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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2016 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
210 location_t);
218 /* Make the current scope suitable for access checking when we are
219 processing T. T can be FUNCTION_DECL for instantiated function
220 template, VAR_DECL for static member variable, or TYPE_DECL for
221 alias template (needed by instantiate_decl). */
223 static void
225 {
233 else
237 {
238 saved_access_scope = tree_cons
241 }
242 }
244 /* Restore the scope set up by push_access_scope. T is the node we
245 are processing. */
247 static void
249 {
251 {
254 }
258 else
260 }
262 /* Do any processing required when DECL (a member template
263 declaration) is finished. Returns the TEMPLATE_DECL corresponding
264 to DECL, unless it is a specialization, in which case the DECL
265 itself is returned. */
267 tree
269 {
276 {
277 tree type;
285 {
289 }
291 }
295 {
297 {
300 }
301 else
303 }
304 else
308 }
310 /* Create a template info node. */
312 tree
314 {
319 }
321 /* Return the template info node corresponding to T, whatever T is. */
323 tree
325 {
347 }
349 /* Returns the template nesting level of the indicated class TYPE.
351 For example, in:
352 template <class T>
353 struct A
354 {
355 template <class U>
356 struct B {};
357 };
359 A<T>::B<U> has depth two, while A<T> has depth one.
360 Both A<T>::B<int> and A<int>::B<U> have depth one, if
361 they are instantiations, not specializations.
363 This function is guaranteed to return 0 if passed NULL_TREE so
364 that, for example, `template_class_depth (current_class_type)' is
365 always safe. */
367 int
369 {
373 {
384 else
386 }
389 }
391 /* Subroutine of maybe_begin_member_template_processing.
392 Returns true if processing DECL needs us to push template parms. */
394 static bool
396 {
402 }
404 /* Subroutine of maybe_begin_member_template_processing.
405 Push the template parms in PARMS, starting from LEVELS steps into the
406 chain, and ending at the beginning, since template parms are listed
407 innermost first. */
409 static void
411 {
419 current_template_parms
425 NULL);
427 {
436 {
443 /* Push the CONST_DECL. */
449 }
450 }
451 }
453 /* Restore the template parameter context for a member template, a
454 friend template defined in a class definition, or a non-template
455 member of template class. */
457 void
459 {
460 tree parms;
465 {
468 /* Disregard full specializations (c++/60999). */
471 }
474 {
479 {
482 }
485 }
487 /* Remember how many levels of template parameters we pushed so that
488 we can pop them later. */
490 }
492 /* Undo the effects of maybe_begin_member_template_processing. */
494 void
496 {
505 {
509 }
510 }
512 /* Return a new template argument vector which contains all of ARGS,
513 but has as its innermost set of arguments the EXTRA_ARGS. */
515 static tree
517 {
518 tree new_args;
536 }
538 /* Like add_to_template_args, but only the outermost ARGS are added to
539 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
540 (EXTRA_ARGS) levels are added. This function is used to combine
541 the template arguments from a partial instantiation with the
542 template arguments used to attain the full instantiation from the
543 partial instantiation. */
545 static tree
547 {
548 tree new_args;
550 /* If there are more levels of EXTRA_ARGS than there are ARGS,
551 something very fishy is going on. */
554 /* If *all* the new arguments will be the EXTRA_ARGS, just return
555 them. */
559 /* For the moment, we make ARGS look like it contains fewer levels. */
564 /* Now, we restore ARGS to its full dimensions. */
568 }
570 /* Return the N levels of innermost template arguments from the ARGS. */
572 tree
574 {
575 tree new_args;
581 /* If N is 1, just return the innermost set of template arguments. */
585 /* If we're not removing anything, just return the arguments we were
586 given. */
592 /* Make a new set of arguments, not containing the outer arguments. */
599 }
601 /* The inverse of get_innermost_template_args: Return all but the innermost
602 EXTRA_LEVELS levels of template arguments from the ARGS. */
604 static tree
606 {
607 tree new_args;
613 /* If N is 1, just return the outermost set of template arguments. */
617 /* If we're not removing anything, just return the arguments we were
618 given. */
623 /* Make a new set of arguments, not containing the inner arguments. */
630 }
632 /* We've got a template header coming up; push to a new level for storing
633 the parms. */
635 void
637 {
638 /* We use a non-tag-transparent scope here, which causes pushtag to
639 put tags in this scope, rather than in the enclosing class or
640 namespace scope. This is the right thing, since we want
641 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
642 global template class, push_template_decl handles putting the
643 TEMPLATE_DECL into top-level scope. For a nested template class,
644 e.g.:
646 template <class T> struct S1 {
647 template <class T> struct S2 {};
648 };
650 pushtag contains special code to call pushdecl_with_scope on the
651 TEMPLATE_DECL for S2. */
657 /* Add a dummy parameter level while we process the parameter list. */
658 current_template_parms
661 current_template_parms);
662 }
664 /* This routine is called when a specialization is declared. If it is
665 invalid to declare a specialization here, an error is reported and
666 false is returned, otherwise this routine will return true. */
668 static bool
670 {
673 /* [temp.expl.spec]
675 An explicit specialization shall be declared in the namespace of
676 which the template is a member, or, for member templates, in the
677 namespace of which the enclosing class or enclosing class
678 template is a member. An explicit specialization of a member
679 function, member class or static data member of a class template
680 shall be declared in the namespace of which the class template
681 is a member. */
683 {
686 }
688 /* [temp.expl.spec]
690 In an explicit specialization declaration for a member of a class
691 template or a member template that appears in namespace scope,
692 the member template and some of its enclosing class templates may
693 remain unspecialized, except that the declaration shall not
694 explicitly specialize a class member template if its enclosing
695 class templates are not explicitly specialized as well. */
697 {
700 }
703 }
705 /* We've just seen template <>. */
707 bool
709 {
713 }
715 /* Called at then end of processing a declaration preceded by
716 template<>. */
718 void
720 {
723 }
725 /* Any template <>'s that we have seen thus far are not referring to a
726 function specialization. */
728 void
730 {
733 }
735 /* We've just seen a template header. If SPECIALIZATION is nonzero,
736 it was of the form template <>. */
738 static void
740 {
742 template_header_count++;
743 }
745 /* We're beginning an explicit instantiation. */
747 void
749 {
752 }
755 void
757 {
760 }
762 /* An explicit specialization or partial specialization of TMPL is being
763 declared. Check that the namespace in which the specialization is
764 occurring is permissible. Returns false iff it is invalid to
765 specialize TMPL in the current namespace. */
767 static bool
769 {
772 /* [tmpl.expl.spec]
774 An explicit specialization shall be declared in the namespace of
775 which the template is a member, or, for member templates, in the
776 namespace of which the enclosing class or enclosing class
777 template is a member. An explicit specialization of a member
778 function, member class or static data member of a class template
779 shall be declared in the namespace of which the class template is
780 a member. */
783 {
786 }
788 /* Same or super-using namespace. */
790 else
791 {
797 }
798 }
800 /* SPEC is an explicit instantiation. Check that it is valid to
801 perform this explicit instantiation in the current namespace. */
803 static void
805 {
806 tree ns;
808 /* DR 275: An explicit instantiation shall appear in an enclosing
809 namespace of its template. */
815 }
817 // Returns the type of a template specialization only if that
818 // specialization needs to be defined. Otherwise (e.g., if the type has
819 // already been defined), the function returns NULL_TREE.
820 static tree
822 {
823 // An implicit instantiation of an incomplete type implies
824 // the definition of a new class template.
825 //
826 // template<typename T>
827 // struct S;
828 //
829 // template<typename T>
830 // struct S<T*>;
831 //
832 // Here, S<T*> is an implicit instantiation of S whose type
833 // is incomplete.
837 // It can also be the case that TYPE is a completed specialization.
838 // Continuing the previous example, suppose we also declare:
839 //
840 // template<typename T>
841 // requires Integral<T>
842 // struct S<T*>;
843 //
844 // Here, S<T*> refers to the specialization S<T*> defined
845 // above. However, we need to differentiate definitions because
846 // we intend to define a new partial specialization. In this case,
847 // we rely on the fact that the constraints are different for
848 // this declaration than that above.
849 //
850 // Note that we also get here for injected class names and
851 // late-parsed template definitions. We must ensure that we
852 // do not create new type declarations for those cases.
854 {
858 // If there are no template parameters, this cannot be a new
859 // partial template specializtion?
863 // The injected-class-name is not a new partial specialization.
867 // If the constraints are not the same as those of the primary
868 // then, we can probably create a new specialization.
872 {
876 }
878 // Also, if there's a pre-existing specialization with matching
879 // constraints, then this also isn't new.
882 {
890 }
892 // Create a new type node (and corresponding type decl)
893 // for the newly declared specialization.
899 /* We only need a separate type node for storing the definition of this
900 partial specialization; uses of S<T*> are unconstrained, so all are
901 equivalent. So keep TYPE_CANONICAL the same. */
904 // Build the corresponding type decl.
910 }
913 }
915 /* The TYPE is being declared. If it is a template type, that means it
916 is a partial specialization. Do appropriate error-checking. */
918 tree
920 {
921 tree context;
926 /* A lambda that appears in specialization context is not itself a
927 specialization. */
932 {
936 }
941 {
946 else
949 }
951 {
952 /* This is for ordinary explicit specialization and partial
953 specialization of a template class such as:
955 template <> class C<int>;
957 or:
959 template <class T> class C<T*>;
961 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
964 {
971 {
976 }
977 }
983 /* Trying to define a specialization either without a template<> header
984 or in an inappropriate place. We've already given an error, so just
985 bail now so we don't actually define the specialization. */
987 }
993 {
994 /* This is for an explicit specialization of member class
995 template according to [temp.expl.spec/18]:
997 template <> template <class U> class C<int>::D;
999 The context `C<int>' must be an implicit instantiation.
1000 Otherwise this is just a member class template declared
1001 earlier like:
1003 template <> class C<int> { template <class U> class D; };
1004 template <> template <class U> class C<int>::D;
1006 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1007 while in the second case, `C<int>::D' is a primary template
1008 and `C<T>::D' may not exist. */
1012 {
1013 tree t;
1018 {
1023 }
1025 /* Check for invalid specialization after instantiation:
1027 template <> template <> class C<int>::D<int>;
1028 template <> template <class U> class C<int>::D; */
1032 {
1036 {
1037 /* We already have a full specialization of this partial
1038 instantiation, or a full specialization has been
1039 looked up but not instantiated. Reassign it to the
1040 new member specialization template. */
1041 spec_entry elt;
1053 spec_entry **slot
1058 }
1059 else
1060 /* But if we've had an implicit instantiation, that's a
1061 problem ([temp.expl.spec]/6). */
1064 }
1066 /* Mark TYPE as a specialization. And as a result, we only
1067 have one level of template argument for the innermost
1068 class template. */
1073 }
1074 }
1076 {
1077 /* Someday C++0x may allow for enum template specialization. */
1082 else
1083 {
1086 }
1087 }
1090 }
1092 /* Returns nonzero if we can optimize the retrieval of specializations
1093 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1094 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1098 {
1101 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1102 parameter. */
1104 /* The optimized lookup depends on the fact that the
1105 template arguments for the member function template apply
1106 purely to the containing class, which is not true if the
1107 containing class is an explicit or partial
1108 specialization. */
1112 /* It is possible to have a template that is not a member
1113 template and is not a member of a template class:
1115 template <typename T>
1116 struct S { friend A::f(); };
1118 Here, the friend function is a template, but the context does
1119 not have template information. The optimized lookup relies
1120 on having ARGS be the template arguments for both the class
1121 and the function template. */
1123 }
1125 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1126 gone through coerce_template_parms by now. */
1128 static void
1130 {
1133 {
1136 {
1143 /* Allow typedefs on the type of a non-type argument, since a
1145 else
1147 }
1148 }
1150 }
1152 /* Retrieve the specialization (in the sense of [temp.spec] - a
1153 specialization is either an instantiation or an explicit
1154 specialization) of TMPL for the given template ARGS. If there is
1155 no such specialization, return NULL_TREE. The ARGS are a vector of
1156 arguments, or a vector of vectors of arguments, in the case of
1157 templates with more than one level of parameters.
1159 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1160 then we search for a partial specialization matching ARGS. This
1161 parameter is ignored if TMPL is not a class template.
1163 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1164 result is a NONTYPE_ARGUMENT_PACK. */
1166 static tree
1168 {
1178 /* There should be as many levels of arguments as there are
1179 levels of parameters. */
1189 {
1190 tree class_template;
1191 tree class_specialization;
1193 tree fns;
1196 /* The template arguments actually apply to the containing
1197 class. Find the class specialization with those
1198 arguments. */
1200 class_specialization
1204 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1205 for the specialization. */
1209 /* Iterate through the methods with the indicated name, looking
1210 for the one that has an instance of TMPL. */
1213 {
1216 /* using-declarations can add base methods to the method vec,
1217 and we don't want those here. */
1220 }
1222 }
1223 else
1224 {
1226 spec_entry elt;
1235 else
1243 }
1246 }
1248 /* Like retrieve_specialization, but for local declarations. */
1250 tree
1252 {
1258 }
1260 /* Returns nonzero iff DECL is a specialization of TMPL. */
1262 int
1264 {
1265 tree t;
1268 {
1274 }
1275 else
1276 {
1285 }
1288 }
1290 /* Returns nonzero iff DECL is a specialization of friend declaration
1291 FRIEND_DECL according to [temp.friend]. */
1293 bool
1295 {
1302 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1303 of a template class, we want to check if DECL is a specialization
1304 if this. */
1308 {
1309 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1312 }
1317 /* There is nothing to do if this is not a template friend. */
1324 /* [temp.friend/6]
1325 A member of a class template may be declared to be a friend of a
1326 non-template class. In this case, the corresponding member of
1327 every specialization of the class template is a friend of the
1328 class granting friendship.
1330 For example, given a template friend declaration
1332 template <class T> friend void A<T>::f();
1334 the member function below is considered a friend
1336 template <> struct A<int> {
1337 void f();
1338 };
1340 For this type of template friend, TEMPLATE_DEPTH below will be
1341 nonzero. To determine if DECL is a friend of FRIEND, we first
1342 check if the enclosing class is a specialization of another. */
1349 {
1350 /* Next, we check the members themselves. In order to handle
1351 a few tricky cases, such as when FRIEND_DECL's are
1353 template <class T> friend void A<T>::g(T t);
1354 template <class T> template <T t> friend void A<T>::h();
1356 and DECL's are
1358 void A<int>::g(int);
1359 template <int> void A<int>::h();
1361 we need to figure out ARGS, the template arguments from
1362 the context of DECL. This is required for template substitution
1363 of `T' in the function parameter of `g' and template parameter
1364 of `h' in the above examples. Here ARGS corresponds to `int'. */
1371 {
1373 {
1376 else
1378 current_depth++;
1379 }
1381 }
1384 {
1386 tree friend_type;
1387 tree decl_type;
1388 tree friend_args_type;
1389 tree decl_args_type;
1391 /* Make sure that both DECL and FRIEND_DECL are templates or
1392 non-templates. */
1398 {
1399 /* If both are templates, check template parameter list. */
1400 tree friend_parms
1405 friend_parms))
1409 }
1410 else
1418 /* Check if return types match. */
1422 /* Check if function parameter types match, ignoring the
1423 `this' parameter. */
1432 }
1433 else
1434 {
1435 /* DECL is a TYPE_DECL */
1439 /* Make sure that both DECL and FRIEND_DECL are templates or
1440 non-templates. */
1441 is_template
1448 {
1449 tree friend_parms;
1450 /* If both are templates, check the name of the two
1451 TEMPLATE_DECL's first because is_friend didn't. */
1456 /* Now check template parameter list. */
1457 friend_parms
1460 return comp_template_parms
1462 friend_parms);
1463 }
1464 else
1467 }
1468 }
1470 }
1472 /* Register the specialization SPEC as a specialization of TMPL with
1473 the indicated ARGS. IS_FRIEND indicates whether the specialization
1474 is actually just a friend declaration. Returns SPEC, or an
1475 equivalent prior declaration, if available.
1477 We also store instantiations of field packs in the hash table, even
1478 though they are not themselves templates, to make lookup easier. */
1480 static tree
1482 hashval_t hash)
1483 {
1484 tree fn;
1486 spec_entry elt;
1494 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1495 register it; we want the corresponding TEMPLATE_DECL instead.
1496 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1497 the more obvious `uses_template_parms (spec)' to avoid problems
1498 with default function arguments. In particular, given
1499 something like this:
1501 template <class T> void f(T t1, T t = T())
1503 the default argument expression is not substituted for in an
1504 instantiation unless and until it is actually needed. */
1508 /* We don't put these specializations in the hash table, but we might
1509 want to give an error about a mismatch. */
1511 else
1512 {
1520 slot =
1524 else
1526 }
1528 /* We can sometimes try to re-register a specialization that we've
1529 already got. In particular, regenerate_decl_from_template calls
1530 duplicate_decls which will update the specialization list. But,
1531 we'll still get called again here anyhow. It's more convenient
1532 to simply allow this than to try to prevent it. */
1536 {
1538 {
1541 {
1543 fn);
1545 }
1546 else
1547 {
1548 tree clone;
1549 /* This situation should occur only if the first
1550 specialization is an implicit instantiation, the
1551 second is an explicit specialization, and the
1552 implicit instantiation has not yet been used. That
1553 situation can occur if we have implicitly
1554 instantiated a member function and then specialized
1555 it later.
1557 We can also wind up here if a friend declaration that
1558 looked like an instantiation turns out to be a
1559 specialization:
1561 template <class T> void foo(T);
1562 class S { friend void foo<>(int) };
1563 template <> void foo(int);
1565 We transform the existing DECL in place so that any
1566 pointers to it become pointers to the updated
1567 declaration.
1569 If there was a definition for the template, but not
1570 for the specialization, we want this to look as if
1571 there were no definition, and vice versa. */
1574 /* The call to duplicate_decls will have applied
1575 [temp.expl.spec]:
1577 An explicit specialization of a function template
1578 is inline only if it is explicitly declared to be,
1579 and independently of whether its function template
1580 is.
1582 to the primary function; now copy the inline bits to
1583 the various clones. */
1585 {
1592 }
1596 }
1597 }
1599 {
1601 /* Dup decl failed, but this is a new definition. Set the
1602 line number so any errors match this new
1603 definition. */
1607 }
1608 }
1612 /* A specialization must be declared in the same namespace as the
1613 template it is specializing. */
1619 {
1628 /* If TMPL is a forward declaration of a template function, keep a list
1629 of all specializations in case we need to reassign them to a friend
1630 template later in tsubst_friend_function.
1632 Also keep a list of all variable template instantiations so that
1633 process_partial_specialization can check whether a later partial
1634 specialization would have used it. */
1637 }
1640 }
1642 /* Returns true iff two spec_entry nodes are equivalent. */
1646 bool
1648 {
1655 /* tmpl could be a FIELD_DECL for a capture pack. */
1659 {
1660 /* Partial specializations of a variable template can be distinguished by
1661 constraints. */
1665 }
1669 }
1671 /* Returns a hash for a template TMPL and template arguments ARGS. */
1673 static hashval_t
1675 {
1678 }
1680 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1681 ignoring SPEC. */
1683 hashval_t
1685 {
1687 }
1689 /* Recursively calculate a hash value for a template argument ARG, for use
1690 in the hash tables of template specializations. */
1692 hashval_t
1694 {
1714 {
1722 {
1727 }
1749 {
1753 {
1756 }
1758 }
1762 {
1765 }
1776 val = iterative_hash_template_arg
1788 val);
1790 val);
1799 /* A lambda can't appear in a template arg, but don't crash on
1800 erroneous input. */
1812 /* Now hash operands as usual. */
1817 }
1820 {
1823 {
1824 // We want an alias specialization that survived strip_typedefs
1825 // to hash differently from its TYPE_CANONICAL, to avoid hash
1826 // collisions that compare as different in template_args_equal.
1827 // These could be dependent specializations that strip_typedefs
1828 // left alone, or untouched specializations because
1829 // coerce_template_parms returns the unconverted template
1830 // arguments if it sees incomplete argument packs.
1833 }
1836 val);
1839 /* Otherwise just compare the types during lookup. */
1848 {
1853 }
1854 }
1857 }
1859 /* Unregister the specialization SPEC as a specialization of TMPL.
1860 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1861 if the SPEC was listed as a specialization of TMPL.
1863 Note that SPEC has been ggc_freed, so we can't look inside it. */
1865 bool
1867 {
1869 spec_entry elt;
1877 {
1882 }
1885 }
1887 /* Like register_specialization, but for local declarations. We are
1888 registering SPEC, an instantiation of TMPL. */
1890 void
1892 {
1894 }
1896 /* TYPE is a class type. Returns true if TYPE is an explicitly
1897 specialized class. */
1899 bool
1901 {
1905 }
1907 /* Print the list of functions at FNS, going through all the overloads
1908 for each element of the list. Alternatively, FNS can not be a
1909 TREE_LIST, in which case it will be printed together with all the
1910 overloads.
1912 MORE and *STR should respectively be FALSE and NULL when the function
1913 is called from the outside. They are used internally on recursive
1914 calls. print_candidates manages the two parameters and leaves NULL
1915 in *STR when it ends. */
1917 static void
1919 {
1925 {
1929 }
1930 else
1931 {
1934 {
1935 /* Pick the prefix string. */
1937 {
1941 }
1945 }
1948 }
1951 {
1954 }
1955 }
1957 /* Print the list of candidate FNS in an error message. FNS can also
1958 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1960 void
1962 {
1966 }
1968 /* Get a (possibly) constrained template declaration for the
1969 purpose of ordering candidates. */
1970 static tree
1972 {
1978 }
1980 /* Among candidates having the same signature, return the
1981 most constrained or NULL_TREE if there is no best candidate.
1982 If the signatures of candidates vary (e.g., template
1983 specialization vs. member function), then there can be no
1984 most constrained.
1986 Note that we don't compare constraints on the functions
1987 themselves, but rather those of their templates. */
1988 static tree
1990 {
1991 // Try to find the best candidate in a first pass.
1994 {
2001 }
2003 // Verify that the champ is better than previous candidates.
2008 }
2011 }
2014 /* Returns the template (one of the functions given by TEMPLATE_ID)
2015 which can be specialized to match the indicated DECL with the
2016 explicit template args given in TEMPLATE_ID. The DECL may be
2017 NULL_TREE if none is available. In that case, the functions in
2018 TEMPLATE_ID are non-members.
2020 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2021 specialization of a member template.
2023 The TEMPLATE_COUNT is the number of references to qualifying
2024 template classes that appeared in the name of the function. See
2025 check_explicit_specialization for a more accurate description.
2027 TSK indicates what kind of template declaration (if any) is being
2028 declared. TSK_TEMPLATE indicates that the declaration given by
2029 DECL, though a FUNCTION_DECL, has template parameters, and is
2030 therefore a template function.
2032 The template args (those explicitly specified and those deduced)
2033 are output in a newly created vector *TARGS_OUT.
2035 If it is impossible to determine the result, an error message is
2036 issued. The error_mark_node is returned to indicate failure. */
2038 static tree
2040 tree decl,
2044 tmpl_spec_kind tsk)
2045 {
2046 tree fns;
2047 tree targs;
2048 tree explicit_targs;
2051 /* A TREE_LIST of templates of which DECL may be a specialization.
2052 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2053 corresponding TREE_PURPOSE is the set of template arguments that,
2054 when used to instantiate the template, would produce a function
2055 with the signature of DECL. */
2065 /* We shouldn't be specializing a member template of an
2066 unspecialized class template; we already gave an error in
2067 check_specialization_scope, now avoid crashing. */
2070 {
2073 }
2081 /* Check for baselinks. */
2086 {
2089 }
2091 {
2094 }
2096 /* Count the number of template headers specified for this
2097 specialization. */
2107 {
2110 tf_warning_or_error,
2114 }
2116 {
2120 {
2121 tree decl_arg_types;
2122 tree fn_arg_types;
2123 tree insttype;
2125 /* In case of explicit specialization, we need to check if
2126 the number of template headers appearing in the specialization
2127 is correct. This is usually done in check_explicit_specialization,
2128 but the check done there cannot be exhaustive when specializing
2129 member functions. Consider the following code:
2131 template <> void A<int>::f(int);
2132 template <> template <> void A<int>::f(int);
2134 Assuming that A<int> is not itself an explicit specialization
2135 already, the first line specializes "f" which is a non-template
2136 member function, whilst the second line specializes "f" which
2137 is a template member function. So both lines are syntactically
2138 correct, and check_explicit_specialization does not reject
2139 them.
2141 Here, we can do better, as we are matching the specialization
2142 against the declarations. We count the number of template
2143 headers, and we check if they match TEMPLATE_COUNT + 1
2144 (TEMPLATE_COUNT is the number of qualifying template classes,
2145 plus there must be another header for the member template
2146 itself).
2148 Notice that if header_count is zero, this is not a
2149 specialization but rather a template instantiation, so there
2150 is no check we can perform here. */
2154 /* Check that the number of template arguments at the
2155 innermost level for DECL is the same as for FN. */
2163 /* DECL might be a specialization of FN. */
2167 /* For a non-static member function, we need to make sure
2168 that the const qualification is the same. Since
2169 get_bindings does not try to merge the "this" parameter,
2170 we must do the comparison explicitly. */
2176 /* Skip the "this" parameter and, for constructors of
2177 classes with virtual bases, the VTT parameter. A
2178 full specialization of a constructor will have a VTT
2179 parameter, but a template never will. */
2180 decl_arg_types
2182 fn_arg_types
2185 /* Function templates cannot be specializations; there are
2186 no partial specializations of functions. Therefore, if
2187 the type of DECL does not match FN, there is no
2188 match.
2190 Note that it should never be the case that we have both
2191 candidates added here, and for regular member functions
2192 below. */
2194 {
2198 }
2200 /* See whether this function might be a specialization of this
2201 template. Suppress access control because we might be trying
2202 to make this specialization a friend, and we have already done
2203 access control for the declaration of the specialization. */
2209 /* We cannot deduce template arguments that when used to
2210 specialize TMPL will produce DECL. */
2213 /* Remove, from the set of candidates, all those functions
2214 whose constraints are not satisfied. */
2218 // Then, try to form the new function type.
2222 fn_arg_types
2227 /* Save this template, and the arguments deduced. */
2229 }
2231 /* FN is an ordinary member function, and we need a
2232 specialization of a member template. */
2233 ;
2235 /* We can get IDENTIFIER_NODEs here in certain erroneous
2236 cases. */
2237 ;
2239 /* This is just an ordinary non-member function. Nothing can
2240 be a specialization of that. */
2241 ;
2243 /* Cannot specialize functions that are created implicitly. */
2244 ;
2245 else
2246 {
2247 tree decl_arg_types;
2249 /* This is an ordinary member function. However, since
2250 we're here, we can assume its enclosing class is a
2251 template class. For example,
2253 template <typename T> struct S { void f(); };
2254 template <> void S<int>::f() {}
2256 Here, S<int>::f is a non-template, but S<int> is a
2257 template class. If FN has the same type as DECL, we
2258 might be in business. */
2261 /* Its enclosing class is an explicit specialization
2262 of a template class. This is not a candidate. */
2267 /* The return types differ. */
2270 /* Adjust the type of DECL in case FN is a static member. */
2277 decl_arg_types))
2280 // If the deduced arguments do not satisfy the constraints,
2281 // this is not a candidate.
2285 // Add the candidate.
2287 }
2288 }
2291 {
2292 /* We have:
2294 [temp.expl.spec]
2296 It is possible for a specialization with a given function
2297 signature to be instantiated from more than one function
2298 template. In such cases, explicit specification of the
2299 template arguments must be used to uniquely identify the
2300 function template specialization being specialized.
2302 Note that here, there's no suggestion that we're supposed to
2303 determine which of the candidate templates is most
2304 specialized. However, we, also have:
2306 [temp.func.order]
2308 Partial ordering of overloaded function template
2309 declarations is used in the following contexts to select
2310 the function template to which a function template
2311 specialization refers:
2313 -- when an explicit specialization refers to a function
2314 template.
2316 So, we do use the partial ordering rules, at least for now.
2317 This extension can only serve to make invalid programs valid,
2318 so it's safe. And, there is strong anecdotal evidence that
2319 the committee intended the partial ordering rules to apply;
2320 the EDG front end has that behavior, and John Spicer claims
2321 that the committee simply forgot to delete the wording in
2322 [temp.expl.spec]. */
2325 {
2328 }
2329 }
2331 // Concepts allows multiple declarations of member functions
2332 // with the same signature. Like above, we need to rely on
2333 // on the partial ordering of those candidates to determine which
2334 // is the best.
2336 {
2338 {
2341 }
2342 }
2345 {
2352 else
2355 }
2359 {
2365 }
2367 /* We have one, and exactly one, match. */
2369 {
2373 // Propagate the candidate's constraints to the declaration.
2376 /* DECL is a re-declaration or partial instantiation of a template
2377 function. */
2380 /* It was a specialization of an ordinary member function in a
2381 template class. */
2383 }
2385 /* It was a specialization of a template. */
2388 {
2393 }
2394 else
2397 }
2399 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2400 but with the default argument values filled in from those in the
2401 TMPL_TYPES. */
2403 static tree
2405 tree tmpl_types)
2406 {
2407 tree new_spec_types;
2415 /* Substitute into the rest of the list. */
2416 new_spec_types =
2420 /* Add the default argument for this parameter. */
2423 new_spec_types);
2424 }
2426 /* DECL is an explicit specialization. Replicate default arguments
2427 from the template it specializes. (That way, code like:
2429 template <class T> void f(T = 3);
2430 template <> void f(double);
2431 void g () { f (); }
2433 works, as required.) An alternative approach would be to look up
2434 the correct default arguments at the call-site, but this approach
2435 is consistent with how implicit instantiations are handled. */
2437 static void
2439 {
2440 tree tmpl;
2441 tree spec_types;
2442 tree tmpl_types;
2443 tree new_spec_types;
2444 tree old_type;
2445 tree new_type;
2446 tree t;
2451 /* See if there's anything we need to do. */
2464 {
2465 /* Remove the this pointer, but remember the object's type for
2466 CV quals. */
2472 {
2473 /* DECL may contain more parameters than TMPL due to the extra
2474 in-charge parameter in constructors and destructors. */
2477 }
2479 {
2482 }
2483 }
2485 /* Compute the merged default arguments. */
2486 new_spec_types =
2489 /* Compute the new FUNCTION_TYPE. */
2491 {
2495 new_spec_types);
2498 /* Put the in-charge parameter back. */
2501 new_spec_types);
2505 new_spec_types);
2506 }
2507 else
2509 new_spec_types);
2519 }
2521 /* Return the number of template headers we expect to see for a definition
2522 or specialization of CTYPE or one of its non-template members. */
2524 int
2526 {
2530 {
2531 /* You're supposed to have one `template <...>' for every
2532 template class, but you don't need one for a full
2533 specialization. For example:
2535 template <class T> struct S{};
2536 template <> struct S<int> { void f(); };
2537 void S<int>::f () {}
2539 is correct; there shouldn't be a `template <>' for the
2540 definition of `S<int>::f'. */
2542 /* If CTYPE does not have template information of any
2543 kind, then it is not a template, nor is it nested
2544 within a template. */
2552 }
2555 }
2557 /* Do a simple sanity check on the template headers that precede the
2558 variable declaration DECL. */
2560 void
2562 {
2567 {
2570 "variable templates only available with "
2573 // Namespace-scope variable templates should have a template header.
2575 }
2577 {
2584 "members of an explicitly specialized class are defined "
2586 }
2587 }
2589 /* Check to see if the function just declared, as indicated in
2590 DECLARATOR, and in DECL, is a specialization of a function
2591 template. We may also discover that the declaration is an explicit
2592 instantiation at this point.
2594 Returns DECL, or an equivalent declaration that should be used
2595 instead if all goes well. Issues an error message if something is
2596 amiss. Returns error_mark_node if the error is not easily
2597 recoverable.
2599 FLAGS is a bitmask consisting of the following flags:
2601 2: The function has a definition.
2602 4: The function is a friend.
2604 The TEMPLATE_COUNT is the number of references to qualifying
2605 template classes that appeared in the name of the function. For
2606 example, in
2608 template <class T> struct S { void f(); };
2609 void S<int>::f();
2611 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2612 classes are not counted in the TEMPLATE_COUNT, so that in
2614 template <class T> struct S {};
2615 template <> struct S<int> { void f(); }
2616 template <> void S<int>::f();
2618 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2619 invalid; there should be no template <>.)
2621 If the function is a specialization, it is marked as such via
2622 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2623 is set up correctly, and it is added to the list of specializations
2624 for that template. */
2626 tree
2628 tree decl,
2631 {
2640 tmpl_spec_kind tsk;
2643 {
2646 else
2648 }
2649 else
2653 {
2656 {
2659 }
2661 {
2663 /* This could be something like:
2665 template <class T> void f(T);
2666 class S { friend void f<>(int); } */
2668 else
2669 {
2670 /* This case handles bogus declarations like template <>
2671 template <class T> void f<int>(); */
2674 declarator);
2676 }
2677 }
2681 /* The error has already been reported in
2682 check_specialization_scope. */
2688 /* Fall through. */
2701 decl);
2704 else
2708 /* Fall through. */
2714 /* In cases like template<> constexpr bool v = true;
2715 We'll give an error in check_template_variable. */
2721 else
2727 {
2728 /* This case handles bogus declarations like template <>
2729 template <class T> void f<int>(); */
2733 declarator);
2735 {
2736 /* Partial specialization of variable template. */
2740 }
2744 else
2748 ok:;
2749 }
2752 /* This is a specialization of a member template, without
2753 specialization the containing class. Something like:
2755 template <class T> struct S {
2756 template <class U> void f (U);
2757 };
2758 template <> template <class U> void S<int>::f(U) {}
2760 That's a specialization -- but of the entire template. */
2766 }
2769 /* This doesn't apply to variable templates. */
2772 {
2776 {
2780 }
2781 }
2784 {
2789 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2791 {
2792 tree fns;
2797 else
2798 {
2799 /* If there is no class context, the explicit instantiation
2800 must be at namespace scope. */
2803 /* Find the namespace binding, using the declaration
2804 context. */
2808 /* If lookup fails, look for a friend declaration so we can
2809 give a better diagnostic. */
2815 {
2818 }
2819 }
2822 }
2828 {
2830 /* A specialization in class scope. This is invalid,
2831 but the error will already have been flagged by
2832 check_specialization_scope. */
2834 else
2835 {
2836 /* It's not valid to write an explicit instantiation in
2837 class scope, e.g.:
2839 class C { template void f(); }
2841 This case is caught by the parser. However, on
2842 something like:
2844 template class C { void f(); };
2846 (which is invalid) we can get here. The error will be
2847 issued later. */
2848 ;
2849 }
2852 }
2855 {
2856 // We'll match variable templates in start_decl.
2860 /* Find the list of functions in ctype that have the same
2861 name as the declared function. */
2867 {
2872 {
2873 /* From [temp.expl.spec]:
2875 If such an explicit specialization for the member
2876 of a class template names an implicitly-declared
2877 special member function (clause _special_), the
2878 program is ill-formed.
2880 Similar language is found in [temp.explicit]. */
2883 }
2886 }
2889 {
2893 }
2894 else
2895 {
2897 tree ovl;
2899 /* For a type-conversion operator, we cannot do a
2900 name-based lookup. We might be looking for `operator
2901 int' which will be a specialization of `operator T'.
2902 So, we find *all* the conversion operators, and then
2903 select from them. */
2911 {
2913 /* There are no more conversion functions. */
2916 /* Glue all these conversion functions together
2917 with those we already have. */
2920 }
2921 }
2924 {
2927 }
2928 else
2930 }
2932 /* Figure out what exactly is being specialized at this point.
