| blob | 38e3a1672c1946b0d6e1211fd90c006201a0962a |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2022 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".
27 Fixed by: C++20 modules. */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a list of templates whose instantiations
55 have been deferred, either because their definitions were not yet
56 available, or because we were putting off doing the work. */
58 {
61 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 // -------------------------------------------------------------------------- //
81 // Local Specialization Stack
82 //
83 // Implementation of the RAII helper for creating new local
84 // specializations.
87 {
89 ;
92 else
94 }
97 {
99 {
102 }
103 }
105 /* True if we've recursed into fn_type_unification too many times. */
109 {
113 };
115 /* The general template is not in these tables. */
120 /* Contains canonical template parameter types. The vector is indexed by
121 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
122 TREE_LIST, whose TREE_VALUEs contain the canonical template
123 parameters of various types and levels. */
126 #define UNIFY_ALLOW_NONE 0
127 #define UNIFY_ALLOW_MORE_CV_QUAL 1
128 #define UNIFY_ALLOW_LESS_CV_QUAL 2
129 #define UNIFY_ALLOW_DERIVED 4
130 #define UNIFY_ALLOW_INTEGER 8
131 #define UNIFY_ALLOW_OUTER_LEVEL 16
132 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
133 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
136 tbr_incomplete_type,
137 tbr_ambiguous_baseclass,
138 tbr_success
139 };
223 /* Make the current scope suitable for access checking when we are
224 processing T. T can be FUNCTION_DECL for instantiated function
225 template, VAR_DECL for static member variable, or TYPE_DECL for
226 for a class or alias template (needed by instantiate_decl). */
228 void
230 {
242 /* An artificial deduction guide should have the same access as
243 the constructor. */
245 else
249 {
252 }
253 }
255 /* Restore the scope set up by push_access_scope. T is the node we
256 are processing. */
258 void
260 {
270 else
272 }
274 /* Do any processing required when DECL (a member template
275 declaration) is finished. Returns the TEMPLATE_DECL corresponding
276 to DECL, unless it is a specialization, in which case the DECL
277 itself is returned. */
279 tree
281 {
288 {
289 tree type;
297 {
301 }
303 }
308 {
310 {
313 }
314 else
316 }
317 else
322 }
324 /* Create a template info node. */
326 tree
328 {
333 }
335 /* Return the template info node corresponding to T, whatever T is. */
337 tree
339 {
361 }
363 /* Returns the template nesting level of the indicated class TYPE.
365 For example, in:
366 template <class T>
367 struct A
368 {
369 template <class U>
370 struct B {};
371 };
373 A<T>::B<U> has depth two, while A<T> has depth one.
374 Both A<T>::B<int> and A<int>::B<U> have depth one, if
375 they are instantiations, not specializations.
377 This function is guaranteed to return 0 if passed NULL_TREE so
378 that, for example, `template_class_depth (current_class_type)' is
379 always safe. */
381 int
383 {
387 {
397 {
400 else
402 }
405 else
407 }
410 }
412 /* Return TRUE if NODE instantiates a template that has arguments of
413 its own, be it directly a primary template or indirectly through a
414 partial specializations. */
415 static bool
417 {
429 /* So now we know we have a specialization, but it could be a full
430 or a partial specialization. To tell which, compare the depth of
431 its template arguments with those of its context. */
440 }
442 /* Subroutine of maybe_begin_member_template_processing.
443 Returns true if processing DECL needs us to push template parms. */
445 static bool
447 {
453 }
455 /* Subroutine of maybe_begin_member_template_processing.
456 Push the template parms in PARMS, starting from LEVELS steps into the
457 chain, and ending at the beginning, since template parms are listed
458 innermost first. */
460 static void
462 {
470 current_template_parms
476 NULL);
478 {
487 {
494 /* Push the CONST_DECL. */
500 }
501 }
502 }
504 /* Restore the template parameter context for a member template, a
505 friend template defined in a class definition, or a non-template
506 member of template class. */
508 void
510 {
511 tree parms;
516 {
519 /* Disregard full specializations (c++/60999). */
522 }
525 {
530 {
533 }
536 }
538 /* Remember how many levels of template parameters we pushed so that
539 we can pop them later. */
541 }
543 /* Undo the effects of maybe_begin_member_template_processing. */
545 void
547 {
556 {
560 }
561 }
563 /* Return a new template argument vector which contains all of ARGS,
564 but has as its innermost set of arguments the EXTRA_ARGS. */
566 tree
568 {
569 tree new_args;
587 }
589 /* Like add_to_template_args, but only the outermost ARGS are added to
590 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
591 (EXTRA_ARGS) levels are added. This function is used to combine
592 the template arguments from a partial instantiation with the
593 template arguments used to attain the full instantiation from the
594 partial instantiation.
596 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
598 tree
600 {
601 tree new_args;
606 {
609 }
611 /* If there are more levels of EXTRA_ARGS than there are ARGS,
612 something very fishy is going on. */
615 /* If *all* the new arguments will be the EXTRA_ARGS, just return
616 them. */
620 /* For the moment, we make ARGS look like it contains fewer levels. */
625 /* Now, we restore ARGS to its full dimensions. */
629 }
631 /* Return the N levels of innermost template arguments from the ARGS. */
633 tree
635 {
636 tree new_args;
642 /* If N is 1, just return the innermost set of template arguments. */
646 /* If we're not removing anything, just return the arguments we were
647 given. */
653 /* Make a new set of arguments, not containing the outer arguments. */
660 }
662 /* The inverse of get_innermost_template_args: Return all but the innermost
663 EXTRA_LEVELS levels of template arguments from the ARGS. */
665 static tree
667 {
668 tree new_args;
674 /* If N is 1, just return the outermost set of template arguments. */
678 /* If we're not removing anything, just return the arguments we were
679 given. */
684 /* Make a new set of arguments, not containing the inner arguments. */
691 }
693 /* We've got a template header coming up; push to a new level for storing
694 the parms. */
696 void
698 {
699 /* We use a non-tag-transparent scope here, which causes pushtag to
700 put tags in this scope, rather than in the enclosing class or
701 namespace scope. This is the right thing, since we want
702 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
703 global template class, push_template_decl handles putting the
704 TEMPLATE_DECL into top-level scope. For a nested template class,
705 e.g.:
707 template <class T> struct S1 {
708 template <class T> struct S2 {};
709 };
711 pushtag contains special code to insert the TEMPLATE_DECL for S2
712 at the right scope. */
718 /* Add a dummy parameter level while we process the parameter list. */
719 current_template_parms
722 current_template_parms);
723 }
725 /* This routine is called when a specialization is declared. If it is
726 invalid to declare a specialization here, an error is reported and
727 false is returned, otherwise this routine will return true. */
729 static bool
731 {
734 /* [temp.expl.spec]
736 An explicit specialization shall be declared in the namespace of
737 which the template is a member, or, for member templates, in the
738 namespace of which the enclosing class or enclosing class
739 template is a member. An explicit specialization of a member
740 function, member class or static data member of a class template
741 shall be declared in the namespace of which the class template
742 is a member. */
744 {
747 }
749 /* [temp.expl.spec]
751 In an explicit specialization declaration for a member of a class
752 template or a member template that appears in namespace scope,
753 the member template and some of its enclosing class templates may
754 remain unspecialized, except that the declaration shall not
755 explicitly specialize a class member template if its enclosing
756 class templates are not explicitly specialized as well. */
758 {
761 }
764 }
766 /* We've just seen template <>. */
768 bool
770 {
774 }
776 /* Called at then end of processing a declaration preceded by
777 template<>. */
779 void
781 {
784 }
786 /* Any template <>'s that we have seen thus far are not referring to a
787 function specialization. */
789 void
791 {
794 }
796 /* We've just seen a template header. If SPECIALIZATION is nonzero,
797 it was of the form template <>. */
799 static void
801 {
803 template_header_count++;
804 }
806 /* We're beginning an explicit instantiation. */
808 void
810 {
813 }
816 void
818 {
821 }
823 /* An explicit specialization or partial specialization of TMPL is being
824 declared. Check that the namespace in which the specialization is
825 occurring is permissible. Returns false iff it is invalid to
826 specialize TMPL in the current namespace. */
828 static bool
830 {
833 /* [tmpl.expl.spec]
835 An explicit specialization shall be declared in a namespace enclosing the
836 specialized template. An explicit specialization whose declarator-id is
837 not qualified shall be declared in the nearest enclosing namespace of the
838 template, or, if the namespace is inline (7.3.1), any namespace from its
839 enclosing namespace set. */
842 {
845 }
848 /* Same or enclosing namespace. */
850 else
851 {
852 auto_diagnostic_group d;
858 }
859 }
861 /* SPEC is an explicit instantiation. Check that it is valid to
862 perform this explicit instantiation in the current namespace. */
864 static void
866 {
867 tree ns;
869 /* DR 275: An explicit instantiation shall appear in an enclosing
870 namespace of its template. */
876 }
878 /* Returns true if TYPE is a new partial specialization that needs to be
879 set up. This may also modify TYPE to point to the correct (new or
880 existing) constrained partial specialization. */
882 static bool
884 {
885 /* An implicit instantiation of an incomplete type implies
886 the definition of a new class template.
888 template<typename T>
889 struct S;
891 template<typename T>
892 struct S<T*>;
894 Here, S<T*> is an implicit instantiation of S whose type
895 is incomplete. */
899 /* It can also be the case that TYPE is a completed specialization.
900 Continuing the previous example, suppose we also declare:
902 template<typename T>
903 requires Integral<T>
904 struct S<T*>;
906 Here, S<T*> refers to the specialization S<T*> defined
907 above. However, we need to differentiate definitions because
908 we intend to define a new partial specialization. In this case,
909 we rely on the fact that the constraints are different for
910 this declaration than that above.
912 Note that we also get here for injected class names and
913 late-parsed template definitions. We must ensure that we
914 do not create new type declarations for those cases. */
916 {
920 /* If there are no template parameters, this cannot be a new
921 partial template specialization? */
925 /* The injected-class-name is not a new partial specialization. */
929 /* If the constraints are not the same as those of the primary
930 then, we can probably create a new specialization. */
934 {
938 }
940 /* Also, if there's a pre-existing specialization with matching
941 constraints, then this also isn't new. */
944 {
950 {
953 }
955 }
957 /* Create a new type node (and corresponding type decl)
958 for the newly declared specialization. */
963 /* We only need a separate type node for storing the definition of this
964 partial specialization; uses of S<T*> are unconstrained, so all are
965 equivalent. So keep TYPE_CANONICAL the same. */
968 /* Build the corresponding type decl. */
980 }
983 }
985 /* The TYPE is being declared. If it is a template type, that means it
986 is a partial specialization. Do appropriate error-checking. */
988 tree
990 {
991 tree context;
996 /* A lambda that appears in specialization context is not itself a
997 specialization. */
1001 /* An injected-class-name is not a specialization. */
1006 {
1010 }
1015 {
1021 else
1024 }
1026 {
1027 /* This is for ordinary explicit specialization and partial
1028 specialization of a template class such as:
1030 template <> class C<int>;
1032 or:
1034 template <class T> class C<T*>;
1036 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1039 {
1046 {
1051 }
1052 }
1058 /* Trying to define a specialization either without a template<> header
1059 or in an inappropriate place. We've already given an error, so just
1060 bail now so we don't actually define the specialization. */
1062 }
1068 {
1069 /* This is for an explicit specialization of member class
1070 template according to [temp.expl.spec/18]:
1072 template <> template <class U> class C<int>::D;
1074 The context `C<int>' must be an implicit instantiation.
1075 Otherwise this is just a member class template declared
1076 earlier like:
1078 template <> class C<int> { template <class U> class D; };
1079 template <> template <class U> class C<int>::D;
1081 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1082 while in the second case, `C<int>::D' is a primary template
1083 and `C<T>::D' may not exist. */
1087 {
1088 tree t;
1093 {
1096 type))
1099 }
1101 /* Check for invalid specialization after instantiation:
1103 template <> template <> class C<int>::D<int>;
1104 template <> template <class U> class C<int>::D; */
1108 {
1112 {
1113 /* We already have a full specialization of this partial
1114 instantiation, or a full specialization has been
1115 looked up but not instantiated. Reassign it to the
1116 new member specialization template. */
1117 spec_entry elt;
1130 spec_entry **slot
1135 }
1136 else
1137 /* But if we've had an implicit instantiation, that's a
1138 problem ([temp.expl.spec]/6). */
1141 }
1143 /* Mark TYPE as a specialization. And as a result, we only
1144 have one level of template argument for the innermost
1145 class template. */
1150 }
1151 }
1153 {
1154 /* Someday C++0x may allow for enum template specialization. */
1159 else
1160 {
1163 }
1164 }
1167 }
1169 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1170 gone through coerce_template_parms by now. */
1172 static void
1174 {
1176 {
1185 /* Allow typedefs on the type of a non-type argument, since a
1187 else
1189 }
1190 }
1192 static void
1194 {
1199 }
1201 /* Retrieve the specialization (in the sense of [temp.spec] - a
1202 specialization is either an instantiation or an explicit
1203 specialization) of TMPL for the given template ARGS. If there is
1204 no such specialization, return NULL_TREE. The ARGS are a vector of
1205 arguments, or a vector of vectors of arguments, in the case of
1206 templates with more than one level of parameters.
1208 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1209 then we search for a partial specialization matching ARGS. This
1210 parameter is ignored if TMPL is not a class template.
1212 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1213 result is a NONTYPE_ARGUMENT_PACK. */
1215 static tree
1217 {
1227 /* There should be as many levels of arguments as there are
1228 levels of parameters. */
1237 /* Lambda functions in templates aren't instantiated normally, but through
1238 tsubst_lambda_expr. */
1242 spec_entry elt;
1250 else
1259 }
1261 /* Like retrieve_specialization, but for local declarations. */
1263 tree
1265 {
1271 }
1273 /* Returns nonzero iff DECL is a specialization of TMPL. */
1275 int
1277 {
1278 tree t;
1281 {
1287 }
1288 else
1289 {
1298 }
1301 }
1303 /* Returns nonzero iff DECL is a specialization of friend declaration
1304 FRIEND_DECL according to [temp.friend]. */
1306 bool
1308 {
1315 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1316 of a template class, we want to check if DECL is a specialization
1317 if this. */
1321 {
1322 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1325 }
1330 /* There is nothing to do if this is not a template friend. */
1337 /* [temp.friend/6]
1338 A member of a class template may be declared to be a friend of a
1339 non-template class. In this case, the corresponding member of
1340 every specialization of the class template is a friend of the
1341 class granting friendship.
1343 For example, given a template friend declaration
1345 template <class T> friend void A<T>::f();
1347 the member function below is considered a friend
1349 template <> struct A<int> {
1350 void f();
1351 };
1353 For this type of template friend, TEMPLATE_DEPTH below will be
1354 nonzero. To determine if DECL is a friend of FRIEND, we first
1355 check if the enclosing class is a specialization of another. */
1362 {
1363 /* Next, we check the members themselves. In order to handle
1364 a few tricky cases, such as when FRIEND_DECL's are
1366 template <class T> friend void A<T>::g(T t);
1367 template <class T> template <T t> friend void A<T>::h();
1369 and DECL's are
1371 void A<int>::g(int);
1372 template <int> void A<int>::h();
1374 we need to figure out ARGS, the template arguments from
1375 the context of DECL. This is required for template substitution
1376 of `T' in the function parameter of `g' and template parameter
1377 of `h' in the above examples. Here ARGS corresponds to `int'. */
1384 {
1386 {
1389 else
1391 current_depth++;
1392 }
1394 }
1397 {
1399 tree friend_type;
1400 tree decl_type;
1401 tree friend_args_type;
1402 tree decl_args_type;
1404 /* Make sure that both DECL and FRIEND_DECL are templates or
1405 non-templates. */
1411 {
1412 /* If both are templates, check template parameter list. */
1413 tree friend_parms
1418 friend_parms))
1422 }
1423 else
1431 /* Check if return types match. */
1435 /* Check if function parameter types match, ignoring the
1436 `this' parameter. */
1445 }
1446 else
1447 {
1448 /* DECL is a TYPE_DECL */
1452 /* Make sure that both DECL and FRIEND_DECL are templates or
1453 non-templates. */
1454 is_template
1461 {
1462 tree friend_parms;
1463 /* If both are templates, check the name of the two
1464 TEMPLATE_DECL's first because is_friend didn't. */
1469 /* Now check template parameter list. */
1470 friend_parms
1473 return comp_template_parms
1475 friend_parms);
1476 }
1477 else
1480 }
1481 }
1483 }
1485 /* Register the specialization SPEC as a specialization of TMPL with
1486 the indicated ARGS. IS_FRIEND indicates whether the specialization
1487 is actually just a friend declaration. ATTRLIST is the list of
1488 attributes that the specialization is declared with or NULL when
1489 it isn't. Returns SPEC, or an equivalent prior declaration, if
1490 available.
1492 We also store instantiations of field packs in the hash table, even
1493 though they are not themselves templates, to make lookup easier. */
1495 static tree
1497 hashval_t hash)
1498 {
1499 tree fn;
1507 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1508 register it; we want the corresponding TEMPLATE_DECL instead.
1509 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1510 the more obvious `uses_template_parms (spec)' to avoid problems
1511 with default function arguments. In particular, given
1512 something like this:
1514 template <class T> void f(T t1, T t = T())
1516 the default argument expression is not substituted for in an
1517 instantiation unless and until it is actually needed. */
1520 spec_entry elt;
1531 else
1534 /* We can sometimes try to re-register a specialization that we've
1535 already got. In particular, regenerate_decl_from_template calls
1536 duplicate_decls which will update the specialization list. But,
1537 we'll still get called again here anyhow. It's more convenient
1538 to simply allow this than to try to prevent it. */
1542 {
1544 {
1547 {
1549 fn);
1551 }
1552 else
1553 {
1554 tree clone;
1555 /* This situation should occur only if the first
1556 specialization is an implicit instantiation, the
1557 second is an explicit specialization, and the
1558 implicit instantiation has not yet been used. That
1559 situation can occur if we have implicitly
1560 instantiated a member function and then specialized
1561 it later.
1563 We can also wind up here if a friend declaration that
1564 looked like an instantiation turns out to be a
1565 specialization:
1567 template <class T> void foo(T);
1568 class S { friend void foo<>(int) };
1569 template <> void foo(int);
1571 We transform the existing DECL in place so that any
1572 pointers to it become pointers to the updated
1573 declaration.
1575 If there was a definition for the template, but not
1576 for the specialization, we want this to look as if
1577 there were no definition, and vice versa. */
1581 /* The call to duplicate_decls will have applied
1582 [temp.expl.spec]:
1584 An explicit specialization of a function template
1585 is inline only if it is explicitly declared to be,
1586 and independently of whether its function template
1587 is.
1589 to the primary function; now copy the inline bits to
1590 the various clones. */
1592 {
1599 }
1603 }
1604 }
1606 {
1609 /* We've already complained in duplicate_decls. */
1613 /* Dup decl failed, but this is a new definition. Set the
1614 line number so any errors match this new
1615 definition. */
1619 }
1620 }
1624 /* A specialization must be declared in the same namespace as the
1625 template it is specializing. */
1638 /* If TMPL is a forward declaration of a template function, keep a list
1639 of all specializations in case we need to reassign them to a friend
1640 template later in tsubst_friend_function.
1642 Also keep a list of all variable template instantiations so that
1643 process_partial_specialization can check whether a later partial
1644 specialization would have used it. */
1649 }
1651 /* Restricts tree and type comparisons. */
1655 /* Returns true iff two spec_entry nodes are equivalent. */
1657 bool
1659 {
1668 /* tmpl could be a FIELD_DECL for a capture pack. */
1672 {
1673 /* Partial specializations of a variable template can be distinguished by
1674 constraints. */
1678 }
1684 }
1686 /* Returns a hash for a template TMPL and template arguments ARGS. */
1688 static hashval_t
1690 {
1693 }
1695 hashval_t
1697 {
1702 }
1704 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1705 ignoring SPEC. */
1707 hashval_t
1709 {
1711 }
1713 /* Recursively calculate a hash value for a template argument ARG, for use
1714 in the hash tables of template specializations. We must be
1715 careful to (at least) skip the same entities template_args_equal
1716 does. */
1718 hashval_t
1720 {
1725 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1736 {
1738 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1739 preserving it in a hash table, which is bad because it will change
1740 meaning when gen_elem_of_pack_expansion_instantiation changes the
1741 ARGUMENT_PACK_SELECT_INDEX. */
1775 {
1778 {
1781 }
1783 }
1787 {
1790 }
1801 val = iterative_hash_template_arg
1813 val);
1815 val);
1824 /* [temp.over.link] Two lambda-expressions are never considered
1825 equivalent.
1827 So just hash the closure type. */
1838 /* Now hash operands as usual. */
1842 {
1845 {
1849 }
1851 call_expr_arg_iterator ai;
1856 }
1860 }
1864 {
1867 {
1868 // We want an alias specialization that survived strip_typedefs
1869 // to hash differently from its TYPE_CANONICAL, to avoid hash
1870 // collisions that compare as different in template_args_equal.
1871 // These could be dependent specializations that strip_typedefs
1872 // left alone, or untouched specializations because
1873 // coerce_template_parms returns the unconverted template
1874 // arguments if it sees incomplete argument packs.
1877 }
1880 {
1882 {
1885 /* Do not recurse with TPI directly, as that is unbounded
1886 recursion. */
1889 }
1898 {
1899 /* Hash the components that are relevant to TYPENAME_TYPE
1900 equivalence as determined by structural_comptypes. We
1901 can only coherently do this when comparing_specializations
1902 is set, because otherwise structural_comptypes tries
1903 resolving TYPENAME_TYPE via the current instantiation. */
1908 }
1915 }
1928 }
1929 }
1931 /* Unregister the specialization SPEC as a specialization of TMPL.
1932 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1933 if the SPEC was listed as a specialization of TMPL.
1935 Note that SPEC has been ggc_freed, so we can't look inside it. */
1937 bool
1939 {
1941 spec_entry elt;
1949 {
1954 }
1957 }
1959 /* Like register_specialization, but for local declarations. We are
1960 registering SPEC, an instantiation of TMPL. */
1962 void
1964 {
1967 }
1969 /* Registers T as a specialization of itself. This is used to preserve
1970 the references to already-parsed parameters when instantiating
1971 postconditions. */
1973 void
1975 {
1977 }
1979 /* TYPE is a class type. Returns true if TYPE is an explicitly
1980 specialized class. */
1982 bool
1984 {
1988 }
1990 /* Print the list of functions at FNS, going through all the overloads
1991 for each element of the list. Alternatively, FNS cannot be a
1992 TREE_LIST, in which case it will be printed together with all the
1993 overloads.
1995 MORE and *STR should respectively be FALSE and NULL when the function
1996 is called from the outside. They are used internally on recursive
1997 calls. print_candidates manages the two parameters and leaves NULL
1998 in *STR when it ends. */
2000 static void
2002 {
2006 else
2008 {
2014 {
2017 else
2020 }
2022 }
2023 }
2025 /* Print the list of candidate FNS in an error message. FNS can also
2026 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2028 void
2030 {
2034 }
2036 /* Get a (possibly) constrained template declaration for the
2037 purpose of ordering candidates. */
2038 static tree
2040 {
2046 }
2048 /* Among candidates having the same signature, return the
2049 most constrained or NULL_TREE if there is no best candidate.
2050 If the signatures of candidates vary (e.g., template
2051 specialization vs. member function), then there can be no
2052 most constrained.
2054 Note that we don't compare constraints on the functions
2055 themselves, but rather those of their templates. */
2056 static tree
2058 {
2059 // Try to find the best candidate in a first pass.
2062 {
2069 }
2071 // Verify that the champ is better than previous candidates.
2076 }
2079 }
2082 /* Returns the template (one of the functions given by TEMPLATE_ID)
2083 which can be specialized to match the indicated DECL with the
2084 explicit template args given in TEMPLATE_ID. The DECL may be
2085 NULL_TREE if none is available. In that case, the functions in
2086 TEMPLATE_ID are non-members.
2088 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2089 specialization of a member template.
2091 The TEMPLATE_COUNT is the number of references to qualifying
2092 template classes that appeared in the name of the function. See
2093 check_explicit_specialization for a more accurate description.
2095 TSK indicates what kind of template declaration (if any) is being
2096 declared. TSK_TEMPLATE indicates that the declaration given by
2097 DECL, though a FUNCTION_DECL, has template parameters, and is
2098 therefore a template function.
2100 The template args (those explicitly specified and those deduced)
2101 are output in a newly created vector *TARGS_OUT.
2103 If it is impossible to determine the result, an error message is
2104 issued. The error_mark_node is returned to indicate failure. */
2106 static tree
2108 tree decl,
2112 tmpl_spec_kind tsk)
2113 {
2114 tree fns;
2115 tree targs;
2116 tree explicit_targs;
2119 /* A TREE_LIST of templates of which DECL may be a specialization.
2120 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2121 corresponding TREE_PURPOSE is the set of template arguments that,
2122 when used to instantiate the template, would produce a function
2123 with the signature of DECL. */
2133 /* We shouldn't be specializing a member template of an
2134 unspecialized class template; we already gave an error in
2135 check_specialization_scope, now avoid crashing. */
2139 {
2142 }
2150 /* Check for baselinks. */
2155 {
2159 }
2161 {
2164 }
2166 /* Count the number of template headers specified for this
2167 specialization. */
2178 {
2181 tf_warning_or_error);
2185 }
2187 {
2191 {
2192 tree decl_arg_types;
2193 tree fn_arg_types;
2195 /* In case of explicit specialization, we need to check if
2196 the number of template headers appearing in the specialization
2197 is correct. This is usually done in check_explicit_specialization,
2198 but the check done there cannot be exhaustive when specializing
2199 member functions. Consider the following code:
2201 template <> void A<int>::f(int);
2202 template <> template <> void A<int>::f(int);
2204 Assuming that A<int> is not itself an explicit specialization
2205 already, the first line specializes "f" which is a non-template
2206 member function, whilst the second line specializes "f" which
2207 is a template member function. So both lines are syntactically
2208 correct, and check_explicit_specialization does not reject
2209 them.
2211 Here, we can do better, as we are matching the specialization
2212 against the declarations. We count the number of template
2213 headers, and we check if they match TEMPLATE_COUNT + 1
2214 (TEMPLATE_COUNT is the number of qualifying template classes,
2215 plus there must be another header for the member template
2216 itself).
2218 Notice that if header_count is zero, this is not a
2219 specialization but rather a template instantiation, so there
2220 is no check we can perform here. */
2222 {
2225 }
2227 /* Check that the number of template arguments at the
2228 innermost level for DECL is the same as for FN. */
2236 /* DECL might be a specialization of FN. */
2240 /* For a non-static member function, we need to make sure
2241 that the const qualification is the same. Since
2242 get_bindings does not try to merge the "this" parameter,
2243 we must do the comparison explicitly. */
2245 {
2250 /* And the ref-qualification. */
2254 }
2256 /* Skip the "this" parameter and, for constructors of
2257 classes with virtual bases, the VTT parameter. A
2258 full specialization of a constructor will have a VTT
2259 parameter, but a template never will. */
2260 decl_arg_types
2262 fn_arg_types
2265 /* Function templates cannot be specializations; there are
2266 no partial specializations of functions. Therefore, if
2267 the type of DECL does not match FN, there is no
2268 match.
