {
8644 /* We never want to return a VAR_DECL for a variable concept, since they
8645 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8659 {
8661 {
8664 }
8666 }
8668 /* If a template-id refers to a specialization of a variable
8669 concept, then the expression is true if and only if the
8670 concept's constraints are satisfied by the given template
8671 arguments.
8673 NOTE: This is an extension of Concepts Lite TS that
8674 allows constraints to be used in expressions. */
8676 {
8679 }
8682 }
8683 \f
8684 struct pair_fn_data
8685 {
8686 tree_fn_t fn;
8688 /* True when we should also visit template parameters that occur in
8689 non-deduced contexts. */
8692 };
8694 /* Called from for_each_template_parm via walk_tree. */
8696 static tree
8698 {
8705 #define WALK_SUBTREE(NODE) \
8706 do \
8707 { \
8708 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
8709 pfd->include_nondeduced_p); \
8710 if (result) goto out; \
8711 } \
8712 while (0)
8719 {
8723 /* Fall through. */
8729 else
8739 /* Since we're not going to walk subtrees, we have to do this
8740 explicitly here. */
8742 /* Fall through. */
8745 /* Check the return type. */
8748 /* Check the parameter types. Since default arguments are not
8749 instantiated until they are needed, the TYPE_ARG_TYPES may
8750 contain expressions that involve template parameters. But,
8751 no-one should be looking at them yet. And, once they're
8752 instantiated, they don't contain template parameters, so
8753 there's no point in looking at them then, either. */
8754 {
8755 tree parm;
8760 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8761 want walk_tree walking into them itself. */
8763 }
8779 /* Fall through. */
8791 /* Record template parameters such as `T' inside `TT<T>'. */
8793 /* Fall through. */
8805 /* A template template parameter is encountered. */
8809 /* Already substituted template template parameter */
8826 /* If there's no type, then this thing must be some expression
8827 involving template parameters. */
8849 }
8851 #undef WALK_SUBTREE
8853 /* We didn't find any template parameters we liked. */
8854 out:
8856 }
8858 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8859 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8860 call FN with the parameter and the DATA.
8861 If FN returns nonzero, the iteration is terminated, and
8862 for_each_template_parm returns 1. Otherwise, the iteration
8863 continues. If FN never returns a nonzero value, the value
8864 returned by for_each_template_parm is 0. If FN is NULL, it is
8865 considered to be the function which always returns 1.
8867 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8868 parameters that occur in non-deduced contexts. When false, only
8869 visits those template parameters that can be deduced. */
8871 static tree
8875 {
8877 tree result;
8879 /* Set up. */
8884 /* Walk the tree. (Conceptually, we would like to walk without
8885 duplicates, but for_each_template_parm_r recursively calls
8886 for_each_template_parm, so we would need to reorganize a fair
8887 bit to use walk_tree_without_duplicates, so we keep our own
8888 visited list.) */
8891 else
8894 for_each_template_parm_r,
8898 /* Clean up. */
8900 {
8903 }
8906 }
8908 /* Returns true if T depends on any template parameter. */
8910 int
8912 {
8942 else
8943 {
8946 }
8951 }
8953 /* Returns true iff current_function_decl is an incompletely instantiated
8954 template. Useful instead of processing_template_decl because the latter
8955 is set to 0 during instantiate_non_dependent_expr. */
8957 bool
8959 {
8968 }
8970 /* Returns true if T depends on any template parameter with level LEVEL. */
8972 bool
8974 {
8977 }
8979 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8980 ill-formed translation unit, i.e. a variable or function that isn't
8981 usable in a constant expression. */
8985 {
8989 }
8991 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8992 neglectable and instantiated from within an erroneous instantiation. */
8994 static bool
8996 {
9007 }
9015 /* We're starting to instantiate D; record the template instantiation context
9016 for diagnostics and to restore it later. */
9018 bool
9020 {
9022 }
9024 /* We're starting to instantiate D; record the template instantiation context
9025 at LOC for diagnostics and to restore it later. */
9027 bool
9029 {
9033 {
9035 "template instantiation depth exceeds maximum of %d"
9037 max_tinst_depth);
9039 }
9041 /* If the current instantiation caused problems, don't let it instantiate
9042 anything else. Do allow deduction substitution and decls usable in
9043 constant expressions. */
9060 }
9062 /* We're done instantiating this template; return to the instantiation
9063 context. */
9065 void
9067 {
9068 /* Restore the filename and line number stashed away when we started
9069 this instantiation. */
9073 }
9075 /* We're instantiating a deferred template; restore the template
9076 instantiation context in which the instantiation was requested, which
9077 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9079 static tree
9081 {
9093 }
9095 /* Returns the TINST_LEVEL which gives the original instantiation
9096 context. */
9100 {
9106 }
9108 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9109 vector of template arguments, as for tsubst.
9111 Returns an appropriate tsubst'd friend declaration. */
9113 static tree
9115 {
9116 tree new_friend;
9121 /* This was a friend declared with an explicit template
9122 argument list, e.g.:
9124 friend void f<>(T);
9126 to indicate that f was a template instantiation, not a new
9127 function declaration. Now, we have to figure out what
9128 instantiation of what template. */
9129 {
9131 tree new_args;
9132 tree tmpl;
9135 /* Friend functions are looked up in the containing namespace scope.
9136 We must enter that scope, to avoid finding member functions of the
9137 current class with same name. */
9152 tsk_none);
9154 }
9158 /* The NEW_FRIEND will look like an instantiation, to the
9159 compiler, but is not an instantiation from the point of view of
9160 the language. For example, we might have had:
9162 template <class T> struct S {
9163 template <class U> friend void f(T, U);
9164 };
9166 Then, in S<int>, template <class U> void f(int, U) is not an
9167 instantiation of anything. */
9173 {
9177 }
9179 /* The mangled name for the NEW_FRIEND is incorrect. The function
9180 is not a template instantiation and should not be mangled like
9181 one. Therefore, we forget the mangling here; we'll recompute it
9182 later if we need it. */
9184 {
9187 }
9190 {
9191 tree old_decl;
9192 tree new_friend_template_info;
9193 tree new_friend_result_template_info;
9194 tree ns;
9197 /* We must save some information from NEW_FRIEND before calling
9198 duplicate decls since that function will free NEW_FRIEND if
9199 possible. */
9201 new_friend_is_defn =
9206 {
9207 /* This declaration is a `primary' template. */
9210 new_friend_result_template_info
9212 }
9213 else
9216 /* Make the init_value nonzero so pushdecl knows this is a defn. */
9220 /* Inside pushdecl_namespace_level, we will push into the
9221 current namespace. However, the friend function should go
9222 into the namespace of the template. */
9232 {
9233 /* This new friend declaration matched an existing
9234 declaration. For example, given:
9236 template <class T> void f(T);
9237 template <class U> class C {
9238 template <class T> friend void f(T) {}
9239 };
9241 the friend declaration actually provides the definition
9242 of `f', once C has been instantiated for some type. So,
9243 old_decl will be the out-of-class template declaration,
9244 while new_friend is the in-class definition.
9246 But, if `f' was called before this point, the
9247 instantiation of `f' will have DECL_TI_ARGS corresponding
9248 to `T' but not to `U', references to which might appear
9249 in the definition of `f'. Previously, the most general
9250 template for an instantiation of `f' was the out-of-class
9251 version; now it is the in-class version. Therefore, we
9252 run through all specialization of `f', adding to their
9253 DECL_TI_ARGS appropriately. In particular, they need a
9254 new set of outer arguments, corresponding to the
9255 arguments for this class instantiation.
9257 The same situation can arise with something like this:
9259 friend void f(int);
9260 template <class T> class C {
9261 friend void f(T) {}
9262 };
9264 when `C<int>' is instantiated. Now, `f(int)' is defined
9265 in the class. */
9268 /* On the other hand, if the in-class declaration does
9269 *not* provide a definition, then we don't want to alter
9270 existing definitions. We can just leave everything
9271 alone. */
9272 ;
9273 else
9274 {
9278 /* Overwrite whatever template info was there before, if
9279 any, with the new template information pertaining to
9280 the declaration. */
9284 {
9285 /* We should have called reregister_specialization in
9286 duplicate_decls. */
9291 /* Instantiate it if the global has already been used. */
9295 }
9296 else
9297 {
9298 tree t;
9300 /* Indicate that the old function template is a partial
9301 instantiation. */
9309 /* Reassign any specializations already in the hash table
9310 to the new more general template, and add the
9311 additional template args. */
9315 {
9317 spec_entry elt;
9329 register_specialization
9332 }
9334 }
9335 }
9337 /* The information from NEW_FRIEND has been merged into OLD_DECL
9338 by duplicate_decls. */
9340 }
9341 }
9342 else
9343 {
9347 /* In the code
9348 template <class T> class C {
9349 template <class U> friend void C1<U>::f (); // case 1
9350 friend void C2<T>::f (); // case 2
9351 };
9352 we only need to make sure CONTEXT is a complete type for
9353 case 2. To distinguish between the two cases, we note that
9354 CONTEXT of case 1 remains dependent type after tsubst while
9355 this isn't true for case 2. */
9365 {
9367 /* do_friend adds the TEMPLATE_DECL for any member friend
9368 template even if it isn't a member template, i.e.
9369 template <class T> friend A<T>::f();
9370 Look through it in that case. */
9374 /* Check to see that the declaration is really present, and,
9375 possibly obtain an improved declaration. */
9380 }
9381 }
9384 }
9386 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9387 template arguments, as for tsubst.
9389 Returns an appropriate tsubst'd friend type or error_mark_node on
9390 failure. */
9392 static tree
9394 {
9395 tree friend_type;
9396 tree tmpl;
9397 tree context;
9400 {
9403 }
9408 {
9411 else
9413 }
9415 /* Look for a class template declaration. We look for hidden names
9416 because two friend declarations of the same template are the
9417 same. For example, in:
9419 struct A {
9420 template <typename> friend class F;
9421 };
9422 template <typename> struct B {
9423 template <typename> friend class F;
9424 };
9426 both F templates are the same. */
9430 /* But, if we don't find one, it might be because we're in a
9431 situation like this:
9433 template <class T>
9434 struct S {
9435 template <class U>
9436 friend struct S;
9437 };
9439 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9440 for `S<int>', not the TEMPLATE_DECL. */
9442 {
9445 }
9448 {
9449 /* The friend template has already been declared. Just
9450 check to see that the declarations match, and install any new
9451 default parameters. We must tsubst the default parameters,
9452 of course. We only need the innermost template parameters
9453 because that is all that redeclare_class_template will look
9454 at. */
9457 {
9458 tree parms;
9459 location_t saved_input_location;
9469 }
9472 }
9473 else
9474 {
9475 /* The friend template has not already been declared. In this
9476 case, the instantiation of the template class will cause the
9477 injection of this template into the global scope. */
9482 /* The new TMPL is not an instantiation of anything, so we
9483 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9484 the new type because that is supposed to be the corresponding
9485 template decl, i.e., TMPL. */
9492 /* Inject this template into the global scope. */
9494 }
9497 {
9500 else
9502 }
9505 }
9507 /* Returns zero if TYPE cannot be completed later due to circularity.
9508 Otherwise returns one. */
9510 static int
9512 {
9522 else
9524 }
9528 /* Apply any attributes which had to be deferred until instantiation
9529 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9530 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9532 static void
9535 {
9537 tree t;
9542 {
9546 }
9549 {
9553 }
9554 else
9558 {
9563 {
9566 {
9573 {
9580 clauses
9584 else
9586 }
9587 /* If the first attribute argument is an identifier, don't
9588 pass it through tsubst. Attributes like mode, format,
9589 cleanup and several target specific attributes expect it
9590 unmodified. */
9593 {
9594 tree chain
9596 in_decl,
9601 chain);
9602 }
9604 {
9605 /* An attribute pack expansion. */
9607 tree pack = (tsubst_pack_expansion
9611 {
9615 }
9617 }
9618 else
9624 }
9625 else
9627 }
9630 }
9631 }
9633 /* Perform (or defer) access check for typedefs that were referenced
9634 from within the template TMPL code.
9635 This is a subroutine of instantiate_decl and instantiate_class_template.
9636 TMPL is the template to consider and TARGS is the list of arguments of
9637 that template. */
9639 static void
9641 {
9642 location_t saved_location;
9653 {
9665 /* Make access check error messages point to the location
9666 of the use of the typedef. */
9670 tf_warning_or_error);
9671 }
9673 }
9675 static tree
9677 {
9679 tree typedecl;
9680 tree pbinfo;
9681 tree base_list;
9683 tree fn_context;
9692 /* Figure out which template is being instantiated. */
9696 /* Determine what specialization of the original template to
9697 instantiate. */
9700 {
9703 }
9705 {
9706 /* This TYPE is actually an instantiation of a partial
9707 specialization. We replace the innermost set of ARGS with
9708 the arguments appropriate for substitution. For example,
9709 given:
9711 template <class T> struct S {};
9712 template <class T> struct S<T*> {};
9714 and supposing that we are instantiating S<int*>, ARGS will
9715 presently be {int*} -- but we need {int}. */
9718 }
9719 else
9720 {
9723 }
9725 /* If the template we're instantiating is incomplete, then clearly
9726 there's nothing we can do. */
9730 /* If we've recursively instantiated too many templates, stop. */
9734 /* Now we're really doing the instantiation. Mark the type as in
9735 the process of being defined. */
9738 /* We may be in the middle of deferred access check. Disable
9739 it now. */
9746 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9751 else
9752 {
9755 }
9756 /* Use #pragma pack from the template context. */
9762 /* Set the input location to the most specialized template definition.
9763 This is needed if tsubsting causes an error. */
9775 {
9778 /* Adjust visibility for template arguments. */
9780 }
9786 /* We should never instantiate a nested class before its enclosing
9787 class; we need to look up the nested class by name before we can
9788 instantiate it, and that lookup should instantiate the enclosing
9789 class. */
9795 {
9796 tree pbase_binfo;
9797 tree pushed_scope;
9800 /* We must enter the scope containing the type, as that is where
9801 the accessibility of types named in dependent bases are
9802 looked up from. */
9805 /* Substitute into each of the bases to determine the actual
9806 basetypes. */
9808 {
9809 tree base;
9815 {
9816 expanded_bases =
9823 }
9826 {
9828 /* Extract the already-expanded base class. */
9830 else
9831 /* Substitute to figure out the base class. */
9833 NULL_TREE);
9841 }
9842 }
9844 /* The list is now in reverse order; correct that. */
9849 }
9850 /* Now call xref_basetypes to set up all the base-class
9851 information. */
9859 /* Now that our base classes are set up, enter the scope of the
9860 class, so that name lookups into base classes, etc. will work
9861 correctly. This is precisely analogous to what we do in
9862 begin_class_definition when defining an ordinary non-template
9863 class, except we also need to push the enclosing classes. */
9866 /* Now members are processed in the order of declaration. */
9869 {
9873 {
9875 {
9876 /* Build new CLASSTYPE_NESTED_UTDS. */
9878 tree newtag;
9884 /* If the member is a class template, then -- even after
9885 substitution -- there may be dependent types in the
9886 template argument list for the class. We increment
9887 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9888 that function will assume that no types are dependent
9889 when outside of a template. */
9899 {
9903 /* Unfortunately, lookup_template_class sets
9904 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9905 instantiation (i.e., for the type of a member
9906 template class nested within a template class.)
9907 This behavior is required for
9908 maybe_process_partial_specialization to work
9909 correctly, but is not accurate in this case;
9910 the TAG is not an instantiation of anything.
9911 (The corresponding TEMPLATE_DECL is an
9912 instantiation, but the TYPE is not.) */
9915 /* Now, we call pushtag to put this NEWTAG into the scope of
9916 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9917 pushtag calling push_template_decl. We don't have to do
9918 this for enums because it will already have been done in
9919 tsubst_enum. */
9923 }
9924 }
9926 {
9927 /* Build new TYPE_METHODS. */
9928 tree r;
9937 /* Instantiate members marked with attribute used. */
9943 }
9946 /* A closure type for a lambda in a default argument for a
9947 member template. Ignore it; it will be instantiated with
9949 else
9950 {
9951 /* Build new TYPE_FIELDS. */
9953 {
9954 tree condition;
9957 condition =
9967 }
9969 {
9970 tree r;
9974 /* The file and line for this declaration, to
9975 assist in error message reporting. Since we
9976 called push_tinst_level above, we don't need to
9977 restore these. */
9987 {
9988 /* A capture pack became multiple fields. */
9991 }
9994 {
9998 {
9999 /* In [temp.inst]:
10001 [t]he initialization (and any associated
10002 side-effects) of a static data member does
10003 not occur unless the static data member is
10004 itself used in a way that requires the
10005 definition of the static data member to
10006 exist.
10008 Therefore, we do not substitute into the
10009 initialized for the static data member here. */
10010 finish_static_data_member_decl
10016 /* Instantiate members marked with attribute used. */
10019 }
10021 {
10022 /* Determine whether R has a valid type and can be
10023 completed later. If R is invalid, then its type
10024 is replaced by error_mark_node. */
10030 {
10033 }
10034 }
10036 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10037 such a thing will already have been added to the field
10038 list by tsubst_enum in finish_member_declaration in the
10039 CLASSTYPE_NESTED_UTDS case above. */
10043 {
10046 }
10047 }
10048 }
10049 }
10050 }
10051 else
10052 {
10055 {
10056 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10062 {
10063 /* template <class T> friend class C; */
10066 }
10068 {
10069 /* template <class T> friend class C::D; */
10075 }
10078 {
10079 /* This could be either
10081 friend class T::C;
10083 when dependent_type_p is false or
10085 template <class U> friend class T::C;
10087 otherwise. */
10090 /* Bump processing_template_decl for correct
10091 dependent_type_p calculation. */
10096 }
10099 {
10100 /* friend class C;
10102 where C hasn't been declared yet. Let's lookup name
10103 from namespace scope directly, bypassing any name that
10104 come from dependent base class. */
10107 /* The call to xref_tag_from_type does injection for friend
10108 classes. */
10110 friend_type =
10114 }
10116 /* friend class C<T>; */
10119 /* Otherwise it's
10121 friend class C;
10123 where C is already declared or
10125 friend class C<int>;
10127 We don't have to do anything in these cases. */
10130 /* Trick make_friend_class into realizing that the friend
10131 we're adding is a template, not an ordinary class. It's
10132 important that we use make_friend_class since it will
10133 perform some error-checking and output cross-reference
10134 information. */
10142 }
10143 else
10144 {
10145 /* Build new DECL_FRIENDLIST. */
10146 tree r;
10148 /* The file and line for this declaration, to
10149 assist in error message reporting. Since we
10150 called push_tinst_level above, we don't need to
10151 restore these. */
10155 {
10158 }
10163 {
10166 }
10167 }
10168 }
10169 }
10172 {
10173 /* Restore these before substituting into the lambda capture
10174 initializers. */
10177 }
10180 {
10183 {
10186 {
10187 /* Set function_depth to avoid garbage collection. */
10191 }
10193 /* We need to instantiate the capture list from the template
10194 after we've instantiated the closure members, but before we
10195 consider adding the conversion op. Also keep any captures
10196 that may have been added during instantiation of the op(). */
10198 tree tmpl_cap
10207 }
10208 else
10210 }
10212 /* Set the file and line number information to whatever is given for
10213 the class itself. This puts error messages involving generated
10214 implicit functions at a predictable point, and the same point
10215 that would be used for non-template classes. */
10222 /* We don't instantiate default arguments for member functions. 14.7.1:
10224 The implicit instantiation of a class template specialization causes
10225 the implicit instantiation of the declarations, but not of the
10226 definitions or default arguments, of the class member functions,
10227 member classes, static data members and member templates.... */
10229 /* Some typedefs referenced from within the template code need to be access
10230 checked at template instantiation time, i.e now. These types were
10231 added to the template at parsing time. Let's get those and perform
10232 the access checks then. */
10242 /* The vtable for a template class can be emitted in any translation
10243 unit in which the class is instantiated. When there is no key
10244 method, however, finish_struct_1 will already have added TYPE to
10245 the keyed_classes list. */
10250 }
10252 /* Wrapper for instantiate_class_template_1. */
10254 tree
10256 {
10257 tree ret;
10262 }
10264 static tree
10266 {
10267 tree r;
10273 else
10274 {
10281 }
10283 }
10285 /* Given a function parameter pack TMPL_PARM and some function parameters
10286 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10287 and set *SPEC_P to point at the next point in the list. */
10289 tree
10291 {
10292 /* Collect all of the extra "packed" parameters into an
10293 argument pack. */
10294 tree parmvec;
10295 tree parmtypevec;
10306 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10311 {
10314 }
10316 /* Build the argument packs. */
10323 }
10325 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10326 NONTYPE_ARGUMENT_PACK. */
10328 static tree
10330 {
10332 }
10334 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10335 pack expansion with no extra args, 2 if it has extra args, or 0
10336 if it is not a pack expansion. */
10338 static int
10340 {
10346 /* A decl pack is itself an expansion. */
10353 }
10356 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10358 static tree
10360 {
10367 }
10369 /* This is a subroutine of tsubst_pack_expansion.
10371 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10372 mechanism to store the (non complete list of) arguments of the
10373 substitution and return a non substituted pack expansion, in order
10374 to wait for when we have enough arguments to really perform the
10375 substitution. */
10377 static bool
10381 {
10382 /* If one pack has an expansion and another pack has a normal
10383 argument or if one pack has an empty argument and an another
10384 one hasn't then tsubst_pack_expansion cannot perform the
10385 substitution and need to fall back on the
10386 PACK_EXPANSION_EXTRA mechanism. */
10394 {
10397 parm_pack;
10399 {
10404 /* We can't substitute a pack expansion with extra args into
10405 our pattern. */
10409 else
10411 }
10415 }
10417 }
10419 /* [temp.variadic]/6 says that:
10421 The instantiation of a pack expansion [...]
10422 produces a list E1,E2, ..., En, where N is the number of elements
10423 in the pack expansion parameters.
10425 This subroutine of tsubst_pack_expansion produces one of these Ei.
10427 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10428 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10429 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10430 INDEX is the index 'i' of the element Ei to produce. ARGS,
10431 COMPLAIN, and IN_DECL are the same parameters as for the
10432 tsubst_pack_expansion function.
