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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". */
59 /* The type of functions taking a tree, and some additional data, and
60 returning an int. */
63 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
64 instantiations have been deferred, either because their definitions
65 were not yet available, or because we were putting off doing the work. */
69 };
84 /* Live only within one (recursive) call to tsubst_expr. We use
85 this to pass the statement expression node from the STMT_EXPR
86 to the EXPR_STMT that is its result. */
89 /* True if we've recursed into fn_type_unification too many times. */
93 {
94 tree tmpl;
95 tree args;
96 tree spec;
97 };
100 {
103 };
109 /* Contains canonical template parameter types. The vector is indexed by
110 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
111 TREE_LIST, whose TREE_VALUEs contain the canonical template
112 parameters of various types and levels. */
115 #define UNIFY_ALLOW_NONE 0
116 #define UNIFY_ALLOW_MORE_CV_QUAL 1
117 #define UNIFY_ALLOW_LESS_CV_QUAL 2
118 #define UNIFY_ALLOW_DERIVED 4
119 #define UNIFY_ALLOW_INTEGER 8
120 #define UNIFY_ALLOW_OUTER_LEVEL 16
121 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
122 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
125 tbr_incomplete_type,
126 tbr_ambiguous_baseclass,
127 tbr_success
128 };
151 tree);
213 location_t);
222 /* Make the current scope suitable for access checking when we are
223 processing T. T can be FUNCTION_DECL for instantiated function
224 template, VAR_DECL for static member variable, or TYPE_DECL for
225 alias template (needed by instantiate_decl). */
227 static void
229 {
237 else
241 {
242 saved_access_scope = tree_cons
245 }
246 }
248 /* Restore the scope set up by push_access_scope. T is the node we
249 are processing. */
251 static void
253 {
255 {
258 }
262 else
264 }
266 /* Do any processing required when DECL (a member template
267 declaration) is finished. Returns the TEMPLATE_DECL corresponding
268 to DECL, unless it is a specialization, in which case the DECL
269 itself is returned. */
271 tree
273 {
280 {
281 tree type;
289 {
293 }
295 }
299 {
301 {
304 }
305 else
307 }
308 else
312 }
314 /* Create a template info node. */
316 tree
318 {
323 }
325 /* Return the template info node corresponding to T, whatever T is. */
327 tree
329 {
350 }
352 /* Returns the template nesting level of the indicated class TYPE.
354 For example, in:
355 template <class T>
356 struct A
357 {
358 template <class U>
359 struct B {};
360 };
362 A<T>::B<U> has depth two, while A<T> has depth one.
363 Both A<T>::B<int> and A<int>::B<U> have depth one, if
364 they are instantiations, not specializations.
366 This function is guaranteed to return 0 if passed NULL_TREE so
367 that, for example, `template_class_depth (current_class_type)' is
368 always safe. */
370 int
372 {
379 {
385 }
388 }
390 /* Subroutine of maybe_begin_member_template_processing.
391 Returns true if processing DECL needs us to push template parms. */
393 static bool
395 {
401 }
403 /* Subroutine of maybe_begin_member_template_processing.
404 Push the template parms in PARMS, starting from LEVELS steps into the
405 chain, and ending at the beginning, since template parms are listed
406 innermost first. */
408 static void
410 {
418 current_template_parms
424 NULL);
426 {
435 {
442 {
443 /* Make a CONST_DECL as is done in process_template_parm.
444 It is ugly that we recreate this here; the original
445 version built in process_template_parm is no longer
446 available. */
456 }
461 }
462 }
463 }
465 /* Restore the template parameter context for a member template, a
466 friend template defined in a class definition, or a non-template
467 member of template class. */
469 void
471 {
472 tree parms;
477 {
480 /* Disregard full specializations (c++/60999). */
483 }
486 {
491 {
494 }
497 }
499 /* Remember how many levels of template parameters we pushed so that
500 we can pop them later. */
502 }
504 /* Undo the effects of maybe_begin_member_template_processing. */
506 void
508 {
517 {
521 }
522 }
524 /* Return a new template argument vector which contains all of ARGS,
525 but has as its innermost set of arguments the EXTRA_ARGS. */
527 static tree
529 {
530 tree new_args;
548 }
550 /* Like add_to_template_args, but only the outermost ARGS are added to
551 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
552 (EXTRA_ARGS) levels are added. This function is used to combine
553 the template arguments from a partial instantiation with the
554 template arguments used to attain the full instantiation from the
555 partial instantiation. */
557 static tree
559 {
560 tree new_args;
562 /* If there are more levels of EXTRA_ARGS than there are ARGS,
563 something very fishy is going on. */
566 /* If *all* the new arguments will be the EXTRA_ARGS, just return
567 them. */
571 /* For the moment, we make ARGS look like it contains fewer levels. */
576 /* Now, we restore ARGS to its full dimensions. */
580 }
582 /* Return the N levels of innermost template arguments from the ARGS. */
584 tree
586 {
587 tree new_args;
593 /* If N is 1, just return the innermost set of template arguments. */
597 /* If we're not removing anything, just return the arguments we were
598 given. */
604 /* Make a new set of arguments, not containing the outer arguments. */
611 }
613 /* The inverse of get_innermost_template_args: Return all but the innermost
614 EXTRA_LEVELS levels of template arguments from the ARGS. */
616 static tree
618 {
619 tree new_args;
625 /* If N is 1, just return the outermost set of template arguments. */
629 /* If we're not removing anything, just return the arguments we were
630 given. */
635 /* Make a new set of arguments, not containing the inner arguments. */
642 }
644 /* We've got a template header coming up; push to a new level for storing
645 the parms. */
647 void
649 {
650 /* We use a non-tag-transparent scope here, which causes pushtag to
651 put tags in this scope, rather than in the enclosing class or
652 namespace scope. This is the right thing, since we want
653 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
654 global template class, push_template_decl handles putting the
655 TEMPLATE_DECL into top-level scope. For a nested template class,
656 e.g.:
658 template <class T> struct S1 {
659 template <class T> struct S2 {};
660 };
662 pushtag contains special code to call pushdecl_with_scope on the
663 TEMPLATE_DECL for S2. */
668 }
670 /* This routine is called when a specialization is declared. If it is
671 invalid to declare a specialization here, an error is reported and
672 false is returned, otherwise this routine will return true. */
674 static bool
676 {
679 /* [temp.expl.spec]
681 An explicit specialization shall be declared in the namespace of
682 which the template is a member, or, for member templates, in the
683 namespace of which the enclosing class or enclosing class
684 template is a member. An explicit specialization of a member
685 function, member class or static data member of a class template
686 shall be declared in the namespace of which the class template
687 is a member. */
689 {
692 }
694 /* [temp.expl.spec]
696 In an explicit specialization declaration for a member of a class
697 template or a member template that appears in namespace scope,
698 the member template and some of its enclosing class templates may
699 remain unspecialized, except that the declaration shall not
700 explicitly specialize a class member template if its enclosing
701 class templates are not explicitly specialized as well. */
703 {
706 }
709 }
711 /* We've just seen template <>. */
713 bool
715 {
719 }
721 /* Called at then end of processing a declaration preceded by
722 template<>. */
724 void
726 {
729 }
731 /* Any template <>'s that we have seen thus far are not referring to a
732 function specialization. */
734 void
736 {
739 }
741 /* We've just seen a template header. If SPECIALIZATION is nonzero,
742 it was of the form template <>. */
744 static void
746 {
748 template_header_count++;
749 }
751 /* We're beginning an explicit instantiation. */
753 void
755 {
758 }
761 void
763 {
766 }
768 /* An explicit specialization or partial specialization of TMPL is being
769 declared. Check that the namespace in which the specialization is
770 occurring is permissible. Returns false iff it is invalid to
771 specialize TMPL in the current namespace. */
773 static bool
775 {
778 /* [tmpl.expl.spec]
780 An explicit specialization shall be declared in the namespace of
781 which the template is a member, or, for member templates, in the
782 namespace of which the enclosing class or enclosing class
783 template is a member. An explicit specialization of a member
784 function, member class or static data member of a class template
785 shall be declared in the namespace of which the class template is
786 a member. */
789 {
792 }
794 /* Same or super-using namespace. */
796 else
797 {
801 }
802 }
804 /* SPEC is an explicit instantiation. Check that it is valid to
805 perform this explicit instantiation in the current namespace. */
807 static void
809 {
810 tree ns;
812 /* DR 275: An explicit instantiation shall appear in an enclosing
813 namespace of its template. */
819 }
821 /* The TYPE is being declared. If it is a template type, that means it
822 is a partial specialization. Do appropriate error-checking. */
824 tree
826 {
827 tree context;
832 /* A lambda that appears in specialization context is not itself a
833 specialization. */
838 {
842 }
847 {
852 else
855 }
857 {
858 /* This is for ordinary explicit specialization and partial
859 specialization of a template class such as:
861 template <> class C<int>;
863 or:
865 template <class T> class C<T*>;
867 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
871 {
878 {
882 }
883 }
889 /* Trying to define a specialization either without a template<> header
890 or in an inappropriate place. We've already given an error, so just
891 bail now so we don't actually define the specialization. */
893 }
899 {
900 /* This is for an explicit specialization of member class
901 template according to [temp.expl.spec/18]:
903 template <> template <class U> class C<int>::D;
905 The context `C<int>' must be an implicit instantiation.
906 Otherwise this is just a member class template declared
907 earlier like:
909 template <> class C<int> { template <class U> class D; };
910 template <> template <class U> class C<int>::D;
912 In the first case, `C<int>::D' is a specialization of `C<T>::D'
913 while in the second case, `C<int>::D' is a primary template
914 and `C<T>::D' may not exist. */
918 {
919 tree t;
924 {
927 }
929 /* Check for invalid specialization after instantiation:
931 template <> template <> class C<int>::D<int>;
932 template <> template <class U> class C<int>::D; */
936 {
940 {
941 /* We already have a full specialization of this partial
942 instantiation, or a full specialization has been
943 looked up but not instantiated. Reassign it to the
944 new member specialization template. */
945 spec_entry elt;
957 spec_entry **slot
962 }
963 else
964 /* But if we've had an implicit instantiation, that's a
965 problem ([temp.expl.spec]/6). */
968 }
970 /* Mark TYPE as a specialization. And as a result, we only
971 have one level of template argument for the innermost
972 class template. */
977 }
978 }
980 {
981 /* Someday C++0x may allow for enum template specialization. */
986 else
987 {
990 }
991 }
994 }
996 /* Returns nonzero if we can optimize the retrieval of specializations
997 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
998 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1002 {
1005 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1006 parameter. */
1008 /* The optimized lookup depends on the fact that the
1009 template arguments for the member function template apply
1010 purely to the containing class, which is not true if the
1011 containing class is an explicit or partial
1012 specialization. */
1016 /* It is possible to have a template that is not a member
1017 template and is not a member of a template class:
1019 template <typename T>
1020 struct S { friend A::f(); };
1022 Here, the friend function is a template, but the context does
1023 not have template information. The optimized lookup relies
1024 on having ARGS be the template arguments for both the class
1025 and the function template. */
1027 }
1029 /* Retrieve the specialization (in the sense of [temp.spec] - a
1030 specialization is either an instantiation or an explicit
1031 specialization) of TMPL for the given template ARGS. If there is
1032 no such specialization, return NULL_TREE. The ARGS are a vector of
1033 arguments, or a vector of vectors of arguments, in the case of
1034 templates with more than one level of parameters.
1036 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1037 then we search for a partial specialization matching ARGS. This
1038 parameter is ignored if TMPL is not a class template.
1040 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1041 result is a NONTYPE_ARGUMENT_PACK. */
1043 static tree
1045 {
1055 /* There should be as many levels of arguments as there are
1056 levels of parameters. */
1063 {
1064 tree class_template;
1065 tree class_specialization;
1067 tree fns;
1070 /* The template arguments actually apply to the containing
1071 class. Find the class specialization with those
1072 arguments. */
1074 class_specialization
1078 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1079 for the specialization. */
1083 /* Iterate through the methods with the indicated name, looking
1084 for the one that has an instance of TMPL. */
1087 {
1090 /* using-declarations can add base methods to the method vec,
1091 and we don't want those here. */
1094 }
1096 }
1097 else
1098 {
1100 spec_entry elt;
1109 else
1117 }
1120 }
1122 /* Like retrieve_specialization, but for local declarations. */
1124 static tree
1126 {
1132 }
1134 /* Returns nonzero iff DECL is a specialization of TMPL. */
1136 int
1138 {
1139 tree t;
1142 {
1148 }
1149 else
1150 {
1159 }
1162 }
1164 /* Returns nonzero iff DECL is a specialization of friend declaration
1165 FRIEND_DECL according to [temp.friend]. */
1167 bool
1169 {
1176 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1177 of a template class, we want to check if DECL is a specialization
1178 if this. */
1182 {
1183 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1186 }
1191 /* There is nothing to do if this is not a template friend. */
1198 /* [temp.friend/6]
1199 A member of a class template may be declared to be a friend of a
1200 non-template class. In this case, the corresponding member of
1201 every specialization of the class template is a friend of the
1202 class granting friendship.
1204 For example, given a template friend declaration
1206 template <class T> friend void A<T>::f();
1208 the member function below is considered a friend
1210 template <> struct A<int> {
1211 void f();
1212 };
1214 For this type of template friend, TEMPLATE_DEPTH below will be
1215 nonzero. To determine if DECL is a friend of FRIEND, we first
1216 check if the enclosing class is a specialization of another. */
1223 {
1224 /* Next, we check the members themselves. In order to handle
1225 a few tricky cases, such as when FRIEND_DECL's are
1227 template <class T> friend void A<T>::g(T t);
1228 template <class T> template <T t> friend void A<T>::h();
1230 and DECL's are
1232 void A<int>::g(int);
1233 template <int> void A<int>::h();
1235 we need to figure out ARGS, the template arguments from
1236 the context of DECL. This is required for template substitution
1237 of `T' in the function parameter of `g' and template parameter
1238 of `h' in the above examples. Here ARGS corresponds to `int'. */
1245 {
1247 {
1250 else
1252 current_depth++;
1253 }
1255 }
1258 {
1260 tree friend_type;
1261 tree decl_type;
1262 tree friend_args_type;
1263 tree decl_args_type;
1265 /* Make sure that both DECL and FRIEND_DECL are templates or
1266 non-templates. */
1272 {
1273 /* If both are templates, check template parameter list. */
1274 tree friend_parms
1279 friend_parms))
1283 }
1284 else
1292 /* Check if return types match. */
1296 /* Check if function parameter types match, ignoring the
1297 `this' parameter. */
1306 }
1307 else
1308 {
1309 /* DECL is a TYPE_DECL */
1313 /* Make sure that both DECL and FRIEND_DECL are templates or
1314 non-templates. */
1315 is_template
1322 {
1323 tree friend_parms;
1324 /* If both are templates, check the name of the two
1325 TEMPLATE_DECL's first because is_friend didn't. */
1330 /* Now check template parameter list. */
1331 friend_parms
1334 return comp_template_parms
1336 friend_parms);
1337 }
1338 else
1341 }
1342 }
1344 }
1346 /* Register the specialization SPEC as a specialization of TMPL with
1347 the indicated ARGS. IS_FRIEND indicates whether the specialization
1348 is actually just a friend declaration. Returns SPEC, or an
1349 equivalent prior declaration, if available.
1351 We also store instantiations of field packs in the hash table, even
1352 though they are not themselves templates, to make lookup easier. */
1354 static tree
1356 hashval_t hash)
1357 {
1358 tree fn;
1360 spec_entry elt;
1368 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1369 register it; we want the corresponding TEMPLATE_DECL instead.
1370 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1371 the more obvious `uses_template_parms (spec)' to avoid problems
1372 with default function arguments. In particular, given
1373 something like this:
1375 template <class T> void f(T t1, T t = T())
1377 the default argument expression is not substituted for in an
1378 instantiation unless and until it is actually needed. */
1382 /* We don't put these specializations in the hash table, but we might
1383 want to give an error about a mismatch. */
1385 else
1386 {
1394 slot =
1398 else
1400 }
1402 /* We can sometimes try to re-register a specialization that we've
1403 already got. In particular, regenerate_decl_from_template calls
1404 duplicate_decls which will update the specialization list. But,
1405 we'll still get called again here anyhow. It's more convenient
1406 to simply allow this than to try to prevent it. */
1410 {
1412 {
1415 {
1417 fn);
1419 }
1420 else
1421 {
1422 tree clone;
1423 /* This situation should occur only if the first
1424 specialization is an implicit instantiation, the
1425 second is an explicit specialization, and the
1426 implicit instantiation has not yet been used. That
1427 situation can occur if we have implicitly
1428 instantiated a member function and then specialized
1429 it later.
1431 We can also wind up here if a friend declaration that
1432 looked like an instantiation turns out to be a
1433 specialization:
1435 template <class T> void foo(T);
1436 class S { friend void foo<>(int) };
1437 template <> void foo(int);
1439 We transform the existing DECL in place so that any
1440 pointers to it become pointers to the updated
1441 declaration.
1443 If there was a definition for the template, but not
1444 for the specialization, we want this to look as if
1445 there were no definition, and vice versa. */
1448 /* The call to duplicate_decls will have applied
1449 [temp.expl.spec]:
1451 An explicit specialization of a function template
1452 is inline only if it is explicitly declared to be,
1453 and independently of whether its function template
1454 is.
1456 to the primary function; now copy the inline bits to
1457 the various clones. */
1459 {
1466 }
1470 }
1471 }
1473 {
1475 /* Dup decl failed, but this is a new definition. Set the
1476 line number so any errors match this new
1477 definition. */
1481 }
1482 }
1486 /* A specialization must be declared in the same namespace as the
1487 template it is specializing. */
1493 {
1502 /* If TMPL is a forward declaration of a template function, keep a list
1503 of all specializations in case we need to reassign them to a friend
1504 template later in tsubst_friend_function.
1506 Also keep a list of all variable template instantiations so that
1507 process_partial_specialization can check whether a later partial
1508 specialization would have used it. */
1511 }
1514 }
1516 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1517 TMPL and ARGS members, ignores SPEC. */
1521 bool
1523 {
1532 }
1534 /* Returns a hash for a template TMPL and template arguments ARGS. */
1536 static hashval_t
1538 {
1541 }
1543 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1544 ignoring SPEC. */
1546 hashval_t
1548 {
1550 }
1552 /* Recursively calculate a hash value for a template argument ARG, for use
1553 in the hash tables of template specializations. */
1555 hashval_t
1557 {
1569 /* We can get one of these when re-hashing a previous entry in the middle
1570 of substituting into a pack expansion. Just look through it. */
1579 {
1587 {
1592 }
1614 {
1618 {
1621 }
1623 }
1627 {
1630 }
1641 val = iterative_hash_template_arg
1653 val);
1655 val);
1664 /* A lambda can't appear in a template arg, but don't crash on
1665 erroneous input. */
1677 /* Now hash operands as usual. */
1682 }
1685 {
1688 {
1689 // We want an alias specialization that survived strip_typedefs
1690 // to hash differently from its TYPE_CANONICAL, to avoid hash
1691 // collisions that compare as different in template_args_equal.
1692 // These could be dependent specializations that strip_typedefs
1693 // left alone, or untouched specializations because
1694 // coerce_template_parms returns the unconverted template
1695 // arguments if it sees incomplete argument packs.
1698 }
1701 val);
1704 /* Otherwise just compare the types during lookup. */
1713 {
1718 }
1719 }
1722 }
1724 /* Unregister the specialization SPEC as a specialization of TMPL.
1725 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1726 if the SPEC was listed as a specialization of TMPL.
1728 Note that SPEC has been ggc_freed, so we can't look inside it. */
1730 bool
1732 {
1734 spec_entry elt;
1742 {
1747 }
1750 }
1752 /* Like register_specialization, but for local declarations. We are
1753 registering SPEC, an instantiation of TMPL. */
1755 static void
1757 {
1759 }
1761 /* TYPE is a class type. Returns true if TYPE is an explicitly
1762 specialized class. */
1764 bool
1766 {
1770 }
1772 /* Print the list of functions at FNS, going through all the overloads
1773 for each element of the list. Alternatively, FNS can not be a
1774 TREE_LIST, in which case it will be printed together with all the
1775 overloads.
1777 MORE and *STR should respectively be FALSE and NULL when the function
1778 is called from the outside. They are used internally on recursive
1779 calls. print_candidates manages the two parameters and leaves NULL
1780 in *STR when it ends. */
1782 static void
1784 {
1790 {
1794 }
1795 else
1796 {
1799 {
1800 /* Pick the prefix string. */
1802 {
1806 }
1810 }
1813 }
1816 {
1819 }
1820 }
1822 /* Print the list of candidate FNS in an error message. FNS can also
1823 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1825 void
1827 {
1831 }
1833 /* Returns the template (one of the functions given by TEMPLATE_ID)
1834 which can be specialized to match the indicated DECL with the
1835 explicit template args given in TEMPLATE_ID. The DECL may be
1836 NULL_TREE if none is available. In that case, the functions in
1837 TEMPLATE_ID are non-members.
1839 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1840 specialization of a member template.
1842 The TEMPLATE_COUNT is the number of references to qualifying
1843 template classes that appeared in the name of the function. See
1844 check_explicit_specialization for a more accurate description.
1846 TSK indicates what kind of template declaration (if any) is being
1847 declared. TSK_TEMPLATE indicates that the declaration given by
1848 DECL, though a FUNCTION_DECL, has template parameters, and is
1849 therefore a template function.
1851 The template args (those explicitly specified and those deduced)
1852 are output in a newly created vector *TARGS_OUT.
1854 If it is impossible to determine the result, an error message is
1855 issued. The error_mark_node is returned to indicate failure. */
1857 static tree
1859 tree decl,
1863 tmpl_spec_kind tsk)
1864 {
1865 tree fns;
1866 tree targs;
1867 tree explicit_targs;
1869 /* A TREE_LIST of templates of which DECL may be a specialization.
1870 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1871 corresponding TREE_PURPOSE is the set of template arguments that,
1872 when used to instantiate the template, would produce a function
1873 with the signature of DECL. */
1883 /* We shouldn't be specializing a member template of an
1884 unspecialized class template; we already gave an error in
1885 check_specialization_scope, now avoid crashing. */
1888 {
1891 }
1899 /* Check for baselinks. */
1904 {
1907 }
1909 {
1912 }
1914 /* Count the number of template headers specified for this
1915 specialization. */
1923 {
1926 tf_warning_or_error,
1929 }
1931 {
1935 {
1936 tree decl_arg_types;
1937 tree fn_arg_types;
1938 tree insttype;
1940 /* In case of explicit specialization, we need to check if
1941 the number of template headers appearing in the specialization
1942 is correct. This is usually done in check_explicit_specialization,
1943 but the check done there cannot be exhaustive when specializing
1944 member functions. Consider the following code:
1946 template <> void A<int>::f(int);
1947 template <> template <> void A<int>::f(int);
1949 Assuming that A<int> is not itself an explicit specialization
1950 already, the first line specializes "f" which is a non-template
1951 member function, whilst the second line specializes "f" which
1952 is a template member function. So both lines are syntactically
1953 correct, and check_explicit_specialization does not reject
1954 them.
1956 Here, we can do better, as we are matching the specialization
1957 against the declarations. We count the number of template
1958 headers, and we check if they match TEMPLATE_COUNT + 1
1959 (TEMPLATE_COUNT is the number of qualifying template classes,
1960 plus there must be another header for the member template
1961 itself).
1963 Notice that if header_count is zero, this is not a
1964 specialization but rather a template instantiation, so there
1965 is no check we can perform here. */
1969 /* Check that the number of template arguments at the
1970 innermost level for DECL is the same as for FN. */
1978 /* DECL might be a specialization of FN. */
1982 /* For a non-static member function, we need to make sure
1983 that the const qualification is the same. Since
1984 get_bindings does not try to merge the "this" parameter,
1985 we must do the comparison explicitly. */
1991 /* Skip the "this" parameter and, for constructors of
1992 classes with virtual bases, the VTT parameter. A
1993 full specialization of a constructor will have a VTT
1994 parameter, but a template never will. */
1995 decl_arg_types
1997 fn_arg_types
2000 /* Function templates cannot be specializations; there are
2001 no partial specializations of functions. Therefore, if
2002 the type of DECL does not match FN, there is no
2003 match. */
2005 {
2009 }
2011 /* See whether this function might be a specialization of this
2012 template. Suppress access control because we might be trying
2013 to make this specialization a friend, and we have already done
2014 access control for the declaration of the specialization. */
2020 /* We cannot deduce template arguments that when used to
2021 specialize TMPL will produce DECL. */
2024 /* Make sure that the deduced arguments actually work. */
2028 fn_arg_types
2033 /* Save this template, and the arguments deduced. */
2035 }
2037 /* FN is an ordinary member function, and we need a
2038 specialization of a member template. */
2039 ;
2041 /* We can get IDENTIFIER_NODEs here in certain erroneous
2042 cases. */
2043 ;
2045 /* This is just an ordinary non-member function. Nothing can
2046 be a specialization of that. */
2047 ;
2049 /* Cannot specialize functions that are created implicitly. */
2050 ;
2051 else
2052 {
2053 tree decl_arg_types;
2055 /* This is an ordinary member function. However, since
2056 we're here, we can assume its enclosing class is a
2057 template class. For example,
2059 template <typename T> struct S { void f(); };
2060 template <> void S<int>::f() {}
2062 Here, S<int>::f is a non-template, but S<int> is a
2063 template class. If FN has the same type as DECL, we
2064 might be in business. */
2067 /* Its enclosing class is an explicit specialization
2068 of a template class. This is not a candidate. */
2073 /* The return types differ. */
2076 /* Adjust the type of DECL in case FN is a static member. */
2083 decl_arg_types))
2084 /* They match! */
2086 }
2087 }
2090 {
2091 /* We have:
2093 [temp.expl.spec]
2095 It is possible for a specialization with a given function
2096 signature to be instantiated from more than one function
2097 template. In such cases, explicit specification of the
2098 template arguments must be used to uniquely identify the
2099 function template specialization being specialized.
2101 Note that here, there's no suggestion that we're supposed to
2102 determine which of the candidate templates is most
2103 specialized. However, we, also have:
2105 [temp.func.order]
2107 Partial ordering of overloaded function template
2108 declarations is used in the following contexts to select
2109 the function template to which a function template
2110 specialization refers:
2112 -- when an explicit specialization refers to a function
2113 template.
2115 So, we do use the partial ordering rules, at least for now.
2116 This extension can only serve to make invalid programs valid,
2117 so it's safe. And, there is strong anecdotal evidence that
2118 the committee intended the partial ordering rules to apply;
2119 the EDG front end has that behavior, and John Spicer claims
2120 that the committee simply forgot to delete the wording in
2121 [temp.expl.spec]. */
2124 {
2127 }
2128 }
2131 {
2139 }
2143 {
2149 }
2151 /* We have one, and exactly one, match. */
2153 {
2156 /* DECL is a re-declaration or partial instantiation of a template
2157 function. */
2160 /* It was a specialization of an ordinary member function in a
2161 template class. */
2163 }
2165 /* It was a specialization of a template. */
2168 {
2173 }
2174 else
2177 }
2179 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2180 but with the default argument values filled in from those in the
2181 TMPL_TYPES. */
2183 static tree
2185 tree tmpl_types)
2186 {
2187 tree new_spec_types;
2195 /* Substitute into the rest of the list. */
2196 new_spec_types =
2200 /* Add the default argument for this parameter. */
2203 new_spec_types);
2204 }
2206 /* DECL is an explicit specialization. Replicate default arguments
2207 from the template it specializes. (That way, code like:
2209 template <class T> void f(T = 3);
2210 template <> void f(double);
2211 void g () { f (); }
2213 works, as required.) An alternative approach would be to look up
2214 the correct default arguments at the call-site, but this approach
2215 is consistent with how implicit instantiations are handled. */
2217 static void
2219 {
2220 tree tmpl;
2221 tree spec_types;
2222 tree tmpl_types;
2223 tree new_spec_types;
2224 tree old_type;
2225 tree new_type;
2226 tree t;
2231 /* See if there's anything we need to do. */
2244 {
2245 /* Remove the this pointer, but remember the object's type for
2246 CV quals. */
2252 {
2253 /* DECL may contain more parameters than TMPL due to the extra
2254 in-charge parameter in constructors and destructors. */
2257 }
2259 {
2262 }
2263 }
2265 /* Compute the merged default arguments. */
2266 new_spec_types =
2269 /* Compute the new FUNCTION_TYPE. */
2271 {
2275 new_spec_types);
2278 /* Put the in-charge parameter back. */
2281 new_spec_types);
2285 new_spec_types);
2286 }
2287 else
2289 new_spec_types);
2299 }
2301 /* Return the number of template headers we expect to see for a definition
2302 or specialization of CTYPE or one of its non-template members. */
2304 int
2306 {
2310 {
2311 /* You're supposed to have one `template <...>' for every
2312 template class, but you don't need one for a full
2313 specialization. For example:
2315 template <class T> struct S{};
2316 template <> struct S<int> { void f(); };
2317 void S<int>::f () {}
2319 is correct; there shouldn't be a `template <>' for the
2320 definition of `S<int>::f'. */
2322 /* If CTYPE does not have template information of any
2323 kind, then it is not a template, nor is it nested
2324 within a template. */
2332 }
2335 }
2337 /* Do a simple sanity check on the template headers that precede the
2338 variable declaration DECL. */
2340 void
2342 {
2347 {
2350 "variable templates only available with "
2353 // Namespace-scope variable templates should have a template header.
2355 }
2357 {
2364 "members of an explicitly specialized class are defined "
2366 }
2367 }
2369 /* Check to see if the function just declared, as indicated in
2370 DECLARATOR, and in DECL, is a specialization of a function
2371 template. We may also discover that the declaration is an explicit
2372 instantiation at this point.
2374 Returns DECL, or an equivalent declaration that should be used
2375 instead if all goes well. Issues an error message if something is
2376 amiss. Returns error_mark_node if the error is not easily
2377 recoverable.
2379 FLAGS is a bitmask consisting of the following flags:
2381 2: The function has a definition.
2382 4: The function is a friend.
2384 The TEMPLATE_COUNT is the number of references to qualifying
2385 template classes that appeared in the name of the function. For
2386 example, in
2388 template <class T> struct S { void f(); };
2389 void S<int>::f();
2391 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2392 classes are not counted in the TEMPLATE_COUNT, so that in
2394 template <class T> struct S {};
2395 template <> struct S<int> { void f(); }
2396 template <> void S<int>::f();
2398 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2399 invalid; there should be no template <>.)
2401 If the function is a specialization, it is marked as such via
2402 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2403 is set up correctly, and it is added to the list of specializations
2404 for that template. */
2406 tree
2408 tree decl,
2411 {
2419 tmpl_spec_kind tsk;
2422 {
2425 else
2427 }
2428 else
2432 {
2435 {
2438 }
2440 {
2442 /* This could be something like:
2444 template <class T> void f(T);
2445 class S { friend void f<>(int); } */
2447 else
2448 {
2449 /* This case handles bogus declarations like template <>
2450 template <class T> void f<int>(); */
2453 declarator);
2455 }
2456 }
2460 /* The error has already been reported in
2461 check_specialization_scope. */
2467 /* Fall through. */
2480 decl);
2483 else
2487 /* Fall through. */
2490 /* In cases like template<> constexpr bool v = true;
2491 We'll give an error in check_template_variable. */
2497 else
2503 {
2504 /* This case handles bogus declarations like template <>
2505 template <class T> void f<int>(); */
2509 declarator);
2511 {
2512 /* Partial specialization of variable template. */
2516 }
2520 else
2524 ok:;
2525 }
2528 /* This is a specialization of a member template, without
2529 specialization the containing class. Something like:
2531 template <class T> struct S {
2532 template <class U> void f (U);
2533 };
2534 template <> template <class U> void S<int>::f(U) {}
2536 That's a specialization -- but of the entire template. */
2542 }
2545 /* This doesn't apply to variable templates. */
2548 {
2552 {
2556 }
2557 }
2560 {
2565 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2567 {
2568 tree fns;
2573 else
2574 {
2575 /* If there is no class context, the explicit instantiation
2576 must be at namespace scope. */
2579 /* Find the namespace binding, using the declaration
2580 context. */
2584 {
2587 }
2588 else
2589 {
2595 }
2596 }
2599 }
2605 {
2607 /* A specialization in class scope. This is invalid,
2608 but the error will already have been flagged by
2609 check_specialization_scope. */
2611 else
2612 {
2613 /* It's not valid to write an explicit instantiation in
2614 class scope, e.g.:
2616 class C { template void f(); }
2618 This case is caught by the parser. However, on
2619 something like:
2621 template class C { void f(); };
2623 (which is invalid) we can get here. The error will be
2624 issued later. */
2625 ;
2626 }
2629 }
2632 {
2633 // We'll match variable templates in start_decl.
2637 /* Find the list of functions in ctype that have the same
2638 name as the declared function. */
2644 {
2649 {
2650 /* From [temp.expl.spec]:
2652 If such an explicit specialization for the member
2653 of a class template names an implicitly-declared
2654 special member function (clause _special_), the
2655 program is ill-formed.