2270 Note that it should never be the case that we have both
2271 candidates added here, and for regular member functions
2272 below. */
2274 {
2276 current_template_parms))
2289 {
2290 /* C++20 CA104: Substitute directly into the
2291 constraint-expression. */
2297 }
2301 }
2303 /* See whether this function might be a specialization of this
2304 template. Suppress access control because we might be trying
2305 to make this specialization a friend, and we have already done
2306 access control for the declaration of the specialization. */
2312 /* We cannot deduce template arguments that when used to
2313 specialize TMPL will produce DECL. */
2317 /* We deduced something involving 'auto', which isn't a valid
2318 template argument. */
2321 /* Save this template, and the arguments deduced. */
2323 }
2325 /* FN is an ordinary member function, and we need a
2326 specialization of a member template. */
2327 ;
2329 /* We can get IDENTIFIER_NODEs here in certain erroneous
2330 cases. */
2331 ;
2333 /* This is just an ordinary non-member function. Nothing can
2334 be a specialization of that. */
2335 ;
2337 /* Cannot specialize functions that are created implicitly. */
2338 ;
2339 else
2340 {
2341 tree decl_arg_types;
2343 /* This is an ordinary member function. However, since
2344 we're here, we can assume its enclosing class is a
2345 template class. For example,
2347 template <typename T> struct S { void f(); };
2348 template <> void S<int>::f() {}
2350 Here, S<int>::f is a non-template, but S<int> is a
2351 template class. If FN has the same type as DECL, we
2352 might be in business. */
2355 /* Its enclosing class is an explicit specialization
2356 of a template class. This is not a candidate. */
2361 /* The return types differ. */
2364 /* Adjust the type of DECL in case FN is a static member. */
2371 decl_arg_types))
2379 // If the deduced arguments do not satisfy the constraints,
2380 // this is not a candidate.
2384 // Add the candidate.
2386 }
2387 }
2390 {
2391 /* We have:
2393 [temp.expl.spec]
2395 It is possible for a specialization with a given function
2396 signature to be instantiated from more than one function
2397 template. In such cases, explicit specification of the
2398 template arguments must be used to uniquely identify the
2399 function template specialization being specialized.
2401 Note that here, there's no suggestion that we're supposed to
2402 determine which of the candidate templates is most
2403 specialized. However, we, also have:
2405 [temp.func.order]
2407 Partial ordering of overloaded function template
2408 declarations is used in the following contexts to select
2409 the function template to which a function template
2410 specialization refers:
2412 -- when an explicit specialization refers to a function
2413 template.
2415 So, we do use the partial ordering rules, at least for now.
2416 This extension can only serve to make invalid programs valid,
2417 so it's safe. And, there is strong anecdotal evidence that
2418 the committee intended the partial ordering rules to apply;
2419 the EDG front end has that behavior, and John Spicer claims
2420 that the committee simply forgot to delete the wording in
2421 [temp.expl.spec]. */
2424 {
2427 }
2428 }
2430 // Concepts allows multiple declarations of member functions
2431 // with the same signature. Like above, we need to rely on
2432 // on the partial ordering of those candidates to determine which
2433 // is the best.
2435 {
2437 {
2440 }
2441 }
2444 {
2449 "saw %d %<template<>%>, need %d for "
2454 }
2458 {
2464 }
2466 /* We have one, and exactly one, match. */
2468 {
2472 /* Propagate the candidate's constraints to the declaration. */
2476 /* DECL is a re-declaration or partial instantiation of a template
2477 function. */
2480 /* It was a specialization of an ordinary member function in a
2481 template class. */
2483 }
2485 /* It was a specialization of a template. */
2489 /* Propagate the template's constraints to the declaration. */
2494 }
2496 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2497 but with the default argument values filled in from those in the
2498 TMPL_TYPES. */
2500 static tree
2502 tree tmpl_types)
2503 {
2504 tree new_spec_types;
2512 /* Substitute into the rest of the list. */
2513 new_spec_types =
2517 /* Add the default argument for this parameter. */
2520 new_spec_types);
2521 }
2523 /* DECL is an explicit specialization. Replicate default arguments
2524 from the template it specializes. (That way, code like:
2526 template <class T> void f(T = 3);
2527 template <> void f(double);
2528 void g () { f (); }
2530 works, as required.) An alternative approach would be to look up
2531 the correct default arguments at the call-site, but this approach
2532 is consistent with how implicit instantiations are handled. */
2534 static void
2536 {
2537 tree tmpl;
2538 tree spec_types;
2539 tree tmpl_types;
2540 tree new_spec_types;
2541 tree old_type;
2542 tree new_type;
2543 tree t;
2548 /* See if there's anything we need to do. */
2561 {
2562 /* Remove the this pointer, but remember the object's type for
2563 CV quals. */
2569 {
2570 /* DECL may contain more parameters than TMPL due to the extra
2571 in-charge parameter in constructors and destructors. */
2574 }
2576 {
2579 }
2580 }
2582 /* Compute the merged default arguments. */
2583 new_spec_types =
2586 /* Compute the new FUNCTION_TYPE. */
2588 {
2592 new_spec_types);
2595 /* Put the in-charge parameter back. */
2598 new_spec_types);
2602 new_spec_types);
2603 }
2604 else
2606 new_spec_types);
2612 }
2614 /* Return the number of template headers we expect to see for a definition
2615 or specialization of CTYPE or one of its non-template members. */
2617 int
2619 {
2623 {
2624 /* You're supposed to have one `template <...>' for every
2625 template class, but you don't need one for a full
2626 specialization. For example:
2628 template <class T> struct S{};
2629 template <> struct S<int> { void f(); };
2630 void S<int>::f () {}
2632 is correct; there shouldn't be a `template <>' for the
2633 definition of `S<int>::f'. */
2635 /* If CTYPE does not have template information of any
2636 kind, then it is not a template, nor is it nested
2637 within a template. */
2645 }
2648 }
2650 /* Do a simple sanity check on the template headers that precede the
2651 variable declaration DECL. */
2653 void
2655 {
2660 {
2663 "variable templates only available with "
2666 // Namespace-scope variable templates should have a template header.
2668 }
2670 {
2671 auto_diagnostic_group d;
2673 "too many template headers for %qD "
2679 "members of an explicitly specialized class are defined "
2681 }
2682 }
2684 /* An explicit specialization whose declarator-id or class-head-name is not
2685 qualified shall be declared in the nearest enclosing namespace of the
2686 template, or, if the namespace is inline (7.3.1), any namespace from its
2687 enclosing namespace set.
2689 If the name declared in the explicit instantiation is an unqualified name,
2690 the explicit instantiation shall appear in the namespace where its template
2691 is declared or, if that namespace is inline (7.3.1), any namespace from its
2692 enclosing namespace set. */
2694 void
2696 {
2701 {
2707 /* This was allowed in C++98, so only pedwarn. */
2709 "outside its namespace must use a nested-name-"
2711 }
2712 }
2714 /* Warn for a template specialization SPEC that is missing some of a set
2715 of function or type attributes that the template TEMPL is declared with.
2716 ATTRLIST is a list of additional attributes that SPEC should be taken
2717 to ultimately be declared with. */
2719 static void
2721 {
2725 /* Avoid warning if the difference between the primary and
2726 the specialization is not in one of the attributes below. */
2730 };
2732 /* Put together a list of the black listed attributes that the primary
2733 template is declared with that the specialization is not, in case
2734 it's not apparent from the most recent declaration of the primary. */
2735 pretty_printer str;
2742 auto_diagnostic_group d;
2745 spec))
2751 }
2753 /* Check to see if the function just declared, as indicated in
2754 DECLARATOR, and in DECL, is a specialization of a function
2755 template. We may also discover that the declaration is an explicit
2756 instantiation at this point.
2758 Returns DECL, or an equivalent declaration that should be used
2759 instead if all goes well. Issues an error message if something is
2760 amiss. Returns error_mark_node if the error is not easily
2761 recoverable.
2763 FLAGS is a bitmask consisting of the following flags:
2765 2: The function has a definition.
2766 4: The function is a friend.
2768 The TEMPLATE_COUNT is the number of references to qualifying
2769 template classes that appeared in the name of the function. For
2770 example, in
2772 template <class T> struct S { void f(); };
2773 void S<int>::f();
2775 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2776 classes are not counted in the TEMPLATE_COUNT, so that in
2778 template <class T> struct S {};
2779 template <> struct S<int> { void f(); }
2780 template <> void S<int>::f();
2782 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2783 invalid; there should be no template <>.)
2785 If the function is a specialization, it is marked as such via
2786 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2787 is set up correctly, and it is added to the list of specializations
2788 for that template. */
2790 tree
2792 tree decl,
2795 tree attrlist)
2796 {
2805 tmpl_spec_kind tsk;
2808 {
2811 else
2813 }
2814 else
2818 {
2821 {
2824 }
2828 {
2830 /* This could be something like:
2832 template <class T> void f(T);
2833 class S { friend void f<>(int); } */
2835 else
2836 {
2837 /* This case handles bogus declarations like template <>
2838 template <class T> void f<int>(); */
2842 declarator);
2844 }
2845 }
2849 /* The error has already been reported in
2850 check_specialization_scope. */
2856 /* Fall through. */
2869 decl);
2872 else
2876 /* Fall through. */
2882 /* In cases like template<> constexpr bool v = true;
2883 We'll give an error in check_template_variable. */
2889 else
2895 {
2896 /* This case handles bogus declarations like template <>
2897 template <class T> void f<int>(); */
2902 declarator);
2904 {
2905 /* Partial specialization of variable template. */
2909 }
2912 "non-type partial specialization %qE "
2914 else
2916 "non-class, non-variable partial specialization %qE "
2919 ok:;
2920 }
2923 /* This is a specialization of a member template, without
2924 specialization the containing class. Something like:
2926 template <class T> struct S {
2927 template <class U> void f (U);
2928 };
2929 template <> template <class U> void S<int>::f(U) {}
2931 That's a specialization -- but of the entire template. */
2937 }
2940 /* This doesn't apply to variable templates. */
2942 {
2946 {
2950 }
2951 }
2954 {
2960 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2962 {
2963 tree fns;
2968 else
2969 {
2970 /* If there is no class context, the explicit instantiation
2971 must be at namespace scope. */
2974 /* Find the namespace binding, using the declaration
2975 context. */
2979 {
2980 /* If lookup fails, look for a friend declaration so we can
2981 give a better diagnostic. */
2982 fns = (lookup_qualified_name
2987 }
2990 {
2993 }
2994 }
2997 }
3003 {
3005 /* A specialization in class scope. This is invalid,
3006 but the error will already have been flagged by
3007 check_specialization_scope. */
3009 else
3010 {
3011 /* It's not valid to write an explicit instantiation in
3012 class scope, e.g.:
3014 class C { template void f(); }
3016 This case is caught by the parser. However, on
3017 something like:
3019 template class C { void f(); };
3021 (which is invalid) we can get here. The error will be
3022 issued later. */
3023 ;
3024 }
3027 }
3030 {
3031 // We'll match variable templates in start_decl.
3035 /* Find the list of functions in ctype that have the same
3036 name as the declared function. */
3040 {
3044 {
3045 /* From [temp.expl.spec]:
3047 If such an explicit specialization for the member
3048 of a class template names an implicitly-declared
3049 special member function (clause _special_), the
3050 program is ill-formed.
3052 Similar language is found in [temp.explicit]. */
3055 }
3058 }
3060 /* For a type-conversion operator, We might be looking for
3061 `operator int' which will be a specialization of
3062 `operator T'. Grab all the conversion operators, and
3063 then select from them. */
3068 {
3071 }
3072 else
3074 }
3076 /* Figure out what exactly is being specialized at this point.
3077 Note that for an explicit instantiation, even one for a
3078 member function, we cannot tell a priori whether the
3079 instantiation is for a member template, or just a member
3080 function of a template class. Even if a member template is
3081 being instantiated, the member template arguments may be
3082 elided if they can be deduced from the rest of the
3083 declaration. */
3086 member_specialization,
3087 template_count,
3088 tsk);
3091 /* We couldn't figure out what this declaration was
3092 specializing. */
3094 else
3095 {
3097 {
3098 auto_diagnostic_group d;
3100 "friend declaration %qD is not visible to "
3104 }
3113 {
3114 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3115 is done by do_decl_instantiation later. */
3121 {
3122 /* If TMPL is not the most general template (for
3123 example, if TMPL is a friend template that is
3124 injected into namespace scope), then there will
3125 be too many levels of TARGS. Remove some of them
3126 here. */
3128 tree new_targs;
3135 }
3138 }
3140 /* If we thought that the DECL was a member function, but it
3141 turns out to be specializing a static member function,
3142 make DECL a static member function as well. */
3148 /* If this is a specialization of a member template of a
3149 template class, we want to return the TEMPLATE_DECL, not
3150 the specialization of it. */
3152 {
3157 {
3158 tree parm;
3162 /* We want to use the argument list specified in the
3163 definition, not in the original declaration. */
3168 }
3173 }
3175 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3181 /* Inherit default function arguments from the template
3182 DECL is specializing. */
3186 /* This specialization has the same protection as the
3187 template it specializes. */
3191 /* 7.1.1-1 [dcl.stc]
3193 A storage-class-specifier shall not be specified in an
3194 explicit specialization...
3196 The parser rejects these, so unless action is taken here,
3197 explicit function specializations will always appear with
3198 global linkage.
3200 The action recommended by the C++ CWG in response to C++
3201 defect report 605 is to make the storage class and linkage
3202 of the explicit specialization match the templated function:
3204 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3205 */
3207 {
3211 /* A concept cannot be specialized. */
3213 {
3215 gen_tmpl);
3217 }
3219 /* This specialization has the same linkage and visibility as
3220 the function template it specializes. */
3223 {
3226 }
3229 {
3232 }
3233 }
3235 /* If DECL is a friend declaration, declared using an
3236 unqualified name, the namespace associated with DECL may
3237 have been set incorrectly. For example, in:
3239 template <typename T> void f(T);
3240 namespace N {
3241 struct S { friend void f<int>(int); }
3242 }
3244 we will have set the DECL_CONTEXT for the friend
3245 declaration to N, rather than to the global namespace. */
3250 /* This is not really a declaration of a specialization.
3251 It's just the name of an instantiation. But, it's not
3252 a request for an instantiation, either. */
3255 /* A specialization is not necessarily COMDAT. */
3261 /* If this is a full specialization, register it so that we can find
3262 it again. Partial specializations will be registered in
3263 process_partial_specialization. */
3265 {
3270 }
3272 /* If this is a specialization, splice any contracts that may have
3273 been inherited from the template, removing them. */
3277 /* A 'structor should already have clones. */
3283 }
3284 }
3287 }
3289 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3290 parameters. These are represented in the same format used for
3291 DECL_TEMPLATE_PARMS. */
3293 int
3295 {
3296 const_tree p1;
3297 const_tree p2;
3305 {
3317 {
3321 /* If either of the template parameters are invalid, assume
3322 they match for the sake of error recovery. */
3335 }
3336 }
3339 /* One set of parameters has more parameters lists than the
3340 other. */
3344 }
3346 /* Returns true if two template parameters are declared with
3347 equivalent constraints. */
3349 static bool
3351 {
3359 }
3361 /* Returns true when two template parameters are equivalent. */
3363 static bool
3365 {
3369 /* If either of the template parameters are invalid, assume
3370 they match for the sake of error recovery. */
3374 /* ... they declare parameters of the same kind. */
3378 /* ... one parameter was introduced by a parameter declaration, then
3379 both are. This case arises as a result of eagerly rewriting declarations
3380 during parsing. */
3384 /* ... if either declares a pack, they both do. */
3389 {
3390 /* ... if they declare non-type parameters, the types are equivalent. */
3393 }
3395 {
3396 /* ... if they declare template template parameters, their template
3397 parameter lists are equivalent. */
3400 }
3402 /* ... if they are declared with a qualified-concept name, they both
3403 are, and those names are equivalent. */
3405 }
3407 /* Returns true if two template parameters lists are equivalent.
3408 Two template parameter lists are equivalent if they have the
3409 same length and their corresponding parameters are equivalent.
3411 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3412 data structure returned by DECL_TEMPLATE_PARMS.
3414 This is generally the same implementation as comp_template_parms
3415 except that it also the concept names and arguments used to
3416 introduce parameters. */
3418 static bool
3420 {
3427 {
3435 {
3440 }
3444 }
3450 }
3452 /* Return true if the requires-clause of the template parameter lists are
3453 equivalent and false otherwise. */
3454 static bool
3456 {
3464 }
3466 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3467 Two template heads are equivalent if their template parameter
3468 lists are equivalent and their requires clauses are equivalent.
3470 In pre-C++20, this is equivalent to calling comp_template_parms
3471 for the template parameters of TMPL1 and TMPL2. */
3473 bool
3475 {
3479 /* Don't change the matching rules for pre-C++20. */
3483 /* ... have the same number of template parameters, and their
3484 corresponding parameters are equivalent. */
3488 /* ... if either has a requires-clause, they both do and their
3489 corresponding constraint-expressions are equivalent. */
3491 }
3493 /* Determine whether PARM is a parameter pack. */
3495 bool
3497 {
3498 /* Determine if we have a non-type template parameter pack. */
3505 /* If this is a list of template parameters, we could get a
3506 TYPE_DECL or a TEMPLATE_DECL. */
3510 /* Otherwise it must be a type template parameter. */
3514 }
3516 /* Determine if T is a function parameter pack. */
3518 bool
3520 {
3524 }
3526 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3527 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3529 tree
3531 {
3538 }
3540 /* Return true iff the function parameter PARAM_DECL was expanded
3541 from the function parameter pack PACK. */
3543 bool
3545 {
3550 /* The parameter pack and its pack arguments have the same
3551 DECL_PARM_INDEX. */
3553 }
3555 /* Determine whether ARGS describes a variadic template args list,
3556 i.e., one that is terminated by a template argument pack. */
3558 static bool
3560 {
3562 tree last_parm;
3576 }
3578 /* Generate a new name for the parameter pack name NAME (an
3579 IDENTIFIER_NODE) that incorporates its */
3581 static tree
3583 {
3584 /* Munge the name to include the parameter index. */
3585 #define NUMBUF_LEN 128
3599 }
3601 /* Return true if T is a primary function, class or alias template
3602 specialization, not including the template pattern. */
3604 bool
3606 {
3622 }
3624 /* Return true if PARM is a template template parameter. */
3626 bool
3628 {
3630 }
3632 /* Return true iff PARM is a DECL representing a type template
3633 parameter. */
3635 bool
3637 {
3642 }
3644 /* Return the template parameters of T if T is a
3645 primary template instantiation, NULL otherwise. */
3647 tree
3649 {
3654 parms = INNERMOST_TEMPLATE_PARMS
3658 }
3660 /* Returns the template arguments of T if T is a template instantiation,
3661 NULL otherwise. */
3663 tree
3665 {
3673 }
3675 /* Return the argument pack elements of T if T is a template argument pack,
3676 NULL otherwise. */
3678 tree
3680 {
3686 }
3688 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3689 ARGUMENT_PACK_SELECT represents. */
3691 static tree
3693 {
3697 /* If the selected argument is an expansion E, that most likely means we were
3698 called from gen_elem_of_pack_expansion_instantiation during the
3699 substituting of an argument pack (of which the Ith element is a pack
3700 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3701 In this case, the Ith element resulting from this substituting is going to
3702 be a pack expansion, which pattern is the pattern of E. Let's return the
3703 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3704 resulting pack expansion from it. */
3706 {
3707 /* Make sure we aren't throwing away arg info. */
3710 }
3713 }
3715 /* Return a modification of ARGS that's suitable for preserving inside a hash
3716 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3717 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3719 static tree
3721 {
3726 {
3728 tree r;
3735 else
3738 {
3740 {
3743 }
3745 }
3746 }
3749 }
3751 /* True iff FN is a function representing a built-in variadic parameter
3752 pack. */
3754 bool
3756 {
3766 }
3768 /* True iff CALL is a call to a function representing a built-in variadic
3769 parameter pack. */
3771 static bool
3773 {
3777 }
3779 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3781 static tree
3783 tree in_decl)
3784 {
3789 {
3791 {
3794 }
3799 }
3800 else
3801 {
3806 /* Calculate the largest value of len that won't make the size of the vec
3807 overflow an int. The compiler will exceed resource limits long before
3808 this, but it seems a decent place to diagnose. */
3812 {
3816 max);
3818 }
3826 }
3827 }
3829 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3830 CALL. */
3832 static tree
3834 tree in_decl)
3835 {
3845 }
3847 /* Return true if the tree T has the extra args mechanism for
3848 avoiding partial instantiation. */
3850 static bool
3852 {
3857 }
3859 /* Structure used to track the progress of find_parameter_packs_r. */
3860 struct find_parameter_pack_data
3861 {
3862 /* TREE_LIST that will contain all of the parameter packs found by
3863 the traversal. */
3866 /* Set of AST nodes that have been visited by the traversal. */
3869 /* True iff we're making a type pack expansion. */
3872 /* True iff we found a subtree that has the extra args mechanism. */
3874 };
3876 /* Identifies all of the argument packs that occur in a template
3877 argument and appends them to the TREE_LIST inside DATA, which is a
3878 find_parameter_pack_data structure. This is a subroutine of
3879 make_pack_expansion and uses_parameter_packs. */
3880 static tree
3882 {
3888 #define WALK_SUBTREE(NODE) \
3889 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3890 ppd, ppd->visited) \
3892 /* Don't look through typedefs; we are interested in whether a
3893 parameter pack is actually written in the expression/type we're
3894 looking at, not the target type. */
3896 {
3897 /* But do look at arguments for an alias template. */
3904 }
3906 /* Identify whether this is a parameter pack or not. */
3908 {
3916 /* FALLTHRU */
3918 /* If the placeholder appears in the decl-specifier-seq of a function
3919 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3920 is a pack expansion, the invented template parameter is a template
3921 parameter pack. */
3931 {
3932 /* We don't want to walk into the type of a PARM_DECL,
3933 because we don't want to see the type parameter pack. */
3936 }
3941 {
3942 /* We don't want to walk into the type of a variadic capture proxy,
3943 because we don't want to see the type parameter pack. */
3946 }
3948 {
3950 find_parameter_packs_r,
3953 }
3965 /* Not a parameter pack. */
3967 }
3970 {
3971 /* Add this parameter pack to the list. */
3973 }
3982 /* This switch statement will return immediately if we don't find a
3983 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3985 {
3987 /* Check the template itself. */
3993 {
3995 /* Ignore the declaration of a capture proxy for a parameter pack. */
3999 /* Since we stop at typedefs above, we need to look through them at
4000 the point of the DECL_EXPR. */
4004 }
4031 {
4032 /* Since we defer implicit capture, look in the parms and body. */
4039 }
4042 {
4043 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4044 type_pack_expansion_p to false so that any placeholders
4045 within the expression don't get marked as parameter packs. */
4053 }
4062 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4069 /* Local class, need to look through the whole definition. */
4073 else
4074 /* Enum, look at the values. */
4088 }
4090 #undef WALK_SUBTREE
4093 }
4095 /* Determines if the expression or type T uses any parameter packs. */
4096 tree
4098 {
4107 }
4109 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4110 representation a base-class initializer into a parameter pack
4111 expansion. If all goes well, the resulting node will be an
4112 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4113 respectively. */
4114 tree
4116 {
4117 tree result;
4126 {
4127 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4128 class initializer. In this case, the TREE_PURPOSE will be a
4129 _TYPE node (representing the base class expansion we're
4130 initializing) and the TREE_VALUE will be a TREE_LIST
4131 containing the initialization arguments.
4133 The resulting expansion looks somewhat different from most
4134 expansions. Rather than returning just one _EXPANSION, we
4135 return a TREE_LIST whose TREE_PURPOSE is a
4136 TYPE_PACK_EXPANSION containing the bases that will be
4137 initialized. The TREE_VALUE will be identical to the
4138 original TREE_VALUE, which is a list of arguments that will
4139 be passed to each base. We do not introduce any new pack
4140 expansion nodes into the TREE_VALUE (although it is possible
4141 that some already exist), because the TREE_PURPOSE and
4142 TREE_VALUE all need to be expanded together with the same
4143 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4144 resulting TREE_PURPOSE will mention the parameter packs in
4145 both the bases and the arguments to the bases. */
4146 tree purpose;
4147 tree value;
4150 /* Determine which parameter packs will be used by the base
4151 class expansion. */
4160 {
4163 arg);
4166 }
4169 {
4170 /* Collect the sets of parameter packs used in each of the
4171 initialization arguments. */
4173 {
4174 /* Determine which parameter packs will be expanded in this
4175 argument. */
4178 }
4179 }
4183 /* Create the pack expansion type for the base type. */
4189 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4190 they will rarely be compared to anything. */
4194 }
4199 /* Build the PACK_EXPANSION_* node. */
4200 result = for_types
4205 {
4206 /* Propagate type and const-expression information. */
4209 /* Mark this read now, since the expansion might be length 0. */
4211 }
4212 else
4213 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4214 they will rarely be compared to anything. */
4217 /* Determine which parameter packs will be expanded. */
4224 /* Make sure we found some parameter packs. */
4226 {
4228 {
4231 else
4233 }
4235 }
4240 /* If the pattern of this pack expansion contains a subtree that has
4241 the extra args mechanism for avoiding partial instantiation, then
4242 force this pack expansion to also use extra args. Otherwise
4243 partial instantiation of this pack expansion may not lower the
4244 level of some parameter packs within the pattern, which would
4245 confuse tsubst_pack_expansion later (PR101764). */
4249 }
4251 /* Checks T for any "bare" parameter packs, which have not yet been
4252 expanded, and issues an error if any are found. This operation can
4253 only be done on full expressions or types (e.g., an expression
4254 statement, "if" condition, etc.), because we could have expressions like:
4256 foo(f(g(h(args)))...)
4258 where "args" is a parameter pack. check_for_bare_parameter_packs
4259 should not be called for the subexpressions args, h(args),
4260 g(h(args)), or f(g(h(args))), because we would produce erroneous
4261 error messages.
4263 Returns TRUE and emits an error if there were bare parameter packs,
4264 returns FALSE otherwise. */
4265 bool
4267 {
4289 /* It's OK for a lambda to have an unexpanded parameter pack from the
4290 containing context, but do complain about unexpanded capture packs. */
4296 {
4297 /* We're in a lambda, but it isn't the innermost class.
4298 This should work, but currently doesn't. */
4301 }
4306 {
4312 }
4315 {
4318 {
4329 else
4334 else
4338 }
4341 }
4344 }
4346 /* Expand any parameter packs that occur in the template arguments in
4347 ARGS. */
4348 tree
4350 {
4359 /* First, determine if we need to expand anything, and the number of
4360 slots we'll need. */
4362 {
4367 {
4371 else
4373 }
4374 else
4375 {
4377 num_result_args++;
4378 }
4379 }
4381 /* If no expansion is necessary, we're done. */
4385 /* Expand arguments. */
4388 non_default_args_count =
4391 {
4394 {
4401 }
4402 else
4403 {
4406 }
4407 }
4411 }
4413 /* Checks if DECL shadows a template parameter.
4415 [temp.local]: A template-parameter shall not be redeclared within its
4416 scope (including nested scopes).
4418 Emits an error and returns TRUE if the DECL shadows a parameter,
4419 returns FALSE otherwise. */
4421 bool
4423 {
4424 tree olddecl;
4426 /* If we're not in a template, we can't possibly shadow a template
4427 parameter. */
4431 /* Figure out what we're shadowing. */
4435 /* If there's no previous binding for this name, we're not shadowing
4436 anything, let alone a template parameter. */
4440 /* If we're not shadowing a template parameter, we're done. Note
4441 that OLDDECL might be an OVERLOAD (or perhaps even an
4442 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4443 node. */
4447 /* We check for decl != olddecl to avoid bogus errors for using a
4448 name inside a class. We check TPFI to avoid duplicate errors for
4449 inline member templates. */
4455 /* Don't complain about the injected class name, as we've already
4456 complained about the class itself. */
4463 else
4468 }
4470 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4471 ORIG_LEVEL, DECL, and TYPE. */
4473 static tree
4477 tree decl,
4478 tree type)
4479 {
4490 }
4493 {
4495 {
4505 }
4508 {
4513 }
4514 };
4518 /* Find the canonical type parameter for the given template type
4519 parameter. Returns the canonical type parameter, which may be TYPE
4520 if no such parameter existed. */
4522 tree
4524 {
4532 }
4534 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4535 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4536 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4537 new one is created. */
4539 static tree
4541 tsubst_flags_t complain)
4542 {
4547 {
4552 type);
4567 /* Template template parameters need this. */
4570 {
4577 }
4579 /* Attach the TPI to the decl. */
4582 else
4584 }
4587 }
4589 /* Process information from new template parameter PARM and append it
4590 to the LIST being built. This new parameter is a non-type
4591 parameter iff IS_NON_TYPE is true. This new parameter is a
4592 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4593 is in PARM_LOC. */
4595 tree
4598 {
4604 {
4614 }
4621 {
4627 {
4628 /* [temp.param]
4630 The top-level cv-qualifiers on the template-parameter are
4631 ignored when determining its type. */
4636 && !is_parameter_pack
4637 /* If we're in a nested template parameter list, the template
4638 template parameter could be a parameter pack. */
4640 {
4641 /* This template parameter is not a parameter pack, but it
4642 should be. Complain about "bare" parameter packs. */
4645 /* Recover by calling this a parameter pack. */
4647 }
4648 }
4650 /* A template parameter is not modifiable. */
4659 current_template_depth,
4664 }
4665 else
4666 {
4667 tree t;
4671 {
4673 /* This is for distinguishing between real templates and template
4674 template parameters */
4677 /* any_template_parm_r expects to be able to get the targs of a
4678 DECL_TEMPLATE_RESULT. */
4687 }
4688 else
4689 {
4691 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4694 }
4701 current_template_depth,
4705 }
4709 /* Build requirements for the type/template parameter.