2933 Note that for an explicit instantiation, even one for a
2934 member function, we cannot tell apriori whether the
2935 instantiation is for a member template, or just a member
2936 function of a template class. Even if a member template is
2937 being instantiated, the member template arguments may be
2938 elided if they can be deduced from the rest of the
2939 declaration. */
2942 member_specialization,
2943 template_count,
2944 tsk);
2947 /* We couldn't figure out what this declaration was
2948 specializing. */
2950 else
2951 {
2961 {
2963 "friend declaration %qD is not visible to "
2967 }
2972 {
2973 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2974 is done by do_decl_instantiation later. */
2980 {
2981 /* If TMPL is not the most general template (for
2982 example, if TMPL is a friend template that is
2983 injected into namespace scope), then there will
2984 be too many levels of TARGS. Remove some of them
2985 here. */
2987 tree new_targs;
2994 }
2997 }
2999 /* If we thought that the DECL was a member function, but it
3000 turns out to be specializing a static member function,
3001 make DECL a static member function as well. */
3007 /* If this is a specialization of a member template of a
3008 template class, we want to return the TEMPLATE_DECL, not
3009 the specialization of it. */
3011 {
3016 {
3017 tree parm;
3021 /* We want to use the argument list specified in the
3022 definition, not in the original declaration. */
3027 }
3030 }
3032 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3038 /* Inherit default function arguments from the template
3039 DECL is specializing. */
3043 /* This specialization has the same protection as the
3044 template it specializes. */
3048 /* 7.1.1-1 [dcl.stc]
3050 A storage-class-specifier shall not be specified in an
3051 explicit specialization...
3053 The parser rejects these, so unless action is taken here,
3054 explicit function specializations will always appear with
3055 global linkage.
3057 The action recommended by the C++ CWG in response to C++
3058 defect report 605 is to make the storage class and linkage
3059 of the explicit specialization match the templated function:
3061 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3062 */
3064 {
3068 /* A concept cannot be specialized. */
3070 {
3072 gen_tmpl);
3074 }
3076 /* This specialization has the same linkage and visibility as
3077 the function template it specializes. */
3080 {
3083 }
3086 {
3089 }
3090 }
3092 /* If DECL is a friend declaration, declared using an
3093 unqualified name, the namespace associated with DECL may
3094 have been set incorrectly. For example, in:
3096 template <typename T> void f(T);
3097 namespace N {
3098 struct S { friend void f<int>(int); }
3099 }
3101 we will have set the DECL_CONTEXT for the friend
3102 declaration to N, rather than to the global namespace. */
3107 /* This is not really a declaration of a specialization.
3108 It's just the name of an instantiation. But, it's not
3109 a request for an instantiation, either. */
3112 /* A specialization is not necessarily COMDAT. */
3118 /* If this is a full specialization, register it so that we can find
3119 it again. Partial specializations will be registered in
3120 process_partial_specialization. */
3125 /* A 'structor should already have clones. */
3131 }
3132 }
3135 }
3137 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3138 parameters. These are represented in the same format used for
3139 DECL_TEMPLATE_PARMS. */
3141 int
3143 {
3144 const_tree p1;
3145 const_tree p2;
3153 {
3165 {
3169 /* If either of the template parameters are invalid, assume
3170 they match for the sake of error recovery. */
3183 }
3184 }
3187 /* One set of parameters has more parameters lists than the
3188 other. */
3192 }
3194 /* Determine whether PARM is a parameter pack. */
3196 bool
3198 {
3199 /* Determine if we have a non-type template parameter pack. */
3206 /* If this is a list of template parameters, we could get a
3207 TYPE_DECL or a TEMPLATE_DECL. */
3211 /* Otherwise it must be a type template parameter. */
3215 }
3217 /* Determine if T is a function parameter pack. */
3219 bool
3221 {
3225 }
3227 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3228 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3230 tree
3232 {
3239 }
3241 /* Return true iff the function parameter PARAM_DECL was expanded
3242 from the function parameter pack PACK. */
3244 bool
3246 {
3251 /* The parameter pack and its pack arguments have the same
3252 DECL_PARM_INDEX. */
3254 }
3256 /* Determine whether ARGS describes a variadic template args list,
3257 i.e., one that is terminated by a template argument pack. */
3259 static bool
3261 {
3263 tree last_parm;
3277 }
3279 /* Generate a new name for the parameter pack name NAME (an
3280 IDENTIFIER_NODE) that incorporates its */
3282 static tree
3284 {
3285 /* Munge the name to include the parameter index. */
3286 #define NUMBUF_LEN 128
3300 }
3302 /* Return true if T is a primary function, class or alias template
3303 instantiation. */
3305 bool
3307 {
3321 }
3323 /* Return true if PARM is a template template parameter. */
3325 bool
3327 {
3329 }
3331 /* Return true iff PARM is a DECL representing a type template
3332 parameter. */
3334 bool
3336 {
3341 }
3343 /* Return the template parameters of T if T is a
3344 primary template instantiation, NULL otherwise. */
3346 tree
3348 {
3353 parms = INNERMOST_TEMPLATE_PARMS
3357 }
3359 /* Return the template parameters of the LEVELth level from the full list
3360 of template parameters PARMS. */
3362 tree
3364 {
3365 tree p;
3376 }
3378 /* Returns the template arguments of T if T is a template instantiation,
3379 NULL otherwise. */
3381 tree
3383 {
3391 }
3393 /* Return the argument pack elements of T if T is a template argument pack,
3394 NULL otherwise. */
3396 tree
3398 {
3404 }
3406 /* Structure used to track the progress of find_parameter_packs_r. */
3407 struct find_parameter_pack_data
3408 {
3409 /* TREE_LIST that will contain all of the parameter packs found by
3410 the traversal. */
3413 /* Set of AST nodes that have been visited by the traversal. */
3416 /* True iff we're making a type pack expansion. */
3418 };
3420 /* Identifies all of the argument packs that occur in a template
3421 argument and appends them to the TREE_LIST inside DATA, which is a
3422 find_parameter_pack_data structure. This is a subroutine of
3423 make_pack_expansion and uses_parameter_packs. */
3424 static tree
3426 {
3432 /* Handle type aliases/typedefs. */
3434 {
3441 }
3443 /* Identify whether this is a parameter pack or not. */
3445 {
3453 /* FALLTHRU */
3455 /* If the placeholder appears in the decl-specifier-seq of a function
3456 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3457 is a pack expansion, the invented template parameter is a template
3458 parameter pack. */
3468 {
3469 /* We don't want to walk into the type of a PARM_DECL,
3470 because we don't want to see the type parameter pack. */
3473 }
3476 /* Look through a lambda capture proxy to the field pack. */
3479 {
3485 }
3487 {
3489 find_parameter_packs_r,
3492 }
3499 /* Not a parameter pack. */
3501 }
3504 {
3505 /* Add this parameter pack to the list. */
3507 }
3513 /* This switch statement will return immediately if we don't find a
3514 parameter pack. */
3516 {
3521 /* Check the template itself. */
3524 /* Check the template arguments. */
3540 /* Fall through. */
3581 {
3582 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3583 type_pack_expansion_p to false so that any placeholders
3584 within the expression don't get marked as parameter packs. */
3592 }
3596 }
3599 }
3601 /* Determines if the expression or type T uses any parameter packs. */
3602 bool
3604 {
3613 }
3615 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3616 representation a base-class initializer into a parameter pack
3617 expansion. If all goes well, the resulting node will be an
3618 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3619 respectively. */
3620 tree
3622 {
3623 tree result;
3632 {
3633 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3634 class initializer. In this case, the TREE_PURPOSE will be a
3635 _TYPE node (representing the base class expansion we're
3636 initializing) and the TREE_VALUE will be a TREE_LIST
3637 containing the initialization arguments.
3639 The resulting expansion looks somewhat different from most
3640 expansions. Rather than returning just one _EXPANSION, we
3641 return a TREE_LIST whose TREE_PURPOSE is a
3642 TYPE_PACK_EXPANSION containing the bases that will be
3643 initialized. The TREE_VALUE will be identical to the
3644 original TREE_VALUE, which is a list of arguments that will
3645 be passed to each base. We do not introduce any new pack
3646 expansion nodes into the TREE_VALUE (although it is possible
3647 that some already exist), because the TREE_PURPOSE and
3648 TREE_VALUE all need to be expanded together with the same
3649 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3650 resulting TREE_PURPOSE will mention the parameter packs in
3651 both the bases and the arguments to the bases. */
3652 tree purpose;
3653 tree value;
3656 /* Determine which parameter packs will be used by the base
3657 class expansion. */
3666 {
3670 }
3673 {
3674 /* Collect the sets of parameter packs used in each of the
3675 initialization arguments. */
3677 {
3678 /* Determine which parameter packs will be expanded in this
3679 argument. */
3682 }
3683 }
3687 /* Create the pack expansion type for the base type. */
3692 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3693 they will rarely be compared to anything. */
3697 }
3702 /* Build the PACK_EXPANSION_* node. */
3703 result = for_types
3708 {
3709 /* Propagate type and const-expression information. */
3712 /* Mark this read now, since the expansion might be length 0. */
3714 }
3715 else
3716 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3717 they will rarely be compared to anything. */
3720 /* Determine which parameter packs will be expanded. */
3727 /* Make sure we found some parameter packs. */
3729 {
3732 else
3735 }
3741 }
3743 /* Checks T for any "bare" parameter packs, which have not yet been
3744 expanded, and issues an error if any are found. This operation can
3745 only be done on full expressions or types (e.g., an expression
3746 statement, "if" condition, etc.), because we could have expressions like:
3748 foo(f(g(h(args)))...)
3750 where "args" is a parameter pack. check_for_bare_parameter_packs
3751 should not be called for the subexpressions args, h(args),
3752 g(h(args)), or f(g(h(args))), because we would produce erroneous
3753 error messages.
3755 Returns TRUE and emits an error if there were bare parameter packs,
3756 returns FALSE otherwise. */
3757 bool
3759 {
3776 {
3780 {
3789 else
3794 else
3798 }
3801 }
3804 }
3806 /* Expand any parameter packs that occur in the template arguments in
3807 ARGS. */
3808 tree
3810 {
3816 /* First, determine if we need to expand anything, and the number of
3817 slots we'll need. */
3819 {
3824 {
3828 else
3830 }
3831 else
3832 {
3834 num_result_args++;
3835 }
3836 }
3838 /* If no expansion is necessary, we're done. */
3842 /* Expand arguments. */
3845 non_default_args_count =
3848 {
3851 {
3858 }
3859 else
3860 {
3863 }
3864 }
3868 }
3870 /* Checks if DECL shadows a template parameter.
3872 [temp.local]: A template-parameter shall not be redeclared within its
3873 scope (including nested scopes).
3875 Emits an error and returns TRUE if the DECL shadows a parameter,
3876 returns FALSE otherwise. */
3878 bool
3880 {
3881 tree olddecl;
3883 /* If we're not in a template, we can't possibly shadow a template
3884 parameter. */
3888 /* Figure out what we're shadowing. */
3893 /* If there's no previous binding for this name, we're not shadowing
3894 anything, let alone a template parameter. */
3898 /* If we're not shadowing a template parameter, we're done. Note
3899 that OLDDECL might be an OVERLOAD (or perhaps even an
3900 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3901 node. */
3905 /* We check for decl != olddecl to avoid bogus errors for using a
3906 name inside a class. We check TPFI to avoid duplicate errors for
3907 inline member templates. */
3913 /* Don't complain about the injected class name, as we've already
3914 complained about the class itself. */
3921 else
3926 }
3928 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3929 ORIG_LEVEL, DECL, and TYPE. */
3931 static tree
3935 tree decl,
3936 tree type)
3937 {
3948 }
3950 /* Find the canonical type parameter for the given template type
3951 parameter. Returns the canonical type parameter, which may be TYPE
3952 if no such parameter existed. */
3954 static tree
3956 {
3957 tree list;
3971 else
3972 {
3977 }
3978 }
3980 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3981 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3982 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3983 new one is created. */
3985 static tree
3987 tsubst_flags_t complain)
3988 {
3993 {
4012 /* Template template parameters need this. */
4014 {
4021 }
4022 }
4025 }
4027 /* Process information from new template parameter PARM and append it
4028 to the LIST being built. This new parameter is a non-type
4029 parameter iff IS_NON_TYPE is true. This new parameter is a
4030 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4031 is in PARM_LOC. */
4033 tree
4036 {
4045 {
4049 {
4053 else
4055 }
4058 }
4061 {
4067 {
4068 /* [temp.param]
4070 The top-level cv-qualifiers on the template-parameter are
4071 ignored when determining its type. */
4076 && !is_parameter_pack
4077 /* If we're in a nested template parameter list, the template
4078 template parameter could be a parameter pack. */
4080 {
4081 /* This template parameter is not a parameter pack, but it
4082 should be. Complain about "bare" parameter packs. */
4085 /* Recover by calling this a parameter pack. */
4087 }
4088 }
4090 /* A template parameter is not modifiable. */
4099 processing_template_decl,
4104 }
4105 else
4106 {
4107 tree t;
4111 {
4113 /* This is for distinguishing between real templates and template
4114 template parameters */
4118 }
4119 else
4120 {
4122 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4125 }
4132 processing_template_decl,
4136 }
4140 /* Build requirements for the type/template parameter.
4141 This must be done after SET_DECL_TEMPLATE_PARM_P or
4142 process_template_parm could fail. */
4147 /* Build the parameter node linking the parameter declaration,
4148 its default argument (if any), and its constraints (if any). */
4153 }
4155 /* The end of a template parameter list has been reached. Process the
4156 tree list into a parameter vector, converting each parameter into a more
4157 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4158 as PARM_DECLs. */
4160 tree
4162 {
4167 /* Pop the dummy parameter level and add the real one. */
4170 current_template_parms
4175 {
4179 }
4184 }
4186 // Explicitly indicate the end of the template parameter list. We assume
4187 // that the current template parameters have been constructed and/or
4188 // managed explicitly, as when creating new template template parameters
4189 // from a shorthand constraint.
4190 void
4192 {
4194 }
4196 /* end_template_decl is called after a template declaration is seen. */
4198 void
4200 {
4206 /* This matches the pushlevel in begin_template_parm_list. */
4211 }
4213 /* Takes a TREE_LIST representing a template parameter and convert it
4214 into an argument suitable to be passed to the type substitution
4215 functions. Note that If the TREE_LIST contains an error_mark
4216 node, the returned argument is error_mark_node. */
4218 tree
4220 {
4233 {
4237 {
4238 /* Turn this argument into a TYPE_ARGUMENT_PACK
4239 with a single element, which expands T. */
4248 }
4249 }
4250 else
4251 {
4255 {
4256 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4257 with a single element, which expands T. */
4269 }
4270 else
4272 }
4274 }
4276 /* Given a set of template parameters, return them as a set of template
4277 arguments. The template parameters are represented as a TREE_VEC, in
4278 the form documented in cp-tree.h for template arguments. */
4280 static tree
4282 {
4283 tree header;
4288 /* If there is only one level of template parameters, we do not
4289 create a TREE_VEC of TREE_VECs. Instead, we return a single
4290 TREE_VEC containing the arguments. */
4295 {
4308 else
4310 }
4313 }
4315 /* Within the declaration of a template, return the currently active
4316 template parameters as an argument TREE_VEC. */
4318 static tree
4320 {
4322 }
4324 /* Update the declared TYPE by doing any lookups which were thought to be
4325 dependent, but are not now that we know the SCOPE of the declarator. */
4327 tree
4329 {
4340 /* Don't bother building up the args in this case. */
4342 {
4343 /* tsubst in the args corresponding to the template parameters,
4344 including auto if present. Most things will be unchanged, but
4345 make_typename_type and tsubst_qualified_id will resolve
4346 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4349 tree pushed;
4351 {
4355 }
4360 }
4366 {
4369 else
4371 }
4373 }
4375 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4376 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4377 the new template is a member template. */
4379 tree
4381 {
4389 }
4391 struct template_parm_data
4392 {
4393 /* The level of the template parameters we are currently
4394 processing. */
4397 /* The index of the specialization argument we are currently
4398 processing. */
4401 /* An array whose size is the number of template parameters. The
4402 elements are nonzero if the parameter has been used in any one
4403 of the arguments processed so far. */
4406 /* An array whose size is the number of template arguments. The
4407 elements are nonzero if the argument makes use of template
4408 parameters of this level. */
4410 };
4412 /* Subroutine of push_template_decl used to see if each template
4413 parameter in a partial specialization is used in the explicit
4414 argument list. If T is of the LEVEL given in DATA (which is
4415 treated as a template_parm_data*), then DATA->PARMS is marked
4416 appropriately. */
4418 static int
4420 {
4428 {
4431 }
4433 /* Return zero so that for_each_template_parm will continue the
4434 traversal of the tree; we want to mark *every* template parm. */
4436 }
4438 /* Process the partial specialization DECL. */
4440 static tree
4442 {
4449 tree inner_parms;
4450 tree inst;
4460 /* A concept cannot be specialized. */
4462 {
4465 }
4470 /* We check that each of the template parameters given in the
4471 partial specialization is used in the argument list to the
4472 specialization. For example:
4474 template <class T> struct S;
4475 template <class T> struct S<T*>;
4477 The second declaration is OK because `T*' uses the template
4478 parameter T, whereas
4480 template <class T> struct S<int>;
4482 is no good. Even trickier is:
4484 template <class T>
4485 struct S1
4486 {
4487 template <class U>
4488 struct S2;
4489 template <class U>
4490 struct S2<T>;
4491 };
4493 The S2<T> declaration is actually invalid; it is a
4494 full-specialization. Of course,
4496 template <class U>
4497 struct S2<T (*)(U)>;
4499 or some such would have been OK. */
4507 {
4512 NULL,
4514 }
4517 {
4518 /* One of the template parms was not used in a deduced context in the
4519 specialization. */
4521 {
4525 }
4529 }
4534 /* [temp.class.spec]
4536 The argument list of the specialization shall not be identical to
4537 the implicit argument list of the primary template. */
4538 tree main_args
4541 && (!flag_concepts
4544 {
4548 else
4552 }
4554 /* A partial specialization that replaces multiple parameters of the
4555 primary template with a pack expansion is less specialized for those
4556 parameters. */
4558 {
4560 "primary template because it replaces multiple parameters "
4564 }
4566 /* [temp.class.spec]
4568 A partially specialized non-type argument expression shall not
4569 involve template parameters of the partial specialization except
4570 when the argument expression is a simple identifier.
4572 The type of a template parameter corresponding to a specialized
4573 non-type argument shall not be dependent on a parameter of the
4574 specialization.
4576 Also, we verify that pack expansions only occur at the
4577 end of the argument list. */
4581 {
4588 {
4589 /* Extract the arguments from the argument pack. We'll be
4590 iterating over these in the following loop. */
4593 }
4596 {
4598 /* Get the Jth argument in the parameter pack. */
4602 {
4603 /* Pack expansions must come at the end of the
4604 argument list. */
4607 {
4611 else
4614 }
4615 }
4618 /* We only care about the pattern. */
4624 /* This next two lines are the `argument expression is not just a
4625 simple identifier' condition and also the `specialized
4626 non-type argument' bit. */
4630 {
4634 arg);
4635 else
4636 {
4637 /* Look at the corresponding template parameter,
4638 marking which template parameters its type depends
4639 upon. */
4643 {
4644 /* We haven't yet initialized TPD2. Do so now. */
4646 /* The number of parameters here is the number in the
4647 main template, which, as checked in the assertion
4648 above, is NARGS. */
4652 }
4654 /* Mark the template parameters. But this time, we're
4655 looking for the template parameters of the main
4656 template, not in the specialization. */
4663 NULL,
4667 {
4668 /* The type depended on some template parameters.
4669 If they are fully specialized in the
4670 specialization, that's OK. */
4679 "type %qT of template argument %qE depends "
4681 "type %qT of template argument %qE depends "
4683 type,
4684 arg);
4685 }
4686 }
4687 }
4688 }
4689 }
4691 /* We should only get here once. */
4695 // Build the template decl.
4705 /* We didn't register this in check_explicit_specialization so we could
4706 wait until the constraints were set. */
4708 else
4718 {
4724 {
4732 "declaration of %qD ambiguates earlier template "
4736 "partial specialization of %qD after instantiation "
4738 }
4739 }
4742 }
4744 /* PARM is a template parameter of some form; return the corresponding
4745 TEMPLATE_PARM_INDEX. */
4747 static tree
4749 {
4762 }
4764 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4765 parameter packs used by the template parameter PARM. */
4767 static void
4769 {
4770 /* A type parm can't refer to another parm. */
4774 {
4778 }
4785 }
4787 /* PARM is a template parameter pack. Return any parameter packs used in
4788 its type or the type of any of its template parameters. If there are
4789 any such packs, it will be instantiated into a fixed template parameter
4790 list by partial instantiation rather than be fully deduced. */
4792 tree
4794 {
4795 /* This can only be true in a member template. */
4798 /* This can only be true for a parameter pack. */
4801 /* A type parm can't refer to another parm. */
4815 }
4817 /* Check that a template declaration's use of default arguments and
4818 parameter packs is not invalid. Here, PARMS are the template
4819 parameters. IS_PRIMARY is true if DECL is the thing declared by
4820 a primary template. IS_PARTIAL is true if DECL is a partial
4821 specialization.
4823 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4824 declaration (but not a definition); 1 indicates a declaration, 2
4825 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4826 emitted for extraneous default arguments.
4828 Returns TRUE if there were no errors found, FALSE otherwise. */
4830 bool
4833 {
4836 tree parm_level;
4839 /* [temp.param]
4841 A default template-argument shall not be specified in a
4842 function template declaration or a function template definition, nor
4843 in the template-parameter-list of the definition of a member of a
4844 class template. */
4848 /* You can't have a function template declaration in a local
4849 scope, nor you can you define a member of a class template in a
4850 local scope. */
4858 /* A lambda doesn't have an explicit declaration; don't complain
4859 about the parms of the enclosing class. */
4866 /* If this is either a friend defined in the scope of the class
4867 or a member function. */
4873 /* And, if it was a member function, it really was defined in
4874 the scope of the class. */
4877 /* We already checked these parameters when the template was
4878 declared, so there's no need to do it again now. This function
4879 was defined in class scope, but we're processing its body now
4880 that the class is complete. */
4883 /* Core issue 226 (C++0x only): the following only applies to class
4884 templates. */
4887 {
4888 /* [temp.param]
4890 If a template-parameter has a default template-argument, all
4891 subsequent template-parameters shall have a default
4892 template-argument supplied. */
4894 {
4901 {
4911 {
4913 /* For better subsequent error-recovery, we indicate that
4914 there should have been a default argument. */
4917 }
4919 && !is_friend_decl
4920 /* Don't complain about an enclosing partial
4921 specialization. */
4926 /* A fixed parameter pack will be partially
4927 instantiated into a fixed length list. */
4929 {
4930 /* A primary class template can only have one
4931 parameter pack, at the end of the template
4932 parameter list. */
4940 }
4941 }
4942 }
4943 }
4946 || is_partial
4947 || !is_primary
4949 /* For an ordinary class template, default template arguments are
4950 allowed at the innermost level, e.g.:
4951 template <class T = int>
4952 struct S {};
4953 but, in a partial specialization, they're not allowed even
4954 there, as we have in [temp.class.spec]:
4956 The template parameter list of a specialization shall not
4957 contain default template argument values.
4959 So, for a partial specialization, or for a function template
4960 (in C++98/C++03), we look at all of them. */
4961 ;
4962 else
4963 /* But, for a primary class template that is not a partial
4964 specialization we look at all template parameters except the
4965 innermost ones. */
4968 /* Figure out what error message to issue. */
4983 else
4984 /* Per [temp.param]/9, "A default template-argument shall not be
4985 specified in the template-parameter-lists of the definition of
4986 a member of a class template that appears outside of the member's
4987 class.", thus if we aren't handling a member of a class template
4988 there is no need to examine the parameters. */
4992 /* If we're inside a class definition, there's no need to
4993 examine the parameters to the class itself. On the one
4994 hand, they will be checked when the class is defined, and,
4995 on the other, default arguments are valid in things like:
4996 template <class T = double>
4997 struct S { template <class U> void f(U); };
4998 Here the default argument for `S' has no bearing on the
4999 declaration of `f'. */
5001 else
5002 /* Check everything. */
5008 {
5015 {
5020 {
5022 {
5029 }
5031 /* Clear out the default argument so that we are not
5032 confused later. */
5034 }
5035 }
5037 /* At this point, if we're still interested in issuing messages,
5038 they must apply to classes surrounding the object declared. */
5042 }
5045 }
5047 /* Worker for push_template_decl_real, called via
5048 for_each_template_parm. DATA is really an int, indicating the
5049 level of the parameters we are interested in. If T is a template
5050 parameter of that level, return nonzero. */
5052 static int
5054 {
5060 else
5063 }
5065 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5066 DATA is really an int, indicating the innermost outer level of parameters.
5067 If T is a template parameter of that level or further out, return
5068 nonzero. */
5070 static int
5072 {
5078 else
5081 }
5083 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5084 parameters given by current_template_args, or reuses a
5085 previously existing one, if appropriate. Returns the DECL, or an
5086 equivalent one, if it is replaced via a call to duplicate_decls.
5088 If IS_FRIEND is true, DECL is a friend declaration. */
5090 tree
5092 {
5093 tree tmpl;
5094 tree args;
5095 tree info;
5096 tree ctx;
5100 /* True if the template is a member template, in the sense of
5101 [temp.mem]. */
5107 /* See if this is a partial specialization. */
5120 /* For a friend, we want the context of the friend function, not
5121 the type of which it is a friend. */
5125 /* In the case of a virtual function, we want the class in which
5126 it is defined. */
5128 else
5129 /* Otherwise, if we're currently defining some class, the DECL
5130 is assumed to be a member of the class. */
5139 /* See if this is a primary template. */
5142 /* A friend template that specifies a class context, i.e.
5143 template <typename T> friend void A<T>::f();
5144 is not primary. */
5149 else
5153 {
5160 {
5163 }
5165 {
5167 {
5170 }
5172 {
5173 /* [temp.mem]
5175 A destructor shall not be a member template. */
5178 }
5185 {
5186 /* [basic.stc.dynamic.allocation]
5188 An allocation function can be a function
5189 template. ... Template allocation functions shall
5190 have two or more parameters. */
5193 }
5194 }
5200 /* alias-declaration */
5204 else
5205 {
5208 }
5209 }
5211 /* Check to see that the rules regarding the use of default
5212 arguments are not being violated. */
5216 /* Ensure that there are no parameter packs in the type of this
5217 declaration that have not been expanded. */
5219 {
5220 /* Check each of the arguments individually to see if there are
5221 any bare parameter packs. */
5227 {
5230 {
5231 /* This is a PARM_DECL that contains unexpanded parameter
5232 packs. We have already complained about this in the
5233 check_for_bare_parameter_packs call, so just replace
5234 these types with ERROR_MARK_NODE. */
5237 }
5241 }
5243 /* Check for bare parameter packs in the return type and the
5244 exception specifiers. */
5246 /* Errors were already issued, set return type to int
5247 as the frontend doesn't expect error_mark_node as
5248 the return type. */
5252 }
5257 {
5260 }
5273 {
5278 /* If DECL is a TYPE_DECL for a class-template, then there won't
5279 be DECL_LANG_SPECIFIC. The information equivalent to
5280 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5284 {
5285 /* Since a template declaration already existed for this
5286 class-type, we must be redeclaring it here. Make sure
5287 that the redeclaration is valid. */
5289 current_template_parms,
5291 /* We don't need to create a new TEMPLATE_DECL; just use the
5292 one we already had. */
5294 }
5295 else
5296 {
5298 member_template_p);
5303 {
5304 /* A specialization of a member template of a template
5305 class. */
5309 }
5310 }
5311 }
5312 else
5313 {
5319 {
5322 }
5330 {
5331 tree new_tmpl;
5333 /* The declaration is a specialization of a member
5334 template, declared outside the class. Therefore, the
5335 innermost template arguments will be NULL, so we
5336 replace them with the arguments determined by the
5337 earlier call to check_explicit_specialization. */
5340 new_tmpl
5342 member_template_p);
5352 args,
5355 }
5357 /* Make sure the template headers we got make sense. */
5362 {
5367 }
5368 else
5370 {
5375 {
5379 else
5383 /* Avoid crash in import_export_decl. */
5386 }
5391 /* Can happen in erroneous input. */
5393 else
5395 }
5397 /* Check that the parms are used in the appropriate qualifying scopes
5398 in the declarator. */
5402 {
5408 /* Avoid crash in import_export_decl. */
5411 }
5412 }
5417 /* Push template declarations for global functions and types. Note
5418 that we do not try to push a global template friend declared in a
5419 template class; such a thing may well depend on the template
5420 parameters of the class. */
5423 {
5428 /* Hide template friend classes that haven't been declared yet. */
5430 {
5433 }
5434 }
5437 {
5443 {
5446 /* It is a conversion operator. See if the type converted to
5447 depends on innermost template operands. */
5450 depth))
5452 }
5454 /* Give template template parms a DECL_CONTEXT of the template
5455 for which they are a parameter. */
5458 {
5462 }
5468 }
5470 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5471 back to its most general template. If TMPL is a specialization,
5472 ARGS may only have the innermost set of arguments. Add the missing
5473 argument levels if necessary. */
5481 else
5482 {
5487 }
5490 && !is_friend
5493 /* Set DECL_COMDAT on template instantiations; if we force
5494 them to be emitted by explicit instantiation or -frepo,
5495 mark_needed will tell cgraph to do the right thing. */
5499 }
5501 tree
5503 {
5505 }
5507 /* FN is an inheriting constructor that inherits from the constructor
5508 template INHERITED; turn FN into a constructor template with a matching
5509 template header. */
5511 tree
5513 {
5514 tree inner_parms
5517 tree parms
5528 }
5530 /* Called when a class template TYPE is redeclared with the indicated
5531 template PARMS, e.g.:
5533 template <class T> struct S;
5534 template <class T> struct S {}; */
5536 bool
5538 {
5539 tree tmpl;
5540 tree tmpl_parms;
5544 {
5547 }
5551 /* The type is nested in some template class. Nothing to worry
5552 about here; there are no new template parameters for the nested
5553 type. */
5557 {
5559 tmpl);
5561 }
5567 {
5577 }
5580 {
5581 tree tmpl_parm;
5582 tree parm;
5583 tree tmpl_default;
5584 tree parm_default;
5598 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5599 TEMPLATE_DECL. */
5609 {
5613 }
5616 {
5617 /* We have in [temp.param]:
5619 A template-parameter may not be given default arguments
5620 by two different declarations in the same scope. */
5625 }
5628 /* Update the previous template parameters (which are the ones
5629 that will really count) with the new default value. */
5632 /* Update the new parameters, too; they'll be used as the
5633 parameters for any members. */
5636 /* Give each template template parm in this redeclaration a
5637 DECL_CONTEXT of the template for which they are a parameter. */
5639 {
5642 }
5643 }
5645 // Cannot redeclare a class template with a different set of constraints.
5647 {
5652 }
5655 }
5657 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5658 to be used when the caller has already checked
5659 (processing_template_decl
5660 && !instantiation_dependent_expression_p (expr)
5661 && potential_constant_expression (expr))
5662 and cleared processing_template_decl. */
5664 tree
5666 {
5669 complain,
5673 }
5675 /* Simplify EXPR if it is a non-dependent expression. Returns the
5676 (possibly simplified) expression. */
5678 tree
5680 {
5684 /* If we're in a template, but EXPR isn't value dependent, simplify
5685 it. We're supposed to treat:
5687 template <typename T> void f(T[1 + 1]);
5688 template <typename T> void f(T[2]);
5690 as two declarations of the same function, for example. */
5693 {
5694 processing_template_decl_sentinel s;
5696 }
5698 }
5700 tree
5702 {
5704 }
5706 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5707 an uninstantiated expression. */
5709 tree
5711 {
5715 {
5718 else
5719 {
5720 processing_template_decl_sentinel s;
5722 }
5723 }
5725 }
5727 /* True iff T is a specialization of a variable template. */
5729 bool
5731 {
5736 }
5738 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5739 template declaration, or a TYPE_DECL for an alias declaration. */
5741 bool
5743 {
5751 }
5753 /* Return TRUE iff T is a specialization of an alias template. */
5755 bool
5757 {
5758 /* It's an alias template specialization if it's an alias and its
5759 TYPE_NAME is a specialization of a primary template. */
5761 {
5765 {
5768 }
5769 }
5771 }
5773 /* An alias template is complex from a SFINAE perspective if a template-id
5774 using that alias can be ill-formed when the expansion is not, as with
5775 the void_t template. We determine this by checking whether the
5776 expansion for the alias template uses all its template parameters. */
5778 struct uses_all_template_parms_data
5779 {
5782 };
5784 static int
5786 {
5794 }
5796 static bool
5798 {
5813 }
5815 /* Return TRUE iff T is a specialization of a complex alias template with
5816 dependent template-arguments. */
5818 bool
5820 {
5823 && (any_dependent_template_arguments_p
5825 }
5827 /* Return the number of innermost template parameters in TMPL. */
5829 static int
5831 {
5834 }
5836 /* Return either TMPL or another template that it is equivalent to under DR
5837 1286: An alias that just changes the name of a template is equivalent to
5838 the other template. */
5840 static tree
5842 {
5845 {
5848 {
5853 {
5854 tree alias_args = INNERMOST_TEMPLATE_ARGS
5858 /* The alias type is equivalent to the pattern of the
5859 underlying template, so strip the alias. */
5862 }
5863 }
5865 }
5867 }
5869 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5870 must be a function or a pointer-to-function type, as specified
5871 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5872 and check that the resulting function has external linkage. */
5874 static tree
5876 tsubst_flags_t complain)
5877 {
5880 linkage_kind linkage;
5892 /* [temp.arg.nontype]/1
5894 A template-argument for a non-type, non-template template-parameter
5895 shall be one of:
5896 [...]
5897 -- the address of an object or function with external [C++11: or
5898 internal] linkage. */
5901 {
5903 {
5909 else
5912 }
5914 }
5918 {
5920 {
5925 else
5929 }
5931 }
5934 }
5936 /* Subroutine of convert_nontype_argument.
5937 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5938 Emit an error otherwise. */
5940 static bool
5942 tsubst_flags_t complain)
5943 {
5954 {
5958 }
5960 }
5962 /* Returns TRUE iff the address of OP is value-dependent.
5964 14.6.2.4 [temp.dep.temp]:
5965 A non-integral non-type template-argument is dependent if its type is
5966 dependent or it has either of the following forms
5967 qualified-id
5968 & qualified-id
5969 and contains a nested-name-specifier which specifies a class-name that
5970 names a dependent type.