2657 Similar language is found in [temp.explicit]. */
2660 }
2663 }
2666 {
2670 }
2671 else
2672 {
2674 tree ovl;
2676 /* For a type-conversion operator, we cannot do a
2677 name-based lookup. We might be looking for `operator
2678 int' which will be a specialization of `operator T'.
2679 So, we find *all* the conversion operators, and then
2680 select from them. */
2688 {
2690 /* There are no more conversion functions. */
2693 /* Glue all these conversion functions together
2694 with those we already have. */
2697 }
2698 }
2701 {
2704 }
2705 else
2707 }
2709 /* Figure out what exactly is being specialized at this point.
2710 Note that for an explicit instantiation, even one for a
2711 member function, we cannot tell apriori whether the
2712 instantiation is for a member template, or just a member
2713 function of a template class. Even if a member template is
2714 being instantiated, the member template arguments may be
2715 elided if they can be deduced from the rest of the
2716 declaration. */
2719 member_specialization,
2720 template_count,
2721 tsk);
2724 /* We couldn't figure out what this declaration was
2725 specializing. */
2727 else
2728 {
2732 {
2733 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2734 is done by do_decl_instantiation later. */
2740 {
2741 /* If TMPL is not the most general template (for
2742 example, if TMPL is a friend template that is
2743 injected into namespace scope), then there will
2744 be too many levels of TARGS. Remove some of them
2745 here. */
2747 tree new_targs;
2754 }
2757 }
2759 /* If we thought that the DECL was a member function, but it
2760 turns out to be specializing a static member function,
2761 make DECL a static member function as well. */
2767 /* If this is a specialization of a member template of a
2768 template class, we want to return the TEMPLATE_DECL, not
2769 the specialization of it. */
2771 {
2776 {
2777 tree parm;
2781 /* We want to use the argument list specified in the
2782 definition, not in the original declaration. */
2787 }
2790 }
2792 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2798 /* Inherit default function arguments from the template
2799 DECL is specializing. */
2803 /* This specialization has the same protection as the
2804 template it specializes. */
2808 /* 7.1.1-1 [dcl.stc]
2810 A storage-class-specifier shall not be specified in an
2811 explicit specialization...
2813 The parser rejects these, so unless action is taken here,
2814 explicit function specializations will always appear with
2815 global linkage.
2817 The action recommended by the C++ CWG in response to C++
2818 defect report 605 is to make the storage class and linkage
2819 of the explicit specialization match the templated function:
2821 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2822 */
2824 {
2828 /* This specialization has the same linkage and visibility as
2829 the function template it specializes. */
2832 {
2835 }
2838 {
2841 }
2842 }
2844 /* If DECL is a friend declaration, declared using an
2845 unqualified name, the namespace associated with DECL may
2846 have been set incorrectly. For example, in:
2848 template <typename T> void f(T);
2849 namespace N {
2850 struct S { friend void f<int>(int); }
2851 }
2853 we will have set the DECL_CONTEXT for the friend
2854 declaration to N, rather than to the global namespace. */
2859 /* This is not really a declaration of a specialization.
2860 It's just the name of an instantiation. But, it's not
2861 a request for an instantiation, either. */
2864 /* A specialization is not necessarily COMDAT. */
2870 /* Register this specialization so that we can find it
2871 again. */
2874 /* A 'structor should already have clones. */
2880 }
2881 }
2884 }
2886 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2887 parameters. These are represented in the same format used for
2888 DECL_TEMPLATE_PARMS. */
2890 int
2892 {
2893 const_tree p1;
2894 const_tree p2;
2902 {
2914 {
2918 /* If either of the template parameters are invalid, assume
2919 they match for the sake of error recovery. */
2932 }
2933 }
2936 /* One set of parameters has more parameters lists than the
2937 other. */
2941 }
2943 /* Determine whether PARM is a parameter pack. */
2945 bool
2947 {
2948 /* Determine if we have a non-type template parameter pack. */
2955 /* If this is a list of template parameters, we could get a
2956 TYPE_DECL or a TEMPLATE_DECL. */
2960 /* Otherwise it must be a type template parameter. */
2964 }
2966 /* Determine if T is a function parameter pack. */
2968 bool
2970 {
2974 }
2976 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2977 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2979 tree
2981 {
2988 }
2990 /* Return true iff the function parameter PARAM_DECL was expanded
2991 from the function parameter pack PACK. */
2993 bool
2995 {
3000 /* The parameter pack and its pack arguments have the same
3001 DECL_PARM_INDEX. */
3003 }
3005 /* Determine whether ARGS describes a variadic template args list,
3006 i.e., one that is terminated by a template argument pack. */
3008 static bool
3010 {
3012 tree last_parm;
3026 }
3028 /* Generate a new name for the parameter pack name NAME (an
3029 IDENTIFIER_NODE) that incorporates its */
3031 static tree
3033 {
3034 /* Munge the name to include the parameter index. */
3035 #define NUMBUF_LEN 128
3049 }
3051 /* Return true if T is a primary function, class or alias template
3052 instantiation. */
3054 bool
3056 {
3070 }
3072 /* Return true if PARM is a template template parameter. */
3074 bool
3076 {
3078 }
3080 /* Return true iff PARM is a DECL representing a type template
3081 parameter. */
3083 bool
3085 {
3090 }
3092 /* Return the template parameters of T if T is a
3093 primary template instantiation, NULL otherwise. */
3095 tree
3097 {
3102 parms = INNERMOST_TEMPLATE_PARMS
3106 }
3108 /* Return the template parameters of the LEVELth level from the full list
3109 of template parameters PARMS. */
3111 tree
3113 {
3114 tree p;
3125 }
3127 /* Returns the template arguments of T if T is a template instantiation,
3128 NULL otherwise. */
3130 tree
3132 {
3140 }
3142 /* Return the argument pack elements of T if T is a template argument pack,
3143 NULL otherwise. */
3145 tree
3147 {
3153 }
3155 /* Structure used to track the progress of find_parameter_packs_r. */
3156 struct find_parameter_pack_data
3157 {
3158 /* TREE_LIST that will contain all of the parameter packs found by
3159 the traversal. */
3162 /* Set of AST nodes that have been visited by the traversal. */
3164 };
3166 /* Identifies all of the argument packs that occur in a template
3167 argument and appends them to the TREE_LIST inside DATA, which is a
3168 find_parameter_pack_data structure. This is a subroutine of
3169 make_pack_expansion and uses_parameter_packs. */
3170 static tree
3172 {
3178 /* Handle type aliases/typedefs. */
3180 {
3187 }
3189 /* Identify whether this is a parameter pack or not. */
3191 {
3207 {
3208 /* We don't want to walk into the type of a PARM_DECL,
3209 because we don't want to see the type parameter pack. */
3212 }
3215 /* Look through a lambda capture proxy to the field pack. */
3218 {
3224 }
3226 {
3228 find_parameter_packs_r,
3231 }
3238 /* Not a parameter pack. */
3240 }
3243 {
3244 /* Add this parameter pack to the list. */
3246 }
3252 /* This switch statement will return immediately if we don't find a
3253 parameter pack. */
3255 {
3260 /* Check the template itself. */
3263 /* Check the template arguments. */
3279 /* Fall through. */
3321 }
3324 }
3326 /* Determines if the expression or type T uses any parameter packs. */
3327 bool
3329 {
3337 }
3339 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3340 representation a base-class initializer into a parameter pack
3341 expansion. If all goes well, the resulting node will be an
3342 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3343 respectively. */
3344 tree
3346 {
3347 tree result;
3356 {
3357 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3358 class initializer. In this case, the TREE_PURPOSE will be a
3359 _TYPE node (representing the base class expansion we're
3360 initializing) and the TREE_VALUE will be a TREE_LIST
3361 containing the initialization arguments.
3363 The resulting expansion looks somewhat different from most
3364 expansions. Rather than returning just one _EXPANSION, we
3365 return a TREE_LIST whose TREE_PURPOSE is a
3366 TYPE_PACK_EXPANSION containing the bases that will be
3367 initialized. The TREE_VALUE will be identical to the
3368 original TREE_VALUE, which is a list of arguments that will
3369 be passed to each base. We do not introduce any new pack
3370 expansion nodes into the TREE_VALUE (although it is possible
3371 that some already exist), because the TREE_PURPOSE and
3372 TREE_VALUE all need to be expanded together with the same
3373 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3374 resulting TREE_PURPOSE will mention the parameter packs in
3375 both the bases and the arguments to the bases. */
3376 tree purpose;
3377 tree value;
3380 /* Determine which parameter packs will be used by the base
3381 class expansion. */
3388 {
3392 }
3395 {
3396 /* Collect the sets of parameter packs used in each of the
3397 initialization arguments. */
3399 {
3400 /* Determine which parameter packs will be expanded in this
3401 argument. */
3404 }
3405 }
3409 /* Create the pack expansion type for the base type. */
3414 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3415 they will rarely be compared to anything. */
3419 }
3424 /* Build the PACK_EXPANSION_* node. */
3425 result = for_types
3430 {
3431 /* Propagate type and const-expression information. */
3434 }
3435 else
3436 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3437 they will rarely be compared to anything. */
3440 /* Determine which parameter packs will be expanded. */
3446 /* Make sure we found some parameter packs. */
3448 {
3451 else
3454 }
3460 }
3462 /* Checks T for any "bare" parameter packs, which have not yet been
3463 expanded, and issues an error if any are found. This operation can
3464 only be done on full expressions or types (e.g., an expression
3465 statement, "if" condition, etc.), because we could have expressions like:
3467 foo(f(g(h(args)))...)
3469 where "args" is a parameter pack. check_for_bare_parameter_packs
3470 should not be called for the subexpressions args, h(args),
3471 g(h(args)), or f(g(h(args))), because we would produce erroneous
3472 error messages.
3474 Returns TRUE and emits an error if there were bare parameter packs,
3475 returns FALSE otherwise. */
3476 bool
3478 {
3494 {
3497 {
3506 else
3511 else
3515 }
3518 }
3521 }
3523 /* Expand any parameter packs that occur in the template arguments in
3524 ARGS. */
3525 tree
3527 {
3533 /* First, determine if we need to expand anything, and the number of
3534 slots we'll need. */
3536 {
3541 {
3545 else
3547 }
3548 else
3549 {
3551 num_result_args++;
3552 }
3553 }
3555 /* If no expansion is necessary, we're done. */
3559 /* Expand arguments. */
3562 non_default_args_count =
3565 {
3568 {
3575 }
3576 else
3577 {
3580 }
3581 }
3585 }
3587 /* Checks if DECL shadows a template parameter.
3589 [temp.local]: A template-parameter shall not be redeclared within its
3590 scope (including nested scopes).
3592 Emits an error and returns TRUE if the DECL shadows a parameter,
3593 returns FALSE otherwise. */
3595 bool
3597 {
3598 tree olddecl;
3600 /* If we're not in a template, we can't possibly shadow a template
3601 parameter. */
3605 /* Figure out what we're shadowing. */
3610 /* If there's no previous binding for this name, we're not shadowing
3611 anything, let alone a template parameter. */
3615 /* If we're not shadowing a template parameter, we're done. Note
3616 that OLDDECL might be an OVERLOAD (or perhaps even an
3617 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3618 node. */
3622 /* We check for decl != olddecl to avoid bogus errors for using a
3623 name inside a class. We check TPFI to avoid duplicate errors for
3624 inline member templates. */
3630 /* Don't complain about the injected class name, as we've already
3631 complained about the class itself. */
3638 }
3640 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3641 ORIG_LEVEL, DECL, and TYPE. */
3643 static tree
3647 tree decl,
3648 tree type)
3649 {
3660 }
3662 /* Find the canonical type parameter for the given template type
3663 parameter. Returns the canonical type parameter, which may be TYPE
3664 if no such parameter existed. */
3666 static tree
3668 {
3669 tree list;
3683 else
3684 {
3689 }
3690 }
3692 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3693 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3694 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3695 new one is created. */
3697 static tree
3699 tsubst_flags_t complain)
3700 {
3705 {
3724 /* Template template parameters need this. */
3729 }
3732 }
3734 /* Process information from new template parameter PARM and append it
3735 to the LIST being built. This new parameter is a non-type
3736 parameter iff IS_NON_TYPE is true. This new parameter is a
3737 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3738 is in PARM_LOC. */
3740 tree
3743 {
3745 tree defval;
3752 {
3756 {
3760 else
3762 }
3765 }
3768 {
3774 {
3775 /* [temp.param]
3777 The top-level cv-qualifiers on the template-parameter are
3778 ignored when determining its type. */
3783 && !is_parameter_pack
3784 /* If we're in a nested template parameter list, the template
3785 template parameter could be a parameter pack. */
3787 {
3788 /* This template parameter is not a parameter pack, but it
3789 should be. Complain about "bare" parameter packs. */
3792 /* Recover by calling this a parameter pack. */
3794 }
3795 }
3797 /* A template parameter is not modifiable. */
3806 processing_template_decl,
3811 }
3812 else
3813 {
3814 tree t;
3818 {
3820 /* This is for distinguishing between real templates and template
3821 template parameters */
3825 }
3826 else
3827 {
3829 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3832 }
3839 processing_template_decl,
3843 }
3849 }
3851 /* The end of a template parameter list has been reached. Process the
3852 tree list into a parameter vector, converting each parameter into a more
3853 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3854 as PARM_DECLs. */
3856 tree
3858 {
3863 current_template_parms
3868 {
3872 }
3877 }
3879 /* end_template_decl is called after a template declaration is seen. */
3881 void
3883 {
3889 /* This matches the pushlevel in begin_template_parm_list. */
3894 }
3896 /* Takes a TREE_LIST representing a template parameter and convert it
3897 into an argument suitable to be passed to the type substitution
3898 functions. Note that If the TREE_LIST contains an error_mark
3899 node, the returned argument is error_mark_node. */
3901 static tree
3903 {
3916 {
3920 {
3921 /* Turn this argument into a TYPE_ARGUMENT_PACK
3922 with a single element, which expands T. */
3924 #ifdef ENABLE_CHECKING
3925 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3927 #endif
3932 }
3933 }
3934 else
3935 {
3939 {
3940 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3941 with a single element, which expands T. */
3944 #ifdef ENABLE_CHECKING
3945 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3947 #endif
3954 }
3955 else
3957 }
3959 }
3961 /* Given a set of template parameters, return them as a set of template
3962 arguments. The template parameters are represented as a TREE_VEC, in
3963 the form documented in cp-tree.h for template arguments. */
3965 static tree
3967 {
3968 tree header;
3973 /* If there is only one level of template parameters, we do not
3974 create a TREE_VEC of TREE_VECs. Instead, we return a single
3975 TREE_VEC containing the arguments. */
3980 {
3988 #ifdef ENABLE_CHECKING
3990 #endif
3994 else
3996 }
3999 /* This can happen for template parms of a template template
4000 parameter, e.g:
4002 template<template<class T, class U> class TT> struct S;
4004 Consider the level of the parms of TT; T and U both have
4005 level 2; TT has no template parm of level 1. So in this case
4006 the first element of full_template_args is NULL_TREE. If we
4007 leave it like this TMPL_ARGS_DEPTH on args returns 1 instead
4008 of 2. This will make tsubst wrongly consider that T and U
4009 have level 1. Instead, let's create a dummy vector as the
4010 first element of full_template_args so that TMPL_ARGS_DEPTH
4011 returns the correct depth for args. */
4014 }
4016 /* Within the declaration of a template, return the currently active
4017 template parameters as an argument TREE_VEC. */
4019 static tree
4021 {
4023 }
4025 /* Update the declared TYPE by doing any lookups which were thought to be
4026 dependent, but are not now that we know the SCOPE of the declarator. */
4028 tree
4030 {
4041 /* Don't bother building up the args in this case. */
4043 {
4044 /* tsubst in the args corresponding to the template parameters,
4045 including auto if present. Most things will be unchanged, but
4046 make_typename_type and tsubst_qualified_id will resolve
4047 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4050 tree pushed;
4052 {
4056 }
4061 }
4067 {
4070 else
4072 }
4074 }
4076 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4077 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
4078 a member template. Used by push_template_decl below. */
4080 static tree
4082 {
4090 }
4092 struct template_parm_data
4093 {
4094 /* The level of the template parameters we are currently
4095 processing. */
4098 /* The index of the specialization argument we are currently
4099 processing. */
4102 /* An array whose size is the number of template parameters. The
4103 elements are nonzero if the parameter has been used in any one
4104 of the arguments processed so far. */
4107 /* An array whose size is the number of template arguments. The
4108 elements are nonzero if the argument makes use of template
4109 parameters of this level. */
4111 };
4113 /* Subroutine of push_template_decl used to see if each template
4114 parameter in a partial specialization is used in the explicit
4115 argument list. If T is of the LEVEL given in DATA (which is
4116 treated as a template_parm_data*), then DATA->PARMS is marked
4117 appropriately. */
4119 static int
4121 {
4129 {
4132 }
4134 /* Return zero so that for_each_template_parm will continue the
4135 traversal of the tree; we want to mark *every* template parm. */
4137 }
4139 /* Process the partial specialization DECL. */
4141 static tree
4143 {
4150 tree inner_parms;
4151 tree inst;
4164 /* We check that each of the template parameters given in the
4165 partial specialization is used in the argument list to the
4166 specialization. For example:
4168 template <class T> struct S;
4169 template <class T> struct S<T*>;
4171 The second declaration is OK because `T*' uses the template
4172 parameter T, whereas
4174 template <class T> struct S<int>;
4176 is no good. Even trickier is:
4178 template <class T>
4179 struct S1
4180 {
4181 template <class U>
4182 struct S2;
4183 template <class U>
4184 struct S2<T>;
4185 };
4187 The S2<T> declaration is actually invalid; it is a
4188 full-specialization. Of course,
4190 template <class U>
4191 struct S2<T (*)(U)>;
4193 or some such would have been OK. */
4201 {
4206 NULL,
4208 }
4211 {
4212 /* One of the template parms was not used in a deduced context in the
4213 specialization. */
4215 {
4219 }
4223 }
4228 /* [temp.class.spec]
4230 The argument list of the specialization shall not be identical to
4231 the implicit argument list of the primary template. */
4232 tree main_args
4238 /* A partial specialization that replaces multiple parameters of the
4239 primary template with a pack expansion is less specialized for those
4240 parameters. */
4242 {
4244 "primary template because it replaces multiple parameters "
4248 }
4250 /* [temp.class.spec]
4252 A partially specialized non-type argument expression shall not
4253 involve template parameters of the partial specialization except
4254 when the argument expression is a simple identifier.
4256 The type of a template parameter corresponding to a specialized
4257 non-type argument shall not be dependent on a parameter of the
4258 specialization.
4260 Also, we verify that pack expansions only occur at the
4261 end of the argument list. */
4265 {
4272 {
4273 /* Extract the arguments from the argument pack. We'll be
4274 iterating over these in the following loop. */
4277 }
4280 {
4282 /* Get the Jth argument in the parameter pack. */
4286 {
4287 /* Pack expansions must come at the end of the
4288 argument list. */
4291 {
4295 else
4298 }
4299 }
4302 /* We only care about the pattern. */
4308 /* This next two lines are the `argument expression is not just a
4309 simple identifier' condition and also the `specialized
4310 non-type argument' bit. */
4314 {
4318 arg);
4319 else
4320 {
4321 /* Look at the corresponding template parameter,
4322 marking which template parameters its type depends
4323 upon. */
4327 {
4328 /* We haven't yet initialized TPD2. Do so now. */
4330 /* The number of parameters here is the number in the
4331 main template, which, as checked in the assertion
4332 above, is NARGS. */
4336 }
4338 /* Mark the template parameters. But this time, we're
4339 looking for the template parameters of the main
4340 template, not in the specialization. */
4347 NULL,
4351 {
4352 /* The type depended on some template parameters.
4353 If they are fully specialized in the
4354 specialization, that's OK. */
4363 "type %qT of template argument %qE depends "
4365 "type %qT of template argument %qE depends "
4367 type,
4368 arg);
4369 }
4370 }
4371 }
4372 }
4373 }
4375 /* We should only get here once. */
4394 {
4400 {
4403 {
4407 "partial specialization of %qD after instantiation "
4409 }
4410 }
4411 }
4414 }
4416 /* PARM is a template parameter of some form; return the corresponding
4417 TEMPLATE_PARM_INDEX. */
4419 static tree
4421 {
4434 }
4436 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4437 parameter packs used by the template parameter PARM. */
4439 static void
4441 {
4442 /* A type parm can't refer to another parm. */
4446 {
4450 }
4457 }
4459 /* PARM is a template parameter pack. Return any parameter packs used in
4460 its type or the type of any of its template parameters. If there are
4461 any such packs, it will be instantiated into a fixed template parameter
4462 list by partial instantiation rather than be fully deduced. */
4464 tree
4466 {
4467 /* This can only be true in a member template. */
4470 /* This can only be true for a parameter pack. */
4473 /* A type parm can't refer to another parm. */
4486 }
4488 /* Check that a template declaration's use of default arguments and
4489 parameter packs is not invalid. Here, PARMS are the template
4490 parameters. IS_PRIMARY is true if DECL is the thing declared by
4491 a primary template. IS_PARTIAL is true if DECL is a partial
4492 specialization.
4494 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4495 declaration (but not a definition); 1 indicates a declaration, 2
4496 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4497 emitted for extraneous default arguments.
4499 Returns TRUE if there were no errors found, FALSE otherwise. */
4501 bool
4504 {
4507 tree parm_level;
4510 /* [temp.param]
4512 A default template-argument shall not be specified in a
4513 function template declaration or a function template definition, nor
4514 in the template-parameter-list of the definition of a member of a
4515 class template. */
4519 /* You can't have a function template declaration in a local
4520 scope, nor you can you define a member of a class template in a
4521 local scope. */
4529 /* A lambda doesn't have an explicit declaration; don't complain
4530 about the parms of the enclosing class. */
4537 /* If this is either a friend defined in the scope of the class
4538 or a member function. */
4544 /* And, if it was a member function, it really was defined in
4545 the scope of the class. */
4548 /* We already checked these parameters when the template was
4549 declared, so there's no need to do it again now. This function
4550 was defined in class scope, but we're processing its body now
4551 that the class is complete. */
4554 /* Core issue 226 (C++0x only): the following only applies to class
4555 templates. */
4558 {
4559 /* [temp.param]
4561 If a template-parameter has a default template-argument, all
4562 subsequent template-parameters shall have a default
4563 template-argument supplied. */
4565 {
4572 {
4582 {
4584 /* For better subsequent error-recovery, we indicate that
4585 there should have been a default argument. */
4588 }
4590 && !is_friend_decl
4591 /* Don't complain about an enclosing partial
4592 specialization. */
4597 /* A fixed parameter pack will be partially
4598 instantiated into a fixed length list. */
4600 {
4601 /* A primary class template can only have one
4602 parameter pack, at the end of the template
4603 parameter list. */
4611 }
4612 }
4613 }
4614 }
4617 || is_partial
4618 || !is_primary
4620 /* For an ordinary class template, default template arguments are
4621 allowed at the innermost level, e.g.:
4622 template <class T = int>
4623 struct S {};
4624 but, in a partial specialization, they're not allowed even
4625 there, as we have in [temp.class.spec]:
4627 The template parameter list of a specialization shall not
4628 contain default template argument values.
4630 So, for a partial specialization, or for a function template
4631 (in C++98/C++03), we look at all of them. */
4632 ;
4633 else
4634 /* But, for a primary class template that is not a partial
4635 specialization we look at all template parameters except the
4636 innermost ones. */
4639 /* Figure out what error message to issue. */
4652 else
4656 /* If we're inside a class definition, there's no need to
4657 examine the parameters to the class itself. On the one
4658 hand, they will be checked when the class is defined, and,
4659 on the other, default arguments are valid in things like:
4660 template <class T = double>
4661 struct S { template <class U> void f(U); };
4662 Here the default argument for `S' has no bearing on the
4663 declaration of `f'. */
4665 else
4666 /* Check everything. */
4672 {
4679 {
4684 {
4686 {
4693 }
4695 /* Clear out the default argument so that we are not
4696 confused later. */
4698 }
4699 }
4701 /* At this point, if we're still interested in issuing messages,
4702 they must apply to classes surrounding the object declared. */
4706 }
4709 }
4711 /* Worker for push_template_decl_real, called via
4712 for_each_template_parm. DATA is really an int, indicating the
4713 level of the parameters we are interested in. If T is a template
4714 parameter of that level, return nonzero. */
4716 static int
4718 {
4724 else
4727 }
4729 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4730 parameters given by current_template_args, or reuses a
4731 previously existing one, if appropriate. Returns the DECL, or an
4732 equivalent one, if it is replaced via a call to duplicate_decls.
4734 If IS_FRIEND is true, DECL is a friend declaration. */
4736 tree
4738 {
4739 tree tmpl;
4740 tree args;
4741 tree info;
4742 tree ctx;
4746 /* True if the template is a member template, in the sense of
4747 [temp.mem]. */
4753 /* See if this is a partial specialization. */
4766 /* For a friend, we want the context of the friend function, not
4767 the type of which it is a friend. */
4771 /* In the case of a virtual function, we want the class in which
4772 it is defined. */
4774 else
4775 /* Otherwise, if we're currently defining some class, the DECL
4776 is assumed to be a member of the class. */
4785 /* See if this is a primary template. */
4788 /* A friend template that specifies a class context, i.e.
4789 template <typename T> friend void A<T>::f();
4790 is not primary. */
4795 else
4799 {
4804 {
4807 }
4809 {
4811 {
4814 }
4816 {
4817 /* [temp.mem]
4819 A destructor shall not be a member template. */
4822 }
4829 {
4830 /* [basic.stc.dynamic.allocation]
4832 An allocation function can be a function
4833 template. ... Template allocation functions shall
4834 have two or more parameters. */
4837 }
4838 }
4844 /* alias-declaration */
4848 else
4849 {
4852 }
4853 }
4855 /* Check to see that the rules regarding the use of default
4856 arguments are not being violated. */
4860 /* Ensure that there are no parameter packs in the type of this
4861 declaration that have not been expanded. */
4863 {
4864 /* Check each of the arguments individually to see if there are
4865 any bare parameter packs. */
4871 {
4874 {
4875 /* This is a PARM_DECL that contains unexpanded parameter
4876 packs. We have already complained about this in the
4877 check_for_bare_parameter_packs call, so just replace
4878 these types with ERROR_MARK_NODE. */
4881 }
4885 }
4887 /* Check for bare parameter packs in the return type and the
4888 exception specifiers. */
4890 /* Errors were already issued, set return type to int
4891 as the frontend doesn't expect error_mark_node as
4892 the return type. */
4896 }
4901 {
4904 }
4917 {
4922 /* If DECL is a TYPE_DECL for a class-template, then there won't
4923 be DECL_LANG_SPECIFIC. The information equivalent to
4924 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4928 {
4929 /* Since a template declaration already existed for this
4930 class-type, we must be redeclaring it here. Make sure
4931 that the redeclaration is valid. */
4933 current_template_parms);
4934 /* We don't need to create a new TEMPLATE_DECL; just use the
4935 one we already had. */
4937 }
4938 else
4939 {
4941 member_template_p);
4946 {
4947 /* A specialization of a member template of a template
4948 class. */
4952 }
4953 }
4954 }
4955 else
4956 {
4962 {
4965 }
4973 {
4974 tree new_tmpl;
4976 /* The declaration is a specialization of a member
4977 template, declared outside the class. Therefore, the
4978 innermost template arguments will be NULL, so we
4979 replace them with the arguments determined by the
4980 earlier call to check_explicit_specialization. */
4983 new_tmpl
4985 member_template_p);
4995 args,
4998 }
5000 /* Make sure the template headers we got make sense. */
5005 {
5010 }
5011 else
5013 {
5018 {
5022 else
5026 /* Avoid crash in import_export_decl. */
5029 }
5034 /* Can happen in erroneous input. */
5036 else
5038 }
5040 /* Check that the parms are used in the appropriate qualifying scopes
5041 in the declarator. */
5045 {
5051 /* Avoid crash in import_export_decl. */
5054 }
5055 }
5060 /* Push template declarations for global functions and types. Note
5061 that we do not try to push a global template friend declared in a
5062 template class; such a thing may well depend on the template
5063 parameters of the class. */
5066 {
5071 /* Hide template friend classes that haven't been declared yet. */
5073 {
5076 }
5077 }
5080 {
5086 {
5089 /* It is a conversion operator. See if the type converted to
5090 depends on innermost template operands. */
5093 depth))
5095 }
5097 /* Give template template parms a DECL_CONTEXT of the template
5098 for which they are a parameter. */
5101 {
5105 }
5111 }
5113 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5114 back to its most general template. If TMPL is a specialization,
5115 ARGS may only have the innermost set of arguments. Add the missing
5116 argument levels if necessary. */
5124 else
5125 {
5130 }
5133 && !is_friend
5136 /* Set DECL_COMDAT on template instantiations; if we force
5137 them to be emitted by explicit instantiation or -frepo,
5138 mark_needed will tell cgraph to do the right thing. */
5142 }
5144 tree
5146 {
5148 }
5150 /* FN is an inheriting constructor that inherits from the constructor
5151 template INHERITED; turn FN into a constructor template with a matching
5152 template header. */
5154 tree
5156 {
5157 tree inner_parms
5160 tree parms
5171 }
5173 /* Called when a class template TYPE is redeclared with the indicated
5174 template PARMS, e.g.:
5176 template <class T> struct S;
5177 template <class T> struct S {}; */
5179 bool
5181 {
5182 tree tmpl;
5183 tree tmpl_parms;
5187 {
5190 }
5194 /* The type is nested in some template class. Nothing to worry
5195 about here; there are no new template parameters for the nested
5196 type. */
5200 {
5202 tmpl);
5204 }
5210 {
5220 }
5223 {
5224 tree tmpl_parm;
5225 tree parm;
5226 tree tmpl_default;
5227 tree parm_default;
5241 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5242 TEMPLATE_DECL. */
5252 {
5256 }
5259 {
5260 /* We have in [temp.param]:
5262 A template-parameter may not be given default arguments
5263 by two different declarations in the same scope. */
5268 }
5271 /* Update the previous template parameters (which are the ones
5272 that will really count) with the new default value. */
5275 /* Update the new parameters, too; they'll be used as the
5276 parameters for any members. */
5278 }
5281 }
5283 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5284 to be used when the caller has already checked
5285 (processing_template_decl
5286 && !instantiation_dependent_expression_p (expr)
5287 && potential_constant_expression (expr))
5288 and cleared processing_template_decl. */
5290 tree
5292 {
5295 complain,
5299 }
5301 /* Simplify EXPR if it is a non-dependent expression. Returns the
5302 (possibly simplified) expression. */
5304 tree
5306 {
5310 /* If we're in a template, but EXPR isn't value dependent, simplify
5311 it. We're supposed to treat:
5313 template <typename T> void f(T[1 + 1]);
5314 template <typename T> void f(T[2]);
5316 as two declarations of the same function, for example. */
5320 {
5321 processing_template_decl_sentinel s;
5323 }
5325 }
5327 tree
5329 {
5331 }
5333 /* True iff T is a specialization of a variable template. */
5335 bool
5337 {
5342 }
5344 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5345 template declaration, or a TYPE_DECL for an alias declaration. */
5347 bool
5349 {
5357 }
5359 /* Return TRUE iff T is a specialization of an alias template. */
5361 bool
5363 {
5364 /* It's an alias template specialization if it's an alias and its
5365 TYPE_NAME is a specialization of a primary template. */
5367 {
5371 {
5374 }
5375 }
5377 }
5379 /* An alias template is complex from a SFINAE perspective if a template-id
5380 using that alias can be ill-formed when the expansion is not, as with
5381 the void_t template. We determine this by checking whether the
5382 expansion for the alias template uses all its template parameters. */
5384 struct uses_all_template_parms_data
5385 {
5388 };
5390 static int
5392 {
5400 }
5402 static bool
5404 {
5419 }
5421 /* Return TRUE iff T is a specialization of a complex alias template with
5422 dependent template-arguments. */
5424 bool
5426 {
5429 && (any_dependent_template_arguments_p
5431 }
5433 /* Return the number of innermost template parameters in TMPL. */
5435 static int
5437 {
5440 }
5442 /* Return either TMPL or another template that it is equivalent to under DR
5443 1286: An alias that just changes the name of a template is equivalent to
5444 the other template. */
5446 static tree
5448 {
5451 {
5454 {
5459 {
5460 tree alias_args = INNERMOST_TEMPLATE_ARGS
5464 /* The alias type is equivalent to the pattern of the
5465 underlying template, so strip the alias. */
5468 }
5469 }
5471 }
5473 }
5475 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5476 must be a function or a pointer-to-function type, as specified
5477 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5478 and check that the resulting function has external linkage. */
5480 static tree
5482 tsubst_flags_t complain)
5483 {
5486 linkage_kind linkage;
5498 /* [temp.arg.nontype]/1
5500 A template-argument for a non-type, non-template template-parameter
5501 shall be one of:
5502 [...]
5503 -- the address of an object or function with external [C++11: or
5504 internal] linkage. */
5507 {
5509 {
5515 else
5518 }
5520 }
5524 {
5526 {
5531 else
5535 }
5537 }
5540 }
5542 /* Subroutine of convert_nontype_argument.