4710 This must be done after SET_DECL_TEMPLATE_PARM_P or
4711 process_template_parm could fail. */
4718 /* Build the parameter node linking the parameter declaration,
4719 its default argument (if any), and its constraints (if any). */
4725 else
4729 }
4731 /* The end of a template parameter list has been reached. Process the
4732 tree list into a parameter vector, converting each parameter into a more
4733 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4734 as PARM_DECLs. */
4736 tree
4738 {
4741 /* Pop the dummy parameter level and add the real one. We do not
4742 morph the dummy parameter in place, as it might have been
4743 captured by a (nested) template-template-parm. */
4746 current_template_parms
4751 {
4757 }
4762 }
4764 // Explicitly indicate the end of the template parameter list. We assume
4765 // that the current template parameters have been constructed and/or
4766 // managed explicitly, as when creating new template template parameters
4767 // from a shorthand constraint.
4768 void
4770 {
4772 }
4774 /* end_template_decl is called after a template declaration is seen. */
4776 void
4778 {
4784 /* This matches the pushlevel in begin_template_parm_list. */
4789 }
4791 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4792 thereof, and converts it into an argument suitable to be passed to
4793 the type substitution functions. Note that if the TREE_LIST contains
4794 an error_mark node, the returned argument is error_mark_node. */
4796 tree
4798 {
4809 {
4813 else
4815 }
4821 {
4823 {
4824 /* Turn this argument into a TYPE_ARGUMENT_PACK
4825 with a single element, which expands T. */
4834 }
4835 }
4836 else
4837 {
4839 {
4840 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4841 with a single element, which expands T. */
4851 }
4852 else
4854 }
4856 }
4858 /* If T looks like a generic template argument produced by template_parm_to_arg,
4859 return the corresponding template parameter, otherwise return NULL_TREE. */
4861 static tree
4863 {
4868 {
4873 }
4880 else
4882 }
4884 /* Given a single level of template parameters (a TREE_VEC), return it
4885 as a set of template arguments. */
4887 tree
4889 {
4899 }
4901 /* Given a set of template parameters, return them as a set of template
4902 arguments. The template parameters are represented as a TREE_VEC, in
4903 the form documented in cp-tree.h for template arguments. */
4905 tree
4907 {
4908 tree header;
4913 /* If there is only one level of template parameters, we do not
4914 create a TREE_VEC of TREE_VECs. Instead, we return a single
4915 TREE_VEC containing the arguments. */
4920 {
4925 else
4927 }
4930 }
4932 /* Within the declaration of a template, return the currently active
4933 template parameters as an argument TREE_VEC. */
4935 static tree
4937 {
4939 }
4941 /* Return the fully generic arguments for of TMPL, i.e. what
4942 current_template_args would be while parsing it. */
4944 tree
4946 {
4951 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4952 template parameter, it has no TEMPLATE_INFO; for a partial
4953 specialization, it has the arguments for the primary template, and we
4959 }
4961 /* Update the declared TYPE by doing any lookups which were thought to be
4962 dependent, but are not now that we know the SCOPE of the declarator. */
4964 tree
4966 {
4977 /* Don't bother building up the args in this case. */
4979 {
4980 /* tsubst in the args corresponding to the template parameters,
4981 including auto if present. Most things will be unchanged, but
4982 make_typename_type and tsubst_qualified_id will resolve
4983 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4986 tree pushed;
4988 {
4992 }
4997 }
5003 {
5006 else
5008 }
5010 }
5012 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5013 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5014 the new template is a member template. */
5016 static tree
5018 {
5030 /* Propagate module information from the decl. */
5034 }
5036 struct template_parm_data
5037 {
5038 /* The level of the template parameters we are currently
5039 processing. */
5042 /* The index of the specialization argument we are currently
5043 processing. */
5046 /* An array whose size is the number of template parameters. The
5047 elements are nonzero if the parameter has been used in any one
5048 of the arguments processed so far. */
5051 /* An array whose size is the number of template arguments. The
5052 elements are nonzero if the argument makes use of template
5053 parameters of this level. */
5055 };
5057 /* Subroutine of push_template_decl used to see if each template
5058 parameter in a partial specialization is used in the explicit
5059 argument list. If T is of the LEVEL given in DATA (which is
5060 treated as a template_parm_data*), then DATA->PARMS is marked
5061 appropriately. */
5063 static int
5065 {
5073 {
5076 }
5078 /* In C++17 the type of a non-type argument is a deduced context. */
5083 data,
5084 NULL,
5087 /* Return zero so that for_each_template_parm will continue the
5088 traversal of the tree; we want to mark *every* template parm. */
5090 }
5092 /* Process the partial specialization DECL. */
5094 static tree
5096 {
5103 tree inner_parms;
5104 tree inst;
5114 /* A concept cannot be specialized. */
5116 {
5119 }
5124 /* We check that each of the template parameters given in the
5125 partial specialization is used in the argument list to the
5126 specialization. For example:
5128 template <class T> struct S;
5129 template <class T> struct S<T*>;
5131 The second declaration is OK because `T*' uses the template
5132 parameter T, whereas
5134 template <class T> struct S<int>;
5136 is no good. Even trickier is:
5138 template <class T>
5139 struct S1
5140 {
5141 template <class U>
5142 struct S2;
5143 template <class U>
5144 struct S2<T>;
5145 };
5147 The S2<T> declaration is actually invalid; it is a
5148 full-specialization. Of course,
5150 template <class U>
5151 struct S2<T (*)(U)>;
5153 or some such would have been OK. */
5161 {
5166 NULL,
5168 }
5171 {
5172 /* One of the template parms was not used in a deduced context in the
5173 specialization. */
5175 {
5179 }
5183 }
5188 /* [temp.class.spec]
5190 The argument list of the specialization shall not be identical to
5191 the implicit argument list of the primary template. */
5192 tree main_args
5195 && (!flag_concepts
5197 {
5200 "any template arguments; to define the primary template, "
5202 else
5204 "template arguments and is not more constrained than "
5205 "the primary template; to define the primary template, "
5208 }
5210 /* A partial specialization that replaces multiple parameters of the
5211 primary template with a pack expansion is less specialized for those
5212 parameters. */
5214 {
5216 "primary template because it replaces multiple parameters "
5219 /* Avoid crash in process_partial_specialization. */
5221 }
5224 {
5227 /* Avoid crash below. */
5229 }
5231 /* If we aren't in a dependent class, we can actually try deduction. */
5233 /* FIXME we should be able to handle a partial specialization of a
5234 partial instantiation, but currently we can't (c++/41727). */
5237 {
5238 auto_diagnostic_group d;
5241 decl))
5243 maintmpl);
5244 }
5246 /* [temp.spec.partial]
5248 The type of a template parameter corresponding to a specialized
5249 non-type argument shall not be dependent on a parameter of the
5250 specialization.
5252 Also, we verify that pack expansions only occur at the
5253 end of the argument list. */
5256 {
5263 {
5264 /* Extract the arguments from the argument pack. We'll be
5265 iterating over these in the following loop. */
5268 }
5271 {
5273 /* Get the Jth argument in the parameter pack. */
5277 {
5278 /* Pack expansions must come at the end of the
5279 argument list. */
5282 {
5286 else
5289 }
5290 }
5293 /* We only care about the pattern. */
5299 /* This next two lines are the `argument expression is not just a
5300 simple identifier' condition and also the `specialized
5301 non-type argument' bit. */
5306 {
5307 /* Look at the corresponding template parameter,
5308 marking which template parameters its type depends
5309 upon. */
5313 {
5314 /* We haven't yet initialized TPD2. Do so now. */
5316 /* The number of parameters here is the number in the
5317 main template, which, as checked in the assertion
5318 above, is NARGS. */
5322 }
5324 /* Mark the template parameters. But this time, we're
5325 looking for the template parameters of the main
5326 template, not in the specialization. */
5333 NULL,
5337 {
5338 /* The type depended on some template parameters.
5339 If they are fully specialized in the
5340 specialization, that's OK. */
5349 "type %qT of template argument %qE depends "
5351 "type %qT of template argument %qE depends "
5353 type,
5354 arg);
5355 }
5356 }
5357 }
5358 }
5360 /* We should only get here once. */
5364 // Build the template decl.
5371 /* Give template template parms a DECL_CONTEXT of the template
5372 for which they are a parameter. */
5374 {
5378 }
5381 /* We didn't register this in check_explicit_specialization so we could
5382 wait until the constraints were set. */
5384 else
5394 {
5400 {
5408 "declaration of %qD ambiguates earlier template "
5412 "partial specialization of %qD after instantiation "
5414 }
5415 }
5418 }
5420 /* PARM is a template parameter of some form; return the corresponding
5421 TEMPLATE_PARM_INDEX. */
5423 static tree
5425 {
5438 }
5440 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5441 parameter packs used by the template parameter PARM. */
5443 static void
5445 {
5446 /* A type parm can't refer to another parm. */
5450 {
5454 }
5460 {
5464 else
5466 }
5467 }
5469 /* PARM is a template parameter pack. Return any parameter packs used in
5470 its type or the type of any of its template parameters. If there are
5471 any such packs, it will be instantiated into a fixed template parameter
5472 list by partial instantiation rather than be fully deduced. */
5474 tree
5476 {
5477 /* This can only be true in a member template. */
5480 /* This can only be true for a parameter pack. */
5483 /* A type parm can't refer to another parm. */
5497 }
5499 /* Check that a template declaration's use of default arguments and
5500 parameter packs is not invalid. Here, PARMS are the template
5501 parameters. IS_PRIMARY is true if DECL is the thing declared by
5502 a primary template. IS_PARTIAL is true if DECL is a partial
5503 specialization.
5505 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5506 function template declaration or a friend class template
5507 declaration. In the function case, 1 indicates a declaration, 2
5508 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5509 emitted for extraneous default arguments.
5511 Returns TRUE if there were no errors found, FALSE otherwise. */
5513 bool
5516 {
5519 tree parm_level;
5522 /* [temp.param]
5524 A default template-argument shall not be specified in a
5525 function template declaration or a function template definition, nor
5526 in the template-parameter-list of the definition of a member of a
5527 class template. */
5531 /* You can't have a function template declaration in a local
5532 scope, nor you can you define a member of a class template in a
5533 local scope. */
5541 /* A lambda doesn't have an explicit declaration; don't complain
5542 about the parms of the enclosing class. */
5549 /* If this is either a friend defined in the scope of the class
5550 or a member function. */
5556 /* And, if it was a member function, it really was defined in
5557 the scope of the class. */
5560 /* We already checked these parameters when the template was
5561 declared, so there's no need to do it again now. This function
5562 was defined in class scope, but we're processing its body now
5563 that the class is complete. */
5566 /* Core issue 226 (C++0x only): the following only applies to class
5567 templates. */
5570 {
5571 /* [temp.param]
5573 If a template-parameter has a default template-argument, all
5574 subsequent template-parameters shall have a default
5575 template-argument supplied. */
5577 {
5584 {
5594 {
5596 /* For better subsequent error-recovery, we indicate that
5597 there should have been a default argument. */
5600 }
5602 && !is_friend_decl
5603 /* Don't complain about an enclosing partial
5604 specialization. */
5609 /* A fixed parameter pack will be partially
5610 instantiated into a fixed length list. */
5612 {
5613 /* A primary class template, primary variable template
5614 (DR 2032), or alias template can only have one
5615 parameter pack, at the end of the template
5616 parameter list. */
5624 }
5625 }
5626 }
5627 }
5630 || is_partial
5631 || !is_primary
5633 /* For an ordinary class template, default template arguments are
5634 allowed at the innermost level, e.g.:
5635 template <class T = int>
5636 struct S {};
5637 but, in a partial specialization, they're not allowed even
5638 there, as we have in [temp.class.spec]:
5640 The template parameter list of a specialization shall not
5641 contain default template argument values.
5643 So, for a partial specialization, or for a function template
5644 (in C++98/C++03), we look at all of them. */
5645 ;
5646 else
5647 /* But, for a primary class template that is not a partial
5648 specialization we look at all template parameters except the
5649 innermost ones. */
5652 /* Figure out what error message to issue. */
5667 else
5668 /* Per [temp.param]/9, "A default template-argument shall not be
5669 specified in the template-parameter-lists of the definition of
5670 a member of a class template that appears outside of the member's
5671 class.", thus if we aren't handling a member of a class template
5672 there is no need to examine the parameters. */
5676 /* If we're inside a class definition, there's no need to
5677 examine the parameters to the class itself. On the one
5678 hand, they will be checked when the class is defined, and,
5679 on the other, default arguments are valid in things like:
5680 template <class T = double>
5681 struct S { template <class U> void f(U); };
5682 Here the default argument for `S' has no bearing on the
5683 declaration of `f'. */
5685 else
5686 /* Check everything. */
5692 {
5699 {
5704 {
5706 {
5713 }
5715 /* Clear out the default argument so that we are not
5716 confused later. */
5718 }
5719 }
5721 /* At this point, if we're still interested in issuing messages,
5722 they must apply to classes surrounding the object declared. */
5726 }
5729 }
5731 /* Worker for push_template_decl_real, called via
5732 for_each_template_parm. DATA is really an int, indicating the
5733 level of the parameters we are interested in. If T is a template
5734 parameter of that level, return nonzero. */
5736 static int
5738 {
5744 else
5747 }
5749 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5750 DATA is really an int, indicating the innermost outer level of parameters.
5751 If T is a template parameter of that level or further out, return
5752 nonzero. */
5754 static int
5756 {
5762 else
5765 }
5767 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5768 parameters given by current_template_args, or reuses a
5769 previously existing one, if appropriate. Returns the DECL, or an
5770 equivalent one, if it is replaced via a call to duplicate_decls.
5772 If IS_FRIEND is true, DECL is a friend declaration. */
5774 tree
5776 {
5780 /* See if this is a partial specialization. */
5789 /* No surprising friend functions. */
5794 tree ctx;
5796 /* For a friend, we want the context of the friend, not
5797 the type of which it is a friend. */
5801 /* In the case of a virtual function, we want the class in which
5802 it is defined. */
5804 else
5805 /* Otherwise, if we're currently defining some class, the DECL
5806 is assumed to be a member of the class. */
5815 /* See if this is a primary template. */
5819 /* A friend template that specifies a class context, i.e.
5820 template <typename T> friend void A<T>::f();
5821 is not primary. */
5822 ;
5824 /* Lambdas are not primary. */
5825 ;
5826 else
5829 /* True if the template is a member template, in the sense of
5830 [temp.mem]. */
5834 {
5842 {
5845 }
5847 {
5849 {
5852 }
5854 {
5855 /* [temp.mem]
5857 A destructor shall not be a member template. */
5861 }
5868 {
5869 /* [basic.stc.dynamic.allocation]
5871 An allocation function can be a function
5872 template. ... Template allocation functions shall
5873 have two or more parameters. */
5876 }
5877 }
5883 /* alias-declaration */
5889 else
5890 {
5893 }
5894 }
5901 /* Check to see that the rules regarding the use of default
5902 arguments are not being violated. We check args for a friend
5903 functions when we know whether it's a definition, introducing
5904 declaration or re-declaration. */
5909 /* Ensure that there are no parameter packs in the type of this
5910 declaration that have not been expanded. */
5912 {
5913 /* Check each of the arguments individually to see if there are
5914 any bare parameter packs. */
5920 {
5923 {
5924 /* This is a PARM_DECL that contains unexpanded parameter
5925 packs. We have already complained about this in the
5926 check_for_bare_parameter_packs call, so just replace
5927 these types with ERROR_MARK_NODE. */
5930 }
5934 }
5936 /* Check for bare parameter packs in the return type and the
5937 exception specifiers. */
5939 /* Errors were already issued, set return type to int
5940 as the frontend doesn't expect error_mark_node as
5941 the return type. */
5945 }
5946 else
5947 {
5951 {
5954 }
5959 }
5968 {
5969 /* Does not get a template head. */
5972 }
5979 {
5984 /* If DECL is a TYPE_DECL for a class-template, then there won't
5985 be DECL_LANG_SPECIFIC. The information equivalent to
5986 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5990 {
5991 /* Since a template declaration already existed for this
5992 class-type, we must be redeclaring it here. Make sure
5993 that the redeclaration is valid. */
5995 current_template_parms,
5997 /* We don't need to create a new TEMPLATE_DECL; just use the
5998 one we already had. */
6000 }
6001 else
6002 {
6004 member_template_p);
6009 {
6010 /* A specialization of a member template of a template
6011 class. */
6015 }
6016 }
6017 }
6018 else
6019 {
6025 {
6028 }
6036 {
6037 /* The declaration is a specialization of a member
6038 template, declared outside the class. Therefore, the
6039 innermost template arguments will be NULL, so we
6040 replace them with the arguments determined by the
6041 earlier call to check_explicit_specialization. */
6044 tree new_tmpl
6046 member_template_p);
6054 args,
6057 }
6059 /* Make sure the template headers we got make sense. */
6064 {
6069 }
6070 else
6072 {
6077 {
6081 else
6085 /* Avoid crash in import_export_decl. */
6088 }
6093 /* Can happen in erroneous input. */
6095 else
6097 }
6099 /* Check that the parms are used in the appropriate qualifying scopes
6100 in the declarator. */
6104 {
6110 /* Avoid crash in import_export_decl. */
6113 }
6114 }
6119 {
6120 /* Push template declarations for global functions and types.
6121 Note that we do not try to push a global template friend
6122 declared in a template class; such a thing may well depend on
6123 the template parameters of the class and we'll push it when
6124 instantiating the befriending class. */
6127 {
6132 /* pushdecl may have found an existing template. */
6134 {
6137 }
6138 }
6140 {
6141 /* Record this decl as belonging to the current class. It's
6142 not chained onto anything else. */
6146 }
6147 }
6149 /* The type may have been completed, or (erroneously) changed. */
6153 {
6155 {
6160 /* Give template template parms a DECL_CONTEXT of the template
6161 for which they are a parameter. */
6164 {
6168 }
6172 {
6175 {
6176 /* ??? Why don't we do this here for all templates? */
6179 }
6182 }
6183 }
6185 /* The DECL_TI_ARGS of DECL contains full set of arguments
6186 referring wback to its most general template. If TMPL is a
6187 specialization, ARGS may only have the innermost set of
6188 arguments. Add the missing argument levels if necessary. */
6196 else
6197 {
6200 }
6201 }
6204 && !is_friend
6207 /* Set DECL_COMDAT on template instantiations; if we force
6208 them to be emitted by explicit instantiation,
6209 mark_needed will tell cgraph to do the right thing. */
6215 }
6217 /* FN is an inheriting constructor that inherits from the constructor
6218 template INHERITED; turn FN into a constructor template with a matching
6219 template header. */
6221 tree
6223 {
6224 tree inner_parms
6227 tree parms
6236 }
6238 /* Called when a class template TYPE is redeclared with the indicated
6239 template PARMS, e.g.:
6241 template <class T> struct S;
6242 template <class T> struct S {}; */
6244 bool
6246 {
6247 tree tmpl;
6248 tree tmpl_parms;
6252 {
6255 }
6259 /* The type is nested in some template class. Nothing to worry
6260 about here; there are no new template parameters for the nested
6261 type. */
6265 {
6267 tmpl);
6269 }
6275 {
6285 }
6288 {
6289 tree tmpl_parm;
6290 tree parm;
6302 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6303 TEMPLATE_DECL. */
6313 {
6314 auto_diagnostic_group d;
6318 else
6321 }
6323 /* The parameters can be declared to introduce different
6324 constraints. */
6328 {
6329 auto_diagnostic_group d;
6335 }
6337 /* Give each template template parm in this redeclaration a
6338 DECL_CONTEXT of the template for which they are a parameter. */
6340 {
6343 }
6344 }
6353 /* Two classes with different constraints declare different entities. */
6355 {
6356 auto_diagnostic_group d;
6362 }
6365 }
6367 /* The actual substitution part of instantiate_non_dependent_expr,
6368 to be used when the caller has already checked
6369 !instantiation_dependent_uneval_expression_p (expr)
6370 and cleared processing_template_decl. */
6372 tree
6374 {
6377 complain,
6379 }
6381 /* Instantiate the non-dependent expression EXPR. */
6383 tree
6386 {
6391 {
6392 /* The caller should have checked this already. */
6394 processing_template_decl_sentinel s;
6396 }
6398 }
6400 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6401 expression is dependent or non-constant. */
6403 tree
6405 {
6409 {
6412 else
6413 {
6414 processing_template_decl_sentinel s;
6416 }
6417 }
6419 }
6421 /* True iff T is a specialization of a variable template. */
6423 bool
6425 {
6430 }
6432 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6433 template declaration, or a TYPE_DECL for an alias declaration. */
6435 bool
6437 {
6445 }
6447 /* If T is a specialization of an alias template, return it; otherwise return
6448 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6450 tree
6453 {
6457 /* It's an alias template specialization if it's an alias and its
6458 TYPE_NAME is a specialization of a primary template. */
6460 {
6467 transparent_typedefs);
6468 }
6471 }
6473 /* Data structure for complex_alias_template_*. */
6475 struct uses_all_template_parms_data
6476 {
6479 };
6481 /* walk_tree callback for complex_alias_template_p. */
6483 static tree
6485 {
6490 {
6495 {
6499 }
6502 }
6507 /* An alias template with a pack expansion that expands a pack from the
6508 enclosing class needs to be considered complex, to avoid confusion with
6509 the same pack being used as an argument to the alias's own template
6510 parameter (91966). */
6513 {
6522 /* Consider the expanded packs to be used outside the expansion... */
6524 }
6526 /* ...but don't walk into the pattern. Consider PR104008:
6528 template <typename T, typename... Ts>
6529 using IsOneOf = disjunction<is_same<T, Ts>...>;
6531 where IsOneOf seemingly uses all of its template parameters in its
6532 expansion (and does not expand a pack from the enclosing class), so the
6533 alias was not marked as complex. However, if it is used like
6534 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6535 expansion. So only Ts is considered used by the pack expansion. */
6539 }
6541 /* An alias template is complex from a SFINAE perspective if a template-id
6542 using that alias can be ill-formed when the expansion is not, as with
6543 the void_t template.
6545 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6546 template arguments are empty packs. */
6548 static bool
6550 {
6551 /* A renaming alias isn't complex. */
6555 /* Any other constrained alias is complex. */
6574 }
6576 /* If T is a specialization of a complex alias template with dependent
6577 template-arguments, return it; otherwise return NULL_TREE. If T is a
6578 typedef to such a specialization, return the specialization. */
6580 tree
6582 {
6593 && (any_dependent_template_arguments_p
6598 {
6601 }
6604 }
6606 /* Return the number of innermost template parameters in TMPL. */
6608 static int
6610 {
6613 }
6615 /* Return either TMPL or another template that it is equivalent to under DR
6616 1286: An alias that just changes the name of a template is equivalent to
6617 the other template. */
6619 static tree
6621 {
6624 {
6625 /* Determine if the alias is equivalent to an underlying template. */
6627 /* The underlying type may have been ill-formed. Don't proceed. */
6640 /* Does the alias add cv-quals? */
6648 /* Are any default template arguments equivalent? */
6653 {
6658 }
6660 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6661 it's appropriate to treat a less-constrained alias as equivalent. */
6665 /* Alias is equivalent. Strip it and repeat. */
6667 }
6668 top_break:;
6671 }
6673 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6674 must be a reference-to-function or a pointer-to-function type, as specified
6675 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6676 and check that the resulting function has external linkage. */
6678 static tree
6680 tsubst_flags_t complain)
6681 {
6684 linkage_kind linkage;
6702 /* [temp.arg.nontype]/1
6704 A template-argument for a non-type, non-template template-parameter
6705 shall be one of:
6706 [...]
6707 -- the address of an object or function with external [C++11: or
6708 internal] linkage. */
6712 {
6714 {
6721 else
6724 }
6726 }
6730 {
6732 {
6738 else
6742 }
6744 }
6746 accept:
6748 {
6751 else
6753 }
6758 }
6760 /* Subroutine of convert_nontype_argument.
6761 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6762 Emit an error otherwise. */
6764 static bool
6766 tsubst_flags_t complain)
6767 {
6783 {
6789 else
6791 }
6793 }
6795 /* Returns TRUE iff the address of OP is value-dependent.
6797 14.6.2.4 [temp.dep.temp]:
6798 A non-integral non-type template-argument is dependent if its type is
6799 dependent or it has either of the following forms
6800 qualified-id
6801 & qualified-id
6802 and contains a nested-name-specifier which specifies a class-name that
6803 names a dependent type.
6805 We generalize this to just say that the address of a member of a
6806 dependent class is value-dependent; the above doesn't cover the
6807 address of a static data member named with an unqualified-id. */
6809 static bool
6811 {
6814 /* We could use get_inner_reference here, but there's no need;
6815 this is only relevant for template non-type arguments, which
6816 can only be expressed as &id-expression. */
6818 {
6829 }
6832 }
6834 /* The next set of functions are used for providing helpful explanatory
6835 diagnostics for failed overload resolution. Their messages should be
6836 indented by two spaces for consistency with the messages in
6837 call.cc */
6839 static int
6841 {
6843 }
6845 /* Other failure functions should call this one, to provide a single function
6846 for setting a breakpoint on. */
6848 static int
6850 {
6852 }
6854 static int
6856 {
6861 }
6863 static int
6865 {
6871 }
6873 static int
6875 {
6879 }
6881 static int
6883 {
6886 " template parameter %qD is not a parameter pack, but "
6890 }
6892 static int
6894 {
6897 " template argument %qE does not match "
6901 }
6903 static int
6905 {
6909 }
6911 static int
6913 {
6919 }
6921 static int
6923 {
6925 {
6930 else
6932 " deduced conflicting values for non-type parameter "
6934 }
6936 }
6938 static int
6940 {
6943 " variable-sized array type %qT is not "
6945 arg);
6947 }
6949 static int
6951 {
6955 arg);
6957 }
6959 static int
6961 {
6963 {
6969 else
6974 }
6976 }
6978 static int
6980 {
6982 }
6984 static int
6987 {
6989 }
6991 static int
6994 {
7000 }
7002 static int
7005 {
7008 {
7016 }
7018 }
7020 static int
7022 {
7025 " template parameters of a template template argument are "
7028 }
7030 static int
7032 {
7038 }
7040 static int
7042 {
7047 }
7049 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7050 argument for TYPE, points to an unsuitable object.