10434 The function returns the resulting Ei upon successful completion,
10435 or error_mark_node.
10437 Note that this function possibly modifies the ARGS parameter, so
10438 it's the responsibility of the caller to restore it. */
10440 static tree
10442 tree parm_packs,
10444 tree args /* This parm gets
10446 tsubst_flags_t complain,
10447 tree in_decl)
10448 {
10449 tree t;
10452 /* For each parameter pack, change the substitution of the parameter
10453 pack to the ith argument in its argument pack, then expand the
10454 pattern. */
10456 {
10461 ith_elem_is_expansion |=
10464 /* Select the Ith argument from the pack. */
10467 {
10469 {
10474 }
10475 else
10477 }
10478 else
10479 {
10484 {
10486 /* Update the corresponding argument. */
10488 }
10489 else
10490 /* Re-use the ARGUMENT_PACK_SELECT. */
10492 }
10494 }
10496 /* Substitute into the PATTERN with the (possibly altered)
10497 arguments. */
10499 /* Expanding a fixed parameter pack from
10500 coerce_template_parameter_pack. */
10505 {
10508 else
10511 }
10515 else
10518 /* If the Ith argument pack element is a pack expansion, then
10519 the Ith element resulting from the substituting is going to
10520 be a pack expansion as well. */
10525 }
10527 /* When the unexpanded parameter pack in a fold expression expands to an empty
10528 sequence, the value of the expression is as follows; the program is
10529 ill-formed if the operator is not listed in this table.
10531 * 1
10532 + 0
10533 & -1
10534 | 0
10535 && true
10536 || false
10537 , void() */
10539 tree
10541 {
10545 {
10562 }
10568 }
10570 /* Given a fold-expression T and a current LEFT and RIGHT operand,
10571 form an expression that combines the two terms using the
10572 operator of T. */
10574 static tree
10576 {
10580 // Handle compound assignment operators.
10585 {
10595 complain);
10596 }
10597 }
10599 /* Substitute ARGS into the pack of a fold expression T. */
10603 {
10605 }
10607 /* Substitute ARGS into the pack of a fold expression T. */
10611 {
10613 }
10615 /* Expand a PACK of arguments into a grouped as left fold.
10616 Given a pack containing elements A0, A1, ..., An and an
10617 operator @, this builds the expression:
10619 ((A0 @ A1) @ A2) ... @ An
10621 Note that PACK must not be empty.
10623 The operator is defined by the original fold expression T. */
10625 static tree
10627 {
10630 {
10633 }
10635 }
10637 /* Substitute into a unary left fold expression. */
10639 static tree
10641 tree in_decl)
10642 {
10648 else
10650 }
10652 /* Substitute into a binary left fold expression.
10654 Do ths by building a single (non-empty) vector of argumnts and
10655 building the expression from those elements. */
10657 static tree
10659 tree in_decl)
10660 {
10674 }
10676 /* Expand a PACK of arguments into a grouped as right fold.
10677 Given a pack containing elementns A0, A1, ..., and an
10678 operator @, this builds the expression:
10680 A0@ ... (An-2 @ (An-1 @ An))
10682 Note that PACK must not be empty.
10684 The operator is defined by the original fold expression T. */
10686 tree
10688 {
10689 // Build the expression.
10693 {
10696 }
10698 }
10700 /* Substitute into a unary right fold expression. */
10702 static tree
10704 tree in_decl)
10705 {
10711 else
10713 }
10715 /* Substitute into a binary right fold expression.
10717 Do ths by building a single (non-empty) vector of arguments and
10718 building the expression from those elements. */
10720 static tree
10722 tree in_decl)
10723 {
10738 }
10741 /* Substitute ARGS into T, which is an pack expansion
10742 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
10743 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
10744 (if only a partial substitution could be performed) or
10745 ERROR_MARK_NODE if there was an error. */
10746 tree
10748 tree in_decl)
10749 {
10750 tree pattern;
10754 tree result;
10762 /* Add in any args remembered from an earlier partial instantiation. */
10767 /* Determine the argument packs that will instantiate the parameter
10768 packs used in the expansion expression. While we're at it,
10769 compute the number of arguments to be expanded and make sure it
10770 is consistent. */
10773 {
10780 {
10784 else
10787 }
10789 {
10790 /* We know we have correct local_specializations if this
10791 expansion is at function scope, or if we're dealing with a
10792 local parameter in a requires expression; for the latter,
10793 tsubst_requires_expr set it up appropriately. */
10796 else
10797 {
10798 /* We can't rely on local_specializations for a parameter
10799 name used later in a function declaration (such as in a
10800 late-specified return type). Even if it exists, it might
10801 have the wrong value for a recursive call. Just make a
10802 dummy decl, since it's only used for its type. */
10805 /* Partial instantiation of the parm_pack, we can't build
10806 up an argument pack yet. */
10808 else
10811 }
10812 }
10815 else
10816 {
10822 }
10829 /* This can only happen if we forget to expand an argument
10830 pack somewhere else. Just return an error, silently. */
10831 {
10835 }
10838 {
10842 /* Don't bother trying to do a partial substitution with
10843 incomplete packs; we'll try again after deduction. */
10850 {
10856 pattern);
10857 else
10860 pattern);
10862 }
10864 /* Keep track of the parameter packs and their corresponding
10865 argument packs. */
10868 }
10869 else
10870 {
10871 /* We can't substitute for this parameter pack. We use a flag as
10872 well as the missing_level counter because function parameter
10873 packs don't have a level. */
10875 }
10876 }
10878 /* If the expansion is just T..., return the matching argument pack, unless
10879 we need to call convert_from_reference on all the elements. This is an
10880 important optimization; see c++/68422. */
10883 {
10885 /* Types need no adjustment, nor does sizeof..., and if we still have
10886 some pack expansion args we won't do anything yet. */
10891 /* Also optimize expression pack expansions if we can tell that the
10892 elements won't have reference type. */
10898 /* Otherwise use the normal path so we get convert_from_reference. */
10899 }
10901 /* We cannot expand this expansion expression, because we don't have
10902 all of the argument packs we need. */
10904 {
10905 /* We got some full packs, but we can't substitute them in until we
10906 have values for all the packs. So remember these until then. */
10911 }
10913 {
10914 /* There were no real arguments, we're just replacing a parameter
10915 pack with another version of itself. Substitute into the
10916 pattern and return a PACK_EXPANSION_*. The caller will need to
10917 deal with that. */
10921 else
10925 }
10930 {
10931 /* We're in a late-specified return type, so create our own local
10932 specializations map; the current map is either NULL or (in the
10933 case of recursive unification) might have bindings that we don't
10934 want to use or alter. */
10937 }
10939 /* For each argument in each argument pack, substitute into the
10940 pattern. */
10943 {
10945 i,
10947 in_decl);
10950 {
10953 }
10954 }
10956 /* Update ARGS to restore the substitution from parameter packs to
10957 their argument packs. */
10959 {
10965 else
10966 {
10974 /* Update the corresponding argument. */
10978 else
10980 }
10981 }
10984 {
10987 }
10990 }
10992 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
10993 TMPL. We do this using DECL_PARM_INDEX, which should work even with
10994 parameter packs; all parms generated from a function parameter pack will
10995 have the same DECL_PARM_INDEX. */
10997 tree
10999 {
11001 tree patparm;
11004 {
11010 }
11011 else
11012 {
11017 }
11020 }
11022 /* Substitute ARGS into the vector or list of template arguments T. */
11024 static tree
11026 {
11038 {
11040 tree new_arg;
11045 {
11046 /* Substitute into an expansion expression. */
11050 /* Add to the expanded length adjustment the number of
11051 expanded arguments. We subtract one from this
11052 measurement, because the argument pack expression
11053 itself is already counted as 1 in
11054 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11055 the argument pack is empty. */
11057 }
11059 {
11060 /* Substitute into each of the arguments. */
11066 new_arg,
11080 }
11081 }
11082 else
11091 }
11096 /* Make space for the expanded arguments coming from template
11097 argument packs. */
11099 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11100 arguments for a member template.
11101 In that case each TREE_VEC in ORIG_T represents a level of template
11102 arguments, and ORIG_T won't carry any non defaulted argument count.
11103 It will rather be the nested TREE_VECs that will carry one.
11104 In other words, ORIG_T carries a non defaulted argument count only
11105 if it doesn't contain any nested TREE_VEC. */
11107 {
11111 }
11113 {
11117 {
11120 /* Now expand the template argument pack "in place". */
11123 }
11124 else
11125 {
11127 out++;
11128 }
11129 }
11132 }
11134 /* Return the result of substituting ARGS into the template parameters
11135 given by PARMS. If there are m levels of ARGS and m + n levels of
11136 PARMS, then the result will contain n levels of PARMS. For
11137 example, if PARMS is `template <class T> template <class U>
11138 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11139 result will be `template <int*, double, class V>'. */
11141 static tree
11143 {
11147 /* When substituting into a template, we must set
11148 PROCESSING_TEMPLATE_DECL as the template parameters may be
11149 dependent if they are based on one-another, and the dependency
11150 predicates are short-circuit outside of templates. */
11157 {
11158 tree new_vec =
11163 {
11164 tree tuple;
11176 }
11182 }
11187 }
11189 /* Return the result of substituting ARGS into one template parameter
11190 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11191 parameter and which TREE_PURPOSE is the default argument of the
11192 template parameter. */
11194 static tree
11196 {
11217 }
11219 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11220 type T. If T is not an aggregate or enumeration type, it is
11221 handled as if by tsubst. IN_DECL is as for tsubst. If
11222 ENTERING_SCOPE is nonzero, T is the context for a template which
11223 we are presently tsubst'ing. Return the substituted value. */
11225 static tree
11227 tree args,
11228 tsubst_flags_t complain,
11229 tree in_decl,
11231 {
11236 {
11241 /* Else fall through. */
11245 {
11246 tree argvec;
11247 tree context;
11248 tree r;
11252 /* In "sizeof(X<I>)" we need to evaluate "I". */
11258 /* First, determine the context for the type we are looking
11259 up. */
11262 {
11265 /* If context is a nested class inside a class template,
11266 it may still need to be instantiated (c++/33959). */
11268 }
11270 /* Then, figure out what arguments are appropriate for the
11271 type we are trying to find. For example, given:
11273 template <class T> struct S;
11274 template <class T, class U> void f(T, U) { S<U> su; }
11276 and supposing that we are instantiating f<int, double>,
11277 then our ARGS will be {int, double}, but, when looking up
11278 S we only want {double}. */
11283 else
11284 {
11288 }
11294 }
11295 else
11296 /* This is not a template type, so there's nothing to do. */
11301 }
11302 }
11304 /* Substitute into the default argument ARG (a default argument for
11305 FN), which has the indicated TYPE. */
11307 tree
11309 {
11314 /* This can happen in invalid code. */
11318 /* This default argument came from a template. Instantiate the
11319 default argument here, not in tsubst. In the case of
11320 something like:
11322 template <class T>
11323 struct S {
11324 static T t();
11325 void f(T = t());
11326 };
11328 we must be careful to do name lookup in the scope of S<T>,
11329 rather than in the current class. */
11331 /* The "this" pointer is not valid in a default argument. */
11333 {
11338 }
11341 /* The default argument expression may cause implicitly defined
11342 member functions to be synthesized, which will result in garbage
11343 collection. We must treat this situation as if we were within
11344 the body of function so as to avoid collecting live data on the
11345 stack. */
11353 /* Restore the "this" pointer. */
11355 {
11358 }
11365 /* Make sure the default argument is reasonable. */
11371 }
11373 /* Substitute into all the default arguments for FN. */
11375 static void
11377 {
11378 tree arg;
11379 tree tmpl_args;
11383 /* If this function is not yet instantiated, we certainly don't need
11384 its default arguments. */
11387 /* Don't do this again for clones. */
11392 arg;
11398 complain);
11399 }
11401 /* Substitute the ARGS into the T, which is a _DECL. Return the
11402 result of the substitution. Issue error and warning messages under
11403 control of COMPLAIN. */
11405 static tree
11407 {
11408 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11409 location_t saved_loc;
11414 /* Set the filename and linenumber to improve error-reporting. */
11419 {
11421 {
11422 /* We can get here when processing a member function template,
11423 member class template, or template template parameter. */
11425 tree spec;
11426 tree tmpl_args;
11427 tree full_args;
11430 {
11431 /* Template template parameter is treated here. */
11435 /* If we get a real template back, return it. This can happen in
11436 the context of most_specialized_partial_spec. */
11439 else
11440 /* The new TEMPLATE_DECL was built in
11441 reduce_template_parm_level. */
11444 }
11446 /* We might already have an instance of this template.
11447 The ARGS are for the surrounding class type, so the
11448 full args contain the tsubst'd args for the context,
11449 plus the innermost args from the template decl. */
11453 /* Because this is a template, the arguments will still be
11454 dependent, even after substitution. If
11455 PROCESSING_TEMPLATE_DECL is not set, the dependency
11456 predicates will short-circuit. */
11464 /* If this is a default template template argument,
11465 tsubst might not have changed anything. */
11472 {
11475 }
11477 /* Make a new template decl. It will be similar to the
11478 original, but will record the current template arguments.
11479 We also create a new function declaration, which is just
11480 like the old one, but points to this new template, rather
11481 than the old one. */
11486 // Build new template info linking to the original template decl.
11491 {
11492 tree new_type;
11500 /* For a partial specialization, we need to keep pointing to
11501 the primary template. */
11507 }
11508 else
11509 {
11510 tree new_decl;
11522 }
11528 /* The template parameters for this new template are all the
11529 template parameters for the old template, except the
11530 outermost level of parameters. */
11533 complain);
11539 /* Record this non-type partial instantiation. */
11543 }
11547 {
11548 tree ctx;
11551 tree gen_tmpl;
11552 tree type;
11557 /* Nobody should be tsubst'ing into non-template functions. */
11561 {
11562 tree spec;
11565 /* If T is not dependent, just return it. We have to
11566 increment PROCESSING_TEMPLATE_DECL because
11567 value_dependent_expression_p assumes that nothing is
11568 dependent when PROCESSING_TEMPLATE_DECL is zero. */
11575 /* Calculate the most general template of which R is a
11576 specialization, and the complete set of arguments used to
11577 specialize R. */
11580 (DECL_TEMPLATE_RESULT
11586 /* Check to see if we already have this specialization. */
11591 {
11594 }
11596 /* We can see more levels of arguments than parameters if
11597 there was a specialization of a member template, like
11598 this:
11600 template <class T> struct S { template <class U> void f(); }
11601 template <> template <class U> void S<int>::f(U);
11603 Here, we'll be substituting into the specialization,
11604 because that's where we can find the code we actually
11605 want to generate, but we'll have enough arguments for
11606 the most general template.
11608 We also deal with the peculiar case:
11610 template <class T> struct S {
11611 template <class U> friend void f();
11612 };
11613 template <class U> void f() {}
11614 template S<int>;
11615 template void f<double>();
11617 Here, the ARGS for the instantiation of will be {int,
11618 double}. But, we only need as many ARGS as there are
11619 levels of template parameters in CODE_PATTERN. We are
11620 careful not to get fooled into reducing the ARGS in
11621 situations like:
11623 template <class T> struct S { template <class U> void f(U); }
11624 template <class T> template <> void S<T>::f(int) {}
11626 which we can spot because the pattern will be a
11627 specialization in this case. */
11629 parms_depth =
11634 }
11635 else
11636 {
11637 /* This special case arises when we have something like this:
11639 template <class T> struct S {
11640 friend void f<int>(int, double);
11641 };
11643 Here, the DECL_TI_TEMPLATE for the friend declaration
11644 will be an IDENTIFIER_NODE. We are being called from
11645 tsubst_friend_function, and we want only to create a
11646 new decl (R) with appropriate types so that we can call
11647 determine_specialization. */
11649 }
11652 {
11655 else
11659 }
11660 else
11661 {
11664 }
11669 /* If we hit excessive deduction depth, the type is bogus even if
11670 it isn't error_mark_node, so don't build a decl. */
11674 /* We do NOT check for matching decls pushed separately at this
11675 point, as they may not represent instantiations of this
11676 template, and in any case are considered separate under the
11677 discrete model. */
11681 /* Clear out the mangled name and RTL for the instantiation. */
11684 /* Leave DECL_INITIAL set on deleted instantiations. */
11689 /* OpenMP UDRs have the only argument a reference to the declared
11690 type. We want to diagnose if the declared type is a reference,
11691 which is invalid, but as references to references are usually
11692 quietly merged, diagnose it here. */
11694 {
11695 tree argtype
11700 "reference type %qT in "
11704 argtype);
11705 }
11708 /* Type-conversion operator. Reconstruct the name, in
11709 case it's the name of one of the template's parameters. */
11719 /* If this is an instantiation of a function with internal
11720 linkage, we already know what object file linkage will be
11721 assigned to the instantiation. */
11730 /* We'll re-clone as appropriate in instantiate_template. */
11733 /* If we aren't complaining now, return on error before we register
11734 the specialization so that we'll complain eventually. */
11740 /* When instantiating a constrained member, substitute
11741 into the constraints to create a new constraint. */
11744 {
11747 }
11749 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
11750 this in the special friend case mentioned above where
11751 GEN_TMPL is NULL. */
11753 {
11758 tree new_r
11761 /* We instantiated this while substituting into
11762 the type earlier (template/friend54.C). */
11765 /* We're not supposed to instantiate default arguments
11766 until they are called, for a template. But, for a
11767 declaration like:
11769 template <class T> void f ()
11770 { extern void g(int i = T()); }
11772 we should do the substitution when the template is
11773 instantiated. We handle the member function case in
11774 instantiate_class_template since the default arguments
11775 might refer to other members of the class. */
11780 }
11781 else
11784 /* Copy the list of befriending classes. */
11788 {
11792 in_decl);
11793 }
11796 {
11802 /* If this is an instantiation of a member template, clone it.
11803 If it isn't, that'll be handled by
11804 clone_constructors_and_destructors. */
11807 }
11818 /* Possibly limit visibility based on template args. */
11821 {
11825 }
11833 }
11837 {
11845 {
11846 /* If there is a local specialization that isn't a
11847 parameter pack, it means that we're doing a "simple"
11848 substitution from inside tsubst_pack_expansion. Just
11849 return the local specialization (which will be a single
11850 parm). */
11857 /* Expand the TYPE_PACK_EXPANSION that provides the types for
11858 the parameters in this function parameter pack. */
11862 {
11865 /* Zero-length parameter packs are boring. Just substitute
11866 into the chain. */
11870 }
11871 else
11872 {
11873 /* All we did was update the type. Make a note of that. */
11876 }
11877 }
11879 /* Loop through all of the parameters we'll build. When T is
11880 a function parameter pack, LEN is the number of expanded
11881 types in EXPANDED_TYPES; otherwise, LEN is 1. */
11884 {
11891 /* We're on the Ith parameter of the function parameter
11892 pack. */
11893 {
11894 /* Get the Ith type. */
11897 /* Rename the parameter to include the index. */
11900 }
11902 /* We're dealing with a normal parameter. */
11910 {
11913 else
11916 }
11926 /* Keep track of the first new parameter we
11927 generate. That's what will be returned to the
11928 caller. */
11932 /* Build a proper chain of parameters when substituting
11933 into a function parameter pack. */
11936 }
11938 /* If cp_unevaluated_operand is set, we're just looking for a
11939 single dummy parameter, so don't keep going. */
11944 /* FIRST_R contains the start of the chain we've built. */
11946 }
11950 {
11957 {
11958 /* This field is a lambda capture pack. Return a TREE_VEC of
11959 the expanded fields to instantiate_class_template_1 and
11960 store them in the specializations hash table as a
11961 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11965 {
11968 }
11969 else
11970 {
11971 /* All we did was update the type. Make a note of that. */
11974 }
11975 }
11978 {
11981 {
11985 }
11995 /* For bit-fields, DECL_INITIAL gives the number of bits. For
11996 non-bit-fields DECL_INITIAL is a non-static data member
11997 initializer, which gets deferred instantiation. */
12003 {
12004 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12005 NSDMI in perform_member_init. Still set DECL_INITIAL
12006 so that we know there is one. */
12011 }
12012 /* We don't have to set DECL_CONTEXT here; it is set by
12013 finish_member_declaration. */
12021 }
12024 {
12032 }
12033 }
12037 /* We reach here only for member using decls. We also need to check
12038 uses_template_parms because DECL_DEPENDENT_P is not set for a
12039 using-declaration that designates a member of the current
12040 instantiation (c++/53549). */
12043 {
12050 else
12051 {
12054 }
12055 }
12056 else
12057 {
12060 }
12065 {
12068 tree spec;
12070 tree ctx;
12079 {
12080 /* If this is the canonical decl, we don't have to
12081 mess with instantiations, and often we can't (for
12082 typename, template type parms and such). Note that
12083 TYPE_NAME is not correct for the above test if
12084 we've copied the type for a typedef. */
12090 }
12092 /* Check to see if we already have the specialization we
12093 need. */
12096 {
12097 /* T is a static data member or namespace-scope entity.