5972 We generalize this to just say that the address of a member of a
5973 dependent class is value-dependent; the above doesn't cover the
5974 address of a static data member named with an unqualified-id. */
5976 static bool
5978 {
5979 /* We could use get_inner_reference here, but there's no need;
5980 this is only relevant for template non-type arguments, which
5981 can only be expressed as &id-expression. */
5983 {
5987 }
5990 }
5992 /* The next set of functions are used for providing helpful explanatory
5993 diagnostics for failed overload resolution. Their messages should be
5994 indented by two spaces for consistency with the messages in
5995 call.c */
5997 static int
5999 {
6001 }
6003 static int
6005 {
6010 }
6012 static int
6014 {
6016 }
6018 static int
6020 {
6026 }
6028 static int
6030 {
6034 }
6036 static int
6038 {
6041 " template parameter %qD is not a parameter pack, but "
6045 }
6047 static int
6049 {
6052 " template argument %qE does not match "
6056 }
6058 static int
6060 {
6064 }
6066 static int
6068 {
6074 }
6076 static int
6078 {
6080 {
6085 else
6087 " deduced conflicting values for non-type parameter "
6089 }
6091 }
6093 static int
6095 {
6098 " variable-sized array type %qT is not "
6100 arg);
6102 }
6104 static int
6106 {
6110 arg);
6112 }
6114 static int
6116 {
6118 {
6124 else
6129 }
6131 }
6133 static int
6135 {
6137 }
6139 static int
6142 {
6144 }
6146 static int
6149 {
6155 }
6157 static int
6160 {
6163 {
6171 }
6173 }
6175 static int
6177 {
6180 " template parameters of a template template argument are "
6183 }
6185 static int
6187 {
6193 }
6195 static int
6197 {
6202 }
6204 static int
6206 {
6210 arg);
6212 }
6214 /* Attempt to convert the non-type template parameter EXPR to the
6215 indicated TYPE. If the conversion is successful, return the
6216 converted value. If the conversion is unsuccessful, return
6217 NULL_TREE if we issued an error message, or error_mark_node if we
6218 did not. We issue error messages for out-and-out bad template
6219 parameters, but not simply because the conversion failed, since we
6220 might be just trying to do argument deduction. Both TYPE and EXPR
6221 must be non-dependent.
6223 The conversion follows the special rules described in
6224 [temp.arg.nontype], and it is much more strict than an implicit
6225 conversion.
6227 This function is called twice for each template argument (see
6228 lookup_template_class for a more accurate description of this
6229 problem). This means that we need to handle expressions which
6230 are not valid in a C++ source, but can be created from the
6231 first call (for instance, casts to perform conversions). These
6232 hacks can go away after we fix the double coercion problem. */
6234 static tree
6236 {
6237 tree expr_type;
6239 /* Detect immediately string literals as invalid non-type argument.
6240 This special-case is not needed for correctness (we would easily
6241 catch this later), but only to provide better diagnostic for this
6242 common user mistake. As suggested by DR 100, we do not mention
6243 linkage issues in the diagnostic as this is not the point. */
6244 /* FIXME we're making this OK. */
6246 {
6252 }
6254 /* Add the ADDR_EXPR now for the benefit of
6255 value_dependent_expression_p. */
6258 {
6262 }
6264 /* If we are in a template, EXPR may be non-dependent, but still
6265 have a syntactic, rather than semantic, form. For example, EXPR
6266 might be a SCOPE_REF, rather than the VAR_DECL to which the
6267 SCOPE_REF refers. Preserving the qualifying scope is necessary
6268 so that access checking can be performed when the template is
6269 instantiated -- but here we need the resolved form so that we can
6270 convert the argument. */
6283 else
6286 /* If the argument is non-dependent, perform any conversions in
6287 non-dependent context as well. */
6292 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6293 to a non-type argument of "nullptr". */
6297 /* In C++11, integral or enumeration non-type template arguments can be
6298 arbitrary constant expressions. Pointer and pointer to
6299 member arguments can be general constant expressions that evaluate
6300 to a null value, but otherwise still need to be of a specific form. */
6302 {
6304 /* A PTRMEM_CST is already constant, and a valid template
6305 argument for a parameter of pointer to member type, we just want
6306 to leave it in that form rather than lower it to a
6311 {
6315 {
6319 }
6320 }
6322 {
6327 }
6328 }
6330 /* HACK: Due to double coercion, we can get a
6331 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6332 which is the tree that we built on the first call (see
6333 below when coercing to reference to object or to reference to
6334 function). We just strip everything and get to the arg.
6335 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6336 for examples. */
6338 {
6344 {
6345 /* ??? Maybe we could use convert_from_reference here, but we
6346 would need to relax its constraints because the NOP_EXPR
6347 could actually change the type to something more cv-qualified,
6348 and this is not folded by convert_from_reference. */
6353 && (same_type_ignoring_top_level_qualifiers_p
6356 {
6359 }
6360 }
6361 }
6363 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6364 parameter is a pointer to object, through decay and
6365 qualification conversion. Let's strip everything. */
6367 {
6372 {
6373 /* Skip the ADDR_EXPR only if it is part of the decay for
6374 an array. Otherwise, it is part of the original argument
6375 in the source code. */
6380 }
6381 }
6383 /* [temp.arg.nontype]/5, bullet 1
6385 For a non-type template-parameter of integral or enumeration type,
6386 integral promotions (_conv.prom_) and integral conversions
6387 (_conv.integral_) are applied. */
6389 {
6398 /* Notice that there are constant expressions like '4 % 0' which
6399 do not fold into integer constants. */
6401 {
6403 {
6414 /* else cxx_constant_value complained but gave us
6415 a real constant, so go ahead. */
6417 }
6418 else
6420 }
6422 /* Avoid typedef problems. */
6425 }
6426 /* [temp.arg.nontype]/5, bullet 2
6428 For a non-type template-parameter of type pointer to object,
6429 qualification conversions (_conv.qual_) and the array-to-pointer
6430 conversion (_conv.array_) are applied. */
6432 {
6433 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6435 A template-argument for a non-type, non-template template-parameter
6436 shall be one of: [...]
6438 -- the name of a non-type template-parameter;
6439 -- the address of an object or function with external linkage, [...]
6440 expressed as "& id-expression" where the & is optional if the name
6441 refers to a function or array, or if the corresponding
6442 template-parameter is a reference.
6444 Here, we do not care about functions, as they are invalid anyway
6445 for a parameter of type pointer-to-object. */
6448 /* Non-type template parameters are OK. */
6449 ;
6454 {
6456 {
6459 "because %qD is a variable, not the address of "
6462 }
6464 {
6470 }
6471 /* Other values, like integer constants, might be valid
6472 non-type arguments of some other type. */
6474 }
6475 else
6476 {
6477 tree decl;
6482 {
6487 }
6489 {
6495 }
6497 {
6502 }
6503 }
6512 }
6513 /* [temp.arg.nontype]/5, bullet 3
6515 For a non-type template-parameter of type reference to object, no
6516 conversions apply. The type referred to by the reference may be more
6517 cv-qualified than the (otherwise identical) type of the
6518 template-argument. The template-parameter is bound directly to the
6519 template-argument, which must be an lvalue. */
6521 {
6523 expr_type))
6527 {
6532 }
6535 {
6540 }
6542 /* [temp.arg.nontype]/1
6544 A template-argument for a non-type, non-template template-parameter
6545 shall be one of: [...]
6547 -- the address of an object or function with external linkage. */
6550 {
6553 {
6556 "because a reference variable does not have a constant "
6559 }
6560 }
6563 {
6569 }
6571 /* DR 1155 allows internal linkage in C++11 and up. */
6574 {
6580 }
6583 }
6584 /* [temp.arg.nontype]/5, bullet 4
6586 For a non-type template-parameter of type pointer to function, only
6587 the function-to-pointer conversion (_conv.func_) is applied. If the
6588 template-argument represents a set of overloaded functions (or a
6589 pointer to such), the matching function is selected from the set
6590 (_over.over_). */
6592 {
6593 /* If the argument is a template-id, we might not have enough
6594 context information to decay the pointer. */
6596 {
6600 }
6603 /* Null pointer values are OK in C++11. */
6609 }
6610 /* [temp.arg.nontype]/5, bullet 5
6612 For a non-type template-parameter of type reference to function, no
6613 conversions apply. If the template-argument represents a set of
6614 overloaded functions, the matching function is selected from the set
6615 (_over.over_). */
6617 {
6619 {
6621 {
6626 }
6628 }
6635 }
6636 /* [temp.arg.nontype]/5, bullet 6
6638 For a non-type template-parameter of type pointer to member function,
6639 no conversions apply. If the template-argument represents a set of
6640 overloaded member functions, the matching member function is selected
6641 from the set (_over.over_). */
6643 {
6648 /* [temp.arg.nontype] bullet 1 says the pointer to member
6649 expression must be a pointer-to-member constant. */
6653 /* There is no way to disable standard conversions in
6654 resolve_address_of_overloaded_function (called by
6655 instantiate_type). It is possible that the call succeeded by
6656 converting &B::I to &D::I (where B is a base of D), so we need
6657 to reject this conversion here.
6659 Actually, even if there was a way to disable standard conversions,
6660 it would still be better to reject them here so that we can
6661 provide a superior diagnostic. */
6663 {
6665 {
6669 /* If we are just one standard conversion off, explain. */
6673 }
6675 }
6676 }
6677 /* [temp.arg.nontype]/5, bullet 7
6679 For a non-type template-parameter of type pointer to data member,
6680 qualification conversions (_conv.qual_) are applied. */
6682 {
6683 /* [temp.arg.nontype] bullet 1 says the pointer to member
6684 expression must be a pointer-to-member constant. */
6691 }
6693 {
6695 {
6700 }
6702 }
6703 /* A template non-type parameter must be one of the above. */
6704 else
6707 /* Sanity check: did we actually convert the argument to the
6708 right type? */
6712 }
6714 /* Subroutine of coerce_template_template_parms, which returns 1 if
6715 PARM_PARM and ARG_PARM match using the rule for the template
6716 parameters of template template parameters. Both PARM and ARG are
6717 template parameters; the rest of the arguments are the same as for
6718 coerce_template_template_parms.
6719 */
6720 static int
6722 tree arg,
6723 tsubst_flags_t complain,
6724 tree in_decl,
6725 tree outer_args)
6726 {
6735 {
6737 /* We encounter instantiations of templates like
6738 template <template <template <class> class> class TT>
6739 class C; */
6740 {
6747 }
6748 /* Fall through. */
6753 /* Argument is a parameter pack but parameter is not. */
6758 /* The tsubst call is used to handle cases such as
6760 template <int> class C {};
6761 template <class T, template <T> class TT> class D {};
6762 D<int, C> d;
6764 i.e. the parameter list of TT depends on earlier parameters. */
6766 {
6771 }
6775 /* Argument is a parameter pack but parameter is not. */
6782 }
6785 }
6788 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6789 template template parameters. Both PARM_PARMS and ARG_PARMS are
6790 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6791 or PARM_DECL.
6793 Consider the example:
6794 template <class T> class A;
6795 template<template <class U> class TT> class B;
6797 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6798 the parameters to A, and OUTER_ARGS contains A. */
6800 static int
6802 tree arg_parms,
6803 tsubst_flags_t complain,
6804 tree in_decl,
6805 tree outer_args)
6806 {
6817 /* Determine whether we have a parameter pack at the end of the
6818 template template parameter's template parameter list. */
6820 {
6827 {
6841 }
6842 }
6848 /* Check all of the template parameters except the parameter pack at
6849 the end (if any). */
6851 {
6860 outer_args))
6863 }
6866 {
6867 /* Check each of the template parameters in the template
6868 argument against the template parameter pack at the end of
6869 the template template parameter. */
6876 {
6883 outer_args))
6885 }
6886 }
6889 }
6891 /* Verifies that the deduced template arguments (in TARGS) for the
6892 template template parameters (in TPARMS) represent valid bindings,
6893 by comparing the template parameter list of each template argument
6894 to the template parameter list of its corresponding template
6895 template parameter, in accordance with DR150. This
6896 routine can only be called after all template arguments have been
6897 deduced. It will return TRUE if all of the template template
6898 parameter bindings are okay, FALSE otherwise. */
6899 bool
6901 {
6905 /* We're dealing with template parms in this process. */
6911 {
6916 {
6921 {
6922 /* Look inside the argument pack. */
6925 }
6928 {
6932 /* Extract the next argument from the argument
6933 pack. */
6937 /* Look at the pattern of the pack expansion. */
6940 /* Extract the template parameters from the template
6941 argument. */
6947 /* Verify that we can coerce the template template
6948 parameters from the template argument to the template
6949 parameter. This requires an exact match. */
6951 && !coerce_template_template_parms
6953 targ_parms,
6954 tf_none,
6955 tparm,
6956 targs))
6957 {
6960 }
6961 }
6962 }
6963 }
6965 out:
6969 }
6971 /* Since type attributes aren't mangled, we need to strip them from
6972 template type arguments. */
6974 static tree
6976 {
6986 }
6988 // A template declaration can be substituted for a constrained
6989 // template template parameter only when the argument is more
6990 // constrained than the parameter.
6991 static bool
6993 {
6996 /* For now, allow constrained template template arguments
6997 and unconstrained template template parameters. */
7003 // If the template parameter is constrained, we need to rewrite its
7004 // constraints in terms of the ARG's template parameters. This ensures
7005 // that all of the template parameter types will have the same depth.
7006 //
7007 // Note that this is only valid when coerce_template_template_parm is
7008 // true for the innermost template parameters of PARM and ARG. In other
7009 // words, because coercion is successful, this conversion will be valid.
7011 {
7018 }
7021 }
7023 // Convert a placeholder argument into a binding to the original
7024 // parameter. The original parameter is saved as the TREE_TYPE of
7025 // ARG.
7028 {
7031 }
7033 /* Convert the indicated template ARG as necessary to match the
7034 indicated template PARM. Returns the converted ARG, or
7035 error_mark_node if the conversion was unsuccessful. Error and
7036 warning messages are issued under control of COMPLAIN. This
7037 conversion is for the Ith parameter in the parameter list. ARGS is
7038 the full set of template arguments deduced so far. */
7040 static tree
7042 tree arg,
7043 tree args,
7044 tsubst_flags_t complain,
7046 tree in_decl)
7047 {
7048 tree orig_arg;
7049 tree val;
7055 /* Trivially convert placeholders. */
7061 {
7062 /* The template argument was the name of some
7063 member function. That's usually
7064 invalid, but static members are OK. In any
7065 case, grab the underlying fields/functions
7066 and issue an error later if required. */
7069 }
7077 /* When determining whether an argument pack expansion is a template,
7078 look at the pattern. */
7082 /* Deal with an injected-class-name used as a template template arg. */
7084 {
7087 {
7097 }
7098 }
7100 is_tmpl_type =
7116 {
7118 {
7122 }
7125 "to refer to a type member of a template parameter, "
7130 typename_type,
7131 complain);
7134 }
7136 {
7138 {
7140 {
7152 else
7155 }
7156 }
7158 }
7160 {
7162 {
7169 else
7172 }
7174 }
7177 {
7179 {
7183 /* The number of argument required is not known yet.
7184 Just accept it for now. */
7186 else
7187 {
7189 tree argparm;
7191 /* Strip alias templates that are equivalent to another
7192 template. */
7198 args))
7199 {
7202 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7203 TEMPLATE_DECL. */
7205 {
7210 }
7211 }
7212 else
7213 {
7215 {
7222 }
7225 }
7227 // Check that the constraints are compatible before allowing the
7228 // substitution.
7231 {
7233 {
7239 }
7241 }
7242 }
7243 }
7244 else
7246 /* We only form one instance of each template specialization.
7247 Therefore, if we use a non-canonical variant (i.e., a
7248 typedef), any future messages referring to the type will use
7249 the typedef, which is confusing if those future uses do not
7250 themselves also use the typedef. */
7253 }
7254 else
7255 {
7262 {
7265 else
7266 {
7267 /* Not sure if this is reachable, but it doesn't hurt
7268 to be robust. */
7271 }
7272 }
7275 /* We used to call digest_init here. However, digest_init
7276 will report errors, which we don't want when complain
7277 is zero. More importantly, digest_init will try too
7278 hard to convert things: for example, `0' should not be
7279 converted to pointer type at this point according to
7280 the standard. Accepting this is not merely an
7281 extension, since deciding whether or not these
7282 conversions can occur is part of determining which
7283 function template to call, or whether a given explicit
7284 argument specification is valid. */
7286 else
7287 {
7290 }
7298 {
7299 /* Reject template arguments that are references to built-in
7300 functions with no library fallbacks. */
7308 }
7311 {
7312 /* Strip typedefs from the SCOPE_REF. */
7315 complain);
7318 }
7319 }
7322 }
7324 /* Coerces the remaining template arguments in INNER_ARGS (from
7325 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7326 Returns the coerced argument pack. PARM_IDX is the position of this
7327 parameter in the template parameter list. ARGS is the original
7328 template argument list. */
7329 static tree
7332 tree args,
7333 tree inner_args,
7335 tree new_args,
7337 tree in_decl,
7338 tsubst_flags_t complain)
7339 {
7342 tree packed_args;
7343 tree argument_pack;
7350 {
7351 /* When the template parameter is a non-type template parameter pack
7352 or template template parameter pack whose type or template
7353 parameters use parameter packs, we know exactly how many arguments
7354 we are looking for. Build a vector of the instantiated decls for
7355 these template parameters in PACKED_PARMS. */
7356 /* We can't use make_pack_expansion here because it would interpret a
7357 _DECL as a use rather than a declaration. */
7371 /* If we're doing a partial instantiation of a member template,
7372 verify that all of the types used for the non-type
7373 template parameter pack are, in fact, valid for non-type
7374 template parameters. */
7377 {
7380 {
7384 }
7385 /* We don't know how many args we have yet, just
7386 use the unconverted ones for now. */
7388 }
7391 }
7392 /* Check if we have a placeholder pack, which indicates we're
7393 in the context of a introduction list. In that case we want
7394 to match this pack to the single placeholder. */
7398 {
7401 }
7402 else
7405 /* Convert the remaining arguments, which will be a part of the
7406 parameter pack "parm". */
7409 {
7415 {
7416 /* Once we've packed as many args as we have types, stop. */
7420 /* We don't know how many args we have yet, just
7421 use the unconverted ones for now. */
7423 else
7425 }
7428 {
7431 }
7432 else
7435 in_decl);
7439 }
7443 {
7448 }
7453 else
7454 {
7459 }
7466 }
7468 /* Returns the number of pack expansions in the template argument vector
7469 ARGS. */
7471 static int
7473 {
7478 {
7482 }
7484 }
7486 /* Convert all template arguments to their appropriate types, and
7487 return a vector containing the innermost resulting template
7488 arguments. If any error occurs, return error_mark_node. Error and
7489 warning messages are issued under control of COMPLAIN.
7491 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7492 for arguments not specified in ARGS. Otherwise, if
7493 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7494 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7495 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7496 ARGS. */
7498 static tree
7500 tree args,
7501 tree in_decl,
7502 tsubst_flags_t complain,
7505 {
7507 tree orig_inner_args;
7508 tree inner_args;
7509 tree new_args;
7510 tree new_inner_args;
7514 /* When used as a boolean value, indicates whether this is a
7515 variadic template parameter list. Since it's an int, we can also
7516 subtract it from nparms to get the number of non-variadic
7517 parameters. */
7522 /* Likewise for parameters with default arguments. */
7530 /* Determine if there are any parameter packs or default arguments. */
7532 {
7540 }
7543 /* If there are no parameters that follow a parameter pack, we need to
7544 expand any argument packs so that we can deduce a parameter pack from
7545 some non-packed args followed by an argument pack, as in variadic85.C.
7546 If there are such parameters, we need to leave argument packs intact
7547 so the arguments are assigned properly. This can happen when dealing
7548 with a nested class inside a partial specialization of a class
7549 template, as in variadic92.C, or when deducing a template parameter pack
7550 from a sub-declarator, as in variadic114.C. */
7554 /* Count any pack expansion args. */
7560 && require_all_args
7561 && !variadic_args_p
7562 && (!use_default_args
7565 {
7567 {
7569 {
7573 }
7574 else
7581 }
7584 }
7585 /* We can't pass a pack expansion to a non-pack parameter of an alias
7586 template (DR 1430). */
7590 && variadic_args_p
7592 {
7594 {
7596 {
7602 {
7605 "pack expansion argument for non-pack parameter "
7607 else
7609 "pack expansion argument for non-pack parameter "
7613 }
7614 }
7616 found:;
7617 }
7619 }
7621 /* We need to evaluate the template arguments, even though this
7622 template-id may be nested within a "sizeof". */
7631 {
7632 tree arg;
7633 tree parm;
7635 /* Get the Ith template parameter. */
7639 {
7642 }
7644 /* Calculate the next argument. */
7647 else
7652 {
7653 /* Some arguments will be placed in the
7654 template parameter pack PARM. */
7661 {
7662 /* We don't know how many args we have yet, just use the
7663 unconverted (and still packed) ones for now. */
7667 }
7671 /* Store this argument. */
7673 {
7674 lost++;
7675 /* We are done with all of the arguments. */
7677 }
7678 else
7679 {
7682 }
7685 }
7687 {
7689 {
7690 /* "If every valid specialization of a variadic template
7691 requires an empty template parameter pack, the template is
7692 ill-formed, no diagnostic required." So check that the
7693 pattern works with this parameter. */
7698 in_decl);
7700 {
7704 }
7706 /* Recover from missing typename. */
7710 /* We don't know how many args we have yet, just
7711 use the unconverted ones for now. */
7715 }
7716 }
7718 {
7719 /* There must be a default arg in this case. */
7722 /* The position of the first default template argument,
7723 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7724 Record that. */
7728 }
7729 else
7733 {
7736 }
7738 /* This only occurs if there was an error in the template
7739 parameter list itself (which we would already have
7740 reported) that we are trying to recover from, e.g., a class
7741 template with a parameter list such as
7742 template<typename..., typename>. */
7744 else
7750 lost++;
7752 }
7757 {
7759 {
7764 }
7766 }
7776 }
7778 /* Convert all template arguments to their appropriate types, and
7779 return a vector containing the innermost resulting template
7780 arguments. If any error occurs, return error_mark_node. Error and
7781 warning messages are not issued.
7783 Note that no function argument deduction is performed, and default
7784 arguments are used to fill in unspecified arguments. */
7785 tree
7787 {
7789 }
7791 /* Convert all template arguments to their appropriate type, and
7792 instantiate default arguments as needed. This returns a vector
7793 containing the innermost resulting template arguments, or
7794 error_mark_node if unsuccessful. */
7795 tree
7797 tsubst_flags_t complain)
7798 {
7800 }
7802 /* Like coerce_template_parms. If PARMS represents all template
7803 parameters levels, this function returns a vector of vectors
7804 representing all the resulting argument levels. Note that in this
7805 case, only the innermost arguments are coerced because the
7806 outermost ones are supposed to have been coerced already.
7808 Otherwise, if PARMS represents only (the innermost) vector of
7809 parameters, this function returns a vector containing just the
7810 innermost resulting arguments. */
7812 static tree
7814 tree args,
7815 tree in_decl,
7816 tsubst_flags_t complain,
7819 {
7822 tree coerced_args;
7825 {
7827 tree level;
7833 {
7834 tree l;
7838 require_all_args,
7839 use_default_args);
7840 else
7847 }
7848 }
7849 else
7852 require_all_args,
7853 use_default_args);
7855 }
7857 /* Returns 1 if template args OT and NT are equivalent. */
7859 int
7861 {
7868 /* For member templates */
7877 {
7894 }
7898 {
7901 /* Don't treat an alias template specialization with dependent
7902 arguments as equivalent to its underlying type when used as a
7903 template argument; we need them to be distinct so that we
7904 substitute into the specialization arguments at instantiation
7905 time. And aliases can't be equivalent without being ==, so
7906 we don't need to look any deeper. */
7909 else
7911 }
7914 else
7915 {
7916 /* Try to treat a template non-type argument that has been converted
7917 to the parameter type as equivalent to one that hasn't yet. */
7930 }
7931 }
7933 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7934 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7935 NEWARG_PTR with the offending arguments if they are non-NULL. */
7937 int
7940 {
7953 {
7958 {
7964 }
7965 }
7967 }
7969 static void
7971 {
7981 /* We are called both from instantiate_decl, where we've already had a
7982 tinst_level pushed, and instantiate_template, where we haven't.
7983 Compensate. */
7994 else
8003 }
8006 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8007 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8008 documentation for TEMPLATE_ID_EXPR. */
8010 tree
8012 {
8013 tree type;
8021 {
8024 }
8027 {
8029 unknown_type_node,
8031 arglist);
8033 }
8040 }
8042 /* Within the scope of a template class S<T>, the name S gets bound
8043 (in build_self_reference) to a TYPE_DECL for the class, not a
8044 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8045 or one of its enclosing classes, and that type is a template,
8046 return the associated TEMPLATE_DECL. Otherwise, the original
8047 DECL is returned.
8049 Also handle the case when DECL is a TREE_LIST of ambiguous
8050 injected-class-names from different bases. */
8052 tree
8054 {
8058 /* DR 176: A lookup that finds an injected-class-name (10.2
8059 [class.member.lookup]) can result in an ambiguity in certain cases
8060 (for example, if it is found in more than one base class). If all of
8061 the injected-class-names that are found refer to specializations of
8062 the same class template, and if the name is followed by a
8063 template-argument-list, the reference refers to the class template
8064 itself and not a specialization thereof, and is not ambiguous. */
8066 {
8069 {
8075 }
8078 else
8080 }
8086 }
8088 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8089 parameters, find the desired type.
8091 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8093 IN_DECL, if non-NULL, is the template declaration we are trying to
8094 instantiate.
8096 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8097 the class we are looking up.
8099 Issue error and warning messages under control of COMPLAIN.
8101 If the template class is really a local class in a template
8102 function, then the FUNCTION_CONTEXT is the function in which it is
8103 being instantiated.
8105 ??? Note that this function is currently called *twice* for each
8106 template-id: the first time from the parser, while creating the
8107 incomplete type (finish_template_type), and the second type during the
8108 real instantiation (instantiate_template_class). This is surely something
8109 that we want to avoid. It also causes some problems with argument
8110 coercion (see convert_nontype_argument for more information on this). */
8112 static tree
8115 {
8117 tree t;
8120 spec_entry elt;
8121 hashval_t hash;
8124 {
8128 else
8129 {
8136 }
8139 }
8141 {
8144 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8145 an implicit typename for the second A. Deal with it. */
8150 {
8153 }
8154 }
8157 {
8160 }
8162 {
8166 }
8168 {
8171 }
8173 /* Issue an error message if we didn't find a template. */
8175 {
8179 }
8182 /* Make sure it's a user visible template, if it was named by
8183 the user. */
8186 {
8188 {
8192 }
8194 }
8198 /* An alias that just changes the name of a template is equivalent to the
8199 other template, so if any of the arguments are pack expansions, strip
8200 the alias to avoid problems with a pack expansion passed to a non-pack
8201 alias template parameter (DR 1430). */
8206 {
8207 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8208 template arguments */
8210 tree parm;
8211 tree arglist2;
8212 tree outer;
8216 /* Consider an example where a template template parameter declared as
8218 template <class T, class U = std::allocator<T> > class TT
8220 The template parameter level of T and U are one level larger than
8221 of TT. To proper process the default argument of U, say when an
8222 instantiation `TT<int>' is seen, we need to build the full
8223 arguments containing {int} as the innermost level. Outer levels,
8224 available when not appearing as default template argument, can be
8225 obtained from the arguments of the enclosing template.
8227 Suppose that TT is later substituted with std::vector. The above
8228 instantiation is `TT<int, std::allocator<T> >' with TT at
8229 level 1, and T at level 2, while the template arguments at level 1
8230 becomes {std::vector} and the inner level 2 is {int}. */
8236 {
8237 /* This is an argument of the current template, so we haven't set
8238 DECL_CONTEXT yet. */
8239 tree relevant_template_parms;
8241 /* Parameter levels that are greater than the level of the given
8242 template template parm are irrelevant. */
8249 }
8255 complain,
8265 }
8266 else
8267 {
8269 tree gen_tmpl;
8270 tree type_decl;
8278 /* An error occurred while building the template TEMPL, and a
8279 diagnostic has most certainly been emitted for that
8280 already. Let's propagate that error. */
8289 {
8290 /* We've been given an incomplete set of template arguments.
8291 For example, given:
8293 template <class T> struct S1 {
8294 template <class U> struct S2 {};
8295 template <class U> struct S2<U*> {};
8296 };
8298 we will be called with an ARGLIST of `U*', but the
8299 TEMPLATE will be `template <class T> template
8300 <class U> struct S1<T>::S2'. We must fill in the missing
8301 arguments. */
8302 arglist
8304 arglist);
8306 }
8308 /* Now we should have enough arguments. */
8311 /* From here on, we're only interested in the most general
8312 template. */
8314 /* Calculate the BOUND_ARGS. These will be the args that are
8315 actually tsubst'd into the definition to create the
8316 instantiation. */
8318 complain,
8323 /* We were unable to bind the arguments. */
8326 /* In the scope of a template class, explicit references to the
8327 template class refer to the type of the template, not any
8328 instantiation of it. For example, in:
8330 template <class T> class C { void f(C<T>); }
8332 the `C<T>' is just the same as `C'. Outside of the
8333 class, however, such a reference is an instantiation. */
8337 /* comp_template_args is expensive, check it last. */
8339 arglist))
8342 /* If we already have this specialization, return it. */
8352 /* If the the template's constraints are not satisfied,
8353 then we cannot form a valid type.
8355 Note that the check is deferred until after the hash
8356 lookup. This prevents redundant checks on previously
8357 instantiated specializations. */
8359 {
8361 {
8364 }
8366 }
8370 /* If the deduced arguments are invalid, then the binding
8371 failed. */
8375 complain))
8382 {
8387 }
8397 /* Create the type. */
8399 {
8400 /* The user referred to a specialization of an alias
8401 template represented by GEN_TMPL.
8403 [temp.alias]/2 says:
8405 When a template-id refers to the specialization of an
8406 alias template, it is equivalent to the associated
8407 type obtained by substitution of its
8408 template-arguments for the template-parameters in the
8409 type-id of the alias template. */
8412 /* Note that the call above (by indirectly calling
8413 register_specialization in tsubst_decl) registers the
8414 TYPE_DECL representing the specialization of the alias
8415 template. So next time someone substitutes ARGLIST for
8416 the template parms into the alias template (GEN_TMPL),
8417 she'll get that TYPE_DECL back. */
8421 }
8423 {
8425 {
8436 }
8437 else
8438 {
8439 /* We don't want to call start_enum for this type, since
8440 the values for the enumeration constants may involve
8441 template parameters. And, no one should be interested
8442 in the enumeration constants for such a type. */
8445 }
8449 }
8451 {
8458 /* A local class. Make sure the decl gets registered properly. */
8463 /* This instantiation is another name for the primary
8464 template type. Set the TYPE_CANONICAL field
8465 appropriately. */
8468 /* Some of the template arguments require structural
8469 equality testing, so this template class requires
8470 structural equality testing. */
8472 }
8473 else
8476 /* If we called start_enum or pushtag above, this information
8477 will already be set up. */
8479 {
8486 }
8487 else
8491 {
8497 {
8500 }
8501 }
8505 {
8509 {
8510 tree attributes
8518 }
8519 }
8521 /* Let's consider the explicit specialization of a member
8522 of a class template specialization that is implicitly instantiated,
8523 e.g.:
8524 template<class T>
8525 struct S
8526 {
8527 template<class U> struct M {}; //#0
8528 };
8530 template<>
8531 template<>
8532 struct S<int>::M<char> //#1
8533 {
8534 int i;
8535 };
8536 [temp.expl.spec]/4 says this is valid.
8538 In this case, when we write:
8539 S<int>::M<char> m;
8541 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8542 the one of #0.
8544 When we encounter #1, we want to store the partial instantiation
8545 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8547 For all cases other than this "explicit specialization of member of a
8548 class template", we just want to store the most general template into
8549 the CLASSTYPE_TI_TEMPLATE of M.
8551 This case of "explicit specialization of member of a class template"
8552 only happens when:
8553 1/ the enclosing class is an instantiation of, and therefore not
8554 the same as, the context of the most general template, and
8555 2/ we aren't looking at the partial instantiation itself, i.e.
8556 the innermost arguments are not the same as the innermost parms of
8557 the most general template.
8559 So it's only when 1/ and 2/ happens that we want to use the partial
8560 instantiation of the member template in lieu of its most general
8561 template. */
8565 /* the enclosing class must be an instantiation... */
8568 {
8569 tree partial_inst_args;
8572 partial_inst_args =
8580 use_partial_inst_tmpl =
8581 /*...and we must not be looking at the partial instantiation
8582 itself. */
8584 partial_inst_args);
8585 }
8588 /* This case is easy; there are no member templates involved. */
8590 else
8591 {
8592 /* This is a full instantiation of a member template. Find
8593 the partial instantiation of which this is an instance. */
8595 /* Temporarily reduce by one the number of levels in the ARGLIST
8596 so as to avoid comparing the last set of arguments. */
8600 /* FOUND is either a proper class type, or an alias
8601 template specialization. In the later case, it's a
8602 TYPE_DECL, resulting from the substituting of arguments
8603 for parameters in the TYPE_DECL of the alias template
8604 done earlier. So be careful while getting the template
8605 of FOUND. */
8607 ? found
8611 }
8613 // Build template info for the new specialization.
8622 /* Note this use of the partial instantiation so we can check it
8623 later in maybe_process_partial_specialization. */
8630 /* Now that the type has been registered on the instantiations
8631 list, we set up the enumerators. Because the enumeration
8632 constants may involve the enumeration type itself, we make
8633 sure to register the type first, and then create the
8634 constants. That way, doing tsubst_expr for the enumeration
8635 constants won't result in recursive calls here; we'll find
8636 the instantiation and exit above. */
8640 /* If the type makes use of template parameters, the
8641 code that generates debugging information will crash. */
8644 /* Possibly limit visibility based on template args. */
8651 }
8652 }
8654 /* Wrapper for lookup_template_class_1. */
8656 tree
8659 {
8660 tree ret;
8666 }
8668 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8670 tree
8672 {
8673 /* The type of the expression is NULL_TREE since the template-id could refer
8674 to an explicit or partial specialization. */
8677 /* Except that concepts are always bool. */
8680 }
8682 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8684 tree
8686 {
8690 /* We never want to return a VAR_DECL for a variable concept, since they
8691 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8705 {
8707 {
8710 }
8712 }
8714 /* If a template-id refers to a specialization of a variable
8715 concept, then the expression is true if and only if the
8716 concept's constraints are satisfied by the given template
8717 arguments.
8719 NOTE: This is an extension of Concepts Lite TS that
8720 allows constraints to be used in expressions. */
8722 {
8725 }
8728 }
8730 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
8731 TARGS template args, and instantiate it if it's not dependent. */
8733 static tree
8735 tsubst_flags_t complain)
8736 {
8739 {
8742 }
8745 }
8747 \f
8748 struct pair_fn_data
8749 {
8750 tree_fn_t fn;
8752 /* True when we should also visit template parameters that occur in
8753 non-deduced contexts. */
8756 };
8758 /* Called from for_each_template_parm via walk_tree. */
8760 static tree
8762 {
8769 #define WALK_SUBTREE(NODE) \
8770 do \
8771 { \
8772 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
8773 pfd->include_nondeduced_p); \
8774 if (result) goto out; \
8775 } \
8776 while (0)
8783 {
8787 /* Fall through. */
8793 else
8803 /* Since we're not going to walk subtrees, we have to do this
8804 explicitly here. */
8806 /* Fall through. */
8809 /* Check the return type. */
8812 /* Check the parameter types. Since default arguments are not
8813 instantiated until they are needed, the TYPE_ARG_TYPES may
8814 contain expressions that involve template parameters. But,
8815 no-one should be looking at them yet. And, once they're
8816 instantiated, they don't contain template parameters, so
8817 there's no point in looking at them then, either. */
8818 {
8819 tree parm;
8824 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8825 want walk_tree walking into them itself. */
8827 }
8843 /* Fall through. */
8855 /* Record template parameters such as `T' inside `TT<T>'. */
8857 /* Fall through. */
8869 /* A template template parameter is encountered. */
8873 /* Already substituted template template parameter */
8878 /* A template-id in a TYPENAME_TYPE might be a deduced context after
8879 partial instantiation. */
8891 /* If there's no type, then this thing must be some expression
8892 involving template parameters. */
8914 }
8916 #undef WALK_SUBTREE
8918 /* We didn't find any template parameters we liked. */
8919 out:
8921 }
8923 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8924 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8925 call FN with the parameter and the DATA.