5543 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5544 Emit an error otherwise. */
5546 static bool
5548 tsubst_flags_t complain)
5549 {
5560 {
5564 }
5566 }
5568 /* Returns TRUE iff the address of OP is value-dependent.
5570 14.6.2.4 [temp.dep.temp]:
5571 A non-integral non-type template-argument is dependent if its type is
5572 dependent or it has either of the following forms
5573 qualified-id
5574 & qualified-id
5575 and contains a nested-name-specifier which specifies a class-name that
5576 names a dependent type.
5578 We generalize this to just say that the address of a member of a
5579 dependent class is value-dependent; the above doesn't cover the
5580 address of a static data member named with an unqualified-id. */
5582 static bool
5584 {
5585 /* We could use get_inner_reference here, but there's no need;
5586 this is only relevant for template non-type arguments, which
5587 can only be expressed as &id-expression. */
5589 {
5593 }
5596 }
5598 /* The next set of functions are used for providing helpful explanatory
5599 diagnostics for failed overload resolution. Their messages should be
5600 indented by two spaces for consistency with the messages in
5601 call.c */
5603 static int
5605 {
5607 }
5609 static int
5611 {
5616 }
5618 static int
5620 {
5622 }
5624 static int
5626 {
5632 }
5634 static int
5636 {
5640 }
5642 static int
5644 {
5647 " template parameter %qD is not a parameter pack, but "
5651 }
5653 static int
5655 {
5658 " template argument %qE does not match "
5662 }
5664 static int
5666 {
5670 }
5672 static int
5674 {
5680 }
5682 static int
5684 {
5686 {
5691 else
5693 " deduced conflicting values for non-type parameter "
5695 }
5697 }
5699 static int
5701 {
5704 " variable-sized array type %qT is not "
5706 arg);
5708 }
5710 static int
5712 {
5716 arg);
5718 }
5720 static int
5722 {
5724 {
5730 else
5735 }
5737 }
5739 static int
5741 {
5743 }
5745 static int
5748 {
5750 }
5752 static int
5755 {
5761 }
5763 static int
5766 {
5769 {
5777 }
5779 }
5781 static int
5783 {
5786 " template parameters of a template template argument are "
5789 }
5791 static int
5793 {
5799 }
5801 static int
5803 {
5808 }
5810 static int
5812 {
5816 arg);
5818 }
5820 /* Attempt to convert the non-type template parameter EXPR to the
5821 indicated TYPE. If the conversion is successful, return the
5822 converted value. If the conversion is unsuccessful, return
5823 NULL_TREE if we issued an error message, or error_mark_node if we
5824 did not. We issue error messages for out-and-out bad template
5825 parameters, but not simply because the conversion failed, since we
5826 might be just trying to do argument deduction. Both TYPE and EXPR
5827 must be non-dependent.
5829 The conversion follows the special rules described in
5830 [temp.arg.nontype], and it is much more strict than an implicit
5831 conversion.
5833 This function is called twice for each template argument (see
5834 lookup_template_class for a more accurate description of this
5835 problem). This means that we need to handle expressions which
5836 are not valid in a C++ source, but can be created from the
5837 first call (for instance, casts to perform conversions). These
5838 hacks can go away after we fix the double coercion problem. */
5840 static tree
5842 {
5843 tree expr_type;
5845 /* Detect immediately string literals as invalid non-type argument.
5846 This special-case is not needed for correctness (we would easily
5847 catch this later), but only to provide better diagnostic for this
5848 common user mistake. As suggested by DR 100, we do not mention
5849 linkage issues in the diagnostic as this is not the point. */
5850 /* FIXME we're making this OK. */
5852 {
5858 }
5860 /* Add the ADDR_EXPR now for the benefit of
5861 value_dependent_expression_p. */
5864 {
5868 }
5870 /* If we are in a template, EXPR may be non-dependent, but still
5871 have a syntactic, rather than semantic, form. For example, EXPR
5872 might be a SCOPE_REF, rather than the VAR_DECL to which the
5873 SCOPE_REF refers. Preserving the qualifying scope is necessary
5874 so that access checking can be performed when the template is
5875 instantiated -- but here we need the resolved form so that we can
5876 convert the argument. */
5882 && processing_template_decl
5891 else
5894 /* If the argument is non-dependent, perform any conversions in
5895 non-dependent context as well. */
5900 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5901 to a non-type argument of "nullptr". */
5905 /* In C++11, integral or enumeration non-type template arguments can be
5906 arbitrary constant expressions. Pointer and pointer to
5907 member arguments can be general constant expressions that evaluate
5908 to a null value, but otherwise still need to be of a specific form. */
5910 {
5912 /* A PTRMEM_CST is already constant, and a valid template
5913 argument for a parameter of pointer to member type, we just want
5914 to leave it in that form rather than lower it to a
5919 {
5924 }
5925 }
5927 /* HACK: Due to double coercion, we can get a
5928 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5929 which is the tree that we built on the first call (see
5930 below when coercing to reference to object or to reference to
5931 function). We just strip everything and get to the arg.
5932 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5933 for examples. */
5935 {
5941 {
5942 /* ??? Maybe we could use convert_from_reference here, but we
5943 would need to relax its constraints because the NOP_EXPR
5944 could actually change the type to something more cv-qualified,
5945 and this is not folded by convert_from_reference. */
5950 && (same_type_ignoring_top_level_qualifiers_p
5953 {
5956 }
5957 }
5958 }
5960 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5961 parameter is a pointer to object, through decay and
5962 qualification conversion. Let's strip everything. */
5964 {
5969 {
5970 /* Skip the ADDR_EXPR only if it is part of the decay for
5971 an array. Otherwise, it is part of the original argument
5972 in the source code. */
5977 }
5978 }
5980 /* [temp.arg.nontype]/5, bullet 1
5982 For a non-type template-parameter of integral or enumeration type,
5983 integral promotions (_conv.prom_) and integral conversions
5984 (_conv.integral_) are applied. */
5986 {
5995 /* Notice that there are constant expressions like '4 % 0' which
5996 do not fold into integer constants. */
5998 {
6000 {
6011 /* else cxx_constant_value complained but gave us
6012 a real constant, so go ahead. */
6014 }
6015 else
6017 }
6019 /* Avoid typedef problems. */
6022 }
6023 /* [temp.arg.nontype]/5, bullet 2
6025 For a non-type template-parameter of type pointer to object,
6026 qualification conversions (_conv.qual_) and the array-to-pointer
6027 conversion (_conv.array_) are applied. */
6029 {
6030 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6032 A template-argument for a non-type, non-template template-parameter
6033 shall be one of: [...]
6035 -- the name of a non-type template-parameter;
6036 -- the address of an object or function with external linkage, [...]
6037 expressed as "& id-expression" where the & is optional if the name
6038 refers to a function or array, or if the corresponding
6039 template-parameter is a reference.
6041 Here, we do not care about functions, as they are invalid anyway
6042 for a parameter of type pointer-to-object. */
6045 /* Non-type template parameters are OK. */
6046 ;
6051 {
6053 {
6056 "because %qD is a variable, not the address of "
6059 }
6061 {
6067 }
6068 /* Other values, like integer constants, might be valid
6069 non-type arguments of some other type. */
6071 }
6072 else
6073 {
6074 tree decl;
6079 {
6084 }
6086 {
6092 }
6094 {
6099 }
6100 }
6109 }
6110 /* [temp.arg.nontype]/5, bullet 3
6112 For a non-type template-parameter of type reference to object, no
6113 conversions apply. The type referred to by the reference may be more
6114 cv-qualified than the (otherwise identical) type of the
6115 template-argument. The template-parameter is bound directly to the
6116 template-argument, which must be an lvalue. */
6118 {
6120 expr_type))
6124 {
6129 }
6132 {
6137 }
6139 /* [temp.arg.nontype]/1
6141 A template-argument for a non-type, non-template template-parameter
6142 shall be one of: [...]
6144 -- the address of an object or function with external linkage. */
6147 {
6150 {
6153 "because a reference variable does not have a constant "
6156 }
6157 }
6160 {
6166 }
6169 {
6175 }
6178 }
6179 /* [temp.arg.nontype]/5, bullet 4
6181 For a non-type template-parameter of type pointer to function, only
6182 the function-to-pointer conversion (_conv.func_) is applied. If the
6183 template-argument represents a set of overloaded functions (or a
6184 pointer to such), the matching function is selected from the set
6185 (_over.over_). */
6187 {
6188 /* If the argument is a template-id, we might not have enough
6189 context information to decay the pointer. */
6191 {
6195 }
6198 /* Null pointer values are OK in C++11. */
6204 }
6205 /* [temp.arg.nontype]/5, bullet 5
6207 For a non-type template-parameter of type reference to function, no
6208 conversions apply. If the template-argument represents a set of
6209 overloaded functions, the matching function is selected from the set
6210 (_over.over_). */
6212 {
6214 {
6216 {
6221 }
6223 }
6230 }
6231 /* [temp.arg.nontype]/5, bullet 6
6233 For a non-type template-parameter of type pointer to member function,
6234 no conversions apply. If the template-argument represents a set of
6235 overloaded member functions, the matching member function is selected
6236 from the set (_over.over_). */
6238 {
6243 /* [temp.arg.nontype] bullet 1 says the pointer to member
6244 expression must be a pointer-to-member constant. */
6248 /* There is no way to disable standard conversions in
6249 resolve_address_of_overloaded_function (called by
6250 instantiate_type). It is possible that the call succeeded by
6251 converting &B::I to &D::I (where B is a base of D), so we need
6252 to reject this conversion here.
6254 Actually, even if there was a way to disable standard conversions,
6255 it would still be better to reject them here so that we can
6256 provide a superior diagnostic. */
6258 {
6260 {
6264 /* If we are just one standard conversion off, explain. */
6268 }
6270 }
6271 }
6272 /* [temp.arg.nontype]/5, bullet 7
6274 For a non-type template-parameter of type pointer to data member,
6275 qualification conversions (_conv.qual_) are applied. */
6277 {
6278 /* [temp.arg.nontype] bullet 1 says the pointer to member
6279 expression must be a pointer-to-member constant. */
6286 }
6288 {
6290 {
6295 }
6297 }
6298 /* A template non-type parameter must be one of the above. */
6299 else
6302 /* Sanity check: did we actually convert the argument to the
6303 right type? */
6307 }
6309 /* Subroutine of coerce_template_template_parms, which returns 1 if
6310 PARM_PARM and ARG_PARM match using the rule for the template
6311 parameters of template template parameters. Both PARM and ARG are
6312 template parameters; the rest of the arguments are the same as for
6313 coerce_template_template_parms.
6314 */
6315 static int
6317 tree arg,
6318 tsubst_flags_t complain,
6319 tree in_decl,
6320 tree outer_args)
6321 {
6330 {
6332 /* We encounter instantiations of templates like
6333 template <template <template <class> class> class TT>
6334 class C; */
6335 {
6342 }
6343 /* Fall through. */
6348 /* Argument is a parameter pack but parameter is not. */
6353 /* The tsubst call is used to handle cases such as
6355 template <int> class C {};
6356 template <class T, template <T> class TT> class D {};
6357 D<int, C> d;
6359 i.e. the parameter list of TT depends on earlier parameters. */
6361 && !same_type_p
6368 /* Argument is a parameter pack but parameter is not. */
6375 }
6378 }
6381 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6382 template template parameters. Both PARM_PARMS and ARG_PARMS are
6383 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6384 or PARM_DECL.
6386 Consider the example:
6387 template <class T> class A;
6388 template<template <class U> class TT> class B;
6390 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6391 the parameters to A, and OUTER_ARGS contains A. */
6393 static int
6395 tree arg_parms,
6396 tsubst_flags_t complain,
6397 tree in_decl,
6398 tree outer_args)
6399 {
6410 /* Determine whether we have a parameter pack at the end of the
6411 template template parameter's template parameter list. */
6413 {
6420 {
6434 }
6435 }
6441 /* Check all of the template parameters except the parameter pack at
6442 the end (if any). */
6444 {
6453 outer_args))
6456 }
6459 {
6460 /* Check each of the template parameters in the template
6461 argument against the template parameter pack at the end of
6462 the template template parameter. */
6469 {
6476 outer_args))
6478 }
6479 }
6482 }
6484 /* Verifies that the deduced template arguments (in TARGS) for the
6485 template template parameters (in TPARMS) represent valid bindings,
6486 by comparing the template parameter list of each template argument
6487 to the template parameter list of its corresponding template
6488 template parameter, in accordance with DR150. This
6489 routine can only be called after all template arguments have been
6490 deduced. It will return TRUE if all of the template template
6491 parameter bindings are okay, FALSE otherwise. */
6492 bool
6494 {
6498 /* We're dealing with template parms in this process. */
6504 {
6509 {
6514 {
6515 /* Look inside the argument pack. */
6518 }
6521 {
6525 /* Extract the next argument from the argument
6526 pack. */
6530 /* Look at the pattern of the pack expansion. */
6533 /* Extract the template parameters from the template
6534 argument. */
6540 /* Verify that we can coerce the template template
6541 parameters from the template argument to the template
6542 parameter. This requires an exact match. */
6544 && !coerce_template_template_parms
6546 targ_parms,
6547 tf_none,
6548 tparm,
6549 targs))
6550 {
6553 }
6554 }
6555 }
6556 }
6558 out:
6562 }
6564 /* Since type attributes aren't mangled, we need to strip them from
6565 template type arguments. */
6567 static tree
6569 {
6570 tree mv;
6577 {
6582 }
6584 }
6586 /* Convert the indicated template ARG as necessary to match the
6587 indicated template PARM. Returns the converted ARG, or
6588 error_mark_node if the conversion was unsuccessful. Error and
6589 warning messages are issued under control of COMPLAIN. This
6590 conversion is for the Ith parameter in the parameter list. ARGS is
6591 the full set of template arguments deduced so far. */
6593 static tree
6595 tree arg,
6596 tree args,
6597 tsubst_flags_t complain,
6599 tree in_decl)
6600 {
6601 tree orig_arg;
6602 tree val;
6610 {
6611 /* The template argument was the name of some
6612 member function. That's usually
6613 invalid, but static members are OK. In any
6614 case, grab the underlying fields/functions
6615 and issue an error later if required. */
6618 }
6626 /* When determining whether an argument pack expansion is a template,
6627 look at the pattern. */
6631 /* Deal with an injected-class-name used as a template template arg. */
6633 {
6636 {
6646 }
6647 }
6649 is_tmpl_type =
6665 {
6667 {
6671 }
6674 "to refer to a type member of a template parameter, "
6679 typename_type,
6680 complain);
6683 }
6685 {
6687 {
6689 {
6701 else
6704 }
6705 }
6707 }
6709 {
6711 {
6718 else
6721 }
6723 }
6726 {
6728 {
6732 /* The number of argument required is not known yet.
6733 Just accept it for now. */
6735 else
6736 {
6738 tree argparm;
6740 /* Strip alias templates that are equivalent to another
6741 template. */
6747 args))
6748 {
6751 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6752 TEMPLATE_DECL. */
6754 {
6759 }
6760 }
6761 else
6762 {
6764 {
6771 }
6774 }
6775 }
6776 }
6777 else
6779 /* We only form one instance of each template specialization.
6780 Therefore, if we use a non-canonical variant (i.e., a
6781 typedef), any future messages referring to the type will use
6782 the typedef, which is confusing if those future uses do not
6783 themselves also use the typedef. */
6786 }
6787 else
6788 {
6795 {
6798 else
6799 {
6800 /* Not sure if this is reachable, but it doesn't hurt
6801 to be robust. */
6804 }
6805 }
6808 /* We used to call digest_init here. However, digest_init
6809 will report errors, which we don't want when complain
6810 is zero. More importantly, digest_init will try too
6811 hard to convert things: for example, `0' should not be
6812 converted to pointer type at this point according to
6813 the standard. Accepting this is not merely an
6814 extension, since deciding whether or not these
6815 conversions can occur is part of determining which
6816 function template to call, or whether a given explicit
6817 argument specification is valid. */
6819 else
6828 {
6829 /* Strip typedefs from the SCOPE_REF. */
6832 complain);
6835 }
6836 }
6839 }
6841 /* Coerces the remaining template arguments in INNER_ARGS (from
6842 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6843 Returns the coerced argument pack. PARM_IDX is the position of this
6844 parameter in the template parameter list. ARGS is the original
6845 template argument list. */
6846 static tree
6849 tree args,
6850 tree inner_args,
6852 tree new_args,
6854 tree in_decl,
6855 tsubst_flags_t complain)
6856 {
6859 tree packed_args;
6860 tree argument_pack;
6867 {
6868 /* When the template parameter is a non-type template parameter pack
6869 or template template parameter pack whose type or template
6870 parameters use parameter packs, we know exactly how many arguments
6871 we are looking for. Build a vector of the instantiated decls for
6872 these template parameters in PACKED_PARMS. */
6873 /* We can't use make_pack_expansion here because it would interpret a
6874 _DECL as a use rather than a declaration. */
6888 /* If we're doing a partial instantiation of a member template,
6889 verify that all of the types used for the non-type
6890 template parameter pack are, in fact, valid for non-type
6891 template parameters. */
6894 {
6897 {
6901 }
6902 /* We don't know how many args we have yet, just
6903 use the unconverted ones for now. */
6905 }
6908 }
6909 else
6912 /* Convert the remaining arguments, which will be a part of the
6913 parameter pack "parm". */
6915 {
6921 {
6922 /* Once we've packed as many args as we have types, stop. */
6926 /* We don't know how many args we have yet, just
6927 use the unconverted ones for now. */
6929 else
6931 }
6934 {
6937 }
6938 else
6941 in_decl);
6945 }
6949 {
6954 }
6959 else
6960 {
6965 }
6968 #ifdef ENABLE_CHECKING
6971 #endif
6973 }
6975 /* Returns the number of pack expansions in the template argument vector
6976 ARGS. */
6978 static int
6980 {
6985 {
6989 }
6991 }
6993 /* Convert all template arguments to their appropriate types, and
6994 return a vector containing the innermost resulting template
6995 arguments. If any error occurs, return error_mark_node. Error and
6996 warning messages are issued under control of COMPLAIN.
6998 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6999 for arguments not specified in ARGS. Otherwise, if
7000 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7001 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7002 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7003 ARGS. */
7005 static tree
7007 tree args,
7008 tree in_decl,
7009 tsubst_flags_t complain,
7012 {
7014 tree orig_inner_args;
7015 tree inner_args;
7016 tree new_args;
7017 tree new_inner_args;
7021 /* When used as a boolean value, indicates whether this is a
7022 variadic template parameter list. Since it's an int, we can also
7023 subtract it from nparms to get the number of non-variadic
7024 parameters. */
7029 /* Likewise for parameters with default arguments. */
7037 /* Determine if there are any parameter packs or default arguments. */
7039 {
7047 }
7050 /* If there are no parameters that follow a parameter pack, we need to
7051 expand any argument packs so that we can deduce a parameter pack from
7052 some non-packed args followed by an argument pack, as in variadic85.C.
7053 If there are such parameters, we need to leave argument packs intact
7054 so the arguments are assigned properly. This can happen when dealing
7055 with a nested class inside a partial specialization of a class
7056 template, as in variadic92.C, or when deducing a template parameter pack
7057 from a sub-declarator, as in variadic114.C. */
7061 /* Count any pack expansion args. */
7067 && require_all_args
7068 && !variadic_args_p
7069 && (!use_default_args
7072 {
7074 {
7076 {
7080 }
7081 else
7087 }
7090 }
7091 /* We can't pass a pack expansion to a non-pack parameter of an alias
7092 template (DR 1430). */
7094 && variadic_args_p
7096 {
7098 {
7100 {
7106 {
7111 }
7112 }
7114 found:;
7115 }
7117 }
7119 /* We need to evaluate the template arguments, even though this
7120 template-id may be nested within a "sizeof". */
7129 {
7130 tree arg;
7131 tree parm;
7133 /* Get the Ith template parameter. */
7137 {
7140 }
7142 /* Calculate the next argument. */
7145 else
7150 {
7151 /* Some arguments will be placed in the
7152 template parameter pack PARM. */
7159 {
7160 /* We don't know how many args we have yet, just use the
7161 unconverted (and still packed) ones for now. */
7165 }
7169 /* Store this argument. */
7171 {
7172 lost++;
7173 /* We are done with all of the arguments. */
7175 }
7176 else
7177 {
7180 }
7183 }
7185 {
7187 {
7188 /* "If every valid specialization of a variadic template
7189 requires an empty template parameter pack, the template is
7190 ill-formed, no diagnostic required." So check that the
7191 pattern works with this parameter. */
7196 in_decl);
7198 {
7202 }
7204 /* Recover from missing typename. */
7208 /* We don't know how many args we have yet, just
7209 use the unconverted ones for now. */
7213 }
7214 }
7216 {
7217 /* There must be a default arg in this case. */
7220 /* The position of the first default template argument,
7221 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7222 Record that. */
7226 }
7227 else
7231 {
7234 }
7236 /* This only occurs if there was an error in the template
7237 parameter list itself (which we would already have
7238 reported) that we are trying to recover from, e.g., a class
7239 template with a parameter list such as
7240 template<typename..., typename>. */
7242 else
7248 lost++;
7250 }
7255 {
7257 {
7262 }
7264 }
7269 #ifdef ENABLE_CHECKING
7273 #endif
7276 }
7278 /* Like coerce_template_parms. If PARMS represents all template
7279 parameters levels, this function returns a vector of vectors
7280 representing all the resulting argument levels. Note that in this
7281 case, only the innermost arguments are coerced because the
7282 outermost ones are supposed to have been coerced already.
7284 Otherwise, if PARMS represents only (the innermost) vector of
7285 parameters, this function returns a vector containing just the
7286 innermost resulting arguments. */
7288 static tree
7290 tree args,
7291 tree in_decl,
7292 tsubst_flags_t complain,
7295 {
7298 tree coerced_args;
7301 {
7303 tree level;
7309 {
7310 tree l;
7314 require_all_args,
7315 use_default_args);
7316 else
7323 }
7324 }
7325 else
7328 require_all_args,
7329 use_default_args);
7331 }
7333 /* Returns 1 if template args OT and NT are equivalent. */
7335 static int
7337 {
7344 /* For member templates */
7353 {
7370 }
7372 {
7373 /* We get here probably because we are in the middle of substituting
7374 into the pattern of a pack expansion. In that case the
7375 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7376 interested in. So we want to use the initial pack argument for
7377 the comparison. */
7382 }
7384 {
7387 /* Don't treat an alias template specialization with dependent
7388 arguments as equivalent to its underlying type when used as a
7389 template argument; we need them to be distinct so that we
7390 substitute into the specialization arguments at instantiation
7391 time. And aliases can't be equivalent without being ==, so
7392 we don't need to look any deeper. */
7395 else
7397 }
7400 else
7401 {
7402 /* Try to treat a template non-type argument that has been converted
7403 to the parameter type as equivalent to one that hasn't yet. */
7416 }
7417 }
7419 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7420 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7421 NEWARG_PTR with the offending arguments if they are non-NULL. */
7423 static int
7426 {
7439 {
7444 {
7450 }
7451 }
7453 }
7455 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7456 of template arguments. Returns 0 otherwise. */
7458 int
7460 {
7462 }
7464 static void
7466 {
7476 /* We are called both from instantiate_decl, where we've already had a
7477 tinst_level pushed, and instantiate_template, where we haven't.
7478 Compensate. */
7489 else
7498 }
7501 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7502 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7503 documentation for TEMPLATE_ID_EXPR. */
7505 tree
7507 {
7508 tree type;
7516 {
7519 }
7522 {
7524 unknown_type_node,
7526 arglist);
7528 }
7535 }
7537 /* Within the scope of a template class S<T>, the name S gets bound
7538 (in build_self_reference) to a TYPE_DECL for the class, not a
7539 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
7540 or one of its enclosing classes, and that type is a template,
7541 return the associated TEMPLATE_DECL. Otherwise, the original
7542 DECL is returned.
7544 Also handle the case when DECL is a TREE_LIST of ambiguous
7545 injected-class-names from different bases. */
7547 tree
7549 {
7553 /* DR 176: A lookup that finds an injected-class-name (10.2
7554 [class.member.lookup]) can result in an ambiguity in certain cases
7555 (for example, if it is found in more than one base class). If all of
7556 the injected-class-names that are found refer to specializations of
7557 the same class template, and if the name is followed by a
7558 template-argument-list, the reference refers to the class template
7559 itself and not a specialization thereof, and is not ambiguous. */
7561 {
7564 {
7570 }
7573 else
7575 }
7581 }
7583 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
7584 parameters, find the desired type.
7586 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7588 IN_DECL, if non-NULL, is the template declaration we are trying to
7589 instantiate.
7591 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7592 the class we are looking up.
7594 Issue error and warning messages under control of COMPLAIN.
7596 If the template class is really a local class in a template
7597 function, then the FUNCTION_CONTEXT is the function in which it is
7598 being instantiated.
7600 ??? Note that this function is currently called *twice* for each
7601 template-id: the first time from the parser, while creating the
7602 incomplete type (finish_template_type), and the second type during the
7603 real instantiation (instantiate_template_class). This is surely something
7604 that we want to avoid. It also causes some problems with argument
7605 coercion (see convert_nontype_argument for more information on this). */
7607 static tree
7610 {
7612 tree t;
7615 spec_entry elt;
7616 hashval_t hash;
7619 {
7623 else
7624 {
7631 }
7634 }
7636 {
7639 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7640 an implicit typename for the second A. Deal with it. */
7645 {
7648 }
7649 }
7652 {
7655 }
7657 {
7661 }
7663 {
7666 }
7668 /* Issue an error message if we didn't find a template. */
7670 {
7674 }
7677 /* Make sure it's a user visible template, if it was named by
7678 the user. */
7681 {
7683 {
7687 }
7689 }
7693 /* An alias that just changes the name of a template is equivalent to the
7694 other template, so if any of the arguments are pack expansions, strip
7695 the alias to avoid problems with a pack expansion passed to a non-pack
7696 alias template parameter (DR 1430). */
7701 {
7702 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7703 template arguments */
7705 tree parm;
7706 tree arglist2;
7707 tree outer;
7711 /* Consider an example where a template template parameter declared as
7713 template <class T, class U = std::allocator<T> > class TT
7715 The template parameter level of T and U are one level larger than
7716 of TT. To proper process the default argument of U, say when an
7717 instantiation `TT<int>' is seen, we need to build the full
7718 arguments containing {int} as the innermost level. Outer levels,
7719 available when not appearing as default template argument, can be
7720 obtained from the arguments of the enclosing template.
7722 Suppose that TT is later substituted with std::vector. The above
7723 instantiation is `TT<int, std::allocator<T> >' with TT at
7724 level 1, and T at level 2, while the template arguments at level 1
7725 becomes {std::vector} and the inner level 2 is {int}. */
7731 /* This is an argument of the current template, so we haven't set
7732 DECL_CONTEXT yet. */
7739 complain,
7749 }
7750 else
7751 {
7753 tree gen_tmpl;
7754 tree type_decl;
7762 /* An error occurred while building the template TEMPL, and a
7763 diagnostic has most certainly been emitted for that
7764 already. Let's propagate that error. */
7773 {
7774 /* We've been given an incomplete set of template arguments.
7775 For example, given:
7777 template <class T> struct S1 {
7778 template <class U> struct S2 {};
7779 template <class U> struct S2<U*> {};
7780 };
7782 we will be called with an ARGLIST of `U*', but the
7783 TEMPLATE will be `template <class T> template
7784 <class U> struct S1<T>::S2'. We must fill in the missing
7785 arguments. */
7786 arglist
7788 arglist);
7790 }
7792 /* Now we should have enough arguments. */
7795 /* From here on, we're only interested in the most general
7796 template. */
7798 /* Calculate the BOUND_ARGS. These will be the args that are
7799 actually tsubst'd into the definition to create the
7800 instantiation. */
7802 {
7803 /* We have multiple levels of arguments to coerce, at once. */
7813 {
7814 tree a;
7818 complain,
7821 else
7822 /* Outer levels should have already been coerced. */
7825 /* Don't process further if one of the levels fails. */
7827 {
7828 /* Restore the ARGLIST to its full size. */
7831 }
7835 /* We temporarily reduce the length of the ARGLIST so
7836 that coerce_template_parms will see only the arguments
7837 corresponding to the template parameters it is
7838 examining. */
7840 }
7842 /* Restore the ARGLIST to its full size. */
7846 }
7847 else
7848 arglist
7851 gen_tmpl,
7852 complain,
7857 /* We were unable to bind the arguments. */
7860 /* In the scope of a template class, explicit references to the
7861 template class refer to the type of the template, not any
7862 instantiation of it. For example, in:
7864 template <class T> class C { void f(C<T>); }
7866 the `C<T>' is just the same as `C'. Outside of the
7867 class, however, such a reference is an instantiation. */
7871 /* comp_template_args is expensive, check it last. */
7873 arglist))
7876 /* If we already have this specialization, return it. */
7887 /* If the deduced arguments are invalid, then the binding
7888 failed. */
7892 complain))
7899 {
7904 }
7914 /* Create the type. */
7916 {
7917 /* The user referred to a specialization of an alias
7918 template represented by GEN_TMPL.
7920 [temp.alias]/2 says:
7922 When a template-id refers to the specialization of an
7923 alias template, it is equivalent to the associated
7924 type obtained by substitution of its
7925 template-arguments for the template-parameters in the
7926 type-id of the alias template. */
7929 /* Note that the call above (by indirectly calling
7930 register_specialization in tsubst_decl) registers the
7931 TYPE_DECL representing the specialization of the alias
7932 template. So next time someone substitutes ARGLIST for
7933 the template parms into the alias template (GEN_TMPL),
7934 she'll get that TYPE_DECL back. */
7938 }
7940 {
7942 {
7951 }
7952 else
7953 {
7954 /* We don't want to call start_enum for this type, since
7955 the values for the enumeration constants may involve
7956 template parameters. And, no one should be interested
7957 in the enumeration constants for such a type. */
7960 }
7964 }
7966 {
7973 /* A local class. Make sure the decl gets registered properly. */
7978 /* This instantiation is another name for the primary
7979 template type. Set the TYPE_CANONICAL field
7980 appropriately. */
7983 /* Some of the template arguments require structural
7984 equality testing, so this template class requires
7985 structural equality testing. */
7987 }
7988 else
7991 /* If we called start_enum or pushtag above, this information
7992 will already be set up. */
7994 {
8001 }
8002 else
8006 {
8012 {
8015 }
8016 }
8020 {
8023 {
8026 else
8030 }
8031 }
8033 /* Let's consider the explicit specialization of a member
8034 of a class template specialization that is implicitly instantiated,
8035 e.g.:
8036 template<class T>
8037 struct S
8038 {
8039 template<class U> struct M {}; //#0
8040 };
8042 template<>
8043 template<>
8044 struct S<int>::M<char> //#1
8045 {
8046 int i;
8047 };
8048 [temp.expl.spec]/4 says this is valid.
8050 In this case, when we write:
8051 S<int>::M<char> m;
8053 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8054 the one of #0.
8056 When we encounter #1, we want to store the partial instantiation
8057 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8059 For all cases other than this "explicit specialization of member of a
8060 class template", we just want to store the most general template into
8061 the CLASSTYPE_TI_TEMPLATE of M.
8063 This case of "explicit specialization of member of a class template"
8064 only happens when:
8065 1/ the enclosing class is an instantiation of, and therefore not
8066 the same as, the context of the most general template, and
8067 2/ we aren't looking at the partial instantiation itself, i.e.
8068 the innermost arguments are not the same as the innermost parms of
8069 the most general template.
8071 So it's only when 1/ and 2/ happens that we want to use the partial
8072 instantiation of the member template in lieu of its most general
8073 template. */
8077 /* the enclosing class must be an instantiation... */
8080 {
8081 tree partial_inst_args;
8084 partial_inst_args =
8090 use_partial_inst_tmpl =
8091 /*...and we must not be looking at the partial instantiation
8092 itself. */
8094 partial_inst_args);
8095 }
8098 /* This case is easy; there are no member templates involved. */
8100 else
8101 {
8102 /* This is a full instantiation of a member template. Find
8103 the partial instantiation of which this is an instance. */
8105 /* Temporarily reduce by one the number of levels in the ARGLIST
8106 so as to avoid comparing the last set of arguments. */
8110 /* FOUND is either a proper class type, or an alias
8111 template specialization. In the later case, it's a
8112 TYPE_DECL, resulting from the substituting of arguments
8113 for parameters in the TYPE_DECL of the alias template
8114 done earlier. So be careful while getting the template
8115 of FOUND. */
8119 }
8129 /* Note this use of the partial instantiation so we can check it
8130 later in maybe_process_partial_specialization. */
8137 /* Now that the type has been registered on the instantiations
8138 list, we set up the enumerators. Because the enumeration
8139 constants may involve the enumeration type itself, we make
8140 sure to register the type first, and then create the
8141 constants. That way, doing tsubst_expr for the enumeration
8142 constants won't result in recursive calls here; we'll find
8143 the instantiation and exit above. */
8147 /* If the type makes use of template parameters, the
8148 code that generates debugging information will crash. */
8151 /* Possibly limit visibility based on template args. */
8158 }
8159 }
8161 /* Wrapper for lookup_template_class_1. */
8163 tree
8166 {
8167 tree ret;
8173 }
8175 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST.