12098 We have to substitute into namespace-scope variables
12099 (not just variable templates) because of cases like:
12101 template <class T> void f() { extern T t; }
12103 where the entity referenced is not known until
12104 instantiation time. */
12108 {
12110 complain,
12112 /* If CTX is unchanged, then T is in fact the
12113 specialization we want. That situation occurs when
12114 referencing a static data member within in its own
12115 class. We can use pointer equality, rather than
12116 same_type_p, because DECL_CONTEXT is always
12117 canonical... */
12119 /* ... unless T is a member template; in which
12120 case our caller can be willing to create a
12121 specialization of that template represented
12122 by T. */
12126 }
12129 {
12134 argvec = (coerce_innermost_template_parms
12142 }
12143 }
12144 else
12145 {
12146 /* A local variable. */
12148 /* Subsequent calls to pushdecl will fill this in. */
12151 }
12152 /* If we already have the specialization we need, there is
12153 nothing more to do. */
12155 {
12158 }
12160 /* Create a new node for the specialization we need. */
12163 {
12166 else
12173 }
12175 {
12176 /* Even if the original location is out of scope, the
12177 newly substituted one is not. */
12184 {
12185 /* It may seem that this case cannot occur, since:
12187 typedef void f();
12188 void g() { f x; }
12190 declares a function, not a variable. However:
12192 typedef void f();
12193 template <typename T> void g() { T t; }
12194 template void g<f>();
12196 is an attempt to declare a variable with function
12197 type. */
12199 /* R is not yet sufficiently initialized, so we
12200 just use its name. */
12203 }
12205 /* Wait until cp_finish_decl to set this again, to handle
12206 circular dependency (template/instantiate6.C). */
12211 {
12216 {
12219 }
12221 }
12225 }
12231 /* Clear out the mangled name and RTL for the instantiation. */
12235 /* The initializer must not be expanded until it is required;
12236 see [temp.inst]. */
12242 {
12243 /* Possibly limit visibility based on template args. */
12246 {
12250 }
12252 }
12255 {
12256 /* A static data member declaration is always marked
12257 external when it is declared in-class, even if an
12258 initializer is present. We mimic the non-template
12259 processing here. */
12267 }
12277 /* Preserve a typedef that names a type. */
12279 {
12283 /* An alias template specialization can be dependent
12284 even if its underlying type is not. */
12286 }
12289 }
12294 }
12295 #undef RETURN
12297 out:
12298 /* Restore the file and line information. */
12302 }
12304 /* Substitute into the ARG_TYPES of a function type.
12305 If END is a TREE_CHAIN, leave it and any following types
12306 un-substituted. */
12308 static tree
12310 tree args,
12311 tree end,
12312 tsubst_flags_t complain,
12313 tree in_decl)
12314 {
12315 tree remaining_arg_types;
12319 tree default_arg;
12330 {
12331 /* For a pack expansion, perform substitution on the
12332 entire expression. Later on, we'll handle the arguments
12333 one-by-one. */
12338 /* So that we'll spin through the parameters, one by one. */
12340 else
12341 {
12342 /* We only partially substituted into the parameter
12343 pack. Our type is TYPE_PACK_EXPANSION. */
12346 }
12347 }
12360 {
12362 {
12366 }
12368 }
12369 /* DR 657. */
12373 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12374 top-level qualifiers as required. */
12377 /* We do not substitute into default arguments here. The standard
12378 mandates that they be instantiated only when needed, which is
12379 done in build_over_call. */
12383 {
12384 /* We've instantiated a template before its default arguments
12385 have been parsed. This can happen for a nested template
12386 class, and is not an error unless we require the default
12387 argument in a call of this function. */
12388 remaining_arg_types =
12391 }
12392 else
12393 remaining_arg_types =
12395 }
12398 }
12400 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12401 *not* handle the exception-specification for FNTYPE, because the
12402 initial substitution of explicitly provided template parameters
12403 during argument deduction forbids substitution into the
12404 exception-specification:
12406 [temp.deduct]
12408 All references in the function type of the function template to the
12409 corresponding template parameters are replaced by the specified tem-
12410 plate argument values. If a substitution in a template parameter or
12411 in the function type of the function template results in an invalid
12412 type, type deduction fails. [Note: The equivalent substitution in
12413 exception specifications is done only when the function is instanti-
12414 ated, at which point a program is ill-formed if the substitution
12415 results in an invalid type.] */
12417 static tree
12419 tree args,
12420 tsubst_flags_t complain,
12421 tree in_decl)
12422 {
12423 tree return_type;
12425 tree fntype;
12427 /* The TYPE_CONTEXT is not used for function/method types. */
12430 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12431 failure. */
12435 {
12436 /* Substitute the argument types. */
12448 {
12449 /* DR 1207: 'this' is in scope in the trailing return type. */
12451 }
12453 /* Substitute the return type. */
12457 {
12460 }
12461 }
12462 else
12463 /* Substitute the return type. */
12468 /* DR 486 clarifies that creation of a function type with an
12469 invalid return type is a deduction failure. */
12472 {
12474 {
12477 else
12479 }
12481 }
12482 /* And DR 657. */
12487 {
12488 /* Substitute the argument types. */
12493 }
12495 /* Construct a new type node and return it. */
12497 {
12502 }
12503 else
12504 {
12506 /* Don't pick up extra function qualifiers from the basetype. */
12509 {
12510 /* [temp.deduct]
12512 Type deduction may fail for any of the following
12513 reasons:
12515 -- Attempting to create "pointer to member of T" when T
12516 is not a class type. */
12519 r);
12521 }
12526 }
12533 }
12535 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12536 ARGS into that specification, and return the substituted
12537 specification. If there is no specification, return NULL_TREE. */
12539 static tree
12541 tree args,
12542 tsubst_flags_t complain,
12543 tree in_decl,
12545 {
12546 tree specs;
12547 tree new_specs;
12552 {
12553 /* A noexcept-specifier. */
12558 {
12559 /* Defer instantiation of noexcept-specifiers to avoid
12560 excessive instantiations (c++/49107). */
12563 {
12564 /* We already partially instantiated this member template,
12565 so combine the new args with the old. */
12570 }
12571 else
12572 {
12575 }
12576 }
12577 else
12578 new_specs = tsubst_copy_and_build
12582 }
12584 {
12587 else
12589 {
12590 tree spec;
12595 {
12596 /* Expand the pack expansion type. */
12599 in_decl);
12605 else
12606 {
12607 /* We're substituting into a member template, so
12608 we got a TYPE_PACK_EXPANSION back. Add that
12609 expansion and move on. */
12613 expanded_specs,
12614 complain);
12617 }
12618 }
12621 {
12624 else
12629 complain);
12630 }
12633 }
12634 }
12636 }
12638 /* Take the tree structure T and replace template parameters used
12639 therein with the argument vector ARGS. IN_DECL is an associated
12640 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12641 Issue error and warning messages under control of COMPLAIN. Note
12642 that we must be relatively non-tolerant of extensions here, in
12643 order to preserve conformance; if we allow substitutions that
12644 should not be allowed, we may allow argument deductions that should
12645 not succeed, and therefore report ambiguous overload situations
12646 where there are none. In theory, we could allow the substitution,
12647 but indicate that it should have failed, and allow our caller to
12648 make sure that the right thing happens, but we don't try to do this
12649 yet.
12651 This function is used for dealing with types, decls and the like;
12652 for expressions, use tsubst_expr or tsubst_copy. */
12654 tree
12656 {
12679 else
12684 /* Reuse typedefs. We need to do this to handle dependent attributes,
12685 such as attribute aligned. */
12688 {
12692 {
12693 /* DECL represents an alias template and we want to
12694 instantiate it. */
12698 }
12702 {
12706 }
12711 else
12712 /* The typedef is from a non-template context. */
12716 {
12718 r = cp_build_qualified_type_real
12722 }
12723 else
12724 {
12725 /* We don't have an instantiation yet, so drop the typedef. */
12730 }
12731 }
12744 {
12770 {
12776 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
12777 needed. */
12783 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
12784 with TREE_SIDE_EFFECTS that indicates this is not an integral
12785 constant expression. */
12788 {
12791 }
12794 }
12800 {
12806 /* Early in template argument deduction substitution, we don't
12807 want to reduce the level of 'auto', or it will be confused
12808 with a normal template parm in subsequent deduction. */
12820 {
12824 {
12825 /* See through ARGUMENT_PACK_SELECT arguments. */
12827 /* If the selected argument is an expansion E, that most
12828 likely means we were called from
12829 gen_elem_of_pack_expansion_instantiation during the
12830 substituting of pack an argument pack (which Ith
12831 element is a pack expansion, where I is
12832 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
12833 In this case, the Ith element resulting from this
12834 substituting is going to be a pack expansion, which
12835 pattern is the pattern of E. Let's return the
12836 pattern of E, and
12837 gen_elem_of_pack_expansion_instantiation will
12838 build the resulting pack expansion from it. */
12840 {
12841 /* Make sure we aren't throwing away arg info. */
12844 }
12845 }
12846 }
12851 {
12853 /* If ARG is an argument pack, we don't actually want to
12854 perform a substitution here, because substitutions
12855 for argument packs are only done
12856 element-by-element. We can get to this point when
12857 substituting the type of a non-type template
12858 parameter pack, when that type actually contains
12859 template parameter packs from an outer template, e.g.,
12861 template<typename... Types> struct A {
12862 template<Types... Values> struct B { };
12863 }; */
12867 {
12873 return cp_build_qualified_type_real
12875 }
12877 {
12878 /* We are processing a type constructed from a
12879 template template parameter. */
12890 /* Consider this code:
12892 template <template <class> class Template>
12893 struct Internal {
12894 template <class Arg> using Bind = Template<Arg>;
12895 };
12897 template <template <class> class Template, class Arg>
12898 using Instantiate = Template<Arg>; //#0
12900 template <template <class> class Template,
12901 class Argument>
12902 using Bind =
12903 Instantiate<Internal<Template>::template Bind,
12904 Argument>; //#1
12906 When #1 is parsed, the
12907 BOUND_TEMPLATE_TEMPLATE_PARM representing the
12908 parameter `Template' in #0 matches the
12909 UNBOUND_CLASS_TEMPLATE representing the argument
12910 `Internal<Template>::template Bind'; We then want
12911 to assemble the type `Bind<Argument>' that can't
12912 be fully created right now, because
12913 `Internal<Template>' not being complete, the Bind
12914 template cannot be looked up in that context. So
12915 we need to "store" `Bind<Argument>' for later
12916 when the context of Bind becomes complete. Let's
12917 store that in a TYPENAME_TYPE. */
12921 argvec),
12922 typename_type,
12923 complain);
12925 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
12926 are resolving nested-types in the signature of a
12927 member function templates. Otherwise ARG is a
12928 TEMPLATE_DECL and is the real template to be
12929 instantiated. */
12937 complain);
12938 return cp_build_qualified_type_real
12940 }
12941 else
12942 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
12944 }
12947 /* This can happen during the attempted tsubst'ing in
12948 unify. This means that we don't yet have any information
12949 about the template parameter in question. */
12952 /* If we get here, we must have been looking at a parm for a
12953 more deeply nested template. Make a new version of this
12954 template parameter, but with a lower level. */
12956 {
12961 {
12963 r = cp_build_qualified_type_real
12967 }
12974 /* Break infinite recursion when substituting the constraints
12976 else
12977 {
12987 /* Propagate constraints on placeholders. */
12994 /* We have reduced the level of the template
12995 template parameter, but not the levels of its
12996 template parameters, so canonical_type_parameter
12997 will not be able to find the canonical template
12998 template parameter for this level. Thus, we
12999 require structural equality checking to compare
13000 TEMPLATE_TEMPLATE_PARMs. */
13004 else
13008 {
13016 }
13017 }
13026 }
13029 }
13032 {
13040 {
13044 }
13047 {
13051 }
13054 {
13058 }
13064 }
13067 /* We should never be tsubsting a binfo. */
13071 /* A vector of template arguments. */
13077 {
13081 /* [temp.deduct]
13083 Type deduction may fail for any of the following
13084 reasons:
13086 -- Attempting to create a pointer to reference type.
13087 -- Attempting to create a reference to a reference type or
13088 a reference to void.
13090 Core issue 106 says that creating a reference to a reference
13091 during instantiation is no longer a cause for failure. We
13092 only enforce this check in strict C++98 mode. */
13096 {
13099 /* We keep track of the last time we issued this error
13100 message to avoid spewing a ton of messages during a
13101 single bad template instantiation. */
13104 {
13109 else
13112 }
13115 }
13119 {
13121 {
13124 type);
13125 else
13127 type);
13128 }
13130 }
13132 {
13136 }
13138 /* In C++0x, during template argument substitution, when there is an
13139 attempt to create a reference to a reference type, reference
13140 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13142 "If a template-argument for a template-parameter T names a type
13143 that is a reference to a type A, an attempt to create the type
13144 'lvalue reference to cv T' creates the type 'lvalue reference to
13145 A,' while an attempt to create the type type rvalue reference to
13146 cv T' creates the type T"
13147 */
13148 r = cp_build_reference_type
13151 else
13156 /* Will this ever be needed for TYPE_..._TO values? */
13160 }
13162 {
13165 {
13166 /* [temp.deduct]
13168 Type deduction may fail for any of the following
13169 reasons:
13171 -- Attempting to create "pointer to member of T" when T
13172 is not a class type. */
13176 }
13178 {
13182 }
13184 {
13188 }
13191 {
13192 /* The type of the implicit object parameter gets its
13193 cv-qualifiers from the FUNCTION_TYPE. */
13194 tree memptr;
13195 tree method_type
13200 complain);
13201 }
13202 else
13205 complain);
13206 }
13209 {
13210 tree fntype;
13211 tree specs;
13216 /* Substitute the exception specification. */
13224 }
13226 {
13231 /* As an optimization, we avoid regenerating the array type if
13232 it will obviously be the same as T. */
13236 /* These checks should match the ones in create_array_type_for_decl.
13238 [temp.deduct]
13240 The deduction may fail for any of the following reasons:
13242 -- Attempting to create an array with an element type that
13243 is void, a function type, or a reference type, or [DR337]
13244 an abstract class type. */
13250 {
13254 }
13262 {
13265 }
13268 }
13271 {
13281 {
13285 }
13287 {
13288 /* Normally, make_typename_type does not require that the CTX
13289 have complete type in order to allow things like:
13291 template <class T> struct S { typename S<T>::X Y; };
13293 But, such constructs have already been resolved by this
13294 point, so here CTX really should have complete type, unless
13295 it's a partial instantiation. */
13298 {
13302 }
13303 }
13310 {
13313 }
13316 {
13318 {
13322 else
13324 }
13326 {
13330 else
13332 }
13333 }
13335 return cp_build_qualified_type_real
13337 }
13340 {
13352 }
13355 {
13356 tree type;
13372 complain);
13373 }
13376 {
13377 tree type;
13395 else
13396 {
13400 /* In a template ~id could be either a complement expression
13401 or an unqualified-id naming a destructor; if instantiating
13402 it produces an expression, it's not an id-expression or
13403 member access. */
13406 }
13411 }
13414 {
13418 }
13422 {
13424 tree packed_out =
13426 args,
13427 complain,
13428 in_decl);
13431 /* For template nontype argument packs, also substitute into
13432 the type. */
13437 }
13453 /* We should use one of the expression tsubsts for these codes. */
13459 }
13460 }
13462 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13463 type of the expression on the left-hand side of the "." or "->"
13464 operator. */
13466 static tree
13469 {
13470 tree name;
13471 tree qualifying_scope;
13472 tree fns;
13473 tree optype;
13478 /* A baselink indicates a function from a base class. Both the
13479 BASELINK_ACCESS_BINFO and the base class referenced may
13480 indicate bases of the template class, rather than the
13481 instantiated class. In addition, lookups that were not
13482 ambiguous before may be ambiguous now. Therefore, we perform
13483 the lookup again. */
13490 {
13497 }
13505 /* If lookup found a single function, mark it as used at this
13506 point. (If it lookup found multiple functions the one selected
13507 later by overload resolution will be marked as used at that
13508 point.) */
13515 /* Add back the template arguments, if present. */
13520 template_args);
13521 /* Update the conversion operator type. */
13529 qualifying_scope,
13530 object_type);
13532 }
13534 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13535 true if the qualified-id will be a postfix-expression in-and-of
13536 itself; false if more of the postfix-expression follows the
13537 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13538 of "&". */
13540 static tree
13544 {
13545 tree expr;
13546 tree scope;
13547 tree name;
13549 tree template_args;
13554 /* Figure out what name to look up. */
13557 {
13565 }
13566 else
13567 {
13570 }
13572 /* Substitute into the qualifying scope. When there are no ARGS, we
13573 are just trying to simplify a non-dependent expression. In that
13574 case the qualifying scope may be dependent, and, in any case,
13575 substituting will not help. */
13578 {
13581 }
13582 else
13586 {
13591 }
13594 {
13596 {
13597 /* A BIT_NOT_EXPR is used to represent a destructor. */
13599 {
13603 }
13604 else
13607 }
13608 else
13612 {
13614 {
13618 }
13620 }
13621 }
13624 {
13626 scope);
13627 /* Remember that there was a reference to this entity. */
13630 }
13633 {
13639 }
13648 {
13649 expr = (adjust_result_of_qualified_name_lookup
13651 expr = (finish_qualified_id_expr
13655 }
13657 /* Expressions do not generally have reference type. */
13659 /* However, if we're about to form a pointer-to-member, we just
13660 want the referenced member referenced. */
13665 }
13667 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
13668 initializer, DECL is the substituted VAR_DECL. Other arguments are as
13669 for tsubst. */
13671 static tree
13674 {
13681 {
13682 /* If we had an initializer but it
13683 instantiated to nothing,
13684 value-initialize the object. This will
13685 only occur when the initializer was a
13686 pack expansion where the parameter packs
13687 used in that expansion were of length
13688 zero. */
13690 complain);
13693 }
13696 }
13698 /* Like tsubst, but deals with expressions. This function just replaces
13699 template parms; to finish processing the resultant expression, use
13700 tsubst_copy_and_build or tsubst_expr. */
13702 static tree
13704 {
13706 tree r;
13714 {
13719 {
13720 /* We get here for a use of 'this' in an NSDMI. */
13722 && current_function_decl
13726 /* This can happen for a parameter name used later in a function
13727 declaration (such as in a late-specified return type). Just
13728 make a dummy decl, since it's only used for its type. */
13731 /* Give it the template pattern as its context; its true context
13732 hasn't been instantiated yet and this is good enough for
13733 mangling. */
13735 }
13744 {
13745 tree enum_type;
13746 tree v;
13750 /* There is no need to substitute into namespace-scope
13751 enumerators. */
13754 /* If ARGS is NULL, then T is known to be non-dependent. */
13758 /* Unfortunately, we cannot just call lookup_name here.