7052 Also adjust the type of the index in C++20 array subobject references. */
7054 static bool
7056 {
7058 {
7059 CASE_CONVERT:
7061 complain);
7065 complain);
7068 {
7072 }
7076 {
7082 {
7086 /* Canonicalize array offsets to ptrdiff_t; how they were
7087 written doesn't matter for subobject identity. */
7090 }
7093 {
7096 "%qE is not a valid template argument of type %qT "
7099 }
7101 {
7104 "%qE is not a valid template argument of type %qT "
7108 }
7111 {
7114 "%qE is not a valid template argument of type %qT "
7117 }
7118 /* C++17: For a non-type template-parameter of reference or pointer
7119 type, the value of the constant expression shall not refer to (or
7120 for a pointer type, shall not be the address of):
7121 * a subobject (4.5),
7122 * a temporary object (15.2),
7123 * a string literal (5.13.5),
7124 * the result of a typeid expression (8.2.8), or
7125 * a predefined __func__ variable (11.4.1). */
7127 {
7130 decl);
7132 }
7134 && !(same_type_ignoring_top_level_qualifiers_p
7137 {
7142 }
7144 {
7148 decl);
7150 }
7151 }
7159 else
7160 {
7162 {
7165 "because %qD is a variable, not the address of "
7168 }
7169 else
7170 {
7176 }
7177 }
7178 }
7181 }
7183 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7184 template argument EXPR. */
7186 static tree
7188 {
7193 {
7198 }
7202 /* This is no longer a compound literal. */
7206 }
7208 /* The template arguments corresponding to template parameter objects of types
7209 that contain pointers to members. */
7213 /* Find or build an nttp object for (already-validated) EXPR with name
7214 NAME. */
7216 tree
7218 {
7235 {
7236 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7237 lower_var_init before we're done mangling. So store the original
7238 value elsewhere. */
7241 }
7246 }
7248 /* Return the actual template argument corresponding to template parameter
7249 object VAR. */
7251 tree
7253 {
7257 }
7259 /* Attempt to convert the non-type template parameter EXPR to the
7260 indicated TYPE. If the conversion is successful, return the
7261 converted value. If the conversion is unsuccessful, return
7262 NULL_TREE if we issued an error message, or error_mark_node if we
7263 did not. We issue error messages for out-and-out bad template
7264 parameters, but not simply because the conversion failed, since we
7265 might be just trying to do argument deduction. Both TYPE and EXPR
7266 must be non-dependent.
7268 The conversion follows the special rules described in
7269 [temp.arg.nontype], and it is much more strict than an implicit
7270 conversion.
7272 This function is called twice for each template argument (see
7273 lookup_template_class for a more accurate description of this
7274 problem). This means that we need to handle expressions which
7275 are not valid in a C++ source, but can be created from the
7276 first call (for instance, casts to perform conversions). These
7277 hacks can go away after we fix the double coercion problem. */
7279 static tree
7281 {
7282 tree expr_type;
7285 /* Detect immediately string literals as invalid non-type argument.
7286 This special-case is not needed for correctness (we would easily
7287 catch this later), but only to provide better diagnostic for this
7288 common user mistake. As suggested by DR 100, we do not mention
7289 linkage issues in the diagnostic as this is not the point. */
7291 {
7297 }
7299 /* Add the ADDR_EXPR now for the benefit of
7300 value_dependent_expression_p. */
7303 {
7307 }
7309 /* If we are in a template, EXPR may be non-dependent, but still
7310 have a syntactic, rather than semantic, form. For example, EXPR
7311 might be a SCOPE_REF, rather than the VAR_DECL to which the
7312 SCOPE_REF refers. Preserving the qualifying scope is necessary
7313 so that access checking can be performed when the template is
7314 instantiated -- but here we need the resolved form so that we can
7315 convert the argument. */
7327 /* If the argument is non-dependent, perform any conversions in
7328 non-dependent context as well. */
7336 else
7339 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7340 to a non-type argument of "nullptr". */
7344 /* In C++11, integral or enumeration non-type template arguments can be
7345 arbitrary constant expressions. Pointer and pointer to
7346 member arguments can be general constant expressions that evaluate
7347 to a null value, but otherwise still need to be of a specific form. */
7349 {
7351 /* A PTRMEM_CST is already constant, and a valid template
7352 argument for a parameter of pointer to member type, we just want
7353 to leave it in that form rather than lower it to a
7357 {
7358 /* C++17: A template-argument for a non-type template-parameter shall
7359 be a converted constant expression (8.20) of the type of the
7360 template-parameter. */
7363 /* Make sure we return NULL_TREE only if we have really issued
7364 an error, as described above. */
7367 {
7370 }
7374 /* EXPR may have become value-dependent. */
7376 }
7378 {
7384 }
7385 }
7389 else
7392 /* HACK: Due to double coercion, we can get a
7393 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7394 which is the tree that we built on the first call (see
7395 below when coercing to reference to object or to reference to
7396 function). We just strip everything and get to the arg.
7397 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7398 for examples. */
7400 {
7401 /* Check this before we strip *& to avoid redundancy. */
7410 {
7411 /* ??? Maybe we could use convert_from_reference here, but we
7412 would need to relax its constraints because the NOP_EXPR
7413 could actually change the type to something more cv-qualified,
7414 and this is not folded by convert_from_reference. */
7419 && (same_type_ignoring_top_level_qualifiers_p
7422 {
7425 }
7426 }
7427 }
7429 /* [temp.arg.nontype]/5, bullet 1
7431 For a non-type template-parameter of integral or enumeration type,
7432 integral promotions (_conv.prom_) and integral conversions
7433 (_conv.integral_) are applied. */
7436 {
7438 {
7443 }
7448 /* Notice that there are constant expressions like '4 % 0' which
7449 do not fold into integer constants. */
7451 {
7453 {
7457 else
7463 /* else cxx_constant_value complained but gave us
7464 a real constant, so go ahead. */
7466 {
7467 /* Some assemble time constant expressions like
7468 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7469 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7470 as we can emit them into .rodata initializers of
7471 variables, yet they can't fold into an INTEGER_CST at
7472 compile time. Refuse them here. */
7477 }
7478 }
7479 else
7481 }
7483 /* Avoid typedef problems. */
7486 }
7487 /* [temp.arg.nontype]/5, bullet 2
7489 For a non-type template-parameter of type pointer to object,
7490 qualification conversions (_conv.qual_) and the array-to-pointer
7491 conversion (_conv.array_) are applied. */
7493 {
7496 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7497 decay_conversion or an explicit cast. If it's a problematic cast,
7498 we'll complain about it below. */
7500 {
7505 {
7508 }
7509 }
7511 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7513 A template-argument for a non-type, non-template template-parameter
7514 shall be one of: [...]
7516 -- the name of a non-type template-parameter;
7517 -- the address of an object or function with external linkage, [...]
7518 expressed as "& id-expression" where the & is optional if the name
7519 refers to a function or array, or if the corresponding
7520 template-parameter is a reference.
7522 Here, we do not care about functions, as they are invalid anyway
7523 for a parameter of type pointer-to-object. */
7526 /* Non-type template parameters are OK. */
7527 ;
7532 /* Other values, like integer constants, might be valid
7533 non-type arguments of some other type. */
7543 }
7544 /* [temp.arg.nontype]/5, bullet 3
7546 For a non-type template-parameter of type reference to object, no
7547 conversions apply. The type referred to by the reference may be more
7548 cv-qualified than the (otherwise identical) type of the
7549 template-argument. The template-parameter is bound directly to the
7550 template-argument, which must be an lvalue. */
7552 {
7554 expr_type))
7558 {
7563 }
7566 {
7571 }
7573 /* [temp.arg.nontype]/1
7575 A template-argument for a non-type, non-template template-parameter
7576 shall be one of: [...]
7578 -- the address of an object or function with external linkage. */
7581 {
7584 {
7587 "because a reference variable does not have a constant "
7590 }
7591 }
7594 /* OK, dependent reference. We don't want to ask whether a DECL is
7596 else
7597 {
7602 }
7606 }
7607 /* [temp.arg.nontype]/5, bullet 4
7609 For a non-type template-parameter of type pointer to function, only
7610 the function-to-pointer conversion (_conv.func_) is applied. If the
7611 template-argument represents a set of overloaded functions (or a
7612 pointer to such), the matching function is selected from the set
7613 (_over.over_). */
7615 {
7616 /* If the argument is a template-id, we might not have enough
7617 context information to decay the pointer. */
7619 {
7623 }
7626 /* Null pointer values are OK in C++11. */
7632 }
7633 /* [temp.arg.nontype]/5, bullet 5
7635 For a non-type template-parameter of type reference to function, no
7636 conversions apply. If the template-argument represents a set of
7637 overloaded functions, the matching function is selected from the set
7638 (_over.over_). */
7640 {
7642 {
7644 {
7649 }
7651 }
7656 }
7657 /* [temp.arg.nontype]/5, bullet 6
7659 For a non-type template-parameter of type pointer to member function,
7660 no conversions apply. If the template-argument represents a set of
7661 overloaded member functions, the matching member function is selected
7662 from the set (_over.over_). */
7664 {
7669 /* [temp.arg.nontype] bullet 1 says the pointer to member
7670 expression must be a pointer-to-member constant. */
7675 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7676 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7679 }
7680 /* [temp.arg.nontype]/5, bullet 7
7682 For a non-type template-parameter of type pointer to data member,
7683 qualification conversions (_conv.qual_) are applied. */
7685 {
7686 /* [temp.arg.nontype] bullet 1 says the pointer to member
7687 expression must be a pointer-to-member constant. */
7695 }
7697 {
7699 {
7704 }
7706 }
7708 {
7709 /* Replace the argument with a reference to the corresponding template
7710 parameter object. */
7715 }
7716 /* A template non-type parameter must be one of the above. */
7717 else
7720 /* Sanity check: did we actually convert the argument to the
7721 right type? */
7725 }
7727 /* Subroutine of coerce_template_template_parms, which returns 1 if
7728 PARM_PARM and ARG_PARM match using the rule for the template
7729 parameters of template template parameters. Both PARM and ARG are
7730 template parameters; the rest of the arguments are the same as for
7731 coerce_template_template_parms.
7732 */
7733 static int
7735 tree arg,
7736 tsubst_flags_t complain,
7737 tree in_decl,
7738 tree outer_args)
7739 {
7748 {
7750 /* We encounter instantiations of templates like
7751 template <template <template <class> class> class TT>
7752 class C; */
7753 {
7760 }
7761 /* Fall through. */
7766 /* Argument is a parameter pack but parameter is not. */
7771 /* The tsubst call is used to handle cases such as
7773 template <int> class C {};
7774 template <class T, template <T> class TT> class D {};
7775 D<int, C> d;
7777 i.e. the parameter list of TT depends on earlier parameters. */
7779 {
7784 }
7788 /* Argument is a parameter pack but parameter is not. */
7795 }
7798 }
7800 /* Coerce template argument list ARGLIST for use with template
7801 template-parameter TEMPL. */
7803 static tree
7805 tsubst_flags_t complain)
7806 {
7807 /* Consider an example where a template template parameter declared as
7809 template <class T, class U = std::allocator<T> > class TT
7811 The template parameter level of T and U are one level larger than
7812 of TT. To proper process the default argument of U, say when an
7813 instantiation `TT<int>' is seen, we need to build the full
7814 arguments containing {int} as the innermost level. Outer levels,
7815 available when not appearing as default template argument, can be
7816 obtained from the arguments of the enclosing template.
7818 Suppose that TT is later substituted with std::vector. The above
7819 instantiation is `TT<int, std::allocator<T> >' with TT at
7820 level 1, and T at level 2, while the template arguments at level 1
7821 becomes {std::vector} and the inner level 2 is {int}. */
7827 {
7828 /* This is an argument of the current template, so we haven't set
7829 DECL_CONTEXT yet. */
7830 tree relevant_template_parms;
7832 /* Parameter levels that are greater than the level of the given
7833 template template parm are irrelevant. */
7840 }
7847 }
7849 /* A cache of template template parameters with match-all default
7850 arguments. */
7853 /* T is a bound template template-parameter. Copy its arguments into default
7854 arguments of the template template-parameter's template parameters. */
7856 static tree
7858 {
7881 {
7884 {
7887 }
7888 }
7892 }
7894 /* ARG is a bound potential template template-argument, and PARGS is a list
7895 of arguments for the corresponding template template-parameter. Adjust
7896 PARGS as appropriate for application to ARG's template, and if ARG is a
7897 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7898 arguments to the template template parameter. */
7900 static tree
7902 {
7906 {
7907 /* When comparing two template template-parameters in partial ordering,
7908 rewrite the one currently being used as an argument to have default
7909 arguments for all parameters. */
7915 }
7916 else
7917 {
7918 tree aparms
7921 }
7924 }
7926 /* Subroutine of unify for the case when PARM is a
7927 BOUND_TEMPLATE_TEMPLATE_PARM. */
7929 static int
7932 {
7936 /* The template template parm might be variadic and the argument
7937 not, so flatten both argument lists. */
7942 {
7943 /* In keeping with P0522R0, adjust P's template arguments
7944 to apply to A's template; then flatten it again. */
7952 /* If the P0522 adjustment eliminated a pack expansion, deduce
7953 empty packs. */
7959 }
7960 else
7961 {
7962 /* Deduce arguments T, i from TT<T> or TT<i>.
7963 We check each element of PARMVEC and ARGVEC individually
7964 rather than the whole TREE_VEC since they can have
7965 different number of elements, which is allowed under N2555. */
7969 /* Check if the parameters end in a pack, making them
7970 variadic. */
7977 /* If the template argument list of P contains a pack
7978 expansion that is not the last template argument, the
7979 entire template argument list is a non-deduced
7980 context. */
7998 DEDUCE_EXACT,
8001 }
8004 }
8006 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
8007 template template parameters. Both PARM_PARMS and ARG_PARMS are
8008 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
8009 or PARM_DECL.
8011 Consider the example:
8012 template <class T> class A;
8013 template<template <class U> class TT> class B;
8015 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
8016 the parameters to A, and OUTER_ARGS contains A. */
8018 static int
8020 tree arg_parms_full,
8021 tsubst_flags_t complain,
8022 tree in_decl,
8023 tree outer_args)
8024 {
8039 {
8040 /* P0522R0: A template template-parameter P is at least as specialized as
8041 a template template-argument A if, given the following rewrite to two
8042 function templates, the function template corresponding to P is at
8043 least as specialized as the function template corresponding to A
8044 according to the partial ordering rules for function templates
8045 ([temp.func.order]). Given an invented class template X with the
8046 template parameter list of A (including default arguments):
8048 * Each of the two function templates has the same template parameters,
8049 respectively, as P or A.
8051 * Each function template has a single function parameter whose type is
8052 a specialization of X with template arguments corresponding to the
8053 template parameters from the respective function template where, for
8054 each template parameter PP in the template parameter list of the
8055 function template, a corresponding template argument AA is formed. If
8056 PP declares a parameter pack, then AA is the pack expansion
8057 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8059 If the rewrite produces an invalid type, then P is not at least as
8060 specialized as A. */
8062 /* So coerce P's args to apply to A's parms, and then deduce between A's
8063 args and the converted args. If that succeeds, A is at least as
8064 specialized as P, so they match.*/
8070 /* PARM, and thus the context in which we are passing ARG to it, may be
8071 at a deeper level than ARG; when trying to coerce to ARG_PARMS, we
8072 want to provide the right number of levels, so we reduce the number of
8073 levels in OUTER_ARGS before prepending them. This is most important
8074 when ARG is a namespace-scope template, as in alias-decl-ttp2.C.
8076 ARG might also be deeper than PARM (ttp23). In that case, we include
8077 all of OUTER_ARGS. The missing levels seem potentially problematic,
8078 but I can't come up with a testcase that breaks. */
8080 {
8085 }
8089 {
8095 }
8096 }
8098 /* Determine whether we have a parameter pack at the end of the
8099 template template parameter's template parameter list. */
8101 {
8108 {
8122 }
8123 }
8129 /* Check all of the template parameters except the parameter pack at
8130 the end (if any). */
8132 {
8141 outer_args))
8144 }
8147 {
8148 /* Check each of the template parameters in the template
8149 argument against the template parameter pack at the end of
8150 the template template parameter. */
8157 {
8164 outer_args))
8166 }
8167 }
8170 }
8172 /* Verifies that the deduced template arguments (in TARGS) for the
8173 template template parameters (in TPARMS) represent valid bindings,
8174 by comparing the template parameter list of each template argument
8175 to the template parameter list of its corresponding template
8176 template parameter, in accordance with DR150. This
8177 routine can only be called after all template arguments have been
8178 deduced. It will return TRUE if all of the template template
8179 parameter bindings are okay, FALSE otherwise. */
8180 bool
8182 {
8186 /* We're dealing with template parms in this process. */
8192 {
8197 {
8202 {
8203 /* Look inside the argument pack. */
8206 }
8209 {
8213 /* Extract the next argument from the argument
8214 pack. */
8218 /* Look at the pattern of the pack expansion. */
8221 /* Extract the template parameters from the template
8222 argument. */
8228 /* Verify that we can coerce the template template
8229 parameters from the template argument to the template
8230 parameter. This requires an exact match. */
8232 && !coerce_template_template_parms
8234 targ_parms,
8235 tf_none,
8236 tparm,
8237 targs))
8238 {
8241 }
8242 }
8243 }
8244 }
8246 out:
8250 }
8252 /* Since type attributes aren't mangled, we need to strip them from
8253 template type arguments. */
8255 tree
8257 {
8267 }
8269 /* And from inside dependent non-type arguments like sizeof(Type). */
8271 static tree
8273 {
8283 }
8285 /* A template declaration can be substituted for a constrained
8286 template template parameter only when the argument is no more
8287 constrained than the parameter. */
8289 static bool
8291 {
8294 /* For now, allow constrained template template arguments
8295 and unconstrained template template parameters. */
8299 /* If the template parameter is constrained, we need to rewrite its
8300 constraints in terms of the ARG's template parameters. This ensures
8301 that all of the template parameter types will have the same depth.
8303 Note that this is only valid when coerce_template_template_parm is
8304 true for the innermost template parameters of PARM and ARG. In other
8305 words, because coercion is successful, this conversion will be valid. */
8308 {
8317 }
8320 }
8322 // Convert a placeholder argument into a binding to the original
8323 // parameter. The original parameter is saved as the TREE_TYPE of
8324 // ARG.
8327 {
8330 }
8332 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8333 because one of them is dependent. But we need to represent the
8334 conversion for the benefit of cp_tree_equal. */
8336 static tree
8338 {
8339 /* Auto parms get no conversion. */
8342 /* We don't need or want to add this conversion now if we're going to use the
8343 argument for deduction. */
8355 }
8357 /* Convert the indicated template ARG as necessary to match the
8358 indicated template PARM. Returns the converted ARG, or
8359 error_mark_node if the conversion was unsuccessful. Error and
8360 warning messages are issued under control of COMPLAIN. This
8361 conversion is for the Ith parameter in the parameter list. ARGS is
8362 the full set of template arguments deduced so far. */
8364 static tree
8366 tree arg,
8367 tree args,
8368 tsubst_flags_t complain,
8370 tree in_decl)
8371 {
8372 tree orig_arg;
8373 tree val;
8379 /* Trivially convert placeholders. */
8388 {
8389 /* The template argument was the name of some
8390 member function. That's usually
8391 invalid, but static members are OK. In any
8392 case, grab the underlying fields/functions
8393 and issue an error later if required. */
8395 }
8403 /* When determining whether an argument pack expansion is a template,
8404 look at the pattern. */
8408 /* Deal with an injected-class-name used as a template template arg. */
8410 {
8413 {
8423 }
8424 }
8426 is_tmpl_type =
8442 {
8444 {
8448 }
8451 "to refer to a type member of a template parameter, "
8456 typename_type,
8457 complain);
8460 }
8462 {
8464 {
8466 {
8471 {
8472 /* The template argument is a type, but we're expecting
8473 an expression. */
8478 /* [temp.arg]/2: "In a template-argument, an ambiguity
8479 between a type-id and an expression is resolved to a
8480 type-id, regardless of the form of the corresponding
8481 template-parameter." So give the user a clue. */
8484 "for non-type template parameter is treated as "
8486 }
8490 else
8493 }
8494 }
8496 }
8498 {
8500 {
8507 else
8510 }
8512 }
8515 /* We already did the appropriate conversion when packing args. */
8518 {
8520 {
8522 /* The number of argument required is not known yet.
8523 Just accept it for now. */
8525 else
8526 {
8528 tree argparm;
8530 /* Strip alias templates that are equivalent to another
8531 template. */
8537 args))
8538 {
8541 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8542 TEMPLATE_DECL. */
8544 {
8549 }
8550 }
8551 else
8552 {
8554 {
8561 }
8564 }
8566 // Check that the constraints are compatible before allowing the
8567 // substitution.
8570 {
8572 {
8578 }
8580 }
8581 }
8582 }
8583 else
8585 /* We only form one instance of each template specialization.
8586 Therefore, if we use a non-canonical variant (i.e., a
8587 typedef), any future messages referring to the type will use
8588 the typedef, which is confusing if those future uses do not
8589 themselves also use the typedef. */
8592 }
8593 else
8594 {
8599 /* We don't have enough levels of args to do any substitution. This
8602 {
8604 LOOKUP_IMPLICIT);
8607 }
8608 else
8611 /* Perform array-to-pointer and function-to-pointer conversion
8612 as per [temp.param]/10. */
8618 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8619 this non-type template parameter, as per [temp.param]/6. */
8627 /* We used to call digest_init here. However, digest_init
8628 will report errors, which we don't want when complain
8629 is zero. More importantly, digest_init will try too
8630 hard to convert things: for example, `0' should not be
8631 converted to pointer type at this point according to
8632 the standard. Accepting this is not merely an
8633 extension, since deciding whether or not these
8634 conversions can occur is part of determining which
8635 function template to call, or whether a given explicit
8636 argument specification is valid. */
8638 else
8639 {
8642 }
8653 {
8654 /* Reject template arguments that are references to built-in
8655 functions with no library fallbacks. */
8664 }
8667 {
8668 /* Strip typedefs from the SCOPE_REF. */
8671 complain);
8674 }
8675 }
8678 }
8680 /* Coerces the remaining template arguments in INNER_ARGS (from
8681 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8682 Returns the coerced argument pack. PARM_IDX is the position of this
8683 parameter in the template parameter list. ARGS is the original
8684 template argument list. */
8685 static tree
8688 tree args,
8689 tree inner_args,
8691 tree new_args,
8693 tree in_decl,
8694 tsubst_flags_t complain)
8695 {
8698 tree packed_args;
8699 tree argument_pack;
8706 {
8707 /* When the template parameter is a non-type template parameter pack
8708 or template template parameter pack whose type or template
8709 parameters use parameter packs, we know exactly how many arguments
8710 we are looking for. Build a vector of the instantiated decls for
8711 these template parameters in PACKED_PARMS. */
8712 /* We can't use make_pack_expansion here because it would interpret a
8713 _DECL as a use rather than a declaration. */
8727 /* If we're doing a partial instantiation of a member template,
8728 verify that all of the types used for the non-type
8729 template parameter pack are, in fact, valid for non-type
8730 template parameters. */
8733 {
8736 {
8741 }
8742 /* We don't know how many args we have yet, just
8743 use the unconverted ones for now. */
8745 }
8748 }
8749 /* Check if we have a placeholder pack, which indicates we're
8750 in the context of a introduction list. In that case we want
8751 to match this pack to the single placeholder. */
8755 {
8758 }
8759 else
8762 /* Convert the remaining arguments, which will be a part of the
8763 parameter pack "parm". */
8766 {
8772 {
8773 /* Once we've packed as many args as we have types, stop. */
8777 /* We don't know how many args we have yet, just
8778 use the unconverted ones for now. */
8780 else
8782 }
8785 {
8788 }
8789 else
8792 in_decl);
8796 }
8800 {
8805 }
8810 else
8811 {
8814 }
8821 }
8823 /* Returns the number of pack expansions in the template argument vector
8824 ARGS. */
8826 static int
8828 {
8833 {
8837 }
8839 }
8841 /* Convert all template arguments to their appropriate types, and
8842 return a vector containing the innermost resulting template
8843 arguments. If any error occurs, return error_mark_node. Error and
8844 warning messages are issued under control of COMPLAIN.
8846 If PARMS represents all template parameters levels, this function
8847 returns a vector of vectors representing all the resulting argument
8848 levels. Note that in this case, only the innermost arguments are
8849 coerced because the outermost ones are supposed to have been coerced
8850 already. Otherwise, if PARMS represents only (the innermost) vector
8851 of parameters, this function returns a vector containing just the
8852 innermost resulting arguments.
8854 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8855 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
8856 arguments not specified in ARGS must have default arguments which
8857 we'll use to fill in ARGS. */
8859 tree
8861 tree args,
8862 tree in_decl,
8863 tsubst_flags_t complain,
8865 {
8867 tree orig_inner_args;
8868 tree inner_args;
8870 /* When used as a boolean value, indicates whether this is a
8871 variadic template parameter list. Since it's an int, we can also
8872 subtract it from nparms to get the number of non-variadic
8873 parameters. */
8878 /* Adjustment to nparms for fixed parameter packs. */
8883 /* Likewise for parameters with default arguments. */
8891 {
8893 {
8896 }
8898 }
8902 /* Determine if there are any parameter packs or default arguments. */
8904 {
8912 }
8915 /* If there are no parameters that follow a parameter pack, we need to
8916 expand any argument packs so that we can deduce a parameter pack from
8917 some non-packed args followed by an argument pack, as in variadic85.C.
8918 If there are such parameters, we need to leave argument packs intact
8919 so the arguments are assigned properly. This can happen when dealing
8920 with a nested class inside a partial specialization of a class
8921 template, as in variadic92.C, or when deducing a template parameter pack
8922 from a sub-declarator, as in variadic114.C. */
8926 /* Count any pack expansion args. */
8932 && require_all_args
8933 && !variadic_args_p
8936 {
8937 bad_nargs:
8939 {
8941 {
8945 }
8946 else
8953 }
8956 }
8957 /* We can't pass a pack expansion to a non-pack parameter of an alias
8958 template (DR 1430). */
8962 && variadic_args_p
8964 {
8966 {
8968 {
8974 {
8977 "pack expansion argument for non-pack parameter "
8979 else
8981 "pack expansion argument for non-pack parameter "
8985 }
8986 }
8988 found:;
8989 }
8991 }
8993 /* We need to evaluate the template arguments, even though this
8994 template-id may be nested within a "sizeof". */
8995 cp_evaluated ev;
9001 {
9002 tree arg;
9003 tree parm;
9005 /* Get the Ith template parameter. */
9009 {
9012 }
9014 /* Calculate the next argument. */
9017 else
9023 {
9024 /* Some arguments will be placed in the
9025 template parameter pack PARM. */
9032 {
9033 /* We don't know how many args we have yet, just use the
9034 unconverted (and still packed) ones for now. */
9038 }
9042 /* Store this argument. */
9044 {
9045 lost++;
9046 /* We are done with all of the arguments. */
9049 }
9050 else
9051 {
9055 {
9058 }
9059 }
9062 }
9064 {
9066 {
9067 /* "If every valid specialization of a variadic template
9068 requires an empty template parameter pack, the template is
9069 ill-formed, no diagnostic required." So check that the
9070 pattern works with this parameter. */
9075 in_decl);
9077 {
9082 }
9084 /* Recover from missing typename. */
9088 /* We don't know how many args we have yet, just
9089 use the unconverted ones for now. */
9093 }
9094 }
9096 {
9097 /* There must be a default arg in this case. */
9100 /* The position of the first default template argument,
9101 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9102 Record that. */
9106 }
9107 else
9111 {
9114 }
9116 {
9117 /* This can occur if there was an error in the template
9118 parameter list itself (which we would already have
9119 reported) that we are trying to recover from, e.g., a class
9120 template with a parameter list such as
9121 template<typename..., typename> (cpp0x/variadic150.C). */
9124 /* This can also happen with a fixed parameter pack (71834). */
9127 }
9128 else
9134 lost++;
9137 }
9140 {
9141 /* If we had fixed parameter packs, we didn't know how many arguments we
9142 actually needed earlier; now we do. */
9146 }
9149 {
9150 /* We had some pack expansion arguments that will only work if the packs
9151 are empty, but wait until instantiation time to complain.
9152 See variadic-ttp3.C. */
9154 /* Except that we can't provide empty packs to alias templates or
9155 concepts when there are no corresponding parameters. Basically,
9156 we can get here with this:
9158 template<typename T> concept C = true;
9160 template<typename... Args>
9161 requires C<Args...>
9162 void f();
9164 When parsing C<Args...>, we try to form a concept check of
9165 C<?, Args...>. Without the extra check for substituting an empty
9166 pack past the last parameter, we can accept the check as valid.