8176 The type of the expression is the unknown_type_node since the
8177 template-id could refer to an explicit or partial specialization. */
8179 tree
8181 {
8184 }
8186 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8188 tree
8190 {
8203 }
8204 \f
8205 struct pair_fn_data
8206 {
8207 tree_fn_t fn;
8209 /* True when we should also visit template parameters that occur in
8210 non-deduced contexts. */
8213 };
8215 /* Called from for_each_template_parm via walk_tree. */
8217 static tree
8219 {
8232 {
8236 /* Fall through. */
8259 /* Since we're not going to walk subtrees, we have to do this
8260 explicitly here. */
8264 /* Fall through. */
8267 /* Check the return type. */
8272 /* Check the parameter types. Since default arguments are not
8273 instantiated until they are needed, the TYPE_ARG_TYPES may
8274 contain expressions that involve template parameters. But,
8275 no-one should be looking at them yet. And, once they're
8276 instantiated, they don't contain template parameters, so
8277 there's no point in looking at them then, either. */
8278 {
8279 tree parm;
8286 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8287 want walk_tree walking into them itself. */
8289 }
8307 /* Fall through. */
8323 /* Record template parameters such as `T' inside `TT<T>'. */
8327 /* Fall through. */
8339 /* A template template parameter is encountered. */
8345 /* Already substituted template template parameter */
8368 /* If there's no type, then this thing must be some expression
8369 involving template parameters. */
8391 }
8393 /* We didn't find any template parameters we liked. */
8395 }
8397 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8398 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8399 call FN with the parameter and the DATA.
8400 If FN returns nonzero, the iteration is terminated, and
8401 for_each_template_parm returns 1. Otherwise, the iteration
8402 continues. If FN never returns a nonzero value, the value
8403 returned by for_each_template_parm is 0. If FN is NULL, it is
8404 considered to be the function which always returns 1.
8406 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8407 parameters that occur in non-deduced contexts. When false, only
8408 visits those template parameters that can be deduced. */
8410 static int
8414 {
8418 /* Set up. */
8423 /* Walk the tree. (Conceptually, we would like to walk without
8424 duplicates, but for_each_template_parm_r recursively calls
8425 for_each_template_parm, so we would need to reorganize a fair
8426 bit to use walk_tree_without_duplicates, so we keep our own
8427 visited list.) */
8430 else
8433 for_each_template_parm_r,
8437 /* Clean up. */
8439 {
8442 }
8445 }
8447 /* Returns true if T depends on any template parameter. */
8449 int
8451 {
8481 else
8482 {
8485 }
8490 }
8492 /* Returns true iff current_function_decl is an incompletely instantiated
8493 template. Useful instead of processing_template_decl because the latter
8494 is set to 0 during instantiate_non_dependent_expr. */
8496 bool
8498 {
8507 }
8509 /* Returns true if T depends on any template parameter with level LEVEL. */
8511 int
8513 {
8516 }
8518 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8519 ill-formed translation unit, i.e. a variable or function that isn't
8520 usable in a constant expression. */
8524 {
8528 }
8530 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8531 neglectable and instantiated from within an erroneous instantiation. */
8533 static bool
8535 {
8546 }
8554 /* We're starting to instantiate D; record the template instantiation context
8555 for diagnostics and to restore it later. */
8557 bool
8559 {
8561 }
8563 /* We're starting to instantiate D; record the template instantiation context
8564 at LOC for diagnostics and to restore it later. */
8566 bool
8568 {
8572 {
8574 "template instantiation depth exceeds maximum of %d"
8576 max_tinst_depth);
8578 }
8580 /* If the current instantiation caused problems, don't let it instantiate
8581 anything else. Do allow deduction substitution and decls usable in
8582 constant expressions. */
8599 }
8601 /* We're done instantiating this template; return to the instantiation
8602 context. */
8604 void
8606 {
8607 /* Restore the filename and line number stashed away when we started
8608 this instantiation. */
8612 }
8614 /* We're instantiating a deferred template; restore the template
8615 instantiation context in which the instantiation was requested, which
8616 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
8618 static tree
8620 {
8632 }
8634 /* Returns the TINST_LEVEL which gives the original instantiation
8635 context. */
8639 {
8645 }
8647 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8648 vector of template arguments, as for tsubst.
8650 Returns an appropriate tsubst'd friend declaration. */
8652 static tree
8654 {
8655 tree new_friend;
8660 /* This was a friend declared with an explicit template
8661 argument list, e.g.:
8663 friend void f<>(T);
8665 to indicate that f was a template instantiation, not a new
8666 function declaration. Now, we have to figure out what
8667 instantiation of what template. */
8668 {
8670 tree new_args;
8671 tree tmpl;
8674 /* Friend functions are looked up in the containing namespace scope.
8675 We must enter that scope, to avoid finding member functions of the
8676 current class with same name. */
8691 tsk_none);
8693 }
8697 /* The NEW_FRIEND will look like an instantiation, to the
8698 compiler, but is not an instantiation from the point of view of
8699 the language. For example, we might have had:
8701 template <class T> struct S {
8702 template <class U> friend void f(T, U);
8703 };
8705 Then, in S<int>, template <class U> void f(int, U) is not an
8706 instantiation of anything. */
8712 {
8716 }
8718 /* The mangled name for the NEW_FRIEND is incorrect. The function
8719 is not a template instantiation and should not be mangled like
8720 one. Therefore, we forget the mangling here; we'll recompute it
8721 later if we need it. */
8723 {
8726 }
8729 {
8730 tree old_decl;
8731 tree new_friend_template_info;
8732 tree new_friend_result_template_info;
8733 tree ns;
8736 /* We must save some information from NEW_FRIEND before calling
8737 duplicate decls since that function will free NEW_FRIEND if
8738 possible. */
8740 new_friend_is_defn =
8745 {
8746 /* This declaration is a `primary' template. */
8749 new_friend_result_template_info
8751 }
8752 else
8755 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8759 /* Inside pushdecl_namespace_level, we will push into the
8760 current namespace. However, the friend function should go
8761 into the namespace of the template. */
8771 {
8772 /* This new friend declaration matched an existing
8773 declaration. For example, given:
8775 template <class T> void f(T);
8776 template <class U> class C {
8777 template <class T> friend void f(T) {}
8778 };
8780 the friend declaration actually provides the definition
8781 of `f', once C has been instantiated for some type. So,
8782 old_decl will be the out-of-class template declaration,
8783 while new_friend is the in-class definition.
8785 But, if `f' was called before this point, the
8786 instantiation of `f' will have DECL_TI_ARGS corresponding
8787 to `T' but not to `U', references to which might appear
8788 in the definition of `f'. Previously, the most general
8789 template for an instantiation of `f' was the out-of-class
8790 version; now it is the in-class version. Therefore, we
8791 run through all specialization of `f', adding to their
8792 DECL_TI_ARGS appropriately. In particular, they need a
8793 new set of outer arguments, corresponding to the
8794 arguments for this class instantiation.
8796 The same situation can arise with something like this:
8798 friend void f(int);
8799 template <class T> class C {
8800 friend void f(T) {}
8801 };
8803 when `C<int>' is instantiated. Now, `f(int)' is defined
8804 in the class. */
8807 /* On the other hand, if the in-class declaration does
8808 *not* provide a definition, then we don't want to alter
8809 existing definitions. We can just leave everything
8810 alone. */
8811 ;
8812 else
8813 {
8817 /* Overwrite whatever template info was there before, if
8818 any, with the new template information pertaining to
8819 the declaration. */
8823 {
8824 /* We should have called reregister_specialization in
8825 duplicate_decls. */
8830 /* Instantiate it if the global has already been used. */
8834 }
8835 else
8836 {
8837 tree t;
8839 /* Indicate that the old function template is a partial
8840 instantiation. */
8848 /* Reassign any specializations already in the hash table
8849 to the new more general template, and add the
8850 additional template args. */
8854 {
8856 spec_entry elt;
8868 register_specialization
8871 }
8873 }
8874 }
8876 /* The information from NEW_FRIEND has been merged into OLD_DECL
8877 by duplicate_decls. */
8879 }
8880 }
8881 else
8882 {
8886 /* In the code
8887 template <class T> class C {
8888 template <class U> friend void C1<U>::f (); // case 1
8889 friend void C2<T>::f (); // case 2
8890 };
8891 we only need to make sure CONTEXT is a complete type for
8892 case 2. To distinguish between the two cases, we note that
8893 CONTEXT of case 1 remains dependent type after tsubst while
8894 this isn't true for case 2. */
8904 {
8906 /* do_friend adds the TEMPLATE_DECL for any member friend
8907 template even if it isn't a member template, i.e.
8908 template <class T> friend A<T>::f();
8909 Look through it in that case. */
8913 /* Check to see that the declaration is really present, and,
8914 possibly obtain an improved declaration. */
8919 }
8920 }
8923 }
8925 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8926 template arguments, as for tsubst.
8928 Returns an appropriate tsubst'd friend type or error_mark_node on
8929 failure. */
8931 static tree
8933 {
8934 tree friend_type;
8935 tree tmpl;
8936 tree context;
8939 {
8942 }
8947 {
8950 else
8952 }
8954 /* Look for a class template declaration. We look for hidden names
8955 because two friend declarations of the same template are the
8956 same. For example, in:
8958 struct A {
8959 template <typename> friend class F;
8960 };
8961 template <typename> struct B {
8962 template <typename> friend class F;
8963 };
8965 both F templates are the same. */
8969 /* But, if we don't find one, it might be because we're in a
8970 situation like this:
8972 template <class T>
8973 struct S {
8974 template <class U>
8975 friend struct S;
8976 };
8978 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8979 for `S<int>', not the TEMPLATE_DECL. */
8981 {
8984 }
8987 {
8988 /* The friend template has already been declared. Just
8989 check to see that the declarations match, and install any new
8990 default parameters. We must tsubst the default parameters,
8991 of course. We only need the innermost template parameters
8992 because that is all that redeclare_class_template will look
8993 at. */
8996 {
8997 tree parms;
8998 location_t saved_input_location;
9007 }
9010 }
9011 else
9012 {
9013 /* The friend template has not already been declared. In this
9014 case, the instantiation of the template class will cause the
9015 injection of this template into the global scope. */
9020 /* The new TMPL is not an instantiation of anything, so we
9021 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9022 the new type because that is supposed to be the corresponding
9023 template decl, i.e., TMPL. */
9030 /* Inject this template into the global scope. */
9032 }
9035 {
9038 else
9040 }
9043 }
9045 /* Returns zero if TYPE cannot be completed later due to circularity.
9046 Otherwise returns one. */
9048 static int
9050 {
9060 else
9062 }
9066 /* Apply any attributes which had to be deferred until instantiation
9067 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9068 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9070 static void
9073 {
9075 tree t;
9080 {
9084 }
9087 {
9091 }
9092 else
9096 {
9101 {
9104 {
9111 {
9118 clauses
9122 else
9124 }
9125 /* If the first attribute argument is an identifier, don't
9126 pass it through tsubst. Attributes like mode, format,
9127 cleanup and several target specific attributes expect it
9128 unmodified. */
9131 {
9132 tree chain
9134 in_decl,
9139 chain);
9140 }
9142 {
9143 /* An attribute pack expansion. */
9145 tree pack = (tsubst_pack_expansion
9149 {
9153 }
9155 }
9156 else
9162 }
9163 else
9165 }
9168 }
9169 }
9171 /* Perform (or defer) access check for typedefs that were referenced
9172 from within the template TMPL code.
9173 This is a subroutine of instantiate_decl and instantiate_class_template.
9174 TMPL is the template to consider and TARGS is the list of arguments of
9175 that template. */
9177 static void
9179 {
9180 location_t saved_location;
9191 {
9203 /* Make access check error messages point to the location
9204 of the use of the typedef. */
9208 tf_warning_or_error);
9209 }
9211 }
9213 static tree
9215 {
9217 tree typedecl;
9218 tree pbinfo;
9219 tree base_list;
9221 tree fn_context;
9230 /* Figure out which template is being instantiated. */
9234 /* Determine what specialization of the original template to
9235 instantiate. */
9238 {
9241 }
9243 {
9244 /* This TYPE is actually an instantiation of a partial
9245 specialization. We replace the innermost set of ARGS with
9246 the arguments appropriate for substitution. For example,
9247 given:
9249 template <class T> struct S {};
9250 template <class T> struct S<T*> {};
9252 and supposing that we are instantiating S<int*>, ARGS will
9253 presently be {int*} -- but we need {int}. */
9256 }
9257 else
9258 {
9261 }
9263 /* If the template we're instantiating is incomplete, then clearly
9264 there's nothing we can do. */
9268 /* If we've recursively instantiated too many templates, stop. */
9272 /* Now we're really doing the instantiation. Mark the type as in
9273 the process of being defined. */
9276 /* We may be in the middle of deferred access check. Disable
9277 it now. */
9284 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9289 else
9290 {
9293 }
9294 /* Use #pragma pack from the template context. */
9300 /* Set the input location to the most specialized template definition.
9301 This is needed if tsubsting causes an error. */
9313 {
9316 /* Adjust visibility for template arguments. */
9318 }
9324 /* We should never instantiate a nested class before its enclosing
9325 class; we need to look up the nested class by name before we can
9326 instantiate it, and that lookup should instantiate the enclosing
9327 class. */
9333 {
9334 tree pbase_binfo;
9335 tree pushed_scope;
9338 /* We must enter the scope containing the type, as that is where
9339 the accessibility of types named in dependent bases are
9340 looked up from. */
9343 /* Substitute into each of the bases to determine the actual
9344 basetypes. */
9346 {
9347 tree base;
9353 {
9354 expanded_bases =
9361 }
9364 {
9366 /* Extract the already-expanded base class. */
9368 else
9369 /* Substitute to figure out the base class. */
9371 NULL_TREE);
9379 }
9380 }
9382 /* The list is now in reverse order; correct that. */
9387 }
9388 /* Now call xref_basetypes to set up all the base-class
9389 information. */
9397 /* Now that our base classes are set up, enter the scope of the
9398 class, so that name lookups into base classes, etc. will work
9399 correctly. This is precisely analogous to what we do in
9400 begin_class_definition when defining an ordinary non-template
9401 class, except we also need to push the enclosing classes. */
9404 /* Now members are processed in the order of declaration. */
9407 {
9411 {
9413 {
9414 /* Build new CLASSTYPE_NESTED_UTDS. */
9416 tree newtag;
9422 /* If the member is a class template, then -- even after
9423 substitution -- there may be dependent types in the
9424 template argument list for the class. We increment
9425 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9426 that function will assume that no types are dependent
9427 when outside of a template. */
9437 {
9441 /* Unfortunately, lookup_template_class sets
9442 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9443 instantiation (i.e., for the type of a member
9444 template class nested within a template class.)
9445 This behavior is required for
9446 maybe_process_partial_specialization to work
9447 correctly, but is not accurate in this case;
9448 the TAG is not an instantiation of anything.
9449 (The corresponding TEMPLATE_DECL is an
9450 instantiation, but the TYPE is not.) */
9453 /* Now, we call pushtag to put this NEWTAG into the scope of
9454 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9455 pushtag calling push_template_decl. We don't have to do
9456 this for enums because it will already have been done in
9457 tsubst_enum. */
9461 }
9462 }
9464 {
9465 /* Build new TYPE_METHODS. */
9466 tree r;
9475 /* Instantiate members marked with attribute used. */
9481 }
9484 /* A closure type for a lambda in a default argument for a
9485 member template. Ignore it; it will be instantiated with
9487 else
9488 {
9489 /* Build new TYPE_FIELDS. */
9491 {
9492 tree condition;
9495 condition =
9505 }
9507 {
9508 tree r;
9512 /* The file and line for this declaration, to
9513 assist in error message reporting. Since we
9514 called push_tinst_level above, we don't need to
9515 restore these. */
9525 {
9526 /* A capture pack became multiple fields. */
9529 }
9532 {
9536 {
9537 /* In [temp.inst]:
9539 [t]he initialization (and any associated
9540 side-effects) of a static data member does
9541 not occur unless the static data member is
9542 itself used in a way that requires the
9543 definition of the static data member to
9544 exist.
9546 Therefore, we do not substitute into the
9547 initialized for the static data member here. */
9548 finish_static_data_member_decl
9554 /* Instantiate members marked with attribute used. */
9557 }
9559 {
9560 /* Determine whether R has a valid type and can be
9561 completed later. If R is invalid, then its type
9562 is replaced by error_mark_node. */
9568 {
9571 }
9572 }
9574 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
9575 such a thing will already have been added to the field
9576 list by tsubst_enum in finish_member_declaration in the
9577 CLASSTYPE_NESTED_UTDS case above. */
9581 {
9584 }
9585 }
9586 }
9587 }
9588 }
9589 else
9590 {
9593 {
9594 /* Build new CLASSTYPE_FRIEND_CLASSES. */
9600 {
9601 /* template <class T> friend class C; */
9604 }
9606 {
9607 /* template <class T> friend class C::D; */
9613 }
9616 {
9617 /* This could be either
9619 friend class T::C;
9621 when dependent_type_p is false or
9623 template <class U> friend class T::C;
9625 otherwise. */
9628 /* Bump processing_template_decl for correct
9629 dependent_type_p calculation. */
9634 }
9637 {
9638 /* friend class C;
9640 where C hasn't been declared yet. Let's lookup name
9641 from namespace scope directly, bypassing any name that
9642 come from dependent base class. */
9645 /* The call to xref_tag_from_type does injection for friend
9646 classes. */
9648 friend_type =
9652 }
9654 /* friend class C<T>; */
9657 /* Otherwise it's
9659 friend class C;
9661 where C is already declared or
9663 friend class C<int>;
9665 We don't have to do anything in these cases. */
9668 /* Trick make_friend_class into realizing that the friend
9669 we're adding is a template, not an ordinary class. It's
9670 important that we use make_friend_class since it will
9671 perform some error-checking and output cross-reference
9672 information. */
9680 }
9681 else
9682 {
9683 /* Build new DECL_FRIENDLIST. */
9684 tree r;
9686 /* The file and line for this declaration, to
9687 assist in error message reporting. Since we
9688 called push_tinst_level above, we don't need to
9689 restore these. */
9693 {
9696 }
9701 {
9704 }
9705 }
9706 }
9707 }
9710 {
9711 /* Restore these before substituting into the lambda capture
9712 initializers. */
9715 }
9718 {
9721 {
9726 /* We need to instantiate the capture list from the template
9727 after we've instantiated the closure members, but before we
9728 consider adding the conversion op. Also keep any captures
9729 that may have been added during instantiation of the op(). */
9731 tree tmpl_cap
9740 }
9741 else
9743 }
9745 /* Set the file and line number information to whatever is given for
9746 the class itself. This puts error messages involving generated
9747 implicit functions at a predictable point, and the same point
9748 that would be used for non-template classes. */
9755 /* We don't instantiate default arguments for member functions. 14.7.1:
9757 The implicit instantiation of a class template specialization causes
9758 the implicit instantiation of the declarations, but not of the
9759 definitions or default arguments, of the class member functions,
9760 member classes, static data members and member templates.... */
9762 /* Some typedefs referenced from within the template code need to be access
9763 checked at template instantiation time, i.e now. These types were
9764 added to the template at parsing time. Let's get those and perform
9765 the access checks then. */
9775 /* The vtable for a template class can be emitted in any translation
9776 unit in which the class is instantiated. When there is no key
9777 method, however, finish_struct_1 will already have added TYPE to
9778 the keyed_classes list. */
9783 }
9785 /* Wrapper for instantiate_class_template_1. */
9787 tree
9789 {
9790 tree ret;
9795 }
9797 static tree
9799 {
9800 tree r;
9806 else
9807 {
9814 }
9816 }
9818 /* Given a function parameter pack TMPL_PARM and some function parameters
9819 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9820 and set *SPEC_P to point at the next point in the list. */
9822 static tree
9824 {
9825 /* Collect all of the extra "packed" parameters into an
9826 argument pack. */
9827 tree parmvec;
9828 tree parmtypevec;
9839 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9844 {
9847 }
9849 /* Build the argument packs. */
9856 }
9858 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9859 NONTYPE_ARGUMENT_PACK. */
9861 static tree
9863 {
9865 }
9867 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
9868 pack expansion with no extra args, 2 if it has extra args, or 0
9869 if it is not a pack expansion. */
9871 static int
9873 {
9883 }
9886 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9888 static tree
9890 {
9897 }
9899 /* This is a subroutine of tsubst_pack_expansion.
9901 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9902 mechanism to store the (non complete list of) arguments of the
9903 substitution and return a non substituted pack expansion, in order
9904 to wait for when we have enough arguments to really perform the
9905 substitution. */
9907 static bool
9911 {
9912 /* If one pack has an expansion and another pack has a normal
9913 argument or if one pack has an empty argument and an another
9914 one hasn't then tsubst_pack_expansion cannot perform the
9915 substitution and need to fall back on the
9916 PACK_EXPANSION_EXTRA mechanism. */
9924 {
9927 parm_pack;
9929 {
9934 /* We can't substitute a pack expansion with extra args into
9935 our pattern. */
9939 else
9941 }
9945 }
9947 }
9949 /* [temp.variadic]/6 says that:
9951 The instantiation of a pack expansion [...]
9952 produces a list E1,E2, ..., En, where N is the number of elements
9953 in the pack expansion parameters.
9955 This subroutine of tsubst_pack_expansion produces one of these Ei.
9957 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9958 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9959 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9960 INDEX is the index 'i' of the element Ei to produce. ARGS,
9961 COMPLAIN, and IN_DECL are the same parameters as for the
9962 tsubst_pack_expansion function.
9964 The function returns the resulting Ei upon successful completion,
9965 or error_mark_node.
9967 Note that this function possibly modifies the ARGS parameter, so
9968 it's the responsibility of the caller to restore it. */
9970 static tree
9972 tree parm_packs,
9974 tree args /* This parm gets
9976 tsubst_flags_t complain,
9977 tree in_decl)
9978 {
9979 tree t;
9982 /* For each parameter pack, change the substitution of the parameter
9983 pack to the ith argument in its argument pack, then expand the
9984 pattern. */
9986 {
9991 ith_elem_is_expansion |=
9994 /* Select the Ith argument from the pack. */
9997 {
9999 {
10003 }
10004 else
10006 }
10007 else
10008 {
10013 {
10015 /* Update the corresponding argument. */
10017 }
10018 else
10019 /* Re-use the ARGUMENT_PACK_SELECT. */
10021 }
10023 }
10025 /* Substitute into the PATTERN with the (possibly altered)
10026 arguments. */
10028 /* Expanding a fixed parameter pack from
10029 coerce_template_parameter_pack. */
10034 else
10037 /* If the Ith argument pack element is a pack expansion, then
10038 the Ith element resulting from the substituting is going to
10039 be a pack expansion as well. */
10044 }
10046 /* Substitute ARGS into T, which is an pack expansion
10047 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
10048 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
10049 (if only a partial substitution could be performed) or
10050 ERROR_MARK_NODE if there was an error. */
10051 tree
10053 tree in_decl)
10054 {
10055 tree pattern;
10059 tree result;
10067 /* Add in any args remembered from an earlier partial instantiation. */
10072 /* Determine the argument packs that will instantiate the parameter
10073 packs used in the expansion expression. While we're at it,
10074 compute the number of arguments to be expanded and make sure it
10075 is consistent. */
10078 {
10085 {
10089 else
10092 }
10094 {
10097 else
10098 {
10099 /* We can't rely on local_specializations for a parameter
10100 name used later in a function declaration (such as in a
10101 late-specified return type). Even if it exists, it might
10102 have the wrong value for a recursive call. Just make a
10103 dummy decl, since it's only used for its type. */
10106 /* Partial instantiation of the parm_pack, we can't build
10107 up an argument pack yet. */
10109 else
10112 }
10113 }
10116 else
10117 {
10123 }
10130 /* This can only happen if we forget to expand an argument
10131 pack somewhere else. Just return an error, silently. */
10132 {
10136 }
10139 {
10143 /* Don't bother trying to do a partial substitution with
10144 incomplete packs; we'll try again after deduction. */
10151 {
10157 pattern);
10158 else
10161 pattern);
10163 }
10165 /* Keep track of the parameter packs and their corresponding
10166 argument packs. */
10169 }
10170 else
10171 {
10172 /* We can't substitute for this parameter pack. We use a flag as
10173 well as the missing_level counter because function parameter
10174 packs don't have a level. */
10176 }
10177 }
10179 /* If the expansion is just T..., return the matching argument pack, unless
10180 we need to call convert_from_reference on all the elements. This is an
10181 important optimization; see c++/68422. */
10184 {
10186 /* Types need no adjustment, nor does sizeof..., and if we still have
10187 some pack expansion args we won't do anything yet. */
10192 /* Otherwise use the normal path so we get convert_from_reference. */
10193 }
10195 /* We cannot expand this expansion expression, because we don't have
10196 all of the argument packs we need. */
10198 {
10199 /* We got some full packs, but we can't substitute them in until we
10200 have values for all the packs. So remember these until then. */
10205 }
10207 {
10208 /* There were no real arguments, we're just replacing a parameter
10209 pack with another version of itself. Substitute into the
10210 pattern and return a PACK_EXPANSION_*. The caller will need to
10211 deal with that. */
10215 else
10219 }
10224 {
10225 /* We're in a late-specified return type, so create our own local
10226 specializations map; the current map is either NULL or (in the
10227 case of recursive unification) might have bindings that we don't
10228 want to use or alter. */
10231 }
10233 /* For each argument in each argument pack, substitute into the
10234 pattern. */
10237 {
10239 i,
10241 in_decl);
10244 {
10247 }
10248 }
10250 /* Update ARGS to restore the substitution from parameter packs to
10251 their argument packs. */
10253 {
10259 else
10260 {
10268 /* Update the corresponding argument. */
10272 else
10274 }
10275 }
10278 {
10281 }
10284 }
10286 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
10287 TMPL. We do this using DECL_PARM_INDEX, which should work even with
10288 parameter packs; all parms generated from a function parameter pack will
10289 have the same DECL_PARM_INDEX. */
10291 tree
10293 {
10295 tree patparm;
10298 {
10304 }
10305 else
10306 {
10311 }
10314 }
10316 /* Substitute ARGS into the vector or list of template arguments T. */
10318 static tree
10320 {
10332 {
10334 tree new_arg;
10339 {
10340 /* Substitute into an expansion expression. */
10344 /* Add to the expanded length adjustment the number of
10345 expanded arguments. We subtract one from this
10346 measurement, because the argument pack expression
10347 itself is already counted as 1 in
10348 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
10349 the argument pack is empty. */
10351 }
10353 {
10354 /* Substitute into each of the arguments. */
10360 new_arg,
10374 }
10375 }
10376 else
10385 }
10390 /* Make space for the expanded arguments coming from template
10391 argument packs. */
10393 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
10394 arguments for a member template.
10395 In that case each TREE_VEC in ORIG_T represents a level of template
10396 arguments, and ORIG_T won't carry any non defaulted argument count.
10397 It will rather be the nested TREE_VECs that will carry one.
10398 In other words, ORIG_T carries a non defaulted argument count only
10399 if it doesn't contain any nested TREE_VEC. */
10401 {
10405 }
10407 {
10411 {
10414 /* Now expand the template argument pack "in place". */
10417 }
10418 else
10419 {
10421 out++;
10422 }
10423 }
10426 }
10428 /* Return the result of substituting ARGS into the template parameters
10429 given by PARMS. If there are m levels of ARGS and m + n levels of
10430 PARMS, then the result will contain n levels of PARMS. For
10431 example, if PARMS is `template <class T> template <class U>
10432 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
10433 result will be `template <int*, double, class V>'. */
10435 static tree
10437 {
10441 /* When substituting into a template, we must set
10442 PROCESSING_TEMPLATE_DECL as the template parameters may be
10443 dependent if they are based on one-another, and the dependency
10444 predicates are short-circuit outside of templates. */
10451 {
10452 tree new_vec =
10457 {
10458 tree tuple;
10470 }
10476 }
10481 }
10483 /* Return the result of substituting ARGS into one template parameter
10484 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
10485 parameter and which TREE_PURPOSE is the default argument of the
10486 template parameter. */
10488 static tree
10490 {
10511 }
10513 /* Substitute the ARGS into the indicated aggregate (or enumeration)
10514 type T. If T is not an aggregate or enumeration type, it is
10515 handled as if by tsubst. IN_DECL is as for tsubst. If
10516 ENTERING_SCOPE is nonzero, T is the context for a template which
10517 we are presently tsubst'ing. Return the substituted value. */
10519 static tree
10521 tree args,
10522 tsubst_flags_t complain,
10523 tree in_decl,
10525 {
10530 {
10535 /* Else fall through. */
10539 {
10540 tree argvec;
10541 tree context;
10542 tree r;
10546 /* In "sizeof(X<I>)" we need to evaluate "I". */
10552 /* First, determine the context for the type we are looking
10553 up. */
10556 {
10559 /* If context is a nested class inside a class template,
10560 it may still need to be instantiated (c++/33959). */
10562 }
10564 /* Then, figure out what arguments are appropriate for the
10565 type we are trying to find. For example, given:
10567 template <class T> struct S;
10568 template <class T, class U> void f(T, U) { S<U> su; }
10570 and supposing that we are instantiating f<int, double>,
10571 then our ARGS will be {int, double}, but, when looking up
10572 S we only want {double}. */
10577 else
10578 {
10582 }
10588 }
10589 else
10590 /* This is not a template type, so there's nothing to do. */
10595 }
10596 }
10598 /* Substitute into the default argument ARG (a default argument for
10599 FN), which has the indicated TYPE. */
10601 tree
10603 {
10608 /* This can happen in invalid code. */
10612 /* This default argument came from a template. Instantiate the
10613 default argument here, not in tsubst. In the case of
10614 something like:
10616 template <class T>
10617 struct S {
10618 static T t();
10619 void f(T = t());
10620 };
10622 we must be careful to do name lookup in the scope of S<T>,
10623 rather than in the current class. */
10625 /* The "this" pointer is not valid in a default argument. */
10627 {
10632 }
10635 /* The default argument expression may cause implicitly defined
10636 member functions to be synthesized, which will result in garbage
10637 collection. We must treat this situation as if we were within
10638 the body of function so as to avoid collecting live data on the
10639 stack. */
10647 /* Restore the "this" pointer. */
10649 {
10652 }
10659 /* Make sure the default argument is reasonable. */
10665 }
10667 /* Substitute into all the default arguments for FN. */
10669 static void
10671 {
10672 tree arg;
10673 tree tmpl_args;
10677 /* If this function is not yet instantiated, we certainly don't need
10678 its default arguments. */
10681 /* Don't do this again for clones. */
10686 arg;
10692 complain);
10693 }
10695 /* Substitute the ARGS into the T, which is a _DECL. Return the
10696 result of the substitution. Issue error and warning messages under
10697 control of COMPLAIN. */
10699 static tree
10701 {
10702 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
10703 location_t saved_loc;
10708 /* Set the filename and linenumber to improve error-reporting. */
10713 {
10715 {
10716 /* We can get here when processing a member function template,
10717 member class template, or template template parameter. */
10719 tree spec;
10720 tree tmpl_args;
10721 tree full_args;
10724 {
10725 /* Template template parameter is treated here. */
10729 /* If we get a real template back, return it. This can happen in
10730 the context of most_specialized_partial_spec. */
10742 complain);
10745 }
10747 /* We might already have an instance of this template.
10748 The ARGS are for the surrounding class type, so the
10749 full args contain the tsubst'd args for the context,
10750 plus the innermost args from the template decl. */
10754 /* Because this is a template, the arguments will still be
10755 dependent, even after substitution. If
10756 PROCESSING_TEMPLATE_DECL is not set, the dependency
10757 predicates will short-circuit. */
10765 /* If this is a default template template argument,
10766 tsubst might not have changed anything. */
10773 {
10776 }
10778 /* Make a new template decl. It will be similar to the
10779 original, but will record the current template arguments.
10780 We also create a new function declaration, which is just
10781 like the old one, but points to this new template, rather
10782 than the old one. */
10791 {
10792 tree new_type;
10800 /* For a partial specialization, we need to keep pointing to
10801 the primary template. */
10807 }
10808 else
10809 {
10810 tree new_decl;
10822 }
10828 /* The template parameters for this new template are all the
10829 template parameters for the old template, except the
10830 outermost level of parameters. */
10833 complain);
10839 /* Record this non-type partial instantiation. */
10843 }
10847 {
10848 tree ctx;
10851 tree gen_tmpl;
10852 tree type;
10857 /* Nobody should be tsubst'ing into non-template functions. */
10861 {
10862 tree spec;
10865 /* If T is not dependent, just return it. We have to
10866 increment PROCESSING_TEMPLATE_DECL because
10867 value_dependent_expression_p assumes that nothing is
10868 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10875 /* Calculate the most general template of which R is a
10876 specialization, and the complete set of arguments used to
10877 specialize R. */
10880 (DECL_TEMPLATE_RESULT
10886 /* Check to see if we already have this specialization. */
10891 {
10894 }
10896 /* We can see more levels of arguments than parameters if
10897 there was a specialization of a member template, like
10898 this:
10900 template <class T> struct S { template <class U> void f(); }
10901 template <> template <class U> void S<int>::f(U);
10903 Here, we'll be substituting into the specialization,
10904 because that's where we can find the code we actually
10905 want to generate, but we'll have enough arguments for
10906 the most general template.