13759 Consider:
13761 template <int I> int f() {
13762 enum E { a = I };
13763 struct S { void g() { E e = a; } };
13764 };
13766 When we instantiate f<7>::S::g(), say, lookup_name is not
13767 clever enough to find f<7>::a. */
13768 enum_type
13778 /* We didn't find the name. That should never happen; if
13779 name-lookup found it during preliminary parsing, we
13780 should find it again here during instantiation. */
13782 }
13787 {
13788 /* Check for a local specialization set up by
13789 tsubst_pack_expansion. */
13791 {
13795 }
13797 /* When retrieving a capture pack from a generic lambda, remove the
13798 lambda call op's own template argument list from ARGS. Only the
13799 template arguments active for the closure type should be used to
13800 retrieve the pack specialization. */
13806 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
13807 tsubst_decl put in the hash table. */
13809 }
13812 {
13813 tree ctx;
13818 {
13821 {
13825 }
13827 }
13828 }
13837 {
13840 {
13841 /* First try name lookup to find the instantiation. */
13844 {
13845 /* Make sure that the one we found is the one we want. */
13851 }
13855 else
13856 {
13857 /* This can happen for a variable used in a
13858 late-specified return type of a local lambda, or for a
13859 local static or constant. Building a new VAR_DECL
13860 should be OK in all those cases. */
13863 {
13864 /* We can't call cp_finish_decl, so handle the
13865 initializer by hand. */
13876 }
13881 {
13884 at_eof);
13885 else
13887 }
13888 }
13889 /* Remember this for subsequent uses. */
13892 }
13893 }
13894 else
13904 /* An OVERLOAD will always be a non-dependent overload set; an
13905 overload set from function scope will just be represented with an
13906 IDENTIFIER_NODE, and from class scope with a BASELINK. */
13922 {
13923 /* Template template argument like the following example need
13924 special treatment:
13926 template <template <class> class TT> struct C {};
13927 template <class T> struct D {
13928 template <class U> struct E {};
13929 C<E> c; // #1
13930 };
13931 D<int> d; // #2
13933 We are processing the template argument `E' in #1 for
13934 the template instantiation #2. Originally, `E' is a
13935 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
13936 have to substitute this with one having context `D<int>'. */
13940 }
13941 else
13942 /* Ordinary template template argument. */
13953 {
13957 }
13961 {
13970 /* We only want to compute the number of arguments. */
13984 {
13987 else
13993 else
13996 }
13997 else
13999 }
14001 {
14009 }
14010 /* Fall through */
14026 {
14030 }
14033 {
14034 tree object;
14035 tree name;
14040 {
14044 }
14047 {
14057 }
14062 in_decl);
14063 else
14066 }
14104 {
14108 }
14111 {
14116 }
14119 {
14123 }
14126 {
14134 }
14140 {
14147 }
14150 {
14157 }
14160 {
14167 }
14170 {
14171 /* Substituted template arguments */
14180 }
14183 {
14203 }
14228 /* Fall through. */
14231 {
14234 }
14235 else
14239 /* This is handled by tsubst_copy_and_build. */
14243 {
14247 }
14250 /* We shouldn't have built any of these during initial template
14251 generation. Instead, they should be built during instantiation
14252 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14256 {
14266 }
14284 {
14285 /* Instantiate any typedefs in the type. */
14290 }
14293 /* These can sometimes show up in a partial instantiation, but never
14294 involve template parms. */
14308 /* We shouldn't get here, but keep going if !flag_checking. */
14312 }
14313 }
14315 /* Helper function for tsubst_omp_clauses, used for instantiation of
14316 OMP_CLAUSE_DECL of clauses. */
14318 static tree
14320 tree in_decl)
14321 {
14325 /* Handle an OpenMP array section represented as a TREE_LIST (or
14326 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
14327 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
14328 TREE_LIST. We can handle it exactly the same as an array section
14329 (purpose, value, and a chain), even though the nomenclature
14330 (low_bound, length, etc) is different. */
14332 {
14333 tree low_bound
14339 in_decl);
14348 }
14351 /* Undo convert_from_reference tsubst_expr could have called. */
14357 }
14359 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14361 static tree
14364 {
14369 {
14375 {
14378 {
14384 }
14385 /* FALLTHRU */
14401 in_decl);
14432 {
14435 {
14442 }
14443 else
14445 }
14448 in_decl);
14454 in_decl);
14462 in_decl);
14464 {
14467 }
14472 else
14475 in_decl,
14498 {
14502 loc;
14504 {
14507 }
14508 }
14512 }
14515 {
14526 /* tsubst_expr on SCOPE_REF results in returning
14527 finish_non_static_data_member result. Undo that here. */
14531 {
14536 {
14540 CASE_CONVERT:
14549 /* FALLTHRU */
14553 }
14554 }
14560 {
14563 {
14567 }
14568 }
14572 }
14573 }
14577 {
14582 {
14585 }
14586 }
14588 }
14590 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
14592 static tree
14594 tree in_decl)
14595 {
14596 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
14616 {
14619 else
14620 {
14624 }
14625 }
14630 #undef RECUR
14631 }
14633 /* Used to temporarily communicate the list of #pragma omp parallel
14634 clauses to #pragma omp for instantiation if they are combined
14635 together. */
14639 /* Substitute one OMP_FOR iterator. */
14641 static void
14646 {
14647 #define RECUR(NODE) \
14648 tsubst_expr ((NODE), args, complain, in_decl, \
14649 integral_constant_expression_p)
14656 {
14659 }
14665 {
14666 /* We need to jump through some hoops to handle declarations in the
14667 for-init-statement, since we might need to handle auto deduction,
14668 but we need to keep control of initialization. */
14672 }
14673 else
14674 {
14676 {
14679 {
14683 {
14687 CASE_CONVERT:
14695 {
14698 }
14699 /* FALLTHRU */
14703 }
14704 }
14705 }
14706 else
14708 }
14719 {
14721 {
14722 /* Declare the variable, but don't let that initialize it. */
14727 }
14732 {
14737 }
14738 else
14745 }
14748 {
14749 /* Declare and initialize the variable. */
14752 }
14754 {
14758 {
14760 {
14766 {
14769 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
14774 }
14777 {
14779 decl);
14781 }
14784 {
14786 decl);
14788 }
14789 else
14791 }
14794 }
14796 {
14801 {
14804 }
14805 }
14806 }
14809 {
14813 }
14814 else
14818 {
14829 {
14837 }
14838 else
14844 {
14850 }
14854 {
14862 }
14863 else
14869 }
14875 #undef RECUR
14876 }
14878 /* Helper function of tsubst_expr, find OMP_TEAMS inside
14879 of OMP_TARGET's body. */
14881 static tree
14883 {
14886 {
14895 }
14897 }
14899 /* Like tsubst_copy for expressions, etc. but also does semantic
14900 processing. */
14902 tree
14905 {
14906 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14907 #define RECUR(NODE) \
14908 tsubst_expr ((NODE), args, complain, in_decl, \
14909 integral_constant_expression_p)
14912 tree r;
14913 location_t loc;
14925 {
14927 {
14928 tree_stmt_iterator i;
14932 }
14947 else
14956 {
14958 tree init;
14964 {
14967 tree decl;
14975 else
14977 }
14979 {
14980 /* Don't build up decls for a variadic capture proxy, we'll
14981 instantiate the elements directly as needed. */
14983 }
14984 else
14985 {
14989 {
14990 /* By marking the declaration as instantiated, we avoid
14991 trying to instantiate it. Since instantiate_decl can't
14992 handle local variables, and since we've already done
14993 all that needs to be done, that's the right thing to
14994 do. */
14999 /* Anonymous aggregates are a special case. */
15002 {
15005 {
15009 }
15011 }
15017 {
15022 }
15023 else
15024 {
15029 {
15030 /* For __PRETTY_FUNCTION__ we have to adjust the
15031 initializer. */
15035 }
15036 else
15040 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15043 }
15044 }
15045 }
15048 }
15063 {
15073 }
15100 {
15104 }
15112 else
15120 else
15141 {
15145 }
15149 {
15151 tree label;
15156 }
15162 /* Computed goto's must be tsubst'd into. On the other hand,
15163 non-computed gotos must not be; the identifier in question
15164 will have no binding. */
15166 else
15172 {
15188 }
15193 {
15198 }
15199 else
15200 {
15205 else
15212 else
15218 else
15220 }
15224 {
15228 {
15230 /* Prevent instantiate_decl from trying to instantiate
15231 this variable. We've already done all that needs to be
15232 done. */
15235 }
15240 }
15246 {
15247 /* Local classes are not independent templates; they are
15248 instantiated along with their containing function. And this
15249 way we don't have to deal with pushing out of one local class
15250 to instantiate a member of another local class. */
15251 tree fn;
15252 /* Closures are handled by the LAMBDA_EXPR. */
15258 }
15262 {
15263 tree condition;
15266 condition =
15268 args,
15277 }
15283 in_decl);
15320 {
15332 {
15339 }
15351 integral_constant_expression_p);
15362 else
15363 {
15371 }
15375 }
15380 /* FALLTHRU */
15415 {
15418 {
15419 /* For combined target teams, ensure the num_teams and
15420 thread_limit clause expressions are evaluated on the host,
15421 before entering the target construct. */
15422 tree c;
15428 {
15437 OMP_CLAUSE_FIRSTPRIVATE);
15441 }
15442 }
15443 }
15503 {
15508 {
15511 }
15517 }
15518 else
15519 {
15526 {
15529 }
15532 {
15537 {
15540 }
15546 }
15547 else
15548 {
15552 }
15555 }
15559 {
15565 {
15569 {
15574 }
15578 }
15579 else
15580 {
15585 }
15586 }
15590 {
15594 }
15614 /* If the first operand was a statement, we're done with it. */
15618 complain));
15630 integral_constant_expression_p));
15631 }
15634 out:
15637 #undef RECUR
15638 #undef RETURN
15639 }
15641 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
15642 function. For description of the body see comment above
15643 cp_parser_omp_declare_reduction_exprs. */
15645 static void
15647 {
15653 tree_stmt_iterator tsi;
15664 {
15683 }
15685 {
15705 }
15706 }
15708 /* T is a postfix-expression that is not being used in a function
15709 call. Return the substituted version of T. */
15711 static tree
15713 tsubst_flags_t complain,
15714 tree in_decl)
15715 {
15719 else
15725 }
15727 /* Like tsubst but deals with expressions and performs semantic
15728 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
15730 tree
15732 tree args,
15733 tsubst_flags_t complain,
15734 tree in_decl,
15737 {
15738 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
15739 #define RECUR(NODE) \
15740 tsubst_copy_and_build (NODE, args, complain, in_decl, \
15742 integral_constant_expression_p)
15745 location_t loc;
15754 /* N3276 decltype magic only applies to calls at the top level or on the
15755 right side of a comma. */
15760 {
15763 /* Fall through. */
15765 {
15766 tree decl;
15767 cp_id_kind idk;
15772 {
15775 }
15777 /* Look up the name. */
15780 /* By convention, expressions use ERROR_MARK_NODE to indicate
15781 failure, not NULL_TREE. */
15787 integral_constant_expression_p,
15795 input_location);
15799 {
15803 }
15805 }
15808 {
15809 tree object;
15819 {
15822 {
15825 }
15827 }
15830 {
15833 }
15834 else
15841 else
15843 }
15846 {
15850 {
15851 /* A type conversion to reference type will be enclosed in
15852 such an indirect ref, but the substitution of the cast
15853 will have also added such an indirect ref. */
15856 }
15857 else
15861 }
15864 {
15868 }
15871 {
15878 flags));
15879 }
15882 {
15886 }
15893 {
15894 tree type;
15900 {
15905 }
15911 {
15929 }
15932 }
15966 else
15968 in_decl);
16003 {
16010 tree r = build_x_binary_op
16012 op0,
16014 ? ERROR_MARK
16016 op1,
16018 ? ERROR_MARK
16026 }
16029 {
16033 }
16046 {
16055 }
16059 /* Fall through */
16062 {
16063 tree r;
16069 {
16070 /* When there are no ARGS, we are trying to evaluate a
16071 non-dependent expression from the parser. Trying to do
16072 the substitutions may not work. */
16075 }
16076 else
16077 {
16082 else
16085 /*integral_constant_expression_p=*/
16089 }
16093 else
16097 {
16099 {
16101 {
16105 }
16106 else
16110 }
16112 }
16114 }
16117 {
16127 }
16143 {
16147 tree r = build_x_modify_expr
16150 /* TREE_NO_WARNING must be set if either the expression was
16151 parenthesized or it uses an operator such as >>= rather
16152 than plain assignment. In the former case, it was already
16153 set and must be copied. In the latter case,
16154 build_x_modify_expr sets it and it must not be reset
16155 here. */
16160 }
16165 /* Remember that there was a reference to this entity. */
16172 {
16177 tree ret;
16181 else
16182 {
16186 }
16188 /* If there was an initializer in the original tree, but it
16189 instantiated to an empty list, then we should pass a
16190 non-NULL empty vector to tell build_new that it was an
16191 empty initializer() rather than no initializer. This can
16192 only happen when the initializer is a pack expansion whose
16193 parameter packs are of length zero. */
16196 else
16197 {
16201 else
16202 {
16205 }
16206 }
16212 complain);
16220 }
16223 {
16229 complain));
16230 }
16233 {
16237 integral_constant_expression_p);
16239 op0,
16242 }
16245 {
16246 tree function;
16251 tree ret;
16254 /* When we parsed the expression, we determined whether or
16255 not Koenig lookup should be performed. */
16258 {
16263 }
16265 {
16266 /* Do nothing; calling tsubst_copy_and_build on an identifier
16267 would incorrectly perform unqualified lookup again.
16269 Note that we can also have an IDENTIFIER_NODE if the earlier
16270 unqualified lookup found a member function; in that case
16271 koenig_p will be false and we do want to do the lookup
16272 again to find the instantiated member function.
16274 FIXME but doing that causes c++/15272, so we need to stop
16275 using IDENTIFIER_NODE in that situation. */
16277 }
16278 else
16279 {
16281 {
16287 }
16288 else
16293 /* Avoid error about taking the address of a constructor. */
16297 in_decl,
16299 integral_constant_expression_p);
16303 }
16308 {
16313 else
16314 {
16315 /* Expand the pack expansion and push each entry onto
16316 CALL_ARGS. */
16319 {
16324 {
16329 }
16330 }
16331 else
16332 {
16333 /* A partial substitution. Add one entry. */
16335 }
16336 }
16337 }
16339 /* We do not perform argument-dependent lookup if normal
16340 lookup finds a non-function, in accordance with the
16341 expected resolution of DR 218. */
16344 /* If lookup found a member function, the Koenig lookup is
16345 not appropriate, even if an unqualified-name was used
16346 to denote the function. */
16349 /* Only do this when substitution turns a dependent call
16350 into a non-dependent call. */
16357 {
16359 {
16360 /* For backwards compatibility and good diagnostics, try
16361 the unqualified lookup again if we aren't in SFINAE
16362 context. */
16363 tree unq = (tsubst_copy_and_build
16365 integral_constant_expression_p));
16370 {
16379 "%qD was not declared in this scope, "
16380 "and no declarations were found by "
16381 "argument-dependent lookup at the point "
16383 {
16387 {
16389 input_location);
16391 "declarations in dependent base %qT are "
16397 else
16401 }
16402 else
16404 "%qD declared here, later in the "
16406 }
16408 }
16409 }
16411 {
16416 }
16417 }
16419 /* Remember that there was a reference to this entity. */
16424 /* Put back tf_decltype for the actual call. */
16429 complain);
16431 {
16446 complain);
16447 else
16448 ret = (build_new_method_call
16453 complain));
16454 }
16455 else
16458 koenig_p,
16459 complain);
16464 }
16467 {
16473 {
16475 {
16480 }
16481 else
16482 {
16487 }
16489 }
16490 else
16491 {
16494 }
16498 }
16501 {
16506 input_location));
16507 }
16510 {
16518 {
16519 /* We have pack expansions, so expand those and
16520 create a new list out of it. */
16523 tree chain;
16526 /* Expand the argument expressions. */
16534 /* Build the rest of the list. */
16539 /* Determine the number of arguments. */
16541 {
16544 }
16547 else
16548 {
16549 /* Since we only performed a partial substitution into
16550 the argument pack, we only RETURN (a single list
16551 node. */
16558 }
16560 /* Convert the argument vectors into a TREE_LIST */
16563 {
16564 /* Grab the Ith values. */
16565 i--;
16568 value
16572 /* Build the list (backwards). */
16574 }
16577 }
16593 }
16596 {
16597 tree object;
16598 tree object_type;
16599 tree member;
16600 tree r;
16604 /* Remember that there was a reference to this entity. */
16615 else
16623 {
16625 {
16630 {
16633 }
16635 {
16640 }
16641 }
16642 }
16645 {
16646 /* Lookup the template functions now that we know what the
16647 scope is. */
16655 {
16658 args);
16659 member = (adjust_result_of_qualified_name_lookup
16661 object_type));
16662 }
16663 else
16664 {
16666 input_location);
16668 }
16669 }
16673 {
16675 {
16679 else
16682 }
16684 }
16686 {
16691 }
16695 complain);
16699 }
16706 {
16714 tree r;
16719 /* digest_init will do the wrong thing if we let it. */
16723 /* We do not want to process the index of aggregate
16724 initializers as they are identifier nodes which will be
16725 looked up by digest_init. */
16731 {
16733 /* An identifier index is looked up in the type
16734 being initialized, not the current scope. */
16739 {
16740 /* Substitute into the pack expansion. */
16742 in_decl);
16746 ;
16748 /* Just move the argument into place. */
16750 else
16751 {
16752 /* Update the length of the final CONSTRUCTOR
16753 arguments vector, and note that we will need to
16754 copy.*/
16757 }
16758 }
16759 else
16761 }
16764 {
16769 {
16771 {
16776 }
16777 else
16779 }
16780 }
16790 }
16793 {
16796 {
16799 }
16800 else
16801 {
16804 }
16805 }
16811 {
16812 /* We don't build decls for an instantiation of a
16813 variadic capture proxy, we instantiate the elements
16814 when needed. */
16817 }
16818 /* Fall through */
16821 {
16823 /* ??? We're doing a subset of finish_id_expression here. */
16825 && !processing_template_decl
16826 && !cp_unevaluated_operand
16829 {
16831 /* Replace an evaluated use of the thread_local variable with
16832 a call to its wrapper. */
16834 }
16836 {
16840 }
16843 /* If the original type was a reference, we'll be wrapped in
16844 the appropriate INDIRECT_REF. */
16847 }
16850 {
16854 }
16861 {
16872 }
16875 {
16881 integral_constant_expression_p);
16885 /* If the resulting list of expression statement is empty,
16886 fold it further into void_node. */
16891 }
16894 {
16912 /* For a function or variable scope, we want to use tsubst so that we
16913 don't complain about referring to an auto before deduction. */
16916 {
16917 /* Look up the parameter we want directly, as tsubst_copy
16918 doesn't do what we need. */
16924 /* FIXME Work around the parm not having DECL_CONTEXT set. */
16927 }
16929 /* For a field, use tsubst_copy so that we look up the existing field
16930 rather than build a new one. */
16932 else
16941 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16943 /* Now that we know visibility, instantiate the type so we have a
16944 declaration of the op() for later calls to lambda_function. */
16952 }
16955 /* We can get here for a constant initializer of non-dependent type.
16956 FIXME stop folding in cp_parser_initializer_clause. */
16957 {
16959 complain);
16961 }
16965 integral_constant_expression_p));
16971 {
16976 complain));
16977 }
16983 /* Handle Objective-C++ constructs, if appropriate. */
16984 {
16985 tree subst
16990 }
16992 }
16994 #undef RECUR
16995 #undef RETURN
16996 out:
16999 }
17001 /* Verify that the instantiated ARGS are valid. For type arguments,
17002 make sure that the type's linkage is ok. For non-type arguments,
17003 make sure they are constants if they are integral or enumerations.
17004 Emit an error under control of COMPLAIN, and return TRUE on error. */
17006 static bool
17008 {
17012 {
17022 }
17024 {
17025 /* [basic.link]: A name with no linkage (notably, the name
17026 of a class or enumeration declared in a local scope)
17027 shall not be used to declare an entity with linkage.
17028 This implies that names with no linkage cannot be used as
17029 template arguments
17031 DR 757 relaxes this restriction for C++0x. */
17036 {
17037 /* DR 488 makes use of a type with no linkage cause
17038 type deduction to fail. */
17040 {
17043 else
17046 }
17048 }
17049 /* In order to avoid all sorts of complications, we do not
17050 allow variably-modified types as template arguments. */
17052 {
17056 }
17057 }
17058 /* Class template and alias template arguments should be OK. */
17060 ;
17061 /* A non-type argument of integral or enumerated type must be a
17062 constant. */
17067 {
17071 }
17073 }
17075 static bool
17077 {
17082 {
17085 }
17089 }
17091 /* We're out of SFINAE context now, so generate diagnostics for the access
17092 errors we saw earlier when instantiating D from TMPL and ARGS. */
17094 static void
17096 {
17108 }
17110 /* Instantiate the indicated variable, function, or alias template TMPL with
17111 the template arguments in TARG_PTR. */
17113 static tree
17115 {
17117 tree fndecl;
17118 tree gen_tmpl;
17119 tree spec;
17127 /* If this function is a clone, handle it specially. */
17129 {
17130 tree spec;
17131 tree clone;
17133 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
17134 DECL_CLONED_FUNCTION. */
17140 /* Look for the clone. */
17144 /* We should always have found the clone by now. */
17147 }
17152 /* Check to see if we already have this specialization. */
17155 /* The TMPL is a partial instantiation. To get a full set of
17156 arguments we must add the arguments used to perform the
17157 partial instantiation. */
17159 targ_ptr);
17161 /* It would be nice to avoid hashing here and then again in tsubst_decl,
17162 but it doesn't seem to be on the hot path. */
17171 {
17173 {
17177 }
17179 }
17182 complain))
17185 /* We are building a FUNCTION_DECL, during which the access of its
17186 parameters and return types have to be checked. However this
17187 FUNCTION_DECL which is the desired context for access checking
17188 is not built yet. We solve this chicken-and-egg problem by
17189 deferring all checks until we have the FUNCTION_DECL. */
17192 /* Instantiation of the function happens in the context of the function
17193 template, not the context of the overload resolution we're doing. */
17195 /* If there are dependent arguments, e.g. because we're doing partial
17196 ordering, make sure processing_template_decl stays set. */
17200 {
17204 }
17209 {
17210 /* We need to determine if we're using a partial or explicit
17211 specialization now, because the type of the variable could be
17212 different. */
17218 {
17222 }
17223 }
17225 /* Substitute template parameters to obtain the specialization. */
17232 {
17235 }
17237 /* The DECL_TI_TEMPLATE should always be the immediate parent
17238 template, not the most general template. */
17242 /* Now we know the specialization, compute access previously
17243 deferred. */
17250 /* If we've just instantiated the main entry point for a function,
17251 instantiate all the alternate entry points as well. We do this
17252 by cloning the instantiation of the main entry point, not by
17253 instantiating the template clones. */
17258 {
17260 {
17261 /* Remember to reinstantiate when we're out of SFINAE so the user
17262 can see the errors. */
17264 }
17266 }
17268 }
17270 /* Wrapper for instantiate_template_1. */
17272 tree
17274 {
17275 tree ret;
17280 }
17282 /* Instantiate the alias template TMPL with ARGS. Also push a template
17283 instantiation level, which instantiate_template doesn't do because
17284 functions and variables have sufficient context established by the
17285 callers. */
17287 static tree
17289 {
17296 {
17299 }
17301 args =
17309 /* We can't free this if a pending_template entry or last_error_tinst_level
17310 is pointing at it. */
17316 }
17318 /* PARM is a template parameter pack for FN. Returns true iff
17319 PARM is used in a deducible way in the argument list of FN. */
17321 static bool
17323 {
17326 {
17328 tree packs;
17334 {
17335 /* The template parameter pack is used in a function parameter
17336 pack. If this is the end of the parameter list, the
17337 template parameter pack is deducible. */
17340 else
17341 /* Otherwise, not. Well, it could be deduced from
17342 a non-pack parameter, but doing so would end up with
17343 a deduction mismatch, so don't bother. */
17345 }
17346 }
17347 /* The template parameter pack isn't used in any function parameter
17348 packs, but it might be used deeper, e.g. tuple<Args...>. */
17350 }
17352 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
17353 NARGS elements of the arguments that are being used when calling
17354 it. TARGS is a vector into which the deduced template arguments
17355 are placed.
17357 Returns either a FUNCTION_DECL for the matching specialization of FN or
17358 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
17359 true, diagnostics will be printed to explain why it failed.
17361 If FN is a conversion operator, or we are trying to produce a specific
17362 specialization, RETURN_TYPE is the return type desired.
17364 The EXPLICIT_TARGS are explicit template arguments provided via a
17365 template-id.
17367 The parameter STRICT is one of:
17369 DEDUCE_CALL:
17370 We are deducing arguments for a function call, as in
17371 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
17372 deducing arguments for a call to the result of a conversion
17373 function template, as in [over.call.object].
17375 DEDUCE_CONV:
17376 We are deducing arguments for a conversion function, as in
17377 [temp.deduct.conv].
17379 DEDUCE_EXACT:
17380 We are deducing arguments when doing an explicit instantiation
17381 as in [temp.explicit], when determining an explicit specialization
17382 as in [temp.expl.spec], or when taking the address of a function
17383 template, as in [temp.deduct.funcaddr]. */
17385 tree
17387 tree explicit_targs,
17388 tree targs,
17391 tree return_type,
17392 unification_kind_t strict,
17396 {
17397 tree parms;
17398 tree fntype;
17406 tree tinst;
17412 /* In C++0x, it's possible to have a function template whose type depends
17413 on itself recursively. This is most obvious with decltype, but can also
17414 occur with enumeration scope (c++/48969). So we need to catch infinite
17415 recursion and reject the substitution at deduction time; this function
17416 will return error_mark_node for any repeated substitution.
17418 This also catches excessive recursion such as when f<N> depends on
17419 f<N-1> across all integers, and returns error_mark_node for all the
17420 substitutions back up to the initial one.
17422 This is, of course, not reentrant. */
17432 {
17433 /* [temp.deduct]
17435 The specified template arguments must match the template
17436 parameters in kind (i.e., type, nontype, template), and there
17437 must not be more arguments than there are parameters;
17438 otherwise type deduction fails.