8926 If FN returns nonzero, the iteration is terminated, and
8927 for_each_template_parm returns 1. Otherwise, the iteration
8928 continues. If FN never returns a nonzero value, the value
8929 returned by for_each_template_parm is 0. If FN is NULL, it is
8930 considered to be the function which always returns 1.
8932 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8933 parameters that occur in non-deduced contexts. When false, only
8934 visits those template parameters that can be deduced. */
8936 static tree
8940 {
8942 tree result;
8944 /* Set up. */
8949 /* Walk the tree. (Conceptually, we would like to walk without
8950 duplicates, but for_each_template_parm_r recursively calls
8951 for_each_template_parm, so we would need to reorganize a fair
8952 bit to use walk_tree_without_duplicates, so we keep our own
8953 visited list.) */
8956 else
8959 for_each_template_parm_r,
8963 /* Clean up. */
8965 {
8968 }
8971 }
8973 /* Returns true if T depends on any template parameter. */
8975 int
8977 {
9007 else
9008 {
9011 }
9016 }
9018 /* Returns true iff current_function_decl is an incompletely instantiated
9019 template. Useful instead of processing_template_decl because the latter
9020 is set to 0 during instantiate_non_dependent_expr. */
9022 bool
9024 {
9033 }
9035 /* Returns true if T depends on any template parameter with level LEVEL. */
9037 bool
9039 {
9042 }
9044 /* Returns true if the signature of DECL depends on any template parameter from
9045 its enclosing class. */
9047 bool
9049 {
9059 template_parm_outer_level,
9069 }
9071 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9072 ill-formed translation unit, i.e. a variable or function that isn't
9073 usable in a constant expression. */
9077 {
9081 }
9083 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9084 neglectable and instantiated from within an erroneous instantiation. */
9086 static bool
9088 {
9099 }
9107 /* We're starting to instantiate D; record the template instantiation context
9108 for diagnostics and to restore it later. */
9110 bool
9112 {
9114 }
9116 /* We're starting to instantiate D; record the template instantiation context
9117 at LOC for diagnostics and to restore it later. */
9119 bool
9121 {
9125 {
9126 /* Tell error.c not to try to instantiate any templates. */
9129 "template instantiation depth exceeds maximum of %d"
9131 max_tinst_depth);
9133 }
9135 /* If the current instantiation caused problems, don't let it instantiate
9136 anything else. Do allow deduction substitution and decls usable in
9137 constant expressions. */
9154 }
9156 /* We're done instantiating this template; return to the instantiation
9157 context. */
9159 void
9161 {
9162 /* Restore the filename and line number stashed away when we started
9163 this instantiation. */
9167 }
9169 /* We're instantiating a deferred template; restore the template
9170 instantiation context in which the instantiation was requested, which
9171 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9173 static tree
9175 {
9187 }
9189 /* Returns the TINST_LEVEL which gives the original instantiation
9190 context. */
9194 {
9200 }
9202 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9203 vector of template arguments, as for tsubst.
9205 Returns an appropriate tsubst'd friend declaration. */
9207 static tree
9209 {
9210 tree new_friend;
9215 /* This was a friend declared with an explicit template
9216 argument list, e.g.:
9218 friend void f<>(T);
9220 to indicate that f was a template instantiation, not a new
9221 function declaration. Now, we have to figure out what
9222 instantiation of what template. */
9223 {
9225 tree new_args;
9226 tree tmpl;
9229 /* Friend functions are looked up in the containing namespace scope.
9230 We must enter that scope, to avoid finding member functions of the
9231 current class with same name. */
9246 tsk_none);
9248 }
9252 /* The NEW_FRIEND will look like an instantiation, to the
9253 compiler, but is not an instantiation from the point of view of
9254 the language. For example, we might have had:
9256 template <class T> struct S {
9257 template <class U> friend void f(T, U);
9258 };
9260 Then, in S<int>, template <class U> void f(int, U) is not an
9261 instantiation of anything. */
9267 {
9271 }
9273 /* The mangled name for the NEW_FRIEND is incorrect. The function
9274 is not a template instantiation and should not be mangled like
9275 one. Therefore, we forget the mangling here; we'll recompute it
9276 later if we need it. */
9278 {
9281 }
9284 {
9285 tree old_decl;
9286 tree new_friend_template_info;
9287 tree new_friend_result_template_info;
9288 tree ns;
9291 /* We must save some information from NEW_FRIEND before calling
9292 duplicate decls since that function will free NEW_FRIEND if
9293 possible. */
9295 new_friend_is_defn =
9300 {
9301 /* This declaration is a `primary' template. */
9304 new_friend_result_template_info
9306 }
9307 else
9310 /* Make the init_value nonzero so pushdecl knows this is a defn. */
9314 /* Inside pushdecl_namespace_level, we will push into the
9315 current namespace. However, the friend function should go
9316 into the namespace of the template. */
9326 {
9327 /* This new friend declaration matched an existing
9328 declaration. For example, given:
9330 template <class T> void f(T);
9331 template <class U> class C {
9332 template <class T> friend void f(T) {}
9333 };
9335 the friend declaration actually provides the definition
9336 of `f', once C has been instantiated for some type. So,
9337 old_decl will be the out-of-class template declaration,
9338 while new_friend is the in-class definition.
9340 But, if `f' was called before this point, the
9341 instantiation of `f' will have DECL_TI_ARGS corresponding
9342 to `T' but not to `U', references to which might appear
9343 in the definition of `f'. Previously, the most general
9344 template for an instantiation of `f' was the out-of-class
9345 version; now it is the in-class version. Therefore, we
9346 run through all specialization of `f', adding to their
9347 DECL_TI_ARGS appropriately. In particular, they need a
9348 new set of outer arguments, corresponding to the
9349 arguments for this class instantiation.
9351 The same situation can arise with something like this:
9353 friend void f(int);
9354 template <class T> class C {
9355 friend void f(T) {}
9356 };
9358 when `C<int>' is instantiated. Now, `f(int)' is defined
9359 in the class. */
9362 /* On the other hand, if the in-class declaration does
9363 *not* provide a definition, then we don't want to alter
9364 existing definitions. We can just leave everything
9365 alone. */
9366 ;
9367 else
9368 {
9372 /* Overwrite whatever template info was there before, if
9373 any, with the new template information pertaining to
9374 the declaration. */
9378 {
9379 /* We should have called reregister_specialization in
9380 duplicate_decls. */
9385 /* Instantiate it if the global has already been used. */
9389 }
9390 else
9391 {
9392 tree t;
9394 /* Indicate that the old function template is a partial
9395 instantiation. */
9403 /* Reassign any specializations already in the hash table
9404 to the new more general template, and add the
9405 additional template args. */
9409 {
9411 spec_entry elt;
9423 register_specialization
9426 }
9428 }
9429 }
9431 /* The information from NEW_FRIEND has been merged into OLD_DECL
9432 by duplicate_decls. */
9434 }
9435 }
9436 else
9437 {
9441 /* In the code
9442 template <class T> class C {
9443 template <class U> friend void C1<U>::f (); // case 1
9444 friend void C2<T>::f (); // case 2
9445 };
9446 we only need to make sure CONTEXT is a complete type for
9447 case 2. To distinguish between the two cases, we note that
9448 CONTEXT of case 1 remains dependent type after tsubst while
9449 this isn't true for case 2. */
9459 {
9461 /* do_friend adds the TEMPLATE_DECL for any member friend
9462 template even if it isn't a member template, i.e.
9463 template <class T> friend A<T>::f();
9464 Look through it in that case. */
9468 /* Check to see that the declaration is really present, and,
9469 possibly obtain an improved declaration. */
9474 }
9475 }
9478 }
9480 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9481 template arguments, as for tsubst.
9483 Returns an appropriate tsubst'd friend type or error_mark_node on
9484 failure. */
9486 static tree
9488 {
9489 tree friend_type;
9490 tree tmpl;
9491 tree context;
9494 {
9497 }
9502 {
9505 else
9507 }
9509 /* Look for a class template declaration. We look for hidden names
9510 because two friend declarations of the same template are the
9511 same. For example, in:
9513 struct A {
9514 template <typename> friend class F;
9515 };
9516 template <typename> struct B {
9517 template <typename> friend class F;
9518 };
9520 both F templates are the same. */
9524 /* But, if we don't find one, it might be because we're in a
9525 situation like this:
9527 template <class T>
9528 struct S {
9529 template <class U>
9530 friend struct S;
9531 };
9533 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9534 for `S<int>', not the TEMPLATE_DECL. */
9536 {
9539 }
9542 {
9543 /* The friend template has already been declared. Just
9544 check to see that the declarations match, and install any new
9545 default parameters. We must tsubst the default parameters,
9546 of course. We only need the innermost template parameters
9547 because that is all that redeclare_class_template will look
9548 at. */
9551 {
9552 tree parms;
9553 location_t saved_input_location;
9563 }
9566 }
9567 else
9568 {
9569 /* The friend template has not already been declared. In this
9570 case, the instantiation of the template class will cause the
9571 injection of this template into the global scope. */
9576 /* The new TMPL is not an instantiation of anything, so we
9577 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9578 the new type because that is supposed to be the corresponding
9579 template decl, i.e., TMPL. */
9586 /* Inject this template into the global scope. */
9588 }
9591 {
9594 else
9596 }
9599 }
9601 /* Returns zero if TYPE cannot be completed later due to circularity.
9602 Otherwise returns one. */
9604 static int
9606 {
9616 else
9618 }
9623 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9624 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9626 static tree
9629 {
9638 {
9645 clauses
9649 else
9651 }
9652 /* If the first attribute argument is an identifier, don't
9653 pass it through tsubst. Attributes like mode, format,
9654 cleanup and several target specific attributes expect it
9655 unmodified. */
9657 {
9658 tree chain
9663 }
9665 {
9666 /* An attribute pack expansion. */
9673 {
9677 }
9679 }
9680 else
9687 }
9689 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
9690 unchanged or a new TREE_LIST chain. */
9692 static tree
9695 {
9700 {
9704 }
9708 {
9711 {
9714 {
9716 do
9721 }
9722 }
9724 }
9727 }
9729 /* Apply any attributes which had to be deferred until instantiation
9730 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9731 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9733 static void
9736 {
9738 tree t;
9743 {
9747 }
9750 {
9754 }
9755 else
9759 {
9764 {
9767 {
9771 do
9774 }
9775 else
9777 }
9780 }
9781 }
9783 /* Perform (or defer) access check for typedefs that were referenced
9784 from within the template TMPL code.
9785 This is a subroutine of instantiate_decl and instantiate_class_template.
9786 TMPL is the template to consider and TARGS is the list of arguments of
9787 that template. */
9789 static void
9791 {
9792 location_t saved_location;
9803 {
9815 /* Make access check error messages point to the location
9816 of the use of the typedef. */
9820 tf_warning_or_error);
9821 }
9823 }
9825 static tree
9827 {
9829 tree typedecl;
9830 tree pbinfo;
9831 tree base_list;
9833 tree fn_context;
9842 /* Figure out which template is being instantiated. */
9846 /* Determine what specialization of the original template to
9847 instantiate. */
9850 {
9853 }
9855 {
9856 /* This TYPE is actually an instantiation of a partial
9857 specialization. We replace the innermost set of ARGS with
9858 the arguments appropriate for substitution. For example,
9859 given:
9861 template <class T> struct S {};
9862 template <class T> struct S<T*> {};
9864 and supposing that we are instantiating S<int*>, ARGS will
9865 presently be {int*} -- but we need {int}. */
9868 }
9869 else
9870 {
9873 }
9875 /* If the template we're instantiating is incomplete, then clearly
9876 there's nothing we can do. */
9880 /* If we've recursively instantiated too many templates, stop. */
9884 /* Now we're really doing the instantiation. Mark the type as in
9885 the process of being defined. */
9888 /* We may be in the middle of deferred access check. Disable
9889 it now. */
9896 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9901 else
9902 {
9905 }
9906 /* Use #pragma pack from the template context. */
9912 /* Set the input location to the most specialized template definition.
9913 This is needed if tsubsting causes an error. */
9925 {
9928 /* Adjust visibility for template arguments. */
9930 }
9936 /* We should never instantiate a nested class before its enclosing
9937 class; we need to look up the nested class by name before we can
9938 instantiate it, and that lookup should instantiate the enclosing
9939 class. */
9945 {
9946 tree pbase_binfo;
9947 tree pushed_scope;
9950 /* We must enter the scope containing the type, as that is where
9951 the accessibility of types named in dependent bases are
9952 looked up from. */
9955 /* Substitute into each of the bases to determine the actual
9956 basetypes. */
9958 {
9959 tree base;
9965 {
9966 expanded_bases =
9973 }
9976 {
9978 /* Extract the already-expanded base class. */
9980 else
9981 /* Substitute to figure out the base class. */
9983 NULL_TREE);
9991 }
9992 }
9994 /* The list is now in reverse order; correct that. */
9999 }
10000 /* Now call xref_basetypes to set up all the base-class
10001 information. */
10009 /* Now that our base classes are set up, enter the scope of the
10010 class, so that name lookups into base classes, etc. will work
10011 correctly. This is precisely analogous to what we do in
10012 begin_class_definition when defining an ordinary non-template
10013 class, except we also need to push the enclosing classes. */
10016 /* Now members are processed in the order of declaration. */
10019 {
10023 {
10025 {
10026 /* Build new CLASSTYPE_NESTED_UTDS. */
10028 tree newtag;
10034 /* If the member is a class template, then -- even after
10035 substitution -- there may be dependent types in the
10036 template argument list for the class. We increment
10037 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10038 that function will assume that no types are dependent
10039 when outside of a template. */
10049 {
10053 /* Unfortunately, lookup_template_class sets
10054 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10055 instantiation (i.e., for the type of a member
10056 template class nested within a template class.)
10057 This behavior is required for
10058 maybe_process_partial_specialization to work
10059 correctly, but is not accurate in this case;
10060 the TAG is not an instantiation of anything.
10061 (The corresponding TEMPLATE_DECL is an
10062 instantiation, but the TYPE is not.) */
10065 /* Now, we call pushtag to put this NEWTAG into the scope of
10066 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10067 pushtag calling push_template_decl. We don't have to do
10068 this for enums because it will already have been done in
10069 tsubst_enum. */
10073 }
10074 }
10076 {
10077 /* Build new TYPE_METHODS. */
10078 tree r;
10087 /* Instantiate members marked with attribute used. */
10093 }
10096 /* A closure type for a lambda in a default argument for a
10097 member template. Ignore it; it will be instantiated with
10099 else
10100 {
10101 /* Build new TYPE_FIELDS. */
10103 {
10104 tree condition;
10107 condition =
10117 }
10119 {
10120 tree r;
10124 /* The file and line for this declaration, to
10125 assist in error message reporting. Since we
10126 called push_tinst_level above, we don't need to
10127 restore these. */
10137 {
10138 /* A capture pack became multiple fields. */
10141 }
10144 {
10148 {
10149 /* In [temp.inst]:
10151 [t]he initialization (and any associated
10152 side-effects) of a static data member does
10153 not occur unless the static data member is
10154 itself used in a way that requires the
10155 definition of the static data member to
10156 exist.
10158 Therefore, we do not substitute into the
10159 initialized for the static data member here. */
10160 finish_static_data_member_decl
10166 /* Instantiate members marked with attribute used. */
10169 }
10171 {
10172 /* Determine whether R has a valid type and can be
10173 completed later. If R is invalid, then its type
10174 is replaced by error_mark_node. */
10180 {
10181 /* If R's type couldn't be completed and
10182 it isn't a flexible array member (whose
10183 type is incomplete by definition) give
10184 an error. */
10187 }
10188 }
10190 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10191 such a thing will already have been added to the field
10192 list by tsubst_enum in finish_member_declaration in the
10193 CLASSTYPE_NESTED_UTDS case above. */
10197 {
10200 }
10201 }
10202 }
10203 }
10204 }
10205 else
10206 {
10209 {
10210 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10216 {
10217 /* template <class T> friend class C; */
10220 }
10222 {
10223 /* template <class T> friend class C::D; */
10229 }
10232 {
10233 /* This could be either
10235 friend class T::C;
10237 when dependent_type_p is false or
10239 template <class U> friend class T::C;
10241 otherwise. */
10242 /* Bump processing_template_decl in case this is something like
10243 template <class T> friend struct A<T>::B. */
10250 }
10253 {
10254 /* friend class C;
10256 where C hasn't been declared yet. Let's lookup name
10257 from namespace scope directly, bypassing any name that
10258 come from dependent base class. */
10261 /* The call to xref_tag_from_type does injection for friend
10262 classes. */
10264 friend_type =
10268 }
10270 /* friend class C<T>; */
10273 /* Otherwise it's
10275 friend class C;
10277 where C is already declared or
10279 friend class C<int>;
10281 We don't have to do anything in these cases. */
10284 /* Trick make_friend_class into realizing that the friend
10285 we're adding is a template, not an ordinary class. It's
10286 important that we use make_friend_class since it will
10287 perform some error-checking and output cross-reference
10288 information. */
10296 }
10297 else
10298 {
10299 /* Build new DECL_FRIENDLIST. */
10300 tree r;
10302 /* The file and line for this declaration, to
10303 assist in error message reporting. Since we
10304 called push_tinst_level above, we don't need to
10305 restore these. */
10309 {
10312 }
10317 {
10320 }
10321 }
10322 }
10323 }
10326 {
10327 /* Restore these before substituting into the lambda capture
10328 initializers. */
10331 }
10334 {
10337 {
10343 {
10344 /* Set function_depth to avoid garbage collection. */
10348 }
10350 /* We need to instantiate the capture list from the template
10351 after we've instantiated the closure members, but before we
10352 consider adding the conversion op. Also keep any captures
10353 that may have been added during instantiation of the op(). */
10355 tree tmpl_cap
10364 }
10365 else
10367 }
10369 /* Set the file and line number information to whatever is given for
10370 the class itself. This puts error messages involving generated
10371 implicit functions at a predictable point, and the same point
10372 that would be used for non-template classes. */
10379 /* We don't instantiate default arguments for member functions. 14.7.1:
10381 The implicit instantiation of a class template specialization causes
10382 the implicit instantiation of the declarations, but not of the
10383 definitions or default arguments, of the class member functions,
10384 member classes, static data members and member templates.... */
10386 /* Some typedefs referenced from within the template code need to be access
10387 checked at template instantiation time, i.e now. These types were
10388 added to the template at parsing time. Let's get those and perform
10389 the access checks then. */
10399 /* The vtable for a template class can be emitted in any translation
10400 unit in which the class is instantiated. When there is no key
10401 method, however, finish_struct_1 will already have added TYPE to
10402 the keyed_classes list. */
10407 }
10409 /* Wrapper for instantiate_class_template_1. */
10411 tree
10413 {
10414 tree ret;
10419 }
10421 static tree
10423 {
10424 tree r;
10430 else
10431 {
10438 }
10440 }
10442 /* Given a function parameter pack TMPL_PARM and some function parameters
10443 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10444 and set *SPEC_P to point at the next point in the list. */
10446 tree
10448 {
10449 /* Collect all of the extra "packed" parameters into an
10450 argument pack. */
10451 tree parmvec;
10452 tree parmtypevec;
10463 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10468 {
10471 }
10473 /* Build the argument packs. */
10480 }
10482 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10483 NONTYPE_ARGUMENT_PACK. */
10485 static tree
10487 {
10489 }
10491 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10492 pack expansion with no extra args, 2 if it has extra args, or 0
10493 if it is not a pack expansion. */
10495 static int
10497 {
10503 /* A decl pack is itself an expansion. */
10510 }
10513 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10515 static tree
10517 {
10524 }
10526 /* This is a subroutine of tsubst_pack_expansion.
10528 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10529 mechanism to store the (non complete list of) arguments of the
10530 substitution and return a non substituted pack expansion, in order
10531 to wait for when we have enough arguments to really perform the
10532 substitution. */
10534 static bool
10538 {
10539 /* If one pack has an expansion and another pack has a normal
10540 argument or if one pack has an empty argument and an another
10541 one hasn't then tsubst_pack_expansion cannot perform the
10542 substitution and need to fall back on the
10543 PACK_EXPANSION_EXTRA mechanism. */
10551 {
10554 parm_pack;
10556 {
10561 /* We can't substitute a pack expansion with extra args into
10562 our pattern. */
10566 else
10568 }
10572 }
10574 }
10576 /* [temp.variadic]/6 says that:
10578 The instantiation of a pack expansion [...]
10579 produces a list E1,E2, ..., En, where N is the number of elements
10580 in the pack expansion parameters.
10582 This subroutine of tsubst_pack_expansion produces one of these Ei.
10584 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10585 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10586 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10587 INDEX is the index 'i' of the element Ei to produce. ARGS,
10588 COMPLAIN, and IN_DECL are the same parameters as for the
10589 tsubst_pack_expansion function.
10591 The function returns the resulting Ei upon successful completion,
10592 or error_mark_node.
10594 Note that this function possibly modifies the ARGS parameter, so
10595 it's the responsibility of the caller to restore it. */
10597 static tree
10599 tree parm_packs,
10601 tree args /* This parm gets
10603 tsubst_flags_t complain,
10604 tree in_decl)
10605 {
10606 tree t;
10609 /* For each parameter pack, change the substitution of the parameter
10610 pack to the ith argument in its argument pack, then expand the
10611 pattern. */
10613 {
10618 ith_elem_is_expansion |=
10621 /* Select the Ith argument from the pack. */
10624 {
10626 {
10631 }
10632 else
10634 }
10635 else
10636 {
10641 {
10643 /* Update the corresponding argument. */
10645 }
10646 else
10647 /* Re-use the ARGUMENT_PACK_SELECT. */
10649 }
10651 }
10653 /* Substitute into the PATTERN with the (possibly altered)
10654 arguments. */
10656 /* Expanding a fixed parameter pack from
10657 coerce_template_parameter_pack. */
10662 {
10665 else
10668 }
10672 else
10675 /* If the Ith argument pack element is a pack expansion, then
10676 the Ith element resulting from the substituting is going to
10677 be a pack expansion as well. */
10682 }
10684 /* When the unexpanded parameter pack in a fold expression expands to an empty
10685 sequence, the value of the expression is as follows; the program is
10686 ill-formed if the operator is not listed in this table.
10688 && true
10689 || false
10690 , void() */
10692 tree
10694 {
10698 {
10707 }
10713 }
10715 /* Given a fold-expression T and a current LEFT and RIGHT operand,
10716 form an expression that combines the two terms using the
10717 operator of T. */
10719 static tree
10721 {
10725 // Handle compound assignment operators.
10730 {
10740 complain);
10741 }
10742 }
10744 /* Substitute ARGS into the pack of a fold expression T. */
10748 {
10750 }
10752 /* Substitute ARGS into the pack of a fold expression T. */
10756 {
10758 }
10760 /* Expand a PACK of arguments into a grouped as left fold.
10761 Given a pack containing elements A0, A1, ..., An and an
10762 operator @, this builds the expression:
10764 ((A0 @ A1) @ A2) ... @ An
10766 Note that PACK must not be empty.
10768 The operator is defined by the original fold expression T. */
10770 static tree
10772 {
10775 {
10778 }
10780 }
10782 /* Substitute into a unary left fold expression. */
10784 static tree
10786 tree in_decl)
10787 {
10792 {
10796 }
10799 else
10801 }
10803 /* Substitute into a binary left fold expression.
10805 Do ths by building a single (non-empty) vector of argumnts and
10806 building the expression from those elements. */
10808 static tree
10810 tree in_decl)
10811 {
10820 {
10825 }
10833 }
10835 /* Expand a PACK of arguments into a grouped as right fold.
10836 Given a pack containing elementns A0, A1, ..., and an
10837 operator @, this builds the expression:
10839 A0@ ... (An-2 @ (An-1 @ An))
10841 Note that PACK must not be empty.
10843 The operator is defined by the original fold expression T. */
10845 tree
10847 {
10848 // Build the expression.
10852 {
10855 }
10857 }
10859 /* Substitute into a unary right fold expression. */
10861 static tree
10863 tree in_decl)
10864 {
10869 {
10873 }
10876 else
10878 }
10880 /* Substitute into a binary right fold expression.
10882 Do ths by building a single (non-empty) vector of arguments and
10883 building the expression from those elements. */
10885 static tree
10887 tree in_decl)
10888 {
10897 {
10902 }
10911 }
10914 /* Substitute ARGS into T, which is an pack expansion
10915 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
10916 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
10917 (if only a partial substitution could be performed) or
10918 ERROR_MARK_NODE if there was an error. */
10919 tree
10921 tree in_decl)
10922 {
10923 tree pattern;
10927 tree result;
10935 /* Add in any args remembered from an earlier partial instantiation. */
10940 /* Determine the argument packs that will instantiate the parameter
10941 packs used in the expansion expression. While we're at it,
10942 compute the number of arguments to be expanded and make sure it
10943 is consistent. */
10946 {
10953 {
10957 else
10960 }
10962 {
10963 /* We know we have correct local_specializations if this
10964 expansion is at function scope, or if we're dealing with a
10965 local parameter in a requires expression; for the latter,
10966 tsubst_requires_expr set it up appropriately. */
10969 else
10970 /* We can't rely on local_specializations for a parameter
10971 name used later in a function declaration (such as in a
10972 late-specified return type). Even if it exists, it might
10973 have the wrong value for a recursive call. */
10977 {
10978 /* This parameter pack was used in an unevaluated context. Just
10979 make a dummy decl, since it's only used for its type. */
10982 /* Partial instantiation of the parm_pack, we can't build
10983 up an argument pack yet. */
10985 else
10987 }
10988 }
10991 else
10992 {
10998 }
11005 /* This can only happen if we forget to expand an argument
11006 pack somewhere else. Just return an error, silently. */
11007 {
11011 }
11014 {
11018 /* Don't bother trying to do a partial substitution with
11019 incomplete packs; we'll try again after deduction. */
11026 {
11032 pattern);
11033 else
11036 pattern);
11038 }
11040 /* Keep track of the parameter packs and their corresponding
11041 argument packs. */
11044 }
11045 else
11046 {
11047 /* We can't substitute for this parameter pack. We use a flag as
11048 well as the missing_level counter because function parameter
11049 packs don't have a level. */
11052 }
11053 }
11055 /* If the expansion is just T..., return the matching argument pack, unless
11056 we need to call convert_from_reference on all the elements. This is an
11057 important optimization; see c++/68422. */
11060 {
11062 /* Types need no adjustment, nor does sizeof..., and if we still have
11063 some pack expansion args we won't do anything yet. */
11068 /* Also optimize expression pack expansions if we can tell that the
11069 elements won't have reference type. */
11075 /* Otherwise use the normal path so we get convert_from_reference. */
11076 }
11078 /* We cannot expand this expansion expression, because we don't have
11079 all of the argument packs we need. */
11081 {
11082 /* We got some full packs, but we can't substitute them in until we
11083 have values for all the packs. So remember these until then. */
11088 }
11090 {
11091 /* There were no real arguments, we're just replacing a parameter
11092 pack with another version of itself. Substitute into the
11093 pattern and return a PACK_EXPANSION_*. The caller will need to
11094 deal with that. */
11098 else
11102 }
11107 {
11108 /* We're in a late-specified return type, so create our own local
11109 specializations map; the current map is either NULL or (in the
11110 case of recursive unification) might have bindings that we don't
11111 want to use or alter. */
11114 }
11116 /* For each argument in each argument pack, substitute into the
11117 pattern. */
11121 {
11123 i,
11125 in_decl);
11128 {
11131 }
11132 }
11134 /* Update ARGS to restore the substitution from parameter packs to
11135 their argument packs. */
11137 {
11143 else
11144 {
11152 /* Update the corresponding argument. */
11156 else
11158 }
11159 }
11162 {
11165 }
11167 /* If the dependent pack arguments were such that we end up with only a
11168 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11174 }
11176 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11177 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11178 parameter packs; all parms generated from a function parameter pack will
11179 have the same DECL_PARM_INDEX. */
11181 tree
11183 {
11185 tree patparm;
11188 {
11194 }
11195 else
11196 {
11201 }
11204 }
11206 /* Make an argument pack out of the TREE_VEC VEC. */
11208 static tree
11210 {
11211 tree pack;
11215 else
11216 {
11220 }
11223 }
11225 /* Return an exact copy of template args T that can be modified
11226 independently. */
11228 static tree
11230 {
11238 {
11243 }
11249 }
11251 /* Substitute ARGS into the vector or list of template arguments T. */
11253 static tree
11255 {
11267 {
11269 tree new_arg;
11274 {
11275 /* Substitute into an expansion expression. */
11279 /* Add to the expanded length adjustment the number of
11280 expanded arguments. We subtract one from this
11281 measurement, because the argument pack expression
11282 itself is already counted as 1 in
11283 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11284 the argument pack is empty. */
11286 }
11288 {
11289 /* Substitute into each of the arguments. */
11295 new_arg,
11309 }
11310 }
11311 else
11320 }
11325 /* Make space for the expanded arguments coming from template
11326 argument packs. */
11328 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11329 arguments for a member template.
11330 In that case each TREE_VEC in ORIG_T represents a level of template
11331 arguments, and ORIG_T won't carry any non defaulted argument count.
11332 It will rather be the nested TREE_VECs that will carry one.
11333 In other words, ORIG_T carries a non defaulted argument count only
11334 if it doesn't contain any nested TREE_VEC. */
11336 {
11340 }
11342 {
11346 {
11349 /* Now expand the template argument pack "in place". */
11352 }
11353 else
11354 {
11356 out++;
11357 }
11358 }
11361 }
11363 /* Return the result of substituting ARGS into the template parameters
11364 given by PARMS. If there are m levels of ARGS and m + n levels of
11365 PARMS, then the result will contain n levels of PARMS. For
11366 example, if PARMS is `template <class T> template <class U>
11367 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11368 result will be `template <int*, double, class V>'. */
11370 static tree
11372 {
11376 /* When substituting into a template, we must set
11377 PROCESSING_TEMPLATE_DECL as the template parameters may be
11378 dependent if they are based on one-another, and the dependency
11379 predicates are short-circuit outside of templates. */
11386 {
11387 tree new_vec =
11392 {
11393 tree tuple;
11405 }
11411 }
11416 }
11418 /* Return the result of substituting ARGS into one template parameter
11419 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11420 parameter and which TREE_PURPOSE is the default argument of the
11421 template parameter. */
11423 static tree
11425 {
11446 }
11448 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11449 type T. If T is not an aggregate or enumeration type, it is
11450 handled as if by tsubst. IN_DECL is as for tsubst. If
11451 ENTERING_SCOPE is nonzero, T is the context for a template which
11452 we are presently tsubst'ing. Return the substituted value. */
11454 static tree
11456 tree args,
11457 tsubst_flags_t complain,
11458 tree in_decl,
11460 {
11465 {
11470 /* Fall through. */
11474 {
11475 tree argvec;
11476 tree context;
11477 tree r;
11481 /* In "sizeof(X<I>)" we need to evaluate "I". */
11487 /* First, determine the context for the type we are looking
11488 up. */
11491 {
11494 /* If context is a nested class inside a class template,
11495 it may still need to be instantiated (c++/33959). */
11497 }
11499 /* Then, figure out what arguments are appropriate for the
11500 type we are trying to find. For example, given:
11502 template <class T> struct S;
11503 template <class T, class U> void f(T, U) { S<U> su; }
11505 and supposing that we are instantiating f<int, double>,
11506 then our ARGS will be {int, double}, but, when looking up
11507 S we only want {double}. */
11512 else
11513 {
11517 }
11523 }
11524 else
11525 /* This is not a template type, so there's nothing to do. */
11530 }
11531 }
11533 /* Substitute into the default argument ARG (a default argument for
11534 FN), which has the indicated TYPE. */
11536 tree
11538 {
11543 /* This can happen in invalid code. */
11547 /* This default argument came from a template. Instantiate the
11548 default argument here, not in tsubst. In the case of
11549 something like:
11551 template <class T>
11552 struct S {
11553 static T t();
11554 void f(T = t());
11555 };
11557 we must be careful to do name lookup in the scope of S<T>,
11558 rather than in the current class. */
11560 /* The "this" pointer is not valid in a default argument. */
11562 {
11567 }
11570 /* The default argument expression may cause implicitly defined
11571 member functions to be synthesized, which will result in garbage
11572 collection. We must treat this situation as if we were within
11573 the body of function so as to avoid collecting live data on the
11574 stack. */
11582 /* Restore the "this" pointer. */
11584 {
11587 }
11594 /* Make sure the default argument is reasonable. */
11600 }
11602 /* Substitute into all the default arguments for FN. */
11604 static void
11606 {
11607 tree arg;
11608 tree tmpl_args;
11612 /* If this function is not yet instantiated, we certainly don't need
11613 its default arguments. */
11616 /* Don't do this again for clones. */
11621 arg;
11627 complain);
11628 }
11630 /* Substitute the ARGS into the T, which is a _DECL. Return the
11631 result of the substitution. Issue error and warning messages under
11632 control of COMPLAIN. */
11634 static tree
11636 {
11637 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11638 location_t saved_loc;
11643 /* Set the filename and linenumber to improve error-reporting. */
11648 {
11650 {
11651 /* We can get here when processing a member function template,
11652 member class template, or template template parameter. */
11654 tree spec;
11655 tree tmpl_args;
11656 tree full_args;
11659 {
11660 /* Template template parameter is treated here. */
11664 /* If we get a real template back, return it. This can happen in
11665 the context of most_specialized_partial_spec. */
11668 else
11669 /* The new TEMPLATE_DECL was built in
11670 reduce_template_parm_level. */
11673 }
11675 /* We might already have an instance of this template.
11676 The ARGS are for the surrounding class type, so the
11677 full args contain the tsubst'd args for the context,
11678 plus the innermost args from the template decl. */
11682 /* Because this is a template, the arguments will still be
11683 dependent, even after substitution. If
11684 PROCESSING_TEMPLATE_DECL is not set, the dependency
11685 predicates will short-circuit. */
11693 /* If this is a default template template argument,
11694 tsubst might not have changed anything. */
11701 {
11704 }
11706 /* Make a new template decl. It will be similar to the
11707 original, but will record the current template arguments.
11708 We also create a new function declaration, which is just
11709 like the old one, but points to this new template, rather
11710 than the old one. */
11715 // Build new template info linking to the original template decl.
11720 {
11721 tree new_type;
11729 /* For a partial specialization, we need to keep pointing to
11730 the primary template. */
11736 }
11737 else
11738 {
11739 tree new_decl;
11751 }
11757 /* The template parameters for this new template are all the
11758 template parameters for the old template, except the
11759 outermost level of parameters. */
11762 complain);
11768 /* Record this non-type partial instantiation. */
11772 }
11776 {
11777 tree ctx;
11780 tree gen_tmpl;
11781 tree type;
11786 /* Nobody should be tsubst'ing into non-template functions. */
11790 {
11791 tree spec;
11793 /* If T is not dependent, just return it. */
11797 /* Calculate the most general template of which R is a
11798 specialization, and the complete set of arguments used to
11799 specialize R. */
11802 (DECL_TEMPLATE_RESULT
11808 /* Check to see if we already have this specialization. */
11813 {
11816 }
11818 /* We can see more levels of arguments than parameters if
11819 there was a specialization of a member template, like
11820 this:
11822 template <class T> struct S { template <class U> void f(); }
11823 template <> template <class U> void S<int>::f(U);
11825 Here, we'll be substituting into the specialization,
11826 because that's where we can find the code we actually
11827 want to generate, but we'll have enough arguments for
11828 the most general template.