10908 We also deal with the peculiar case:
10910 template <class T> struct S {
10911 template <class U> friend void f();
10912 };
10913 template <class U> void f() {}
10914 template S<int>;
10915 template void f<double>();
10917 Here, the ARGS for the instantiation of will be {int,
10918 double}. But, we only need as many ARGS as there are
10919 levels of template parameters in CODE_PATTERN. We are
10920 careful not to get fooled into reducing the ARGS in
10921 situations like:
10923 template <class T> struct S { template <class U> void f(U); }
10924 template <class T> template <> void S<T>::f(int) {}
10926 which we can spot because the pattern will be a
10927 specialization in this case. */
10929 parms_depth =
10934 }
10935 else
10936 {
10937 /* This special case arises when we have something like this:
10939 template <class T> struct S {
10940 friend void f<int>(int, double);
10941 };
10943 Here, the DECL_TI_TEMPLATE for the friend declaration
10944 will be an IDENTIFIER_NODE. We are being called from
10945 tsubst_friend_function, and we want only to create a
10946 new decl (R) with appropriate types so that we can call
10947 determine_specialization. */
10949 }
10952 {
10955 else
10959 }
10960 else
10961 {
10964 }
10969 /* If we hit excessive deduction depth, the type is bogus even if
10970 it isn't error_mark_node, so don't build a decl. */
10974 /* We do NOT check for matching decls pushed separately at this
10975 point, as they may not represent instantiations of this
10976 template, and in any case are considered separate under the
10977 discrete model. */
10981 /* Clear out the mangled name and RTL for the instantiation. */
10984 /* Leave DECL_INITIAL set on deleted instantiations. */
10989 /* OpenMP UDRs have the only argument a reference to the declared
10990 type. We want to diagnose if the declared type is a reference,
10991 which is invalid, but as references to references are usually
10992 quietly merged, diagnose it here. */
10994 {
10995 tree argtype
11000 "reference type %qT in "
11004 argtype);
11005 }
11008 /* Type-conversion operator. Reconstruct the name, in
11009 case it's the name of one of the template's parameters. */
11019 /* If this is an instantiation of a function with internal
11020 linkage, we already know what object file linkage will be
11021 assigned to the instantiation. */
11030 /* We'll re-clone as appropriate in instantiate_template. */
11033 /* If we aren't complaining now, return on error before we register
11034 the specialization so that we'll complain eventually. */
11040 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
11041 this in the special friend case mentioned above where
11042 GEN_TMPL is NULL. */
11044 {
11049 tree new_r
11052 /* We instantiated this while substituting into
11053 the type earlier (template/friend54.C). */
11056 /* We're not supposed to instantiate default arguments
11057 until they are called, for a template. But, for a
11058 declaration like:
11060 template <class T> void f ()
11061 { extern void g(int i = T()); }
11063 we should do the substitution when the template is
11064 instantiated. We handle the member function case in
11065 instantiate_class_template since the default arguments
11066 might refer to other members of the class. */
11071 }
11072 else
11075 /* Copy the list of befriending classes. */
11079 {
11083 in_decl);
11084 }
11087 {
11093 /* If this is an instantiation of a member template, clone it.
11094 If it isn't, that'll be handled by
11095 clone_constructors_and_destructors. */
11098 }
11109 /* Possibly limit visibility based on template args. */
11112 {
11116 }
11124 }
11128 {
11136 {
11137 /* If there is a local specialization that isn't a
11138 parameter pack, it means that we're doing a "simple"
11139 substitution from inside tsubst_pack_expansion. Just
11140 return the local specialization (which will be a single
11141 parm). */
11148 /* Expand the TYPE_PACK_EXPANSION that provides the types for
11149 the parameters in this function parameter pack. */
11153 {
11156 /* Zero-length parameter packs are boring. Just substitute
11157 into the chain. */
11161 }
11162 else
11163 {
11164 /* All we did was update the type. Make a note of that. */
11167 }
11168 }
11170 /* Loop through all of the parameters we'll build. When T is
11171 a function parameter pack, LEN is the number of expanded
11172 types in EXPANDED_TYPES; otherwise, LEN is 1. */
11175 {
11182 /* We're on the Ith parameter of the function parameter
11183 pack. */
11184 {
11185 /* Get the Ith type. */
11188 /* Rename the parameter to include the index. */
11191 }
11193 /* We're dealing with a normal parameter. */
11201 {
11204 else
11207 }
11217 /* Keep track of the first new parameter we
11218 generate. That's what will be returned to the
11219 caller. */
11223 /* Build a proper chain of parameters when substituting
11224 into a function parameter pack. */
11227 }
11229 /* If cp_unevaluated_operand is set, we're just looking for a
11230 single dummy parameter, so don't keep going. */
11235 /* FIRST_R contains the start of the chain we've built. */
11237 }
11241 {
11248 {
11249 /* This field is a lambda capture pack. Return a TREE_VEC of
11250 the expanded fields to instantiate_class_template_1 and
11251 store them in the specializations hash table as a
11252 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11256 {
11259 }
11260 else
11261 {
11262 /* All we did was update the type. Make a note of that. */
11265 }
11266 }
11269 {
11272 {
11276 }
11286 /* For bit-fields, DECL_INITIAL gives the number of bits. For
11287 non-bit-fields DECL_INITIAL is a non-static data member
11288 initializer, which gets deferred instantiation. */
11294 {
11295 /* Set up DECL_TEMPLATE_INFO so that we can get at the
11296 NSDMI in perform_member_init. Still set DECL_INITIAL
11297 so that we know there is one. */
11302 }
11303 /* We don't have to set DECL_CONTEXT here; it is set by
11304 finish_member_declaration. */
11312 }
11315 {
11323 }
11324 }
11328 /* We reach here only for member using decls. We also need to check
11329 uses_template_parms because DECL_DEPENDENT_P is not set for a
11330 using-declaration that designates a member of the current
11331 instantiation (c++/53549). */
11334 {
11341 else
11342 {
11345 }
11346 }
11347 else
11348 {
11351 }
11356 {
11359 tree spec;
11361 tree ctx;
11370 {
11371 /* If this is the canonical decl, we don't have to
11372 mess with instantiations, and often we can't (for
11373 typename, template type parms and such). Note that
11374 TYPE_NAME is not correct for the above test if
11375 we've copied the type for a typedef. */
11381 }
11383 /* Check to see if we already have the specialization we
11384 need. */
11387 {
11388 /* T is a static data member or namespace-scope entity.
11389 We have to substitute into namespace-scope variables
11390 (not just variable templates) because of cases like:
11392 template <class T> void f() { extern T t; }
11394 where the entity referenced is not known until
11395 instantiation time. */
11399 {
11401 complain,
11403 /* If CTX is unchanged, then T is in fact the
11404 specialization we want. That situation occurs when
11405 referencing a static data member within in its own
11406 class. We can use pointer equality, rather than
11407 same_type_p, because DECL_CONTEXT is always
11408 canonical... */
11410 /* ... unless T is a member template; in which
11411 case our caller can be willing to create a
11412 specialization of that template represented
11413 by T. */
11417 }
11420 {
11425 argvec = (coerce_innermost_template_parms
11433 }
11434 }
11435 else
11436 {
11437 /* A local variable. */
11439 /* Subsequent calls to pushdecl will fill this in. */
11442 }
11443 /* If we already have the specialization we need, there is
11444 nothing more to do. */
11446 {
11449 }
11451 /* Create a new node for the specialization we need. */
11454 {
11457 else
11464 }
11466 {
11467 /* Even if the original location is out of scope, the
11468 newly substituted one is not. */
11475 {
11476 /* It may seem that this case cannot occur, since:
11478 typedef void f();
11479 void g() { f x; }
11481 declares a function, not a variable. However:
11483 typedef void f();
11484 template <typename T> void g() { T t; }
11485 template void g<f>();
11487 is an attempt to declare a variable with function
11488 type. */
11490 /* R is not yet sufficiently initialized, so we
11491 just use its name. */
11494 }
11496 /* Wait until cp_finish_decl to set this again, to handle
11497 circular dependency (template/instantiate6.C). */
11502 {
11507 {
11510 }
11512 }
11515 }
11521 /* Clear out the mangled name and RTL for the instantiation. */
11525 /* The initializer must not be expanded until it is required;
11526 see [temp.inst]. */
11532 {
11533 /* Possibly limit visibility based on template args. */
11536 {
11540 }
11542 }
11545 {
11546 /* A static data member declaration is always marked
11547 external when it is declared in-class, even if an
11548 initializer is present. We mimic the non-template
11549 processing here. */
11557 }
11567 /* Preserve a typedef that names a type. */
11569 {
11573 /* An alias template specialization can be dependent
11574 even if its underlying type is not. */
11576 }
11579 }
11584 }
11585 #undef RETURN
11587 out:
11588 /* Restore the file and line information. */
11592 }
11594 /* Substitute into the ARG_TYPES of a function type.
11595 If END is a TREE_CHAIN, leave it and any following types
11596 un-substituted. */
11598 static tree
11600 tree args,
11601 tree end,
11602 tsubst_flags_t complain,
11603 tree in_decl)
11604 {
11605 tree remaining_arg_types;
11609 tree default_arg;
11620 {
11621 /* For a pack expansion, perform substitution on the
11622 entire expression. Later on, we'll handle the arguments
11623 one-by-one. */
11628 /* So that we'll spin through the parameters, one by one. */
11630 else
11631 {
11632 /* We only partially substituted into the parameter
11633 pack. Our type is TYPE_PACK_EXPANSION. */
11636 }
11637 }
11650 {
11652 {
11656 }
11658 }
11659 /* DR 657. */
11663 /* Do array-to-pointer, function-to-pointer conversion, and ignore
11664 top-level qualifiers as required. */
11667 /* We do not substitute into default arguments here. The standard
11668 mandates that they be instantiated only when needed, which is
11669 done in build_over_call. */
11673 {
11674 /* We've instantiated a template before its default arguments
11675 have been parsed. This can happen for a nested template
11676 class, and is not an error unless we require the default
11677 argument in a call of this function. */
11678 remaining_arg_types =
11681 }
11682 else
11683 remaining_arg_types =
11685 }
11688 }
11690 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
11691 *not* handle the exception-specification for FNTYPE, because the
11692 initial substitution of explicitly provided template parameters
11693 during argument deduction forbids substitution into the
11694 exception-specification:
11696 [temp.deduct]
11698 All references in the function type of the function template to the
11699 corresponding template parameters are replaced by the specified tem-
11700 plate argument values. If a substitution in a template parameter or
11701 in the function type of the function template results in an invalid
11702 type, type deduction fails. [Note: The equivalent substitution in
11703 exception specifications is done only when the function is instanti-
11704 ated, at which point a program is ill-formed if the substitution
11705 results in an invalid type.] */
11707 static tree
11709 tree args,
11710 tsubst_flags_t complain,
11711 tree in_decl)
11712 {
11713 tree return_type;
11715 tree fntype;
11717 /* The TYPE_CONTEXT is not used for function/method types. */
11720 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
11721 failure. */
11725 {
11726 /* Substitute the argument types. */
11738 {
11739 /* DR 1207: 'this' is in scope in the trailing return type. */
11741 }
11743 /* Substitute the return type. */
11747 {
11750 }
11751 }
11752 else
11753 /* Substitute the return type. */
11758 /* DR 486 clarifies that creation of a function type with an
11759 invalid return type is a deduction failure. */
11762 {
11764 {
11767 else
11769 }
11771 }
11772 /* And DR 657. */
11777 {
11778 /* Substitute the argument types. */
11783 }
11785 /* Construct a new type node and return it. */
11787 {
11792 }
11793 else
11794 {
11796 /* Don't pick up extra function qualifiers from the basetype. */
11799 {
11800 /* [temp.deduct]
11802 Type deduction may fail for any of the following
11803 reasons:
11805 -- Attempting to create "pointer to member of T" when T
11806 is not a class type. */
11809 r);
11811 }
11816 }
11823 }
11825 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
11826 ARGS into that specification, and return the substituted
11827 specification. If there is no specification, return NULL_TREE. */
11829 static tree
11831 tree args,
11832 tsubst_flags_t complain,
11833 tree in_decl,
11835 {
11836 tree specs;
11837 tree new_specs;
11842 {
11843 /* A noexcept-specifier. */
11848 {
11849 /* Defer instantiation of noexcept-specifiers to avoid
11850 excessive instantiations (c++/49107). */
11853 {
11854 /* We already partially instantiated this member template,
11855 so combine the new args with the old. */
11860 }
11861 else
11862 {
11865 }
11866 }
11867 else
11868 new_specs = tsubst_copy_and_build
11872 }
11874 {
11877 else
11879 {
11880 tree spec;
11885 {
11886 /* Expand the pack expansion type. */
11889 in_decl);
11895 else
11896 {
11897 /* We're substituting into a member template, so
11898 we got a TYPE_PACK_EXPANSION back. Add that
11899 expansion and move on. */
11903 expanded_specs,
11904 complain);
11907 }
11908 }
11911 {
11914 else
11919 complain);
11920 }
11923 }
11924 }
11926 }
11928 /* Take the tree structure T and replace template parameters used
11929 therein with the argument vector ARGS. IN_DECL is an associated
11930 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11931 Issue error and warning messages under control of COMPLAIN. Note
11932 that we must be relatively non-tolerant of extensions here, in
11933 order to preserve conformance; if we allow substitutions that
11934 should not be allowed, we may allow argument deductions that should
11935 not succeed, and therefore report ambiguous overload situations
11936 where there are none. In theory, we could allow the substitution,
11937 but indicate that it should have failed, and allow our caller to
11938 make sure that the right thing happens, but we don't try to do this
11939 yet.
11941 This function is used for dealing with types, decls and the like;
11942 for expressions, use tsubst_expr or tsubst_copy. */
11944 tree
11946 {
11969 else
11974 /* Reuse typedefs. We need to do this to handle dependent attributes,
11975 such as attribute aligned. */
11978 {
11982 {
11983 /* DECL represents an alias template and we want to
11984 instantiate it. */
11988 }
11992 {
11996 }
12001 else
12002 /* The typedef is from a non-template context. */
12006 {
12008 r = cp_build_qualified_type_real
12012 }
12013 else
12014 {
12015 /* We don't have an instantiation yet, so drop the typedef. */
12020 }
12021 }
12034 {
12060 {
12066 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
12067 needed. */
12073 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
12074 with TREE_SIDE_EFFECTS that indicates this is not an integral
12075 constant expression. */
12078 {
12081 }
12084 }
12090 {
12103 {
12107 {
12108 /* See through ARGUMENT_PACK_SELECT arguments. */
12110 /* If the selected argument is an expansion E, that most
12111 likely means we were called from
12112 gen_elem_of_pack_expansion_instantiation during the
12113 substituting of pack an argument pack (which Ith
12114 element is a pack expansion, where I is
12115 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
12116 In this case, the Ith element resulting from this
12117 substituting is going to be a pack expansion, which
12118 pattern is the pattern of E. Let's return the
12119 pattern of E, and
12120 gen_elem_of_pack_expansion_instantiation will
12121 build the resulting pack expansion from it. */
12123 {
12124 /* Make sure we aren't throwing away arg info. */
12127 }
12128 }
12129 }
12134 {
12136 /* If ARG is an argument pack, we don't actually want to
12137 perform a substitution here, because substitutions
12138 for argument packs are only done
12139 element-by-element. We can get to this point when
12140 substituting the type of a non-type template
12141 parameter pack, when that type actually contains
12142 template parameter packs from an outer template, e.g.,
12144 template<typename... Types> struct A {
12145 template<Types... Values> struct B { };
12146 }; */
12150 {
12156 return cp_build_qualified_type_real
12158 }
12160 {
12161 /* We are processing a type constructed from a
12162 template template parameter. */
12173 /* Consider this code:
12175 template <template <class> class Template>
12176 struct Internal {
12177 template <class Arg> using Bind = Template<Arg>;
12178 };
12180 template <template <class> class Template, class Arg>
12181 using Instantiate = Template<Arg>; //#0
12183 template <template <class> class Template,
12184 class Argument>
12185 using Bind =
12186 Instantiate<Internal<Template>::template Bind,
12187 Argument>; //#1
12189 When #1 is parsed, the
12190 BOUND_TEMPLATE_TEMPLATE_PARM representing the
12191 parameter `Template' in #0 matches the
12192 UNBOUND_CLASS_TEMPLATE representing the argument
12193 `Internal<Template>::template Bind'; We then want
12194 to assemble the type `Bind<Argument>' that can't
12195 be fully created right now, because
12196 `Internal<Template>' not being complete, the Bind
12197 template cannot be looked up in that context. So
12198 we need to "store" `Bind<Argument>' for later
12199 when the context of Bind becomes complete. Let's
12200 store that in a TYPENAME_TYPE. */
12204 argvec),
12205 typename_type,
12206 complain);
12208 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
12209 are resolving nested-types in the signature of a
12210 member function templates. Otherwise ARG is a
12211 TEMPLATE_DECL and is the real template to be
12212 instantiated. */
12220 complain);
12221 return cp_build_qualified_type_real
12223 }
12224 else
12225 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
12227 }
12230 /* This can happen during the attempted tsubst'ing in
12231 unify. This means that we don't yet have any information
12232 about the template parameter in question. */
12235 /* Early in template argument deduction substitution, we don't
12236 want to reduce the level of 'auto', or it will be confused
12237 with a normal template parm in subsequent deduction. */
12241 /* If we get here, we must have been looking at a parm for a
12242 more deeply nested template. Make a new version of this
12243 template parameter, but with a lower level. */
12245 {
12250 {
12252 r = cp_build_qualified_type_real
12256 }
12257 else
12258 {
12269 /* We have reduced the level of the template
12270 template parameter, but not the levels of its
12271 template parameters, so canonical_type_parameter
12272 will not be able to find the canonical template
12273 template parameter for this level. Thus, we
12274 require structural equality checking to compare
12275 TEMPLATE_TEMPLATE_PARMs. */
12279 else
12283 {
12291 }
12292 }
12301 }
12304 }
12307 {
12315 {
12319 }
12322 {
12326 }
12329 {
12333 }
12339 }
12342 /* We should never be tsubsting a binfo. */
12346 /* A vector of template arguments. */
12352 {
12356 /* [temp.deduct]
12358 Type deduction may fail for any of the following
12359 reasons:
12361 -- Attempting to create a pointer to reference type.
12362 -- Attempting to create a reference to a reference type or
12363 a reference to void.
12365 Core issue 106 says that creating a reference to a reference
12366 during instantiation is no longer a cause for failure. We
12367 only enforce this check in strict C++98 mode. */
12371 {
12374 /* We keep track of the last time we issued this error
12375 message to avoid spewing a ton of messages during a
12376 single bad template instantiation. */
12379 {
12384 else
12387 }
12390 }
12394 {
12396 {
12399 type);
12400 else
12402 type);
12403 }
12405 }
12407 {
12411 }
12413 /* In C++0x, during template argument substitution, when there is an
12414 attempt to create a reference to a reference type, reference
12415 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
12417 "If a template-argument for a template-parameter T names a type
12418 that is a reference to a type A, an attempt to create the type
12419 'lvalue reference to cv T' creates the type 'lvalue reference to
12420 A,' while an attempt to create the type type rvalue reference to
12421 cv T' creates the type T"
12422 */
12423 r = cp_build_reference_type
12426 else
12431 /* Will this ever be needed for TYPE_..._TO values? */
12435 }
12437 {
12440 {
12441 /* [temp.deduct]
12443 Type deduction may fail for any of the following
12444 reasons:
12446 -- Attempting to create "pointer to member of T" when T
12447 is not a class type. */
12451 }
12453 {
12457 }
12459 {
12463 }
12466 {
12467 /* The type of the implicit object parameter gets its
12468 cv-qualifiers from the FUNCTION_TYPE. */
12469 tree memptr;
12470 tree method_type
12475 complain);
12476 }
12477 else
12480 complain);
12481 }
12484 {
12485 tree fntype;
12486 tree specs;
12491 /* Substitute the exception specification. */
12499 }
12501 {
12506 /* As an optimization, we avoid regenerating the array type if
12507 it will obviously be the same as T. */
12511 /* These checks should match the ones in create_array_type_for_decl.
12513 [temp.deduct]
12515 The deduction may fail for any of the following reasons:
12517 -- Attempting to create an array with an element type that
12518 is void, a function type, or a reference type, or [DR337]
12519 an abstract class type. */
12525 {
12529 }
12537 {
12540 }
12543 }
12546 {
12556 {
12560 }
12562 {
12563 /* Normally, make_typename_type does not require that the CTX
12564 have complete type in order to allow things like:
12566 template <class T> struct S { typename S<T>::X Y; };
12568 But, such constructs have already been resolved by this
12569 point, so here CTX really should have complete type, unless
12570 it's a partial instantiation. */
12573 {
12577 }
12578 }
12585 {
12588 }
12591 {
12593 {
12597 else
12599 }
12601 {
12605 else
12607 }
12608 }
12610 return cp_build_qualified_type_real
12612 }
12615 {
12627 }
12630 {
12631 tree type;
12647 complain);
12648 }
12651 {
12652 tree type;
12670 else
12671 {
12675 /* In a template ~id could be either a complement expression
12676 or an unqualified-id naming a destructor; if instantiating
12677 it produces an expression, it's not an id-expression or
12678 member access. */
12681 }
12686 }
12689 {
12693 }
12697 {
12699 tree packed_out =
12701 args,
12702 complain,
12703 in_decl);
12706 /* For template nontype argument packs, also substitute into
12707 the type. */
12712 }
12728 /* We should use one of the expression tsubsts for these codes. */
12734 }
12735 }
12737 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
12738 type of the expression on the left-hand side of the "." or "->"
12739 operator. */
12741 static tree
12744 {
12745 tree name;
12746 tree qualifying_scope;
12747 tree fns;
12748 tree optype;
12753 /* A baselink indicates a function from a base class. Both the
12754 BASELINK_ACCESS_BINFO and the base class referenced may
12755 indicate bases of the template class, rather than the
12756 instantiated class. In addition, lookups that were not
12757 ambiguous before may be ambiguous now. Therefore, we perform
12758 the lookup again. */
12765 {
12772 }
12780 /* If lookup found a single function, mark it as used at this
12781 point. (If it lookup found multiple functions the one selected
12782 later by overload resolution will be marked as used at that
12783 point.) */
12789 /* Add back the template arguments, if present. */
12794 template_args);
12795 /* Update the conversion operator type. */
12803 qualifying_scope,
12804 object_type);
12806 }
12808 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
12809 true if the qualified-id will be a postfix-expression in-and-of
12810 itself; false if more of the postfix-expression follows the
12811 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
12812 of "&". */
12814 static tree
12818 {
12819 tree expr;
12820 tree scope;
12821 tree name;
12823 tree template_args;
12828 /* Figure out what name to look up. */
12831 {
12839 }
12840 else
12841 {
12844 }
12846 /* Substitute into the qualifying scope. When there are no ARGS, we
12847 are just trying to simplify a non-dependent expression. In that
12848 case the qualifying scope may be dependent, and, in any case,
12849 substituting will not help. */
12852 {
12855 }
12856 else
12860 {
12865 }
12868 {
12870 {
12871 /* A BIT_NOT_EXPR is used to represent a destructor. */
12873 {
12877 }
12878 else
12881 }
12882 else
12886 {
12888 {
12892 }
12894 }
12895 }
12898 {
12900 scope);
12901 /* Remember that there was a reference to this entity. */
12903 }
12906 {
12912 }
12921 {
12922 expr = (adjust_result_of_qualified_name_lookup
12924 expr = (finish_qualified_id_expr
12928 }
12930 /* Expressions do not generally have reference type. */
12932 /* However, if we're about to form a pointer-to-member, we just
12933 want the referenced member referenced. */
12938 }
12940 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
12941 initializer, DECL is the substituted VAR_DECL. Other arguments are as
12942 for tsubst. */
12944 static tree
12947 {
12954 {
12955 /* If we had an initializer but it
12956 instantiated to nothing,
12957 value-initialize the object. This will
12958 only occur when the initializer was a
12959 pack expansion where the parameter packs
12960 used in that expansion were of length
12961 zero. */
12963 complain);
12966 }
12969 }
12971 /* Like tsubst, but deals with expressions. This function just replaces
12972 template parms; to finish processing the resultant expression, use
12973 tsubst_copy_and_build or tsubst_expr. */
12975 static tree
12977 {
12979 tree r;
12987 {
12992 {
12993 /* We get here for a use of 'this' in an NSDMI. */
12995 && current_function_decl
12999 /* This can happen for a parameter name used later in a function
13000 declaration (such as in a late-specified return type). Just
13001 make a dummy decl, since it's only used for its type. */
13004 /* Give it the template pattern as its context; its true context
13005 hasn't been instantiated yet and this is good enough for
13006 mangling. */
13008 }
13016 {
13017 tree enum_type;
13018 tree v;
13022 /* There is no need to substitute into namespace-scope
13023 enumerators. */
13026 /* If ARGS is NULL, then T is known to be non-dependent. */
13030 /* Unfortunately, we cannot just call lookup_name here.
13031 Consider:
13033 template <int I> int f() {
13034 enum E { a = I };
13035 struct S { void g() { E e = a; } };
13036 };
13038 When we instantiate f<7>::S::g(), say, lookup_name is not
13039 clever enough to find f<7>::a. */
13040 enum_type
13050 /* We didn't find the name. That should never happen; if
13051 name-lookup found it during preliminary parsing, we
13052 should find it again here during instantiation. */
13054 }
13059 {
13060 /* Check for a local specialization set up by
13061 tsubst_pack_expansion. */
13063 {
13067 }
13069 /* When retrieving a capture pack from a generic lambda, remove the
13070 lambda call op's own template argument list from ARGS. Only the
13071 template arguments active for the closure type should be used to
13072 retrieve the pack specialization. */
13078 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
13079 tsubst_decl put in the hash table. */
13081 }
13084 {
13085 tree ctx;
13090 {
13093 {
13097 }
13099 }
13100 }
13109 {
13112 {
13113 /* First try name lookup to find the instantiation. */
13116 {
13117 /* Make sure that the one we found is the one we want. */
13123 }
13127 else
13128 {
13129 /* This can happen for a variable used in a
13130 late-specified return type of a local lambda, or for a
13131 local static or constant. Building a new VAR_DECL
13132 should be OK in all those cases. */
13135 {
13136 /* We can't call cp_finish_decl, so handle the
13137 initializer by hand. */
13148 }
13153 {
13156 at_eof);
13157 else
13159 }
13160 }
13161 /* Remember this for subsequent uses. */
13164 }
13165 }
13166 else
13176 /* An OVERLOAD will always be a non-dependent overload set; an
13177 overload set from function scope will just be represented with an
13178 IDENTIFIER_NODE, and from class scope with a BASELINK. */
13194 {
13195 /* Template template argument like the following example need
13196 special treatment:
13198 template <template <class> class TT> struct C {};
13199 template <class T> struct D {
13200 template <class U> struct E {};
13201 C<E> c; // #1
13202 };
13203 D<int> d; // #2
13205 We are processing the template argument `E' in #1 for
13206 the template instantiation #2. Originally, `E' is a
13207 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
13208 have to substitute this with one having context `D<int>'. */
13212 }
13213 else
13214 /* Ordinary template template argument. */
13225 {
13229 }
13233 {
13242 /* We only want to compute the number of arguments. */
13256 {
13259 else
13265 else
13268 }
13269 else
13271 }
13273 {
13281 }
13282 /* Fall through */
13298 {
13302 }
13305 {
13306 tree object;
13307 tree name;
13312 {
13316 }
13319 {
13329 }
13334 in_decl);
13335 else
13338 }
13376 {
13380 }
13383 {
13388 }
13391 {
13395 }
13398 {
13406 }
13412 {
13419 }
13422 {
13429 }
13432 {
13439 }
13442 {
13443 /* Substituted template arguments */
13452 }
13455 {
13475 }
13500 /* Fall through. */
13503 {
13506 }
13507 else
13511 /* This is handled by tsubst_copy_and_build. */
13515 {
13519 }
13522 /* We shouldn't have built any of these during initial template
13523 generation. Instead, they should be built during instantiation
13524 in response to the saved STMT_IS_FULL_EXPR_P setting. */
13528 {
13536 }
13554 {
13555 /* Instantiate any typedefs in the type. */
13560 }
13563 /* These can sometimes show up in a partial instantiation, but never
13564 involve template parms. */
13569 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
13572 }
13573 }
13575 /* Helper function for tsubst_omp_clauses, used for instantiation of
13576 OMP_CLAUSE_DECL of clauses that handles also OpenMP array sections
13577 represented with TREE_LIST. */
13579 static tree
13581 tree in_decl)
13582 {
13584 {
13585 tree low_bound
13591 in_decl);
13597 }
13599 }
13601 /* Like tsubst_copy, but specifically for OpenMP clauses. */
13603 static tree
13606 {
13610 {
13616 {
13619 {
13625 }
13626 /* FALLTHRU */
13642 in_decl);
13661 {
13664 {
13671 }
13672 else
13674 }
13701 }
13702 }
13708 }
13710 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
13712 static tree
13714 tree in_decl)
13715 {
13716 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
13736 {
13739 else
13740 {
13744 }
13745 }
13750 #undef RECUR
13751 }
13753 /* Substitute one OMP_FOR iterator. */
13755 static void
13760 {
13761 #define RECUR(NODE) \
13762 tsubst_expr ((NODE), args, complain, in_decl, \
13763 integral_constant_expression_p)
13772 {
13773 /* We need to jump through some hoops to handle declarations in the
13774 for-init-statement, since we might need to handle auto deduction,
13775 but we need to keep control of initialization. */
13779 }
13780 else
13792 {
13794 {
13795 /* Declare the variable, but don't let that initialize it. */
13800 }
13805 {
13810 }
13811 else
13818 }
13821 {
13822 /* Declare and initialize the variable. */
13825 }
13827 {
13828 tree c;
13830 {
13841 }
13843 {
13848 {
13851 }
13852 }
13853 }
13856 {
13860 }
13861 else
13865 {
13876 {
13884 }
13885 else
13891 {
13897 }
13901 {
13909 }
13910 else
13916 }
13922 #undef RECUR
13923 }
13925 /* Like tsubst_copy for expressions, etc. but also does semantic
13926 processing. */
13928 static tree
13931 {
13932 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13933 #define RECUR(NODE) \
13934 tsubst_expr ((NODE), args, complain, in_decl, \
13935 integral_constant_expression_p)
13938 tree r;
13939 location_t loc;
13951 {
13953 {
13954 tree_stmt_iterator i;
13958 }
13973 else
13982 {
13984 tree init;
13990 {
13993 tree decl;
14001 else
14003 }
14005 {
14006 /* Don't build up decls for a variadic capture proxy, we'll
14007 instantiate the elements directly as needed. */
14009 }
14010 else
14011 {
14015 {
14016 /* By marking the declaration as instantiated, we avoid
14017 trying to instantiate it. Since instantiate_decl can't
14018 handle local variables, and since we've already done
14019 all that needs to be done, that's the right thing to
14020 do. */
14025 /* Anonymous aggregates are a special case. */
14028 {
14031 {
14035 }
14037 }
14043 {
14048 }
14049 else
14050 {
14055 {
14056 /* For __PRETTY_FUNCTION__ we have to adjust the
14057 initializer. */
14061 }
14062 else
14066 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
14069 }
14070 }
14071 }
14074 }
14089 {
14099 }
14126 {
14130 }
14138 else
14146 else
14167 {
14171 }
14175 {
14177 tree label;
14182 }
14188 /* Computed goto's must be tsubst'd into. On the other hand,
14189 non-computed gotos must not be; the identifier in question
14190 will have no binding. */
14192 else
14198 {
14214 }
14219 {
14224 }
14225 else
14226 {
14231 else
14238 else
14244 else
14246 }
14250 {
14254 {
14256 /* Prevent instantiate_decl from trying to instantiate
14257 this variable. We've already done all that needs to be
14258 done. */
14261 }
14266 }
14272 {
14273 /* Local classes are not independent templates; they are
14274 instantiated along with their containing function. And this
14275 way we don't have to deal with pushing out of one local class
14276 to instantiate a member of another local class. */
14277 tree fn;
14278 /* Closures are handled by the LAMBDA_EXPR. */
14284 }
14288 {
14289 tree condition;
14292 condition =
14294 args,
14303 }
14328 {
14337 {
14342 }
14354 integral_constant_expression_p);
14363 else
14364 {
14372 }
14375 }
14434 {
14439 {
14442 }
14448 }
14449 else
14450 {
14457 {
14460 }
14463 {
14468 {
14471 }
14477 }
14478 else
14479 {
14483 }
14486 }
14490 {
14496 {
14500 {
14505 }
14509 }
14510 else
14511 {
14516 }
14517 }
14521 {
14525 }
14545 /* If the first operand was a statement, we're done with it. */
14549 complain));
14561 integral_constant_expression_p));
14562 }
14565 out:
14568 #undef RECUR
14569 #undef RETURN
14570 }
14572 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
14573 function. For description of the body see comment above
14574 cp_parser_omp_declare_reduction_exprs. */
14576 static void
14578 {
14584 tree_stmt_iterator tsi;
14595 {
14614 }
14616 {
14636 }
14637 }
14639 /* T is a postfix-expression that is not being used in a function
14640 call. Return the substituted version of T. */
14642 static tree
14644 tsubst_flags_t complain,
14645 tree in_decl)
14646 {
14650 else
14656 }
14658 /* Like tsubst but deals with expressions and performs semantic
14659 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
14661 tree
14663 tree args,
14664 tsubst_flags_t complain,
14665 tree in_decl,
14668 {
14669 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
14670 #define RECUR(NODE) \
14671 tsubst_copy_and_build (NODE, args, complain, in_decl, \
14673 integral_constant_expression_p)
14676 location_t loc;
14685 /* N3276 decltype magic only applies to calls at the top level or on the
14686 right side of a comma. */
14691 {
14694 /* Fall through. */
14696 {
14697 tree decl;
14698 cp_id_kind idk;
14703 {
14706 }
14708 /* Look up the name. */
14711 /* By convention, expressions use ERROR_MARK_NODE to indicate
14712 failure, not NULL_TREE. */
14718 integral_constant_expression_p,
14726 input_location);
14730 {
14734 }
14736 }
14739 {
14740 tree object;
14750 {
14753 {
14756 }
14758 }
14761 {
14764 }
14765 else
14772 else
14774 }
14777 {
14781 {
14782 /* A type conversion to reference type will be enclosed in
14783 such an indirect ref, but the substitution of the cast
14784 will have also added such an indirect ref. */
14787 }
14788 else
14792 }
14795 {
14799 }
14802 {
14809 flags));
14810 }
14813 {
14817 }
14824 {
14825 tree type;
14831 {
14836 }
14842 {
14860 }
14863 }
14897 else
14899 in_decl);
14934 {
14939 tree r = build_x_binary_op
14941 op0,
14943 ? ERROR_MARK
14945 op1,
14947 ? ERROR_MARK
14955 }
14958 {
14962 }
14975 {
14984 }
14988 /* Fall through */
14991 {
14992 tree r;
14998 {
14999 /* When there are no ARGS, we are trying to evaluate a
15000 non-dependent expression from the parser. Trying to do
15001 the substitutions may not work. */
15004 }
15005 else
15006 {
15011 else
15014 /*integral_constant_expression_p=*/
15018 }
15022 else
15026 {
15028 {
15030 {
15034 }
15035 else
15039 }
15041 }
15043 }
15046 {
15056 }
15072 {
15076 tree r = build_x_modify_expr
15079 /* TREE_NO_WARNING must be set if either the expression was
15080 parenthesized or it uses an operator such as >>= rather
15081 than plain assignment. In the former case, it was already
15082 set and must be copied. In the latter case,
15083 build_x_modify_expr sets it and it must not be reset
15084 here. */
15089 }
15094 /* Remember that there was a reference to this entity. */
15100 {
15105 tree ret;
15109 else
15110 {
15114 }
15116 /* If there was an initializer in the original tree, but it
15117 instantiated to an empty list, then we should pass a
15118 non-NULL empty vector to tell build_new that it was an
15119 empty initializer() rather than no initializer. This can
15120 only happen when the initializer is a pack expansion whose
15121 parameter packs are of length zero. */
15124 else
15125 {
15129 else
15130 {
15133 }
15134 }
15140 complain);
15148 }
15151 {
15157 complain));
15158 }
15161 {
15165 integral_constant_expression_p);
15167 op0,
15170 }
15173 {
15174 tree function;
15179 tree ret;
15182 /* When we parsed the expression, we determined whether or
15183 not Koenig lookup should be performed. */
15186 {
15191 }
15193 {
15194 /* Do nothing; calling tsubst_copy_and_build on an identifier
15195 would incorrectly perform unqualified lookup again.