9168 FIXME: This may be valid for alias templates (but I doubt it).
9170 FIXME: The error could be better also. */
9172 {
9177 }
9188 }
9191 {
9194 }
9201 }
9203 /* Returns true if T is a wrapper to make a C++20 template parameter
9204 object const. */
9206 static bool
9208 {
9214 }
9216 /* Returns 1 if template args OT and NT are equivalent. */
9218 int
9220 {
9233 /* DR 1558: Don't treat an alias template specialization with dependent
9234 arguments as equivalent to its underlying type when used as a template
9235 argument; we need them to be distinct so that we substitute into the
9236 specialization arguments at instantiation time. And aliases can't be
9237 equivalent without being ==, so we don't need to look any deeper.
9239 During partial ordering, however, we need to treat them normally so we can
9240 order uses of the same alias with different cv-qualification (79960). */
9246 /* For member templates */
9259 {
9263 }
9264 else
9265 {
9266 /* Try to treat a template non-type argument that has been converted
9267 to the parameter type as equivalent to one that hasn't yet. */
9281 }
9282 }
9284 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9285 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9286 NEWARG_PTR with the offending arguments if they are non-NULL. */
9288 bool
9292 {
9303 {
9308 {
9314 }
9315 }
9317 }
9321 {
9323 }
9325 /* Implement a freelist interface for objects of type T.
9327 Head is a separate object, rather than a regular member, so that we
9328 can define it as a GTY deletable pointer, which is highly
9329 desirable. A data member could be declared that way, but then the
9330 containing object would implicitly get GTY((user)), which would
9331 prevent us from instantiating freelists as global objects.
9332 Although this way we can create freelist global objects, they're
9333 such thin wrappers that instantiating temporaries at every use
9334 loses nothing and saves permanent storage for the freelist object.
9336 Member functions next, anew, poison and reinit have default
9337 implementations that work for most of the types we're interested
9338 in, but if they don't work for some type, they should be explicitly
9339 specialized. See the comments before them for requirements, and
9340 the example specializations for the tree_list_freelist. */
9342 class freelist
9343 {
9344 /* Return the next object in a chain. We could just do type
9345 punning, but if we access the object with its underlying type, we
9346 avoid strict-aliasing trouble. This needs only work between
9347 poison and reinit. */
9350 /* Return a newly allocated, uninitialized or minimally-initialized
9351 object of type T. Any initialization performed by anew should
9352 either remain across the life of the object and the execution of
9353 poison, or be redone by reinit. */
9356 /* Optionally scribble all over the bits holding the object, so that
9357 they become (mostly?) uninitialized memory. This is called while
9358 preparing to make the object part of the free list. */
9363 #ifdef ENABLE_GC_CHECKING
9364 /* Poison the data, to indicate the data is garbage. */
9367 #endif
9368 /* Let valgrind know the object is free. */
9371 /* Let valgrind know the next portion of the object is available,
9372 but uninitialized. */
9374 }
9376 /* Bring an object that underwent at least one lifecycle after anew
9377 and before the most recent free and poison, back to a usable
9378 state, reinitializing whatever is needed for it to be
9379 functionally equivalent to an object just allocated and returned
9380 by anew. This may poison or clear the next field, used by
9381 freelist housekeeping after poison was called. */
9385 #ifdef ENABLE_GC_CHECKING
9387 #endif
9388 /* Let valgrind know the entire object is available, but
9389 uninitialized. */
9391 }
9393 /* Reference a GTY-deletable pointer that points to the first object
9394 in the free list proper. */
9397 /* Construct a freelist object chaining objects off of HEAD. */
9400 /* Add OBJ to the free object list. The former head becomes OBJ's
9401 successor. */
9403 {
9407 }
9409 /* Take an object from the free list, if one is available, or
9410 allocate a new one. Objects taken from the free list should be
9411 regarded as filled with garbage, except for bits that are
9412 configured to be preserved across free and alloc. */
9414 {
9416 {
9421 }
9422 else
9424 }
9425 };
9427 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9428 want to allocate a TREE_LIST using the usual interface, and ensure
9429 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9430 build_tree_list logic in reinit, so this could go out of sync. */
9434 {
9436 }
9438 inline tree
9440 {
9442 }
9446 {
9452 #ifdef ENABLE_GC_CHECKING
9455 /* Poison the data, to indicate the data is garbage. */
9458 #endif
9459 /* Let valgrind know the object is free. */
9461 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9465 #ifdef ENABLE_GC_CHECKING
9467 /* Keep TREE_CHAIN functional. */
9469 #else
9471 #endif
9472 }
9476 {
9479 #ifdef ENABLE_GC_CHECKING
9483 #endif
9485 /* Let valgrind know the entire object is available, but
9486 uninitialized. */
9489 #ifdef ENABLE_GC_CHECKING
9491 #else
9493 #endif
9494 }
9496 /* Point to the first object in the TREE_LIST freelist. */
9498 /* Return the/an actual TREE_LIST freelist. */
9501 {
9503 }
9505 /* Point to the first object in the tinst_level freelist. */
9507 /* Return the/an actual tinst_level freelist. */
9510 {
9512 }
9514 /* Point to the first object in the pending_template freelist. */
9516 /* Return the/an actual pending_template freelist. */
9519 {
9521 }
9523 /* Build the TREE_LIST object out of a split list, store it
9524 permanently, and return it. */
9525 tree
9527 {
9536 }
9540 /* Increment OBJ's refcount unless it is already infinite. */
9543 {
9547 }
9549 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9550 void
9552 {
9556 }
9558 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9559 OBJ's DECL and OBJ, and start over with the tinst_level object that
9560 used to be referenced by OBJ's NEXT. */
9561 static void
9563 {
9567 {
9571 }
9572 }
9574 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9575 and of the former PTR. Omitting the second argument is equivalent
9576 to passing (T*)NULL; this is allowed because passing the
9577 zero-valued integral constant NULL confuses type deduction and/or
9578 overload resolution. */
9580 static void
9582 {
9586 }
9588 static void
9590 {
9600 /* We are called both from instantiate_decl, where we've already had a
9601 tinst_level pushed, and instantiate_template, where we haven't.
9602 Compensate. */
9604 level = !current_tinst_level
9616 else
9625 }
9628 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9629 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9630 documentation for TEMPLATE_ID_EXPR. */
9632 tree
9634 {
9641 {
9644 }
9647 {
9650 unknown_type_node,
9652 arglist);
9654 }
9657 }
9659 /* Within the scope of a template class S<T>, the name S gets bound
9660 (in build_self_reference) to a TYPE_DECL for the class, not a
9661 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9662 or one of its enclosing classes, and that type is a template,
9663 return the associated TEMPLATE_DECL. Otherwise, the original
9664 DECL is returned.
9666 Also handle the case when DECL is a TREE_LIST of ambiguous
9667 injected-class-names from different bases. */
9669 tree
9671 {
9675 /* DR 176: A lookup that finds an injected-class-name (10.2
9676 [class.member.lookup]) can result in an ambiguity in certain cases
9677 (for example, if it is found in more than one base class). If all of
9678 the injected-class-names that are found refer to specializations of
9679 the same class template, and if the name is followed by a
9680 template-argument-list, the reference refers to the class template
9681 itself and not a specialization thereof, and is not ambiguous. */
9683 {
9686 {
9692 }
9695 else
9697 }
9703 }
9705 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9706 parameters, find the desired type.
9708 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9710 IN_DECL, if non-NULL, is the template declaration we are trying to
9711 instantiate.
9713 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9714 the class we are looking up.
9716 Issue error and warning messages under control of COMPLAIN.
9718 If the template class is really a local class in a template
9719 function, then the FUNCTION_CONTEXT is the function in which it is
9720 being instantiated.
9722 ??? Note that this function is currently called *twice* for each
9723 template-id: the first time from the parser, while creating the
9724 incomplete type (finish_template_type), and the second type during the
9725 real instantiation (instantiate_template_class). This is surely something
9726 that we want to avoid. It also causes some problems with argument
9727 coercion (see convert_nontype_argument for more information on this). */
9729 tree
9732 {
9736 tree t;
9739 spec_entry elt;
9740 hashval_t hash;
9743 {
9747 else
9748 {
9755 }
9756 }
9758 {
9761 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9762 an implicit typename for the second A. Deal with it. */
9767 {
9770 }
9771 }
9774 {
9777 }
9779 {
9782 }
9784 {
9787 }
9789 /* Issue an error message if we didn't find a template. */
9791 {
9795 }
9798 /* Make sure it's a user visible template, if it was named by
9799 the user. */
9802 {
9804 {
9808 }
9810 }
9814 /* An alias that just changes the name of a template is equivalent to the
9815 other template, so if any of the arguments are pack expansions, strip
9816 the alias to avoid problems with a pack expansion passed to a non-pack
9817 alias template parameter (DR 1430). */
9822 {
9823 tree parm;
9832 }
9833 else
9834 {
9836 tree gen_tmpl;
9837 tree type_decl;
9845 /* An error occurred while building the template TEMPL, and a
9846 diagnostic has most certainly been emitted for that
9847 already. Let's propagate that error. */
9859 {
9860 /* We've been given an incomplete set of template arguments.
9861 For example, given:
9863 template <class T> struct S1 {
9864 template <class U> struct S2 {};
9865 template <class U> struct S2<U*> {};
9866 };
9868 we will be called with an ARGLIST of `U*', but the
9869 TEMPLATE will be `template <class T> template
9870 <class U> struct S1<T>::S2'. We must fill in the missing
9871 arguments. */
9875 }
9877 /* Now we should have enough arguments. */
9880 /* From here on, we're only interested in the most general
9881 template. */
9883 /* Shortcut looking up the current class scope again. */
9890 /* Calculate the BOUND_ARGS. These will be the args that are
9891 actually tsubst'd into the definition to create the
9892 instantiation. */
9896 /* We were unable to bind the arguments. */
9899 /* In the scope of a template class, explicit references to the
9900 template class refer to the type of the template, not any
9901 instantiation of it. For example, in:
9903 template <class T> class C { void f(C<T>); }
9905 the `C<T>' is just the same as `C'. Outside of the
9906 class, however, such a reference is an instantiation. */
9910 {
9915 }
9917 /* If we already have this specialization, return it. */
9927 /* If the template's constraints are not satisfied,
9928 then we cannot form a valid type.
9930 Note that the check is deferred until after the hash
9931 lookup. This prevents redundant checks on previously
9932 instantiated specializations. */
9936 {
9938 {
9939 auto_diagnostic_group d;
9942 }
9944 }
9948 /* If the deduced arguments are invalid, then the binding
9949 failed. */
9953 complain))
9960 /* This occurs when the user has tried to define a tagged type
9961 in a scope that forbids it. We emitted an error during the
9962 parse. We didn't complete the bail out then, so here we
9963 are. */
9968 {
9970 /* If the context of the partially instantiated template is
9971 already non-dependent, then we might as well use it. */
9973 else
9974 {
9977 /* Try completing the enclosing context if it's not already so. */
9980 {
9983 {
9984 /* Completion could have caused us to register the desired
9985 specialization already, so check the table again. */
9989 }
9990 }
9991 }
9992 }
9993 else
10002 /* Create the type. */
10004 {
10005 /* The user referred to a specialization of an alias
10006 template represented by GEN_TMPL.
10008 [temp.alias]/2 says:
10010 When a template-id refers to the specialization of an
10011 alias template, it is equivalent to the associated
10012 type obtained by substitution of its
10013 template-arguments for the template-parameters in the
10014 type-id of the alias template. */
10017 /* Note that the call above (by indirectly calling
10018 register_specialization in tsubst_decl) registers the
10019 TYPE_DECL representing the specialization of the alias
10020 template. So next time someone substitutes ARGLIST for
10021 the template parms into the alias template (GEN_TMPL),
10022 she'll get that TYPE_DECL back. */
10026 }
10028 {
10030 {
10041 }
10042 else
10043 {
10044 /* We don't want to call start_enum for this type, since
10045 the values for the enumeration constants may involve
10046 template parameters. And, no one should be interested
10047 in the enumeration constants for such a type. */
10050 }
10054 }
10056 {
10057 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10058 instantiated here. */
10066 /* A local class. Make sure the decl gets registered properly. */
10073 /* This instantiation is another name for the primary
10074 template type. Set the TYPE_CANONICAL field
10075 appropriately. */
10079 }
10080 else
10083 /* If we called start_enum or pushtag above, this information
10084 will already be set up. */
10087 {
10094 }
10097 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10098 of export flag. We want to propagate this because it might
10099 be a friend declaration that pushes a new hidden binding. */
10103 {
10109 {
10112 }
10113 }
10117 {
10121 {
10122 tree attributes
10130 }
10131 }
10133 /* Let's consider the explicit specialization of a member
10134 of a class template specialization that is implicitly instantiated,
10135 e.g.:
10136 template<class T>
10137 struct S
10138 {
10139 template<class U> struct M {}; //#0
10140 };
10142 template<>
10143 template<>
10144 struct S<int>::M<char> //#1
10145 {
10146 int i;
10147 };
10148 [temp.expl.spec]/4 says this is valid.
10150 In this case, when we write:
10151 S<int>::M<char> m;
10153 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10154 the one of #0.
10156 When we encounter #1, we want to store the partial instantiation
10157 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10159 For all cases other than this "explicit specialization of member of a
10160 class template", we just want to store the most general template into
10161 the CLASSTYPE_TI_TEMPLATE of M.
10163 This case of "explicit specialization of member of a class template"
10164 only happens when:
10165 1/ the enclosing class is an instantiation of, and therefore not
10166 the same as, the context of the most general template, and
10167 2/ we aren't looking at the partial instantiation itself, i.e.
10168 the innermost arguments are not the same as the innermost parms of
10169 the most general template.
10171 So it's only when 1/ and 2/ happens that we want to use the partial
10172 instantiation of the member template in lieu of its most general
10173 template. */
10177 /* the enclosing class must be an instantiation... */
10180 {
10184 tree partial_inst_args =
10191 use_partial_inst_tmpl =
10192 /*...and we must not be looking at the partial instantiation
10193 itself. */
10195 partial_inst_args);
10196 }
10199 /* This case is easy; there are no member templates involved. */
10201 else
10202 {
10203 /* This is a full instantiation of a member template. Find
10204 the partial instantiation of which this is an instance. */
10206 /* Temporarily reduce by one the number of levels in the ARGLIST
10207 so as to avoid comparing the last set of arguments. */
10209 /* We don't use COMPLAIN in the following call because this isn't
10210 the immediate context of deduction. For instance, tf_partial
10211 could be set here as we might be at the beginning of template
10212 argument deduction when any explicitly specified template
10213 arguments are substituted into the function type. tf_partial
10214 could lead into trouble because we wouldn't find the partial
10215 instantiation that might have been created outside tf_partial
10216 context, because the levels of template parameters wouldn't
10217 match, because in a tf_partial context, tsubst doesn't reduce
10218 TEMPLATE_PARM_LEVEL. */
10221 /* FOUND is either a proper class type, or an alias
10222 template specialization. In the later case, it's a
10223 TYPE_DECL, resulting from the substituting of arguments
10224 for parameters in the TYPE_DECL of the alias template
10225 done earlier. So be careful while getting the template
10226 of FOUND. */
10228 ? found
10235 {
10236 /* If this partial instantiation is specialized, we want to
10237 use it for hash table lookup. */
10241 }
10242 }
10244 /* Build template info for the new specialization. */
10254 /* Note this use of the partial instantiation so we can check it
10255 later in maybe_process_partial_specialization. */
10263 /* Now that the type has been registered on the instantiations
10264 list, we set up the enumerators. Because the enumeration
10265 constants may involve the enumeration type itself, we make
10266 sure to register the type first, and then create the
10267 constants. That way, doing tsubst_expr for the enumeration
10268 constants won't result in recursive calls here; we'll find
10269 the instantiation and exit above. */
10273 /* If the type makes use of template parameters, the
10274 code that generates debugging information will crash. */
10277 /* Possibly limit visibility based on template args. */
10284 }
10285 }
10287 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10289 tree
10291 {
10295 /* The type of the expression is NULL_TREE since the template-id could refer
10296 to an explicit or partial specialization. */
10298 }
10300 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10302 tree
10304 {
10314 {
10316 {
10317 auto_diagnostic_group d;
10320 }
10322 }
10325 }
10327 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10328 TARGS template args, and instantiate it if it's not dependent. */
10330 tree
10332 tsubst_flags_t complain)
10333 {
10337 {
10340 }
10343 }
10345 /* If the set of template parameters PARMS contains a template parameter
10346 at the given LEVEL and INDEX, then return this parameter. Otherwise
10347 return NULL_TREE. */
10349 static tree
10351 {
10360 /* As in template_parm_to_arg. */
10363 else
10368 }
10370 /* Return the template parameter from PARMS that positionally corresponds
10371 to the template parameter PARM, or else return NULL_TREE. */
10373 static tree
10375 {
10379 }
10381 \f
10382 struct pair_fn_data
10383 {
10384 tree_fn_t fn;
10385 tree_fn_t any_fn;
10387 /* True when we should also visit template parameters that occur in
10388 non-deduced contexts. */
10391 };
10393 /* Called from for_each_template_parm via walk_tree. */
10395 static tree
10397 {
10404 #define WALK_SUBTREE(NODE) \
10405 do \
10406 { \
10407 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10408 pfd->include_nondeduced_p, \
10409 pfd->any_fn); \
10410 if (result) goto out; \
10411 } \
10412 while (0)
10422 {
10426 /* Fall through. */
10432 else
10442 /* Since we're not going to walk subtrees, we have to do this
10443 explicitly here. */
10445 /* Fall through. */
10448 /* Check the return type. */
10451 /* Check the parameter types. Since default arguments are not
10452 instantiated until they are needed, the TYPE_ARG_TYPES may
10453 contain expressions that involve template parameters. But,
10454 no-one should be looking at them yet. And, once they're
10455 instantiated, they don't contain template parameters, so
10456 there's no point in looking at them then, either. */
10457 {
10458 tree parm;
10463 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10464 want walk_tree walking into them itself. */
10466 }
10469 {
10473 }
10489 {
10492 }
10515 /* Record template parameters such as `T' inside `TT<T>'. */
10517 /* Fall through. */
10529 /* A template template parameter is encountered. */
10533 /* Already substituted template template parameter */
10538 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10539 partial instantiation. */
10546 /* If there's no type, then this thing must be some expression
10547 involving template parameters. */
10557 /* These are non-deduced contexts. */
10579 }
10581 #undef WALK_SUBTREE
10583 /* We didn't find any template parameters we liked. */
10584 out:
10586 }
10588 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10589 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10590 call FN with the parameter and the DATA.
10591 If FN returns nonzero, the iteration is terminated, and
10592 for_each_template_parm returns 1. Otherwise, the iteration
10593 continues. If FN never returns a nonzero value, the value
10594 returned by for_each_template_parm is 0. If FN is NULL, it is
10595 considered to be the function which always returns 1.
10597 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10598 parameters that occur in non-deduced contexts. When false, only
10599 visits those template parameters that can be deduced. */
10601 static tree
10605 tree_fn_t any_fn)
10606 {
10608 tree result;
10610 /* Set up. */
10616 /* Walk the tree. (Conceptually, we would like to walk without
10617 duplicates, but for_each_template_parm_r recursively calls
10618 for_each_template_parm, so we would need to reorganize a fair
10619 bit to use walk_tree_without_duplicates, so we keep our own
10620 visited list.) */
10623 else
10626 for_each_template_parm_r,
10630 /* Clean up. */
10632 {
10635 }
10638 }
10640 struct find_template_parameter_info
10641 {
10646 {}
10650 tree parm_list;
10651 tree ctx_parms;
10653 };
10655 /* Appends the declaration of T to the list in DATA. */
10657 static int
10659 {
10662 /* Template parameters declared within the expression are not part of
10663 the parameter mapping. For example, in this concept:
10665 template<typename T>
10666 concept C = requires { <expr> } -> same_as<int>;
10668 the return specifier same_as<int> declares a new decltype parameter
10669 that must not be part of the parameter mapping. The same is true
10670 for generic lambda parameters, lambda template parameters, etc. */
10678 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10679 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10682 /* This template parameter might be an argument to a cached dependent
10683 specalization that was formed earlier inside some other template, in
10684 which case the parameter is not among the ones that are in-scope.
10685 Look in CTX_PARMS to find the corresponding in-scope template
10686 parameter, and use it instead. */
10690 /* Arguments like const T yield parameters like const T. This means that
10691 a template-id like X<T, const T> would yield two distinct parameters:
10692 T and const T. Adjust types to their unqualified versions. */
10698 /* Verify the parameter we found has a valid index. */
10700 {
10706 }
10709 }
10711 /* Ensure that we recursively examine certain terms that are not normally
10712 visited in for_each_template_parm_r. */
10714 static int
10716 {
10719 #define WALK_SUBTREE(NODE) \
10720 do \
10721 { \
10722 for_each_template_parm (NODE, keep_template_parm, data, \
10723 &ftpi->visited, true, \
10724 any_template_parm_r); \
10725 } \
10726 while (0)
10728 /* A mention of a member alias/typedef is a use of all of its template
10729 arguments, including those from the enclosing class, so we don't use
10730 alias_template_specialization_p here. */
10736 {
10738 /* Type constraints of a placeholder type may contain parameters. */
10745 /* Search through references to variable templates. */
10755 /* If T is a member template that shares template parameters with
10756 ctx_parms, we need to mark all those parameters for mapping.
10757 To that end, it should suffice to just walk the DECL_CONTEXT of
10758 the template (assuming the template is not overly general). */
10763 {
10764 /* Look in the parms and body. */
10768 }
10773 /* The conversion-type-id of a conversion operator may be dependent. */
10784 }
10786 /* Keep walking. */
10788 }
10790 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10791 are the template parameters in scope. */
10793 tree
10795 {
10803 }
10805 /* Returns true if T depends on any template parameter. */
10807 bool
10809 {
10813 /* Namespaces can't depend on any template parameters. */
10829 else
10831 }
10833 /* Returns true iff we're processing an incompletely instantiated function
10834 template. Useful instead of processing_template_decl because the latter
10835 is set to 0 during instantiate_non_dependent_expr. */
10837 bool
10839 {
10840 /* Inspect the less volatile cfun->decl instead of current_function_decl;
10841 the latter might get set for e.g. access checking during satisfaction. */
10850 }
10852 /* Returns true if T depends on any template parameter with level LEVEL. */
10854 bool
10856 {
10859 }
10861 /* Returns true if the signature of DECL depends on any template parameter from
10862 its enclosing class. */
10864 static bool
10866 {
10875 {
10878 {
10883 template_parm_outer_level,
10893 }
10894 }
10898 }
10900 /* Returns true if the constraints of DECL depend on any template parameters
10901 from its enclosing scope. */
10903 bool
10905 {
10916 }
10918 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10919 ill-formed translation unit, i.e. a variable or function that isn't
10920 usable in a constant expression. */
10924 {
10930 }
10932 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10933 neglectable and instantiated from within an erroneous instantiation. */
10935 static bool
10937 {
10943 /* Avoid instantiating members of an ill-formed class. */
10944 bool refuse
10949 {
10954 }
10957 {
10958 /* Don't warn about it not being defined. */
10960 tree clone;
10963 }
10965 }
10973 /* We're starting to instantiate D; record the template instantiation context
10974 at LOC for diagnostics and to restore it later. */
10976 bool
10978 {
10982 {
10983 /* Tell error.cc not to try to instantiate any templates. */
10986 "template instantiation depth exceeds maximum of %d"
10988 max_tinst_depth);
10990 }
10992 /* If the current instantiation caused problems, don't let it instantiate
10993 anything else. Do allow deduction substitution and decls usable in
10994 constant expressions. */
10996 {
10997 /* Avoid no_linkage_errors and unused function (and all other)
10998 warnings for this decl. */
11001 }
11003 /* When not -quiet, dump template instantiations other than functions, since
11004 announce_function will take care of those. */
11026 }
11028 /* We're starting substitution of TMPL<ARGS>; record the template
11029 substitution context for diagnostics and to restore it later. */
11031 bool
11033 {
11035 }
11037 /* We're starting to instantiate D; record INPUT_LOCATION and the
11038 template instantiation context for diagnostics and to restore it
11039 later. */
11041 bool
11043 {
11045 }
11047 /* Likewise, but record LOC as the program location. */
11049 bool
11051 {
11054 }
11056 /* We're done instantiating this template; return to the instantiation
11057 context. */
11059 void
11061 {
11062 /* Restore the filename and line number stashed away when we started
11063 this instantiation. */
11067 }
11069 /* We're instantiating a deferred template; restore the template
11070 instantiation context in which the instantiation was requested, which
11071 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11073 static tree
11075 {
11087 }
11089 /* Returns the TINST_LEVEL which gives the original instantiation
11090 context. */
11094 {
11100 }
11102 /* True iff T is a friend function declaration that is not itself a template
11103 and is not defined in a class template. */
11105 bool
11107 {
11110 {
11114 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11117 /* Non-templated friends in a class template are still represented with a
11118 TEMPLATE_DECL; check that its primary template is the befriending
11119 class. Note that DECL_PRIMARY_TEMPLATE is null for
11120 template <class T> friend A<T>::f(); */
11124 }
11125 else
11127 }
11129 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11130 vector of template arguments, as for tsubst.
11132 Returns an appropriate tsubst'd friend declaration. */
11134 static tree
11136 {
11137 tree new_friend;
11142 /* This was a friend declared with an explicit template
11143 argument list, e.g.:
11145 friend void f<>(T);
11147 to indicate that f was a template instantiation, not a new
11148 function declaration. Now, we have to figure out what
11149 instantiation of what template. */
11150 {
11152 tree new_args;
11153 tree tmpl;
11156 /* Friend functions are looked up in the containing namespace scope.
11157 We must enter that scope, to avoid finding member functions of the
11158 current class with same name. */
11172 tsk_none);
11174 }
11180 /* The NEW_FRIEND will look like an instantiation, to the
11181 compiler, but is not an instantiation from the point of view of
11182 the language. For example, we might have had:
11184 template <class T> struct S {
11185 template <class U> friend void f(T, U);
11186 };
11188 Then, in S<int>, template <class U> void f(int, U) is not an
11189 instantiation of anything. */
11193 {
11199 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11200 match in decls_match. */
11205 {
11207 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11209 tf_warning_or_error);
11210 }
11211 }
11213 /* The mangled name for the NEW_FRIEND is incorrect. The function
11214 is not a template instantiation and should not be mangled like
11215 one. Therefore, we forget the mangling here; we'll recompute it
11216 later if we need it. */
11218 {
11221 }
11224 {
11225 tree old_decl;
11226 tree ns;
11228 /* We must save some information from NEW_FRIEND before calling
11229 duplicate decls since that function will free NEW_FRIEND if
11230 possible. */
11234 (new_friend_template_info
11241 {
11242 /* This declaration is a `primary' template. */
11247 }
11249 /* Only define a constrained hidden friend when satisfied. */
11252 /* Inside pushdecl_namespace_level, we will push into the
11253 current namespace. However, the friend function should go
11254 into the namespace of the template. */
11264 {
11265 /* This new friend declaration matched an existing
11266 declaration. For example, given:
11268 template <class T> void f(T);
11269 template <class U> class C {
11270 template <class T> friend void f(T) {}
11271 };
11273 the friend declaration actually provides the definition
11274 of `f', once C has been instantiated for some type. So,
11275 old_decl will be the out-of-class template declaration,
11276 while new_friend is the in-class definition.
11278 But, if `f' was called before this point, the
11279 instantiation of `f' will have DECL_TI_ARGS corresponding
11280 to `T' but not to `U', references to which might appear
11281 in the definition of `f'. Previously, the most general
11282 template for an instantiation of `f' was the out-of-class
11283 version; now it is the in-class version. Therefore, we
11284 run through all specialization of `f', adding to their
11285 DECL_TI_ARGS appropriately. In particular, they need a
11286 new set of outer arguments, corresponding to the
11287 arguments for this class instantiation.