17440 Nontype arguments must match the types of the corresponding
17441 nontype template parameters, or must be convertible to the
17442 types of the corresponding nontype parameters as specified in
17443 _temp.arg.nontype_, otherwise type deduction fails.
17445 All references in the function type of the function template
17446 to the corresponding template parameters are replaced by the
17447 specified template argument values. If a substitution in a
17448 template parameter or in the function type of the function
17449 template results in an invalid type, type deduction fails. */
17454 /* Adjust any explicit template arguments before entering the
17455 substitution context. */
17456 explicit_targs
17458 complain,
17464 /* Substitute the explicit args into the function type. This is
17465 necessary so that, for instance, explicitly declared function
17466 arguments can match null pointed constants. If we were given
17467 an incomplete set of explicit args, we must not do semantic
17468 processing during substitution as we could create partial
17469 instantiations. */
17471 {
17476 /* Dig out the actual parm. */
17479 {
17482 }
17484 {
17487 }
17490 /* No explicit argument for this template parameter. */
17494 {
17495 /* Mark the argument pack as "incomplete". We could
17496 still deduce more arguments during unification.
17497 We remove this mark in type_unification_real. */
17499 {
17503 }
17505 /* We have some incomplete argument packs. */
17507 }
17508 }
17512 {
17515 }
17518 /* Ignore any access checks; we'll see them again in
17519 instantiate_template and they might have the wrong
17520 access path at this point. */
17532 /* Place the explicitly specified arguments in TARGS. */
17535 }
17537 /* Never do unification on the 'this' parameter. */
17541 {
17542 /* We're deducing for a call to the result of a template conversion
17543 function. The parms we really want are in return_type. */
17547 }
17549 {
17558 }
17560 /* We allow incomplete unification without an error message here
17561 because the standard doesn't seem to explicitly prohibit it. Our
17562 callers must be ready to deal with unification failures in any
17563 event. */
17566 /* If we aren't explaining yet, push tinst context so we can see where
17567 any errors (e.g. from class instantiations triggered by instantiation
17568 of default template arguments) come from. If we are explaining, this
17569 context is redundant. */
17571 {
17574 }
17576 /* type_unification_real will pass back any access checks from default
17577 template argument substitution. */
17589 /* Now that we have bindings for all of the template arguments,
17590 ensure that the arguments deduced for the template template
17591 parameters have compatible template parameter lists. We cannot
17592 check this property before we have deduced all template
17593 arguments, because the template parameter types of a template
17594 template parameter might depend on prior template parameters
17595 deduced after the template template parameter. The following
17596 ill-formed example illustrates this issue:
17598 template<typename T, template<T> class C> void f(C<5>, T);
17600 template<int N> struct X {};
17602 void g() {
17603 f(X<5>(), 5l); // error: template argument deduction fails
17604 }
17606 The template parameter list of 'C' depends on the template type
17607 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
17608 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
17609 time that we deduce 'C'. */
17612 {
17615 }
17617 /* All is well so far. Now, check:
17619 [temp.deduct]
17621 When all template arguments have been deduced, all uses of
17622 template parameters in nondeduced contexts are replaced with
17623 the corresponding deduced argument values. If the
17624 substitution results in an invalid type, as described above,
17625 type deduction fails. */
17628 {
17631 }
17633 /* Also collect access checks from the instantiation. */
17646 /* Now perform any access checks encountered during substitution. */
17653 /* If we're looking for an exact match, check that what we got
17654 is indeed an exact match. It might not be if some template
17655 parameters are used in non-deduced contexts. But don't check
17656 for an exact match if we have dependent template arguments;
17657 in that case we're doing partial ordering, and we already know
17658 that we have two candidates that will provide the actual type. */
17660 {
17664 tree sarg
17670 {
17674 }
17675 }
17679 fail:
17682 {
17684 /* Reset once we're all the way out. */
17686 }
17688 /* We can't free this if a pending_template entry or last_error_tinst_level
17689 is pointing at it. */
17695 }
17697 /* Adjust types before performing type deduction, as described in
17698 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
17699 sections are symmetric. PARM is the type of a function parameter
17700 or the return type of the conversion function. ARG is the type of
17701 the argument passed to the call, or the type of the value
17702 initialized with the result of the conversion function.
17703 ARG_EXPR is the original argument expression, which may be null. */
17705 static int
17709 tree arg_expr)
17710 {
17714 {
17719 /* Swap PARM and ARG throughout the remainder of this
17720 function; the handling is precisely symmetric since PARM
17721 will initialize ARG rather than vice versa. */
17726 /* Core issue #873: Do the DR606 thing (see below) for these cases,
17727 too, but here handle it by stripping the reference from PARM
17728 rather than by adding it to ARG. */
17736 /* Nothing else to do in this case. */
17741 }
17744 {
17745 /* [temp.deduct.call]
17747 If P is not a reference type:
17749 --If A is an array type, the pointer type produced by the
17750 array-to-pointer standard conversion (_conv.array_) is
17751 used in place of A for type deduction; otherwise,
17753 --If A is a function type, the pointer type produced by
17754 the function-to-pointer standard conversion
17755 (_conv.func_) is used in place of A for type deduction;
17756 otherwise,
17758 --If A is a cv-qualified type, the top level
17759 cv-qualifiers of A's type are ignored for type
17760 deduction. */
17765 else
17767 }
17769 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
17770 of the form T&&, where T is a template parameter, and the argument
17771 is an lvalue, T is deduced as A& */
17777 /* try_one_overload doesn't provide an arg_expr, but
17778 functions are always lvalues. */
17782 /* [temp.deduct.call]
17784 If P is a cv-qualified type, the top level cv-qualifiers
17785 of P's type are ignored for type deduction. If P is a
17786 reference type, the type referred to by P is used for
17787 type deduction. */
17790 {
17793 }
17795 /* DR 322. For conversion deduction, remove a reference type on parm
17796 too (which has been swapped into ARG). */
17801 }
17803 /* Subroutine of unify_one_argument. PARM is a function parameter of a
17804 template which does contain any deducible template parameters; check if
17805 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
17806 unify_one_argument. */
17808 static int
17811 {
17812 tree type;
17816 else
17823 {
17827 }
17829 {
17834 }
17838 else
17840 }
17844 /* Returns true iff the expression EXPR is one from which a template
17845 argument can be deduced. In other words, if it's an undecorated
17846 use of a template non-type parameter. */
17848 static bool
17850 {
17852 }
17854 /* Returns true iff the array domain DOMAIN uses a template parameter in a
17855 deducible way; that is, if it has a max value of <PARM> - 1. */
17857 static bool
17859 {
17868 }
17870 /* Returns true iff the template arguments ARGS use a template parameter
17871 in a deducible way. */
17873 static bool
17875 {
17877 {
17882 else
17883 {
17890 else
17892 }
17895 }
17897 }
17899 /* Returns true iff TYPE contains any deducible references to template
17900 parameters, as per 14.8.2.5. */
17902 static bool
17904 {
17908 /* T
17909 cv-list T
17910 TT<T>
17911 TT<i>
17912 TT<> */
17917 /* T*
17918 T&
17919 T&& */
17923 /* T[integer-constant ]
17924 type [i] */
17929 /* T type ::*
17930 type T::*
17931 T T::*
17932 T (type ::*)()
17933 type (T::*)()
17934 type (type ::*)(T)
17935 type (T::*)(T)
17936 T (type ::*)(T)
17937 T (T::*)()
17938 T (T::*)(T) */
17941 || (uses_deducible_template_parms
17944 /* template-name <T> (where template-name refers to a class template)
17945 template-name <i> (where template-name refers to a class template) */
17952 /* type (T)
17953 T()
17954 T(T) */
17957 {
17966 }
17969 }
17971 /* Subroutine of type_unification_real and unify_pack_expansion to
17972 handle unification of a single P/A pair. Parameters are as
17973 for those functions. */
17975 static int
17979 {
17986 /* We can't deduce anything from this, but we might get all the
17987 template args from other function args. */
17990 /* Implicit conversions (Clause 4) will be performed on a function
17991 argument to convert it to the type of the corresponding function
17992 parameter if the parameter type contains no template-parameters that
17993 participate in template argument deduction. */
17996 /* For function parameters with no deducible template parameters,
17997 just return. We'll check non-dependent conversions later. */
18001 {
18003 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18004 | UNIFY_ALLOW_MORE_CV_QUAL
18018 }
18020 /* We only do these transformations if this is the top-level
18021 parameter_type_list in a call or declaration matching; in other
18022 situations (nested function declarators, template argument lists) we
18023 won't be comparing a type to an expression, and we don't do any type
18024 adjustments. */
18026 {
18028 {
18031 {
18032 /* [temp.deduct.type] A template-argument can be
18033 deduced from a pointer to function or pointer
18034 to member function argument if the set of
18035 overloaded functions does not contain function
18036 templates and at most one of a set of
18037 overloaded functions provides a unique
18038 match. */
18045 }
18051 }
18053 arg_strict |=
18055 }
18056 else
18061 /* For deduction from an init-list we need the actual list. */
18065 }
18067 /* Most parms like fn_type_unification.
18069 If SUBR is 1, we're being called recursively (to unify the
18070 arguments of a function or method parameter of a function
18071 template).
18073 CHECKS is a pointer to a vector of access checks encountered while
18074 substituting default template arguments. */
18076 static int
18078 tree targs,
18079 tree xparms,
18083 unification_kind_t strict,
18087 {
18092 tree parms;
18101 /* Reset the number of non-defaulted template arguments contained
18102 in TARGS. */
18105 again:
18113 {
18118 /* For a function parameter pack that occurs at the end of the
18119 parameter-declaration-list, the type A of each remaining
18120 argument of the call is compared with the type P of the
18121 declarator-id of the function parameter pack. */
18127 /* For a function parameter pack that does not occur at the
18128 end of the parameter-declaration-list, the type of the
18129 parameter pack is a non-deduced context. */
18136 explain_p))
18138 }
18143 {
18144 /* Unify the remaining arguments with the pack expansion type. */
18145 tree argvec;
18148 /* Allocate a TREE_VEC and copy in all of the arguments */
18153 /* Copy the parameter into parmvec. */
18159 /* Advance to the end of the list of parameters. */
18161 }
18163 /* Fail if we've reached the end of the parm list, and more args
18164 are present, and the parm list isn't variadic. */
18167 /* Fail if parms are left and they don't have default values and
18168 they aren't all deduced as empty packs (c++/57397). This is
18169 consistent with sufficient_parms_p. */
18172 {
18176 do
18177 {
18180 count++;
18182 }
18186 type_pack_p);
18187 }
18190 {
18191 tsubst_flags_t complain = (explain_p
18192 ? tf_warning_or_error
18196 {
18200 /* Clear the "incomplete" flags on all argument packs now so that
18201 substituting them into later default arguments works. */
18203 {
18206 }
18212 /* If this is an undeduced nontype parameter that depends on
18213 a type parameter, try another pass; its type may have been
18214 deduced from a later argument than the one from which
18215 this parameter can be deduced. */
18219 {
18222 }
18224 /* Core issue #226 (C++0x) [temp.deduct]:
18226 If a template argument has not been deduced, its
18227 default template argument, if any, is used.
18229 When we are in C++98 mode, TREE_PURPOSE will either
18230 be NULL_TREE or ERROR_MARK_NODE, so we do not need
18231 to explicitly check cxx_dialect here. */
18233 /* OK, there is a default argument. Wait until after the
18234 conversion check to do substitution. */
18237 /* If the type parameter is a parameter pack, then it will
18238 be deduced to an empty parameter pack. */
18240 {
18241 tree arg;
18244 {
18248 }
18249 else
18256 }
18259 }
18261 /* DR 1391: All parameters have args, now check non-dependent parms for
18262 convertibility. */
18266 {
18272 /* For a function parameter pack that occurs at the end of the
18273 parameter-declaration-list, the type A of each remaining
18274 argument of the call is compared with the type P of the
18275 declarator-id of the function parameter pack. */
18281 /* For a function parameter pack that does not occur at the
18282 end of the parameter-declaration-list, the type of the
18283 parameter pack is a non-deduced context. */
18292 explain_p))
18294 }
18296 /* Now substitute into the default template arguments. */
18298 {
18324 else
18325 {
18327 /* The position of the first default template argument,
18328 is also the number of non-defaulted arguments in TARGS.
18329 Record that. */
18333 }
18334 }
18338 }
18344 }
18346 /* Subroutine of type_unification_real. Args are like the variables
18347 at the call site. ARG is an overloaded function (or template-id);
18348 we try deducing template args from each of the overloads, and if
18349 only one succeeds, we go with that. Modifies TARGS and returns
18350 true on success. */
18352 static bool
18354 tree targs,
18355 tree parm,
18356 tree arg,
18357 unification_kind_t strict,
18360 {
18367 {
18370 }
18371 else
18375 /* Handle `&x' where `x' is some static or non-static member
18376 function name. */
18382 /* Strip baselink information. */
18387 {
18388 /* If we got some explicit template args, we need to plug them into
18389 the affected templates before we try to unify, in case the
18390 explicit args will completely resolve the templates in question. */
18397 {
18410 {
18415 {
18418 }
18419 }
18422 }
18423 /* If no templates (or more than one) are fully resolved by the
18424 explicit arguments, this template-id is a non-deduced context; it
18425 could still be OK if we deduce all template arguments for the
18426 enclosing call through other arguments. */
18429 }
18432 /* If ARG is, for example, "(0, &f)" then its type will be unknown
18433 -- but the deduction does not succeed because the expression is
18434 not just the function on its own. */
18436 else
18442 {
18445 }
18447 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18448 to function or pointer to member function argument if the set of
18449 overloaded functions does not contain function templates and at most
18450 one of a set of overloaded functions provides a unique match.
18452 So if we found multiple possibilities, we return success but don't
18453 deduce anything. */
18456 {
18460 {
18465 /* Don't forget explicit template arguments in a pack. */
18469 }
18470 }
18475 }
18477 /* Core DR 115: In contexts where deduction is done and fails, or in
18478 contexts where deduction is not done, if a template argument list is
18479 specified and it, along with any default template arguments, identifies
18480 a single function template specialization, then the template-id is an
18481 lvalue for the function template specialization. */
18483 tree
18485 {
18498 {
18501 }
18503 {
18506 }
18508 {
18511 }
18514 {
18518 /* If we got some explicit template args, we need to plug them into
18519 the affected templates before we try to unify, in case the
18520 explicit args will completely resolve the templates in question. */
18528 {
18541 {
18544 {
18547 }
18549 {
18552 }
18553 }
18554 }
18556 {
18564 {
18565 tree base
18568 }
18572 }
18574 /* There were no good options and at least one bad one, so let the
18575 user know what the problem is. */
18577 }
18579 }
18581 /* Subroutine of resolve_overloaded_unification; does deduction for a single
18582 overload. Fills TARGS with any deduced arguments, or error_mark_node if
18583 different overloads deduce different arguments for a given parm.
18584 ADDR_P is true if the expression for which deduction is being
18585 performed was of the form "& fn" rather than simply "fn".
18587 Returns 1 on success. */
18589 static int
18591 tree orig_targs,
18592 tree targs,
18593 tree parm,
18594 tree arg,
18595 unification_kind_t strict,
18599 {
18601 tree tempargs;
18607 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18608 to function or pointer to member function argument if the set of
18609 overloaded functions does not contain function templates and at most
18610 one of a set of overloaded functions provides a unique match.
18612 So if this is a template, just return success. */
18624 /* We don't copy orig_targs for this because if we have already deduced
18625 some template args from previous args, unify would complain when we
18626 try to deduce a template parameter for the same argument, even though
18627 there isn't really a conflict. */
18634 /* First make sure we didn't deduce anything that conflicts with
18635 explicitly specified args. */
18637 {
18644 /* Since we're unifying against ourselves, we will fill in
18645 template args used in the function parm list with our own
18646 template parms. Discard them. */
18650 }
18653 {
18658 }
18661 }
18663 /* PARM is a template class (perhaps with unbound template
18664 parameters). ARG is a fully instantiated type. If ARG can be
18665 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
18666 TARGS are as for unify. */
18668 static tree
18671 {
18672 tree copy_of_targs;
18679 /* We need to make a new template argument vector for the call to
18680 unify. If we used TARGS, we'd clutter it up with the result of
18681 the attempted unification, even if this class didn't work out.
18682 We also don't want to commit ourselves to all the unifications
18683 we've already done, since unification is supposed to be done on
18684 an argument-by-argument basis. In other words, consider the
18685 following pathological case:
18687 template <int I, int J, int K>
18688 struct S {};
18690 template <int I, int J>
18691 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
18693 template <int I, int J, int K>
18694 void f(S<I, J, K>, S<I, I, I>);
18696 void g() {
18697 S<0, 0, 0> s0;
18698 S<0, 1, 2> s2;
18700 f(s0, s2);
18701 }
18703 Now, by the time we consider the unification involving `s2', we
18704 already know that we must have `f<0, 0, 0>'. But, even though
18705 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
18706 because there are two ways to unify base classes of S<0, 1, 2>
18707 with S<I, I, I>. If we kept the already deduced knowledge, we
18708 would reject the possibility I=1. */
18711 /* If unification failed, we're done. */
18717 }
18719 /* Given a template type PARM and a class type ARG, find the unique
18720 base type in ARG that is an instance of PARM. We do not examine
18721 ARG itself; only its base-classes. If there is not exactly one
18722 appropriate base class, return NULL_TREE. PARM may be the type of
18723 a partial specialization, as well as a plain template type. Used
18724 by unify. */
18726 static enum template_base_result
18729 {
18731 tree binfo;
18737 {
18738 /* The type could not be completed. */
18741 }
18743 /* Walk in inheritance graph order. The search order is not
18744 important, and this avoids multiple walks of virtual bases. */
18746 {
18751 {
18752 /* If there is more than one satisfactory baseclass, then:
18754 [temp.deduct.call]
18756 If they yield more than one possible deduced A, the type
18757 deduction fails.
18759 applies. */
18761 {
18764 }
18767 }
18768 }
18772 }
18774 /* Returns the level of DECL, which declares a template parameter. */
18776 static int
18778 {
18780 {
18790 }
18792 }
18794 /* Decide whether ARG can be unified with PARM, considering only the
18795 cv-qualifiers of each type, given STRICT as documented for unify.
18796 Returns nonzero iff the unification is OK on that basis. */
18798 static int
18800 {
18806 {
18807 /* Although a CVR qualifier is ignored when being applied to a
18808 substituted template parameter ([8.3.2]/1 for example), that
18809 does not allow us to unify "const T" with "int&" because both
18810 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
18811 It is ok when we're allowing additional CV qualifiers
18812 at the outer level [14.8.2.1]/3,1st bullet. */
18822 }
18833 }
18835 /* Determines the LEVEL and INDEX for the template parameter PARM. */
18836 void
18838 {
18842 {
18845 }
18846 else
18847 {
18850 }
18851 }
18853 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
18854 do { \
18855 if (unify (TP, TA, P, A, S, EP)) \
18856 return 1; \
18857 } while (0);
18859 /* Unifies the remaining arguments in PACKED_ARGS with the pack
18860 expansion at the end of PACKED_PARMS. Returns 0 if the type
18861 deduction succeeds, 1 otherwise. STRICT is the same as in
18862 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
18863 call argument list. We'll need to adjust the arguments to make them
18864 types. SUBR tells us if this is from a recursive call to
18865 type_unification_real, or for comparing two template argument
18866 lists. */
18868 static int
18872 {
18873 tree parm
18883 /* Determine the parameter packs we will be deducing from the
18884 pattern, and record their current deductions. */
18887 {
18891 /* Determine the index and level of this parameter pack. */
18894 /* Keep track of the parameter packs and their corresponding
18895 argument packs. */
18898 }
18900 /* Loop through all of the arguments that have not yet been
18901 unified and unify each with the pattern. */
18903 {
18904 tree parm;
18908 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
18909 or the element of its argument pack at the current index if
18910 this argument was explicitly specified. */
18912 {
18921 {
18924 }
18926 }
18928 /* If we had explicit template arguments, substitute them into the
18929 pattern before deduction. */
18931 {
18932 /* Some arguments might still be unspecified or dependent. */
18940 NULL_TREE);
18945 }
18946 else
18949 /* Unify the pattern with the current argument. */
18951 explain_p))
18954 /* For each parameter pack, collect the deduced value. */
18956 {
18962 }
18963 }
18965 /* Verify that the results of unification with the parameter packs
18966 produce results consistent with what we've seen before, and make
18967 the deduced argument packs available. */
18969 {
18976 /* By default keep the original deduced argument pack.
18977 If necessary, more specific code is going to update the
18978 resulting deduced argument later down in this function. */
18982 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
18983 actually deduce anything. */
18991 {
18992 /* If we had fewer function args than explicit template args,
18993 just use the explicits. */
18998 }
19001 {
19002 tree result;
19003 /* Build the deduced *_ARGUMENT_PACK. */
19005 {
19010 }
19011 else
19016 /* Note the deduced argument packs for this parameter
19017 pack. */
19019 }
19023 {
19024 /* We only had the explicitly-provided arguments before, but
19025 now we have a complete set of arguments. */
19031 }
19032 else
19033 {
19039 /* Inconsistent unification of this parameter pack. */
19041 bad_old_arg,
19042 bad_new_arg);
19043 }
19044 }
19047 }
19049 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
19050 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
19051 parameters and return value are as for unify. */
19053 static int
19057 {
19058 tree parm_max;
19059 tree arg_max;
19063 /* Our representation of array types uses "N - 1" as the
19064 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
19065 not an integer constant. We cannot unify arbitrarily
19066 complex expressions, so we eliminate the MINUS_EXPRs
19067 here. */
19071 {
19074 }
19078 {
19079 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
19080 trying to unify the type of a variable with the type
19081 of a template parameter. For example:
19083 template <unsigned int N>
19084 void f (char (&) [N]);
19085 int g();
19086 void h(int i) {
19087 char a[g(i)];
19088 f(a);
19089 }
19091 Here, the type of the ARG will be "int [g(i)]", and
19092 may be a SAVE_EXPR, etc. */
19096 }
19098 /* If only one of the bounds used a MINUS_EXPR, compensate
19099 by adding one to the other bound. */
19102 integer_type_node,
19103 parm_max,
19104 integer_one_node);
19107 integer_type_node,
19108 arg_max,
19109 integer_one_node);
19113 }
19115 /* Deduce the value of template parameters. TPARMS is the (innermost)
19116 set of template parameters to a template. TARGS is the bindings
19117 for those template parameters, as determined thus far; TARGS may
19118 include template arguments for outer levels of template parameters
19119 as well. PARM is a parameter to a template function, or a
19120 subcomponent of that parameter; ARG is the corresponding argument.