11830 We also deal with the peculiar case:
11832 template <class T> struct S {
11833 template <class U> friend void f();
11834 };
11835 template <class U> void f() {}
11836 template S<int>;
11837 template void f<double>();
11839 Here, the ARGS for the instantiation of will be {int,
11840 double}. But, we only need as many ARGS as there are
11841 levels of template parameters in CODE_PATTERN. We are
11842 careful not to get fooled into reducing the ARGS in
11843 situations like:
11845 template <class T> struct S { template <class U> void f(U); }
11846 template <class T> template <> void S<T>::f(int) {}
11848 which we can spot because the pattern will be a
11849 specialization in this case. */
11851 parms_depth =
11856 }
11857 else
11858 {
11859 /* This special case arises when we have something like this:
11861 template <class T> struct S {
11862 friend void f<int>(int, double);
11863 };
11865 Here, the DECL_TI_TEMPLATE for the friend declaration
11866 will be an IDENTIFIER_NODE. We are being called from
11867 tsubst_friend_function, and we want only to create a
11868 new decl (R) with appropriate types so that we can call
11869 determine_specialization. */
11871 }
11874 {
11877 else
11881 }
11882 else
11883 {
11886 }
11891 /* If we hit excessive deduction depth, the type is bogus even if
11892 it isn't error_mark_node, so don't build a decl. */
11896 /* We do NOT check for matching decls pushed separately at this
11897 point, as they may not represent instantiations of this
11898 template, and in any case are considered separate under the
11899 discrete model. */
11903 /* Clear out the mangled name and RTL for the instantiation. */
11906 /* Leave DECL_INITIAL set on deleted instantiations. */
11911 /* OpenMP UDRs have the only argument a reference to the declared
11912 type. We want to diagnose if the declared type is a reference,
11913 which is invalid, but as references to references are usually
11914 quietly merged, diagnose it here. */
11916 {
11917 tree argtype
11922 "reference type %qT in "
11926 argtype);
11927 }
11930 /* Type-conversion operator. Reconstruct the name, in
11931 case it's the name of one of the template's parameters. */
11941 /* If this is an instantiation of a function with internal
11942 linkage, we already know what object file linkage will be
11943 assigned to the instantiation. */
11952 /* We'll re-clone as appropriate in instantiate_template. */
11955 /* If we aren't complaining now, return on error before we register
11956 the specialization so that we'll complain eventually. */
11962 /* When instantiating a constrained member, substitute
11963 into the constraints to create a new constraint. */
11966 {
11969 }
11971 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
11972 this in the special friend case mentioned above where
11973 GEN_TMPL is NULL. */
11975 {
11980 tree new_r
11983 /* We instantiated this while substituting into
11984 the type earlier (template/friend54.C). */
11987 /* We're not supposed to instantiate default arguments
11988 until they are called, for a template. But, for a
11989 declaration like:
11991 template <class T> void f ()
11992 { extern void g(int i = T()); }
11994 we should do the substitution when the template is
11995 instantiated. We handle the member function case in
11996 instantiate_class_template since the default arguments
11997 might refer to other members of the class. */
12002 }
12003 else
12006 /* Copy the list of befriending classes. */
12010 {
12014 in_decl);
12015 }
12018 {
12024 /* If this is an instantiation of a member template, clone it.
12025 If it isn't, that'll be handled by
12026 clone_constructors_and_destructors. */
12029 }
12040 /* Possibly limit visibility based on template args. */
12043 {
12047 }
12055 }
12059 {
12067 {
12068 /* If there is a local specialization that isn't a
12069 parameter pack, it means that we're doing a "simple"
12070 substitution from inside tsubst_pack_expansion. Just
12071 return the local specialization (which will be a single
12072 parm). */
12079 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12080 the parameters in this function parameter pack. */
12084 {
12087 /* Zero-length parameter packs are boring. Just substitute
12088 into the chain. */
12092 }
12093 else
12094 {
12095 /* All we did was update the type. Make a note of that. */
12098 }
12099 }
12101 /* Loop through all of the parameters we'll build. When T is
12102 a function parameter pack, LEN is the number of expanded
12103 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12106 {
12113 /* We're on the Ith parameter of the function parameter
12114 pack. */
12115 {
12116 /* Get the Ith type. */
12119 /* Rename the parameter to include the index. */
12122 }
12124 /* We're dealing with a normal parameter. */
12132 {
12135 else
12138 }
12148 /* Keep track of the first new parameter we
12149 generate. That's what will be returned to the
12150 caller. */
12154 /* Build a proper chain of parameters when substituting
12155 into a function parameter pack. */
12158 }
12160 /* If cp_unevaluated_operand is set, we're just looking for a
12161 single dummy parameter, so don't keep going. */
12166 /* FIRST_R contains the start of the chain we've built. */
12168 }
12172 {
12179 {
12180 /* This field is a lambda capture pack. Return a TREE_VEC of
12181 the expanded fields to instantiate_class_template_1 and
12182 store them in the specializations hash table as a
12183 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12187 {
12190 }
12191 else
12192 {
12193 /* All we did was update the type. Make a note of that. */
12196 }
12197 }
12200 {
12203 {
12207 }
12217 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12218 non-bit-fields DECL_INITIAL is a non-static data member
12219 initializer, which gets deferred instantiation. */
12225 {
12226 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12227 NSDMI in perform_member_init. Still set DECL_INITIAL
12228 so that we know there is one. */
12233 }
12234 /* We don't have to set DECL_CONTEXT here; it is set by
12235 finish_member_declaration. */
12243 }
12246 {
12254 }
12255 }
12259 /* We reach here only for member using decls. We also need to check
12260 uses_template_parms because DECL_DEPENDENT_P is not set for a
12261 using-declaration that designates a member of the current
12262 instantiation (c++/53549). */
12265 {
12272 else
12273 {
12276 }
12277 }
12278 else
12279 {
12282 }
12287 {
12290 tree spec;
12292 tree ctx;
12301 {
12302 /* If this is the canonical decl, we don't have to
12303 mess with instantiations, and often we can't (for
12304 typename, template type parms and such). Note that
12305 TYPE_NAME is not correct for the above test if
12306 we've copied the type for a typedef. */
12312 }
12314 /* Check to see if we already have the specialization we
12315 need. */
12318 {
12319 /* T is a static data member or namespace-scope entity.
12320 We have to substitute into namespace-scope variables
12321 (not just variable templates) because of cases like:
12323 template <class T> void f() { extern T t; }
12325 where the entity referenced is not known until
12326 instantiation time. */
12330 {
12332 complain,
12334 /* If CTX is unchanged, then T is in fact the
12335 specialization we want. That situation occurs when
12336 referencing a static data member within in its own
12337 class. We can use pointer equality, rather than
12338 same_type_p, because DECL_CONTEXT is always
12339 canonical... */
12341 /* ... unless T is a member template; in which
12342 case our caller can be willing to create a
12343 specialization of that template represented
12344 by T. */
12348 }
12351 {
12356 argvec = (coerce_innermost_template_parms
12364 }
12365 }
12366 else
12367 {
12368 /* A local variable. */
12370 /* Subsequent calls to pushdecl will fill this in. */
12372 /* Unless this is a reference to a static variable from an
12373 enclosing function, in which case we need to fill it in now. */
12375 {
12379 }
12381 }
12382 /* If we already have the specialization we need, there is
12383 nothing more to do. */
12385 {
12388 }
12390 /* Create a new node for the specialization we need. */
12393 {
12396 else
12403 }
12405 {
12406 /* Even if the original location is out of scope, the
12407 newly substituted one is not. */
12414 {
12415 /* It may seem that this case cannot occur, since:
12417 typedef void f();
12418 void g() { f x; }
12420 declares a function, not a variable. However:
12422 typedef void f();
12423 template <typename T> void g() { T t; }
12424 template void g<f>();
12426 is an attempt to declare a variable with function
12427 type. */
12429 /* R is not yet sufficiently initialized, so we
12430 just use its name. */
12433 }
12435 /* Wait until cp_finish_decl to set this again, to handle
12436 circular dependency (template/instantiate6.C). */
12441 {
12446 {
12449 }
12451 }
12455 }
12461 /* Clear out the mangled name and RTL for the instantiation. */
12465 /* The initializer must not be expanded until it is required;
12466 see [temp.inst]. */
12474 {
12475 /* Possibly limit visibility based on template args. */
12478 {
12482 }
12484 }
12487 {
12488 /* A static data member declaration is always marked
12489 external when it is declared in-class, even if an
12490 initializer is present. We mimic the non-template
12491 processing here. */
12499 }
12500 else
12501 {
12506 }
12514 /* Preserve a typedef that names a type. */
12516 {
12520 /* An alias template specialization can be dependent
12521 even if its underlying type is not. */
12523 }
12526 }
12531 }
12532 #undef RETURN
12534 out:
12535 /* Restore the file and line information. */
12539 }
12541 /* Substitute into the ARG_TYPES of a function type.
12542 If END is a TREE_CHAIN, leave it and any following types
12543 un-substituted. */
12545 static tree
12547 tree args,
12548 tree end,
12549 tsubst_flags_t complain,
12550 tree in_decl)
12551 {
12552 tree remaining_arg_types;
12556 tree default_arg;
12567 {
12568 /* For a pack expansion, perform substitution on the
12569 entire expression. Later on, we'll handle the arguments
12570 one-by-one. */
12575 /* So that we'll spin through the parameters, one by one. */
12577 else
12578 {
12579 /* We only partially substituted into the parameter
12580 pack. Our type is TYPE_PACK_EXPANSION. */
12583 }
12584 }
12597 {
12599 {
12603 }
12605 }
12606 /* DR 657. */
12610 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12611 top-level qualifiers as required. */
12614 /* We do not substitute into default arguments here. The standard
12615 mandates that they be instantiated only when needed, which is
12616 done in build_over_call. */
12620 {
12621 /* We've instantiated a template before its default arguments
12622 have been parsed. This can happen for a nested template
12623 class, and is not an error unless we require the default
12624 argument in a call of this function. */
12625 remaining_arg_types =
12628 }
12629 else
12630 remaining_arg_types =
12632 }
12635 }
12637 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12638 *not* handle the exception-specification for FNTYPE, because the
12639 initial substitution of explicitly provided template parameters
12640 during argument deduction forbids substitution into the
12641 exception-specification:
12643 [temp.deduct]
12645 All references in the function type of the function template to the
12646 corresponding template parameters are replaced by the specified tem-
12647 plate argument values. If a substitution in a template parameter or
12648 in the function type of the function template results in an invalid
12649 type, type deduction fails. [Note: The equivalent substitution in
12650 exception specifications is done only when the function is instanti-
12651 ated, at which point a program is ill-formed if the substitution
12652 results in an invalid type.] */
12654 static tree
12656 tree args,
12657 tsubst_flags_t complain,
12658 tree in_decl)
12659 {
12660 tree return_type;
12662 tree fntype;
12664 /* The TYPE_CONTEXT is not used for function/method types. */
12667 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12668 failure. */
12672 {
12673 /* Substitute the argument types. */
12685 {
12686 /* DR 1207: 'this' is in scope in the trailing return type. */
12688 }
12690 /* Substitute the return type. */
12694 {
12697 }
12698 }
12699 else
12700 /* Substitute the return type. */
12705 /* DR 486 clarifies that creation of a function type with an
12706 invalid return type is a deduction failure. */
12709 {
12711 {
12714 else
12716 }
12718 }
12719 /* And DR 657. */
12724 {
12725 /* Substitute the argument types. */
12730 }
12732 /* Construct a new type node and return it. */
12734 {
12739 }
12740 else
12741 {
12743 /* Don't pick up extra function qualifiers from the basetype. */
12746 {
12747 /* [temp.deduct]
12749 Type deduction may fail for any of the following
12750 reasons:
12752 -- Attempting to create "pointer to member of T" when T
12753 is not a class type. */
12756 r);
12758 }
12763 }
12770 }
12772 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12773 ARGS into that specification, and return the substituted
12774 specification. If there is no specification, return NULL_TREE. */
12776 static tree
12778 tree args,
12779 tsubst_flags_t complain,
12780 tree in_decl,
12782 {
12783 tree specs;
12784 tree new_specs;
12789 {
12790 /* A noexcept-specifier. */
12795 {
12796 /* Defer instantiation of noexcept-specifiers to avoid
12797 excessive instantiations (c++/49107). */
12800 {
12801 /* We already partially instantiated this member template,
12802 so combine the new args with the old. */
12807 }
12808 else
12809 {
12812 }
12813 }
12814 else
12815 new_specs = tsubst_copy_and_build
12819 }
12821 {
12824 else
12826 {
12827 tree spec;
12832 {
12833 /* Expand the pack expansion type. */
12836 in_decl);
12842 else
12843 {
12844 /* We're substituting into a member template, so
12845 we got a TYPE_PACK_EXPANSION back. Add that
12846 expansion and move on. */
12850 expanded_specs,
12851 complain);
12854 }
12855 }
12858 {
12861 else
12866 complain);
12867 }
12870 }
12871 }
12873 }
12875 /* Take the tree structure T and replace template parameters used
12876 therein with the argument vector ARGS. IN_DECL is an associated
12877 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12878 Issue error and warning messages under control of COMPLAIN. Note
12879 that we must be relatively non-tolerant of extensions here, in
12880 order to preserve conformance; if we allow substitutions that
12881 should not be allowed, we may allow argument deductions that should
12882 not succeed, and therefore report ambiguous overload situations
12883 where there are none. In theory, we could allow the substitution,
12884 but indicate that it should have failed, and allow our caller to
12885 make sure that the right thing happens, but we don't try to do this
12886 yet.
12888 This function is used for dealing with types, decls and the like;
12889 for expressions, use tsubst_expr or tsubst_copy. */
12891 tree
12893 {
12916 else
12921 /* Reuse typedefs. We need to do this to handle dependent attributes,
12922 such as attribute aligned. */
12925 {
12929 {
12930 /* DECL represents an alias template and we want to
12931 instantiate it. */
12935 }
12939 {
12943 }
12948 else
12949 /* The typedef is from a non-template context. */
12953 {
12955 r = cp_build_qualified_type_real
12959 }
12960 else
12961 {
12962 /* We don't have an instantiation yet, so drop the typedef. */
12967 }
12968 }
12981 {
13007 {
13013 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13014 needed. */
13020 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13021 with TREE_SIDE_EFFECTS that indicates this is not an integral
13022 constant expression. */
13025 {
13028 }
13031 }
13037 {
13043 /* Early in template argument deduction substitution, we don't
13044 want to reduce the level of 'auto', or it will be confused
13045 with a normal template parm in subsequent deduction. */
13057 {
13061 {
13062 /* See through ARGUMENT_PACK_SELECT arguments. */
13064 /* If the selected argument is an expansion E, that most
13065 likely means we were called from
13066 gen_elem_of_pack_expansion_instantiation during the
13067 substituting of pack an argument pack (which Ith
13068 element is a pack expansion, where I is
13069 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13070 In this case, the Ith element resulting from this
13071 substituting is going to be a pack expansion, which
13072 pattern is the pattern of E. Let's return the
13073 pattern of E, and
13074 gen_elem_of_pack_expansion_instantiation will
13075 build the resulting pack expansion from it. */
13077 {
13078 /* Make sure we aren't throwing away arg info. */
13081 }
13082 }
13083 }
13088 {
13090 /* If ARG is an argument pack, we don't actually want to
13091 perform a substitution here, because substitutions
13092 for argument packs are only done
13093 element-by-element. We can get to this point when
13094 substituting the type of a non-type template
13095 parameter pack, when that type actually contains
13096 template parameter packs from an outer template, e.g.,
13098 template<typename... Types> struct A {
13099 template<Types... Values> struct B { };
13100 }; */
13104 {
13110 return cp_build_qualified_type_real
13112 }
13114 {
13115 /* We are processing a type constructed from a
13116 template template parameter. */
13127 /* Consider this code:
13129 template <template <class> class Template>
13130 struct Internal {
13131 template <class Arg> using Bind = Template<Arg>;
13132 };
13134 template <template <class> class Template, class Arg>
13135 using Instantiate = Template<Arg>; //#0
13137 template <template <class> class Template,
13138 class Argument>
13139 using Bind =
13140 Instantiate<Internal<Template>::template Bind,
13141 Argument>; //#1
13143 When #1 is parsed, the
13144 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13145 parameter `Template' in #0 matches the
13146 UNBOUND_CLASS_TEMPLATE representing the argument
13147 `Internal<Template>::template Bind'; We then want
13148 to assemble the type `Bind<Argument>' that can't
13149 be fully created right now, because
13150 `Internal<Template>' not being complete, the Bind
13151 template cannot be looked up in that context. So
13152 we need to "store" `Bind<Argument>' for later
13153 when the context of Bind becomes complete. Let's
13154 store that in a TYPENAME_TYPE. */
13158 argvec),
13159 typename_type,
13160 complain);
13162 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13163 are resolving nested-types in the signature of a
13164 member function templates. Otherwise ARG is a
13165 TEMPLATE_DECL and is the real template to be
13166 instantiated. */
13174 complain);
13175 return cp_build_qualified_type_real
13177 }
13178 else
13179 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
13181 }
13184 /* This can happen during the attempted tsubst'ing in
13185 unify. This means that we don't yet have any information
13186 about the template parameter in question. */
13189 /* If we get here, we must have been looking at a parm for a
13190 more deeply nested template. Make a new version of this
13191 template parameter, but with a lower level. */
13193 {
13198 {
13200 r = cp_build_qualified_type_real
13204 }
13211 /* Break infinite recursion when substituting the constraints
13213 else
13214 {
13224 /* Propagate constraints on placeholders. */
13231 /* We have reduced the level of the template
13232 template parameter, but not the levels of its
13233 template parameters, so canonical_type_parameter
13234 will not be able to find the canonical template
13235 template parameter for this level. Thus, we
13236 require structural equality checking to compare
13237 TEMPLATE_TEMPLATE_PARMs. */
13241 else
13245 {
13247 /* We might need to substitute into the types of non-type
13248 template parameters. */
13260 }
13261 }
13270 }
13273 }
13276 {
13284 {
13288 }
13291 {
13295 }
13298 {
13302 }
13308 }
13311 /* We should never be tsubsting a binfo. */
13315 /* A vector of template arguments. */
13321 {
13325 /* [temp.deduct]
13327 Type deduction may fail for any of the following
13328 reasons:
13330 -- Attempting to create a pointer to reference type.
13331 -- Attempting to create a reference to a reference type or
13332 a reference to void.
13334 Core issue 106 says that creating a reference to a reference
13335 during instantiation is no longer a cause for failure. We
13336 only enforce this check in strict C++98 mode. */
13340 {
13343 /* We keep track of the last time we issued this error
13344 message to avoid spewing a ton of messages during a
13345 single bad template instantiation. */
13348 {
13353 else
13356 }
13359 }
13363 {
13365 {
13368 type);
13369 else
13371 type);
13372 }
13374 }
13376 {
13380 }
13382 /* In C++0x, during template argument substitution, when there is an
13383 attempt to create a reference to a reference type, reference
13384 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13386 "If a template-argument for a template-parameter T names a type
13387 that is a reference to a type A, an attempt to create the type
13388 'lvalue reference to cv T' creates the type 'lvalue reference to
13389 A,' while an attempt to create the type type rvalue reference to
13390 cv T' creates the type T"
13391 */
13392 r = cp_build_reference_type
13395 else
13400 /* Will this ever be needed for TYPE_..._TO values? */
13404 }
13406 {
13409 {
13410 /* [temp.deduct]
13412 Type deduction may fail for any of the following
13413 reasons:
13415 -- Attempting to create "pointer to member of T" when T
13416 is not a class type. */
13420 }
13422 {
13426 }
13428 {
13432 }
13435 {
13436 /* The type of the implicit object parameter gets its
13437 cv-qualifiers from the FUNCTION_TYPE. */
13438 tree memptr;
13439 tree method_type
13444 complain);
13445 }
13446 else
13449 complain);
13450 }
13453 {
13454 tree fntype;
13455 tree specs;
13460 /* Substitute the exception specification. */
13468 }
13470 {
13475 /* As an optimization, we avoid regenerating the array type if
13476 it will obviously be the same as T. */
13480 /* These checks should match the ones in create_array_type_for_decl.
13482 [temp.deduct]
13484 The deduction may fail for any of the following reasons:
13486 -- Attempting to create an array with an element type that
13487 is void, a function type, or a reference type, or [DR337]
13488 an abstract class type. */
13494 {
13498 }
13506 {
13509 }
13512 }
13515 {
13527 {
13531 }
13533 {
13534 /* Normally, make_typename_type does not require that the CTX
13535 have complete type in order to allow things like:
13537 template <class T> struct S { typename S<T>::X Y; };
13539 But, such constructs have already been resolved by this
13540 point, so here CTX really should have complete type, unless
13541 it's a partial instantiation. */
13544 {
13548 }
13549 }
13556 {
13559 }
13562 {
13564 {
13568 else
13570 }
13572 {
13576 else
13578 }
13579 }
13581 return cp_build_qualified_type_real
13583 }
13586 {
13598 }
13601 {
13602 tree type;
13618 complain);
13619 }
13622 {
13623 tree type;
13634 {
13636 {
13640 }
13643 }
13653 else
13654 {
13658 /* In a template ~id could be either a complement expression
13659 or an unqualified-id naming a destructor; if instantiating
13660 it produces an expression, it's not an id-expression or
13661 member access. */
13664 }
13669 }
13672 {
13676 }
13680 {
13682 tree packed_out =
13684 args,
13685 complain,
13686 in_decl);
13689 /* For template nontype argument packs, also substitute into
13690 the type. */
13695 }
13711 /* We should use one of the expression tsubsts for these codes. */
13717 }
13718 }
13720 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13721 type of the expression on the left-hand side of the "." or "->"
13722 operator. */
13724 static tree
13727 {
13728 tree name;
13729 tree qualifying_scope;
13730 tree fns;
13731 tree optype;
13736 /* A baselink indicates a function from a base class. Both the
13737 BASELINK_ACCESS_BINFO and the base class referenced may
13738 indicate bases of the template class, rather than the
13739 instantiated class. In addition, lookups that were not
13740 ambiguous before may be ambiguous now. Therefore, we perform
13741 the lookup again. */
13748 {
13755 }
13761 {
13763 {
13767 }
13769 }
13771 /* If lookup found a single function, mark it as used at this
13772 point. (If it lookup found multiple functions the one selected
13773 later by overload resolution will be marked as used at that
13774 point.) */
13781 /* Add back the template arguments, if present. */
13785 unknown_type_node,
13787 template_args);
13788 /* Update the conversion operator type. */
13796 {
13798 qualifying_scope,
13799 object_type);
13801 /* We need to call adjust_result_of_qualified_name_lookup in case the
13802 destructor names a base class, but we unset BASELINK_QUALIFIED_P
13803 so that we still get virtual function binding. */
13805 }
13807 }
13809 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13810 true if the qualified-id will be a postfix-expression in-and-of
13811 itself; false if more of the postfix-expression follows the
13812 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13813 of "&". */
13815 static tree
13819 {
13820 tree expr;
13821 tree scope;
13822 tree name;
13824 tree template_args;
13829 /* Figure out what name to look up. */
13832 {
13842 }
13843 else
13844 {
13847 }
13849 /* Substitute into the qualifying scope. When there are no ARGS, we
13850 are just trying to simplify a non-dependent expression. In that
13851 case the qualifying scope may be dependent, and, in any case,
13852 substituting will not help. */
13855 {
13858 }
13859 else
13863 {
13870 }
13873 {
13875 {
13876 /* A BIT_NOT_EXPR is used to represent a destructor. */
13878 {
13882 }
13883 else
13886 }
13887 else
13891 {
13893 {
13897 }
13899 }
13900 }
13903 {
13905 scope);
13906 /* Remember that there was a reference to this entity. */
13909 }
13912 {
13918 }
13921 {
13924 complain);
13925 else
13927 }
13933 {
13934 expr = (adjust_result_of_qualified_name_lookup
13936 expr = (finish_qualified_id_expr
13940 }
13942 /* Expressions do not generally have reference type. */
13944 /* However, if we're about to form a pointer-to-member, we just
13945 want the referenced member referenced. */
13953 }
13955 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
13956 initializer, DECL is the substituted VAR_DECL. Other arguments are as
13957 for tsubst. */
13959 static tree
13962 {
13969 {
13970 /* If we had an initializer but it
13971 instantiated to nothing,
13972 value-initialize the object. This will
13973 only occur when the initializer was a
13974 pack expansion where the parameter packs
13975 used in that expansion were of length
13976 zero. */
13978 complain);
13981 }
13984 }
13986 /* Like tsubst, but deals with expressions. This function just replaces
13987 template parms; to finish processing the resultant expression, use
13988 tsubst_copy_and_build or tsubst_expr. */
13990 static tree
13992 {
13994 tree r;
14002 {
14007 {
14008 /* We get here for a use of 'this' in an NSDMI as part of a
14009 constructor call or as part of an aggregate initialization. */
14011 && ((current_function_decl
14013 || (current_class_ref
14017 /* This can happen for a parameter name used later in a function
14018 declaration (such as in a late-specified return type). Just
14019 make a dummy decl, since it's only used for its type. */
14022 /* Give it the template pattern as its context; its true context
14023 hasn't been instantiated yet and this is good enough for
14024 mangling. */
14026 }
14035 {
14036 tree enum_type;
14037 tree v;
14041 /* There is no need to substitute into namespace-scope
14042 enumerators. */
14045 /* If ARGS is NULL, then T is known to be non-dependent. */
14049 /* Unfortunately, we cannot just call lookup_name here.
14050 Consider:
14052 template <int I> int f() {
14053 enum E { a = I };
14054 struct S { void g() { E e = a; } };
14055 };
14057 When we instantiate f<7>::S::g(), say, lookup_name is not
14058 clever enough to find f<7>::a. */
14059 enum_type
14069 /* We didn't find the name. That should never happen; if
14070 name-lookup found it during preliminary parsing, we
14071 should find it again here during instantiation. */
14073 }
14078 {
14079 /* Check for a local specialization set up by
14080 tsubst_pack_expansion. */
14082 {
14086 }
14088 /* When retrieving a capture pack from a generic lambda, remove the
14089 lambda call op's own template argument list from ARGS. Only the
14090 template arguments active for the closure type should be used to
14091 retrieve the pack specialization. */
14097 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14098 tsubst_decl put in the hash table. */
14100 }
14103 {
14104 tree ctx;
14109 {
14112 {
14116 }
14118 }
14119 }
14129 {
14132 {
14133 /* First try name lookup to find the instantiation. */
14136 {
14137 /* Make sure that the one we found is the one we want. */
14143 }
14147 else
14148 {
14149 /* This can happen for a variable used in a
14150 late-specified return type of a local lambda, or for a
14151 local static or constant. Building a new VAR_DECL
14152 should be OK in all those cases. */
14155 {
14156 /* We can't call cp_finish_decl, so handle the
14157 initializer by hand. */
14168 }
14175 }
14176 /* Remember this for subsequent uses. */
14179 }
14180 }
14181 else
14191 /* An OVERLOAD will always be a non-dependent overload set; an
14192 overload set from function scope will just be represented with an
14193 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14209 {
14210 /* Template template argument like the following example need
14211 special treatment:
14213 template <template <class> class TT> struct C {};
14214 template <class T> struct D {
14215 template <class U> struct E {};
14216 C<E> c; // #1
14217 };
14218 D<int> d; // #2
14220 We are processing the template argument `E' in #1 for
14221 the template instantiation #2. Originally, `E' is a
14222 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14223 have to substitute this with one having context `D<int>'. */
14227 }
14228 else
14229 /* Ordinary template template argument. */
14240 {
14244 }
14249 {
14258 /* We only want to compute the number of arguments. */
14261 else
14268 {
14270 /* Set TREE_USED for the benefit of -Wunused. */
14274 }
14282 {
14287 else
14293 else
14296 }
14297 else
14299 }
14301 {
14309 }
14310 /* Fall through */
14326 {
14330 }
14333 {
14334 tree object;
14335 tree name;
14340 {
14344 }
14347 {
14357 }
14362 in_decl);
14363 else
14366 }
14404 {
14408 }
14411 {
14416 }
14419 {
14423 }
14426 {
14434 }
14440 {
14447 }
14450 {
14457 }
14460 {
14467 }
14470 {
14471 /* Substituted template arguments */
14480 }
14483 {
14503 }
14528 /* Fall through. */
14531 {
14534 }
14535 else
14539 /* This is handled by tsubst_copy_and_build. */
14543 {
14547 }
14550 /* We shouldn't have built any of these during initial template
14551 generation. Instead, they should be built during instantiation
14552 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14556 {
14566 }
14584 {
14585 /* Instantiate any typedefs in the type. */
14590 }
14593 /* These can sometimes show up in a partial instantiation, but never
14594 involve template parms. */
14608 /* We shouldn't get here, but keep going if !flag_checking. */
14612 }
14613 }
14615 /* Helper function for tsubst_omp_clauses, used for instantiation of
14616 OMP_CLAUSE_DECL of clauses. */
14618 static tree
14620 tree in_decl)
14621 {
14625 /* Handle an OpenMP array section represented as a TREE_LIST (or
14626 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
14627 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
14628 TREE_LIST. We can handle it exactly the same as an array section
14629 (purpose, value, and a chain), even though the nomenclature
14630 (low_bound, length, etc) is different. */
14632 {
14633 tree low_bound
14639 in_decl);
14648 }
14651 /* Undo convert_from_reference tsubst_expr could have called. */
14657 }
14659 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14661 static tree
14664 {
14669 {
14675 {
14678 {
14684 }
14685 /* FALLTHRU */
14700 in_decl);
14731 {
14734 {
14741 }
14742 else
14744 }
14747 in_decl);
14753 in_decl);
14761 in_decl);
14763 {
14766 }
14771 else
14774 in_decl,
14797 {
14801 loc;
14803 {
14806 }
14807 }
14811 }
14814 {
14824 /* tsubst_expr on SCOPE_REF results in returning
14825 finish_non_static_data_member result. Undo that here. */
14829 {
14834 {
14838 CASE_CONVERT:
14847 /* FALLTHRU */
14851 }
14852 }
14858 {
14861 {
14865 }
14866 }
14870 }
14871 }
14875 {
14880 {
14883 }
14884 }
14886 }
14888 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
14890 static tree
14892 tree in_decl)
14893 {
14894 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
14914 {
14917 else
14918 {
14922 }
14923 }
14928 #undef RECUR
14929 }
14931 /* Used to temporarily communicate the list of #pragma omp parallel
14932 clauses to #pragma omp for instantiation if they are combined
14933 together. */
14937 /* Substitute one OMP_FOR iterator. */
14939 static void
14944 {
14945 #define RECUR(NODE) \
14946 tsubst_expr ((NODE), args, complain, in_decl, \
14947 integral_constant_expression_p)
14954 {
14957 }
14963 {
14964 /* We need to jump through some hoops to handle declarations in the
14965 for-init-statement, since we might need to handle auto deduction,
14966 but we need to keep control of initialization. */
14970 }
14971 else
14972 {
14974 {
14977 {
14981 {
14985 CASE_CONVERT:
14993 {
14996 }
14997 /* FALLTHRU */
15001 }
15002 }
15003 }
15004 else
15006 }
15017 {
15019 {
15020 /* Declare the variable, but don't let that initialize it. */
15025 }
15030 {
15035 }
15036 else
15043 }
15046 {
15047 /* Declare and initialize the variable. */
15050 }
15052 {
15056 {
15058 {
15064 {
15067 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15072 }
15075 {
15077 decl);
15079 }
15082 {
15084 decl);
15086 }
15087 else
15089 }
15092 }
15094 {
15099 {
15102 }
15103 }
15104 }
15107 {
15111 }
15112 else
15116 {
15127 {
15135 }
15136 else
15142 {
15148 }
15152 {
15160 }
15161 else
15167 }
15173 #undef RECUR
15174 }
15176 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15177 of OMP_TARGET's body. */
15179 static tree
15181 {
15184 {
15193 }
15195 }
15197 /* Like tsubst_copy for expressions, etc. but also does semantic
15198 processing. */
15200 tree
15203 {
15204 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15205 #define RECUR(NODE) \
15206 tsubst_expr ((NODE), args, complain, in_decl, \
15207 integral_constant_expression_p)
15210 tree r;
15211 location_t loc;
15223 {
15225 {
15226 tree_stmt_iterator i;
15230 }
15245 else
15254 {
15256 tree init;
15262 {
15272 else
15274 }
15276 {
15277 /* Don't build up decls for a variadic capture proxy, we'll
15278 instantiate the elements directly as needed. */
15280 }
15281 else
15282 {
15286 {
15287 /* By marking the declaration as instantiated, we avoid
15288 trying to instantiate it. Since instantiate_decl can't
15289 handle local variables, and since we've already done
15290 all that needs to be done, that's the right thing to
15291 do. */
15296 /* Anonymous aggregates are a special case. */
15299 {
15302 {
15306 }
15308 }
15314 {
15319 }
15320 else
15321 {
15326 {
15327 /* For __PRETTY_FUNCTION__ we have to adjust the
15328 initializer. */
15332 }
15333 else
15337 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15340 }
15341 }
15342 }
15345 }
15360 {
15370 }
15396 else
15403 {
15407 }
15415 else
15423 else
15444 {
15448 }
15452 {
15454 tree label;
15459 }
15465 /* Computed goto's must be tsubst'd into. On the other hand,
15466 non-computed gotos must not be; the identifier in question
15467 will have no binding. */
15469 else
15475 {
15491 }
15496 {
15501 }
15502 else
15503 {
15508 else
15515 else
15521 else
15523 }
15527 {
15531 {
15533 /* Prevent instantiate_decl from trying to instantiate
15534 this variable. We've already done all that needs to be
15535 done. */
15538 }
15543 }
15549 {
15550 /* Local classes are not independent templates; they are
15551 instantiated along with their containing function. And this
15552 way we don't have to deal with pushing out of one local class
15553 to instantiate a member of another local class. */
15554 tree fn;
15555 /* Closures are handled by the LAMBDA_EXPR. */
15561 }
15565 {
15566 tree condition;
15569 condition =
15571 args,
15580 }
15586 in_decl);
15623 {
15638 in_decl);
15640 {
15647 }
15659 integral_constant_expression_p);
15670 else
15671 {
15679 }
15683 }
15688 /* FALLTHRU */
15695 in_decl);
15712 in_decl);
15723 {
15726 {
15727 /* For combined target teams, ensure the num_teams and
15728 thread_limit clause expressions are evaluated on the host,
15729 before entering the target construct. */
15730 tree c;
15736 {
15745 OMP_CLAUSE_FIRSTPRIVATE);
15749 }
15750 }
15751 }
15811 {
15816 {
15819 }
15825 }
15826 else
15827 {
15834 {
15837 }
15840 {
15845 {
15848 }
15854 }
15855 else
15856 {
15860 }
15863 }
15867 {
15873 {
15877 {
15882 }
15886 }
15887 else
15888 {
15893 }
15894 }
15898 {
15902 }
15922 /* If the first operand was a statement, we're done with it. */
15926 complain));
15938 integral_constant_expression_p));
15939 }
15942 out:
15945 #undef RECUR
15946 #undef RETURN
15947 }
15949 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
15950 function. For description of the body see comment above
15951 cp_parser_omp_declare_reduction_exprs. */
15953 static void
15955 {
15961 tree_stmt_iterator tsi;
15972 {
15991 }
15993 {
16013 }
16014 }
16016 /* T is a postfix-expression that is not being used in a function
16017 call. Return the substituted version of T. */
16019 static tree
16021 tsubst_flags_t complain,
16022 tree in_decl)
16023 {
16027 else
16033 }
16035 /* Like tsubst but deals with expressions and performs semantic
16036 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16038 tree
16040 tree args,
16041 tsubst_flags_t complain,
16042 tree in_decl,
16045 {
16046 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16047 #define RECUR(NODE) \
16048 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16050 integral_constant_expression_p)
16053 location_t loc;
16062 /* N3276 decltype magic only applies to calls at the top level or on the
16063 right side of a comma. */
16068 {
16071 /* Fall through. */
16073 {
16074 tree decl;
16075 cp_id_kind idk;
16080 {
16083 }
16085 /* Look up the name. */
16088 /* By convention, expressions use ERROR_MARK_NODE to indicate
16089 failure, not NULL_TREE. */
16095 integral_constant_expression_p,
16103 input_location);
16107 {
16111 }
16113 }
16116 {
16117 tree object;
16130 {
16133 }
16134 else
16141 else
16143 }
16146 {
16150 {
16151 /* A type conversion to reference type will be enclosed in
16152 such an indirect ref, but the substitution of the cast
16153 will have also added such an indirect ref. */
16156 }
16157 else
16165 }
16168 {
16172 }
16175 {
16182 flags));
16183 }
16186 {
16190 }
16197 {
16198 tree type;
16204 {
16209 }
16215 {
16233 }
16236 }
16270 else
16272 in_decl);
16307 {
16314 tree r = build_x_binary_op
16316 op0,
16318 ? ERROR_MARK
16320 op1,
16322 ? ERROR_MARK
16330 }
16333 {
16337 }
16350 {
16359 }
16364 /* Fall through */
16367 {
16368 tree r;
16374 {
16375 /* When there are no ARGS, we are trying to evaluate a
16376 non-dependent expression from the parser. Trying to do
16377 the substitutions may not work. */
16380 }
16381 else
16382 {
16387 else
16390 /*integral_constant_expression_p=*/
16394 }
16398 else
16402 {
16404 {
16406 {
16410 }
16411 else
16415 }
16417 }
16419 }
16422 {
16432 }
16448 {
16452 tree r = build_x_modify_expr
16455 /* TREE_NO_WARNING must be set if either the expression was
16456 parenthesized or it uses an operator such as >>= rather
16457 than plain assignment. In the former case, it was already
16458 set and must be copied. In the latter case,
16459 build_x_modify_expr sets it and it must not be reset
16460 here. */
16465 }
16470 /* Remember that there was a reference to this entity. */
16477 {
16482 tree ret;
16486 else
16487 {
16491 }
16493 /* If there was an initializer in the original tree, but it
16494 instantiated to an empty list, then we should pass a
16495 non-NULL empty vector to tell build_new that it was an
16496 empty initializer() rather than no initializer. This can
16497 only happen when the initializer is a pack expansion whose
16498 parameter packs are of length zero. */
16501 else
16502 {
16506 else
16507 {
16510 }
16511 }
16517 complain);
16525 }
16528 {
16534 complain));
16535 }
16538 {
16542 integral_constant_expression_p);
16544 op0,
16547 }
16550 {
16551 tree function;
16556 tree ret;
16559 /* When we parsed the expression, we determined whether or
16560 not Koenig lookup should be performed. */
16563 {
16568 }
16570 {
16571 /* Do nothing; calling tsubst_copy_and_build on an identifier
16572 would incorrectly perform unqualified lookup again.