15197 Note that we can also have an IDENTIFIER_NODE if the earlier
15198 unqualified lookup found a member function; in that case
15199 koenig_p will be false and we do want to do the lookup
15200 again to find the instantiated member function.
15202 FIXME but doing that causes c++/15272, so we need to stop
15203 using IDENTIFIER_NODE in that situation. */
15205 }
15206 else
15207 {
15209 {
15215 }
15216 else
15221 /* Avoid error about taking the address of a constructor. */
15225 in_decl,
15227 integral_constant_expression_p);
15231 }
15236 {
15241 else
15242 {
15243 /* Expand the pack expansion and push each entry onto
15244 CALL_ARGS. */
15247 {
15252 {
15257 }
15258 }
15259 else
15260 {
15261 /* A partial substitution. Add one entry. */
15263 }
15264 }
15265 }
15267 /* We do not perform argument-dependent lookup if normal
15268 lookup finds a non-function, in accordance with the
15269 expected resolution of DR 218. */
15272 /* If lookup found a member function, the Koenig lookup is
15273 not appropriate, even if an unqualified-name was used
15274 to denote the function. */
15277 /* Only do this when substitution turns a dependent call
15278 into a non-dependent call. */
15285 {
15287 {
15288 /* For backwards compatibility and good diagnostics, try
15289 the unqualified lookup again if we aren't in SFINAE
15290 context. */
15291 tree unq = (tsubst_copy_and_build
15293 integral_constant_expression_p));
15298 {
15307 "%qD was not declared in this scope, "
15308 "and no declarations were found by "
15309 "argument-dependent lookup at the point "
15311 {
15315 {
15317 input_location);
15319 "declarations in dependent base %qT are "
15325 else
15329 }
15330 else
15333 }
15335 }
15336 }
15338 {
15343 }
15344 }
15346 /* Remember that there was a reference to this entity. */
15350 /* Put back tf_decltype for the actual call. */
15355 complain);
15357 {
15372 complain);
15373 else
15374 ret = (build_new_method_call
15379 complain));
15380 }
15381 else
15384 koenig_p,
15385 complain);
15390 }
15393 {
15399 {
15401 {
15406 }
15407 else
15408 {
15413 }
15415 }
15416 else
15417 {
15420 }
15424 }
15427 {
15432 input_location));
15433 }
15436 {
15444 {
15445 /* We have pack expansions, so expand those and
15446 create a new list out of it. */
15449 tree chain;
15452 /* Expand the argument expressions. */
15460 /* Build the rest of the list. */
15465 /* Determine the number of arguments. */
15467 {
15470 }
15473 else
15474 {
15475 /* Since we only performed a partial substitution into
15476 the argument pack, we only RETURN (a single list
15477 node. */
15484 }
15486 /* Convert the argument vectors into a TREE_LIST */
15489 {
15490 /* Grab the Ith values. */
15491 i--;
15494 value
15498 /* Build the list (backwards). */
15500 }
15503 }
15519 }
15522 {
15523 tree object;
15524 tree object_type;
15525 tree member;
15526 tree r;
15530 /* Remember that there was a reference to this entity. */
15540 else
15548 {
15550 {
15555 {
15558 }
15560 {
15565 }
15566 }
15567 }
15570 {
15571 /* Lookup the template functions now that we know what the
15572 scope is. */
15580 {
15583 args);
15584 member = (adjust_result_of_qualified_name_lookup
15586 object_type));
15587 }
15588 else
15589 {
15591 input_location);
15593 }
15594 }
15598 {
15600 {
15604 else
15607 }
15609 }
15611 {
15616 }
15620 complain);
15624 }
15631 {
15639 tree r;
15644 /* digest_init will do the wrong thing if we let it. */
15648 /* We do not want to process the index of aggregate
15649 initializers as they are identifier nodes which will be
15650 looked up by digest_init. */
15656 {
15658 /* An identifier index is looked up in the type
15659 being initialized, not the current scope. */
15664 {
15665 /* Substitute into the pack expansion. */
15667 in_decl);
15671 ;
15673 /* Just move the argument into place. */
15675 else
15676 {
15677 /* Update the length of the final CONSTRUCTOR
15678 arguments vector, and note that we will need to
15679 copy.*/
15682 }
15683 }
15684 else
15686 }
15689 {
15694 {
15696 {
15701 }
15702 else
15704 }
15705 }
15715 }
15718 {
15721 {
15724 }
15725 else
15726 {
15729 }
15730 }
15736 {
15737 /* We don't build decls for an instantiation of a
15738 variadic capture proxy, we instantiate the elements
15739 when needed. */
15742 }
15743 /* Fall through */
15746 {
15748 /* ??? We're doing a subset of finish_id_expression here. */
15750 && !processing_template_decl
15751 && !cp_unevaluated_operand
15754 {
15756 /* Replace an evaluated use of the thread_local variable with
15757 a call to its wrapper. */
15759 }
15761 {
15765 }
15768 /* If the original type was a reference, we'll be wrapped in
15769 the appropriate INDIRECT_REF. */
15772 }
15775 {
15779 }
15786 {
15797 }
15800 {
15806 integral_constant_expression_p);
15810 /* If the resulting list of expression statement is empty,
15811 fold it further into void_node. */
15816 }
15819 {
15833 /* For a function scope, we want to use tsubst so that we don't
15834 complain about referring to an auto function before its return
15835 type has been deduced. Otherwise, we want to use tsubst_copy so
15836 that we look up the existing field/parameter/variable rather
15837 than build a new one. */
15842 {
15843 /* Look up the parameter we want directly, as tsubst_copy
15844 doesn't do what we need. */
15850 /* FIXME Work around the parm not having DECL_CONTEXT set. */
15853 }
15854 else
15863 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
15865 /* Now that we know visibility, instantiate the type so we have a
15866 declaration of the op() for later calls to lambda_function. */
15874 }
15877 /* We can get here for a constant initializer of non-dependent type.
15878 FIXME stop folding in cp_parser_initializer_clause. */
15879 {
15881 complain);
15883 }
15887 integral_constant_expression_p));
15893 {
15898 complain));
15899 }
15902 /* Handle Objective-C++ constructs, if appropriate. */
15903 {
15904 tree subst
15909 }
15911 }
15913 #undef RECUR
15914 #undef RETURN
15915 out:
15918 }
15920 /* Verify that the instantiated ARGS are valid. For type arguments,
15921 make sure that the type's linkage is ok. For non-type arguments,
15922 make sure they are constants if they are integral or enumerations.
15923 Emit an error under control of COMPLAIN, and return TRUE on error. */
15925 static bool
15927 {
15931 {
15941 }
15943 {
15944 /* [basic.link]: A name with no linkage (notably, the name
15945 of a class or enumeration declared in a local scope)
15946 shall not be used to declare an entity with linkage.
15947 This implies that names with no linkage cannot be used as
15948 template arguments
15950 DR 757 relaxes this restriction for C++0x. */
15955 {
15956 /* DR 488 makes use of a type with no linkage cause
15957 type deduction to fail. */
15959 {
15962 else
15965 }
15967 }
15968 /* In order to avoid all sorts of complications, we do not
15969 allow variably-modified types as template arguments. */
15971 {
15975 }
15976 }
15977 /* Class template and alias template arguments should be OK. */
15979 ;
15980 /* A non-type argument of integral or enumerated type must be a
15981 constant. */
15986 {
15990 }
15992 }
15994 static bool
15996 {
16001 {
16004 }
16008 }
16010 /* We're out of SFINAE context now, so generate diagnostics for the access
16011 errors we saw earlier when instantiating D from TMPL and ARGS. */
16013 static void
16015 {
16027 }
16029 /* Instantiate the indicated variable, function, or alias template TMPL with
16030 the template arguments in TARG_PTR. */
16032 static tree
16034 {
16036 tree fndecl;
16037 tree gen_tmpl;
16038 tree spec;
16046 /* If this function is a clone, handle it specially. */
16048 {
16049 tree spec;
16050 tree clone;
16052 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
16053 DECL_CLONED_FUNCTION. */
16059 /* Look for the clone. */
16063 /* We should always have found the clone by now. */
16066 }
16071 /* Check to see if we already have this specialization. */
16074 /* The TMPL is a partial instantiation. To get a full set of
16075 arguments we must add the arguments used to perform the
16076 partial instantiation. */
16078 targ_ptr);
16080 /* It would be nice to avoid hashing here and then again in tsubst_decl,
16081 but it doesn't seem to be on the hot path. */
16090 {
16092 {
16096 }
16098 }
16101 complain))
16104 /* We are building a FUNCTION_DECL, during which the access of its
16105 parameters and return types have to be checked. However this
16106 FUNCTION_DECL which is the desired context for access checking
16107 is not built yet. We solve this chicken-and-egg problem by
16108 deferring all checks until we have the FUNCTION_DECL. */
16111 /* Instantiation of the function happens in the context of the function
16112 template, not the context of the overload resolution we're doing. */
16114 /* If there are dependent arguments, e.g. because we're doing partial
16115 ordering, make sure processing_template_decl stays set. */
16119 {
16123 }
16128 {
16129 /* We need to determine if we're using a partial or explicit
16130 specialization now, because the type of the variable could be
16131 different. */
16137 {
16141 }
16142 }
16144 /* Substitute template parameters to obtain the specialization. */
16151 {
16154 }
16156 /* The DECL_TI_TEMPLATE should always be the immediate parent
16157 template, not the most general template. */
16162 /* Now we know the specialization, compute access previously
16163 deferred. */
16170 /* If we've just instantiated the main entry point for a function,
16171 instantiate all the alternate entry points as well. We do this
16172 by cloning the instantiation of the main entry point, not by
16173 instantiating the template clones. */
16178 {
16180 {
16181 /* Remember to reinstantiate when we're out of SFINAE so the user
16182 can see the errors. */
16184 }
16186 }
16188 }
16190 /* Wrapper for instantiate_template_1. */
16192 tree
16194 {
16195 tree ret;
16200 }
16202 /* Instantiate the alias template TMPL with ARGS. Also push a template
16203 instantiation level, which instantiate_template doesn't do because
16204 functions and variables have sufficient context established by the
16205 callers. */
16207 static tree
16209 {
16216 {
16219 }
16221 args =
16229 /* We can't free this if a pending_template entry or last_error_tinst_level
16230 is pointing at it. */
16236 }
16238 /* PARM is a template parameter pack for FN. Returns true iff
16239 PARM is used in a deducible way in the argument list of FN. */
16241 static bool
16243 {
16246 {
16248 tree packs;
16254 {
16255 /* The template parameter pack is used in a function parameter
16256 pack. If this is the end of the parameter list, the
16257 template parameter pack is deducible. */
16260 else
16261 /* Otherwise, not. Well, it could be deduced from
16262 a non-pack parameter, but doing so would end up with
16263 a deduction mismatch, so don't bother. */
16265 }
16266 }
16267 /* The template parameter pack isn't used in any function parameter
16268 packs, but it might be used deeper, e.g. tuple<Args...>. */
16270 }
16272 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
16273 NARGS elements of the arguments that are being used when calling
16274 it. TARGS is a vector into which the deduced template arguments
16275 are placed.
16277 Returns either a FUNCTION_DECL for the matching specialization of FN or
16278 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
16279 true, diagnostics will be printed to explain why it failed.
16281 If FN is a conversion operator, or we are trying to produce a specific
16282 specialization, RETURN_TYPE is the return type desired.
16284 The EXPLICIT_TARGS are explicit template arguments provided via a
16285 template-id.
16287 The parameter STRICT is one of:
16289 DEDUCE_CALL:
16290 We are deducing arguments for a function call, as in
16291 [temp.deduct.call].
16293 DEDUCE_CONV:
16294 We are deducing arguments for a conversion function, as in
16295 [temp.deduct.conv].
16297 DEDUCE_EXACT:
16298 We are deducing arguments when doing an explicit instantiation
16299 as in [temp.explicit], when determining an explicit specialization
16300 as in [temp.expl.spec], or when taking the address of a function
16301 template, as in [temp.deduct.funcaddr]. */
16303 tree
16305 tree explicit_targs,
16306 tree targs,
16309 tree return_type,
16310 unification_kind_t strict,
16314 {
16315 tree parms;
16316 tree fntype;
16324 tree tinst;
16330 /* In C++0x, it's possible to have a function template whose type depends
16331 on itself recursively. This is most obvious with decltype, but can also
16332 occur with enumeration scope (c++/48969). So we need to catch infinite
16333 recursion and reject the substitution at deduction time; this function
16334 will return error_mark_node for any repeated substitution.
16336 This also catches excessive recursion such as when f<N> depends on
16337 f<N-1> across all integers, and returns error_mark_node for all the
16338 substitutions back up to the initial one.
16340 This is, of course, not reentrant. */
16350 {
16351 /* [temp.deduct]
16353 The specified template arguments must match the template
16354 parameters in kind (i.e., type, nontype, template), and there
16355 must not be more arguments than there are parameters;
16356 otherwise type deduction fails.
16358 Nontype arguments must match the types of the corresponding
16359 nontype template parameters, or must be convertible to the
16360 types of the corresponding nontype parameters as specified in
16361 _temp.arg.nontype_, otherwise type deduction fails.
16363 All references in the function type of the function template
16364 to the corresponding template parameters are replaced by the
16365 specified template argument values. If a substitution in a
16366 template parameter or in the function type of the function
16367 template results in an invalid type, type deduction fails. */
16372 /* Adjust any explicit template arguments before entering the
16373 substitution context. */
16374 explicit_targs
16376 complain,
16382 /* Substitute the explicit args into the function type. This is
16383 necessary so that, for instance, explicitly declared function
16384 arguments can match null pointed constants. If we were given
16385 an incomplete set of explicit args, we must not do semantic
16386 processing during substitution as we could create partial
16387 instantiations. */
16389 {
16394 /* Dig out the actual parm. */
16397 {
16400 }
16402 {
16405 }
16408 /* No explicit argument for this template parameter. */
16412 {
16413 /* Mark the argument pack as "incomplete". We could
16414 still deduce more arguments during unification.
16415 We remove this mark in type_unification_real. */
16417 {
16421 }
16423 /* We have some incomplete argument packs. */
16425 }
16426 }
16430 {
16433 }
16436 /* Ignore any access checks; we'll see them again in
16437 instantiate_template and they might have the wrong
16438 access path at this point. */
16450 /* Place the explicitly specified arguments in TARGS. */
16453 }
16455 /* Never do unification on the 'this' parameter. */
16459 {
16468 }
16470 /* We allow incomplete unification without an error message here
16471 because the standard doesn't seem to explicitly prohibit it. Our
16472 callers must be ready to deal with unification failures in any
16473 event. */
16476 /* If we aren't explaining yet, push tinst context so we can see where
16477 any errors (e.g. from class instantiations triggered by instantiation
16478 of default template arguments) come from. If we are explaining, this
16479 context is redundant. */
16481 {
16484 }
16486 /* type_unification_real will pass back any access checks from default
16487 template argument substitution. */
16499 /* Now that we have bindings for all of the template arguments,
16500 ensure that the arguments deduced for the template template
16501 parameters have compatible template parameter lists. We cannot
16502 check this property before we have deduced all template
16503 arguments, because the template parameter types of a template
16504 template parameter might depend on prior template parameters
16505 deduced after the template template parameter. The following
16506 ill-formed example illustrates this issue:
16508 template<typename T, template<T> class C> void f(C<5>, T);
16510 template<int N> struct X {};
16512 void g() {
16513 f(X<5>(), 5l); // error: template argument deduction fails
16514 }
16516 The template parameter list of 'C' depends on the template type
16517 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
16518 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
16519 time that we deduce 'C'. */
16522 {
16525 }
16527 /* All is well so far. Now, check:
16529 [temp.deduct]
16531 When all template arguments have been deduced, all uses of
16532 template parameters in nondeduced contexts are replaced with
16533 the corresponding deduced argument values. If the
16534 substitution results in an invalid type, as described above,
16535 type deduction fails. */
16538 {
16541 }
16543 /* Also collect access checks from the instantiation. */
16556 /* Now perform any access checks encountered during substitution. */
16563 /* If we're looking for an exact match, check that what we got
16564 is indeed an exact match. It might not be if some template
16565 parameters are used in non-deduced contexts. But don't check
16566 for an exact match if we have dependent template arguments;
16567 in that case we're doing partial ordering, and we already know
16568 that we have two candidates that will provide the actual type. */
16570 {
16574 tree sarg
16580 {
16584 }
16585 }
16589 fail:
16592 {
16594 /* Reset once we're all the way out. */
16596 }
16598 /* We can't free this if a pending_template entry or last_error_tinst_level
16599 is pointing at it. */
16605 }
16607 /* Adjust types before performing type deduction, as described in
16608 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
16609 sections are symmetric. PARM is the type of a function parameter
16610 or the return type of the conversion function. ARG is the type of
16611 the argument passed to the call, or the type of the value
16612 initialized with the result of the conversion function.
16613 ARG_EXPR is the original argument expression, which may be null. */
16615 static int
16619 tree arg_expr)
16620 {
16624 {
16629 {
16630 /* Swap PARM and ARG throughout the remainder of this
16631 function; the handling is precisely symmetric since PARM
16632 will initialize ARG rather than vice versa. */
16637 }
16640 /* Core issue #873: Do the DR606 thing (see below) for these cases,
16641 too, but here handle it by stripping the reference from PARM
16642 rather than by adding it to ARG. */
16650 /* Nothing else to do in this case. */
16655 }
16658 {
16659 /* [temp.deduct.call]
16661 If P is not a reference type:
16663 --If A is an array type, the pointer type produced by the
16664 array-to-pointer standard conversion (_conv.array_) is
16665 used in place of A for type deduction; otherwise,
16667 --If A is a function type, the pointer type produced by
16668 the function-to-pointer standard conversion
16669 (_conv.func_) is used in place of A for type deduction;
16670 otherwise,
16672 --If A is a cv-qualified type, the top level
16673 cv-qualifiers of A's type are ignored for type
16674 deduction. */
16679 else
16681 }
16683 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
16684 of the form T&&, where T is a template parameter, and the argument
16685 is an lvalue, T is deduced as A& */
16691 /* try_one_overload doesn't provide an arg_expr, but
16692 functions are always lvalues. */
16696 /* [temp.deduct.call]
16698 If P is a cv-qualified type, the top level cv-qualifiers
16699 of P's type are ignored for type deduction. If P is a
16700 reference type, the type referred to by P is used for
16701 type deduction. */
16704 {
16707 }
16709 /* DR 322. For conversion deduction, remove a reference type on parm
16710 too (which has been swapped into ARG). */
16715 }
16717 /* Subroutine of unify_one_argument. PARM is a function parameter of a
16718 template which does contain any deducible template parameters; check if
16719 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
16720 unify_one_argument. */
16722 static int
16725 {
16726 tree type;
16730 else
16737 {
16741 }
16743 {
16748 }
16752 else
16754 }
16758 /* Returns true iff the expression EXPR is one from which a template
16759 argument can be deduced. In other words, if it's an undecorated
16760 use of a template non-type parameter. */
16762 static bool
16764 {
16766 }
16768 /* Returns true iff the array domain DOMAIN uses a template parameter in a
16769 deducible way; that is, if it has a max value of <PARM> - 1. */
16771 static bool
16773 {
16782 }
16784 /* Returns true iff the template arguments ARGS use a template parameter
16785 in a deducible way. */
16787 static bool
16789 {
16791 {
16796 else
16797 {
16804 else
16806 }
16809 }
16811 }
16813 /* Returns true iff TYPE contains any deducible references to template
16814 parameters, as per 14.8.2.5. */
16816 static bool
16818 {
16822 /* T
16823 cv-list T
16824 TT<T>
16825 TT<i>
16826 TT<> */
16831 /* T*
16832 T&
16833 T&& */
16837 /* T[integer-constant ]
16838 type [i] */
16843 /* T type ::*
16844 type T::*
16845 T T::*
16846 T (type ::*)()
16847 type (T::*)()
16848 type (type ::*)(T)
16849 type (T::*)(T)
16850 T (type ::*)(T)
16851 T (T::*)()
16852 T (T::*)(T) */
16855 || (uses_deducible_template_parms
16858 /* template-name <T> (where template-name refers to a class template)
16859 template-name <i> (where template-name refers to a class template) */
16866 /* type (T)
16867 T()
16868 T(T) */
16871 {
16880 }
16883 }
16885 /* Subroutine of type_unification_real and unify_pack_expansion to
16886 handle unification of a single P/A pair. Parameters are as
16887 for those functions. */
16889 static int
16893 {
16900 /* We can't deduce anything from this, but we might get all the
16901 template args from other function args. */
16904 /* Implicit conversions (Clause 4) will be performed on a function
16905 argument to convert it to the type of the corresponding function
16906 parameter if the parameter type contains no template-parameters that
16907 participate in template argument deduction. */
16909 /* For function parameters that contain no template-parameters at all,
16910 we have historically checked for convertibility in order to shortcut
16911 consideration of this candidate. */
16913 explain_p);
16916 /* For function parameters with only non-deducible template parameters,
16917 just return. */
16921 {
16923 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
16924 | UNIFY_ALLOW_MORE_CV_QUAL
16938 }
16940 /* We only do these transformations if this is the top-level
16941 parameter_type_list in a call or declaration matching; in other
16942 situations (nested function declarators, template argument lists) we
16943 won't be comparing a type to an expression, and we don't do any type
16944 adjustments. */
16946 {
16948 {
16951 {
16952 /* [temp.deduct.type] A template-argument can be
16953 deduced from a pointer to function or pointer
16954 to member function argument if the set of
16955 overloaded functions does not contain function
16956 templates and at most one of a set of
16957 overloaded functions provides a unique
16958 match. */
16965 }
16971 }
16973 arg_strict |=
16975 }
16976 else
16981 /* For deduction from an init-list we need the actual list. */
16985 }
16987 /* Most parms like fn_type_unification.
16989 If SUBR is 1, we're being called recursively (to unify the
16990 arguments of a function or method parameter of a function
16991 template).
16993 CHECKS is a pointer to a vector of access checks encountered while
16994 substituting default template arguments. */
16996 static int
16998 tree targs,
16999 tree xparms,
17003 unification_kind_t strict,
17007 {
17012 tree parms;
17021 /* Reset the number of non-defaulted template arguments contained
17022 in TARGS. */
17025 again:
17033 {
17038 /* For a function parameter pack that occurs at the end of the
17039 parameter-declaration-list, the type A of each remaining
17040 argument of the call is compared with the type P of the
17041 declarator-id of the function parameter pack. */
17047 /* For a function parameter pack that does not occur at the
17048 end of the parameter-declaration-list, the type of the
17049 parameter pack is a non-deduced context. */
17058 }
17063 {
17064 /* Unify the remaining arguments with the pack expansion type. */
17065 tree argvec;
17068 /* Allocate a TREE_VEC and copy in all of the arguments */
17073 /* Copy the parameter into parmvec. */
17079 /* Advance to the end of the list of parameters. */
17081 }
17083 /* Fail if we've reached the end of the parm list, and more args
17084 are present, and the parm list isn't variadic. */
17087 /* Fail if parms are left and they don't have default values and
17088 they aren't all deduced as empty packs (c++/57397). This is
17089 consistent with sufficient_parms_p. */
17092 {
17096 do
17097 {
17100 count++;
17102 }
17106 type_pack_p);
17107 }
17110 {
17111 tsubst_flags_t complain = (explain_p
17112 ? tf_warning_or_error
17116 {
17120 /* Clear the "incomplete" flags on all argument packs now so that
17121 substituting them into later default arguments works. */
17123 {
17126 }
17132 /* If this is an undeduced nontype parameter that depends on
17133 a type parameter, try another pass; its type may have been
17134 deduced from a later argument than the one from which
17135 this parameter can be deduced. */
17141 /* Core issue #226 (C++0x) [temp.deduct]:
17143 If a template argument has not been deduced, its
17144 default template argument, if any, is used.
17146 When we are in C++98 mode, TREE_PURPOSE will either
17147 be NULL_TREE or ERROR_MARK_NODE, so we do not need
17148 to explicitly check cxx_dialect here. */
17150 {
17165 else
17166 {
17168 /* The position of the first default template argument,
17169 is also the number of non-defaulted arguments in TARGS.
17170 Record that. */
17174 }
17175 }
17177 /* If the type parameter is a parameter pack, then it will
17178 be deduced to an empty parameter pack. */
17180 {
17181 tree arg;
17184 {
17188 }
17189 else
17196 }
17199 }
17200 }
17201 #ifdef ENABLE_CHECKING
17204 #endif
17207 }
17209 /* Subroutine of type_unification_real. Args are like the variables
17210 at the call site. ARG is an overloaded function (or template-id);
17211 we try deducing template args from each of the overloads, and if
17212 only one succeeds, we go with that. Modifies TARGS and returns
17213 true on success. */
17215 static bool
17217 tree targs,
17218 tree parm,
17219 tree arg,
17220 unification_kind_t strict,
17223 {
17230 {
17233 }
17234 else
17238 /* Handle `&x' where `x' is some static or non-static member
17239 function name. */
17245 /* Strip baselink information. */
17250 {
17251 /* If we got some explicit template args, we need to plug them into
17252 the affected templates before we try to unify, in case the
17253 explicit args will completely resolve the templates in question. */
17260 {
17273 {
17278 {
17281 }
17282 }
17285 }
17286 /* If no templates (or more than one) are fully resolved by the
17287 explicit arguments, this template-id is a non-deduced context; it
17288 could still be OK if we deduce all template arguments for the
17289 enclosing call through other arguments. */
17292 }
17295 /* If ARG is, for example, "(0, &f)" then its type will be unknown
17296 -- but the deduction does not succeed because the expression is
17297 not just the function on its own. */
17299 else
17305 {
17308 }
17310 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17311 to function or pointer to member function argument if the set of
17312 overloaded functions does not contain function templates and at most
17313 one of a set of overloaded functions provides a unique match.
17315 So if we found multiple possibilities, we return success but don't
17316 deduce anything. */
17319 {
17323 {
17328 /* Don't forget explicit template arguments in a pack. */
17332 }
17333 }
17338 }
17340 /* Core DR 115: In contexts where deduction is done and fails, or in
17341 contexts where deduction is not done, if a template argument list is
17342 specified and it, along with any default template arguments, identifies
17343 a single function template specialization, then the template-id is an
17344 lvalue for the function template specialization. */
17346 tree
17348 {
17361 {
17364 }
17366 {
17369 }
17371 {
17374 }
17377 {
17381 /* If we got some explicit template args, we need to plug them into
17382 the affected templates before we try to unify, in case the
17383 explicit args will completely resolve the templates in question. */
17391 {
17404 {
17407 {
17410 }
17412 {
17415 }
17416 }
17417 }
17419 {
17427 {
17428 tree base
17431 }
17435 }
17437 /* There were no good options and at least one bad one, so let the
17438 user know what the problem is. */
17440 }
17442 }
17444 /* Subroutine of resolve_overloaded_unification; does deduction for a single
17445 overload. Fills TARGS with any deduced arguments, or error_mark_node if
17446 different overloads deduce different arguments for a given parm.
17447 ADDR_P is true if the expression for which deduction is being
17448 performed was of the form "& fn" rather than simply "fn".
17450 Returns 1 on success. */
17452 static int
17454 tree orig_targs,
17455 tree targs,
17456 tree parm,
17457 tree arg,
17458 unification_kind_t strict,
17462 {
17464 tree tempargs;
17470 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17471 to function or pointer to member function argument if the set of
17472 overloaded functions does not contain function templates and at most
17473 one of a set of overloaded functions provides a unique match.
17475 So if this is a template, just return success. */
17487 /* We don't copy orig_targs for this because if we have already deduced
17488 some template args from previous args, unify would complain when we
17489 try to deduce a template parameter for the same argument, even though
17490 there isn't really a conflict. */
17497 /* First make sure we didn't deduce anything that conflicts with
17498 explicitly specified args. */
17500 {
17507 /* Since we're unifying against ourselves, we will fill in
17508 template args used in the function parm list with our own
17509 template parms. Discard them. */
17513 }
17516 {
17521 }
17524 }
17526 /* PARM is a template class (perhaps with unbound template
17527 parameters). ARG is a fully instantiated type. If ARG can be
17528 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
17529 TARGS are as for unify. */
17531 static tree
17534 {
17535 tree copy_of_targs;
17542 /* We need to make a new template argument vector for the call to
17543 unify. If we used TARGS, we'd clutter it up with the result of
17544 the attempted unification, even if this class didn't work out.
17545 We also don't want to commit ourselves to all the unifications
17546 we've already done, since unification is supposed to be done on
17547 an argument-by-argument basis. In other words, consider the
17548 following pathological case:
17550 template <int I, int J, int K>
17551 struct S {};
17553 template <int I, int J>
17554 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
17556 template <int I, int J, int K>
17557 void f(S<I, J, K>, S<I, I, I>);
17559 void g() {
17560 S<0, 0, 0> s0;
17561 S<0, 1, 2> s2;
17563 f(s0, s2);
17564 }
17566 Now, by the time we consider the unification involving `s2', we
17567 already know that we must have `f<0, 0, 0>'. But, even though
17568 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
17569 because there are two ways to unify base classes of S<0, 1, 2>
17570 with S<I, I, I>. If we kept the already deduced knowledge, we
17571 would reject the possibility I=1. */
17574 /* If unification failed, we're done. */
17580 }
17582 /* Given a template type PARM and a class type ARG, find the unique
17583 base type in ARG that is an instance of PARM. We do not examine
17584 ARG itself; only its base-classes. If there is not exactly one
17585 appropriate base class, return NULL_TREE. PARM may be the type of
17586 a partial specialization, as well as a plain template type. Used
17587 by unify. */
17589 static enum template_base_result
17592 {
17594 tree binfo;
17600 {
17601 /* The type could not be completed. */
17604 }
17606 /* Walk in inheritance graph order. The search order is not
17607 important, and this avoids multiple walks of virtual bases. */
17609 {
17614 {
17615 /* If there is more than one satisfactory baseclass, then:
17617 [temp.deduct.call]
17619 If they yield more than one possible deduced A, the type
17620 deduction fails.