19121 This function attempts to match PARM with ARG in a manner
19122 consistent with the existing assignments in TARGS. If more values
19123 are deduced, then TARGS is updated.
19125 Returns 0 if the type deduction succeeds, 1 otherwise. The
19126 parameter STRICT is a bitwise or of the following flags:
19128 UNIFY_ALLOW_NONE:
19129 Require an exact match between PARM and ARG.
19130 UNIFY_ALLOW_MORE_CV_QUAL:
19131 Allow the deduced ARG to be more cv-qualified (by qualification
19132 conversion) than ARG.
19133 UNIFY_ALLOW_LESS_CV_QUAL:
19134 Allow the deduced ARG to be less cv-qualified than ARG.
19135 UNIFY_ALLOW_DERIVED:
19136 Allow the deduced ARG to be a template base class of ARG,
19137 or a pointer to a template base class of the type pointed to by
19138 ARG.
19139 UNIFY_ALLOW_INTEGER:
19140 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
19141 case for more information.
19142 UNIFY_ALLOW_OUTER_LEVEL:
19143 This is the outermost level of a deduction. Used to determine validity
19144 of qualification conversions. A valid qualification conversion must
19145 have const qualified pointers leading up to the inner type which
19146 requires additional CV quals, except at the outer level, where const
19147 is not required [conv.qual]. It would be normal to set this flag in
19148 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
19149 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
19150 This is the outermost level of a deduction, and PARM can be more CV
19151 qualified at this point.
19152 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
19153 This is the outermost level of a deduction, and PARM can be less CV
19154 qualified at this point. */
19156 static int
19159 {
19161 tree targ;
19162 tree tparm;
19165 /* I don't think this will do the right thing with respect to types.
19166 But the only case I've seen it in so far has been array bounds, where
19167 signedness is the only information lost, and I think that will be
19168 okay. */
19176 /* We can't deduce anything from this, but we might get all the
19177 template args from other function args. */
19180 /* If PARM uses template parameters, then we can't bail out here,
19181 even if ARG == PARM, since we won't record unifications for the
19182 template parameters. We might need them if we're trying to
19183 figure out which of two things is more specialized. */
19187 /* Handle init lists early, so the rest of the function can assume
19188 we're dealing with a type. */
19190 {
19195 /* Replace T with std::initializer_list<T> for deduction. */
19202 /* We can only deduce from an initializer list argument if the
19203 parameter is std::initializer_list or an array; otherwise this
19204 is a non-deduced context. */
19209 else
19210 {
19212 /* Deduction is defined in terms of a single type, so just punt
19213 on the (bizarre) std::initializer_list<T...>. */
19216 }
19219 {
19226 {
19230 /* It should only be possible to get here for a call. */
19232 elt_strict |= maybe_adjust_types_for_deduction
19235 }
19238 explain_p);
19239 }
19243 {
19244 /* Also deduce from the length of the initializer list. */
19251 }
19253 /* If the std::initializer_list<T> deduction worked, replace the
19254 deduced A with std::initializer_list<A>. */
19256 {
19261 }
19263 }
19265 /* Immediately reject some pairs that won't unify because of
19266 cv-qualification mismatches. */
19269 /* It is the elements of the array which hold the cv quals of an array
19270 type, and the elements might be template type parms. We'll check
19271 when we recurse. */
19273 /* We check the cv-qualifiers when unifying with template type
19274 parameters below. We want to allow ARG `const T' to unify with
19275 PARM `T' for example, when computing which of two templates
19276 is more specialized, for example. */
19290 {
19294 /* In a type which contains a nested-name-specifier, template
19295 argument values cannot be deduced for template parameters used
19296 within the nested-name-specifier. */
19308 /* The PARM is not one we're trying to unify. Just check
19309 to see if it matches ARG. */
19310 {
19315 else
19317 }
19324 /* Check for mixed types and values. */
19332 {
19333 /* ARG must be constructed from a template class or a template
19334 template parameter. */
19338 {
19340 /* An alias template name is never deduced. */
19345 tree parm_parms
19346 = DECL_INNERMOST_TEMPLATE_PARMS
19351 /* The resolution to DR150 makes clear that default
19352 arguments for an N-argument may not be used to bind T
19353 to a template template parameter with fewer than N
19354 parameters. It is not safe to permit the binding of
19355 default arguments as an extension, as that may change
19356 the meaning of a conforming program. Consider:
19358 struct Dense { static const unsigned int dim = 1; };
19360 template <template <typename> class View,
19361 typename Block>
19362 void operator+(float, View<Block> const&);
19364 template <typename Block,
19365 unsigned int Dim = Block::dim>
19366 struct Lvalue_proxy { operator float() const; };
19368 void
19369 test_1d (void) {
19370 Lvalue_proxy<Dense> p;
19371 float b;
19372 b + p;
19373 }
19375 Here, if Lvalue_proxy is permitted to bind to View, then
19376 the global operator+ will be used; if they are not, the
19377 Lvalue_proxy will be converted to float. */
19379 full_argvec,
19381 (explain_p
19382 ? tf_warning_or_error
19389 /* Deduce arguments T, i from TT<T> or TT<i>.
19390 We check each element of PARMVEC and ARGVEC individually
19391 rather than the whole TREE_VEC since they can have
19392 different number of elements. */
19399 /* Check if the parameters end in a pack, making them
19400 variadic. */
19406 /* If the template argument list of P contains a pack
19407 expansion that is not the last template argument, the
19408 entire template argument list is a non-deduced
19409 context. */
19418 {
19423 }
19428 DEDUCE_EXACT,
19431 }
19434 /* Fall through to deduce template name. */
19435 }
19439 {
19440 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
19442 /* Simple cases: Value already set, does match or doesn't. */
19447 }
19448 else
19449 {
19450 /* If PARM is `const T' and ARG is only `int', we don't have
19451 a match unless we are allowing additional qualification.
19452 If ARG is `const int' and PARM is just `T' that's OK;
19453 that binds `const int' to `T'. */
19458 /* Consider the case where ARG is `const volatile int' and
19459 PARM is `const T'. Then, T should be `volatile int'. */
19460 arg = cp_build_qualified_type_real
19465 /* Simple cases: Value already set, does match or doesn't. */
19471 /* Make sure that ARG is not a variable-sized array. (Note
19472 that were talking about variable-sized arrays (like
19473 `int[n]'), rather than arrays of unknown size (like
19474 `int[]').) We'll get very confused by such a type since
19475 the bound of the array is not constant, and therefore
19476 not mangleable. Besides, such types are not allowed in
19477 ISO C++, so we can do as we please here. We do allow
19478 them for 'auto' deduction, since that isn't ABI-exposed. */
19482 /* Strip typedefs as in convert_template_argument. */
19484 }
19486 /* If ARG is a parameter pack or an expansion, we cannot unify
19487 against it unless PARM is also a parameter pack. */
19492 /* If the argument deduction results is a METHOD_TYPE,
19493 then there is a problem.
19494 METHOD_TYPE doesn't map to any real C++ type the result of
19495 the deduction can not be of that type. */
19509 {
19510 /* The PARM is not one we're trying to unify. Just check
19511 to see if it matches ARG. */
19517 }
19523 {
19528 }
19530 /* [temp.deduct.type] If, in the declaration of a function template
19531 with a non-type template-parameter, the non-type
19532 template-parameter is used in an expression in the function
19533 parameter-list and, if the corresponding template-argument is
19534 deduced, the template-argument type shall match the type of the
19535 template-parameter exactly, except that a template-argument
19536 deduced from an array bound may be of any integral type.
19537 The non-type parameter might use already deduced type parameters. */
19540 /* Template-parameter dependent expression. Just accept it for now.
19541 It will later be processed in convert_template_argument. */
19542 ;
19547 /* Convert the ARG to the type of PARM; the deduced non-type
19548 template argument must exactly match the types of the
19549 corresponding parameter. */
19552 /* We haven't deduced the type of this parameter yet. Try again
19553 later. */
19555 else
19558 /* If ARG is a parameter pack or an expansion, we cannot unify
19559 against it unless PARM is also a parameter pack. */
19564 {
19567 }
19572 {
19573 /* A pointer-to-member constant can be unified only with
19574 another constant. */
19578 /* Just unify the class member. It would be useless (and possibly
19579 wrong, depending on the strict flags) to unify also
19580 PTRMEM_CST_CLASS, because we want to be sure that both parm and
19581 arg refer to the same variable, even if through different
19582 classes. For instance:
19584 struct A { int x; };
19585 struct B : A { };
19587 Unification of &A::x and &B::x must succeed. */
19590 }
19593 {
19597 /* [temp.deduct.call]
19599 A can be another pointer or pointer to member type that can
19600 be converted to the deduced A via a qualification
19601 conversion (_conv.qual_).
19603 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
19604 This will allow for additional cv-qualification of the
19605 pointed-to types if appropriate. */
19608 /* The derived-to-base conversion only persists through one
19609 level of pointers. */
19614 }
19646 /* We have already checked cv-qualification at the top of the
19647 function. */
19651 /* As far as unification is concerned, this wins. Later checks
19652 will invalidate it if necessary. */
19655 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
19656 /* Type INTEGER_CST can come from ordinary constant template args. */
19668 {
19678 /* Check for pack expansions in the parameters. */
19680 {
19682 {
19684 /* We can unify against something with a trailing
19685 parameter pack. */
19687 else
19688 /* [temp.deduct.type]/9: If the template argument list of
19689 P contains a pack expansion that is not the last
19690 template argument, the entire template argument list
19691 is a non-deduced context. */
19693 }
19694 }
19696 /* If we don't have enough arguments to satisfy the parameters
19697 (not counting the pack expression at the end), or we have
19698 too many arguments for a parameter list that doesn't end in
19699 a pack expression, we can't unify. */
19705 /* Unify all of the parameters that precede the (optional)
19706 pack expression. */
19708 {
19713 }
19716 DEDUCE_EXACT,
19719 }
19727 {
19735 }
19740 {
19744 {
19745 /* First, we try to unify the PARM and ARG directly. */
19750 {
19751 /* Fallback to the special case allowed in
19752 [temp.deduct.call]:
19754 If P is a class, and P has the form
19755 template-id, then A can be a derived class of
19756 the deduced A. Likewise, if P is a pointer to
19757 a class of the form template-id, A can be a
19758 pointer to a derived class pointed to by the
19759 deduced A. */
19765 {
19766 /* Don't give the derived diagnostic if we're
19767 already dealing with the same template. */
19768 bool same_template
19774 }
19775 }
19776 }
19780 /* Perhaps PARM is something like S<U> and ARG is S<int>.
19781 Then, we should unify `int' and `U'. */
19783 else
19784 /* There's no chance of unification succeeding. */
19789 }
19796 {
19799 tree a;
19805 /* CV qualifications for methods can never be deduced, they must
19806 match exactly. We need to check them explicitly here,
19807 because type_unification_real treats them as any other
19808 cv-qualified parameter. */
19810 && (!check_cv_quals_for_unify
19830 }
19833 /* Unify a pointer to member with a pointer to member function, which
19834 deduces the type of the member as a function type. */
19836 {
19837 /* Check top-level cv qualifiers */
19845 /* Determine the type of the function we are unifying against. */
19849 }
19868 /* Matched cases are handled by the ARG == PARM test above. */
19872 /* A non-type template parameter that is a variable should be a
19873 an integral constant, in which case, it whould have been
19874 folded into its (constant) value. So we should not be getting
19875 a variable here. */
19886 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
19887 or UNDERLYING_TYPE nodes. */
19891 /* Unification fails if we hit an error node. */
19896 {
19901 }
19902 /* FALLTHRU */
19905 /* An unresolved overload is a nondeduced context. */
19910 /* We must be looking at an expression. This can happen with
19911 something like:
19913 template <int I>
19914 void foo(S<I>, S<I + 2>);
19916 This is a "nondeduced context":
19918 [deduct.type]
19920 The nondeduced contexts are:
19922 --A type that is a template-id in which one or more of
19923 the template-arguments is an expression that references
19924 a template-parameter.
19926 In these cases, we assume deduction succeeded, but don't
19927 actually infer any unifications. */
19932 else
19934 }
19935 }
19936 #undef RECUR_AND_CHECK_FAILURE
19937 \f
19938 /* Note that DECL can be defined in this translation unit, if
19939 required. */
19941 static void
19943 {
19944 tree clone;
19948 }
19950 /* Called if RESULT is explicitly instantiated, or is a member of an
19951 explicitly instantiated class. */
19953 void
19955 {
19958 /* If this entity has already been written out, it's too late to
19959 make any modifications. */
19963 /* For anonymous namespace we don't need to do anything. */
19965 {
19968 }
19971 /* The TREE_PUBLIC flag for function declarations will have been
19972 set correctly by tsubst. */
19975 /* This might have been set by an earlier implicit instantiation. */
19980 else
19981 {
19984 /* Always make artificials weak. */
19987 /* For WIN32 we also want to put explicit instantiations in
19988 linkonce sections. */
19991 }
19993 /* If EXTERN_P, then this function will not be emitted -- unless
19994 followed by an explicit instantiation, at which point its linkage
19995 will be adjusted. If !EXTERN_P, then this function will be
19996 emitted here. In neither circumstance do we want
19997 import_export_decl to adjust the linkage. */
19999 }
20001 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
20002 important template arguments. If any are missing, we check whether
20003 they're important by using error_mark_node for substituting into any
20004 args that were used for partial ordering (the ones between ARGS and END)
20005 and seeing if it bubbles up. */
20007 static bool
20009 {
20014 {
20017 }
20019 {
20023 }
20025 }
20027 /* Given two function templates PAT1 and PAT2, return:
20029 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
20030 -1 if PAT2 is more specialized than PAT1.
20031 0 if neither is more specialized.
20033 LEN indicates the number of parameters we should consider
20034 (defaulted parameters should not be considered).
20036 The 1998 std underspecified function template partial ordering, and
20037 DR214 addresses the issue. We take pairs of arguments, one from
20038 each of the templates, and deduce them against each other. One of
20039 the templates will be more specialized if all the *other*
20040 template's arguments deduce against its arguments and at least one
20041 of its arguments *does* *not* deduce against the other template's
20042 corresponding argument. Deduction is done as for class templates.
20043 The arguments used in deduction have reference and top level cv
20044 qualifiers removed. Iff both arguments were originally reference
20045 types *and* deduction succeeds in both directions, an lvalue reference
20046 wins against an rvalue reference and otherwise the template
20047 with the more cv-qualified argument wins for that pairing (if
20048 neither is more cv-qualified, they both are equal). Unlike regular
20049 deduction, after all the arguments have been deduced in this way,
20050 we do *not* verify the deduced template argument values can be
20051 substituted into non-deduced contexts.
20053 The logic can be a bit confusing here, because we look at deduce1 and
20054 targs1 to see if pat2 is at least as specialized, and vice versa; if we
20055 can find template arguments for pat1 to make arg1 look like arg2, that
20056 means that arg2 is at least as specialized as arg1. */
20058 int
20060 {
20073 /* Remove the this parameter from non-static member functions. If
20074 one is a non-static member function and the other is not a static
20075 member function, remove the first parameter from that function
20076 also. This situation occurs for operator functions where we
20077 locate both a member function (with this pointer) and non-member
20078 operator (with explicit first operand). */
20080 {
20085 }
20087 {
20090 {
20091 len--;
20093 }
20094 }
20096 /* If only one is a conversion operator, they are unordered. */
20100 /* Consider the return type for a conversion function */
20102 {
20105 len++;
20106 }
20108 processing_template_decl++;
20114 /* Stop when an ellipsis is seen. */
20116 {
20127 {
20128 /* When both arguments are pack expansions, we need only
20129 unify the patterns themselves. */
20133 /* This is the last comparison we need to do. */
20135 }
20138 {
20142 }
20145 {
20149 }
20155 {
20161 /* Setup the parameter vector, which contains only ARG1. */
20164 /* Setup the argument vector, which contains the remaining
20165 arguments. */
20174 /* We cannot deduce in the other direction, because ARG1 is
20175 a pack expansion but ARG2 is not. */
20177 }
20179 {
20185 /* Setup the parameter vector, which contains only ARG1. */
20188 /* Setup the argument vector, which contains the remaining
20189 arguments. */
20198 /* We cannot deduce in the other direction, because ARG2 is
20199 a pack expansion but ARG1 is not.*/
20201 }
20203 else
20204 {
20205 /* The normal case, where neither argument is a pack
20206 expansion. */
20213 }
20215 /* If we couldn't deduce arguments for tparms1 to make arg1 match
20216 arg2, then arg2 is not as specialized as arg1. */
20222 /* "If, for a given type, deduction succeeds in both directions
20223 (i.e., the types are identical after the transformations above)
20224 and both P and A were reference types (before being replaced with
20225 the type referred to above):
20226 - if the type from the argument template was an lvalue reference and
20227 the type from the parameter template was not, the argument type is
20228 considered to be more specialized than the other; otherwise,
20229 - if the type from the argument template is more cv-qualified
20230 than the type from the parameter template (as described above),
20231 the argument type is considered to be more specialized than the other;
20232 otherwise,
20233 - neither type is more specialized than the other." */
20236 {
20238 {
20241 else
20243 }
20245 {
20250 }
20251 }
20254 /* We've failed to deduce something in either direction.
20255 These must be unordered. */
20260 /* We have already processed all of the arguments in our
20261 handing of the pack expansion type. */
20266 }
20268 /* "In most cases, all template parameters must have values in order for
20269 deduction to succeed, but for partial ordering purposes a template
20270 parameter may remain without a value provided it is not used in the
20271 types being used for partial ordering."
20273 Thus, if we are missing any of the targs1 we need to substitute into
20274 origs1, then pat2 is not as specialized as pat1. This can happen when
20275 there is a nondeduced context. */
20281 processing_template_decl--;
20283 /* If both deductions succeed, the partial ordering selects the more
20284 constrained template. */
20286 {
20291 }
20293 /* All things being equal, if the next argument is a pack expansion
20294 for one function but not for the other, prefer the
20295 non-variadic function. FIXME this is bogus; see c++/41958. */
20299 {
20302 }
20308 else
20310 }
20312 /* Determine which of two partial specializations of TMPL is more
20313 specialized.
20315 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
20316 to the first partial specialization. The TREE_PURPOSE is the
20317 innermost set of template parameters for the partial
20318 specialization. PAT2 is similar, but for the second template.
20320 Return 1 if the first partial specialization is more specialized;
20321 -1 if the second is more specialized; 0 if neither is more
20322 specialized.
20324 See [temp.class.order] for information about determining which of
20325 two templates is more specialized. */
20327 static int
20329 {
20330 tree targs;
20341 /* Just like what happens for functions, if we are ordering between
20342 different template specializations, we may encounter dependent
20343 types in the arguments, and we need our dependency check functions
20344 to behave correctly. */
20348 {
20351 }
20355 {
20358 }
20361 /* If both deductions succeed, the partial ordering selects the more
20362 constrained template. */
20366 /* In the case of a tie where at least one of the templates
20367 has a parameter pack at the end, the template with the most
20368 non-packed parameters wins. */
20370 && any_deductions
20373 {
20379 /* We don't count the pack expansion at the end. */
20389 }
20392 }
20394 /* Return the template arguments that will produce the function signature
20395 DECL from the function template FN, with the explicit template
20396 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
20397 also match. Return NULL_TREE if no satisfactory arguments could be
20398 found. */
20400 static tree
20402 {
20406 tree decl_arg_types;
20409 tree arg;
20413 /* Never do unification on the 'this' parameter. */
20434 }
20436 /* Return the innermost template arguments that, when applied to a partial
20437 specialization of TMPL whose innermost template parameters are
20438 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
20439 ARGS.
20441 For example, suppose we have:
20443 template <class T, class U> struct S {};
20444 template <class T> struct S<T*, int> {};
20446 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
20447 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
20448 int}. The resulting vector will be {double}, indicating that `T'
20449 is bound to `double'. */
20451 static tree
20453 {
20455 tree deduced_args;
20456 tree innermost_deduced_args;
20460 {
20464 innermost_deduced_args);
20465 }
20466 else
20479 /* Verify that nondeduced template arguments agree with the type
20480 obtained from argument deduction.
20482 For example:
20484 struct A { typedef int X; };
20485 template <class T, class U> struct C {};
20486 template <class T> struct C<T, typename T::X> {};
20488 Then with the instantiation `C<A, int>', we can deduce that
20489 `T' is `A' but unify () does not check whether `typename T::X'
20490 is `int'. */
20496 /* We only need to check the innermost arguments; the other
20497 arguments will always agree. */
20502 /* Now that we have bindings for all of the template arguments,
20503 ensure that the arguments deduced for the template template
20504 parameters have compatible template parameter lists. See the use
20505 of template_template_parm_bindings_ok_p in fn_type_unification
20506 for more information. */
20511 }
20513 // Compare two function templates T1 and T2 by deducing bindings
20514 // from one against the other. If both deductions succeed, compare
20515 // constraints to see which is more constrained.
20516 static int
20518 {
20523 {
20526 }
20529 {
20532 }
20534 // If both deductions succeed, then one may be more constrained.
20539 }
20541 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
20542 Return the TREE_LIST node with the most specialized template, if
20543 any. If there is no most specialized template, the error_mark_node
20544 is returned.
20546 Note that this function does not look at, or modify, the
20547 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
20548 returned is one of the elements of INSTANTIATIONS, callers may
20549 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
20550 and retrieve it from the value returned. */
20552 tree
20554 {
20561 {
20566 {
20567 /* Equally specialized, move to next function. If there
20568 is no next function, nothing's most specialized. */
20573 }
20574 }
20577 /* Now verify that champ is better than everything earlier in the
20578 instantiation list. */
20581 {
20584 }
20585 }
20587 processing_template_decl--;
20593 }
20595 /* If DECL is a specialization of some template, return the most
20596 general such template. Otherwise, returns NULL_TREE.