11289 The same situation can arise with something like this:
11291 friend void f(int);
11292 template <class T> class C {
11293 friend void f(T) {}
11294 };
11296 when `C<int>' is instantiated. Now, `f(int)' is defined
11297 in the class. */
11300 /* On the other hand, if the in-class declaration does
11301 *not* provide a definition, then we don't want to alter
11302 existing definitions. We can just leave everything
11303 alone. */
11304 ;
11305 else
11306 {
11310 /* Overwrite whatever template info was there before, if
11311 any, with the new template information pertaining to
11312 the declaration. */
11316 {
11317 /* We should have called reregister_specialization in
11318 duplicate_decls. */
11323 /* Instantiate it if the global has already been used. */
11327 }
11328 else
11329 {
11330 tree t;
11332 /* Indicate that the old function template is a partial
11333 instantiation. */
11341 /* Reassign any specializations already in the hash table
11342 to the new more general template, and add the
11343 additional template args. */
11347 {
11349 spec_entry elt;
11361 register_specialization
11364 }
11366 }
11367 }
11369 /* The information from NEW_FRIEND has been merged into OLD_DECL
11370 by duplicate_decls. */
11372 }
11374 /* We've just introduced a namespace-scope function in the purview
11375 without necessarily having opened the enclosing namespace, so
11376 make sure the namespace is in the purview now too. */
11381 }
11382 else
11383 {
11387 /* In the code
11388 template <class T> class C {
11389 template <class U> friend void C1<U>::f (); // case 1
11390 friend void C2<T>::f (); // case 2
11391 };
11392 we only need to make sure CONTEXT is a complete type for
11393 case 2. To distinguish between the two cases, we note that
11394 CONTEXT of case 1 remains dependent type after tsubst while
11395 this isn't true for case 2. */
11405 {
11407 /* do_friend adds the TEMPLATE_DECL for any member friend
11408 template even if it isn't a member template, i.e.
11409 template <class T> friend A<T>::f();
11410 Look through it in that case. */
11414 /* Check to see that the declaration is really present, and,
11415 possibly obtain an improved declaration. */
11420 }
11421 }
11424 }
11426 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11427 template arguments, as for tsubst.
11429 Returns an appropriate tsubst'd friend type or error_mark_node on
11430 failure. */
11432 static tree
11434 {
11435 tree tmpl;
11438 {
11441 }
11446 else
11447 {
11450 }
11456 {
11457 /* The friend template has already been declared. Just
11458 check to see that the declarations match, and install any new
11459 default parameters. We must tsubst the default parameters,
11460 of course. We only need the innermost template parameters
11461 because that is all that redeclare_class_template will look
11462 at. */
11465 {
11469 tf_warning_or_error);
11475 }
11476 }
11477 else
11478 {
11479 /* The friend template has not already been declared. In this
11480 case, the instantiation of the template class will cause the
11481 injection of this template into the namespace scope. */
11485 {
11486 /* The new TMPL is not an instantiation of anything, so we
11487 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11488 for the new type because that is supposed to be the
11489 corresponding template decl, i.e., TMPL. */
11496 /* Substitute into and set the constraints on the new declaration. */
11498 {
11506 }
11508 /* Inject this template into the enclosing namspace scope. */
11510 }
11511 }
11515 else
11519 }
11521 /* Returns zero if TYPE cannot be completed later due to circularity.
11522 Otherwise returns one. */
11524 static int
11526 {
11536 else
11538 }
11543 /* Instantiate the contract statement. */
11545 static tree
11547 tree in_decl)
11548 {
11554 /* Rebuild the result variable. */
11556 {
11564 /* Make sure the postcondition is valid. */
11570 /* Make the variable available for lookup. */
11572 }
11574 /* Instantiate the condition. If the return type is undeduced, process
11575 the expression as if inside a template to avoid spurious type errors. */
11585 /* And the comment. */
11590 }
11592 /* Update T by instantiating its contract attribute. */
11594 static void
11597 {
11598 /* For non-specializations, adjust the current declaration to the most general
11599 version of in_decl. Because we defer the instantiation of contracts as long
11600 as possible, they are still written in terms of the parameters (and return
11601 type) of the most general template. */
11608 /* Get the contract to be instantiated. */
11611 /* Use the complete set of template arguments for instantiation. The
11612 contract may not have been instantiated and still refer to outer levels
11613 of template parameters. */
11616 /* For member functions, make this available for semantic analysis. */
11620 {
11624 }
11631 /* Rebuild the attribute. */
11633 }
11635 /* Rebuild the attribute list for DECL, substituting into contracts
11636 as needed. */
11638 void
11640 {
11643 {
11646 }
11648 }
11650 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11651 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11653 static tree
11656 {
11659 /* Note that contract attributes are never substituted from this function.
11660 Their instantiation is triggered by regenerate_from_template_decl when
11661 we instantiate the body of the function. */
11669 {
11676 clauses
11680 else
11682 }
11686 {
11697 {
11701 {
11703 {
11711 }
11712 else
11713 {
11717 {
11718 bool allow_string
11730 {
11731 location_t loc
11733 match_loc);
11739 "integer expression or string "
11741 else
11745 }
11748 {
11749 location_t loc
11751 match_loc);
11755 }
11757 }
11758 }
11759 }
11760 }
11762 }
11763 /* If the first attribute argument is an identifier, don't
11764 pass it through tsubst. Attributes like mode, format,
11765 cleanup and several target specific attributes expect it
11766 unmodified. */
11768 {
11769 tree chain
11773 }
11775 {
11776 /* An attribute pack expansion. */
11785 {
11789 }
11791 }
11792 else
11800 }
11802 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11803 unchanged or a new TREE_LIST chain. */
11805 static tree
11808 {
11813 {
11817 }
11821 {
11824 {
11827 {
11833 }
11834 }
11836 }
11839 }
11841 /* Apply any attributes which had to be deferred until instantiation
11842 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11843 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11844 false on error. */
11846 static bool
11849 {
11850 tree t;
11857 {
11861 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11862 to our attributes parameter. */
11864 }
11865 else
11866 {
11868 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11869 lookup_template_class_1, and should be preserved. */
11873 }
11875 /* save_template_attributes puts the dependent attributes at the beginning of
11876 the list; find the non-dependent ones. */
11882 /* Apply any non-dependent attributes. */
11888 /* And then any dependent ones. */
11892 {
11897 {
11900 }
11903 }
11905 /* cplus_decl_attributes can add some attributes implicitly. For templates,
11906 those attributes should have been added already when those templates were
11907 parsed, and shouldn't be added based on from which context they are
11908 first time instantiated. */
11911 optimization_default_node);
11914 NULL);
11920 }
11922 /* The template TMPL is being instantiated with the template arguments TARGS.
11923 Perform the access checks that we deferred when parsing the template. */
11925 static void
11927 {
11937 {
11945 /* Make access check error messages point to the location
11946 of the use of the typedef. */
11950 }
11951 }
11953 tree
11955 {
11959 tree typedecl;
11960 tree pbinfo;
11961 tree base_list;
11963 tree fn_context;
11972 /* Figure out which template is being instantiated. */
11976 /* Mark the type as in the process of being defined. */
11979 /* We may be in the middle of deferred access check. Disable
11980 it now. */
11983 /* Determine what specialization of the original template to
11984 instantiate. */
11989 {
11990 /* This TYPE is actually an instantiation of a partial
11991 specialization. We replace the innermost set of ARGS with
11992 the arguments appropriate for substitution. For example,
11993 given:
11995 template <class T> struct S {};
11996 template <class T> struct S<T*> {};
11998 and supposing that we are instantiating S<int*>, ARGS will
11999 presently be {int*} -- but we need {int}. */
12002 }
12003 else
12004 {
12007 }
12009 /* If the template we're instantiating is incomplete, then clearly
12010 there's nothing we can do. */
12012 {
12013 /* We can try again later. */
12016 }
12018 /* If we've recursively instantiated too many templates, stop. */
12026 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12031 else
12032 {
12035 }
12036 /* Use #pragma pack from the template context. */
12042 /* Set the input location to the most specialized template definition.
12043 This is needed if tsubsting causes an error. */
12057 {
12060 /* Adjust visibility for template arguments. */
12062 }
12068 /* We should never instantiate a nested class before its enclosing
12069 class; we need to look up the nested class by name before we can
12070 instantiate it, and that lookup should instantiate the enclosing
12071 class. */
12076 /* Defer access checking while we substitute into the types named in
12077 the base-clause. */
12080 {
12081 tree pbase_binfo;
12084 /* Substitute into each of the bases to determine the actual
12085 basetypes. */
12087 {
12088 tree base;
12094 {
12095 expanded_bases =
12102 }
12105 {
12107 /* Extract the already-expanded base class. */
12109 else
12110 /* Substitute to figure out the base class. */
12112 NULL_TREE);
12120 }
12121 }
12123 /* The list is now in reverse order; correct that. */
12125 }
12126 /* Now call xref_basetypes to set up all the base-class
12127 information. */
12135 /* Now that our base classes are set up, enter the scope of the
12136 class, so that name lookups into base classes, etc. will work
12137 correctly. This is precisely analogous to what we do in
12138 begin_class_definition when defining an ordinary non-template
12139 class, except we also need to push the enclosing classes. */
12142 /* Now check accessibility of the types named in its base-clause,
12143 relative to the scope of the class. */
12146 /* A vector to hold members marked with attribute used. */
12149 /* Now members are processed in the order of declaration. */
12152 {
12156 {
12158 {
12160 /* A closure type for a lambda in an NSDMI or default argument.
12161 Ignore it; it will be regenerated when needed. */
12168 /* If the member is a class template, then -- even after
12169 substitution -- there may be dependent types in the
12170 template argument list for the class. We increment
12171 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
12172 that function will assume that no types are dependent
12173 when outside of a template. */
12183 {
12187 /* Unfortunately, lookup_template_class sets
12188 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
12189 instantiation (i.e., for the type of a member
12190 template class nested within a template class.)
12191 This behavior is required for
12192 maybe_process_partial_specialization to work
12193 correctly, but is not accurate in this case;
12194 the TAG is not an instantiation of anything.
12195 (The corresponding TEMPLATE_DECL is an
12196 instantiation, but the TYPE is not.) */
12199 /* Now, install the tag. We don't use pushtag
12200 because that does too much work -- creating an
12201 implicit typedef, which we've already done. */
12206 }
12207 }
12209 {
12210 tree r;
12220 /* Instantiate members marked with attribute used. */
12226 }
12229 /* A closure type for a lambda in an NSDMI or default argument.
12231 else
12232 {
12233 /* Build new TYPE_FIELDS. */
12237 {
12238 tree r;
12243 /* The file and line for this declaration, to
12244 assist in error message reporting. Since we
12245 called push_tinst_level above, we don't need to
12246 restore these. */
12256 {
12257 /* A capture pack became multiple fields. */
12260 }
12263 {
12267 {
12268 /* In [temp.inst]:
12270 [t]he initialization (and any associated
12271 side-effects) of a static data member does
12272 not occur unless the static data member is
12273 itself used in a way that requires the
12274 definition of the static data member to
12275 exist.
12277 Therefore, we do not substitute into the
12278 initialized for the static data member here. */
12279 finish_static_data_member_decl
12285 /* Instantiate members marked with attribute used. */
12288 }
12290 {
12291 /* Determine whether R has a valid type and can be
12292 completed later. If R is invalid, then its type
12293 is replaced by error_mark_node. */
12299 {
12300 /* If R's type couldn't be completed and
12301 it isn't a flexible array member (whose
12302 type is incomplete by definition) give
12303 an error. */
12306 }
12311 {
12314 }
12318 }
12320 /* If it is a TYPE_DECL for a class-scoped
12321 ENUMERAL_TYPE, such a thing will already have
12322 been added to the field list by tsubst_enum
12323 in finish_member_declaration case above. */
12327 {
12330 }
12331 }
12332 }
12333 }
12334 }
12335 else
12336 {
12339 {
12340 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12344 {
12345 /* template <class T> friend class C; */
12347 }
12349 {
12350 /* template <class T> friend class C::D; */
12355 }
12358 {
12359 /* This could be either
12361 friend class T::C;
12363 when dependent_type_p is false or
12365 template <class U> friend class T::C;
12367 otherwise. */
12368 /* Bump processing_template_decl in case this is something like
12369 template <class T> friend struct A<T>::B. */
12374 }
12376 /* friend class C<T>; */
12380 /* Otherwise it's
12382 friend class C;
12384 where C is already declared or
12386 friend class C<int>;
12388 We don't have to do anything in these cases. */
12392 }
12393 else
12394 {
12395 /* Build new DECL_FRIENDLIST. */
12396 tree r;
12398 /* The file and line for this declaration, to
12399 assist in error message reporting. Since we
12400 called push_tinst_level above, we don't need to
12401 restore these. */
12405 {
12408 }
12413 {
12416 }
12417 }
12418 }
12419 }
12422 {
12423 /* Restore these before substituting into the lambda capture
12424 initializers. */
12427 }
12429 /* Set the file and line number information to whatever is given for
12430 the class itself. This puts error messages involving generated
12431 implicit functions at a predictable point, and the same point
12432 that would be used for non-template classes. */
12439 /* Remember if instantiating this class ran into errors, so we can avoid
12440 instantiating member functions in limit_bad_template_recursion. We set
12441 this flag even if the problem was in another instantiation triggered by
12442 this one, as that will likely also cause trouble for member functions. */
12446 /* We don't instantiate default arguments for member functions. 14.7.1:
12448 The implicit instantiation of a class template specialization causes
12449 the implicit instantiation of the declarations, but not of the
12450 definitions or default arguments, of the class member functions,
12451 member classes, static data members and member templates.... */
12456 /* Now that we've gone through all the members, instantiate those
12457 marked with attribute used. We must do this in the context of
12458 the class -- not the context we pushed from, as that might be
12459 inside a template and change the behaviour of mark_used. */
12469 /* The vtable for a template class can be emitted in any translation
12470 unit in which the class is instantiated. When there is no key
12471 method, however, finish_struct_1 will already have added TYPE to
12472 the keyed_classes. */
12477 }
12479 tree
12481 {
12482 tree r;
12488 else
12489 {
12495 }
12498 }
12500 /* Given a function parameter pack TMPL_PARM and some function parameters
12501 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12502 and set *SPEC_P to point at the next point in the list. */
12504 tree
12506 {
12507 /* Collect all of the extra "packed" parameters into an
12508 argument pack. */
12509 tree argpack;
12520 {
12521 /* The instantiation is still a parameter pack; don't wrap it in a
12522 NONTYPE_ARGUMENT_PACK. */
12525 }
12526 else
12527 {
12528 /* Fill in PARMVEC with all of the parameters. */
12532 {
12538 }
12540 /* Build the argument packs. */
12542 }
12546 }
12548 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12549 NONTYPE_ARGUMENT_PACK. */
12551 static tree
12553 {
12555 }
12557 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12558 pack expansion with no extra args, 2 if it has extra args, or 0
12559 if it is not a pack expansion. */
12561 static int
12563 {
12565 /* We're being called before this happens in tsubst_pack_expansion. */
12572 /* A decl pack is itself an expansion. */
12579 }
12582 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12584 static tree
12586 {
12593 }
12595 /* This is a subroutine of tsubst_pack_expansion.
12597 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12598 mechanism to store the (non complete list of) arguments of the
12599 substitution and return a non substituted pack expansion, in order
12600 to wait for when we have enough arguments to really perform the
12601 substitution. */
12603 static bool
12605 tree parm_packs,
12608 {
12613 /* If one pack has an expansion and another pack has a normal
12614 argument or if one pack has an empty argument and an another
12615 one hasn't then tsubst_pack_expansion cannot perform the
12616 substitution and need to fall back on the
12617 PACK_EXPANSION_EXTRA mechanism. */
12621 {
12622 /* If all the actual packs are pack expansions, we can still
12623 subsitute directly. */
12625 {
12635 }
12637 }
12640 {
12644 parm_pack;
12646 {
12651 /* We can't substitute a pack expansion with extra args into
12652 our pattern. */
12656 else
12658 }
12661 {
12664 }
12665 }
12667 }
12669 /* [temp.variadic]/6 says that:
12671 The instantiation of a pack expansion [...]
12672 produces a list E1,E2, ..., En, where N is the number of elements
12673 in the pack expansion parameters.
12675 This subroutine of tsubst_pack_expansion produces one of these Ei.
12677 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12678 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12679 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12680 INDEX is the index 'i' of the element Ei to produce. ARGS,
12681 COMPLAIN, and IN_DECL are the same parameters as for the
12682 tsubst_pack_expansion function.
12684 The function returns the resulting Ei upon successful completion,
12685 or error_mark_node.
12687 Note that this function possibly modifies the ARGS parameter, so
12688 it's the responsibility of the caller to restore it. */
12690 static tree
12692 tree parm_packs,
12694 tree args /* This parm gets
12696 tsubst_flags_t complain,
12697 tree in_decl)
12698 {
12699 tree t;
12702 /* For each parameter pack, change the substitution of the parameter
12703 pack to the ith argument in its argument pack, then expand the
12704 pattern. */
12706 {
12711 ith_elem_is_expansion |=
12714 /* Select the Ith argument from the pack. */
12718 {
12720 {
12725 }
12726 else
12728 }
12729 else
12730 {
12735 {
12737 /* Update the corresponding argument. */
12739 }
12740 else
12741 /* Re-use the ARGUMENT_PACK_SELECT. */
12743 }
12745 }
12747 /* Substitute into the PATTERN with the (possibly altered)
12748 arguments. */
12750 /* Expanding a fixed parameter pack from
12751 coerce_template_parameter_pack. */
12757 else
12758 {
12761 /* When expanding the fake auto... pack expansion from add_capture, we
12762 need to mark that the expansion is no longer a pack. */
12764 }
12766 /* If the Ith argument pack element is a pack expansion, then
12767 the Ith element resulting from the substituting is going to
12768 be a pack expansion as well. */
12773 }
12775 /* When the unexpanded parameter pack in a fold expression expands to an empty
12776 sequence, the value of the expression is as follows; the program is
12777 ill-formed if the operator is not listed in this table.
12779 && true
12780 || false
12781 , void() */
12783 tree
12785 {
12789 {
12798 }
12804 }
12806 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12807 form an expression that combines the two terms using the
12808 operator of T. */
12810 static tree
12812 {
12817 // Handle compound assignment operators.
12824 {
12833 complain);
12834 }
12835 }
12837 /* Substitute ARGS into the pack of a fold expression T. */
12841 {
12843 }
12845 /* Substitute ARGS into the pack of a fold expression T. */
12849 {
12851 }
12853 /* Expand a PACK of arguments into a grouped as left fold.
12854 Given a pack containing elements A0, A1, ..., An and an
12855 operator @, this builds the expression:
12857 ((A0 @ A1) @ A2) ... @ An
12859 Note that PACK must not be empty.
12861 The operator is defined by the original fold expression T. */
12863 static tree
12865 {
12868 {
12871 }
12873 }
12875 /* Substitute into a unary left fold expression. */
12877 static tree
12879 tree in_decl)
12880 {
12885 {
12889 }
12892 else
12894 }
12896 /* Substitute into a binary left fold expression.
12898 Do ths by building a single (non-empty) vector of argumnts and
12899 building the expression from those elements. */
12901 static tree
12903 tree in_decl)
12904 {
12913 {
12918 }
12926 }
12928 /* Expand a PACK of arguments into a grouped as right fold.
12929 Given a pack containing elementns A0, A1, ..., and an
12930 operator @, this builds the expression:
12932 A0@ ... (An-2 @ (An-1 @ An))
12934 Note that PACK must not be empty.
12936 The operator is defined by the original fold expression T. */
12938 tree
12940 {
12941 // Build the expression.
12945 {
12948 }
12950 }
12952 /* Substitute into a unary right fold expression. */
12954 static tree
12956 tree in_decl)
12957 {
12962 {
12966 }
12969 else
12971 }
12973 /* Substitute into a binary right fold expression.
12975 Do ths by building a single (non-empty) vector of arguments and
12976 building the expression from those elements. */
12978 static tree
12980 tree in_decl)
12981 {
12990 {
12995 }
13004 }
13006 /* Walk through the pattern of a pack expansion, adding everything in
13007 local_specializations to a list. */
13009 class el_data
13010 {
13012 /* Set of variables declared within the pattern. */
13014 /* Set of AST nodes that have been visited by the traversal. */
13016 /* List of local_specializations used within the pattern. */
13017 tree extra;
13018 tsubst_flags_t complain;
13022 };
13023 static tree
13025 {
13031 /* Remember local typedefs (85214). */
13035 {
13041 {
13044 decl2
13050 {
13053 }
13054 }
13055 }
13057 {
13058 /* Since we defer implicit capture, look in the parms and body. */
13064 }
13066 {
13068 /* Don't mess with variables declared within the pattern. */
13071 {
13072 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13075 {
13081 }
13083 {
13084 /* Handle lambda capture here, since we aren't doing any
13085 substitution now, and so tsubst_copy won't call
13086 process_outer_var_ref. */
13090 {
13096 {
13097 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13098 proxies. */
13100 {
13105 }
13107 }
13108 }
13109 }
13110 }
13114 }
13116 }
13117 static tree
13119 {
13123 }
13125 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13126 for use in PACK_EXPANSION_EXTRA_ARGS. */
13128 tree
13130 {
13131 /* Make a copy of the extra arguments so that they won't get changed
13132 out from under us. */
13138 }
13140 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13141 normal template args to ARGS. */
13143 tree
13145 {
13147 {
13149 {
13150 /* The partial instantiation involved local declarations collected in
13151 extract_local_specs; map from the general template to our local
13152 context. */
13158 /* else inst is already a full instantiation of the pack. */
13160 }
13163 }
13165 {
13166 /* This can happen after dependent substitution into a
13167 requires-expr or a lambda that uses constexpr if. */
13170 }
13171 else
13174 }
13176 /* Substitute ARGS into T, which is an pack expansion
13177 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13178 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13179 (if only a partial substitution could be performed) or
13180 ERROR_MARK_NODE if there was an error. */
13181 tree
13183 tree in_decl)
13184 {
13185 tree pattern;
13189 tree result;
13196 /* Add in any args remembered from an earlier partial instantiation. */
13201 /* Determine the argument packs that will instantiate the parameter
13202 packs used in the expansion expression. While we're at it,
13203 compute the number of arguments to be expanded and make sure it
13204 is consistent. */
13207 {
13214 {
13219 in_decl),
13220 complain);
13221 else
13224 complain);
13225 }
13227 {
13229 {
13232 parm_pack);
13234 }
13237 }
13239 {
13240 /* We know we have correct local_specializations if this
13241 expansion is at function scope, or if we're dealing with a
13242 local parameter in a requires expression; for the latter,
13243 tsubst_requires_expr set it up appropriately. */
13246 else
13247 /* We can't rely on local_specializations for a parameter
13248 name used later in a function declaration (such as in a
13249 late-specified return type). Even if it exists, it might
13250 have the wrong value for a recursive call. */
13254 {
13255 /* This parameter pack was used in an unevaluated context. Just
13256 make a dummy decl, since it's only used for its type. */
13261 /* Partial instantiation of the parm_pack, we can't build
13262 up an argument pack yet. */
13264 else
13266 }
13268 /* This argument pack isn't fully instantiated yet. */
13270 }
13272 {
13276 }
13277 else
13278 {
13287 }
13294 /* This can only happen if we forget to expand an argument
13295 pack somewhere else. Just return an error, silently. */
13296 {
13300 }
13303 {
13307 /* Don't bother trying to do a partial substitution with
13308 incomplete packs; we'll try again after deduction. */
13315 {
13320 pattern);
13321 else
13323 pattern);
13325 }
13327 /* Keep track of the parameter packs and their corresponding
13328 argument packs. */
13331 }
13332 else
13333 {
13334 /* We can't substitute for this parameter pack. We use a flag as
13335 well as the missing_level counter because function parameter
13336 packs don't have a level. */
13339 }
13340 }
13342 /* If the expansion is just T..., return the matching argument pack, unless
13343 we need to call convert_from_reference on all the elements. This is an
13344 important optimization; see c++/68422. */
13347 {
13350 /* If the argument pack is a single pack expansion, pull it out. */
13355 /* Types need no adjustment, nor does sizeof..., and if we still have
13356 some pack expansion args we won't do anything yet. */
13361 /* Also optimize expression pack expansions if we can tell that the
13362 elements won't have reference type. */
13368 /* Otherwise use the normal path so we get convert_from_reference. */
13369 }
13371 /* We cannot expand this expansion expression, because we don't have
13372 all of the argument packs we need. */
13374 {
13375 /* We got some full packs, but we can't substitute them in until we
13376 have values for all the packs. So remember these until then. */
13382 }
13384 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13385 type, so create our own local specializations map; the current map is
13386 either NULL or (in the case of recursive unification) might have
13387 bindings that we don't want to use or alter. */
13392 {
13393 /* There were no real arguments, we're just replacing a parameter
13394 pack with another version of itself. Substitute into the
13395 pattern and return a PACK_EXPANSION_*. The caller will need to
13396 deal with that. */
13399 else
13405 {
13406 /* This is a fake auto... pack expansion created in add_capture with
13407 _PACKS that don't appear in the pattern. Copy one over. */
13414 }
13416 }
13420 /* For each argument in each argument pack, substitute into the
13421 pattern. */
13425 {
13427 i,
13429 in_decl);
13432 {
13435 }
13436 }
13438 /* Update ARGS to restore the substitution from parameter packs to
13439 their argument packs. */
13441 {
13448 else
13449 {
13457 /* Update the corresponding argument. */
13461 else
13463 }
13464 }
13466 /* If the dependent pack arguments were such that we end up with only a
13467 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13473 }
13475 /* Make an argument pack out of the TREE_VEC VEC. */
13477 static tree
13479 {
13480 tree pack;
13484 else
13485 {
13488 }
13491 }
13493 /* Return an exact copy of template args T that can be modified
13494 independently. */
13496 static tree
13498 {
13506 {
13511 }
13517 }
13519 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13521 tree
13523 tree in_decl)
13524 {
13525 /* This flag is used only during deduction, and we don't expect to
13526 substitute such ARGUMENT_PACKs. */
13529 /* Substitute into each of the arguments. */
13538 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13539 template parameter, we might be able to avoid allocating a new
13540 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13541 if the substituted result is identical to it. */
13543 {
13550 {
13553 }
13554 }
13556 tree new_arg;
13558 {
13561 }
13562 else
13563 {
13566 }
13569 }
13571 /* Substitute ARGS into the vector or list of template arguments T. */
13573 tree
13575 {
13579 /* In "sizeof(X<I>)" we need to evaluate "I". */
13580 cp_evaluated ev;
13586 /* True iff the substituted result is identical to T. */
13590 {
13592 tree new_arg;
13599 {
13600 /* Substitute into an expansion expression. */
13604 /* Add to the expanded length adjustment the number of
13605 expanded arguments. We subtract one from this
13606 measurement, because the argument pack expression
13607 itself is already counted as 1 in
13608 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13609 the argument pack is empty. */
13611 }
13614 else
13623 }
13630 /* If ARGS and T are both multi-level, the substituted result may be
13631 identical to ARGS. */
13636 /* If T appears to be a vector of generic template arguments, the
13637 substituted result may be identical to the corresponding level
13638 from ARGS. */
13640 {
13645 }
13647 /* If the substituted result is identical to MAYBE_REUSE, return
13648 it and avoid allocating a new TREE_VEC, as an optimization. */
13654 /* If T consists of only a pack expansion for which substitution yielded
13655 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13656 of effectively making a copy. */
13662 /* Make space for the expanded arguments coming from template
13663 argument packs. */
13665 /* T can contain TREE_VECs. That happens if T contains the
13666 arguments for a member template.
13667 In that case each TREE_VEC in T represents a level of template
13668 arguments, and T won't carry any non defaulted argument count.