17622 applies. */
17624 {
17627 }
17630 }
17631 }
17635 }
17637 /* Returns the level of DECL, which declares a template parameter. */
17639 static int
17641 {
17643 {
17653 }
17655 }
17657 /* Decide whether ARG can be unified with PARM, considering only the
17658 cv-qualifiers of each type, given STRICT as documented for unify.
17659 Returns nonzero iff the unification is OK on that basis. */
17661 static int
17663 {
17669 {
17670 /* Although a CVR qualifier is ignored when being applied to a
17671 substituted template parameter ([8.3.2]/1 for example), that
17672 does not allow us to unify "const T" with "int&" because both
17673 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
17674 It is ok when we're allowing additional CV qualifiers
17675 at the outer level [14.8.2.1]/3,1st bullet. */
17685 }
17696 }
17698 /* Determines the LEVEL and INDEX for the template parameter PARM. */
17699 void
17701 {
17705 {
17708 }
17709 else
17710 {
17713 }
17714 }
17716 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
17717 do { \
17718 if (unify (TP, TA, P, A, S, EP)) \
17719 return 1; \
17720 } while (0);
17722 /* Unifies the remaining arguments in PACKED_ARGS with the pack
17723 expansion at the end of PACKED_PARMS. Returns 0 if the type
17724 deduction succeeds, 1 otherwise. STRICT is the same as in
17725 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
17726 call argument list. We'll need to adjust the arguments to make them
17727 types. SUBR tells us if this is from a recursive call to
17728 type_unification_real, or for comparing two template argument
17729 lists. */
17731 static int
17735 {
17736 tree parm
17746 /* Determine the parameter packs we will be deducing from the
17747 pattern, and record their current deductions. */
17750 {
17754 /* Determine the index and level of this parameter pack. */
17757 /* Keep track of the parameter packs and their corresponding
17758 argument packs. */
17761 }
17763 /* Loop through all of the arguments that have not yet been
17764 unified and unify each with the pattern. */
17766 {
17767 tree parm;
17771 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
17772 or the element of its argument pack at the current index if
17773 this argument was explicitly specified. */
17775 {
17784 {
17787 }
17789 }
17791 /* If we had explicit template arguments, substitute them into the
17792 pattern before deduction. */
17794 {
17795 /* Some arguments might still be unspecified or dependent. */
17803 NULL_TREE);
17808 }
17809 else
17812 /* Unify the pattern with the current argument. */
17817 /* For each parameter pack, collect the deduced value. */
17819 {
17825 }
17826 }
17828 /* Verify that the results of unification with the parameter packs
17829 produce results consistent with what we've seen before, and make
17830 the deduced argument packs available. */
17832 {
17839 /* By default keep the original deduced argument pack.
17840 If necessary, more specific code is going to update the
17841 resulting deduced argument later down in this function. */
17845 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
17846 actually deduce anything. */
17854 {
17855 /* If we had fewer function args than explicit template args,
17856 just use the explicits. */
17861 }
17864 {
17865 tree result;
17866 /* Build the deduced *_ARGUMENT_PACK. */
17868 {
17873 }
17874 else
17879 /* Note the deduced argument packs for this parameter
17880 pack. */
17882 }
17886 {
17887 /* We only had the explicitly-provided arguments before, but
17888 now we have a complete set of arguments. */
17894 }
17895 else
17896 {
17902 /* Inconsistent unification of this parameter pack. */
17904 bad_old_arg,
17905 bad_new_arg);
17906 }
17907 }
17910 }
17912 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
17913 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
17914 parameters and return value are as for unify. */
17916 static int
17920 {
17921 tree parm_max;
17922 tree arg_max;
17926 /* Our representation of array types uses "N - 1" as the
17927 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
17928 not an integer constant. We cannot unify arbitrarily
17929 complex expressions, so we eliminate the MINUS_EXPRs
17930 here. */
17934 {
17937 }
17941 {
17942 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
17943 trying to unify the type of a variable with the type
17944 of a template parameter. For example:
17946 template <unsigned int N>
17947 void f (char (&) [N]);
17948 int g();
17949 void h(int i) {
17950 char a[g(i)];
17951 f(a);
17952 }
17954 Here, the type of the ARG will be "int [g(i)]", and
17955 may be a SAVE_EXPR, etc. */
17959 }
17961 /* If only one of the bounds used a MINUS_EXPR, compensate
17962 by adding one to the other bound. */
17965 integer_type_node,
17966 parm_max,
17967 integer_one_node);
17970 integer_type_node,
17971 arg_max,
17972 integer_one_node);
17976 }
17978 /* Deduce the value of template parameters. TPARMS is the (innermost)
17979 set of template parameters to a template. TARGS is the bindings
17980 for those template parameters, as determined thus far; TARGS may
17981 include template arguments for outer levels of template parameters
17982 as well. PARM is a parameter to a template function, or a
17983 subcomponent of that parameter; ARG is the corresponding argument.
17984 This function attempts to match PARM with ARG in a manner
17985 consistent with the existing assignments in TARGS. If more values
17986 are deduced, then TARGS is updated.
17988 Returns 0 if the type deduction succeeds, 1 otherwise. The
17989 parameter STRICT is a bitwise or of the following flags:
17991 UNIFY_ALLOW_NONE:
17992 Require an exact match between PARM and ARG.
17993 UNIFY_ALLOW_MORE_CV_QUAL:
17994 Allow the deduced ARG to be more cv-qualified (by qualification
17995 conversion) than ARG.
17996 UNIFY_ALLOW_LESS_CV_QUAL:
17997 Allow the deduced ARG to be less cv-qualified than ARG.
17998 UNIFY_ALLOW_DERIVED:
17999 Allow the deduced ARG to be a template base class of ARG,
18000 or a pointer to a template base class of the type pointed to by
18001 ARG.
18002 UNIFY_ALLOW_INTEGER:
18003 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
18004 case for more information.
18005 UNIFY_ALLOW_OUTER_LEVEL:
18006 This is the outermost level of a deduction. Used to determine validity
18007 of qualification conversions. A valid qualification conversion must
18008 have const qualified pointers leading up to the inner type which
18009 requires additional CV quals, except at the outer level, where const
18010 is not required [conv.qual]. It would be normal to set this flag in
18011 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
18012 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
18013 This is the outermost level of a deduction, and PARM can be more CV
18014 qualified at this point.
18015 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
18016 This is the outermost level of a deduction, and PARM can be less CV
18017 qualified at this point. */
18019 static int
18022 {
18024 tree targ;
18025 tree tparm;
18028 /* I don't think this will do the right thing with respect to types.
18029 But the only case I've seen it in so far has been array bounds, where
18030 signedness is the only information lost, and I think that will be
18031 okay. */
18039 /* We can't deduce anything from this, but we might get all the
18040 template args from other function args. */
18043 /* If PARM uses template parameters, then we can't bail out here,
18044 even if ARG == PARM, since we won't record unifications for the
18045 template parameters. We might need them if we're trying to
18046 figure out which of two things is more specialized. */
18050 /* Handle init lists early, so the rest of the function can assume
18051 we're dealing with a type. */
18053 {
18058 /* Replace T with std::initializer_list<T> for deduction. */
18065 /* We can only deduce from an initializer list argument if the
18066 parameter is std::initializer_list or an array; otherwise this
18067 is a non-deduced context. */
18072 else
18073 {
18075 /* Deduction is defined in terms of a single type, so just punt
18076 on the (bizarre) std::initializer_list<T...>. */
18079 }
18082 {
18089 {
18093 /* It should only be possible to get here for a call. */
18095 elt_strict |= maybe_adjust_types_for_deduction
18098 }
18101 explain_p);
18102 }
18106 {
18107 /* Also deduce from the length of the initializer list. */
18114 }
18116 /* If the std::initializer_list<T> deduction worked, replace the
18117 deduced A with std::initializer_list<A>. */
18119 {
18124 }
18126 }
18128 /* Immediately reject some pairs that won't unify because of
18129 cv-qualification mismatches. */
18132 /* It is the elements of the array which hold the cv quals of an array
18133 type, and the elements might be template type parms. We'll check
18134 when we recurse. */
18136 /* We check the cv-qualifiers when unifying with template type
18137 parameters below. We want to allow ARG `const T' to unify with
18138 PARM `T' for example, when computing which of two templates
18139 is more specialized, for example. */
18153 {
18157 /* In a type which contains a nested-name-specifier, template
18158 argument values cannot be deduced for template parameters used
18159 within the nested-name-specifier. */
18171 /* The PARM is not one we're trying to unify. Just check
18172 to see if it matches ARG. */
18173 {
18178 else
18180 }
18187 /* Check for mixed types and values. */
18195 {
18196 /* ARG must be constructed from a template class or a template
18197 template parameter. */
18201 {
18203 /* An alias template name is never deduced. */
18208 tree parm_parms
18209 = DECL_INNERMOST_TEMPLATE_PARMS
18214 /* The resolution to DR150 makes clear that default
18215 arguments for an N-argument may not be used to bind T
18216 to a template template parameter with fewer than N
18217 parameters. It is not safe to permit the binding of
18218 default arguments as an extension, as that may change
18219 the meaning of a conforming program. Consider:
18221 struct Dense { static const unsigned int dim = 1; };
18223 template <template <typename> class View,
18224 typename Block>
18225 void operator+(float, View<Block> const&);
18227 template <typename Block,
18228 unsigned int Dim = Block::dim>
18229 struct Lvalue_proxy { operator float() const; };
18231 void
18232 test_1d (void) {
18233 Lvalue_proxy<Dense> p;
18234 float b;
18235 b + p;
18236 }
18238 Here, if Lvalue_proxy is permitted to bind to View, then
18239 the global operator+ will be used; if they are not, the
18240 Lvalue_proxy will be converted to float. */
18242 full_argvec,
18244 (explain_p
18245 ? tf_warning_or_error
18252 /* Deduce arguments T, i from TT<T> or TT<i>.
18253 We check each element of PARMVEC and ARGVEC individually
18254 rather than the whole TREE_VEC since they can have
18255 different number of elements. */
18262 /* Check if the parameters end in a pack, making them
18263 variadic. */
18269 /* If the template argument list of P contains a pack
18270 expansion that is not the last template argument, the
18271 entire template argument list is a non-deduced
18272 context. */
18281 {
18286 }
18291 DEDUCE_EXACT,
18294 }
18297 /* Fall through to deduce template name. */
18298 }
18302 {
18303 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
18305 /* Simple cases: Value already set, does match or doesn't. */
18310 }
18311 else
18312 {
18313 /* If PARM is `const T' and ARG is only `int', we don't have
18314 a match unless we are allowing additional qualification.
18315 If ARG is `const int' and PARM is just `T' that's OK;
18316 that binds `const int' to `T'. */
18321 /* Consider the case where ARG is `const volatile int' and
18322 PARM is `const T'. Then, T should be `volatile int'. */
18323 arg = cp_build_qualified_type_real
18328 /* Simple cases: Value already set, does match or doesn't. */
18334 /* Make sure that ARG is not a variable-sized array. (Note
18335 that were talking about variable-sized arrays (like
18336 `int[n]'), rather than arrays of unknown size (like
18337 `int[]').) We'll get very confused by such a type since
18338 the bound of the array is not constant, and therefore
18339 not mangleable. Besides, such types are not allowed in
18340 ISO C++, so we can do as we please here. We do allow
18341 them for 'auto' deduction, since that isn't ABI-exposed. */
18345 /* Strip typedefs as in convert_template_argument. */
18347 }
18349 /* If ARG is a parameter pack or an expansion, we cannot unify
18350 against it unless PARM is also a parameter pack. */
18355 /* If the argument deduction results is a METHOD_TYPE,
18356 then there is a problem.
18357 METHOD_TYPE doesn't map to any real C++ type the result of
18358 the deduction can not be of that type. */
18372 {
18373 /* The PARM is not one we're trying to unify. Just check
18374 to see if it matches ARG. */
18380 }
18386 {
18391 }
18393 /* [temp.deduct.type] If, in the declaration of a function template
18394 with a non-type template-parameter, the non-type
18395 template-parameter is used in an expression in the function
18396 parameter-list and, if the corresponding template-argument is
18397 deduced, the template-argument type shall match the type of the
18398 template-parameter exactly, except that a template-argument
18399 deduced from an array bound may be of any integral type.
18400 The non-type parameter might use already deduced type parameters. */
18403 /* Template-parameter dependent expression. Just accept it for now.
18404 It will later be processed in convert_template_argument. */
18405 ;
18410 /* Convert the ARG to the type of PARM; the deduced non-type
18411 template argument must exactly match the types of the
18412 corresponding parameter. */
18415 /* We haven't deduced the type of this parameter yet. Try again
18416 later. */
18418 else
18421 /* If ARG is a parameter pack or an expansion, we cannot unify
18422 against it unless PARM is also a parameter pack. */
18432 {
18433 /* A pointer-to-member constant can be unified only with
18434 another constant. */
18438 /* Just unify the class member. It would be useless (and possibly
18439 wrong, depending on the strict flags) to unify also
18440 PTRMEM_CST_CLASS, because we want to be sure that both parm and
18441 arg refer to the same variable, even if through different
18442 classes. For instance:
18444 struct A { int x; };
18445 struct B : A { };
18447 Unification of &A::x and &B::x must succeed. */
18450 }
18453 {
18457 /* [temp.deduct.call]
18459 A can be another pointer or pointer to member type that can
18460 be converted to the deduced A via a qualification
18461 conversion (_conv.qual_).
18463 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
18464 This will allow for additional cv-qualification of the
18465 pointed-to types if appropriate. */
18468 /* The derived-to-base conversion only persists through one
18469 level of pointers. */
18474 }
18506 /* We have already checked cv-qualification at the top of the
18507 function. */
18511 /* As far as unification is concerned, this wins. Later checks
18512 will invalidate it if necessary. */
18515 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
18516 /* Type INTEGER_CST can come from ordinary constant template args. */
18528 {
18538 /* Check for pack expansions in the parameters. */
18540 {
18542 {
18544 /* We can unify against something with a trailing
18545 parameter pack. */
18547 else
18548 /* [temp.deduct.type]/9: If the template argument list of
18549 P contains a pack expansion that is not the last
18550 template argument, the entire template argument list
18551 is a non-deduced context. */
18553 }
18554 }
18556 /* If we don't have enough arguments to satisfy the parameters
18557 (not counting the pack expression at the end), or we have
18558 too many arguments for a parameter list that doesn't end in
18559 a pack expression, we can't unify. */
18565 /* Unify all of the parameters that precede the (optional)
18566 pack expression. */
18568 {
18573 }
18576 DEDUCE_EXACT,
18579 }
18587 {
18595 }
18600 {
18604 {
18605 /* First, we try to unify the PARM and ARG directly. */
18610 {
18611 /* Fallback to the special case allowed in
18612 [temp.deduct.call]:
18614 If P is a class, and P has the form
18615 template-id, then A can be a derived class of
18616 the deduced A. Likewise, if P is a pointer to
18617 a class of the form template-id, A can be a
18618 pointer to a derived class pointed to by the
18619 deduced A. */
18626 }
18627 }
18631 /* Perhaps PARM is something like S<U> and ARG is S<int>.
18632 Then, we should unify `int' and `U'. */
18634 else
18635 /* There's no chance of unification succeeding. */
18640 }
18647 {
18650 tree a;
18656 /* CV qualifications for methods can never be deduced, they must
18657 match exactly. We need to check them explicitly here,
18658 because type_unification_real treats them as any other
18659 cv-qualified parameter. */
18661 && (!check_cv_quals_for_unify
18681 }
18684 /* Unify a pointer to member with a pointer to member function, which
18685 deduces the type of the member as a function type. */
18687 {
18688 /* Check top-level cv qualifiers */
18696 /* Determine the type of the function we are unifying against. */
18700 }
18719 /* Matched cases are handled by the ARG == PARM test above. */
18723 /* A non-type template parameter that is a variable should be a
18724 an integral constant, in which case, it whould have been
18725 folded into its (constant) value. So we should not be getting
18726 a variable here. */
18737 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
18738 or UNDERLYING_TYPE nodes. */
18742 /* Unification fails if we hit an error node. */
18747 {
18752 }
18753 /* FALLTHRU */
18756 /* An unresolved overload is a nondeduced context. */
18761 /* We must be looking at an expression. This can happen with
18762 something like:
18764 template <int I>
18765 void foo(S<I>, S<I + 2>);
18767 This is a "nondeduced context":
18769 [deduct.type]
18771 The nondeduced contexts are:
18773 --A type that is a template-id in which one or more of
18774 the template-arguments is an expression that references
18775 a template-parameter.
18777 In these cases, we assume deduction succeeded, but don't
18778 actually infer any unifications. */
18783 else
18785 }
18786 }
18787 #undef RECUR_AND_CHECK_FAILURE
18788 \f
18789 /* Note that DECL can be defined in this translation unit, if
18790 required. */
18792 static void
18794 {
18795 tree clone;
18799 }
18801 /* Called if RESULT is explicitly instantiated, or is a member of an
18802 explicitly instantiated class. */
18804 void
18806 {
18809 /* If this entity has already been written out, it's too late to
18810 make any modifications. */
18814 /* For anonymous namespace we don't need to do anything. */
18816 {
18819 }
18822 /* The TREE_PUBLIC flag for function declarations will have been
18823 set correctly by tsubst. */
18826 /* This might have been set by an earlier implicit instantiation. */
18831 else
18832 {
18835 /* Always make artificials weak. */
18838 /* For WIN32 we also want to put explicit instantiations in
18839 linkonce sections. */
18842 }
18844 /* If EXTERN_P, then this function will not be emitted -- unless
18845 followed by an explicit instantiation, at which point its linkage
18846 will be adjusted. If !EXTERN_P, then this function will be
18847 emitted here. In neither circumstance do we want
18848 import_export_decl to adjust the linkage. */
18850 }
18852 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
18853 important template arguments. If any are missing, we check whether
18854 they're important by using error_mark_node for substituting into any
18855 args that were used for partial ordering (the ones between ARGS and END)
18856 and seeing if it bubbles up. */
18858 static bool
18860 {
18865 {
18868 }
18870 {
18874 }
18876 }
18878 /* Given two function templates PAT1 and PAT2, return:
18880 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
18881 -1 if PAT2 is more specialized than PAT1.
18882 0 if neither is more specialized.
18884 LEN indicates the number of parameters we should consider
18885 (defaulted parameters should not be considered).
18887 The 1998 std underspecified function template partial ordering, and
18888 DR214 addresses the issue. We take pairs of arguments, one from
18889 each of the templates, and deduce them against each other. One of
18890 the templates will be more specialized if all the *other*
18891 template's arguments deduce against its arguments and at least one
18892 of its arguments *does* *not* deduce against the other template's
18893 corresponding argument. Deduction is done as for class templates.
18894 The arguments used in deduction have reference and top level cv
18895 qualifiers removed. Iff both arguments were originally reference
18896 types *and* deduction succeeds in both directions, an lvalue reference
18897 wins against an rvalue reference and otherwise the template
18898 with the more cv-qualified argument wins for that pairing (if
18899 neither is more cv-qualified, they both are equal). Unlike regular
18900 deduction, after all the arguments have been deduced in this way,
18901 we do *not* verify the deduced template argument values can be
18902 substituted into non-deduced contexts.
18904 The logic can be a bit confusing here, because we look at deduce1 and
18905 targs1 to see if pat2 is at least as specialized, and vice versa; if we
18906 can find template arguments for pat1 to make arg1 look like arg2, that
18907 means that arg2 is at least as specialized as arg1. */
18909 int
18911 {
18924 /* Remove the this parameter from non-static member functions. If
18925 one is a non-static member function and the other is not a static
18926 member function, remove the first parameter from that function
18927 also. This situation occurs for operator functions where we
18928 locate both a member function (with this pointer) and non-member
18929 operator (with explicit first operand). */
18931 {
18936 }
18938 {
18941 {
18942 len--;
18944 }
18945 }
18947 /* If only one is a conversion operator, they are unordered. */
18951 /* Consider the return type for a conversion function */
18953 {
18956 len++;
18957 }
18959 processing_template_decl++;
18965 /* Stop when an ellipsis is seen. */
18967 {
18978 {
18979 /* When both arguments are pack expansions, we need only
18980 unify the patterns themselves. */
18984 /* This is the last comparison we need to do. */
18986 }
18989 {
18993 }
18996 {
19000 }
19006 {
19012 /* Setup the parameter vector, which contains only ARG1. */
19015 /* Setup the argument vector, which contains the remaining
19016 arguments. */
19025 /* We cannot deduce in the other direction, because ARG1 is
19026 a pack expansion but ARG2 is not. */
19028 }
19030 {
19036 /* Setup the parameter vector, which contains only ARG1. */
19039 /* Setup the argument vector, which contains the remaining
19040 arguments. */
19049 /* We cannot deduce in the other direction, because ARG2 is
19050 a pack expansion but ARG1 is not.*/
19052 }
19054 else
19055 {
19056 /* The normal case, where neither argument is a pack
19057 expansion. */
19064 }
19066 /* If we couldn't deduce arguments for tparms1 to make arg1 match
19067 arg2, then arg2 is not as specialized as arg1. */
19073 /* "If, for a given type, deduction succeeds in both directions
19074 (i.e., the types are identical after the transformations above)
19075 and both P and A were reference types (before being replaced with
19076 the type referred to above):
19077 - if the type from the argument template was an lvalue reference and
19078 the type from the parameter template was not, the argument type is
19079 considered to be more specialized than the other; otherwise,
19080 - if the type from the argument template is more cv-qualified
19081 than the type from the parameter template (as described above),
19082 the argument type is considered to be more specialized than the other;
19083 otherwise,
19084 - neither type is more specialized than the other." */
19087 {
19089 {
19092 else
19094 }
19096 {
19101 }
19102 }
19105 /* We've failed to deduce something in either direction.
19106 These must be unordered. */
19111 /* We have already processed all of the arguments in our
19112 handing of the pack expansion type. */
19117 }
19119 /* "In most cases, all template parameters must have values in order for
19120 deduction to succeed, but for partial ordering purposes a template
19121 parameter may remain without a value provided it is not used in the
19122 types being used for partial ordering."
19124 Thus, if we are missing any of the targs1 we need to substitute into
19125 origs1, then pat2 is not as specialized as pat1. This can happen when
19126 there is a nondeduced context. */
19132 processing_template_decl--;
19134 /* All things being equal, if the next argument is a pack expansion
19135 for one function but not for the other, prefer the
19136 non-variadic function. FIXME this is bogus; see c++/41958. */
19140 {
19143 }
19149 else
19151 }
19153 /* Determine which of two partial specializations of TMPL is more
19154 specialized.
19156 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
19157 to the first partial specialization. The TREE_PURPOSE is the
19158 innermost set of template parameters for the partial
19159 specialization. PAT2 is similar, but for the second template.
19161 Return 1 if the first partial specialization is more specialized;
19162 -1 if the second is more specialized; 0 if neither is more
19163 specialized.
19165 See [temp.class.order] for information about determining which of
19166 two templates is more specialized. */
19168 static int
19170 {
19171 tree targs;
19182 /* Just like what happens for functions, if we are ordering between
19183 different template specializations, we may encounter dependent
19184 types in the arguments, and we need our dependency check functions
19185 to behave correctly. */
19189 {
19192 }
19196 {
19199 }
19202 /* In the case of a tie where at least one of the templates
19203 has a parameter pack at the end, the template with the most
19204 non-packed parameters wins. */
19206 && any_deductions
19209 {
19215 /* We don't count the pack expansion at the end. */
19225 }
19228 }
19230 /* Return the template arguments that will produce the function signature
19231 DECL from the function template FN, with the explicit template
19232 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
19233 also match. Return NULL_TREE if no satisfactory arguments could be
19234 found. */
19236 static tree
19238 {
19242 tree decl_arg_types;
19245 tree arg;
19249 /* Never do unification on the 'this' parameter. */
19270 }
19272 /* Return the innermost template arguments that, when applied to a partial
19273 specialization of TMPL whose innermost template parameters are
19274 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
19275 ARGS.
19277 For example, suppose we have:
19279 template <class T, class U> struct S {};
19280 template <class T> struct S<T*, int> {};
19282 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
19283 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
19284 int}. The resulting vector will be {double}, indicating that `T'
19285 is bound to `double'. */
19287 static tree
19289 {
19291 tree deduced_args;
19292 tree innermost_deduced_args;
19296 {
19300 innermost_deduced_args);
19301 }
19302 else
19315 /* Verify that nondeduced template arguments agree with the type
19316 obtained from argument deduction.
19318 For example:
19320 struct A { typedef int X; };
19321 template <class T, class U> struct C {};
19322 template <class T> struct C<T, typename T::X> {};
19324 Then with the instantiation `C<A, int>', we can deduce that
19325 `T' is `A' but unify () does not check whether `typename T::X'
19326 is `int'. */
19332 /* We only need to check the innermost arguments; the other
19333 arguments will always agree. */
19338 /* Now that we have bindings for all of the template arguments,
19339 ensure that the arguments deduced for the template template
19340 parameters have compatible template parameter lists. See the use
19341 of template_template_parm_bindings_ok_p in fn_type_unification
19342 for more information. */
19347 }
19349 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
19350 Return the TREE_LIST node with the most specialized template, if
19351 any. If there is no most specialized template, the error_mark_node
19352 is returned.
19354 Note that this function does not look at, or modify, the
19355 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
19356 returned is one of the elements of INSTANTIATIONS, callers may
19357 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
19358 and retrieve it from the value returned. */
19360 tree
19362 {
19369 {
19375 fate--;
19380 fate++;
19385 {
19386 /* Equally specialized, move to next function. If there
19387 is no next function, nothing's most specialized. */
19392 }
19393 }
19396 /* Now verify that champ is better than everything earlier in the
19397 instantiation list. */
19405 {
19408 }
19410 processing_template_decl--;
19416 }
19418 /* If DECL is a specialization of some template, return the most
19419 general such template. Otherwise, returns NULL_TREE.
19421 For example, given:
19423 template <class T> struct S { template <class U> void f(U); };
19425 if TMPL is `template <class U> void S<int>::f(U)' this will return
19426 the full template. This function will not trace past partial
19427 specializations, however. For example, given in addition:
19429 template <class T> struct S<T*> { template <class U> void f(U); };
19431 if TMPL is `template <class U> void S<int*>::f(U)' this will return
19432 `template <class T> template <class U> S<T*>::f(U)'. */
19434 tree
19436 {
19438 {
19441 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
19442 template friend, or a FIELD_DECL for a capture pack. */
19445 }
19447 /* Look for more and more general templates. */
19449 {
19450 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
19451 (See cp-tree.h for details.) */
19460 /* Stop if we run into an explicitly specialized class template. */
19467 }
19470 }
19472 /* Return the most specialized of the template partial specializations
19473 which can produce TARGET, a specialization of some class or variable
19474 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
19475 a TEMPLATE_DECL node corresponding to the partial specialization, while
19476 the TREE_PURPOSE is the set of template arguments that must be
19477 substituted into the template pattern in order to generate TARGET.
19479 If the choice of partial specialization is ambiguous, a diagnostic
19480 is issued, and the error_mark_node is returned. If there are no
19481 partial specializations matching TARGET, then NULL_TREE is
19482 returned, indicating that the primary template should be used. */
19484 static tree
19486 {
19488 tree t;
19489 tree champ;
19496 {
19500 }
19502 {
19505 }
19507 {
19511 }
19512 else
19517 /* For determining which partial specialization to use, only the
19518 innermost args are interesting. */
19520 {
19523 }
19526 {
19527 tree partial_spec_args;
19528 tree spec_args;
19536 {
19537 /* Discard the outer levels of args, and then substitute in the
19538 template args from the enclosing class. */
19540 partial_spec_args = tsubst_template_args
19543 /* And the same for the partial specialization TEMPLATE_DECL. */
19545 }
19547 partial_spec_args =
19549 partial_spec_args,
19563 partial_spec_args,
19564 args);
19566 {
19571 }
19572 }
19582 {
19585 ;
19586 else
19587 {
19589 {
19592 {
19595 }
19596 }
19598 }
19599 }
19603 {
19606 {
19609 }
19610 }
19613 {
19620 else
19624 {
19629 }
19632 }
19635 }
19637 /* Explicitly instantiate DECL. */
19639 void
19641 {
19646 /* An error occurred, for which grokdeclarator has already issued
19647 an appropriate message. */
19650 {
19653 }
19659 {
19660 /* There is an asymmetry here in the way VAR_DECLs and
19661 FUNCTION_DECLs are handled by grokdeclarator. In the case of
19662 the latter, the DECL we get back will be marked as a
19663 template instantiation, and the appropriate
19664 DECL_TEMPLATE_INFO will be set up. This does not happen for
19665 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
19666 should handle VAR_DECLs as it currently handles
19667 FUNCTION_DECLs. */
19669 {
19672 }
19675 {
19678 }
19680 {
19685 }
19686 }
19688 {
19691 }
19692 else
19695 /* Check for various error cases. Note that if the explicit
19696 instantiation is valid the RESULT will currently be marked as an
19697 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
19698 until we get here. */
19701 {
19702 /* DR 259 [temp.spec].
19704 Both an explicit instantiation and a declaration of an explicit
19705 specialization shall not appear in a program unless the explicit
19706 instantiation follows a declaration of the explicit specialization.
19708 For a given set of template parameters, if an explicit
19709 instantiation of a template appears after a declaration of an
19710 explicit specialization for that template, the explicit
19711 instantiation has no effect. */
19713 }
19715 {
19716 /* [temp.spec]
19718 No program shall explicitly instantiate any template more
19719 than once.
19721 We check DECL_NOT_REALLY_EXTERN so as not to complain when
19722 the first instantiation was `extern' and the second is not,
19723 and EXTERN_P for the opposite case. */
19726 /* If an "extern" explicit instantiation follows an ordinary
19727 explicit instantiation, the template is instantiated. */
19730 }
19732 {
19735 }
19737 {
19740 }
19743 ;
19745 {
19748 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
19751 }
19752 else
19760 }
19762 static void
19764 {
19770 {
19773 }
19774 }
19776 /* Called from do_type_instantiation through binding_table_foreach to
19777 do recursive instantiation for the type bound in ENTRY. */
19778 static void
19780 {
19786 }
19788 /* Called from do_type_instantiation to instantiate a member
19789 (a member function or a static member variable) of an
19790 explicitly instantiated class template. */
19791 static void
19793 {
19798 }
19800 /* Perform an explicit instantiation of template class T. STORAGE, if
19801 non-null, is the RID for extern, inline or static. COMPLAIN is
19802 nonzero if this is called from the parser, zero if called recursively,
19803 since the standard is unclear (as detailed below). */
19805 void
19807 {
19817 {
19818 tree tmpl =
19822 else
19825 }
19830 {
19833 t);
19835 }
19838 {
19840 {
19842 {
19845 "ISO C++ 1998 forbids the use of %<extern%> on "
19847 }
19848 else
19850 "ISO C++ forbids the use of %qE"
19852 }
19860 else
19861 {
19863 storage);
19865 }
19866 }
19869 {
19870 /* DR 259 [temp.spec].
19872 Both an explicit instantiation and a declaration of an explicit
19873 specialization shall not appear in a program unless the explicit
19874 instantiation follows a declaration of the explicit specialization.
19876 For a given set of template parameters, if an explicit
19877 instantiation of a template appears after a declaration of an
19878 explicit specialization for that template, the explicit
19879 instantiation has no effect. */
19881 }
19883 {
19884 /* [temp.spec]
19886 No program shall explicitly instantiate any template more
19887 than once.
19889 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
19890 instantiation was `extern'. If EXTERN_P then the second is.
19891 These cases are OK. */
19898 /* If we've already instantiated the template, just return now. */
19901 }
19909 {
19910 tree tmp;
19912 /* In contrast to implicit instantiation, where only the
19913 declarations, and not the definitions, of members are
19914 instantiated, we have here:
19916 [temp.explicit]
19918 The explicit instantiation of a class template specialization
19919 implies the instantiation of all of its members not
19920 previously explicitly specialized in the translation unit
19921 containing the explicit instantiation.
19923 Of course, we can't instantiate member template classes, since
19924 we don't have any arguments for them. Note that the standard
19925 is unclear on whether the instantiation of the members are
19926 *explicit* instantiations or not. However, the most natural
19927 interpretation is that it should be an explicit instantiation. */
19942 }
19943 }
19945 /* Given a function DECL, which is a specialization of TMPL, modify
19946 DECL to be a re-instantiation of TMPL with the same template
19947 arguments. TMPL should be the template into which tsubst'ing
19948 should occur for DECL, not the most general template.