16574 Note that we can also have an IDENTIFIER_NODE if the earlier
16575 unqualified lookup found a member function; in that case
16576 koenig_p will be false and we do want to do the lookup
16577 again to find the instantiated member function.
16579 FIXME but doing that causes c++/15272, so we need to stop
16580 using IDENTIFIER_NODE in that situation. */
16582 }
16583 else
16584 {
16586 {
16592 }
16593 else
16598 /* Avoid error about taking the address of a constructor. */
16602 in_decl,
16604 integral_constant_expression_p);
16608 }
16613 {
16618 else
16619 {
16620 /* Expand the pack expansion and push each entry onto
16621 CALL_ARGS. */
16624 {
16629 {
16634 }
16635 }
16636 else
16637 {
16638 /* A partial substitution. Add one entry. */
16640 }
16641 }
16642 }
16644 /* We do not perform argument-dependent lookup if normal
16645 lookup finds a non-function, in accordance with the
16646 expected resolution of DR 218. */
16649 /* If lookup found a member function, the Koenig lookup is
16650 not appropriate, even if an unqualified-name was used
16651 to denote the function. */
16654 /* Only do this when substitution turns a dependent call
16655 into a non-dependent call. */
16662 {
16664 {
16665 /* For backwards compatibility and good diagnostics, try
16666 the unqualified lookup again if we aren't in SFINAE
16667 context. */
16668 tree unq = (tsubst_copy_and_build
16670 integral_constant_expression_p));
16675 {
16684 "%qD was not declared in this scope, "
16685 "and no declarations were found by "
16686 "argument-dependent lookup at the point "
16688 {
16692 {
16694 input_location);
16696 "declarations in dependent base %qT are "
16702 else
16706 }
16707 else
16709 "%qD declared here, later in the "
16711 }
16713 }
16714 }
16716 {
16721 }
16722 }
16724 /* Remember that there was a reference to this entity. */
16729 /* Put back tf_decltype for the actual call. */
16734 complain);
16736 {
16751 complain);
16752 else
16753 ret = (build_new_method_call
16758 complain));
16759 }
16760 else
16763 koenig_p,
16764 complain);
16769 {
16775 {
16781 {
16783 /* The thunk location is not interesting. */
16785 }
16786 }
16787 }
16790 }
16793 {
16799 {
16801 {
16806 }
16807 else
16808 {
16813 }
16815 }
16816 else
16817 {
16820 }
16824 }
16827 {
16832 input_location));
16833 }
16836 {
16844 {
16845 /* We have pack expansions, so expand those and
16846 create a new list out of it. */
16849 tree chain;
16852 /* Expand the argument expressions. */
16860 /* Build the rest of the list. */
16865 /* Determine the number of arguments. */
16867 {
16870 }
16873 else
16874 {
16875 /* Since we only performed a partial substitution into
16876 the argument pack, we only RETURN (a single list
16877 node. */
16884 }
16886 /* Convert the argument vectors into a TREE_LIST */
16889 {
16890 /* Grab the Ith values. */
16891 i--;
16894 value
16898 /* Build the list (backwards). */
16900 }
16903 }
16919 }
16922 {
16923 tree object;
16924 tree object_type;
16925 tree member;
16926 tree r;
16930 /* Remember that there was a reference to this entity. */
16941 else
16949 {
16951 {
16956 {
16959 }
16961 {
16966 }
16967 }
16968 }
16971 {
16972 /* Lookup the template functions now that we know what the
16973 scope is. */
16981 {
16984 args);
16985 member = (adjust_result_of_qualified_name_lookup
16987 object_type));
16988 }
16989 else
16990 {
16992 input_location);
16994 }
16995 }
16999 {
17001 {
17005 else
17008 }
17010 }
17012 {
17017 }
17021 complain);
17025 }
17032 {
17040 tree r;
17045 /* digest_init will do the wrong thing if we let it. */
17049 /* We do not want to process the index of aggregate
17050 initializers as they are identifier nodes which will be
17051 looked up by digest_init. */
17057 {
17059 /* An identifier index is looked up in the type
17060 being initialized, not the current scope. */
17065 {
17066 /* Substitute into the pack expansion. */
17068 in_decl);
17072 ;
17074 /* Just move the argument into place. */
17076 else
17077 {
17078 /* Update the length of the final CONSTRUCTOR
17079 arguments vector, and note that we will need to
17080 copy.*/
17083 }
17084 }
17085 else
17087 }
17090 {
17095 {
17097 {
17102 }
17103 else
17105 }
17106 }
17116 }
17119 {
17122 {
17125 }
17126 else
17127 {
17130 }
17131 }
17137 {
17138 /* We don't build decls for an instantiation of a
17139 variadic capture proxy, we instantiate the elements
17140 when needed. */
17143 }
17144 /* Fall through */
17147 {
17149 /* ??? We're doing a subset of finish_id_expression here. */
17151 && !processing_template_decl
17152 && !cp_unevaluated_operand
17155 {
17157 /* Replace an evaluated use of the thread_local variable with
17158 a call to its wrapper. */
17160 }
17162 {
17166 }
17169 /* If the original type was a reference, we'll be wrapped in
17170 the appropriate INDIRECT_REF. */
17173 }
17176 {
17180 }
17187 {
17198 }
17201 {
17207 integral_constant_expression_p);
17211 /* If the resulting list of expression statement is empty,
17212 fold it further into void_node. */
17217 }
17220 {
17238 /* For a function or variable scope, we want to use tsubst so that we
17239 don't complain about referring to an auto before deduction. */
17242 {
17243 /* Look up the parameter we want directly, as tsubst_copy
17244 doesn't do what we need. */
17250 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17253 }
17255 /* For a field, use tsubst_copy so that we look up the existing field
17256 rather than build a new one. */
17258 else
17265 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17267 /* Now that we know visibility, instantiate the type so we have a
17268 declaration of the op() for later calls to lambda_function. */
17279 }
17282 /* We can get here for a constant initializer of non-dependent type.
17283 FIXME stop folding in cp_parser_initializer_clause. */
17284 {
17286 complain);
17288 }
17292 integral_constant_expression_p));
17298 {
17303 complain));
17304 }
17310 /* Handle Objective-C++ constructs, if appropriate. */
17311 {
17312 tree subst
17317 }
17319 }
17321 #undef RECUR
17322 #undef RETURN
17323 out:
17326 }
17328 /* Verify that the instantiated ARGS are valid. For type arguments,
17329 make sure that the type's linkage is ok. For non-type arguments,
17330 make sure they are constants if they are integral or enumerations.
17331 Emit an error under control of COMPLAIN, and return TRUE on error. */
17333 static bool
17335 {
17339 {
17349 }
17351 {
17352 /* [basic.link]: A name with no linkage (notably, the name
17353 of a class or enumeration declared in a local scope)
17354 shall not be used to declare an entity with linkage.
17355 This implies that names with no linkage cannot be used as
17356 template arguments
17358 DR 757 relaxes this restriction for C++0x. */
17363 {
17364 /* DR 488 makes use of a type with no linkage cause
17365 type deduction to fail. */
17367 {
17370 else
17373 }
17375 }
17376 /* In order to avoid all sorts of complications, we do not
17377 allow variably-modified types as template arguments. */
17379 {
17383 }
17384 }
17385 /* Class template and alias template arguments should be OK. */
17387 ;
17388 /* A non-type argument of integral or enumerated type must be a
17389 constant. */
17394 {
17398 }
17400 }
17402 static bool
17404 {
17409 {
17412 }
17416 }
17418 /* We're out of SFINAE context now, so generate diagnostics for the access
17419 errors we saw earlier when instantiating D from TMPL and ARGS. */
17421 static void
17423 {
17435 }
17437 /* Instantiate the indicated variable, function, or alias template TMPL with
17438 the template arguments in TARG_PTR. */
17440 static tree
17442 {
17444 tree fndecl;
17445 tree gen_tmpl;
17446 tree spec;
17454 /* If this function is a clone, handle it specially. */
17456 {
17457 tree spec;
17458 tree clone;
17460 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
17461 DECL_CLONED_FUNCTION. */
17467 /* Look for the clone. */
17471 /* We should always have found the clone by now. */
17474 }
17479 /* Check to see if we already have this specialization. */
17483 /* targ_ptr only has the innermost template args, so add the outer ones
17484 from tmpl, which could be either a partial instantiation or gen_tmpl (in
17485 the case of a non-dependent call within a template definition). */
17486 targ_ptr = (add_outermost_template_args
17488 targ_ptr));
17490 /* It would be nice to avoid hashing here and then again in tsubst_decl,
17491 but it doesn't seem to be on the hot path. */
17500 {
17502 {
17506 }
17508 }
17511 complain))
17514 /* We are building a FUNCTION_DECL, during which the access of its
17515 parameters and return types have to be checked. However this
17516 FUNCTION_DECL which is the desired context for access checking
17517 is not built yet. We solve this chicken-and-egg problem by
17518 deferring all checks until we have the FUNCTION_DECL. */
17521 /* Instantiation of the function happens in the context of the function
17522 template, not the context of the overload resolution we're doing. */
17524 /* If there are dependent arguments, e.g. because we're doing partial
17525 ordering, make sure processing_template_decl stays set. */
17529 {
17533 }
17539 {
17540 /* We need to determine if we're using a partial or explicit
17541 specialization now, because the type of the variable could be
17542 different. */
17548 {
17553 }
17554 }
17556 /* Substitute template parameters to obtain the specialization. */
17564 {
17567 }
17569 /* The DECL_TI_TEMPLATE should always be the immediate parent
17570 template, not the most general template. */
17574 /* Now we know the specialization, compute access previously
17575 deferred. */
17582 /* If we've just instantiated the main entry point for a function,
17583 instantiate all the alternate entry points as well. We do this
17584 by cloning the instantiation of the main entry point, not by
17585 instantiating the template clones. */
17590 {
17592 {
17593 /* Remember to reinstantiate when we're out of SFINAE so the user
17594 can see the errors. */
17596 }
17598 }
17600 }
17602 /* Wrapper for instantiate_template_1. */
17604 tree
17606 {
17607 tree ret;
17612 }
17614 /* Instantiate the alias template TMPL with ARGS. Also push a template
17615 instantiation level, which instantiate_template doesn't do because
17616 functions and variables have sufficient context established by the
17617 callers. */
17619 static tree
17621 {
17628 {
17631 }
17633 args =
17641 /* We can't free this if a pending_template entry or last_error_tinst_level
17642 is pointing at it. */
17648 }
17650 /* PARM is a template parameter pack for FN. Returns true iff
17651 PARM is used in a deducible way in the argument list of FN. */
17653 static bool
17655 {
17658 {
17660 tree packs;
17666 {
17667 /* The template parameter pack is used in a function parameter
17668 pack. If this is the end of the parameter list, the
17669 template parameter pack is deducible. */
17672 else
17673 /* Otherwise, not. Well, it could be deduced from
17674 a non-pack parameter, but doing so would end up with
17675 a deduction mismatch, so don't bother. */
17677 }
17678 }
17679 /* The template parameter pack isn't used in any function parameter
17680 packs, but it might be used deeper, e.g. tuple<Args...>. */
17682 }
17684 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
17685 NARGS elements of the arguments that are being used when calling
17686 it. TARGS is a vector into which the deduced template arguments
17687 are placed.
17689 Returns either a FUNCTION_DECL for the matching specialization of FN or
17690 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
17691 true, diagnostics will be printed to explain why it failed.
17693 If FN is a conversion operator, or we are trying to produce a specific
17694 specialization, RETURN_TYPE is the return type desired.
17696 The EXPLICIT_TARGS are explicit template arguments provided via a
17697 template-id.
17699 The parameter STRICT is one of:
17701 DEDUCE_CALL:
17702 We are deducing arguments for a function call, as in
17703 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
17704 deducing arguments for a call to the result of a conversion
17705 function template, as in [over.call.object].
17707 DEDUCE_CONV:
17708 We are deducing arguments for a conversion function, as in
17709 [temp.deduct.conv].
17711 DEDUCE_EXACT:
17712 We are deducing arguments when doing an explicit instantiation
17713 as in [temp.explicit], when determining an explicit specialization
17714 as in [temp.expl.spec], or when taking the address of a function
17715 template, as in [temp.deduct.funcaddr]. */
17717 tree
17719 tree explicit_targs,
17720 tree targs,
17723 tree return_type,
17724 unification_kind_t strict,
17728 {
17729 tree parms;
17730 tree fntype;
17738 tree tinst;
17744 full_targs = (add_outermost_template_args
17746 targs));
17751 /* In C++0x, it's possible to have a function template whose type depends
17752 on itself recursively. This is most obvious with decltype, but can also
17753 occur with enumeration scope (c++/48969). So we need to catch infinite
17754 recursion and reject the substitution at deduction time; this function
17755 will return error_mark_node for any repeated substitution.
17757 This also catches excessive recursion such as when f<N> depends on
17758 f<N-1> across all integers, and returns error_mark_node for all the
17759 substitutions back up to the initial one.
17761 This is, of course, not reentrant. */
17771 {
17772 /* [temp.deduct]
17774 The specified template arguments must match the template
17775 parameters in kind (i.e., type, nontype, template), and there
17776 must not be more arguments than there are parameters;
17777 otherwise type deduction fails.
17779 Nontype arguments must match the types of the corresponding
17780 nontype template parameters, or must be convertible to the
17781 types of the corresponding nontype parameters as specified in
17782 _temp.arg.nontype_, otherwise type deduction fails.
17784 All references in the function type of the function template
17785 to the corresponding template parameters are replaced by the
17786 specified template argument values. If a substitution in a
17787 template parameter or in the function type of the function
17788 template results in an invalid type, type deduction fails. */
17799 explicit_targs);
17801 /* Adjust any explicit template arguments before entering the
17802 substitution context. */
17803 explicit_targs
17805 complain,
17811 /* Substitute the explicit args into the function type. This is
17812 necessary so that, for instance, explicitly declared function
17813 arguments can match null pointed constants. If we were given
17814 an incomplete set of explicit args, we must not do semantic
17815 processing during substitution as we could create partial
17816 instantiations. */
17818 {
17823 /* Dig out the actual parm. */
17826 {
17829 }
17831 {
17834 }
17837 /* No explicit argument for this template parameter. */
17841 {
17842 /* Mark the argument pack as "incomplete". We could
17843 still deduce more arguments during unification.
17844 We remove this mark in type_unification_real. */
17846 {
17850 }
17852 /* We have some incomplete argument packs. */
17854 }
17855 }
17859 {
17862 }
17865 /* Ignore any access checks; we'll see them again in
17866 instantiate_template and they might have the wrong
17867 access path at this point. */
17879 /* Place the explicitly specified arguments in TARGS. */
17883 }
17885 /* Never do unification on the 'this' parameter. */
17889 {
17890 /* We're deducing for a call to the result of a template conversion
17891 function. The parms we really want are in return_type. */
17895 }
17897 {
17906 }
17908 /* We allow incomplete unification without an error message here
17909 because the standard doesn't seem to explicitly prohibit it. Our
17910 callers must be ready to deal with unification failures in any
17911 event. */
17914 /* If we aren't explaining yet, push tinst context so we can see where
17915 any errors (e.g. from class instantiations triggered by instantiation
17916 of default template arguments) come from. If we are explaining, this
17917 context is redundant. */
17919 {
17922 }
17924 /* type_unification_real will pass back any access checks from default
17925 template argument substitution. */
17937 /* Now that we have bindings for all of the template arguments,
17938 ensure that the arguments deduced for the template template
17939 parameters have compatible template parameter lists. We cannot
17940 check this property before we have deduced all template
17941 arguments, because the template parameter types of a template
17942 template parameter might depend on prior template parameters
17943 deduced after the template template parameter. The following
17944 ill-formed example illustrates this issue:
17946 template<typename T, template<T> class C> void f(C<5>, T);
17948 template<int N> struct X {};
17950 void g() {
17951 f(X<5>(), 5l); // error: template argument deduction fails
17952 }
17954 The template parameter list of 'C' depends on the template type
17955 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
17956 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
17957 time that we deduce 'C'. */
17960 {
17963 }
17965 /* All is well so far. Now, check:
17967 [temp.deduct]
17969 When all template arguments have been deduced, all uses of
17970 template parameters in nondeduced contexts are replaced with
17971 the corresponding deduced argument values. If the
17972 substitution results in an invalid type, as described above,
17973 type deduction fails. */
17976 {
17979 }
17981 /* Also collect access checks from the instantiation. */
17994 /* Now perform any access checks encountered during substitution. */
18001 /* If we're looking for an exact match, check that what we got
18002 is indeed an exact match. It might not be if some template
18003 parameters are used in non-deduced contexts. But don't check
18004 for an exact match if we have dependent template arguments;
18005 in that case we're doing partial ordering, and we already know
18006 that we have two candidates that will provide the actual type. */
18008 {
18012 tree sarg
18018 {
18022 }
18023 }
18027 fail:
18030 {
18032 /* Reset once we're all the way out. */
18034 }
18036 /* We can't free this if a pending_template entry or last_error_tinst_level
18037 is pointing at it. */
18043 }
18045 /* Adjust types before performing type deduction, as described in
18046 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18047 sections are symmetric. PARM is the type of a function parameter
18048 or the return type of the conversion function. ARG is the type of
18049 the argument passed to the call, or the type of the value
18050 initialized with the result of the conversion function.
18051 ARG_EXPR is the original argument expression, which may be null. */
18053 static int
18057 tree arg_expr)
18058 {
18062 {
18067 /* Swap PARM and ARG throughout the remainder of this
18068 function; the handling is precisely symmetric since PARM
18069 will initialize ARG rather than vice versa. */
18074 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18075 too, but here handle it by stripping the reference from PARM
18076 rather than by adding it to ARG. */
18084 /* Nothing else to do in this case. */
18089 }
18092 {
18093 /* [temp.deduct.call]
18095 If P is not a reference type:
18097 --If A is an array type, the pointer type produced by the
18098 array-to-pointer standard conversion (_conv.array_) is
18099 used in place of A for type deduction; otherwise,
18101 --If A is a function type, the pointer type produced by
18102 the function-to-pointer standard conversion
18103 (_conv.func_) is used in place of A for type deduction;
18104 otherwise,
18106 --If A is a cv-qualified type, the top level
18107 cv-qualifiers of A's type are ignored for type
18108 deduction. */
18113 else
18115 }
18117 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
18118 of the form T&&, where T is a template parameter, and the argument
18119 is an lvalue, T is deduced as A& */
18125 /* try_one_overload doesn't provide an arg_expr, but
18126 functions are always lvalues. */
18130 /* [temp.deduct.call]
18132 If P is a cv-qualified type, the top level cv-qualifiers
18133 of P's type are ignored for type deduction. If P is a
18134 reference type, the type referred to by P is used for
18135 type deduction. */
18138 {
18141 }
18143 /* DR 322. For conversion deduction, remove a reference type on parm
18144 too (which has been swapped into ARG). */
18149 }
18151 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18152 template which does contain any deducible template parameters; check if
18153 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18154 unify_one_argument. */
18156 static int
18159 {
18160 tree type;
18164 else
18171 {
18175 }
18177 {
18182 }
18186 else
18188 }
18192 /* Returns true iff the expression EXPR is one from which a template
18193 argument can be deduced. In other words, if it's an undecorated
18194 use of a template non-type parameter. */
18196 static bool
18198 {
18200 }
18202 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18203 deducible way; that is, if it has a max value of <PARM> - 1. */
18205 static bool
18207 {
18216 }
18218 /* Returns true iff the template arguments ARGS use a template parameter
18219 in a deducible way. */
18221 static bool
18223 {
18225 {
18230 else
18231 {
18238 else
18240 }
18243 }
18245 }
18247 /* Returns true iff TYPE contains any deducible references to template
18248 parameters, as per 14.8.2.5. */
18250 static bool
18252 {
18256 /* T
18257 cv-list T
18258 TT<T>
18259 TT<i>
18260 TT<> */
18265 /* T*
18266 T&
18267 T&& */
18271 /* T[integer-constant ]
18272 type [i] */
18277 /* T type ::*
18278 type T::*
18279 T T::*
18280 T (type ::*)()
18281 type (T::*)()
18282 type (type ::*)(T)
18283 type (T::*)(T)
18284 T (type ::*)(T)
18285 T (T::*)()
18286 T (T::*)(T) */
18289 || (uses_deducible_template_parms
18292 /* template-name <T> (where template-name refers to a class template)
18293 template-name <i> (where template-name refers to a class template) */
18300 /* type (T)
18301 T()
18302 T(T) */
18305 {
18314 }
18317 }
18319 /* Subroutine of type_unification_real and unify_pack_expansion to
18320 handle unification of a single P/A pair. Parameters are as
18321 for those functions. */
18323 static int
18327 {
18334 /* We can't deduce anything from this, but we might get all the
18335 template args from other function args. */
18338 /* Implicit conversions (Clause 4) will be performed on a function
18339 argument to convert it to the type of the corresponding function
18340 parameter if the parameter type contains no template-parameters that
18341 participate in template argument deduction. */
18344 /* For function parameters with no deducible template parameters,
18345 just return. We'll check non-dependent conversions later. */
18349 {
18351 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18352 | UNIFY_ALLOW_MORE_CV_QUAL
18366 }
18368 /* We only do these transformations if this is the top-level
18369 parameter_type_list in a call or declaration matching; in other
18370 situations (nested function declarators, template argument lists) we
18371 won't be comparing a type to an expression, and we don't do any type
18372 adjustments. */
18374 {
18376 {
18379 {
18380 /* [temp.deduct.type] A template-argument can be
18381 deduced from a pointer to function or pointer
18382 to member function argument if the set of
18383 overloaded functions does not contain function
18384 templates and at most one of a set of
18385 overloaded functions provides a unique
18386 match. */
18393 }
18399 }
18401 arg_strict |=
18403 }
18404 else
18409 /* For deduction from an init-list we need the actual list. */
18413 }
18415 /* Most parms like fn_type_unification.
18417 If SUBR is 1, we're being called recursively (to unify the
18418 arguments of a function or method parameter of a function
18419 template).
18421 CHECKS is a pointer to a vector of access checks encountered while
18422 substituting default template arguments. */
18424 static int
18426 tree full_targs,
18427 tree xparms,
18431 unification_kind_t strict,
18435 {
18440 tree parms;
18451 /* Reset the number of non-defaulted template arguments contained
18452 in TARGS. */
18455 again:
18463 {
18468 /* For a function parameter pack that occurs at the end of the
18469 parameter-declaration-list, the type A of each remaining
18470 argument of the call is compared with the type P of the
18471 declarator-id of the function parameter pack. */
18477 /* For a function parameter pack that does not occur at the
18478 end of the parameter-declaration-list, the type of the
18479 parameter pack is a non-deduced context. */
18486 explain_p))
18488 }
18493 {
18494 /* Unify the remaining arguments with the pack expansion type. */
18495 tree argvec;
18498 /* Allocate a TREE_VEC and copy in all of the arguments */
18503 /* Copy the parameter into parmvec. */
18509 /* Advance to the end of the list of parameters. */
18511 }
18513 /* Fail if we've reached the end of the parm list, and more args
18514 are present, and the parm list isn't variadic. */
18517 /* Fail if parms are left and they don't have default values and
18518 they aren't all deduced as empty packs (c++/57397). This is
18519 consistent with sufficient_parms_p. */
18522 {
18526 do
18527 {
18530 count++;
18532 }
18536 type_pack_p);
18537 }
18540 {
18541 tsubst_flags_t complain = (explain_p
18542 ? tf_warning_or_error
18546 {
18550 /* Clear the "incomplete" flags on all argument packs now so that
18551 substituting them into later default arguments works. */
18553 {
18556 }
18562 /* If this is an undeduced nontype parameter that depends on
18563 a type parameter, try another pass; its type may have been
18564 deduced from a later argument than the one from which
18565 this parameter can be deduced. */
18569 {
18572 }
18574 /* Core issue #226 (C++0x) [temp.deduct]:
18576 If a template argument has not been deduced, its
18577 default template argument, if any, is used.
18579 When we are in C++98 mode, TREE_PURPOSE will either
18580 be NULL_TREE or ERROR_MARK_NODE, so we do not need
18581 to explicitly check cxx_dialect here. */
18583 /* OK, there is a default argument. Wait until after the
18584 conversion check to do substitution. */
18587 /* If the type parameter is a parameter pack, then it will
18588 be deduced to an empty parameter pack. */
18590 {
18591 tree arg;
18594 {
18598 }
18599 else
18606 }
18609 }
18611 /* DR 1391: All parameters have args, now check non-dependent parms for
18612 convertibility. */
18616 {
18622 /* For a function parameter pack that occurs at the end of the
18623 parameter-declaration-list, the type A of each remaining
18624 argument of the call is compared with the type P of the
18625 declarator-id of the function parameter pack. */
18631 /* For a function parameter pack that does not occur at the
18632 end of the parameter-declaration-list, the type of the
18633 parameter pack is a non-deduced context. */
18642 explain_p))
18644 }
18646 /* Now substitute into the default template arguments. */
18648 {
18674 else
18675 {
18677 /* The position of the first default template argument,
18678 is also the number of non-defaulted arguments in TARGS.
18679 Record that. */
18683 }
18684 }
18688 }
18694 }
18696 /* Subroutine of type_unification_real. Args are like the variables
18697 at the call site. ARG is an overloaded function (or template-id);
18698 we try deducing template args from each of the overloads, and if
18699 only one succeeds, we go with that. Modifies TARGS and returns
18700 true on success. */
18702 static bool
18704 tree targs,
18705 tree parm,
18706 tree arg,
18707 unification_kind_t strict,
18710 {
18717 {
18720 }
18721 else
18725 /* Handle `&x' where `x' is some static or non-static member
18726 function name. */
18732 /* Strip baselink information. */
18737 {
18738 /* If we got some explicit template args, we need to plug them into
18739 the affected templates before we try to unify, in case the
18740 explicit args will completely resolve the templates in question. */
18747 {
18760 {
18765 {
18768 }
18769 }
18772 }
18773 /* If no templates (or more than one) are fully resolved by the
18774 explicit arguments, this template-id is a non-deduced context; it
18775 could still be OK if we deduce all template arguments for the
18776 enclosing call through other arguments. */
18779 }
18782 /* If ARG is, for example, "(0, &f)" then its type will be unknown
18783 -- but the deduction does not succeed because the expression is
18784 not just the function on its own. */
18786 else
18792 {
18795 }
18797 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18798 to function or pointer to member function argument if the set of
18799 overloaded functions does not contain function templates and at most
18800 one of a set of overloaded functions provides a unique match.
18802 So if we found multiple possibilities, we return success but don't
18803 deduce anything. */
18806 {
18810 {
18815 /* Don't forget explicit template arguments in a pack. */
18819 }
18820 }
18825 }
18827 /* Core DR 115: In contexts where deduction is done and fails, or in
18828 contexts where deduction is not done, if a template argument list is
18829 specified and it, along with any default template arguments, identifies
18830 a single function template specialization, then the template-id is an
18831 lvalue for the function template specialization. */
18833 tree
18835 {
18848 {
18851 }
18853 {
18856 }
18858 {
18861 }
18864 {
18868 /* If we got some explicit template args, we need to plug them into
18869 the affected templates before we try to unify, in case the
18870 explicit args will completely resolve the templates in question. */
18878 {
18891 {
18894 {
18897 }
18899 {
18902 }
18903 }
18904 }
18906 {
18914 {
18915 tree base
18918 }
18922 }
18924 /* There were no good options and at least one bad one, so let the
18925 user know what the problem is. */
18927 }
18929 }
18931 /* Subroutine of resolve_overloaded_unification; does deduction for a single
18932 overload. Fills TARGS with any deduced arguments, or error_mark_node if
18933 different overloads deduce different arguments for a given parm.
18934 ADDR_P is true if the expression for which deduction is being
18935 performed was of the form "& fn" rather than simply "fn".
18937 Returns 1 on success. */
18939 static int
18941 tree orig_targs,
18942 tree targs,
18943 tree parm,
18944 tree arg,
18945 unification_kind_t strict,
18949 {
18951 tree tempargs;
18957 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18958 to function or pointer to member function argument if the set of
18959 overloaded functions does not contain function templates and at most
18960 one of a set of overloaded functions provides a unique match.
18962 So if this is a template, just return success. */
18974 /* We don't copy orig_targs for this because if we have already deduced
18975 some template args from previous args, unify would complain when we
18976 try to deduce a template parameter for the same argument, even though
18977 there isn't really a conflict. */
18984 /* First make sure we didn't deduce anything that conflicts with
18985 explicitly specified args. */
18987 {
18994 /* Since we're unifying against ourselves, we will fill in
18995 template args used in the function parm list with our own
18996 template parms. Discard them. */
18999 {
19000 /* Check that the argument at each index of the deduced argument pack
19001 is equivalent to the corresponding explicitly specified argument.
19002 We may have deduced more arguments than were explicitly specified,
19003 and that's OK. */
19019 }
19022 }
19025 {
19030 }
19033 }
19035 /* PARM is a template class (perhaps with unbound template
19036 parameters). ARG is a fully instantiated type. If ARG can be
19037 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19038 TARGS are as for unify. */
19040 static tree
19043 {
19044 tree copy_of_targs;
19051 /* We need to make a new template argument vector for the call to
19052 unify. If we used TARGS, we'd clutter it up with the result of
19053 the attempted unification, even if this class didn't work out.
19054 We also don't want to commit ourselves to all the unifications
19055 we've already done, since unification is supposed to be done on
19056 an argument-by-argument basis. In other words, consider the
19057 following pathological case:
19059 template <int I, int J, int K>
19060 struct S {};
19062 template <int I, int J>
19063 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19065 template <int I, int J, int K>
19066 void f(S<I, J, K>, S<I, I, I>);
19068 void g() {
19069 S<0, 0, 0> s0;
19070 S<0, 1, 2> s2;
19072 f(s0, s2);
19073 }
19075 Now, by the time we consider the unification involving `s2', we
19076 already know that we must have `f<0, 0, 0>'. But, even though
19077 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19078 because there are two ways to unify base classes of S<0, 1, 2>
19079 with S<I, I, I>. If we kept the already deduced knowledge, we
19080 would reject the possibility I=1. */
19083 /* If unification failed, we're done. */
19089 }
19091 /* Given a template type PARM and a class type ARG, find the unique
19092 base type in ARG that is an instance of PARM. We do not examine
19093 ARG itself; only its base-classes. If there is not exactly one
19094 appropriate base class, return NULL_TREE. PARM may be the type of
19095 a partial specialization, as well as a plain template type. Used
19096 by unify. */
19098 static enum template_base_result
19101 {
19103 tree binfo;
19109 {
19110 /* The type could not be completed. */
19113 }
19115 /* Walk in inheritance graph order. The search order is not
19116 important, and this avoids multiple walks of virtual bases. */
19118 {
19123 {
19124 /* If there is more than one satisfactory baseclass, then:
19126 [temp.deduct.call]
19128 If they yield more than one possible deduced A, the type
19129 deduction fails.
19131 applies. */
19133 {
19136 }
19139 }
19140 }
19144 }
19146 /* Returns the level of DECL, which declares a template parameter. */
19148 static int
19150 {
19152 {
19162 }
19164 }
19166 /* Decide whether ARG can be unified with PARM, considering only the
19167 cv-qualifiers of each type, given STRICT as documented for unify.
19168 Returns nonzero iff the unification is OK on that basis. */
19170 static int
19172 {
19178 {
19179 /* Although a CVR qualifier is ignored when being applied to a
19180 substituted template parameter ([8.3.2]/1 for example), that
19181 does not allow us to unify "const T" with "int&" because both
19182 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19183 It is ok when we're allowing additional CV qualifiers
19184 at the outer level [14.8.2.1]/3,1st bullet. */
19194 }
19205 }
19207 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19208 void
19210 {
19214 {
19217 }
19218 else
19219 {
19222 }
19223 }
19225 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19226 do { \
19227 if (unify (TP, TA, P, A, S, EP)) \
19228 return 1; \
19229 } while (0);
19231 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19232 expansion at the end of PACKED_PARMS. Returns 0 if the type
19233 deduction succeeds, 1 otherwise. STRICT is the same as in
19234 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
19235 call argument list. We'll need to adjust the arguments to make them
19236 types. SUBR tells us if this is from a recursive call to
19237 type_unification_real, or for comparing two template argument
19238 lists. */
19240 static int
19244 {
19245 tree parm
19255 /* Determine the parameter packs we will be deducing from the
19256 pattern, and record their current deductions. */
19259 {
19263 /* Determine the index and level of this parameter pack. */
19266 /* Keep track of the parameter packs and their corresponding
19267 argument packs. */
19270 }
19272 /* Loop through all of the arguments that have not yet been
19273 unified and unify each with the pattern. */
19275 {
19276 tree parm;
19280 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19281 or the element of its argument pack at the current index if
19282 this argument was explicitly specified. */
19284 {
19293 {
19296 }
19298 }
19300 /* If we had explicit template arguments, substitute them into the
19301 pattern before deduction. */
19303 {
19304 /* Some arguments might still be unspecified or dependent. */
19312 NULL_TREE);
19317 }
19318 else
19321 /* Unify the pattern with the current argument. */
19323 explain_p))
19326 /* For each parameter pack, collect the deduced value. */
19328 {
19334 }
19335 }
19337 /* Verify that the results of unification with the parameter packs
19338 produce results consistent with what we've seen before, and make
19339 the deduced argument packs available. */
19341 {
19348 /* By default keep the original deduced argument pack.