13669 It will rather be the nested TREE_VECs that will carry one.
13670 In other words, T carries a non defaulted argument count only
13671 if it doesn't contain any nested TREE_VEC. */
13673 {
13677 }
13681 {
13686 {
13687 /* Now expand the template argument pack "in place". */
13690 }
13691 else
13692 {
13694 out++;
13695 }
13696 }
13700 }
13702 /* Substitute ARGS into one level PARMS of template parameters. */
13704 static tree
13706 {
13713 {
13721 }
13724 }
13726 /* Return the result of substituting ARGS into the template parameters
13727 given by PARMS. If there are m levels of ARGS and m + n levels of
13728 PARMS, then the result will contain n levels of PARMS. For
13729 example, if PARMS is `template <class T> template <class U>
13730 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13731 result will be `template <int*, double, class V>'. */
13733 static tree
13735 {
13739 /* When substituting into a template, we must set
13740 PROCESSING_TEMPLATE_DECL as the template parameters may be
13741 dependent if they are based on one-another, and the dependency
13742 predicates are short-circuit outside of templates. */
13749 {
13758 }
13763 }
13765 /* Return the result of substituting ARGS into one template parameter
13766 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13767 parameter and which TREE_PURPOSE is the default argument of the
13768 template parameter. */
13770 static tree
13772 {
13795 }
13797 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13798 parameter in PARMS for sake of declaration matching. */
13800 static void
13802 tsubst_flags_t complain)
13803 {
13806 {
13812 }
13814 }
13816 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13817 type T. If T is not an aggregate or enumeration type, it is
13818 handled as if by tsubst. IN_DECL is as for tsubst. If
13819 ENTERING_SCOPE is nonzero, T is the context for a template which
13820 we are presently tsubst'ing. Return the substituted value. */
13822 static tree
13824 tree args,
13825 tsubst_flags_t complain,
13826 tree in_decl,
13828 {
13832 /* Handle typedefs via tsubst so that they get consistently reused. */
13834 {
13839 /* The effect of entering_scope is that for a dependent specialization
13840 A<T>, lookup_template_class prefers to return A's primary template
13841 type instead of the implicit instantiation. So when entering_scope,
13842 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
13843 taking advantage of the fact that lookup_template_class links the two
13844 types by setting TYPE_CANONICAL of the latter to the former. */
13852 }
13855 {
13863 }
13864 }
13866 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
13867 and ENUMERAL_TYPE cases of tsubst. */
13869 static tree
13871 tree args,
13872 tsubst_flags_t complain,
13873 tree in_decl,
13875 {
13877 {
13878 tree argvec;
13879 tree r;
13881 /* Figure out what arguments are appropriate for the
13882 type we are trying to find. For example, given:
13884 template <class T> struct S;
13885 template <class T, class U> void f(T, U) { S<U> su; }
13887 and supposing that we are instantiating f<int, double>,
13888 then our ARGS will be {int, double}, but, when looking up
13889 S we only want {double}. */
13894 else
13895 {
13899 }
13902 }
13903 else
13904 /* This is not a template type, so there's nothing to do. */
13906 }
13908 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
13909 indexed in reverse order of the parameters. */
13913 /* Return a reference to the vec* of defarg insts for FN. */
13917 {
13921 tree_vec_map **slot
13924 {
13927 }
13929 }
13931 /* Substitute into the default argument ARG (a default argument for
13932 FN), which has the indicated TYPE. */
13934 tree
13936 tsubst_flags_t complain)
13937 {
13940 /* This can happen in invalid code. */
13944 /* Shortcut {}. */
13959 /* Remember the location of the pointer to the vec rather than the location
13960 of the particular element, in case the vec grows in tsubst_expr. */
13962 /* Index in reverse order to avoid allocating space for initial parameters
13963 that don't have default arguments. */
13970 /* This default argument came from a template. Instantiate the
13971 default argument here, not in tsubst. In the case of
13972 something like:
13974 template <class T>
13975 struct S {
13976 static T t();
13977 void f(T = t());
13978 };
13980 we must be careful to do name lookup in the scope of S<T>,
13981 rather than in the current class. */
13985 /* So in_immediate_context knows this is a default argument. */
13989 /* The default argument expression may cause implicitly defined
13990 member functions to be synthesized, which will result in garbage
13991 collection. We must treat this situation as if we were within
13992 the body of function so as to avoid collecting live data on the
13993 stack. */
14000 /* Make sure the default argument is reasonable. */
14017 }
14019 /* Substitute into all the default arguments for FN. */
14021 static void
14023 {
14024 tree arg;
14025 tree tmpl_args;
14029 /* If this function is not yet instantiated, we certainly don't need
14030 its default arguments. */
14033 /* Don't do this again for clones. */
14039 arg;
14045 complain);
14046 }
14048 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14051 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14053 void
14055 {
14060 }
14062 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14064 tree
14066 {
14068 }
14070 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14071 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14072 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14073 identical to T. */
14075 static tree
14078 {
14081 tree new_type;
14083 {
14086 }
14087 else
14088 {
14090 /* Don't pick up extra function qualifiers from the basetype. */
14093 {
14094 /* [temp.deduct]
14096 Type deduction may fail for any of the following
14097 reasons:
14099 -- Attempting to create "pointer to member of T" when T
14100 is not a class type. */
14103 r);
14105 }
14109 }
14115 }
14117 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14118 each of its formal parameters. If there is a disagreement then rebuild
14119 DECL's function type according to its formal parameter types, as part of a
14120 resolution for Core issues 1001/1322. */
14122 static void
14124 {
14127 {
14130 {
14134 {
14137 }
14141 }
14142 }
14153 {
14158 }
14160 {
14170 }
14178 }
14180 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14182 static tree
14184 tree lambda_fntype)
14185 {
14190 /* Nobody should be tsubst'ing into non-template functions. */
14195 {
14198 }
14200 {
14201 /* If T is not dependent, just return it. */
14206 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14210 /* Calculate the most general template of which R is a
14211 specialization. */
14214 /* We're substituting a lambda function under tsubst_lambda_expr but not
14215 directly from it; find the matching function we're already inside.
14216 But don't do this if T is a generic lambda with a single level of
14217 template parms, as in that case we're doing a normal instantiation. */
14223 /* Calculate the complete set of arguments used to
14224 specialize R. */
14226 (DECL_TEMPLATE_RESULT
14232 /* Check to see if we already have this specialization. */
14234 {
14237 /* The spec for these args might be a partial instantiation of the
14238 template, but here what we want is the FUNCTION_DECL. */
14240 }
14241 }
14242 else
14243 {
14244 /* This special case arises when we have something like this:
14246 template <class T> struct S {
14247 friend void f<int>(int, double);
14248 };
14250 Here, the DECL_TI_TEMPLATE for the friend declaration
14251 will be an IDENTIFIER_NODE. We are being called from
14252 tsubst_friend_function, and we want only to create a
14253 new decl (R) with appropriate types so that we can call
14254 determine_specialization. */
14255 friend_case:
14258 }
14275 /* If we hit excessive deduction depth, the type is bogus even if
14276 it isn't error_mark_node, so don't build a decl. */
14280 /* We do NOT check for matching decls pushed separately at this
14281 point, as they may not represent instantiations of this
14282 template, and in any case are considered separate under the
14283 discrete model. */
14287 /* Clear out the mangled name and RTL for the instantiation. */
14290 /* Leave DECL_INITIAL set on deleted instantiations. */
14296 /* Handle explicit(dependent-expr). */
14298 {
14306 else
14307 {
14310 }
14311 }
14313 /* OpenMP UDRs have the only argument a reference to the declared
14314 type. We want to diagnose if the declared type is a reference,
14315 which is invalid, but as references to references are usually
14316 quietly merged, diagnose it here. */
14318 {
14319 tree argtype
14324 "reference type %qT in "
14328 argtype);
14329 }
14332 /* Type-conversion operator. Reconstruct the name, in
14333 case it's the name of one of the template's parameters. */
14343 {
14348 }
14357 /* If this is an instantiation of a function with internal
14358 linkage, we already know what object file linkage will be
14359 assigned to the instantiation. */
14368 /* We'll re-clone as appropriate in instantiate_template. */
14371 /* If we aren't complaining now, return on error before we register
14372 the specialization so that we'll complain eventually. */
14378 /* Associate the constraints directly with the instantiation. We
14379 don't substitute through the constraints; that's only done when
14380 they are checked. */
14393 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14394 this in the special friend case mentioned above where
14395 GEN_TMPL is NULL. */
14397 {
14402 tree new_r
14405 /* We instantiated this while substituting into
14406 the type earlier (template/friend54.C). */
14409 /* We're not supposed to instantiate default arguments
14410 until they are called, for a template. But, for a
14411 declaration like:
14413 template <class T> void f ()
14414 { extern void g(int i = T()); }
14416 we should do the substitution when the template is
14417 instantiated. We handle the member function case in
14418 instantiate_class_template since the default arguments
14419 might refer to other members of the class. */
14424 }
14426 {
14429 }
14430 else
14433 /* Copy the list of befriending classes. */
14437 {
14441 }
14444 {
14448 /* If this is an instantiation of a member template, clone it.
14449 If it isn't, that'll be handled by
14450 clone_constructors_and_destructors. */
14453 }
14459 /* Possibly limit visibility based on template args. */
14462 {
14466 }
14478 }
14480 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14482 static tree
14484 tree lambda_fntype)
14485 {
14486 /* We can get here when processing a member function template,
14487 member class template, or template template parameter. */
14490 tree spec;
14491 tree tmpl_args;
14492 tree full_args;
14493 tree r;
14497 {
14498 /* Template template parameter is treated here. */
14502 /* If we get a real template back, return it. This can happen in
14503 the context of most_specialized_partial_spec. */
14506 else
14507 /* The new TEMPLATE_DECL was built in
14508 reduce_template_parm_level. */
14511 }
14514 {
14515 /* We might already have an instance of this template.
14516 The ARGS are for the surrounding class type, so the
14517 full args contain the tsubst'd args for the context,
14518 plus the innermost args from the template decl. */
14522 /* Because this is a template, the arguments will still be
14523 dependent, even after substitution. If
14524 PROCESSING_TEMPLATE_DECL is not set, the dependency
14525 predicates will short-circuit. */
14533 /* If this is a default template template argument,
14534 tsubst might not have changed anything. */
14541 {
14543 /* Type partial instantiations are stored as the type by
14544 lookup_template_class_1, not here as the template. */
14547 }
14548 }
14550 /* Make a new template decl. It will be similar to the
14551 original, but will record the current template arguments.
14552 We also create a new function declaration, which is just
14553 like the old one, but points to this new template, rather
14554 than the old one. */
14559 // Build new template info linking to the original template decl.
14561 {
14564 }
14565 else
14568 /* The template parameters for this new template are all the
14569 template parameters for the old template, except the
14570 outermost level of parameters. */
14573 = current_template_parms
14575 complain);
14582 else
14583 {
14585 {
14588 }
14592 else
14594 }
14600 {
14601 /* For a partial specialization, we need to keep pointing to
14602 the primary template. */
14608 }
14610 {
14613 }
14614 else
14615 {
14618 }
14625 {
14626 /* Propagate module information from the decl. */
14629 /* If this is a constrained template, the above tsubst of
14630 inner can find the unconstrained template, which may have
14631 come from an import. This is ok, because we don't
14632 register this instantiation (see below). */
14634 || (TEMPLATE_PARMS_CONSTRAINTS
14636 }
14645 /* Record this non-type partial instantiation. */
14651 }
14653 /* True if FN is the op() for a lambda in an uninstantiated template. */
14655 bool
14657 {
14662 }
14664 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14665 which the above is true. */
14667 bool
14669 {
14675 }
14677 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14678 If T is not a regenerated LAMBDA_EXPR, return T. */
14680 tree
14682 {
14686 }
14688 /* Return the set of template arguments used to regenerate the lambda T
14689 from its most general lambda. */
14691 tree
14693 {
14699 else
14701 }
14703 /* We're instantiating a variable from template function TCTX. Return the
14704 corresponding current enclosing scope. We can match them up using
14705 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14706 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14707 the template definition in regenerate_decl_from_template. */
14709 static tree
14711 {
14714 /* We shouldn't ever need to do this for other artificial functions. */
14721 }
14723 /* Substitute the ARGS into the T, which is a _DECL. Return the
14724 result of the substitution. Issue error and warning messages under
14725 control of COMPLAIN. */
14727 static tree
14729 {
14730 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14731 location_t saved_loc;
14736 /* Set the filename and linenumber to improve error-reporting. */
14741 {
14751 {
14759 {
14760 /* If there is a local specialization that isn't a
14761 parameter pack, it means that we're doing a "simple"
14762 substitution from inside tsubst_pack_expansion. Just
14763 return the local specialization (which will be a single
14764 parm). */
14771 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14772 the parameters in this function parameter pack. */
14776 {
14779 /* Zero-length parameter packs are boring. Just substitute
14780 into the chain. */
14784 }
14785 else
14786 {
14787 /* All we did was update the type. Make a note of that. */
14790 }
14791 }
14793 /* Loop through all of the parameters we'll build. When T is
14794 a function parameter pack, LEN is the number of expanded
14795 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14798 {
14805 /* We're on the Ith parameter of the function parameter
14806 pack. */
14807 {
14808 /* Get the Ith type. */
14811 /* Rename the parameter to include the index. */
14814 }
14816 /* We're dealing with a normal parameter. */
14824 {
14827 else
14830 }
14841 /* Keep track of the first new parameter we
14842 generate. That's what will be returned to the
14843 caller. */
14847 /* Build a proper chain of parameters when substituting
14848 into a function parameter pack. */
14851 }
14853 /* If cp_unevaluated_operand is set, we're just looking for a
14854 single dummy parameter, so don't keep going. */
14859 /* FIRST_R contains the start of the chain we've built. */
14861 }
14865 {
14872 {
14873 /* This field is a lambda capture pack. Return a TREE_VEC of
14874 the expanded fields to instantiate_class_template_1. */
14878 {
14881 }
14882 else
14883 {
14884 /* All we did was update the type. Make a note of that. */
14887 }
14888 }
14891 {
14894 {
14898 }
14908 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14909 number of bits. */
14914 {
14915 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14916 NSDMI in perform_member_init. Still set DECL_INITIAL
14917 so that we know there is one. */
14922 }
14923 /* We don't have to set DECL_CONTEXT here; it is set by
14924 finish_member_declaration. */
14933 }
14937 }
14941 /* We reach here only for member using decls. We also need to check
14942 uses_template_parms because DECL_DEPENDENT_P is not set for a
14943 using-declaration that designates a member of the current
14944 instantiation (c++/53549). */
14947 {
14951 {
14956 {
14960 {
14963 }
14964 else
14965 {
14968 }
14970 }
14971 }
14972 else
14973 {
14979 else
14980 {
14983 }
14984 }
14985 }
14986 else
14987 {
14990 }
14995 {
15006 {
15007 /* If this is the canonical decl, we don't have to
15008 mess with instantiations, and often we can't (for
15009 typename, template type parms and such). Note that
15010 TYPE_NAME is not correct for the above test if
15011 we've copied the type for a typedef. */
15017 }
15019 /* Check to see if we already have the specialization we
15020 need. */
15026 {
15029 {
15031 complain,
15034 /* The context and type of an injected-class-name are
15035 the same, so we don't need to substitute both. */
15037 /* If CTX is unchanged, then T is in fact the
15038 specialization we want. That situation occurs when
15039 referencing a static data member within in its own
15040 class. We can use pointer equality, rather than
15041 same_type_p, because DECL_CONTEXT is always
15042 canonical... */
15044 /* ... unless T is a member template; in which
15045 case our caller can be willing to create a
15046 specialization of that template represented
15047 by T. */
15051 }
15054 {
15061 /* We're fully specializing a template declaration, so
15062 we need to coerce the innermost arguments corresponding to
15063 the template. */
15064 argvec = (coerce_template_parms
15071 }
15072 }
15073 else
15074 {
15076 /* Subsequent calls to pushdecl will fill this in. */
15078 /* A local variable. */
15080 /* Unless this is a reference to a static variable from an
15081 enclosing function, in which case we need to fill it in now. */
15083 {
15087 }
15089 }
15090 /* If we already have the specialization we need, there is
15091 nothing more to do. */
15093 {
15096 }
15098 /* Create a new node for the specialization we need. */
15100 {
15103 else
15113 /* Substituting the type might have recursively instantiated this
15114 same alias (c++/86171). */
15117 {
15120 }
15121 }
15124 {
15130 {
15131 /* It may seem that this case cannot occur, since:
15133 typedef void f();
15134 void g() { f x; }
15136 declares a function, not a variable. However:
15138 typedef void f();
15139 template <typename T> void g() { T t; }
15140 template void g<f>();
15142 is an attempt to declare a variable with function
15143 type. */
15145 /* R is not yet sufficiently initialized, so we
15146 just use its name. */
15149 }
15151 /* Wait until cp_finish_decl to set this again, to handle
15152 circular dependency (template/instantiate6.C). */
15157 {
15159 /* If the DECL_VALUE_EXPR is converted to the declared type,
15160 preserve the identity so that gimplify_type_sizes works. */
15166 {
15169 }
15178 else
15182 }
15186 }
15192 /* Clear out the mangled name and RTL for the instantiation. */
15198 /* The initializer must not be expanded until it is required;
15199 see [temp.inst]. */
15203 {
15209 /* Possibly limit visibility based on template args. */
15212 {
15216 }
15218 }
15221 {
15222 /* A static data member declaration is always marked
15223 external when it is declared in-class, even if an
15224 initializer is present. We mimic the non-template
15225 processing here. */
15234 }
15235 else
15236 {
15241 }
15250 /* Preserve a typedef that names a type. */
15252 {
15256 /* common_handle_aligned_attribute doesn't apply the alignment
15257 to DECL_ORIGINAL_TYPE. */
15261 }
15264 }
15269 }
15270 #undef RETURN
15272 out:
15273 /* Restore the file and line information. */
15277 }
15279 /* Substitute into the complete parameter type list PARMS. */
15281 tree
15283 tree args,
15284 tsubst_flags_t complain,
15285 tree in_decl)
15286 {
15288 }
15290 /* Substitute into the ARG_TYPES of a function type.
15291 If END is a TREE_CHAIN, leave it and any following types
15292 un-substituted. */
15294 static tree
15296 tree args,
15297 tree end,
15298 tsubst_flags_t complain,
15299 tree in_decl)
15300 {
15309 {
15310 /* For a pack expansion, perform substitution on the
15311 entire expression. Later on, we'll handle the arguments
15312 one-by-one. */
15317 /* So that we'll spin through the parameters, one by one. */
15319 else
15320 {
15321 /* We only partially substituted into the parameter
15322 pack. Our type is TYPE_PACK_EXPANSION. */
15325 }
15326 }
15327 else
15330 /* Check if a substituted type is erroneous before substituting into
15331 the rest of the chain. */
15333 {
15340 {
15342 {
15346 }
15348 }
15349 }
15351 /* We do not substitute into default arguments here. The standard
15352 mandates that they be instantiated only when needed, which is
15353 done in build_over_call. */
15356 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15357 since the new op() won't have any associated template arguments for us
15358 to refer to later. */
15370 {
15374 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15375 top-level qualifiers as required. */
15379 {
15380 /* We've instantiated a template before its default arguments
15381 have been parsed. This can happen for a nested template
15382 class, and is not an error unless we require the default
15383 argument in a call of this function. */
15384 remaining_arg_types
15387 remaining_arg_types);
15388 }
15389 else
15390 remaining_arg_types
15392 }
15395 }
15397 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15398 *not* handle the exception-specification for FNTYPE, because the
15399 initial substitution of explicitly provided template parameters
15400 during argument deduction forbids substitution into the
15401 exception-specification:
15403 [temp.deduct]
15405 All references in the function type of the function template to the
15406 corresponding template parameters are replaced by the specified tem-
15407 plate argument values. If a substitution in a template parameter or
15408 in the function type of the function template results in an invalid
15409 type, type deduction fails. [Note: The equivalent substitution in
15410 exception specifications is done only when the function is instanti-
15411 ated, at which point a program is ill-formed if the substitution
15412 results in an invalid type.] */
15414 static tree
15416 tree args,
15417 tsubst_flags_t complain,
15418 tree in_decl)
15419 {
15420 tree return_type;
15423 /* The TYPE_CONTEXT is not used for function/method types. */
15426 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15427 failure. */
15431 {
15432 /* Substitute the argument types. */
15444 {
15445 /* DR 1207: 'this' is in scope in the trailing return type. */
15447 }
15449 /* Substitute the return type. */
15453 {
15456 }
15457 }
15458 else
15459 /* Substitute the return type. */
15464 /* DR 486 clarifies that creation of a function type with an
15465 invalid return type is a deduction failure. */
15468 {
15470 {
15473 else
15475 }
15477 }
15480 {
15481 /* Substitute the argument types. */
15486 }
15488 /* Construct a new type node and return it. */
15491 }
15493 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15494 ARGS into that specification, and return the substituted
15495 specification. If there is no specification, return NULL_TREE. */
15497 static tree
15499 tree args,
15500 tsubst_flags_t complain,
15501 tree in_decl,
15503 {
15504 tree specs;
15505 tree new_specs;
15510 {
15511 /* A noexcept-specifier. */
15516 {
15517 /* Defer instantiation of noexcept-specifiers to avoid
15518 excessive instantiations (c++/49107). */
15521 {
15522 /* We already partially instantiated this member template,
15523 so combine the new args with the old. */
15528 }
15529 else
15530 {
15533 }
15534 }
15535 else
15536 {
15538 {
15540 args);
15542 }
15544 }
15546 /* We've instantiated a template before a noexcept-specifier
15547 contained therein has been parsed. This can happen for
15548 a nested template class:
15550 struct S {
15551 template<typename> struct B { B() noexcept(...); };
15552 struct A : B<int> { ... use B() ... };
15553 };
15555 where completing B<int> will trigger instantiating the
15556 noexcept, even though we only parse it at the end of S. */
15558 {
15561 }
15562 }
15564 {
15567 else
15569 {
15570 tree spec;
15575 {
15576 /* Expand the pack expansion type. */
15579 in_decl);
15585 else
15586 {
15587 /* We're substituting into a member template, so
15588 we got a TYPE_PACK_EXPANSION back. Add that
15589 expansion and move on. */
15593 expanded_specs,
15594 complain);
15597 }
15598 }
15601 {
15604 else
15609 complain);
15610 }
15613 }
15614 }
15616 }
15618 /* Substitute through a TREE_LIST of types or expressions, handling pack
15619 expansions. */
15621 tree
15623 {
15630 ;
15632 {
15636 }
15639 else
15647 ;
15649 {
15653 }
15656 else
15663 ;
15668 else
15679 /* Determine the number of arguments. */
15681 {
15684 }
15687 else
15691 {
15699 else
15701 }
15704 }
15706 /* Take the tree structure T and replace template parameters used
15707 therein with the argument vector ARGS. IN_DECL is an associated
15708 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15709 Issue error and warning messages under control of COMPLAIN. Note
15710 that we must be relatively non-tolerant of extensions here, in
15711 order to preserve conformance; if we allow substitutions that
15712 should not be allowed, we may allow argument deductions that should
15713 not succeed, and therefore report ambiguous overload situations
15714 where there are none. In theory, we could allow the substitution,
15715 but indicate that it should have failed, and allow our caller to
15716 make sure that the right thing happens, but we don't try to do this
15717 yet.
15719 This function is used for dealing with types, decls and the like;
15720 for expressions, use tsubst_expr or tsubst_copy. */
15722 tree
15724 {
15753 /* Reuse typedefs. We need to do this to handle dependent attributes,
15754 such as attribute aligned. */
15757 {
15761 {
15762 /* DECL represents an alias template and we want to
15763 instantiate it. */
15767 }
15771 {
15775 }
15780 else
15781 /* The typedef is from a non-template context. */
15785 {
15787 r = cp_build_qualified_type
15791 }
15792 else
15793 {
15794 /* We don't have an instantiation yet, so drop the typedef. */
15799 }
15800 }
15820 {
15824 /* Fall through. */
15850 {
15855 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15856 needed. */
15862 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15863 with TREE_SIDE_EFFECTS that indicates this is not an integral
15864 constant expression. */
15867 {
15870 }
15873 }
15877 {
15885 else
15887 }
15888 /* Fall through. */
15892 {
15906 {
15909 /* See through ARGUMENT_PACK_SELECT arguments. */
15912 }
15917 {
15919 /* If ARG is an argument pack, we don't actually want to
15920 perform a substitution here, because substitutions
15921 for argument packs are only done
15922 element-by-element. We can get to this point when
15923 substituting the type of a non-type template
15924 parameter pack, when that type actually contains
15925 template parameter packs from an outer template, e.g.,
15927 template<typename... Types> struct A {
15928 template<Types... Values> struct B { };
15929 }; */
15933 {
15936 /* When building concept checks for the purpose of
15937 deducing placeholders, we can end up with wildcards
15938 where types are expected. Adjust this to the deduced
15939 value. */
15947 return cp_build_qualified_type
15949 }
15951 {
15952 /* We are processing a type constructed from a
15953 template template parameter. */
15964 /* Consider this code:
15966 template <template <class> class Template>
15967 struct Internal {
15968 template <class Arg> using Bind = Template<Arg>;
15969 };
15971 template <template <class> class Template, class Arg>
15972 using Instantiate = Template<Arg>; //#0
15974 template <template <class> class Template,
15975 class Argument>
15976 using Bind =
15977 Instantiate<Internal<Template>::template Bind,
15978 Argument>; //#1
15980 When #1 is parsed, the
15981 BOUND_TEMPLATE_TEMPLATE_PARM representing the
15982 parameter `Template' in #0 matches the
15983 UNBOUND_CLASS_TEMPLATE representing the argument
15984 `Internal<Template>::template Bind'; We then want
15985 to assemble the type `Bind<Argument>' that can't
15986 be fully created right now, because
15987 `Internal<Template>' not being complete, the Bind
15988 template cannot be looked up in that context. So
15989 we need to "store" `Bind<Argument>' for later
15990 when the context of Bind becomes complete. Let's
15991 store that in a TYPENAME_TYPE. */
15995 argvec),
15996 typename_type,
15997 complain);
15999 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16000 are resolving nested-types in the signature of a
16001 member function templates. Otherwise ARG is a
16002 TEMPLATE_DECL and is the real template to be
16003 instantiated. */
16011 complain);
16012 return cp_build_qualified_type
16014 }
16017 else
16018 /* TEMPLATE_PARM_INDEX. */
16020 }
16023 /* This can happen during the attempted tsubst'ing in
16024 unify. This means that we don't yet have any information
16025 about the template parameter in question. */
16028 /* Early in template argument deduction substitution, we don't
16029 want to reduce the level of 'auto', or it will be confused
16030 with a normal template parm in subsequent deduction.
16031 Similarly, don't reduce the level of template parameters to
16032 avoid mismatches when deducing their types. */
16036 /* If we get here, we must have been looking at a parm for a
16037 more deeply nested template. Make a new version of this
16038 template parameter, but with a lower level. */
16040 {
16045 {
16047 r = cp_build_qualified_type
16051 }
16058 /* Break infinite recursion when substituting the constraints
16066 /* Cache the simple case of lowering a type parameter. */
16068 else
16069 {
16081 /* Propagate constraints on placeholders since they are
16082 only instantiated during satisfaction. */
16086 {
16088 /* We might need to substitute into the types of non-type
16089 template parameters. */
16101 }
16105 else
16107 }
16111 /* OK, now substitute the type of the non-type parameter. We
16112 couldn't do it earlier because it might be an auto parameter,
16113 and we wouldn't need to if we had an argument. */
16122 }
16125 }
16131 /* We should never be tsubsting a binfo. */
16135 /* A vector of template arguments. */
16141 {
16145 /* [temp.deduct]
16147 Type deduction may fail for any of the following
16148 reasons:
16150 -- Attempting to create a pointer to reference type.
16151 -- Attempting to create a reference to a reference type or
16152 a reference to void.