19950 One reason for doing this is a scenario like this:
19952 template <class T>
19953 void f(const T&, int i);
19955 void g() { f(3, 7); }
19957 template <class T>
19958 void f(const T& t, const int i) { }
19960 Note that when the template is first instantiated, with
19961 instantiate_template, the resulting DECL will have no name for the
19962 first parameter, and the wrong type for the second. So, when we go
19963 to instantiate the DECL, we regenerate it. */
19965 static void
19967 {
19968 /* The arguments used to instantiate DECL, from the most general
19969 template. */
19970 tree args;
19971 tree code_pattern;
19976 /* Make sure that we can see identifiers, and compute access
19977 correctly. */
19981 {
19982 tree decl_parm;
19983 tree pattern_parm;
19984 tree specs;
19998 specs);
20000 /* Merge parameter declarations. */
20003 pattern_parm
20007 {
20008 tree parm_type;
20009 tree attributes;
20014 NULL_TREE);
20020 {
20023 }
20026 }
20027 /* Merge any parameters that match with the function parameter
20028 pack. */
20030 {
20032 tree expanded_types;
20033 /* Expand the TYPE_PACK_EXPANSION that provides the types for
20034 the parameters in this function parameter pack. */
20039 {
20040 tree parm_type;
20041 tree attributes;
20044 /* Rename the parameter to include the index. */
20053 {
20056 }
20058 }
20059 }
20060 /* Merge additional specifiers from the CODE_PATTERN. */
20064 }
20066 {
20074 }
20075 else
20079 }
20081 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
20082 substituted to get DECL. */
20084 tree
20086 {
20089 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
20090 for the instantiation. This is not always the most general
20091 template. Consider, for example:
20093 template <class T>
20094 struct S { template <class U> void f();
20095 template <> void f<int>(); };
20097 and an instantiation of S<double>::f<int>. We want TD to be the
20098 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
20100 more general template. */
20102 /* We must also deal with friend templates. Given:
20104 template <class T> struct S {
20105 template <class U> friend void f() {};
20106 };
20108 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
20109 so far as the language is concerned, but that's still
20110 where we get the pattern for the instantiation from. On
20111 other hand, if the definition comes outside the class, say:
20113 template <class T> struct S {
20114 template <class U> friend void f();
20115 };
20116 template <class U> friend void f() {}
20118 we don't need to look any further. That's what the check for
20119 DECL_INITIAL is for. */
20123 {
20124 /* The present template, TD, should not be a definition. If it
20125 were a definition, we should be using it! Note that we
20126 cannot restructure the loop to just keep going until we find
20127 a template with a definition, since that might go too far if
20128 a specialization was declared, but not defined. */
20130 /* Fetch the more general template. */
20132 }
20135 }
20137 /* Returns true if we need to instantiate this template instance even if we
20138 know we aren't going to emit it.. */
20140 bool
20142 {
20143 /* We always instantiate inline functions so that we can inline them. An
20144 explicit instantiation declaration prohibits implicit instantiation of
20145 non-inline functions. With high levels of optimization, we would
20146 normally inline non-inline functions -- but we're not allowed to do
20147 that for "extern template" functions. Therefore, we check
20148 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
20152 /* And we need to instantiate static data members so that
20153 their initializers are available in integral constant
20154 expressions. */
20157 }
20159 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
20160 instantiate it now, modifying TREE_TYPE (fn). */
20162 void
20164 {
20167 /* Don't instantiate a noexcept-specification from template context. */
20182 {
20186 {
20201 }
20202 else
20206 }
20209 {
20212 else
20214 }
20215 }
20217 /* Produce the definition of D, a _DECL generated from a template. If
20218 DEFER_OK is nonzero, then we don't have to actually do the
20219 instantiation now; we just have to do it sometime. Normally it is
20220 an error if this is an explicit instantiation but D is undefined.
20221 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
20222 explicitly instantiated class template. */
20224 tree
20227 {
20229 tree gen_args;
20230 tree args;
20231 tree td;
20232 tree code_pattern;
20233 tree spec;
20234 tree gen_tmpl;
20241 tree fn_context;
20244 /* This function should only be used to instantiate templates for
20245 functions and static member variables. */
20248 /* Variables are never deferred; if instantiation is required, they
20249 are instantiated right away. That allows for better code in the
20250 case that an expression refers to the value of the variable --
20251 if the variable has a constant value the referring expression can
20252 take advantage of that fact. */
20257 /* Don't instantiate cloned functions. Instead, instantiate the
20258 functions they cloned. */
20266 /* D has already been instantiated or explicitly specialized, so
20267 there's nothing for us to do here.
20269 It might seem reasonable to check whether or not D is an explicit
20270 instantiation, and, if so, stop here. But when an explicit
20271 instantiation is deferred until the end of the compilation,
20272 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
20273 the instantiation. */
20276 /* Check to see whether we know that this template will be
20277 instantiated in some other file, as with "extern template"
20278 extension. */
20281 /* In general, we do not instantiate such templates. */
20289 /* We should already have the extra args. */
20292 /* And what's in the hash table should match D. */
20296 /* This needs to happen before any tsubsting. */
20302 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
20303 for the instantiation. */
20307 /* We should never be trying to instantiate a member of a class
20308 template or partial specialization. */
20313 /* In the case of a friend template whose definition is provided
20314 outside the class, we may have too many arguments. Drop the
20315 ones we don't need. The same is true for specializations. */
20316 args = get_innermost_template_args
20318 else
20322 {
20327 }
20328 else
20329 {
20332 }
20334 /* We may be in the middle of deferred access check. Disable it now. */
20337 /* Unless an explicit instantiation directive has already determined
20338 the linkage of D, remember that a definition is available for
20339 this entity. */
20349 /* If D is a member of an explicitly instantiated class template,
20350 and no definition is available, treat it like an implicit
20351 instantiation. */
20354 {
20355 /* Leave linkage flags alone on instantiations with anonymous
20356 visibility. */
20358 {
20361 }
20363 }
20365 /* Defer all other templates, unless we have been explicitly
20366 forbidden from doing so. */
20368 template. */
20369 ! pattern_defined
20370 /* If it's OK to postpone instantiation, do so. */
20371 || defer_ok
20372 /* If this is a static data member that will be defined
20373 elsewhere, we don't want to instantiate the entire data
20374 member, but we do want to instantiate the initializer so that
20375 we can substitute that elsewhere. */
20377 /* Handle here a deleted function too, avoid generating
20378 its body (c++/61080). */
20380 {
20381 /* The definition of the static data member is now required so
20382 we must substitute the initializer. */
20386 {
20387 tree ns;
20388 tree init;
20397 args,
20400 /* If instantiating the initializer involved instantiating this
20401 again, don't call cp_finish_decl twice. */
20403 {
20404 /* Make sure the initializer is still constant, in case of
20405 circular dependency (template/instantiate6.C). */
20406 const_init
20410 LOOKUP_ONLYCONVERTING);
20411 }
20415 }
20417 /* We restore the source position here because it's used by
20418 add_pending_template. */
20424 /* [temp.explicit]
20426 The definition of a non-exported function template, a
20427 non-exported member function template, or a non-exported
20428 member function or static data member of a class template
20429 shall be present in every translation unit in which it is
20430 explicitly instantiated. */
20434 /* If we're in unevaluated context, we just wanted to get the
20435 constant value; this isn't an odr use, so don't queue
20436 a full instantiation. */
20439 /* ??? Historically, we have instantiated inline functions, even
20440 when marked as "extern template". */
20444 }
20445 /* Tell the repository that D is available in this translation unit
20446 -- and see if it is supposed to be instantiated here. */
20448 {
20449 /* In a PCH file, despite the fact that the repository hasn't
20450 requested instantiation in the PCH it is still possible that
20451 an instantiation will be required in a file that includes the
20452 PCH. */
20455 /* Instantiate inline functions so that the inliner can do its
20456 job, even though we'll not be emitting a copy of this
20457 function. */
20460 }
20466 else
20467 {
20472 }
20474 /* Mark D as instantiated so that recursive calls to
20475 instantiate_decl do not try to instantiate it again. */
20478 /* Regenerate the declaration in case the template has been modified
20479 by a subsequent redeclaration. */
20482 /* We already set the file and line above. Reset them now in case
20483 they changed as a result of calling regenerate_decl_from_template. */
20487 {
20488 tree init;
20491 /* Clear out DECL_RTL; whatever was there before may not be right
20492 since we've reset the type of the declaration. */
20496 /* The initializer is placed in DECL_INITIAL by
20497 regenerate_decl_from_template so we don't need to
20498 push/pop_access_scope again here. Pull it out so that
20499 cp_finish_decl can process it. */
20504 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
20505 initializer. That function will defer actual emission until
20506 we have a chance to determine linkage. */
20509 /* Enter the scope of D so that access-checking works correctly. */
20522 }
20526 {
20528 tree subst_decl;
20529 tree tmpl_parm;
20530 tree spec_parm;
20533 /* Save away the current list, in case we are instantiating one
20534 template from within the body of another. */
20537 /* Set up the list of local specializations. */
20540 /* Set up context. */
20544 else
20547 /* Some typedefs referenced from within the template code need to be
20548 access checked at template instantiation time, i.e now. These
20549 types were added to the template at parsing time. Let's get those
20550 and perform the access checks then. */
20552 gen_args);
20554 /* Create substitution entries for the parameters. */
20559 {
20563 }
20565 {
20567 {
20570 }
20571 else
20572 {
20573 /* Register the (value) argument pack as a specialization of
20574 TMPL_PARM, then move on. */
20577 }
20578 }
20581 /* Substitute into the body of the function. */
20585 else
20586 {
20591 /* Set the current input_location to the end of the function
20592 so that finish_function knows where we are. */
20593 input_location
20596 /* Remember if we saw an infinite loop in the template. */
20597 current_function_infinite_loop
20599 }
20601 /* We don't need the local specializations any more. */
20605 /* Finish the function. */
20609 else
20610 {
20613 }
20617 }
20619 /* We're not deferring instantiation any more. */
20627 out:
20637 }
20639 /* Run through the list of templates that we wish we could
20640 instantiate, and instantiate any we can. RETRIES is the
20641 number of times we retry pending template instantiation. */
20643 void
20645 {
20649 /* Instantiating templates may trigger vtable generation. This in turn
20650 may require further template instantiations. We place a limit here
20651 to avoid infinite loop. */
20653 {
20657 "template instantiation depth exceeds maximum of %d"
20658 " instantiating %q+D, possibly from virtual table generation"
20662 /* Pretend that we defined it. */
20665 }
20667 do
20668 {
20673 {
20678 {
20679 tree fn;
20682 {
20686 fn;
20694 }
20697 }
20698 else
20699 {
20702 {
20703 instantiation
20709 }
20713 }
20716 /* If INSTANTIATION has been instantiated, then we don't
20717 need to consider it again in the future. */
20719 else
20720 {
20723 }
20726 }
20728 }
20732 }
20734 /* Substitute ARGVEC into T, which is a list of initializers for
20735 either base class or a non-static data member. The TREE_PURPOSEs
20736 are DECLs, and the TREE_VALUEs are the initializer values. Used by
20737 instantiate_decl. */
20739 static tree
20741 {
20745 {
20746 tree decl;
20747 tree init;
20753 {
20754 tree expr;
20755 tree arg;
20757 /* Expand the base class expansion type into separate base
20758 classes. */
20760 tf_warning_or_error,
20761 NULL_TREE);
20765 /* We'll be building separate TREE_LISTs of arguments for
20766 each base. */
20772 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
20773 expand each argument in the TREE_VALUE of t. */
20780 /* VOID_TYPE_NODE is used to indicate
20781 value-initialization. */
20782 {
20785 }
20786 else
20787 {
20788 /* Substitute parameter packs into each argument in the
20789 TREE_LIST. */
20792 {
20793 tree expanded_exprs;
20795 /* Expand the argument. */
20797 expanded_exprs
20799 tf_warning_or_error,
20800 NULL_TREE);
20804 /* Prepend each of the expanded expressions to the
20805 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
20807 {
20812 }
20813 }
20816 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
20817 since we built them backwards. */
20819 {
20822 }
20823 }
20824 }
20827 {
20829 {
20833 }
20834 else
20835 {
20836 tree tmp;
20851 /* If we had an initializer but it instantiated to nothing,
20852 value-initialize the object. This will only occur when
20853 the initializer was a pack expansion where the parameter
20854 packs used in that expansion were of length zero. */
20857 }
20860 {
20864 }
20865 }
20866 }
20868 }
20870 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
20872 static void
20874 {
20879 else
20881 }
20883 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
20884 is the instantiation (which should have been created with
20885 start_enum) and ARGS are the template arguments to use. */
20887 static void
20889 {
20890 tree e;
20896 {
20897 tree value;
20898 tree decl;
20901 /* Note that in a template enum, the TREE_VALUE is the
20902 CONST_DECL, not the corresponding INTEGER_CST. */
20907 /* Give this enumeration constant the correct access. */
20910 /* Actually build the enumerator itself. */
20911 build_enumerator
20913 }
20923 }
20925 /* DECL is a FUNCTION_DECL that is a template specialization. Return
20926 its type -- but without substituting the innermost set of template
20927 arguments. So, innermost set of template parameters will appear in
20928 the type. */
20930 tree
20932 {
20933 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
20935 }
20937 /* Return truthvalue if we're processing a template different from
20938 the last one involved in diagnostics. */
20939 bool
20941 {
20943 }
20945 /* Remember current template involved in diagnostics. */
20946 void
20948 {
20950 }
20954 {
20956 }
20958 /* Return TRUE if current_function_decl is being instantiated, false
20959 otherwise. */
20961 bool
20963 {
20966 }
20968 /* [temp.param] Check that template non-type parm TYPE is of an allowable
20969 type. Return zero for ok, nonzero for disallowed. Issue error and
20970 warning messages under control of COMPLAIN. */
20972 static int
20974 {
20991 {
20994 else
20996 type);
20997 }
20999 }
21001 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
21002 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
21004 static bool
21006 {
21007 tree scope;
21009 /* [temp.dep.type]
21011 A type is dependent if it is:
21013 -- a template parameter. Template template parameters are types
21014 for us (since TYPE_P holds true for them) so we handle
21015 them here. */
21019 /* -- a qualified-id with a nested-name-specifier which contains a
21020 class-name that names a dependent type or whose unqualified-id
21021 names a dependent type. */
21025 /* An alias template specialization can be dependent even if the
21026 resulting type is not. */
21030 /* -- a cv-qualified type where the cv-unqualified type is
21031 dependent.
21032 No code is necessary for this bullet; the code below handles
21033 cv-qualified types, and we don't want to strip aliases with
21034 TYPE_MAIN_VARIANT because of DR 1558. */
21035 /* -- a compound type constructed from any dependent type. */
21045 {
21046 tree arg_type;
21051 arg_type;
21056 }
21057 /* -- an array type constructed from any dependent type or whose
21058 size is specified by a constant expression that is
21059 value-dependent.
21061 We checked for type- and value-dependence of the bounds in
21062 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
21064 {
21069 }
21071 /* -- a template-id in which either the template name is a template
21072 parameter ... */
21075 /* ... or any of the template arguments is a dependent type or
21076 an expression that is type-dependent or value-dependent. */
21078 && (any_dependent_template_arguments_p
21082 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
21083 dependent; if the argument of the `typeof' expression is not
21084 type-dependent, then it should already been have resolved. */
21090 /* A template argument pack is dependent if any of its packed
21091 arguments are. */
21093 {
21099 }
21101 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
21102 be template parameters. */
21106 /* The standard does not specifically mention types that are local
21107 to template functions or local classes, but they should be
21108 considered dependent too. For example:
21110 template <int I> void f() {
21111 enum E { a = I };
21112 S<sizeof (E)> s;
21113 }
21115 The size of `E' cannot be known until the value of `I' has been
21116 determined. Therefore, `E' must be considered dependent. */
21120 /* Don't use type_dependent_expression_p here, as it can lead
21121 to infinite recursion trying to determine whether a lambda
21122 nested in a lambda is dependent (c++/47687). */
21126 && (any_dependent_template_arguments_p
21130 /* Other types are non-dependent. */
21132 }
21134 /* Returns TRUE if TYPE is dependent, in the sense of
21135 [temp.dep.type]. Note that a NULL type is considered dependent. */
21137 bool
21139 {
21140 /* If there are no template parameters in scope, then there can't be
21141 any dependent types. */
21143 {
21144 /* If we are not processing a template, then nobody should be
21145 providing us with a dependent type. */
21149 }
21151 /* If the type is NULL, we have not computed a type for the entity
21152 in question; in that case, the type is dependent. */
21156 /* Erroneous types can be considered non-dependent. */
21160 /* If we have not already computed the appropriate value for TYPE,
21161 do so now. */
21163 {
21166 }
21169 }
21171 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
21172 lookup. In other words, a dependent type that is not the current
21173 instantiation. */
21175 bool
21177 {
21180 }
21182 /* T is a SCOPE_REF; return whether we need to consider it
21183 instantiation-dependent so that we can check access at instantiation
21184 time even though we know which member it resolves to. */
21186 static bool
21188 {
21194 else
21196 }
21198 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
21199 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
21200 expression. */
21202 /* Note that this predicate is not appropriate for general expressions;
21203 only constant expressions (that satisfy potential_constant_expression)
21204 can be tested for value dependence. */
21206 bool
21208 {
21212 /* A name declared with a dependent type. */
21217 {
21219 /* A name that has not been looked up -- must be dependent. */
21223 /* A non-type template parm. */
21227 /* A non-type template parm. */
21233 /* A constant with literal type and is initialized
21234 with an expression that is value-dependent.
21236 Note that a non-dependent parenthesized initializer will have
21237 already been replaced with its constant value, so if we see
21238 a TREE_LIST it must be dependent. */
21242 /* cp_finish_decl doesn't fold reference initializers. */
21253 /* These expressions are value-dependent if the type to which
21254 the cast occurs is dependent or the expression being casted
21255 is value-dependent. */
21256 {
21262 /* A functional cast has a list of operands. */
21265 {
21266 /* If there are no operands, it must be an expression such
21267 as "int()". This should not happen for aggregate types
21268 because it would form non-constant expressions. */
21273 }
21279 }
21284 /* FALLTHRU */
21287 /* A `sizeof' expression is value-dependent if the operand is
21288 type-dependent or is a pack expansion. */
21297 /* An 'encode' expression is value-dependent if the operand is
21298 type-dependent. */
21307 /* All instantiation-dependent expressions should also be considered
21308 value-dependent. */
21316 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
21317 is value-dependent. */
21318 {
21327 }
21330 {
21334 }
21345 {
21349 }
21352 {
21359 {
21361 /* In a call to a constexpr member function, look through the
21362 implicit ADDR_EXPR on the object argument so that it doesn't
21363 cause the call to be considered value-dependent. We also
21364 look through it in potential_constant_expression. */
21371 }
21373 }
21376 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
21377 type-dependent. */
21381 {
21383 tree val;
21390 }
21393 /* Treat a GNU statement expression as dependent to avoid crashing
21394 under instantiate_non_dependent_expr; it can't be constant. */
21398 /* A constant expression is value-dependent if any subexpression is
21399 value-dependent. */
21401 {
21408 {
21412 {
21415 /* In some cases, some of the operands may be missing.l
21416 (For example, in the case of PREDECREMENT_EXPR, the
21417 amount to increment by may be missing.) That doesn't
21418 make the expression dependent. */
21421 }
21422 }
21426 }
21428 }
21430 /* The expression is not value-dependent. */
21432 }
21434 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
21435 [temp.dep.expr]. Note that an expression with no type is
21436 considered dependent. Other parts of the compiler arrange for an
21437 expression with type-dependent subexpressions to have no type, so
21438 this function doesn't have to be fully recursive. */
21440 bool
21442 {
21449 /* An unresolved name is always dependent. */
21453 /* Some expression forms are never type-dependent. */
21466 /* The types of these expressions depends only on the type to which
21467 the cast occurs. */
21476 /* The types of these expressions depends only on the type created
21477 by the expression. */
21480 {
21481 /* For NEW_EXPR tree nodes created inside a template, either
21482 the object type itself or a TREE_LIST may appear as the
21483 operand 1. */
21486 /* This is an array type. We need to check array dimensions
21487 as well. */
21489 || value_dependent_expression_p
21491 else
21493 }
21496 {
21500 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
21501 contains an identifier associated by name lookup with one or more
21502 declarations declared with a dependent type, or...a
21503 nested-name-specifier or qualified-id that names a member of an
21504 unknown specialization. */
21507 }
21512 && (any_dependent_template_arguments_p
21524 {
21525 tree elt;
21529 {
21532 }
21534 }
21536 /* A static data member of the current instantiation with incomplete
21537 array type is type-dependent, as the definition and specializations
21538 can have different bounds. */
21545 /* An array of unknown bound depending on a variadic parameter, eg:
21547 template<typename... Args>
21548 void foo (Args... args)
21549 {
21550 int arr[] = { args... };
21551 }
21553 template<int... vals>
21554 void bar ()
21555 {
21556 int arr[] = { vals... };
21557 }
21559 If the array has no length and has an initializer, it must be that
21560 we couldn't determine its length in cp_complete_array_type because
21561 it is dependent. */
21568 /* A variable template specialization is type-dependent if it has any
21569 dependent template arguments. */
21576 /* Always dependent, on the number of arguments if nothing else. */
21581 {
21586 {
21592 }
21593 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
21598 {
21603 }
21606 {
21611 }
21616 {
21620 }
21622 }
21627 }
21629 /* walk_tree callback function for instantiation_dependent_expression_p,
21630 below. Returns non-zero if a dependent subexpression is found. */
21632 static tree
21635 {
21637 {
21638 /* We don't have to worry about decltype currently because decltype
21639 of an instantiation-dependent expr is a dependent type. This
21640 might change depending on the resolution of DR 1172. */
21643 }
21646 {
21647 /* Don't treat an argument list as dependent just because it has no
21648 TREE_TYPE. */
21655 /* A constant with a dependent initializer is dependent. */
21663 /* Handle expressions with type operands. */
21668 {
21673 {
21676 else
21677 {
21680 }
21681 }
21683 }
21695 /* In a template, finish_class_member_access_expr creates a
21696 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
21697 type-dependent, so that we can check access control at
21698 instantiation time (PR 42277). See also Core issue 1273. */
21705 else
21708 /* Treat statement-expressions as dependent. */
21714 }
21718 else
21720 }
21722 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
21723 sense defined by the ABI:
21725 "An expression is instantiation-dependent if it is type-dependent
21726 or value-dependent, or it has a subexpression that is type-dependent
21727 or value-dependent." */
21729 bool
21731 {
21732 tree result;
21743 }
21745 /* Like type_dependent_expression_p, but it also works while not processing
21746 a template definition, i.e. during substitution or mangling. */
21748 bool
21750 {
21756 }
21758 /* Returns TRUE if ARGS contains a type-dependent expression. */
21760 bool
21762 {
21764 tree arg;
21767 {
21770 }
21772 }
21774 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21775 expressions) contains any type-dependent expressions. */
21777 bool
21779 {
21785 }
21787 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21788 expressions) contains any value-dependent expressions. */
21790 bool
21792 {
21798 }
21800 /* Returns TRUE if the ARG (a template argument) is dependent. */
21802 bool
21804 {
21808 /* Assume a template argument that was wrongly written by the user
21809 is dependent. This is consistent with what
21810 any_dependent_template_arguments_p [that calls this function]
21811 does. */
21822 {
21826 {
21829 }
21832 }
21835 else
21838 }
21840 /* Returns true if ARGS (a collection of template arguments) contains
21841 any types that require structural equality testing. */
21843 bool
21845 {
21855 {
21858 {
21864 {
21865 /* Look inside the argument pack. */
21868 }
21871 {
21884 }
21885 }
21886 }
21889 }
21891 /* Returns true if ARGS (a collection of template arguments) contains
21892 any dependent arguments. */
21894 bool
21896 {
21906 {
21911 }
21914 }
21916 /* Returns TRUE if the template TMPL is dependent. */
21918 bool
21920 {
21922 {
21924 {
21928 }
21930 }
21932 /* Template template parameters are dependent. */
21936 /* So are names that have not been looked up. */
21939 /* So are member templates of dependent classes. */
21943 }
21945 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
21947 bool
21949 {
21952 }
21954 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
21955 is dependent. */
21957 bool
21959 {
21966 {
21987 {
21991 }
21995 {
21999 {
22004 }
22005 }
22006 }
22009 }
22011 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
22012 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
22013 no such TYPE can be found. Note that this function peers inside
22014 uninstantiated templates and therefore should be used only in
22015 extremely limited situations. ONLY_CURRENT_P restricts this
22016 peering to the currently open classes hierarchy (which is required
22017 when comparing types). */
22019 tree
22021 {
22022 tree scope;
22023 tree name;
22024 tree decl;
22026 tree pushed_scope;
22027 tree result;
22032 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
22033 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
22034 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
22035 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
22036 identifier of the TYPENAME_TYPE anymore.
22037 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
22038 TYPENAME_TYPE instead, we avoid messing up with a possible
22039 typedef variant case. */
22042 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
22043 it first before we can figure out what NAME refers to. */
22045 {
22047 /* Given a class template A with a dependent base with nested type C,
22048 typedef typename A::C::C C will land us here, as trying to resolve
22049 the initial A::C leads to the local C typedef, which leads back to
22050 A::C::C. So we break the recursion now. */
22052 else
22054 }
22055 /* If we don't know what SCOPE refers to, then we cannot resolve the
22056 TYPENAME_TYPE. */
22059 /* If the SCOPE is a template type parameter, we have no way of
22060 resolving the name. */
22063 /* If the SCOPE is not the current instantiation, there's no reason
22064 to look inside it. */
22067 /* If this is a typedef, we don't want to look inside (c++/11987). */
22070 /* If SCOPE isn't the template itself, it will not have a valid
22071 TYPE_FIELDS list. */
22073 /* scope is either the template itself or a compatible instantiation
22074 like X<T>, so look up the name in the original template. */
22076 else
22077 /* scope is a partial instantiation, so we can't do the lookup or we
22078 will lose the template arguments. */
22080 /* Enter the SCOPE so that name lookup will be resolved as if we
22081 were in the class definition. In particular, SCOPE will no
22082 longer be considered a dependent type. */
22084 /* Look up the declaration. */
22086 tf_warning_or_error);
22090 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
22091 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
22096 {
22100 }
22103 {
22104 tree tmpl;
22105 tree args;
22106 /* Obtain the template and the arguments. */
22109 /* Instantiate the template. */
22115 }
22117 /* Leave the SCOPE. */
22121 /* If we failed to resolve it, return the original typename. */
22125 /* If lookup found a typename type, resolve that too. */
22127 {
22128 /* Ill-formed programs can cause infinite recursion here, so we
22129 must catch that. */
22133 }
22135 /* Qualify the resulting type. */
22141 }
22143 /* EXPR is an expression which is not type-dependent. Return a proxy
22144 for EXPR that can be used to compute the types of larger
22145 expressions containing EXPR. */
22147 tree
22149 {
22150 tree inner_expr;
22152 #ifdef ENABLE_CHECKING
22153 /* Try to get a constant value for all non-dependent expressions in
22154 order to expose bugs in *_dependent_expression_p and constexpr. */
22157 #endif
22159 /* Preserve OVERLOADs; the functions must be available to resolve
22160 types. */
22171 /* There is no need to return a proxy for a variable. */
22174 /* Preserve string constants; conversions from string constants to
22175 "char *" are allowed, even though normally a "const char *"
22176 cannot be used to initialize a "char *". */
22179 /* Preserve void and arithmetic constants, as an optimization -- there is no
22180 reason to create a new node. */
22185 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
22186 There is at least one place where we want to know that a
22187 particular expression is a throw-expression: when checking a ?:
22188 expression, there are special rules if the second or third
22189 argument is a throw-expression. */
22193 /* Don't wrap an initializer list, we need to be able to look inside. */
22197 /* Don't wrap a dummy object, we need to be able to test for it. */
22216 /* If the type is unknown, it can't really be non-dependent */
22219 /* Otherwise, build a NON_DEPENDENT_EXPR. */
22221 }
22223 /* ARGS is a vector of expressions as arguments to a function call.
22224 Replace the arguments with equivalent non-dependent expressions.
22225 This modifies ARGS in place. */
22227 void
22229 {
22231 tree arg;
22234 {
22238 }
22239 }
22241 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
22242 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
22243 parms. */
22245 static tree
22247 {
22260 }
22262 tree
22264 {
22266 }
22268 tree
22270 {
22272 }
22274 /* Given type ARG, return std::initializer_list<ARG>. */
22276 static tree
22278 {
22279 tree std_init_list = namespace_binding
22281 tree argvec;
22283 {
22287 }
22292 }
22294 /* Replace auto in TYPE with std::initializer_list<auto>. */
22296 static tree
22298 {
22305 }
22307 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
22308 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
22310 tree
22312 {
22313 tree targs;
22319 /* Defining a subset of type-dependent expressions that we can deduce
22320 from ahead of time isn't worth the trouble. */
22323 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
22324 with either a new invented type template parameter U or, if the
22325 initializer is a braced-init-list (8.5.4), with
22326 std::initializer_list<U>. */
22328 {
22333 else
22334 {
22338 "for deduction to %<std::initializer_list%>, use copy-"
22341 }
22342 }
22348 {
22354 {
22357 }
22358 }
22359 else
22360 {
22371 {
22373 /* Try again at instantiation time. */
22376 /* If type is error_mark_node a diagnostic must have been
22377 emitted by now. Also, having a mention to '<type error>'
22378 in the diagnostic is not really useful to the user. */
22379 {
22383 else
22385 }
22387 }
22388 }
22390 /* If the list of declarators contains more than one declarator, the type
22391 of each declared variable is determined as described above. If the
22392 type deduced for the template parameter U is not the same in each
22393 deduction, the program is ill-formed. */
22396 {
22402 else
22406 }
22412 }
22414 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
22415 result. */
22417 tree
22419 {
22420 tree argvec;
22427 /* For a late-specified return type in a template type-parameter, we
22428 need to add a dummy argument level for its parmlist. */
22429 argvec = add_to_template_args
22434 }
22436 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
22437 'decltype(auto)'. */
22439 bool
22441 {
22446 else
22448 }
22450 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
22451 a use of `auto'. Returns NULL_TREE otherwise. */
22453 tree
22455 {
22457 }
22459 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
22460 'decltype(auto)' or a concept. */
22462 bool
22464 {
22466 }
22468 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
22469 a concept identifier) iff TYPE contains a use of a generic type. Returns
22470 NULL_TREE otherwise. */
22472 tree
22474 {
22476 }
22479 /* For a given template T, return the vector of typedefs referenced
22480 in T for which access check is needed at T instantiation time.
22481 T is either a FUNCTION_DECL or a RECORD_TYPE.
22482 Those typedefs were added to T by the function
22483 append_type_to_template_for_access_check. */
22487 {
22488 tree ti;
22499 {
22504 }
22507 }
22509 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
22510 tied to T. That list of typedefs will be access checked at
22511 T instantiation time.
22512 T is either a FUNCTION_DECL or a RECORD_TYPE.
22513 TYPE_DECL is a TYPE_DECL node representing a typedef.
22514 SCOPE is the scope through which TYPE_DECL is accessed.
22515 LOCATION is the location of the usage point of TYPE_DECL.
22517 This function is a subroutine of
22518 append_type_to_template_for_access_check. */
22520 static void
22522 tree type_decl,
22523 tree scope,
22524 location_t location)
22525 {
22526 qualified_typedef_usage_t typedef_usage;
22527 tree ti;
22534 && type_decl
22548 }
22550 /* Append TYPE_DECL to the template TEMPL.
22551 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
22552 At TEMPL instanciation time, TYPE_DECL will be checked to see
22553 if it can be accessed through SCOPE.
22554 LOCATION is the location of the usage point of TYPE_DECL.
22556 e.g. consider the following code snippet:
22558 class C
22559 {
22560 typedef int myint;
22561 };
22563 template<class U> struct S
22564 {
22565 C::myint mi; // <-- usage point of the typedef C::myint
22566 };
22568 S<char> s;
22570 At S<char> instantiation time, we need to check the access of C::myint
22571 In other words, we need to check the access of the myint typedef through
22572 the C scope. For that purpose, this function will add the myint typedef
22573 and the scope C through which its being accessed to a list of typedefs
22574 tied to the template S. That list will be walked at template instantiation
22575 time and access check performed on each typedefs it contains.
22576 Note that this particular code snippet should yield an error because
22577 myint is private to C. */
22579 void
22581 tree type_decl,
22582 tree scope,
22583 location_t location)
22584 {
22590 /* Make sure we don't append the type to the template twice. */
22597 }
22599 /* Convert the generic type parameters in PARM that match the types given in the
22600 range [START_IDX, END_IDX) from the current_template_parms into generic type
22601 packs. */
22603 tree
22605 {
22616 {
22617 /* Create a distinct parameter pack type from the current parm and add it
22618 to the replacement args to tsubst below into the generic function
22619 parameter. */
22634 }
22640 /* If there are more levels then build up the replacement with the outer
22641 template parms. */
22645 replacement);
22648 }
22651 /* Set up the hash tables for template instantiations. */
22653 void
22655 {
22658 }
22660 /* Print stats about the template hash tables for -fstats. */
22662 void
22664 {
22673 }