20598 For example, given:
20600 template <class T> struct S { template <class U> void f(U); };
20602 if TMPL is `template <class U> void S<int>::f(U)' this will return
20603 the full template. This function will not trace past partial
20604 specializations, however. For example, given in addition:
20606 template <class T> struct S<T*> { template <class U> void f(U); };
20608 if TMPL is `template <class U> void S<int*>::f(U)' this will return
20609 `template <class T> template <class U> S<T*>::f(U)'. */
20611 tree
20613 {
20615 {
20618 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
20619 template friend, or a FIELD_DECL for a capture pack. */
20622 }
20624 /* Look for more and more general templates. */
20626 {
20627 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
20628 (See cp-tree.h for details.) */
20637 /* Stop if we run into an explicitly specialized class template. */
20644 }
20647 }
20649 /* Return the most specialized of the template partial specializations
20650 which can produce TARGET, a specialization of some class or variable
20651 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
20652 a TEMPLATE_DECL node corresponding to the partial specialization, while
20653 the TREE_PURPOSE is the set of template arguments that must be
20654 substituted into the template pattern in order to generate TARGET.
20656 If the choice of partial specialization is ambiguous, a diagnostic
20657 is issued, and the error_mark_node is returned. If there are no
20658 partial specializations matching TARGET, then NULL_TREE is
20659 returned, indicating that the primary template should be used. */
20661 static tree
20663 {
20665 tree t;
20666 tree champ;
20673 {
20677 }
20679 {
20682 }
20684 {
20688 }
20689 else
20694 /* For determining which partial specialization to use, only the
20695 innermost args are interesting. */
20697 {
20700 }
20703 {
20704 tree partial_spec_args;
20705 tree spec_args;
20713 {
20714 /* Discard the outer levels of args, and then substitute in the
20715 template args from the enclosing class. */
20717 partial_spec_args = tsubst_template_args
20720 /* And the same for the partial specialization TEMPLATE_DECL. */
20722 }
20724 partial_spec_args =
20726 partial_spec_args,
20740 partial_spec_args,
20741 args);
20743 {
20747 /* Keep the candidate only if the constraints are satisfied,
20748 or if we're not compiling with concepts. */
20751 {
20754 }
20755 }
20756 }
20766 {
20769 ;
20770 else
20771 {
20773 {
20776 {
20779 }
20780 }
20782 }
20783 }
20787 {
20790 {
20793 }
20794 }
20797 {
20804 else
20808 {
20813 }
20816 }
20819 }
20821 /* Explicitly instantiate DECL. */
20823 void
20825 {
20830 /* An error occurred, for which grokdeclarator has already issued
20831 an appropriate message. */
20834 {
20837 }
20843 {
20844 /* There is an asymmetry here in the way VAR_DECLs and
20845 FUNCTION_DECLs are handled by grokdeclarator. In the case of
20846 the latter, the DECL we get back will be marked as a
20847 template instantiation, and the appropriate
20848 DECL_TEMPLATE_INFO will be set up. This does not happen for
20849 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
20850 should handle VAR_DECLs as it currently handles
20851 FUNCTION_DECLs. */
20853 {
20856 }
20859 {
20862 }
20864 {
20869 }
20870 }
20872 {
20875 }
20876 else
20879 /* Check for various error cases. Note that if the explicit
20880 instantiation is valid the RESULT will currently be marked as an
20881 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
20882 until we get here. */
20885 {
20886 /* DR 259 [temp.spec].
20888 Both an explicit instantiation and a declaration of an explicit
20889 specialization shall not appear in a program unless the explicit
20890 instantiation follows a declaration of the explicit specialization.
20892 For a given set of template parameters, if an explicit
20893 instantiation of a template appears after a declaration of an
20894 explicit specialization for that template, the explicit
20895 instantiation has no effect. */
20897 }
20899 {
20900 /* [temp.spec]
20902 No program shall explicitly instantiate any template more
20903 than once.
20905 We check DECL_NOT_REALLY_EXTERN so as not to complain when
20906 the first instantiation was `extern' and the second is not,
20907 and EXTERN_P for the opposite case. */
20910 /* If an "extern" explicit instantiation follows an ordinary
20911 explicit instantiation, the template is instantiated. */
20914 }
20916 {
20919 }
20921 {
20924 }
20927 ;
20929 {
20932 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
20935 }
20936 else
20944 }
20946 static void
20948 {
20954 {
20957 }
20958 }
20960 /* Called from do_type_instantiation through binding_table_foreach to
20961 do recursive instantiation for the type bound in ENTRY. */
20962 static void
20964 {
20970 }
20972 /* Called from do_type_instantiation to instantiate a member
20973 (a member function or a static member variable) of an
20974 explicitly instantiated class template. */
20975 static void
20977 {
20982 }
20984 /* Perform an explicit instantiation of template class T. STORAGE, if
20985 non-null, is the RID for extern, inline or static. COMPLAIN is
20986 nonzero if this is called from the parser, zero if called recursively,
20987 since the standard is unclear (as detailed below). */
20989 void
20991 {
21001 {
21002 tree tmpl =
21006 else
21009 }
21014 {
21017 t);
21019 }
21022 {
21024 {
21026 {
21029 "ISO C++ 1998 forbids the use of %<extern%> on "
21031 }
21032 else
21034 "ISO C++ forbids the use of %qE"
21036 }
21044 else
21045 {
21047 storage);
21049 }
21050 }
21053 {
21054 /* DR 259 [temp.spec].
21056 Both an explicit instantiation and a declaration of an explicit
21057 specialization shall not appear in a program unless the explicit
21058 instantiation follows a declaration of the explicit specialization.
21060 For a given set of template parameters, if an explicit
21061 instantiation of a template appears after a declaration of an
21062 explicit specialization for that template, the explicit
21063 instantiation has no effect. */
21065 }
21067 {
21068 /* [temp.spec]
21070 No program shall explicitly instantiate any template more
21071 than once.
21073 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
21074 instantiation was `extern'. If EXTERN_P then the second is.
21075 These cases are OK. */
21082 /* If we've already instantiated the template, just return now. */
21085 }
21093 {
21094 tree tmp;
21096 /* In contrast to implicit instantiation, where only the
21097 declarations, and not the definitions, of members are
21098 instantiated, we have here:
21100 [temp.explicit]
21102 The explicit instantiation of a class template specialization
21103 implies the instantiation of all of its members not
21104 previously explicitly specialized in the translation unit
21105 containing the explicit instantiation.
21107 Of course, we can't instantiate member template classes, since
21108 we don't have any arguments for them. Note that the standard
21109 is unclear on whether the instantiation of the members are
21110 *explicit* instantiations or not. However, the most natural
21111 interpretation is that it should be an explicit instantiation. */
21126 }
21127 }
21129 /* Given a function DECL, which is a specialization of TMPL, modify
21130 DECL to be a re-instantiation of TMPL with the same template
21131 arguments. TMPL should be the template into which tsubst'ing
21132 should occur for DECL, not the most general template.
21134 One reason for doing this is a scenario like this:
21136 template <class T>
21137 void f(const T&, int i);
21139 void g() { f(3, 7); }
21141 template <class T>
21142 void f(const T& t, const int i) { }
21144 Note that when the template is first instantiated, with
21145 instantiate_template, the resulting DECL will have no name for the
21146 first parameter, and the wrong type for the second. So, when we go
21147 to instantiate the DECL, we regenerate it. */
21149 static void
21151 {
21152 /* The arguments used to instantiate DECL, from the most general
21153 template. */
21154 tree args;
21155 tree code_pattern;
21160 /* Make sure that we can see identifiers, and compute access
21161 correctly. */
21165 {
21166 tree decl_parm;
21167 tree pattern_parm;
21168 tree specs;
21182 specs);
21184 /* Merge parameter declarations. */
21187 pattern_parm
21191 {
21192 tree parm_type;
21193 tree attributes;
21198 NULL_TREE);
21204 {
21207 }
21210 }
21211 /* Merge any parameters that match with the function parameter
21212 pack. */
21214 {
21216 tree expanded_types;
21217 /* Expand the TYPE_PACK_EXPANSION that provides the types for
21218 the parameters in this function parameter pack. */
21223 {
21224 tree parm_type;
21225 tree attributes;
21228 /* Rename the parameter to include the index. */
21237 {
21240 }
21242 }
21243 }
21244 /* Merge additional specifiers from the CODE_PATTERN. */
21248 }
21250 {
21258 }
21259 else
21263 }
21265 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
21266 substituted to get DECL. */
21268 tree
21270 {
21273 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
21274 for the instantiation. This is not always the most general
21275 template. Consider, for example:
21277 template <class T>
21278 struct S { template <class U> void f();
21279 template <> void f<int>(); };
21281 and an instantiation of S<double>::f<int>. We want TD to be the
21282 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
21284 more general template. */
21286 /* We must also deal with friend templates. Given:
21288 template <class T> struct S {
21289 template <class U> friend void f() {};
21290 };
21292 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
21293 so far as the language is concerned, but that's still
21294 where we get the pattern for the instantiation from. On
21295 other hand, if the definition comes outside the class, say:
21297 template <class T> struct S {
21298 template <class U> friend void f();
21299 };
21300 template <class U> friend void f() {}
21302 we don't need to look any further. That's what the check for
21303 DECL_INITIAL is for. */
21307 {
21308 /* The present template, TD, should not be a definition. If it
21309 were a definition, we should be using it! Note that we
21310 cannot restructure the loop to just keep going until we find
21311 a template with a definition, since that might go too far if
21312 a specialization was declared, but not defined. */
21314 /* Fetch the more general template. */
21316 }
21319 }
21321 /* Returns true if we need to instantiate this template instance even if we
21322 know we aren't going to emit it. */
21324 bool
21326 {
21327 /* We always instantiate inline functions so that we can inline them. An
21328 explicit instantiation declaration prohibits implicit instantiation of
21329 non-inline functions. With high levels of optimization, we would
21330 normally inline non-inline functions -- but we're not allowed to do
21331 that for "extern template" functions. Therefore, we check
21332 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
21336 /* And we need to instantiate static data members so that
21337 their initializers are available in integral constant
21338 expressions. */
21341 }
21343 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
21344 instantiate it now, modifying TREE_TYPE (fn). */
21346 void
21348 {
21351 /* Don't instantiate a noexcept-specification from template context. */
21366 {
21370 {
21385 }
21386 else
21390 }
21393 {
21396 else
21398 }
21399 }
21401 /* Produce the definition of D, a _DECL generated from a template. If
21402 DEFER_OK is nonzero, then we don't have to actually do the
21403 instantiation now; we just have to do it sometime. Normally it is
21404 an error if this is an explicit instantiation but D is undefined.
21405 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
21406 explicitly instantiated class template. */
21408 tree
21411 {
21413 tree gen_args;
21414 tree args;
21415 tree td;
21416 tree code_pattern;
21417 tree spec;
21418 tree gen_tmpl;
21425 tree fn_context;
21428 /* This function should only be used to instantiate templates for
21429 functions and static member variables. */
21432 /* A concept is never instantiated. */
21435 /* Variables are never deferred; if instantiation is required, they
21436 are instantiated right away. That allows for better code in the
21437 case that an expression refers to the value of the variable --
21438 if the variable has a constant value the referring expression can
21439 take advantage of that fact. */
21444 /* Don't instantiate cloned functions. Instead, instantiate the
21445 functions they cloned. */
21453 /* D has already been instantiated or explicitly specialized, so
21454 there's nothing for us to do here.
21456 It might seem reasonable to check whether or not D is an explicit
21457 instantiation, and, if so, stop here. But when an explicit
21458 instantiation is deferred until the end of the compilation,
21459 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
21460 the instantiation. */
21463 /* Check to see whether we know that this template will be
21464 instantiated in some other file, as with "extern template"
21465 extension. */
21468 /* In general, we do not instantiate such templates. */
21476 /* We should already have the extra args. */
21479 /* And what's in the hash table should match D. */
21483 /* This needs to happen before any tsubsting. */
21489 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
21490 for the instantiation. */
21494 /* We should never be trying to instantiate a member of a class
21495 template or partial specialization. */
21500 /* In the case of a friend template whose definition is provided
21501 outside the class, we may have too many arguments. Drop the
21502 ones we don't need. The same is true for specializations. */
21503 args = get_innermost_template_args
21505 else
21509 {
21514 }
21515 else
21516 {
21519 }
21521 /* We may be in the middle of deferred access check. Disable it now. */
21524 /* Unless an explicit instantiation directive has already determined
21525 the linkage of D, remember that a definition is available for
21526 this entity. */
21536 /* If D is a member of an explicitly instantiated class template,
21537 and no definition is available, treat it like an implicit
21538 instantiation. */
21541 {
21542 /* Leave linkage flags alone on instantiations with anonymous
21543 visibility. */
21545 {
21548 }
21550 }
21552 /* Defer all other templates, unless we have been explicitly
21553 forbidden from doing so. */
21555 template. */
21556 ! pattern_defined
21557 /* If it's OK to postpone instantiation, do so. */
21558 || defer_ok
21559 /* If this is a static data member that will be defined
21560 elsewhere, we don't want to instantiate the entire data
21561 member, but we do want to instantiate the initializer so that
21562 we can substitute that elsewhere. */
21564 /* Handle here a deleted function too, avoid generating
21565 its body (c++/61080). */
21567 {
21568 /* The definition of the static data member is now required so
21569 we must substitute the initializer. */
21573 {
21574 tree ns;
21575 tree init;
21584 args,
21587 /* If instantiating the initializer involved instantiating this
21588 again, don't call cp_finish_decl twice. */
21590 {
21591 /* Make sure the initializer is still constant, in case of
21592 circular dependency (template/instantiate6.C). */
21593 const_init
21597 LOOKUP_ONLYCONVERTING);
21598 }
21602 }
21604 /* We restore the source position here because it's used by
21605 add_pending_template. */
21611 /* [temp.explicit]
21613 The definition of a non-exported function template, a
21614 non-exported member function template, or a non-exported
21615 member function or static data member of a class template
21616 shall be present in every translation unit in which it is
21617 explicitly instantiated. */
21621 /* If we're in unevaluated context, we just wanted to get the
21622 constant value; this isn't an odr use, so don't queue
21623 a full instantiation. */
21626 /* ??? Historically, we have instantiated inline functions, even
21627 when marked as "extern template". */
21631 }
21632 /* Tell the repository that D is available in this translation unit
21633 -- and see if it is supposed to be instantiated here. */
21635 {
21636 /* In a PCH file, despite the fact that the repository hasn't
21637 requested instantiation in the PCH it is still possible that
21638 an instantiation will be required in a file that includes the
21639 PCH. */
21642 /* Instantiate inline functions so that the inliner can do its
21643 job, even though we'll not be emitting a copy of this
21644 function. */
21647 }
21657 else
21658 {
21663 }
21665 /* Mark D as instantiated so that recursive calls to
21666 instantiate_decl do not try to instantiate it again. */
21669 /* Regenerate the declaration in case the template has been modified
21670 by a subsequent redeclaration. */
21673 /* We already set the file and line above. Reset them now in case
21674 they changed as a result of calling regenerate_decl_from_template. */
21678 {
21679 tree init;
21682 /* Clear out DECL_RTL; whatever was there before may not be right
21683 since we've reset the type of the declaration. */
21687 /* The initializer is placed in DECL_INITIAL by
21688 regenerate_decl_from_template so we don't need to
21689 push/pop_access_scope again here. Pull it out so that
21690 cp_finish_decl can process it. */
21695 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
21696 initializer. That function will defer actual emission until
21697 we have a chance to determine linkage. */
21700 /* Enter the scope of D so that access-checking works correctly. */
21713 }
21717 {
21719 tree subst_decl;
21720 tree tmpl_parm;
21721 tree spec_parm;
21724 /* Save away the current list, in case we are instantiating one
21725 template from within the body of another. */
21728 /* Set up the list of local specializations, copying the current
21729 list if there is one. */
21731 local_specializations
21733 else
21736 /* Set up context. */
21740 else
21743 /* Some typedefs referenced from within the template code need to be
21744 access checked at template instantiation time, i.e now. These
21745 types were added to the template at parsing time. Let's get those
21746 and perform the access checks then. */
21748 gen_args);
21750 /* Create substitution entries for the parameters. */
21755 {
21759 }
21761 {
21763 {
21766 }
21767 else
21768 {
21769 /* Register the (value) argument pack as a specialization of
21770 TMPL_PARM, then move on. */
21773 }
21774 }
21777 /* Substitute into the body of the function. */
21781 else
21782 {
21787 /* Set the current input_location to the end of the function
21788 so that finish_function knows where we are. */
21789 input_location
21792 /* Remember if we saw an infinite loop in the template. */
21793 current_function_infinite_loop
21795 }
21797 /* We don't need the local specializations any more. */
21801 /* Finish the function. */
21805 else
21806 {
21809 }
21813 }
21815 /* We're not deferring instantiation any more. */
21823 out:
21835 }
21837 /* Run through the list of templates that we wish we could
21838 instantiate, and instantiate any we can. RETRIES is the
21839 number of times we retry pending template instantiation. */
21841 void
21843 {
21847 /* Instantiating templates may trigger vtable generation. This in turn
21848 may require further template instantiations. We place a limit here
21849 to avoid infinite loop. */
21851 {
21855 "template instantiation depth exceeds maximum of %d"
21856 " instantiating %q+D, possibly from virtual table generation"
21860 /* Pretend that we defined it. */
21863 }
21865 do
21866 {
21871 {
21876 {
21877 tree fn;
21880 {
21884 fn;
21892 }
21895 }
21896 else
21897 {
21900 {
21901 instantiation
21907 }
21911 }
21914 /* If INSTANTIATION has been instantiated, then we don't
21915 need to consider it again in the future. */
21917 else
21918 {
21921 }
21924 }
21926 }
21930 }
21932 /* Substitute ARGVEC into T, which is a list of initializers for
21933 either base class or a non-static data member. The TREE_PURPOSEs
21934 are DECLs, and the TREE_VALUEs are the initializer values. Used by
21935 instantiate_decl. */
21937 static tree
21939 {
21943 {
21944 tree decl;
21945 tree init;
21951 {
21952 tree expr;
21953 tree arg;
21955 /* Expand the base class expansion type into separate base
21956 classes. */
21958 tf_warning_or_error,
21959 NULL_TREE);
21963 /* We'll be building separate TREE_LISTs of arguments for
21964 each base. */
21970 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
21971 expand each argument in the TREE_VALUE of t. */
21978 /* VOID_TYPE_NODE is used to indicate
21979 value-initialization. */
21980 {
21983 }
21984 else
21985 {
21986 /* Substitute parameter packs into each argument in the
21987 TREE_LIST. */
21990 {
21991 tree expanded_exprs;
21993 /* Expand the argument. */
21995 expanded_exprs
21997 tf_warning_or_error,
21998 NULL_TREE);
22002 /* Prepend each of the expanded expressions to the
22003 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
22005 {
22010 }
22011 }
22014 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
22015 since we built them backwards. */
22017 {
22020 }
22021 }
22022 }
22025 {
22027 {
22031 }
22032 else
22033 {
22034 tree tmp;
22049 /* If we had an initializer but it instantiated to nothing,
22050 value-initialize the object. This will only occur when
22051 the initializer was a pack expansion where the parameter
22052 packs used in that expansion were of length zero. */
22055 }
22058 {
22062 }
22063 }
22064 }
22066 }
22068 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
22070 static void
22072 {
22077 else
22079 }
22081 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
22082 is the instantiation (which should have been created with
22083 start_enum) and ARGS are the template arguments to use. */
22085 static void
22087 {
22088 tree e;
22094 {
22095 tree value;
22096 tree decl;
22099 /* Note that in a template enum, the TREE_VALUE is the
22100 CONST_DECL, not the corresponding INTEGER_CST. */
22105 /* Give this enumeration constant the correct access. */
22108 /* Actually build the enumerator itself. Here we're assuming that
22109 enumerators can't have dependent attributes. */
22112 }
22122 }
22124 /* DECL is a FUNCTION_DECL that is a template specialization. Return
22125 its type -- but without substituting the innermost set of template
22126 arguments. So, innermost set of template parameters will appear in
22127 the type. */
22129 tree
22131 {
22132 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
22134 }
22136 /* Return truthvalue if we're processing a template different from
22137 the last one involved in diagnostics. */
22138 bool
22140 {
22142 }
22144 /* Remember current template involved in diagnostics. */
22145 void
22147 {
22149 }
22153 {
22155 }
22157 /* Return TRUE if current_function_decl is being instantiated, false
22158 otherwise. */
22160 bool
22162 {
22165 }
22167 /* [temp.param] Check that template non-type parm TYPE is of an allowable
22168 type. Return zero for ok, nonzero for disallowed. Issue error and
22169 warning messages under control of COMPLAIN. */
22171 static int
22173 {
22188 /* A bound template template parm could later be instantiated to have a valid
22189 nontype parm type via an alias template. */
22195 {
22198 else
22200 type);
22201 }
22203 }
22205 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
22206 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
22208 static bool
22210 {
22211 tree scope;
22213 /* [temp.dep.type]
22215 A type is dependent if it is:
22217 -- a template parameter. Template template parameters are types
22218 for us (since TYPE_P holds true for them) so we handle
22219 them here. */
22223 /* -- a qualified-id with a nested-name-specifier which contains a
22224 class-name that names a dependent type or whose unqualified-id
22225 names a dependent type. */
22229 /* An alias template specialization can be dependent even if the
22230 resulting type is not. */
22234 /* -- a cv-qualified type where the cv-unqualified type is
22235 dependent.
22236 No code is necessary for this bullet; the code below handles
22237 cv-qualified types, and we don't want to strip aliases with
22238 TYPE_MAIN_VARIANT because of DR 1558. */
22239 /* -- a compound type constructed from any dependent type. */
22249 {
22250 tree arg_type;
22255 arg_type;
22260 }
22261 /* -- an array type constructed from any dependent type or whose
22262 size is specified by a constant expression that is
22263 value-dependent.