19349 If necessary, more specific code is going to update the
19350 resulting deduced argument later down in this function. */
19354 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
19355 actually deduce anything. */
19363 {
19364 /* If we had fewer function args than explicit template args,
19365 just use the explicits. */
19370 }
19373 {
19374 tree result;
19375 /* Build the deduced *_ARGUMENT_PACK. */
19377 {
19382 }
19383 else
19388 /* Note the deduced argument packs for this parameter
19389 pack. */
19391 }
19395 {
19396 /* We only had the explicitly-provided arguments before, but
19397 now we have a complete set of arguments. */
19403 }
19404 else
19405 {
19411 /* Inconsistent unification of this parameter pack. */
19413 bad_old_arg,
19414 bad_new_arg);
19415 }
19416 }
19419 }
19421 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
19422 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
19423 parameters and return value are as for unify. */
19425 static int
19429 {
19430 tree parm_max;
19431 tree arg_max;
19435 /* Our representation of array types uses "N - 1" as the
19436 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
19437 not an integer constant. We cannot unify arbitrarily
19438 complex expressions, so we eliminate the MINUS_EXPRs
19439 here. */
19443 {
19446 }
19450 {
19451 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
19452 trying to unify the type of a variable with the type
19453 of a template parameter. For example:
19455 template <unsigned int N>
19456 void f (char (&) [N]);
19457 int g();
19458 void h(int i) {
19459 char a[g(i)];
19460 f(a);
19461 }
19463 Here, the type of the ARG will be "int [g(i)]", and
19464 may be a SAVE_EXPR, etc. */
19468 }
19470 /* If only one of the bounds used a MINUS_EXPR, compensate
19471 by adding one to the other bound. */
19474 integer_type_node,
19475 parm_max,
19476 integer_one_node);
19479 integer_type_node,
19480 arg_max,
19481 integer_one_node);
19485 }
19487 /* Deduce the value of template parameters. TPARMS is the (innermost)
19488 set of template parameters to a template. TARGS is the bindings
19489 for those template parameters, as determined thus far; TARGS may
19490 include template arguments for outer levels of template parameters
19491 as well. PARM is a parameter to a template function, or a
19492 subcomponent of that parameter; ARG is the corresponding argument.
19493 This function attempts to match PARM with ARG in a manner
19494 consistent with the existing assignments in TARGS. If more values
19495 are deduced, then TARGS is updated.
19497 Returns 0 if the type deduction succeeds, 1 otherwise. The
19498 parameter STRICT is a bitwise or of the following flags:
19500 UNIFY_ALLOW_NONE:
19501 Require an exact match between PARM and ARG.
19502 UNIFY_ALLOW_MORE_CV_QUAL:
19503 Allow the deduced ARG to be more cv-qualified (by qualification
19504 conversion) than ARG.
19505 UNIFY_ALLOW_LESS_CV_QUAL:
19506 Allow the deduced ARG to be less cv-qualified than ARG.
19507 UNIFY_ALLOW_DERIVED:
19508 Allow the deduced ARG to be a template base class of ARG,
19509 or a pointer to a template base class of the type pointed to by
19510 ARG.
19511 UNIFY_ALLOW_INTEGER:
19512 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
19513 case for more information.
19514 UNIFY_ALLOW_OUTER_LEVEL:
19515 This is the outermost level of a deduction. Used to determine validity
19516 of qualification conversions. A valid qualification conversion must
19517 have const qualified pointers leading up to the inner type which
19518 requires additional CV quals, except at the outer level, where const
19519 is not required [conv.qual]. It would be normal to set this flag in
19520 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
19521 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
19522 This is the outermost level of a deduction, and PARM can be more CV
19523 qualified at this point.
19524 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
19525 This is the outermost level of a deduction, and PARM can be less CV
19526 qualified at this point. */
19528 static int
19531 {
19533 tree targ;
19534 tree tparm;
19537 /* I don't think this will do the right thing with respect to types.
19538 But the only case I've seen it in so far has been array bounds, where
19539 signedness is the only information lost, and I think that will be
19540 okay. */
19548 /* We can't deduce anything from this, but we might get all the
19549 template args from other function args. */
19552 /* If PARM uses template parameters, then we can't bail out here,
19553 even if ARG == PARM, since we won't record unifications for the
19554 template parameters. We might need them if we're trying to
19555 figure out which of two things is more specialized. */
19559 /* Handle init lists early, so the rest of the function can assume
19560 we're dealing with a type. */
19562 {
19567 /* Replace T with std::initializer_list<T> for deduction. */
19574 /* We can only deduce from an initializer list argument if the
19575 parameter is std::initializer_list or an array; otherwise this
19576 is a non-deduced context. */
19581 else
19582 {
19584 /* Deduction is defined in terms of a single type, so just punt
19585 on the (bizarre) std::initializer_list<T...>. */
19588 }
19591 {
19598 {
19602 /* It should only be possible to get here for a call. */
19604 elt_strict |= maybe_adjust_types_for_deduction
19607 }
19610 explain_p);
19611 }
19615 {
19616 /* Also deduce from the length of the initializer list. */
19623 }
19625 /* If the std::initializer_list<T> deduction worked, replace the
19626 deduced A with std::initializer_list<A>. */
19628 {
19633 }
19635 }
19637 /* Immediately reject some pairs that won't unify because of
19638 cv-qualification mismatches. */
19641 /* It is the elements of the array which hold the cv quals of an array
19642 type, and the elements might be template type parms. We'll check
19643 when we recurse. */
19645 /* We check the cv-qualifiers when unifying with template type
19646 parameters below. We want to allow ARG `const T' to unify with
19647 PARM `T' for example, when computing which of two templates
19648 is more specialized, for example. */
19662 {
19666 /* In a type which contains a nested-name-specifier, template
19667 argument values cannot be deduced for template parameters used
19668 within the nested-name-specifier. */
19680 /* The PARM is not one we're trying to unify. Just check
19681 to see if it matches ARG. */
19682 {
19687 else
19689 }
19696 /* Check for mixed types and values. */
19704 {
19705 /* ARG must be constructed from a template class or a template
19706 template parameter. */
19710 {
19712 /* An alias template name is never deduced. */
19717 tree parm_parms
19718 = DECL_INNERMOST_TEMPLATE_PARMS
19723 /* The resolution to DR150 makes clear that default
19724 arguments for an N-argument may not be used to bind T
19725 to a template template parameter with fewer than N
19726 parameters. It is not safe to permit the binding of
19727 default arguments as an extension, as that may change
19728 the meaning of a conforming program. Consider:
19730 struct Dense { static const unsigned int dim = 1; };
19732 template <template <typename> class View,
19733 typename Block>
19734 void operator+(float, View<Block> const&);
19736 template <typename Block,
19737 unsigned int Dim = Block::dim>
19738 struct Lvalue_proxy { operator float() const; };
19740 void
19741 test_1d (void) {
19742 Lvalue_proxy<Dense> p;
19743 float b;
19744 b + p;
19745 }
19747 Here, if Lvalue_proxy is permitted to bind to View, then
19748 the global operator+ will be used; if they are not, the
19749 Lvalue_proxy will be converted to float. */
19751 full_argvec,
19753 (explain_p
19754 ? tf_warning_or_error
19761 /* Deduce arguments T, i from TT<T> or TT<i>.
19762 We check each element of PARMVEC and ARGVEC individually
19763 rather than the whole TREE_VEC since they can have
19764 different number of elements. */
19771 /* Check if the parameters end in a pack, making them
19772 variadic. */
19778 /* If the template argument list of P contains a pack
19779 expansion that is not the last template argument, the
19780 entire template argument list is a non-deduced
19781 context. */
19790 {
19795 }
19800 DEDUCE_EXACT,
19803 }
19806 /* Fall through to deduce template name. */
19807 }
19811 {
19812 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
19814 /* Simple cases: Value already set, does match or doesn't. */
19819 }
19820 else
19821 {
19822 /* If PARM is `const T' and ARG is only `int', we don't have
19823 a match unless we are allowing additional qualification.
19824 If ARG is `const int' and PARM is just `T' that's OK;
19825 that binds `const int' to `T'. */
19830 /* Consider the case where ARG is `const volatile int' and
19831 PARM is `const T'. Then, T should be `volatile int'. */
19832 arg = cp_build_qualified_type_real
19837 /* Simple cases: Value already set, does match or doesn't. */
19843 /* Make sure that ARG is not a variable-sized array. (Note
19844 that were talking about variable-sized arrays (like
19845 `int[n]'), rather than arrays of unknown size (like
19846 `int[]').) We'll get very confused by such a type since
19847 the bound of the array is not constant, and therefore
19848 not mangleable. Besides, such types are not allowed in
19849 ISO C++, so we can do as we please here. We do allow
19850 them for 'auto' deduction, since that isn't ABI-exposed. */
19854 /* Strip typedefs as in convert_template_argument. */
19856 }
19858 /* If ARG is a parameter pack or an expansion, we cannot unify
19859 against it unless PARM is also a parameter pack. */
19864 /* If the argument deduction results is a METHOD_TYPE,
19865 then there is a problem.
19866 METHOD_TYPE doesn't map to any real C++ type the result of
19867 the deduction can not be of that type. */
19881 {
19882 /* The PARM is not one we're trying to unify. Just check
19883 to see if it matches ARG. */
19889 }
19895 {
19900 }
19902 /* [temp.deduct.type] If, in the declaration of a function template
19903 with a non-type template-parameter, the non-type
19904 template-parameter is used in an expression in the function
19905 parameter-list and, if the corresponding template-argument is
19906 deduced, the template-argument type shall match the type of the
19907 template-parameter exactly, except that a template-argument
19908 deduced from an array bound may be of any integral type.
19909 The non-type parameter might use already deduced type parameters. */
19912 /* Template-parameter dependent expression. Just accept it for now.
19913 It will later be processed in convert_template_argument. */
19914 ;
19919 /* Convert the ARG to the type of PARM; the deduced non-type
19920 template argument must exactly match the types of the
19921 corresponding parameter. */
19924 /* We haven't deduced the type of this parameter yet. Try again
19925 later. */
19927 else
19930 /* If ARG is a parameter pack or an expansion, we cannot unify
19931 against it unless PARM is also a parameter pack. */
19936 {
19939 }
19944 {
19945 /* A pointer-to-member constant can be unified only with
19946 another constant. */
19950 /* Just unify the class member. It would be useless (and possibly
19951 wrong, depending on the strict flags) to unify also
19952 PTRMEM_CST_CLASS, because we want to be sure that both parm and
19953 arg refer to the same variable, even if through different
19954 classes. For instance:
19956 struct A { int x; };
19957 struct B : A { };
19959 Unification of &A::x and &B::x must succeed. */
19962 }
19965 {
19969 /* [temp.deduct.call]
19971 A can be another pointer or pointer to member type that can
19972 be converted to the deduced A via a qualification
19973 conversion (_conv.qual_).
19975 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
19976 This will allow for additional cv-qualification of the
19977 pointed-to types if appropriate. */
19980 /* The derived-to-base conversion only persists through one
19981 level of pointers. */
19986 }
20018 /* We have already checked cv-qualification at the top of the
20019 function. */
20023 /* As far as unification is concerned, this wins. Later checks
20024 will invalidate it if necessary. */
20027 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20028 /* Type INTEGER_CST can come from ordinary constant template args. */
20040 {
20050 /* Check for pack expansions in the parameters. */
20052 {
20054 {
20056 /* We can unify against something with a trailing
20057 parameter pack. */
20059 else
20060 /* [temp.deduct.type]/9: If the template argument list of
20061 P contains a pack expansion that is not the last
20062 template argument, the entire template argument list
20063 is a non-deduced context. */
20065 }
20066 }
20068 /* If we don't have enough arguments to satisfy the parameters
20069 (not counting the pack expression at the end), or we have
20070 too many arguments for a parameter list that doesn't end in
20071 a pack expression, we can't unify. */
20077 /* Unify all of the parameters that precede the (optional)
20078 pack expression. */
20080 {
20085 }
20088 DEDUCE_EXACT,
20091 }
20099 {
20107 }
20112 {
20116 {
20117 /* First, we try to unify the PARM and ARG directly. */
20122 {
20123 /* Fallback to the special case allowed in
20124 [temp.deduct.call]:
20126 If P is a class, and P has the form
20127 template-id, then A can be a derived class of
20128 the deduced A. Likewise, if P is a pointer to
20129 a class of the form template-id, A can be a
20130 pointer to a derived class pointed to by the
20131 deduced A. */
20137 {
20138 /* Don't give the derived diagnostic if we're
20139 already dealing with the same template. */
20140 bool same_template
20146 }
20147 }
20148 }
20152 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20153 Then, we should unify `int' and `U'. */
20155 else
20156 /* There's no chance of unification succeeding. */
20161 }
20168 {
20171 tree a;
20177 /* CV qualifications for methods can never be deduced, they must
20178 match exactly. We need to check them explicitly here,
20179 because type_unification_real treats them as any other
20180 cv-qualified parameter. */
20182 && (!check_cv_quals_for_unify
20202 }
20205 /* Unify a pointer to member with a pointer to member function, which
20206 deduces the type of the member as a function type. */
20208 {
20209 /* Check top-level cv qualifiers */
20217 /* Determine the type of the function we are unifying against. */
20221 }
20240 /* Matched cases are handled by the ARG == PARM test above. */
20244 /* We might get a variable as a non-type template argument in parm if the
20245 corresponding parameter is type-dependent. Make any necessary
20246 adjustments based on whether arg is a reference. */
20250 {
20255 }
20256 /* Now use the normal expression code to check whether they match. */
20267 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20268 or UNDERLYING_TYPE nodes. */
20272 /* Unification fails if we hit an error node. */
20277 {
20282 }
20283 /* FALLTHRU */
20286 /* An unresolved overload is a nondeduced context. */
20290 expr:
20291 /* We must be looking at an expression. This can happen with
20292 something like:
20294 template <int I>
20295 void foo(S<I>, S<I + 2>);
20297 This is a "nondeduced context":
20299 [deduct.type]
20301 The nondeduced contexts are:
20303 --A type that is a template-id in which one or more of
20304 the template-arguments is an expression that references
20305 a template-parameter.
20307 In these cases, we assume deduction succeeded, but don't
20308 actually infer any unifications. */
20313 else
20315 }
20316 }
20317 #undef RECUR_AND_CHECK_FAILURE
20318 \f
20319 /* Note that DECL can be defined in this translation unit, if
20320 required. */
20322 static void
20324 {
20325 tree clone;
20329 }
20331 /* Called if RESULT is explicitly instantiated, or is a member of an
20332 explicitly instantiated class. */
20334 void
20336 {
20339 /* If this entity has already been written out, it's too late to
20340 make any modifications. */
20344 /* For anonymous namespace we don't need to do anything. */
20346 {
20349 }
20352 /* The TREE_PUBLIC flag for function declarations will have been
20353 set correctly by tsubst. */
20356 /* This might have been set by an earlier implicit instantiation. */
20361 else
20362 {
20365 /* Always make artificials weak. */
20368 /* For WIN32 we also want to put explicit instantiations in
20369 linkonce sections. */
20372 }
20374 /* If EXTERN_P, then this function will not be emitted -- unless
20375 followed by an explicit instantiation, at which point its linkage
20376 will be adjusted. If !EXTERN_P, then this function will be
20377 emitted here. In neither circumstance do we want
20378 import_export_decl to adjust the linkage. */
20380 }
20382 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
20383 important template arguments. If any are missing, we check whether
20384 they're important by using error_mark_node for substituting into any
20385 args that were used for partial ordering (the ones between ARGS and END)
20386 and seeing if it bubbles up. */
20388 static bool
20390 {
20395 {
20398 }
20400 {
20404 }
20406 }
20408 /* Given two function templates PAT1 and PAT2, return:
20410 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
20411 -1 if PAT2 is more specialized than PAT1.
20412 0 if neither is more specialized.
20414 LEN indicates the number of parameters we should consider
20415 (defaulted parameters should not be considered).
20417 The 1998 std underspecified function template partial ordering, and
20418 DR214 addresses the issue. We take pairs of arguments, one from
20419 each of the templates, and deduce them against each other. One of
20420 the templates will be more specialized if all the *other*
20421 template's arguments deduce against its arguments and at least one
20422 of its arguments *does* *not* deduce against the other template's
20423 corresponding argument. Deduction is done as for class templates.
20424 The arguments used in deduction have reference and top level cv
20425 qualifiers removed. Iff both arguments were originally reference
20426 types *and* deduction succeeds in both directions, an lvalue reference
20427 wins against an rvalue reference and otherwise the template
20428 with the more cv-qualified argument wins for that pairing (if
20429 neither is more cv-qualified, they both are equal). Unlike regular
20430 deduction, after all the arguments have been deduced in this way,
20431 we do *not* verify the deduced template argument values can be
20432 substituted into non-deduced contexts.
20434 The logic can be a bit confusing here, because we look at deduce1 and
20435 targs1 to see if pat2 is at least as specialized, and vice versa; if we
20436 can find template arguments for pat1 to make arg1 look like arg2, that
20437 means that arg2 is at least as specialized as arg1. */
20439 int
20441 {
20454 /* Remove the this parameter from non-static member functions. If
20455 one is a non-static member function and the other is not a static
20456 member function, remove the first parameter from that function
20457 also. This situation occurs for operator functions where we
20458 locate both a member function (with this pointer) and non-member
20459 operator (with explicit first operand). */
20461 {
20466 }
20468 {
20471 {
20472 len--;
20474 }
20475 }
20477 /* If only one is a conversion operator, they are unordered. */
20481 /* Consider the return type for a conversion function */
20483 {
20486 len++;
20487 }
20489 processing_template_decl++;
20495 /* Stop when an ellipsis is seen. */
20497 {
20508 {
20509 /* When both arguments are pack expansions, we need only
20510 unify the patterns themselves. */
20514 /* This is the last comparison we need to do. */
20516 }
20519 {
20523 }
20526 {
20530 }
20536 {
20542 /* Setup the parameter vector, which contains only ARG1. */
20545 /* Setup the argument vector, which contains the remaining
20546 arguments. */
20555 /* We cannot deduce in the other direction, because ARG1 is
20556 a pack expansion but ARG2 is not. */
20558 }
20560 {
20566 /* Setup the parameter vector, which contains only ARG1. */
20569 /* Setup the argument vector, which contains the remaining
20570 arguments. */
20579 /* We cannot deduce in the other direction, because ARG2 is
20580 a pack expansion but ARG1 is not.*/
20582 }
20584 else
20585 {
20586 /* The normal case, where neither argument is a pack
20587 expansion. */
20594 }
20596 /* If we couldn't deduce arguments for tparms1 to make arg1 match
20597 arg2, then arg2 is not as specialized as arg1. */
20603 /* "If, for a given type, deduction succeeds in both directions
20604 (i.e., the types are identical after the transformations above)
20605 and both P and A were reference types (before being replaced with
20606 the type referred to above):
20607 - if the type from the argument template was an lvalue reference and
20608 the type from the parameter template was not, the argument type is
20609 considered to be more specialized than the other; otherwise,
20610 - if the type from the argument template is more cv-qualified
20611 than the type from the parameter template (as described above),
20612 the argument type is considered to be more specialized than the other;
20613 otherwise,
20614 - neither type is more specialized than the other." */
20617 {
20619 {
20622 else
20624 }
20626 {
20631 }
20632 }
20635 /* We've failed to deduce something in either direction.
20636 These must be unordered. */
20641 /* We have already processed all of the arguments in our
20642 handing of the pack expansion type. */
20647 }
20649 /* "In most cases, all template parameters must have values in order for
20650 deduction to succeed, but for partial ordering purposes a template
20651 parameter may remain without a value provided it is not used in the
20652 types being used for partial ordering."
20654 Thus, if we are missing any of the targs1 we need to substitute into
20655 origs1, then pat2 is not as specialized as pat1. This can happen when
20656 there is a nondeduced context. */
20662 processing_template_decl--;
20664 /* If both deductions succeed, the partial ordering selects the more
20665 constrained template. */
20667 {
20672 }
20674 /* All things being equal, if the next argument is a pack expansion
20675 for one function but not for the other, prefer the
20676 non-variadic function. FIXME this is bogus; see c++/41958. */
20680 {
20683 }
20689 else
20691 }
20693 /* Determine which of two partial specializations of TMPL is more
20694 specialized.
20696 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
20697 to the first partial specialization. The TREE_PURPOSE is the
20698 innermost set of template parameters for the partial
20699 specialization. PAT2 is similar, but for the second template.
20701 Return 1 if the first partial specialization is more specialized;
20702 -1 if the second is more specialized; 0 if neither is more
20703 specialized.
20705 See [temp.class.order] for information about determining which of
20706 two templates is more specialized. */
20708 static int
20710 {
20711 tree targs;
20720 /* Just like what happens for functions, if we are ordering between
20721 different template specializations, we may encounter dependent
20722 types in the arguments, and we need our dependency check functions
20723 to behave correctly. */
20727 {
20730 }
20734 {
20737 }
20740 /* If both deductions succeed, the partial ordering selects the more
20741 constrained template. */
20745 /* In the case of a tie where at least one of the templates
20746 has a parameter pack at the end, the template with the most
20747 non-packed parameters wins. */
20749 && any_deductions
20752 {
20758 /* We don't count the pack expansion at the end. */
20768 }
20771 }
20773 /* Return the template arguments that will produce the function signature
20774 DECL from the function template FN, with the explicit template
20775 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
20776 also match. Return NULL_TREE if no satisfactory arguments could be
20777 found. */
20779 static tree
20781 {
20785 tree decl_arg_types;
20788 tree arg;
20792 /* Never do unification on the 'this' parameter. */
20813 }
20815 /* Return the innermost template arguments that, when applied to a partial
20816 specialization SPEC_TMPL of TMPL, yield the ARGS.
20818 For example, suppose we have:
20820 template <class T, class U> struct S {};
20821 template <class T> struct S<T*, int> {};
20823 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
20824 partial specialization and the ARGS will be {double*, int}. The resulting
20825 vector will be {double}, indicating that `T' is bound to `double'. */
20827 static tree
20829 {
20831 tree spec_args
20834 tree deduced_args;
20835 tree innermost_deduced_args;
20839 {
20843 innermost_deduced_args);
20844 }
20845 else
20860 {
20863 }
20865 /* Verify that nondeduced template arguments agree with the type
20866 obtained from argument deduction.
20868 For example:
20870 struct A { typedef int X; };
20871 template <class T, class U> struct C {};
20872 template <class T> struct C<T, typename T::X> {};
20874 Then with the instantiation `C<A, int>', we can deduce that
20875 `T' is `A' but unify () does not check whether `typename T::X'
20876 is `int'. */
20885 /* We only need to check the innermost arguments; the other
20886 arguments will always agree. */
20891 /* Now that we have bindings for all of the template arguments,
20892 ensure that the arguments deduced for the template template
20893 parameters have compatible template parameter lists. See the use
20894 of template_template_parm_bindings_ok_p in fn_type_unification
20895 for more information. */
20900 }
20902 // Compare two function templates T1 and T2 by deducing bindings
20903 // from one against the other. If both deductions succeed, compare
20904 // constraints to see which is more constrained.
20905 static int
20907 {
20912 {
20915 }
20918 {
20921 }
20923 // If both deductions succeed, then one may be more constrained.
20928 }
20930 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
20931 Return the TREE_LIST node with the most specialized template, if
20932 any. If there is no most specialized template, the error_mark_node
20933 is returned.
20935 Note that this function does not look at, or modify, the
20936 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
20937 returned is one of the elements of INSTANTIATIONS, callers may
20938 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
20939 and retrieve it from the value returned. */
20941 tree
20943 {
20950 {
20955 {
20956 /* Equally specialized, move to next function. If there
20957 is no next function, nothing's most specialized. */
20962 }
20963 }
20966 /* Now verify that champ is better than everything earlier in the
20967 instantiation list. */
20970 {
20973 }
20974 }
20976 processing_template_decl--;
20982 }
20984 /* If DECL is a specialization of some template, return the most
20985 general such template. Otherwise, returns NULL_TREE.
20987 For example, given:
20989 template <class T> struct S { template <class U> void f(U); };
20991 if TMPL is `template <class U> void S<int>::f(U)' this will return
20992 the full template. This function will not trace past partial
20993 specializations, however. For example, given in addition:
20995 template <class T> struct S<T*> { template <class U> void f(U); };
20997 if TMPL is `template <class U> void S<int*>::f(U)' this will return
20998 `template <class T> template <class U> S<T*>::f(U)'. */
21000 tree
21002 {
21004 {
21007 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21008 template friend, or a FIELD_DECL for a capture pack. */
21011 }
21013 /* Look for more and more general templates. */
21015 {
21016 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21017 (See cp-tree.h for details.) */
21026 /* Stop if we run into an explicitly specialized class template. */
21033 }
21036 }
21038 /* Return the most specialized of the template partial specializations
21039 which can produce TARGET, a specialization of some class or variable
21040 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21041 a TEMPLATE_DECL node corresponding to the partial specialization, while
21042 the TREE_PURPOSE is the set of template arguments that must be
21043 substituted into the template pattern in order to generate TARGET.
21045 If the choice of partial specialization is ambiguous, a diagnostic
21046 is issued, and the error_mark_node is returned. If there are no
21047 partial specializations matching TARGET, then NULL_TREE is
21048 returned, indicating that the primary template should be used. */
21050 static tree
21052 {
21054 tree t;
21055 tree champ;
21062 {
21066 }
21068 {
21071 }
21073 {
21077 }
21078 else
21083 /* For determining which partial specialization to use, only the
21084 innermost args are interesting. */
21086 {
21089 }
21092 {
21093 tree spec_args;
21097 {
21098 /* Substitute in the template args from the enclosing class. */
21102 }
21109 {
21113 /* Keep the candidate only if the constraints are satisfied,
21114 or if we're not compiling with concepts. */
21117 {
21120 }
21121 }
21122 }
21132 {
21135 ;
21136 else
21137 {
21139 {
21142 {
21145 }
21146 }
21148 }
21149 }
21153 {
21156 {
21159 }
21160 }
21163 {
21170 else
21174 {
21179 }
21182 }
21185 }
21187 /* Explicitly instantiate DECL. */
21189 void
21191 {
21196 /* An error occurred, for which grokdeclarator has already issued
21197 an appropriate message. */
21200 {
21203 }
21209 {
21210 /* There is an asymmetry here in the way VAR_DECLs and
21211 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21212 the latter, the DECL we get back will be marked as a
21213 template instantiation, and the appropriate
21214 DECL_TEMPLATE_INFO will be set up. This does not happen for
21215 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21216 should handle VAR_DECLs as it currently handles
21217 FUNCTION_DECLs. */
21219 {
21222 }
21225 {
21228 }
21230 {
21235 }
21236 }
21238 {
21241 }
21242 else
21245 /* Check for various error cases. Note that if the explicit
21246 instantiation is valid the RESULT will currently be marked as an
21247 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21248 until we get here. */
21251 {
21252 /* DR 259 [temp.spec].
21254 Both an explicit instantiation and a declaration of an explicit
21255 specialization shall not appear in a program unless the explicit
21256 instantiation follows a declaration of the explicit specialization.
21258 For a given set of template parameters, if an explicit
21259 instantiation of a template appears after a declaration of an
21260 explicit specialization for that template, the explicit
21261 instantiation has no effect. */
21263 }
21265 {
21266 /* [temp.spec]
21268 No program shall explicitly instantiate any template more
21269 than once.
21271 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21272 the first instantiation was `extern' and the second is not,
21273 and EXTERN_P for the opposite case. */
21276 /* If an "extern" explicit instantiation follows an ordinary
21277 explicit instantiation, the template is instantiated. */
21280 }
21282 {
21285 }
21287 {
21290 }
21293 ;
21295 {
21298 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21301 }
21302 else
21310 }
21312 static void
21314 {
21320 {
21323 }
21324 }
21326 /* Called from do_type_instantiation through binding_table_foreach to
21327 do recursive instantiation for the type bound in ENTRY. */
21328 static void
21330 {
21336 }
21338 /* Called from do_type_instantiation to instantiate a member
21339 (a member function or a static member variable) of an
21340 explicitly instantiated class template. */
21341 static void
21343 {
21348 }
21350 /* Perform an explicit instantiation of template class T. STORAGE, if
21351 non-null, is the RID for extern, inline or static. COMPLAIN is
21352 nonzero if this is called from the parser, zero if called recursively,
21353 since the standard is unclear (as detailed below). */
21355 void
21357 {
21367 {
21368 tree tmpl =
21372 else
21375 }
21380 {
21383 t);
21385 }
21388 {
21390 {
21392 {
21395 "ISO C++ 1998 forbids the use of %<extern%> on "
21397 }
21398 else
21400 "ISO C++ forbids the use of %qE"
21402 }
21410 else
21411 {
21413 storage);
21415 }
21416 }
21419 {
21420 /* DR 259 [temp.spec].
21422 Both an explicit instantiation and a declaration of an explicit
21423 specialization shall not appear in a program unless the explicit
21424 instantiation follows a declaration of the explicit specialization.
21426 For a given set of template parameters, if an explicit
21427 instantiation of a template appears after a declaration of an
21428 explicit specialization for that template, the explicit
21429 instantiation has no effect. */
21431 }
21433 {
21434 /* [temp.spec]
21436 No program shall explicitly instantiate any template more
21437 than once.
21439 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
21440 instantiation was `extern'. If EXTERN_P then the second is.
21441 These cases are OK. */
21448 /* If we've already instantiated the template, just return now. */
21451 }
21459 {
21460 tree tmp;
21462 /* In contrast to implicit instantiation, where only the
21463 declarations, and not the definitions, of members are
21464 instantiated, we have here:
21466 [temp.explicit]
21468 The explicit instantiation of a class template specialization
21469 implies the instantiation of all of its members not
21470 previously explicitly specialized in the translation unit
21471 containing the explicit instantiation.
21473 Of course, we can't instantiate member template classes, since
21474 we don't have any arguments for them. Note that the standard
21475 is unclear on whether the instantiation of the members are
21476 *explicit* instantiations or not. However, the most natural
21477 interpretation is that it should be an explicit instantiation. */
21492 }
21493 }
21495 /* Given a function DECL, which is a specialization of TMPL, modify
21496 DECL to be a re-instantiation of TMPL with the same template
21497 arguments. TMPL should be the template into which tsubst'ing
21498 should occur for DECL, not the most general template.
21500 One reason for doing this is a scenario like this:
21502 template <class T>
21503 void f(const T&, int i);
21505 void g() { f(3, 7); }
21507 template <class T>
21508 void f(const T& t, const int i) { }
21510 Note that when the template is first instantiated, with
21511 instantiate_template, the resulting DECL will have no name for the
21512 first parameter, and the wrong type for the second. So, when we go
21513 to instantiate the DECL, we regenerate it. */
21515 static void
21517 {
21518 /* The arguments used to instantiate DECL, from the most general
21519 template. */
21520 tree code_pattern;
21524 /* Make sure that we can see identifiers, and compute access
21525 correctly. */
21529 {
21530 tree decl_parm;
21531 tree pattern_parm;
21532 tree specs;
21546 specs);
21548 /* Merge parameter declarations. */
21551 pattern_parm
21555 {
21556 tree parm_type;
21557 tree attributes;
21562 NULL_TREE);
21568 {
21571 }
21574 }
21575 /* Merge any parameters that match with the function parameter
21576 pack. */
21578 {
21580 tree expanded_types;
21581 /* Expand the TYPE_PACK_EXPANSION that provides the types for
21582 the parameters in this function parameter pack. */
21587 {
21588 tree parm_type;
21589 tree attributes;
21592 /* Rename the parameter to include the index. */
21601 {
21604 }
21606 }
21607 }
21608 /* Merge additional specifiers from the CODE_PATTERN. */
21612 }
21614 {
21622 }
21623 else
21627 }
21629 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
21630 substituted to get DECL. */
21632 tree
21634 {
21637 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
21638 for the instantiation. This is not always the most general
21639 template. Consider, for example:
21641 template <class T>
21642 struct S { template <class U> void f();
21643 template <> void f<int>(); };
21645 and an instantiation of S<double>::f<int>. We want TD to be the
21646 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
21648 more general template. */
21650 /* We must also deal with friend templates. Given:
21652 template <class T> struct S {
21653 template <class U> friend void f() {};
21654 };
21656 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
21657 so far as the language is concerned, but that's still
21658 where we get the pattern for the instantiation from. On
21659 other hand, if the definition comes outside the class, say:
21661 template <class T> struct S {
21662 template <class U> friend void f();
21663 };
21664 template <class U> friend void f() {}
21666 we don't need to look any further. That's what the check for
21667 DECL_INITIAL is for. */
21671 {
21672 /* The present template, TD, should not be a definition. If it
21673 were a definition, we should be using it! Note that we
21674 cannot restructure the loop to just keep going until we find
21675 a template with a definition, since that might go too far if
21676 a specialization was declared, but not defined. */
21678 /* Fetch the more general template. */
21680 }
21683 }
21685 /* Returns true if we need to instantiate this template instance even if we
21686 know we aren't going to emit it. */
21688 bool
21690 {
21691 /* We always instantiate inline functions so that we can inline them. An
21692 explicit instantiation declaration prohibits implicit instantiation of
21693 non-inline functions. With high levels of optimization, we would
21694 normally inline non-inline functions -- but we're not allowed to do
21695 that for "extern template" functions. Therefore, we check
21696 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
21700 /* And we need to instantiate static data members so that
21701 their initializers are available in integral constant
21702 expressions. */
21705 }
21707 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
21708 instantiate it now, modifying TREE_TYPE (fn). */
21710 void
21712 {
21715 /* Don't instantiate a noexcept-specification from template context. */
21730 {
21734 {
21749 }
21750 else
21754 }
21757 {
21760 else
21762 }
21763 }
21765 /* Produce the definition of D, a _DECL generated from a template. If
21766 DEFER_OK is nonzero, then we don't have to actually do the
21767 instantiation now; we just have to do it sometime. Normally it is
21768 an error if this is an explicit instantiation but D is undefined.
21769 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
21770 explicitly instantiated class template. */
21772 tree
21775 {
21777 tree gen_args;
21778 tree args;
21779 tree td;
21780 tree code_pattern;
21781 tree spec;
21782 tree gen_tmpl;
21789 tree fn_context;
21792 /* This function should only be used to instantiate templates for
21793 functions and static member variables. */
21796 /* A concept is never instantiated. */
21799 /* Variables are never deferred; if instantiation is required, they
21800 are instantiated right away. That allows for better code in the
21801 case that an expression refers to the value of the variable --
21802 if the variable has a constant value the referring expression can
21803 take advantage of that fact. */
21808 /* Don't instantiate cloned functions. Instead, instantiate the
21809 functions they cloned. */
21817 /* D has already been instantiated or explicitly specialized, so
21818 there's nothing for us to do here.