22265 We checked for type- and value-dependence of the bounds in
22266 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
22268 {
22273 }
22275 /* -- a template-id in which either the template name is a template
22276 parameter ... */
22279 /* ... or any of the template arguments is a dependent type or
22280 an expression that is type-dependent or value-dependent. */
22282 && (any_dependent_template_arguments_p
22286 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
22287 dependent; if the argument of the `typeof' expression is not
22288 type-dependent, then it should already been have resolved. */
22294 /* A template argument pack is dependent if any of its packed
22295 arguments are. */
22297 {
22303 }
22305 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
22306 be template parameters. */
22310 /* The standard does not specifically mention types that are local
22311 to template functions or local classes, but they should be
22312 considered dependent too. For example:
22314 template <int I> void f() {
22315 enum E { a = I };
22316 S<sizeof (E)> s;
22317 }
22319 The size of `E' cannot be known until the value of `I' has been
22320 determined. Therefore, `E' must be considered dependent. */
22324 /* Don't use type_dependent_expression_p here, as it can lead
22325 to infinite recursion trying to determine whether a lambda
22326 nested in a lambda is dependent (c++/47687). */
22330 && (any_dependent_template_arguments_p
22334 /* Other types are non-dependent. */
22336 }
22338 /* Returns TRUE if TYPE is dependent, in the sense of
22339 [temp.dep.type]. Note that a NULL type is considered dependent. */
22341 bool
22343 {
22344 /* If there are no template parameters in scope, then there can't be
22345 any dependent types. */
22347 {
22348 /* If we are not processing a template, then nobody should be
22349 providing us with a dependent type. */
22353 }
22355 /* If the type is NULL, we have not computed a type for the entity
22356 in question; in that case, the type is dependent. */
22360 /* Erroneous types can be considered non-dependent. */
22364 /* If we have not already computed the appropriate value for TYPE,
22365 do so now. */
22367 {
22370 }
22373 }
22375 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
22376 lookup. In other words, a dependent type that is not the current
22377 instantiation. */
22379 bool
22381 {
22384 }
22386 /* T is a SCOPE_REF; return whether we need to consider it
22387 instantiation-dependent so that we can check access at instantiation
22388 time even though we know which member it resolves to. */
22390 static bool
22392 {
22398 else
22400 }
22402 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
22403 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
22404 expression. */
22406 /* Note that this predicate is not appropriate for general expressions;
22407 only constant expressions (that satisfy potential_constant_expression)
22408 can be tested for value dependence. */
22410 bool
22412 {
22416 /* A name declared with a dependent type. */
22421 {
22423 /* A name that has not been looked up -- must be dependent. */
22427 /* A non-type template parm. */
22431 /* A non-type template parm. */
22437 /* A constant with literal type and is initialized
22438 with an expression that is value-dependent.
22440 Note that a non-dependent parenthesized initializer will have
22441 already been replaced with its constant value, so if we see
22442 a TREE_LIST it must be dependent. */
22446 /* cp_finish_decl doesn't fold reference initializers. */
22457 /* These expressions are value-dependent if the type to which
22458 the cast occurs is dependent or the expression being casted
22459 is value-dependent. */
22460 {
22466 /* A functional cast has a list of operands. */
22469 {
22470 /* If there are no operands, it must be an expression such
22471 as "int()". This should not happen for aggregate types
22472 because it would form non-constant expressions. */
22477 }
22483 }
22488 /* FALLTHRU */
22491 /* A `sizeof' expression is value-dependent if the operand is
22492 type-dependent or is a pack expansion. */
22501 /* An 'encode' expression is value-dependent if the operand is
22502 type-dependent. */
22511 /* All instantiation-dependent expressions should also be considered
22512 value-dependent. */
22520 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
22521 is value-dependent. */
22522 {
22531 }
22534 {
22538 }
22549 {
22553 }
22556 /* Treat all requires-expressions as value-dependent so
22557 we don't try to fold them. */
22564 {
22571 {
22573 /* In a call to a constexpr member function, look through the
22574 implicit ADDR_EXPR on the object argument so that it doesn't
22575 cause the call to be considered value-dependent. We also
22576 look through it in potential_constant_expression. */
22583 }
22585 }
22588 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
22589 type-dependent. */
22594 {
22596 tree val;
22603 }
22606 /* Treat a GNU statement expression as dependent to avoid crashing
22607 under instantiate_non_dependent_expr; it can't be constant. */
22611 /* A constant expression is value-dependent if any subexpression is
22612 value-dependent. */
22614 {
22621 {
22625 {
22628 /* In some cases, some of the operands may be missing.l
22629 (For example, in the case of PREDECREMENT_EXPR, the
22630 amount to increment by may be missing.) That doesn't
22631 make the expression dependent. */
22634 }
22635 }
22639 }
22641 }
22643 /* The expression is not value-dependent. */
22645 }
22647 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
22648 [temp.dep.expr]. Note that an expression with no type is
22649 considered dependent. Other parts of the compiler arrange for an
22650 expression with type-dependent subexpressions to have no type, so
22651 this function doesn't have to be fully recursive. */
22653 bool
22655 {
22662 /* An unresolved name is always dependent. */
22668 /* A fold expression is type-dependent. */
22675 /* Some expression forms are never type-dependent. */
22689 /* The types of these expressions depends only on the type to which
22690 the cast occurs. */
22699 /* The types of these expressions depends only on the type created
22700 by the expression. */
22703 {
22704 /* For NEW_EXPR tree nodes created inside a template, either
22705 the object type itself or a TREE_LIST may appear as the
22706 operand 1. */
22709 /* This is an array type. We need to check array dimensions
22710 as well. */
22712 || value_dependent_expression_p
22714 else
22716 }
22719 {
22723 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
22724 contains an identifier associated by name lookup with one or more
22725 declarations declared with a dependent type, or...a
22726 nested-name-specifier or qualified-id that names a member of an
22727 unknown specialization. */
22730 }
22735 && (any_dependent_template_arguments_p
22747 {
22748 tree elt;
22752 {
22755 }
22757 }
22759 /* A static data member of the current instantiation with incomplete
22760 array type is type-dependent, as the definition and specializations
22761 can have different bounds. */
22768 /* An array of unknown bound depending on a variadic parameter, eg:
22770 template<typename... Args>
22771 void foo (Args... args)
22772 {
22773 int arr[] = { args... };
22774 }
22776 template<int... vals>
22777 void bar ()
22778 {
22779 int arr[] = { vals... };
22780 }
22782 If the array has no length and has an initializer, it must be that
22783 we couldn't determine its length in cp_complete_array_type because
22784 it is dependent. */
22791 /* A variable template specialization is type-dependent if it has any
22792 dependent template arguments. */
22799 /* Always dependent, on the number of arguments if nothing else. */
22804 {
22809 {
22815 }
22816 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
22821 {
22826 }
22829 {
22836 }
22842 {
22846 }
22848 }
22853 }
22855 /* walk_tree callback function for instantiation_dependent_expression_p,
22856 below. Returns non-zero if a dependent subexpression is found. */
22858 static tree
22861 {
22863 {
22864 /* We don't have to worry about decltype currently because decltype
22865 of an instantiation-dependent expr is a dependent type. This
22866 might change depending on the resolution of DR 1172. */
22869 }
22872 {
22873 /* Don't treat an argument list as dependent just because it has no
22874 TREE_TYPE. */
22881 /* A constant with a dependent initializer is dependent. */
22889 /* Handle expressions with type operands. */
22894 {
22899 {
22902 else
22903 {
22906 }
22907 }
22909 }
22919 /* In a template, finish_class_member_access_expr creates a
22920 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
22921 type-dependent, so that we can check access control at
22922 instantiation time (PR 42277). See also Core issue 1273. */
22929 else
22932 /* Treat statement-expressions as dependent. */
22936 /* Treat requires-expressions as dependent. */
22941 /* Treat calls to function concepts as dependent. */
22947 /* And variable concepts. */
22954 }
22958 else
22960 }
22962 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
22963 sense defined by the ABI:
22965 "An expression is instantiation-dependent if it is type-dependent
22966 or value-dependent, or it has a subexpression that is type-dependent
22967 or value-dependent." */
22969 bool
22971 {
22972 tree result;
22983 }
22985 /* Like type_dependent_expression_p, but it also works while not processing
22986 a template definition, i.e. during substitution or mangling. */
22988 bool
22990 {
22996 }
22998 /* Returns TRUE if ARGS contains a type-dependent expression. */
23000 bool
23002 {
23004 tree arg;
23007 {
23010 }
23012 }
23014 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23015 expressions) contains any type-dependent expressions. */
23017 bool
23019 {
23025 }
23027 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23028 expressions) contains any value-dependent expressions. */
23030 bool
23032 {
23038 }
23040 /* Returns TRUE if the ARG (a template argument) is dependent. */
23042 bool
23044 {
23048 /* Assume a template argument that was wrongly written by the user
23049 is dependent. This is consistent with what
23050 any_dependent_template_arguments_p [that calls this function]
23051 does. */
23062 {
23066 {
23069 }
23072 }
23075 else
23078 }
23080 /* Returns true if ARGS (a collection of template arguments) contains
23081 any types that require structural equality testing. */
23083 bool
23085 {
23095 {
23098 {
23104 {
23105 /* Look inside the argument pack. */
23108 }
23111 {
23124 }
23125 }
23126 }
23129 }
23131 /* Returns true if ARGS (a collection of template arguments) contains
23132 any dependent arguments. */
23134 bool
23136 {
23146 {
23151 }
23154 }
23156 /* Returns TRUE if the template TMPL is dependent. */
23158 bool
23160 {
23162 {
23164 {
23168 }
23170 }
23172 /* Template template parameters are dependent. */
23176 /* So are names that have not been looked up. */
23179 /* So are member templates of dependent classes. */
23183 }
23185 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
23187 bool
23189 {
23192 }
23194 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
23195 are dependent. */
23197 bool
23199 {
23206 {
23228 {
23232 }
23236 {
23240 {
23245 }
23246 }
23247 }
23250 }
23252 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
23253 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
23254 no such TYPE can be found. Note that this function peers inside
23255 uninstantiated templates and therefore should be used only in
23256 extremely limited situations. ONLY_CURRENT_P restricts this
23257 peering to the currently open classes hierarchy (which is required
23258 when comparing types). */
23260 tree
23262 {
23263 tree scope;
23264 tree name;
23265 tree decl;
23267 tree pushed_scope;
23268 tree result;
23273 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
23274 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
23275 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
23276 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
23277 identifier of the TYPENAME_TYPE anymore.
23278 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
23279 TYPENAME_TYPE instead, we avoid messing up with a possible
23280 typedef variant case. */
23283 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
23284 it first before we can figure out what NAME refers to. */
23286 {
23288 /* Given a class template A with a dependent base with nested type C,
23289 typedef typename A::C::C C will land us here, as trying to resolve
23290 the initial A::C leads to the local C typedef, which leads back to
23291 A::C::C. So we break the recursion now. */
23293 else
23295 }
23296 /* If we don't know what SCOPE refers to, then we cannot resolve the
23297 TYPENAME_TYPE. */
23300 /* If the SCOPE is a template type parameter, we have no way of
23301 resolving the name. */
23304 /* If the SCOPE is not the current instantiation, there's no reason
23305 to look inside it. */
23308 /* If this is a typedef, we don't want to look inside (c++/11987). */
23311 /* If SCOPE isn't the template itself, it will not have a valid
23312 TYPE_FIELDS list. */
23315 /* scope is either the template itself or a compatible instantiation
23316 like X<T>, so look up the name in the original template. */
23318 else
23319 /* scope is a partial instantiation, so we can't do the lookup or we
23320 will lose the template arguments. */
23322 /* Enter the SCOPE so that name lookup will be resolved as if we
23323 were in the class definition. In particular, SCOPE will no
23324 longer be considered a dependent type. */
23326 /* Look up the declaration. */
23328 tf_warning_or_error);
23332 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
23333 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
23338 {
23342 }
23345 {
23346 tree tmpl;
23347 tree args;
23348 /* Obtain the template and the arguments. */
23351 /* Instantiate the template. */
23357 }
23359 /* Leave the SCOPE. */
23363 /* If we failed to resolve it, return the original typename. */
23367 /* If lookup found a typename type, resolve that too. */
23369 {
23370 /* Ill-formed programs can cause infinite recursion here, so we
23371 must catch that. */
23375 }
23377 /* Qualify the resulting type. */
23383 }
23385 /* EXPR is an expression which is not type-dependent. Return a proxy
23386 for EXPR that can be used to compute the types of larger
23387 expressions containing EXPR. */
23389 tree
23391 {
23392 tree inner_expr;
23394 /* Try to get a constant value for all non-dependent expressions in
23395 order to expose bugs in *_dependent_expression_p and constexpr. */
23399 /* Preserve OVERLOADs; the functions must be available to resolve
23400 types. */
23411 /* There is no need to return a proxy for a variable. */
23414 /* Preserve string constants; conversions from string constants to
23415 "char *" are allowed, even though normally a "const char *"
23416 cannot be used to initialize a "char *". */
23419 /* Preserve void and arithmetic constants, as an optimization -- there is no
23420 reason to create a new node. */
23425 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
23426 There is at least one place where we want to know that a
23427 particular expression is a throw-expression: when checking a ?:
23428 expression, there are special rules if the second or third
23429 argument is a throw-expression. */
23433 /* Don't wrap an initializer list, we need to be able to look inside. */
23437 /* Don't wrap a dummy object, we need to be able to test for it. */
23456 /* If the type is unknown, it can't really be non-dependent */
23459 /* Otherwise, build a NON_DEPENDENT_EXPR. */
23461 }
23463 /* ARGS is a vector of expressions as arguments to a function call.
23464 Replace the arguments with equivalent non-dependent expressions.
23465 This modifies ARGS in place. */
23467 void
23469 {
23471 tree arg;
23474 {
23478 }
23479 }
23481 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
23482 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
23483 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
23485 static tree
23487 {
23501 }
23503 tree
23505 {
23507 }
23509 tree
23511 {
23513 }
23515 /* Make a "constrained auto" type-specifier. This is an
23516 auto type with constraints that must be associated after
23517 deduction. The constraint is formed from the given
23518 CONC and its optional sequence of arguments, which are
23519 non-null if written as partial-concept-id. */
23521 tree
23523 {
23526 /* Build the constraint. */
23528 tree expr;
23531 else
23537 /* Our canonical type depends on the constraint. */
23540 /* Attach the constraint to the type declaration. */
23543 }
23545 /* Given type ARG, return std::initializer_list<ARG>. */
23547 static tree
23549 {
23550 tree std_init_list = namespace_binding
23552 tree argvec;
23554 {
23558 }
23563 }
23565 /* Replace auto in TYPE with std::initializer_list<auto>. */
23567 static tree
23569 {
23576 }
23578 /* Hash traits for hashing possibly constrained 'auto'
23579 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
23582 {
23585 };
23587 /* Hash the 'auto' T. */
23589 inline hashval_t
23591 {
23593 /* Matching constrained-type-specifiers denote the same template
23594 parameter, so hash the constraint. */
23596 else
23597 /* But unconstrained autos are all separate, so just hash the pointer. */
23599 }
23601 /* Compare two 'auto's. */
23605 {
23612 /* Two unconstrained autos are distinct. */
23617 }
23619 /* for_each_template_parm callback for extract_autos: if t is a (possibly
23620 constrained) auto, add it to the vector. */
23622 static int
23624 {
23627 {
23628 /* All the autos were built with index 0; fix that up now. */
23632 /* If this is a repeated constrained-type-specifier, use the index we
23633 chose before. */
23635 else
23636 {
23637 /* Otherwise this is new, so use the current count. */
23640 }
23642 }
23644 /* Always keep walking. */
23646 }
23648 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
23649 says they can appear anywhere in the type. */
23651 static tree
23653 {
23662 {
23667 }
23670 }
23672 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
23673 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
23675 tree
23677 {
23679 tf_warning_or_error,
23680 adc_unspecified);
23681 }
23683 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
23684 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
23685 The CONTEXT determines the context in which auto deduction is performed
23686 and is used to control error diagnostics. */
23688 tree
23691 {
23692 tree targs;
23698 /* Defining a subset of type-dependent expressions that we can deduce
23699 from ahead of time isn't worth the trouble. */
23702 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
23703 with either a new invented type template parameter U or, if the
23704 initializer is a braced-init-list (8.5.4), with
23705 std::initializer_list<U>. */
23707 {
23712 else
23713 {
23715 {
23719 "for deduction to %<std::initializer_list%>, use copy-"
23721 }
23723 }
23724 }
23732 {
23739 {
23743 }
23744 }
23745 else
23746 {
23748 tree tparms;
23752 else
23753 {
23757 }
23764 {
23766 /* Try again at instantiation time. */
23770 /* If type is error_mark_node a diagnostic must have been
23771 emitted by now. Also, having a mention to '<type error>'
23772 in the diagnostic is not really useful to the user. */
23773 {
23777 else
23782 }
23784 }
23785 }
23787 /* Check any placeholder constraints against the deduced type. */
23790 {
23791 /* Use the deduced type to check the associated constraints. */
23793 {
23795 {
23797 {
23813 }
23815 }
23817 }
23818 }
23823 }
23825 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
23826 result. */
23828 tree
23830 {
23832 {
23838 /* In an abbreviated function template we didn't know we were dealing
23839 with a function template when we saw the auto return type, so update
23840 it to have the correct level. */
23842 }
23844 }
23846 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
23847 'decltype(auto)'. */
23849 bool
23851 {
23856 else
23858 }
23860 /* for_each_template_parm callback for type_uses_auto. */
23862 int
23864 {
23866 }
23868 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
23869 a use of `auto'. Returns NULL_TREE otherwise. */
23871 tree
23873 {
23877 {
23878 /* The Concepts TS allows multiple autos in one type-specifier; just
23879 return the first one we find, do_auto_deduction will collect all of
23880 them. */
23884 else
23886 }
23887 else
23889 }
23891 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
23892 'decltype(auto)' or a concept. */
23894 bool
23896 {
23898 }
23900 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
23901 a concept identifier) iff TYPE contains a use of a generic type. Returns
23902 NULL_TREE otherwise. */
23904 tree
23906 {
23908 }
23911 /* For a given template T, return the vector of typedefs referenced
23912 in T for which access check is needed at T instantiation time.
23913 T is either a FUNCTION_DECL or a RECORD_TYPE.
23914 Those typedefs were added to T by the function
23915 append_type_to_template_for_access_check. */
23919 {
23920 tree ti;
23931 {
23936 }
23939 }
23941 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
23942 tied to T. That list of typedefs will be access checked at
23943 T instantiation time.
23944 T is either a FUNCTION_DECL or a RECORD_TYPE.
23945 TYPE_DECL is a TYPE_DECL node representing a typedef.
23946 SCOPE is the scope through which TYPE_DECL is accessed.
23947 LOCATION is the location of the usage point of TYPE_DECL.
23949 This function is a subroutine of
23950 append_type_to_template_for_access_check. */
23952 static void
23954 tree type_decl,
23955 tree scope,
23956 location_t location)
23957 {
23958 qualified_typedef_usage_t typedef_usage;
23959 tree ti;
23966 && type_decl
23980 }
23982 /* Append TYPE_DECL to the template TEMPL.
23983 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
23984 At TEMPL instanciation time, TYPE_DECL will be checked to see
23985 if it can be accessed through SCOPE.
23986 LOCATION is the location of the usage point of TYPE_DECL.
23988 e.g. consider the following code snippet:
23990 class C
23991 {
23992 typedef int myint;
23993 };
23995 template<class U> struct S
23996 {
23997 C::myint mi; // <-- usage point of the typedef C::myint
23998 };
24000 S<char> s;
24002 At S<char> instantiation time, we need to check the access of C::myint
24003 In other words, we need to check the access of the myint typedef through
24004 the C scope. For that purpose, this function will add the myint typedef
24005 and the scope C through which its being accessed to a list of typedefs
24006 tied to the template S. That list will be walked at template instantiation
24007 time and access check performed on each typedefs it contains.
24008 Note that this particular code snippet should yield an error because
24009 myint is private to C. */
24011 void
24013 tree type_decl,
24014 tree scope,
24015 location_t location)
24016 {
24022 /* Make sure we don't append the type to the template twice. */
24029 }
24031 /* Convert the generic type parameters in PARM that match the types given in the
24032 range [START_IDX, END_IDX) from the current_template_parms into generic type
24033 packs. */
24035 tree
24037 {
24048 {
24049 /* Create a distinct parameter pack type from the current parm and add it
24050 to the replacement args to tsubst below into the generic function
24051 parameter. */
24066 }
24072 /* If there are more levels then build up the replacement with the outer
24073 template parms. */
24077 replacement);
24080 }
24082 /* Entries in the decl_constraint hash table. */
24084 {
24085 tree decl;
24086 tree ci;
24087 };
24089 /* Hashing function and equality for constraint entries. */
24091 {
24093 {
24095 }
24098 {
24100 }
24101 };
24103 /* A mapping from declarations to constraint information. Note that
24104 both templates and their underlying declarations are mapped to the
24105 same constraint information.
24107 FIXME: This is defined in pt.c because garbage collection
24108 code is not being generated for constraint.cc. */
24112 /* Returns true iff cinfo contains a valid set of constraints.
24113 This is the case when the associated requirements have been
24114 successfully decomposed into lists of atomic constraints.
24115 That is, when the saved assumptions are not error_mark_node. */
24117 bool
24119 {
24122 }
24124 /* Returns the template constraints of declaration T. If T is not
24125 constrained, return NULL_TREE. Note that T must be non-null. */
24127 tree
24129 {
24137 else
24139 }
24141 /* Associate the given constraint information CI with the declaration
24142 T. If T is a template, then the constraints are associated with
24143 its underlying declaration. Don't build associations if CI is
24144 NULL_TREE. */
24146 void
24148 {
24160 }
24162 /* Remove the associated constraints of the declaration T. */
24164 void
24166 {
24175 }
24177 /* Set up the hash table for constraint association. */
24179 void
24181 {
24183 }
24185 /* Set up the hash tables for template instantiations. */
24187 void
24189 {
24192 }
24194 /* Print stats about the template hash tables for -fstats. */
24196 void
24198 {
24207 }