21820 It might seem reasonable to check whether or not D is an explicit
21821 instantiation, and, if so, stop here. But when an explicit
21822 instantiation is deferred until the end of the compilation,
21823 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
21824 the instantiation. */
21827 /* Check to see whether we know that this template will be
21828 instantiated in some other file, as with "extern template"
21829 extension. */
21832 /* In general, we do not instantiate such templates. */
21840 /* We should already have the extra args. */
21843 /* And what's in the hash table should match D. */
21847 /* This needs to happen before any tsubsting. */
21853 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
21854 for the instantiation. */
21859 {
21860 /* Look up an explicit specialization, if any. */
21864 {
21867 }
21868 }
21872 /* We should never be trying to instantiate a member of a class
21873 template or partial specialization. */
21878 /* In the case of a friend template whose definition is provided
21879 outside the class, we may have too many arguments. Drop the
21880 ones we don't need. The same is true for specializations. */
21881 args = get_innermost_template_args
21885 {
21891 }
21892 else
21893 {
21897 else
21899 }
21901 /* We may be in the middle of deferred access check. Disable it now. */
21904 /* Unless an explicit instantiation directive has already determined
21905 the linkage of D, remember that a definition is available for
21906 this entity. */
21916 /* If D is a member of an explicitly instantiated class template,
21917 and no definition is available, treat it like an implicit
21918 instantiation. */
21921 {
21922 /* Leave linkage flags alone on instantiations with anonymous
21923 visibility. */
21925 {
21928 }
21930 }
21932 /* Defer all other templates, unless we have been explicitly
21933 forbidden from doing so. */
21935 template. */
21936 ! pattern_defined
21937 /* If it's OK to postpone instantiation, do so. */
21938 || defer_ok
21939 /* If this is a static data member that will be defined
21940 elsewhere, we don't want to instantiate the entire data
21941 member, but we do want to instantiate the initializer so that
21942 we can substitute that elsewhere. */
21944 /* Handle here a deleted function too, avoid generating
21945 its body (c++/61080). */
21947 {
21948 /* The definition of the static data member is now required so
21949 we must substitute the initializer. */
21953 {
21954 tree ns;
21955 tree init;
21964 args,
21967 /* If instantiating the initializer involved instantiating this
21968 again, don't call cp_finish_decl twice. */
21970 {
21971 /* Make sure the initializer is still constant, in case of
21972 circular dependency (template/instantiate6.C). */
21973 const_init
21977 LOOKUP_ONLYCONVERTING);
21978 }
21982 }
21984 /* We restore the source position here because it's used by
21985 add_pending_template. */
21991 /* [temp.explicit]
21993 The definition of a non-exported function template, a
21994 non-exported member function template, or a non-exported
21995 member function or static data member of a class template
21996 shall be present in every translation unit in which it is
21997 explicitly instantiated. */
22001 /* If we're in unevaluated context, we just wanted to get the
22002 constant value; this isn't an odr use, so don't queue
22003 a full instantiation. */
22006 /* ??? Historically, we have instantiated inline functions, even
22007 when marked as "extern template". */
22011 }
22012 /* Tell the repository that D is available in this translation unit
22013 -- and see if it is supposed to be instantiated here. */
22015 {
22016 /* In a PCH file, despite the fact that the repository hasn't
22017 requested instantiation in the PCH it is still possible that
22018 an instantiation will be required in a file that includes the
22019 PCH. */
22022 /* Instantiate inline functions so that the inliner can do its
22023 job, even though we'll not be emitting a copy of this
22024 function. */
22027 }
22037 else
22038 {
22043 }
22045 /* Mark D as instantiated so that recursive calls to
22046 instantiate_decl do not try to instantiate it again. */
22049 /* Regenerate the declaration in case the template has been modified
22050 by a subsequent redeclaration. */
22053 /* We already set the file and line above. Reset them now in case
22054 they changed as a result of calling regenerate_decl_from_template. */
22058 {
22059 tree init;
22062 /* Clear out DECL_RTL; whatever was there before may not be right
22063 since we've reset the type of the declaration. */
22067 /* The initializer is placed in DECL_INITIAL by
22068 regenerate_decl_from_template so we don't need to
22069 push/pop_access_scope again here. Pull it out so that
22070 cp_finish_decl can process it. */
22075 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22076 initializer. That function will defer actual emission until
22077 we have a chance to determine linkage. */
22080 /* Enter the scope of D so that access-checking works correctly. */
22093 }
22097 {
22099 tree tmpl_parm;
22100 tree spec_parm;
22103 /* Save away the current list, in case we are instantiating one
22104 template from within the body of another. */
22107 /* Set up the list of local specializations. */
22110 /* Set up context. */
22114 else
22117 /* Some typedefs referenced from within the template code need to be
22118 access checked at template instantiation time, i.e now. These
22119 types were added to the template at parsing time. Let's get those
22120 and perform the access checks then. */
22122 args);
22124 /* Create substitution entries for the parameters. */
22128 {
22132 }
22134 {
22136 {
22139 }
22140 else
22141 {
22142 /* Register the (value) argument pack as a specialization of
22143 TMPL_PARM, then move on. */
22146 }
22147 }
22150 /* Substitute into the body of the function. */
22154 else
22155 {
22160 /* Set the current input_location to the end of the function
22161 so that finish_function knows where we are. */
22162 input_location
22165 /* Remember if we saw an infinite loop in the template. */
22166 current_function_infinite_loop
22168 }
22170 /* We don't need the local specializations any more. */
22174 /* Finish the function. */
22178 else
22179 {
22182 }
22186 }
22188 /* We're not deferring instantiation any more. */
22196 out:
22208 }
22210 /* Run through the list of templates that we wish we could
22211 instantiate, and instantiate any we can. RETRIES is the
22212 number of times we retry pending template instantiation. */
22214 void
22216 {
22220 /* Instantiating templates may trigger vtable generation. This in turn
22221 may require further template instantiations. We place a limit here
22222 to avoid infinite loop. */
22224 {
22228 "template instantiation depth exceeds maximum of %d"
22229 " instantiating %q+D, possibly from virtual table generation"
22233 /* Pretend that we defined it. */
22236 }
22238 do
22239 {
22244 {
22249 {
22250 tree fn;
22253 {
22257 fn;
22265 }
22268 }
22269 else
22270 {
22273 {
22274 instantiation
22280 }
22284 }
22287 /* If INSTANTIATION has been instantiated, then we don't
22288 need to consider it again in the future. */
22290 else
22291 {
22294 }
22297 }
22299 }
22303 }
22305 /* Substitute ARGVEC into T, which is a list of initializers for
22306 either base class or a non-static data member. The TREE_PURPOSEs
22307 are DECLs, and the TREE_VALUEs are the initializer values. Used by
22308 instantiate_decl. */
22310 static tree
22312 {
22316 {
22317 tree decl;
22318 tree init;
22324 {
22325 tree expr;
22326 tree arg;
22328 /* Expand the base class expansion type into separate base
22329 classes. */
22331 tf_warning_or_error,
22332 NULL_TREE);
22336 /* We'll be building separate TREE_LISTs of arguments for
22337 each base. */
22343 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
22344 expand each argument in the TREE_VALUE of t. */
22351 /* VOID_TYPE_NODE is used to indicate
22352 value-initialization. */
22353 {
22356 }
22357 else
22358 {
22359 /* Substitute parameter packs into each argument in the
22360 TREE_LIST. */
22363 {
22364 tree expanded_exprs;
22366 /* Expand the argument. */
22368 expanded_exprs
22370 tf_warning_or_error,
22371 NULL_TREE);
22375 /* Prepend each of the expanded expressions to the
22376 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
22378 {
22383 }
22384 }
22387 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
22388 since we built them backwards. */
22390 {
22393 }
22394 }
22395 }
22398 {
22400 {
22404 }
22405 else
22406 {
22407 tree tmp;
22422 /* If we had an initializer but it instantiated to nothing,
22423 value-initialize the object. This will only occur when
22424 the initializer was a pack expansion where the parameter
22425 packs used in that expansion were of length zero. */
22428 }
22431 {
22435 }
22436 }
22437 }
22439 }
22441 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
22443 static void
22445 {
22450 else
22452 }
22454 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
22455 is the instantiation (which should have been created with
22456 start_enum) and ARGS are the template arguments to use. */
22458 static void
22460 {
22461 tree e;
22467 {
22468 tree value;
22469 tree decl;
22472 /* Note that in a template enum, the TREE_VALUE is the
22473 CONST_DECL, not the corresponding INTEGER_CST. */
22478 /* Give this enumeration constant the correct access. */
22481 /* Actually build the enumerator itself. Here we're assuming that
22482 enumerators can't have dependent attributes. */
22485 }
22495 }
22497 /* DECL is a FUNCTION_DECL that is a template specialization. Return
22498 its type -- but without substituting the innermost set of template
22499 arguments. So, innermost set of template parameters will appear in
22500 the type. */
22502 tree
22504 {
22505 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
22507 }
22509 /* Return truthvalue if we're processing a template different from
22510 the last one involved in diagnostics. */
22511 bool
22513 {
22515 }
22517 /* Remember current template involved in diagnostics. */
22518 void
22520 {
22522 }
22526 {
22528 }
22530 /* Return TRUE if current_function_decl is being instantiated, false
22531 otherwise. */
22533 bool
22535 {
22538 }
22540 /* [temp.param] Check that template non-type parm TYPE is of an allowable
22541 type. Return zero for ok, nonzero for disallowed. Issue error and
22542 warning messages under control of COMPLAIN. */
22544 static int
22546 {
22561 /* A bound template template parm could later be instantiated to have a valid
22562 nontype parm type via an alias template. */
22568 {
22571 else
22573 type);
22574 }
22576 }
22578 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
22579 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
22581 static bool
22583 {
22584 tree scope;
22586 /* [temp.dep.type]
22588 A type is dependent if it is:
22590 -- a template parameter. Template template parameters are types
22591 for us (since TYPE_P holds true for them) so we handle
22592 them here. */
22596 /* -- a qualified-id with a nested-name-specifier which contains a
22597 class-name that names a dependent type or whose unqualified-id
22598 names a dependent type. */
22602 /* An alias template specialization can be dependent even if the
22603 resulting type is not. */
22607 /* -- a cv-qualified type where the cv-unqualified type is
22608 dependent.
22609 No code is necessary for this bullet; the code below handles
22610 cv-qualified types, and we don't want to strip aliases with
22611 TYPE_MAIN_VARIANT because of DR 1558. */
22612 /* -- a compound type constructed from any dependent type. */
22622 {
22623 tree arg_type;
22628 arg_type;
22633 }
22634 /* -- an array type constructed from any dependent type or whose
22635 size is specified by a constant expression that is
22636 value-dependent.
22638 We checked for type- and value-dependence of the bounds in
22639 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
22641 {
22646 }
22648 /* -- a template-id in which either the template name is a template
22649 parameter ... */
22652 /* ... or any of the template arguments is a dependent type or
22653 an expression that is type-dependent or value-dependent. */
22655 && (any_dependent_template_arguments_p
22659 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
22660 dependent; if the argument of the `typeof' expression is not
22661 type-dependent, then it should already been have resolved. */
22667 /* A template argument pack is dependent if any of its packed
22668 arguments are. */
22670 {
22676 }
22678 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
22679 be template parameters. */
22686 /* The standard does not specifically mention types that are local
22687 to template functions or local classes, but they should be
22688 considered dependent too. For example:
22690 template <int I> void f() {
22691 enum E { a = I };
22692 S<sizeof (E)> s;
22693 }
22695 The size of `E' cannot be known until the value of `I' has been
22696 determined. Therefore, `E' must be considered dependent. */
22700 /* Don't use type_dependent_expression_p here, as it can lead
22701 to infinite recursion trying to determine whether a lambda
22702 nested in a lambda is dependent (c++/47687). */
22706 && (any_dependent_template_arguments_p
22710 /* Other types are non-dependent. */
22712 }
22714 /* Returns TRUE if TYPE is dependent, in the sense of
22715 [temp.dep.type]. Note that a NULL type is considered dependent. */
22717 bool
22719 {
22720 /* If there are no template parameters in scope, then there can't be
22721 any dependent types. */
22723 {
22724 /* If we are not processing a template, then nobody should be
22725 providing us with a dependent type. */
22729 }
22731 /* If the type is NULL, we have not computed a type for the entity
22732 in question; in that case, the type is dependent. */
22736 /* Erroneous types can be considered non-dependent. */
22740 /* If we have not already computed the appropriate value for TYPE,
22741 do so now. */
22743 {
22746 }
22749 }
22751 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
22752 lookup. In other words, a dependent type that is not the current
22753 instantiation. */
22755 bool
22757 {
22760 }
22762 /* T is a SCOPE_REF; return whether we need to consider it
22763 instantiation-dependent so that we can check access at instantiation
22764 time even though we know which member it resolves to. */
22766 static bool
22768 {
22774 else
22776 }
22778 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
22779 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
22780 expression. */
22782 /* Note that this predicate is not appropriate for general expressions;
22783 only constant expressions (that satisfy potential_constant_expression)
22784 can be tested for value dependence. */
22786 bool
22788 {
22792 /* A name declared with a dependent type. */
22797 {
22799 /* A dependent member function of the current instantiation. */
22803 /* A dependent member function of the current instantiation. */
22810 /* A name that has not been looked up -- must be dependent. */
22814 /* A non-type template parm. */
22818 /* A non-type template parm. */
22824 /* A constant with literal type and is initialized
22825 with an expression that is value-dependent.
22827 Note that a non-dependent parenthesized initializer will have
22828 already been replaced with its constant value, so if we see
22829 a TREE_LIST it must be dependent. */
22833 /* cp_finish_decl doesn't fold reference initializers. */
22845 /* These expressions are value-dependent if the type to which
22846 the cast occurs is dependent or the expression being casted
22847 is value-dependent. */
22848 {
22854 /* A functional cast has a list of operands. */
22857 {
22858 /* If there are no operands, it must be an expression such
22859 as "int()". This should not happen for aggregate types
22860 because it would form non-constant expressions. */
22865 }
22871 }
22876 /* FALLTHRU */
22879 /* A `sizeof' expression is value-dependent if the operand is
22880 type-dependent or is a pack expansion. */
22889 /* An 'encode' expression is value-dependent if the operand is
22890 type-dependent. */
22899 /* All instantiation-dependent expressions should also be considered
22900 value-dependent. */
22908 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
22909 is value-dependent. */
22910 {
22919 }
22922 {
22926 }
22937 {
22941 }
22944 /* Treat all requires-expressions as value-dependent so
22945 we don't try to fold them. */
22952 {
22959 {
22961 /* In a call to a constexpr member function, look through the
22962 implicit ADDR_EXPR on the object argument so that it doesn't
22963 cause the call to be considered value-dependent. We also
22964 look through it in potential_constant_expression. */
22971 }
22973 }
22976 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
22977 type-dependent. */
22982 {
22984 tree val;
22991 }
22994 /* Treat a GNU statement expression as dependent to avoid crashing
22995 under instantiate_non_dependent_expr; it can't be constant. */
22999 /* A constant expression is value-dependent if any subexpression is
23000 value-dependent. */
23002 {
23009 {
23013 {
23016 /* In some cases, some of the operands may be missing.l
23017 (For example, in the case of PREDECREMENT_EXPR, the
23018 amount to increment by may be missing.) That doesn't
23019 make the expression dependent. */
23022 }
23023 }
23027 }
23029 }
23031 /* The expression is not value-dependent. */
23033 }
23035 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23036 [temp.dep.expr]. Note that an expression with no type is
23037 considered dependent. Other parts of the compiler arrange for an
23038 expression with type-dependent subexpressions to have no type, so
23039 this function doesn't have to be fully recursive. */
23041 bool
23043 {
23050 /* An unresolved name is always dependent. */
23056 /* A fold expression is type-dependent. */
23063 /* Some expression forms are never type-dependent. */
23077 /* The types of these expressions depends only on the type to which
23078 the cast occurs. */
23087 /* The types of these expressions depends only on the type created
23088 by the expression. */
23091 {
23092 /* For NEW_EXPR tree nodes created inside a template, either
23093 the object type itself or a TREE_LIST may appear as the
23094 operand 1. */
23097 /* This is an array type. We need to check array dimensions
23098 as well. */
23100 || value_dependent_expression_p
23102 else
23104 }
23107 {
23111 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23112 contains an identifier associated by name lookup with one or more
23113 declarations declared with a dependent type, or...a
23114 nested-name-specifier or qualified-id that names a member of an
23115 unknown specialization. */
23118 }
23128 {
23129 tree elt;
23133 {
23136 }
23138 }
23140 /* A static data member of the current instantiation with incomplete
23141 array type is type-dependent, as the definition and specializations
23142 can have different bounds. */
23149 /* An array of unknown bound depending on a variadic parameter, eg:
23151 template<typename... Args>
23152 void foo (Args... args)
23153 {
23154 int arr[] = { args... };
23155 }
23157 template<int... vals>
23158 void bar ()
23159 {
23160 int arr[] = { vals... };
23161 }
23163 If the array has no length and has an initializer, it must be that
23164 we couldn't determine its length in cp_complete_array_type because
23165 it is dependent. */
23172 /* A function or variable template-id is type-dependent if it has any
23173 dependent template arguments. Note that we only consider the innermost
23174 template arguments here, since those are the ones that come from the
23175 template-id; the template arguments for the enclosing class do not make it
23176 type-dependent, they only make a member function value-dependent. */
23181 && (any_dependent_template_arguments_p
23185 /* Always dependent, on the number of arguments if nothing else. */
23190 {
23195 {
23201 }
23202 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23207 {
23212 }
23215 {
23222 }
23228 {
23232 }
23234 }
23238 /* Dependent type attributes might not have made it from the decl to
23239 the type yet. */
23245 }
23247 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23248 type-dependent if the expression refers to a member of the current
23249 instantiation and the type of the referenced member is dependent, or the
23250 class member access expression refers to a member of an unknown
23251 specialization.
23253 This function returns true if the OBJECT in such a class member access
23254 expression is of an unknown specialization. */
23256 bool
23258 {
23261 }
23263 /* walk_tree callback function for instantiation_dependent_expression_p,
23264 below. Returns non-zero if a dependent subexpression is found. */
23266 static tree
23269 {
23271 {
23272 /* We don't have to worry about decltype currently because decltype
23273 of an instantiation-dependent expr is a dependent type. This
23274 might change depending on the resolution of DR 1172. */
23277 }
23280 {
23281 /* Don't treat an argument list as dependent just because it has no
23282 TREE_TYPE. */
23290 /* Handle expressions with type operands. */
23295 {
23300 {
23303 else
23304 {
23307 }
23308 }
23310 }
23314 /* In a template, finish_class_member_access_expr creates a
23315 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
23316 type-dependent, so that we can check access control at
23317 instantiation time (PR 42277). See also Core issue 1273. */
23324 else
23327 /* Treat statement-expressions as dependent. */
23331 /* Treat requires-expressions as dependent. */
23336 /* Treat calls to function concepts as dependent. */
23342 /* And variable concepts. */
23349 }
23353 else
23355 }
23357 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
23358 sense defined by the ABI:
23360 "An expression is instantiation-dependent if it is type-dependent
23361 or value-dependent, or it has a subexpression that is type-dependent
23362 or value-dependent."
23364 Except don't actually check value-dependence for unevaluated expressions,
23365 because in sizeof(i) we don't care about the value of i. Checking
23366 type-dependence will in turn check value-dependence of array bounds/template
23367 arguments as needed. */
23369 bool
23371 {
23372 tree result;
23383 }
23385 /* As above, but also check value-dependence of the expression as a whole. */
23387 bool
23389 {
23392 }
23394 /* Like type_dependent_expression_p, but it also works while not processing
23395 a template definition, i.e. during substitution or mangling. */
23397 bool
23399 {
23405 }
23407 /* Returns TRUE if ARGS contains a type-dependent expression. */
23409 bool
23411 {
23413 tree arg;
23416 {
23419 }
23421 }
23423 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23424 expressions) contains any type-dependent expressions. */
23426 bool
23428 {
23434 }
23436 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23437 expressions) contains any value-dependent expressions. */
23439 bool
23441 {
23447 }
23449 /* Returns TRUE if the ARG (a template argument) is dependent. */
23451 bool
23453 {
23457 /* Assume a template argument that was wrongly written by the user
23458 is dependent. This is consistent with what
23459 any_dependent_template_arguments_p [that calls this function]
23460 does. */
23470 {
23473 /* A member template of a dependent class is not necessarily
23474 type-dependent, but it is a dependent template argument because it
23475 will be a member of an unknown specialization to that template. */
23478 }
23480 {
23484 {
23487 }
23490 }
23493 else
23496 }
23498 /* Returns true if ARGS (a collection of template arguments) contains
23499 any types that require structural equality testing. */
23501 bool
23503 {
23513 {
23516 {
23522 {
23523 /* Look inside the argument pack. */
23526 }
23529 {
23542 }
23543 }
23544 }
23547 }
23549 /* Returns true if ARGS (a collection of template arguments) contains
23550 any dependent arguments. */
23552 bool
23554 {
23564 {
23569 }
23572 }
23574 /* Returns TRUE if the template TMPL is type-dependent. */
23576 bool
23578 {
23580 {
23582 {
23586 }
23588 }
23590 /* Template template parameters are dependent. */
23594 /* So are names that have not been looked up. */
23598 }
23600 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
23602 bool
23604 {
23607 }
23609 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
23610 are dependent. */
23612 bool
23614 {
23621 {
23643 {
23647 }
23651 {
23655 {
23660 }
23661 }
23662 }
23665 }
23667 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
23668 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
23669 no such TYPE can be found. Note that this function peers inside
23670 uninstantiated templates and therefore should be used only in
23671 extremely limited situations. ONLY_CURRENT_P restricts this
23672 peering to the currently open classes hierarchy (which is required
23673 when comparing types). */
23675 tree
23677 {
23678 tree scope;
23679 tree name;
23680 tree decl;
23682 tree pushed_scope;
23683 tree result;
23688 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
23689 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
23690 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
23691 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
23692 identifier of the TYPENAME_TYPE anymore.
23693 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
23694 TYPENAME_TYPE instead, we avoid messing up with a possible
23695 typedef variant case. */
23698 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
23699 it first before we can figure out what NAME refers to. */
23701 {
23703 /* Given a class template A with a dependent base with nested type C,
23704 typedef typename A::C::C C will land us here, as trying to resolve
23705 the initial A::C leads to the local C typedef, which leads back to
23706 A::C::C. So we break the recursion now. */
23708 else
23710 }
23711 /* If we don't know what SCOPE refers to, then we cannot resolve the
23712 TYPENAME_TYPE. */
23715 /* If this is a typedef, we don't want to look inside (c++/11987). */
23718 /* If SCOPE isn't the template itself, it will not have a valid
23719 TYPE_FIELDS list. */
23721 /* scope is either the template itself or a compatible instantiation
23722 like X<T>, so look up the name in the original template. */
23724 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
23726 /* If scope has no fields, it can't be a current instantiation. Check this
23727 before currently_open_class to avoid infinite recursion (71515). */
23730 /* If the SCOPE is not the current instantiation, there's no reason
23731 to look inside it. */
23734 /* Enter the SCOPE so that name lookup will be resolved as if we
23735 were in the class definition. In particular, SCOPE will no
23736 longer be considered a dependent type. */
23738 /* Look up the declaration. */
23740 tf_warning_or_error);
23744 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
23745 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
23750 {
23754 }
23757 {
23758 tree tmpl;
23759 tree args;
23760 /* Obtain the template and the arguments. */
23763 /* Instantiate the template. */
23769 }
23771 /* Leave the SCOPE. */
23775 /* If we failed to resolve it, return the original typename. */
23779 /* If lookup found a typename type, resolve that too. */
23781 {
23782 /* Ill-formed programs can cause infinite recursion here, so we
23783 must catch that. */
23787 }
23789 /* Qualify the resulting type. */
23795 }
23797 /* EXPR is an expression which is not type-dependent. Return a proxy
23798 for EXPR that can be used to compute the types of larger
23799 expressions containing EXPR. */
23801 tree
23803 {
23804 tree inner_expr;
23806 /* When checking, try to get a constant value for all non-dependent
23807 expressions in order to expose bugs in *_dependent_expression_p
23808 and constexpr. This can affect code generation, see PR70704, so
23809 only do this for -fchecking=2. */
23812 /* Don't do this during nsdmi parsing as it can lead to
23813 unexpected recursive instantiations. */
23815 /* Don't do this during concept expansion either and for
23816 the same reason. */
23820 /* Preserve OVERLOADs; the functions must be available to resolve
23821 types. */
23832 /* There is no need to return a proxy for a variable. */
23835 /* Preserve string constants; conversions from string constants to
23836 "char *" are allowed, even though normally a "const char *"
23837 cannot be used to initialize a "char *". */
23840 /* Preserve void and arithmetic constants, as an optimization -- there is no
23841 reason to create a new node. */
23846 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
23847 There is at least one place where we want to know that a
23848 particular expression is a throw-expression: when checking a ?:
23849 expression, there are special rules if the second or third
23850 argument is a throw-expression. */
23854 /* Don't wrap an initializer list, we need to be able to look inside. */
23858 /* Don't wrap a dummy object, we need to be able to test for it. */
23877 /* If the type is unknown, it can't really be non-dependent */
23880 /* Otherwise, build a NON_DEPENDENT_EXPR. */
23882 }
23884 /* ARGS is a vector of expressions as arguments to a function call.
23885 Replace the arguments with equivalent non-dependent expressions.
23886 This modifies ARGS in place. */
23888 void
23890 {
23892 tree arg;
23895 {
23899 }
23900 }
23902 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
23903 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
23904 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
23906 static tree
23908 {
23922 }
23924 tree
23926 {
23928 }
23930 tree
23932 {
23934 }
23936 /* Make a "constrained auto" type-specifier. This is an
23937 auto type with constraints that must be associated after
23938 deduction. The constraint is formed from the given
23939 CONC and its optional sequence of arguments, which are
23940 non-null if written as partial-concept-id. */
23942 tree
23944 {
23947 /* Build the constraint. */
23949 tree expr;
23952 else
23958 /* Our canonical type depends on the constraint. */
23961 /* Attach the constraint to the type declaration. */
23964 }
23966 /* Given type ARG, return std::initializer_list<ARG>. */
23968 static tree
23970 {
23971 tree std_init_list = namespace_binding
23973 tree argvec;
23975 {
23979 }
23984 }
23986 /* Replace auto in TYPE with std::initializer_list<auto>. */
23988 static tree
23990 {
23997 }
23999 /* Hash traits for hashing possibly constrained 'auto'
24000 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24003 {
24006 };
24008 /* Hash the 'auto' T. */
24010 inline hashval_t
24012 {
24014 /* Matching constrained-type-specifiers denote the same template
24015 parameter, so hash the constraint. */
24017 else
24018 /* But unconstrained autos are all separate, so just hash the pointer. */
24020 }
24022 /* Compare two 'auto's. */
24026 {
24033 /* Two unconstrained autos are distinct. */
24038 }
24040 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24041 constrained) auto, add it to the vector. */
24043 static int
24045 {
24048 {
24049 /* All the autos were built with index 0; fix that up now. */
24053 /* If this is a repeated constrained-type-specifier, use the index we
24054 chose before. */
24056 else
24057 {
24058 /* Otherwise this is new, so use the current count. */
24061 }
24063 }
24065 /* Always keep walking. */
24067 }
24069 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24070 says they can appear anywhere in the type. */
24072 static tree
24074 {
24083 {
24088 }
24091 }
24093 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24094 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
24096 tree
24098 {
24100 tf_warning_or_error,
24101 adc_unspecified);
24102 }
24104 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24105 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
24106 The CONTEXT determines the context in which auto deduction is performed
24107 and is used to control error diagnostics.
24109 For partial-concept-ids, extra args may be appended to the list of deduced
24110 template arguments prior to determining constraint satisfaction. */
24112 tree
24115 {
24116 tree targs;
24122 /* Defining a subset of type-dependent expressions that we can deduce
24123 from ahead of time isn't worth the trouble. */
24126 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
24127 with either a new invented type template parameter U or, if the
24128 initializer is a braced-init-list (8.5.4), with
24129 std::initializer_list<U>. */
24131 {
24136 else
24137 {
24139 {
24143 "for deduction to %<std::initializer_list%>, use copy-"
24145 }
24147 }
24148 }
24156 {
24165 {
24169 }
24170 }
24171 else
24172 {
24174 tree tparms;
24178 else
24179 {
24183 }
24190 {
24192 /* Try again at instantiation time. */
24196 /* If type is error_mark_node a diagnostic must have been
24197 emitted by now. Also, having a mention to '<type error>'
24198 in the diagnostic is not really useful to the user. */
24199 {
24203 else
24208 }
24210 }
24211 }
24213 /* Check any placeholder constraints against the deduced type. */
24216 {
24217 /* Use the deduced type to check the associated constraints. If we
24218 have a partial-concept-id, rebuild the argument list so that
24219 we check using the extra arguments. */
24223 {
24226 }
24227 else
24230 {
24232 {
24234 {
24250 }
24252 }
24254 }
24255 }
24260 }
24262 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
24263 result. */
24265 tree
24267 {
24269 {
24275 /* In an abbreviated function template we didn't know we were dealing
24276 with a function template when we saw the auto return type, so update
24277 it to have the correct level. */
24279 }
24281 }
24283 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
24284 'decltype(auto)'. */
24286 bool
24288 {
24293 else
24295 }
24297 /* for_each_template_parm callback for type_uses_auto. */
24299 int
24301 {
24303 }
24305 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
24306 a use of `auto'. Returns NULL_TREE otherwise. */
24308 tree
24310 {
24314 {
24315 /* The Concepts TS allows multiple autos in one type-specifier; just
24316 return the first one we find, do_auto_deduction will collect all of
24317 them. */
24321 else
24323 }
24324 else
24326 }
24328 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
24329 'decltype(auto)' or a concept. */
24331 bool
24333 {
24335 }
24337 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
24338 a concept identifier) iff TYPE contains a use of a generic type. Returns
24339 NULL_TREE otherwise. */
24341 tree
24343 {
24345 }
24348 /* For a given template T, return the vector of typedefs referenced
24349 in T for which access check is needed at T instantiation time.
24350 T is either a FUNCTION_DECL or a RECORD_TYPE.
24351 Those typedefs were added to T by the function
24352 append_type_to_template_for_access_check. */
24356 {
24357 tree ti;
24368 {
24373 }
24376 }
24378 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
24379 tied to T. That list of typedefs will be access checked at
24380 T instantiation time.
24381 T is either a FUNCTION_DECL or a RECORD_TYPE.
24382 TYPE_DECL is a TYPE_DECL node representing a typedef.
24383 SCOPE is the scope through which TYPE_DECL is accessed.
24384 LOCATION is the location of the usage point of TYPE_DECL.
24386 This function is a subroutine of
24387 append_type_to_template_for_access_check. */
24389 static void
24391 tree type_decl,
24392 tree scope,
24393 location_t location)
24394 {
24395 qualified_typedef_usage_t typedef_usage;
24396 tree ti;
24403 && type_decl
24417 }
24419 /* Append TYPE_DECL to the template TEMPL.
24420 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
24421 At TEMPL instanciation time, TYPE_DECL will be checked to see
24422 if it can be accessed through SCOPE.
24423 LOCATION is the location of the usage point of TYPE_DECL.
24425 e.g. consider the following code snippet:
24427 class C
24428 {
24429 typedef int myint;
24430 };
24432 template<class U> struct S
24433 {
24434 C::myint mi; // <-- usage point of the typedef C::myint
24435 };
24437 S<char> s;
24439 At S<char> instantiation time, we need to check the access of C::myint
24440 In other words, we need to check the access of the myint typedef through
24441 the C scope. For that purpose, this function will add the myint typedef
24442 and the scope C through which its being accessed to a list of typedefs
24443 tied to the template S. That list will be walked at template instantiation
24444 time and access check performed on each typedefs it contains.
24445 Note that this particular code snippet should yield an error because
24446 myint is private to C. */
24448 void
24450 tree type_decl,
24451 tree scope,
24452 location_t location)
24453 {
24459 /* Make sure we don't append the type to the template twice. */
24466 }
24468 /* Convert the generic type parameters in PARM that match the types given in the
24469 range [START_IDX, END_IDX) from the current_template_parms into generic type
24470 packs. */
24472 tree
24474 {
24485 {
24486 /* Create a distinct parameter pack type from the current parm and add it
24487 to the replacement args to tsubst below into the generic function
24488 parameter. */
24503 }
24509 /* If there are more levels then build up the replacement with the outer
24510 template parms. */
24514 replacement);
24517 }
24519 /* Entries in the decl_constraint hash table. */
24521 {
24522 tree decl;
24523 tree ci;
24524 };
24526 /* Hashing function and equality for constraint entries. */
24528 {
24530 {
24532 }
24535 {
24537 }
24538 };
24540 /* A mapping from declarations to constraint information. Note that
24541 both templates and their underlying declarations are mapped to the
24542 same constraint information.
24544 FIXME: This is defined in pt.c because garbage collection
24545 code is not being generated for constraint.cc. */
24549 /* Returns the template constraints of declaration T. If T is not
24550 constrained, return NULL_TREE. Note that T must be non-null. */
24552 tree
24554 {
24565 else
24567 }
24569 /* Associate the given constraint information CI with the declaration
24570 T. If T is a template, then the constraints are associated with
24571 its underlying declaration. Don't build associations if CI is
24572 NULL_TREE. */
24574 void
24576 {
24588 }
24590 /* Remove the associated constraints of the declaration T. */
24592 void
24594 {
24603 }
24605 /* Memoized satisfaction results for declarations. This
24606 maps the pair (constraint_info, arguments) to the result computed
24607 by constraints_satisfied_p. */
24610 {
24611 tree ci;
24612 tree args;
24613 tree result;
24614 };
24616 /* Hashing function and equality for constraint entries. */
24619 {
24621 {
24624 }
24627 {
24629 }
24630 };
24632 /* Memoized satisfaction results for concept checks. */
24635 {
24636 tree tmpl;
24637 tree args;
24638 tree result;
24639 };
24641 /* Hashing function and equality for constraint entries. */
24644 {
24646 {
24648 }
24651 {
24656 }
24657 };
24662 /* Search for a memoized satisfaction result. Returns one of the
24663 truth value nodes if previously memoized, or NULL_TREE otherwise. */
24665 tree
24667 {
24672 else
24674 }
24676 /* Memoize the result of a satisfication test. Returns the saved result. */
24678 tree
24680 {
24687 }
24689 /* Search for a memoized satisfaction result for a concept. */
24691 tree
24693 {
24698 else
24700 }
24702 /* Memoize the result of a concept check. Returns the saved result. */
24704 tree
24706 {
24713 }
24717 /* Returns a prior concept specialization. This returns the substituted
24718 and normalized constraints defined by the concept. */
24720 tree
24722 {
24727 else
24729 }
24731 /* Save a concept expansion for later. */
24733 tree
24735 {
24742 }
24744 static hashval_t
24746 {
24755 }
24757 /* Compare the constraints of two subsumption entries. The LEFT1 and
24758 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
24759 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
24761 static bool
24763 {
24771 }
24773 /* Key/value pair for learning and memoizing subsumption results. This
24774 associates a pair of check constraints (including arguments) with
24775 a boolean value indicating the result. */
24778 {
24779 tree t1;
24780 tree t2;
24782 };
24784 /* Hashing function and equality for constraint entries. */
24787 {
24789 {
24791 }
24794 {
24799 }
24800 };
24804 /* Search for a previously cached subsumption result. */
24808 {
24813 else
24815 }
24817 /* Save a subsumption result. */
24819 bool
24821 {
24828 }
24830 /* Set up the hash table for constraint association. */
24832 void
24834 {
24843 }
24845 /* Set up the hash tables for template instantiations. */
24847 void
24849 {
24852 }
24854 /* Print stats about the template hash tables for -fstats. */
24856 void
24858 {
24867 }