16154 Core issue 106 says that creating a reference to a reference
16155 during instantiation is no longer a cause for failure. We
16156 only enforce this check in strict C++98 mode. */
16160 {
16163 /* We keep track of the last time we issued this error
16164 message to avoid spewing a ton of messages during a
16165 single bad template instantiation. */
16168 {
16173 else
16176 }
16179 }
16183 {
16185 {
16188 type);
16189 else
16191 type);
16192 }
16194 }
16196 {
16200 }
16202 /* In C++0x, during template argument substitution, when there is an
16203 attempt to create a reference to a reference type, reference
16204 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16206 "If a template-argument for a template-parameter T names a type
16207 that is a reference to a type A, an attempt to create the type
16208 'lvalue reference to cv T' creates the type 'lvalue reference to
16209 A,' while an attempt to create the type type rvalue reference to
16210 cv T' creates the type T"
16211 */
16212 r = cp_build_reference_type
16215 else
16220 /* Will this ever be needed for TYPE_..._TO values? */
16224 }
16226 {
16229 {
16230 /* [temp.deduct]
16232 Type deduction may fail for any of the following
16233 reasons:
16235 -- Attempting to create "pointer to member of T" when T
16236 is not a class type. */
16240 }
16242 {
16246 }
16248 {
16252 }
16255 {
16256 /* The type of the implicit object parameter gets its
16257 cv-qualifiers from the FUNCTION_TYPE. */
16258 tree memptr;
16259 tree method_type
16264 complain);
16265 }
16266 else
16269 complain);
16270 }
16273 {
16274 tree fntype;
16275 tree specs;
16280 /* Substitute the exception specification. */
16288 }
16290 {
16295 /* As an optimization, we avoid regenerating the array type if
16296 it will obviously be the same as T. */
16300 /* These checks should match the ones in create_array_type_for_decl.
16302 [temp.deduct]
16304 The deduction may fail for any of the following reasons:
16306 -- Attempting to create an array with an element type that
16307 is void, a function type, or a reference type, or [DR337]
16308 an abstract class type. */
16314 {
16318 }
16331 {
16334 }
16337 }
16340 {
16343 {
16349 {
16354 }
16356 }
16357 else
16369 {
16373 }
16375 {
16376 /* Normally, make_typename_type does not require that the CTX
16377 have complete type in order to allow things like:
16379 template <class T> struct S { typename S<T>::X Y; };
16381 But, such constructs have already been resolved by this
16382 point, so here CTX really should have complete type, unless
16383 it's a partial instantiation. */
16386 }
16395 {
16398 }
16401 {
16403 {
16407 else
16409 }
16411 {
16415 else
16417 }
16418 }
16420 return cp_build_qualified_type
16422 }
16425 {
16437 }
16440 {
16441 tree type;
16455 complain);
16456 }
16459 {
16460 tree type;
16477 else
16478 {
16482 /* In a template ~id could be either a complement expression
16483 or an unqualified-id naming a destructor; if instantiating
16484 it produces an expression, it's not an id-expression or
16485 member access. */
16488 }
16493 }
16496 {
16503 }
16522 /* We should use one of the expression tsubsts for these codes. */
16528 }
16529 }
16531 /* OLDFNS is a lookup set of member functions from some class template, and
16532 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16533 of that class template. Return the subset of NEWFNS which are
16534 specializations of a function from OLDFNS. */
16536 static tree
16538 {
16539 /* Record all member functions from the old lookup set OLDFNS into
16540 VISIBLE_SET. */
16544 {
16546 {
16547 /* Imprecisely handle dependent using-decl by keeping all members
16548 in the new lookup set that are defined in a base class, i.e.
16549 members that could plausibly have been introduced by this
16550 dependent using-decl.
16551 FIXME: Track which members are introduced by a dependent
16552 using-decl precisely, perhaps by performing another lookup
16553 from the substituted USING_DECL_SCOPE. */
16556 }
16557 else
16559 }
16561 /* Returns true iff (a less specialized version of) FN appeared in
16562 the old lookup set OLDFNS. */
16565 /* FN is a member function from a base class, introduced via a
16566 using-decl; if it might have been introduced by a dependent
16567 using-decl then just conservatively keep it, otherwise look
16568 in the old lookup set for FN exactly. */
16571 /* FN is a member function template from the current class;
16572 look in the old lookup set for the TEMPLATE_DECL from which
16573 it was specialized. */
16575 else
16576 /* FN is a non-template member function from the current class;
16577 look in the old lookup set for the FUNCTION_DECL from which
16578 it was specialized. */
16581 };
16586 {
16589 }
16593 /* Filter out from NEWFNS the member functions that weren't
16594 previously visible according to OLDFNS. */
16599 {
16601 filtered_size++;
16602 }
16608 }
16610 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16611 expression on the left-hand side of the "." or "->" operator. We
16612 only do the lookup if we had a dependent BASELINK. Otherwise we
16613 adjust it onto the instantiated heirarchy. */
16615 static tree
16618 {
16630 {
16637 }
16645 {
16650 /* See maybe_dependent_member_ref. */
16652 {
16655 template_args);
16658 }
16661 /* Treat as-if non-dependent below. */
16666 complain);
16668 {
16669 /* Filter out from the new lookup set those functions which didn't
16670 appear in the original lookup set (in a less specialized form).
16671 This is needed to preserve the consistency of member lookup
16672 performed in an incomplete-class context, within which
16673 later-declared members ought to remain invisible. */
16676 binfo_type);
16678 }
16681 {
16687 }
16690 }
16691 else
16692 {
16693 /* We're going to overwrite pieces below, make a duplicate. */
16697 {
16698 /* The decl we found was from non-dependent scope, but we still need
16699 to update the binfos for the instantiated qualifying_scope. */
16703 }
16704 }
16706 /* If lookup found a single function, mark it as used at this point.
16707 (If lookup found multiple functions the one selected later by
16708 overload resolution will be marked as used at that point.) */
16710 {
16716 /* We might have instantiated an auto function. */
16718 }
16721 {
16722 /* Add back the template arguments, if present. */
16727 /* Update the conversion operator type. */
16729 }
16735 {
16737 qualifying_scope,
16738 object_type);
16740 /* We need to call adjust_result_of_qualified_name_lookup in case the
16741 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16742 so that we still get virtual function binding. */
16744 }
16747 }
16749 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16750 true if the qualified-id will be a postfix-expression in-and-of
16751 itself; false if more of the postfix-expression follows the
16752 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16753 of "&". */
16755 static tree
16759 {
16760 tree expr;
16761 tree scope;
16762 tree name;
16764 tree template_args;
16769 /* Figure out what name to look up. */
16772 {
16781 }
16782 else
16783 {
16786 }
16788 /* Substitute into the qualifying scope. When there are no ARGS, we
16789 are just trying to simplify a non-dependent expression. In that
16790 case the qualifying scope may be dependent, and, in any case,
16791 substituting will not help. */
16794 {
16797 }
16798 else
16802 {
16804 /* We built one in tsubst_baselink. */
16806 else
16807 {
16810 template_args);
16812 QUALIFIED_NAME_IS_TEMPLATE
16814 }
16817 }
16820 {
16822 {
16823 /* A BIT_NOT_EXPR is used to represent a destructor. */
16825 {
16829 }
16830 else
16833 }
16834 else
16838 {
16840 {
16844 }
16846 }
16847 }
16850 {
16854 /* Remember that there was a reference to this entity. */
16857 }
16860 {
16866 }
16869 {
16870 /* We may be repeating a check already done during parsing, but
16871 if it was well-formed and passed then, it will pass again
16872 now, and if it didn't, we wouldn't have got here. The case
16873 we want to catch is when we couldn't tell then, and can now,
16874 namely when templ prior to substitution was an
16875 identifier. */
16881 complain);
16882 else
16884 }
16890 {
16891 expr = (adjust_result_of_qualified_name_lookup
16893 expr = (finish_qualified_id_expr
16897 }
16899 /* Expressions do not generally have reference type. */
16901 /* However, if we're about to form a pointer-to-member, we just
16902 want the referenced member referenced. */
16912 }
16914 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16915 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16916 for tsubst. */
16918 static tree
16921 {
16930 {
16932 {
16934 {
16939 }
16940 }
16942 {
16943 /* If we had an initializer but it
16944 instantiated to nothing,
16945 value-initialize the object. This will
16946 only occur when the initializer was a
16947 pack expansion where the parameter packs
16948 used in that expansion were of length
16949 zero. */
16955 }
16956 }
16959 }
16961 /* If T is a reference to a dependent member of the current instantiation C and
16962 we are trying to refer to that member in a partial instantiation of C,
16963 return a SCOPE_REF; otherwise, return NULL_TREE.
16965 This can happen when forming a C++17 deduction guide, as in PR96199. */
16967 static tree
16969 tree in_decl)
16970 {
16987 {
16996 complain);
16997 }
17002 {
17008 }
17011 {
17014 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17015 scope, but it doesn't need to be rewritten again. */
17019 }
17023 else
17026 }
17028 /* Like tsubst, but deals with expressions. This function just replaces
17029 template parms; to finish processing the resultant expression, use
17030 tsubst_copy_and_build or tsubst_expr. */
17032 static tree
17034 {
17036 tree r;
17047 {
17052 {
17053 /* We get here for a use of 'this' in an NSDMI. */
17057 /* This can happen for a parameter name used later in a function
17058 declaration (such as in a late-specified return type). Just
17059 make a dummy decl, since it's only used for its type. */
17062 /* Give it the template pattern as its context; its true context
17063 hasn't been instantiated yet and this is good enough for
17064 mangling. */
17066 }
17075 {
17076 tree enum_type;
17077 tree v;
17084 /* Unfortunately, we cannot just call lookup_name here.
17085 Consider:
17087 template <int I> int f() {
17088 enum E { a = I };
17089 struct S { void g() { E e = a; } };
17090 };
17092 When we instantiate f<7>::S::g(), say, lookup_name is not
17093 clever enough to find f<7>::a. */
17094 enum_type
17104 /* We didn't find the name. That should never happen; if
17105 name-lookup found it during preliminary parsing, we
17106 should find it again here during instantiation. */
17108 }
17113 {
17114 tree ctx;
17119 {
17122 {
17126 }
17128 }
17129 }
17138 {
17139 /* Local specialization will usually have been created when
17140 we instantiated the DECL_EXPR_DECL. */
17143 {
17144 /* We're in a generic lambda referencing a local extern
17145 from an outer block-scope of a non-template. */
17148 }
17149 }
17152 {
17155 {
17156 /* First try name lookup to find the instantiation. */
17159 {
17161 {
17162 /* During error-recovery we may find a non-variable,
17163 even an OVERLOAD: just bail out and avoid ICEs and
17164 duplicate diagnostics (c++/62207). */
17167 }
17169 {
17170 /* Make sure the one we found is the one we want. */
17174 }
17175 }
17179 else
17180 {
17181 /* This can happen for a variable used in a
17182 late-specified return type of a local lambda, or for a
17183 local static or constant. Building a new VAR_DECL
17184 should be OK in all those cases. */
17187 /* Avoid infinite recursion (79640). */
17190 {
17191 /* We can't call cp_finish_decl, so handle the
17192 initializer by hand. */
17207 }
17209 || processing_contract_condition
17216 }
17217 /* Remember this for subsequent uses. */
17220 }
17223 }
17224 else
17248 {
17249 /* Template template argument like the following example need
17250 special treatment:
17252 template <template <class> class TT> struct C {};
17253 template <class T> struct D {
17254 template <class U> struct E {};
17255 C<E> c; // #1
17256 };
17257 D<int> d; // #2
17259 We are processing the template argument `E' in #1 for
17260 the template instantiation #2. Originally, `E' is a
17261 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17262 have to substitute this with one having context `D<int>'. */
17267 }
17268 else
17269 /* Ordinary template template argument. */
17274 {
17275 /* Handle location wrappers by substituting the wrapped node
17276 first, *then* reusing the resulting type. Doing the type
17277 first ensures that we handle template parameters and
17278 parameter pack expansions. */
17280 {
17284 }
17288 {
17289 /* Wrapper to make a C++20 template parameter object const. */
17292 {
17293 /* The template argument is not const, presumably because
17294 it is still dependent, and so not the const template parm
17295 object. */
17301 {
17302 /* Don't add a wrapper to these. */
17305 }
17306 else
17307 /* Do add a wrapper otherwise (in particular, if op is
17308 another TEMPLATE_PARM_INDEX). */
17310 }
17312 }
17313 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17315 {
17320 }
17321 /* We shouldn't see any other uses of these in templates. */
17323 }
17331 CASE_CONVERT:
17332 {
17339 }
17342 {
17348 }
17353 {
17362 /* We only want to compute the number of arguments. */
17365 else
17372 {
17374 /* Set TREE_USED for the benefit of -Wunused. */
17378 }
17386 {
17391 else
17399 else
17404 }
17405 else
17407 }
17409 {
17417 }
17418 /* Fall through */
17434 {
17440 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17441 set for possible later diagnostics. */
17448 }
17451 {
17455 {
17458 }
17460 }
17463 {
17464 tree object;
17465 tree name;
17470 {
17474 }
17477 {
17487 }
17492 in_decl);
17493 else
17496 }
17532 {
17536 }
17539 {
17544 }
17547 {
17551 }
17554 {
17562 }
17568 {
17575 }
17578 {
17585 }
17588 {
17595 }
17598 {
17599 /* Substituted template arguments */
17609 else
17611 }
17614 {
17634 }
17659 /* Fall through. */
17662 {
17665 }
17666 else
17670 /* This is handled by tsubst_copy_and_build. */
17674 {
17678 }
17681 /* We shouldn't have built any of these during initial template
17682 generation. Instead, they should be built during instantiation
17683 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17687 {
17697 }
17715 {
17716 /* Instantiate any typedefs in the type. */
17721 }
17724 {
17728 {
17731 }
17733 }
17736 /* These can sometimes show up in a partial instantiation, but never
17737 involve template parms. */
17753 /* ??? There's no point in copying it for now, but maybe some
17754 day it will contain more information, such as a pointer back
17755 to the containing function, inlined copy or so. */
17762 /* We shouldn't get here, but keep going if !flag_checking. */
17766 }
17767 }
17769 /* Helper function for tsubst_omp_clauses, used for instantiation of
17770 OMP_CLAUSE_DECL of clauses. */
17772 static tree
17775 {
17779 /* Handle OpenMP iterators. */
17783 {
17784 tree ret;
17787 else
17788 {
17792 {
17806 }
17810 }
17814 }
17816 /* Handle an OpenMP array section represented as a TREE_LIST (or
17817 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17818 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17819 TREE_LIST. We can handle it exactly the same as an array section
17820 (purpose, value, and a chain), even though the nomenclature
17821 (low_bound, length, etc) is different. */
17823 {
17824 tree low_bound
17837 }
17839 /* Undo convert_from_reference tsubst_expr could have called. */
17845 }
17847 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17849 static tree
17852 {
17858 {
17864 {
17867 {
17873 }
17874 /* FALLTHRU */
17904 /* FALLTHRU */
17937 {
17940 {
17947 }
17948 else
17950 }
17977 {
17980 }
17985 else
18016 }
18019 {
18036 /* tsubst_expr on SCOPE_REF results in returning
18037 finish_non_static_data_member result. Undo that here. */
18041 {
18046 {
18050 CASE_CONVERT:
18059 /* FALLTHRU */
18063 }
18064 }
18070 {
18073 {
18076 }
18077 }
18081 }
18082 }
18086 {
18091 {
18094 }
18095 }
18097 }
18099 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18101 static tree
18103 tree in_decl)
18104 {
18105 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18123 {
18126 else
18127 {
18131 }
18132 }
18137 #undef RECUR
18138 }
18140 /* Used to temporarily communicate the list of #pragma omp parallel
18141 clauses to #pragma omp for instantiation if they are combined
18142 together. */
18149 /* Substitute one OMP_FOR iterator. */
18151 static bool
18155 {
18156 #define RECUR(NODE) \
18157 tsubst_expr ((NODE), args, complain, in_decl)
18169 {
18172 {
18177 {
18187 else
18189 {
18191 {
18197 }
18200 }
18201 }
18202 }
18206 }
18208 {
18209 /* We need to jump through some hoops to handle declarations in the
18210 init-statement, since we might need to handle auto deduction,
18211 but we need to keep control of initialization. */
18215 }
18216 else
18217 {
18219 {
18222 {
18226 {
18230 CASE_CONVERT:
18238 {
18241 }
18242 /* FALLTHRU */
18246 }
18247 }
18248 }
18249 else
18251 }
18253 {
18259 }
18260 else
18264 {
18270 NULL_TREE);
18271 else
18273 }
18276 {
18283 {
18288 }
18291 }
18301 {
18303 {
18304 /* Declare the variable, but don't let that initialize it. */
18309 }
18312 {
18316 {
18325 }
18326 else
18330 {
18335 }
18336 else
18340 }
18346 }
18349 {
18350 /* Declare and initialize the variable. */
18353 }
18355 {
18360 {
18362 {
18368 {
18371 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18376 }
18379 {
18381 decl);
18383 }
18386 {
18388 decl);
18390 }
18391 else
18393 }
18396 }
18398 {
18401 ? OMP_CLAUSE_LASTPRIVATE
18406 {
18409 }
18410 }
18411 }
18414 {
18418 }
18419 else
18423 {
18434 {
18442 }
18443 else
18449 {
18455 }
18459 {
18467 }
18468 else
18474 }
18483 #undef RECUR
18484 }
18486 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18487 of OMP_TARGET's body. */
18489 static tree
18491 {
18494 {
18503 }
18505 }
18507 /* Helper function for tsubst_expr. For decomposition declaration
18508 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18509 also the corresponding decls representing the identifiers
18510 of the decomposition declaration. Return DECL if successful
18511 or error_mark_node otherwise, set *FIRST to the first decl
18512 in the list chained through DECL_CHAIN and *CNT to the number
18513 of such decls. */
18515 static tree
18519 {
18524 decl2
18529 {
18531 {
18534 }
18546 else
18547 {
18551 }
18558 {
18561 }
18562 else
18564 }
18567 }
18569 /* Return the proper local_specialization for init-capture pack DECL. */
18571 static tree
18573 {
18574 /* We handle normal pack captures by forwarding to the specialization of the
18575 captured parameter. We can't do that for pack init-captures; we need them
18576 to have their own local_specialization. We created the individual
18577 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18578 when we process the DECL_EXPR for the pack init-capture in the template.
18579 So, how do we find them? We don't know the capture proxy pack when
18580 building the individual resulting proxies, and we don't know the
18581 individual proxies when instantiating the pack. What we have in common is
18582 the FIELD_DECL.
18584 So...when we instantiate the FIELD_DECL, we stick the result in
18585 local_specializations. Then at the DECL_EXPR we look up that result, see
18586 how many elements it has, synthesize the names, and look them up. */
18600 {
18605 }
18607 {
18612 else
18614 }
18616 }
18618 /* T is an operand of a template tree being substituted. Return whether
18619 T is dependent such that we should suppress some warnings that would
18620 make sense if the substituted expression were written directly, like
18621 template <int I> bool f() { return I == 2; }
18622 We don't want to warn when instantiating f that comparing two constants
18623 always has the same value.
18625 This is a more limited concept of dependence than instantiation-dependent;
18626 here we don't care whether substitution could fail. */
18628 static bool
18630 {
18639 }
18641 /* Like tsubst_copy for expressions, etc. but also does semantic
18642 processing. */
18644 tree
18646 {
18647 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18648 #define RECUR(NODE) \
18649 tsubst_expr ((NODE), args, complain, in_decl)
18652 tree r;
18653 location_t loc;
18665 {
18667 {
18671 }
18700 else
18713 {
18718 }
18722 {
18724 tree init;
18730 {
18733 {
18737 {
18742 }
18744 }
18745 else
18746 {
18747 /* This is a non-dependent using-decl, and we'll have
18748 used the names it found during template parsing. We do
18749 not want to do the lookup again, because we might not
18750 find the things we found then. */
18753 /* We still need to push the bindings so that we can look up
18754 this name later. */
18757 }
18758 }
18761 {
18762 /* We're in tsubst_lambda_expr, we've already inserted a new
18763 capture proxy, so look it up and register it. */
18764 tree inst;
18766 {
18770 }
18772 {
18773 inst = (retrieve_local_specialization
18777 }
18778 else
18783 }
18790 /* Don't copy the old closure; we'll create a new one in
18791 tsubst_lambda_expr. */
18793 else
18794 {
18798 {
18799 /* By marking the declaration as instantiated, we avoid
18800 trying to instantiate it. Since instantiate_decl can't
18801 handle local variables, and since we've already done
18802 all that needs to be done, that's the right thing to
18803 do. */
18808 /* Anonymous aggregates are a special case. */
18811 {
18814 {
18818 }
18820 }
18825 {
18833 }
18834 else
18835 {
18852 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18858 /* In a non-template function, VLA type declarations are
18859 handled in grokdeclarator; for templates, handle them
18860 now. */
18864 {
18868 asmspec_tree
18872 }
18878 }
18879 }
18880 }
18883 }
18893 {
18897 }
18902 {
18903 /* Construct another range_for, if this is not a final
18904 substitution (for inside a generic lambda of a
18905 template). Otherwise convert to a regular for. */
18907 stmt = (processing_template_decl
18924 {
18930 }
18931 else
18932 {
18938 }
18944 }
18951 {
18955 }
18961 {
18965 }
18977 {
18983 }
18986 {
18987 /* We're partially instantiating a generic lambda, but the condition
18988 of the constexpr if is still dependent. Don't substitute into the
18989 branches now, just remember the template arguments. */
18997 }
19001 {
19006 }
19007 else
19008 {
19016 }
19022 {
19032 }
19040 else
19048 else
19069 {
19075 {
19080 }
19081 }
19085 {
19087 tree label;
19094 }
19100 /* Computed goto's must be tsubst'd into. On the other hand,
19101 non-computed gotos must not be; the identifier in question
19102 will have no binding. */
19104 else
19110 {
19127 }
19132 {
19137 }
19138 else
19139 {
19144 else
19151 else
19157 else
19159 }
19163 {
19167 {
19169 /* Prevent instantiate_decl from trying to instantiate
19170 this variable. We've already done all that needs to be
19171 done. */
19174 }
19179 }
19185 {
19186 /* Local classes are not independent templates; they are
19187 instantiated along with their containing function. And this
19188 way we don't have to deal with pushing out of one local class
19189 to instantiate a member of another local class. */
19190 /* Closures are handled by the LAMBDA_EXPR. */
19200 }
19204 {
19205 tree condition;
19216 }
19223 in_decl);
19245 {
19252 }
19268 {
19282 in_decl);
19284 {
19291 }
19302 any_range_for
19309 {
19318 }
19319 else
19324 else
19331 else
19332 {
19340 }
19343 t));
19345 }
19351 /* FALLTHRU */
19361 in_decl);
19363 {
19368 }
19369 else
19370 {
19374 }
19379 {
19381 "%<#pragma omp critical%> with %<hint%> clause requires "
19384 }
19395 {
19398 {
19403 }
19404 else
19405 {
19409 }
19411 }
19412 else
19414 OMP_CLAUSE_DEPEND_INVALID,
19423 ? C_ORT_ACC
19442 {
19445 /* For combined target teams, ensure the num_teams and
19446 thread_limit clause expressions are evaluated on the host,
19447 before entering the target construct. */
19456 {
19459 tf_none);
19466 OMP_CLAUSE_FIRSTPRIVATE);
19470 }
19471 }
19508 {
19512 }
19513 else
19524 /* FALLTHRU */
19542 {
19548 {
19551 }
19553 {
19557 {
19560 }
19565 }
19566 else
19567 {
19570 }
19575 }
19576 else
19577 {
19584 {
19587 }
19590 {
19595 {
19598 }
19600 {
19604 {
19607 }
19612 }
19613 else
19614 {
19617 }
19621 }
19622 else
19623 {
19627 }
19631 }
19635 {
19641 {
19645 {
19650 }
19654 }
19655 else
19656 {
19661 }
19662 }
19666 {
19670 }
19683 /* If the first operand was a statement, we're done with it. */
19688 complain));
19704 }
19707 out:
19710 #undef RECUR
19711 #undef RETURN
19712 }
19714 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19715 function. For description of the body see comment above
19716 cp_parser_omp_declare_reduction_exprs. */
19718 static void
19720 {
19726 tree_stmt_iterator tsi;
19737 {
19744 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19745 expect to be pushing it. */
19757 }
19759 {
19779 }
19780 }
19782 /* T is a postfix-expression that is not being used in a function
19783 call. Return the substituted version of T. */
19785 static tree
19787 tsubst_flags_t complain,
19788 tree in_decl)
19789 {
19793 else
19797 }
19799 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19800 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19801 dependent init-capture. */
19803 static void
19805 tsubst_flags_t complain)
19806 {
19808 {
19811 {
19815 }
19822 }
19824 }
19826 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19827 instantiation context. Instantiating a pack expansion containing a lambda
19828 might result in multiple lambdas all based on the same lambda in the
19829 template. */
19831 tree
19833 {
19848 else
19859 {
19864 else
19876 {
19877 /* For a VLA, simply tsubsting the field type won't work, we need to
19878 go through add_capture again. XXX do we want to do this for all
19879 captures? */
19880 tree name = (get_identifier
19888 }
19895 {
19896 /* Remember these for when we've pushed local_specializations. */
19899 }
19905 {
19913 complain);
19914 }
19915 else
19916 {
19918 complain);
19922 }
19923 }
19932 /* If we're pushed into another scope (PR105652), fix it. */
19937 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19955 else
19956 {
19957 /* The body of a lambda-expression is not a subexpression of the
19958 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19959 which would be skipped if cp_unevaluated_operand. */
19960 cp_evaluated ev;
19962 /* Fix the type of 'this'. */
19966 tree inst = (oldtmpl
19970 {
19973 }
19979 /* Let finish_function set this. */
19985 else
19986 /* Still increment function_depth so that we don't GC in the
19987 middle of an expression. */
19997 /* Now record them for lookup_init_capture_pack. */
20000 {
20004 }
20010 {
20011 /* We might not partially instantiate some parts of the function, so
20012 copy these flags from the original template. */
20018 }
20020 /* [temp.deduct] A lambda-expression appearing in a function type or a
20021 template parameter is not considered part of the immediate context for
20022 the purposes of template argument deduction. */
20027 /* We already have a body block from start_lambda_function, we don't
20028 need another to confuse NRV (91217). */
20039 else
20042 /* The capture list was built up in reverse order; fix that now. */
20049 }
20051 out:
20057 }
20059 /* Subroutine of maybe_fold_fn_template_args. */
20061 static bool
20063 {
20066 {
20072 {
20075 }
20080 {
20084 }
20085 }
20088 }
20090 /* Try to do constant evaluation of any explicit template arguments in FN
20091 before overload resolution, to get any errors only once. Return true iff
20092 we didn't have any problems folding. */
20094 static bool
20096 {
20114 }
20116 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20117 handling. */
20119 static void
20122 {
20125 {
20131 else
20132 {
20133 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20136 {
20141 {
20146 }
20147 }
20148 else
20149 /* A partial substitution. Add one entry. */
20151 }
20152 }
20153 }
20155 /* Like tsubst but deals with expressions and performs semantic
20156 analysis. */
20158 tree
20160 tree args,
20161 tsubst_flags_t complain,
20162 tree in_decl)
20163 {
20164 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20165 #define RECUR(NODE) \
20166 tsubst_copy_and_build (NODE, args, complain, in_decl)
20169 location_t save_loc;
20178 /* N3276 decltype magic only applies to calls at the top level or on the
20179 right side of a comma. */
20184 {
20187 /* Fall through. */
20189 {
20190 tree decl;
20191 cp_id_kind idk;
20195 {
20198 }
20200 /* Look up the name. */
20203 /* By convention, expressions use ERROR_MARK_NODE to indicate
20204 failure, not NULL_TREE. */
20218 input_location);
20222 {
20226 }
20228 }
20231 {
20232 tree object;
20243 {
20248 }
20251 {
20258 /* If we built a function concept check, return the underlying
20259 template-id. So we can evaluate it as a function call. */
20264 }
20267 {
20269 complain);
20272 }
20275 {
20278 }
20279 else
20289 {
20290 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20291 name lookup found nothing when parsing the template name. */
20294 }
20295 else
20297 }
20300 {
20304 {
20305 /* A type conversion to reference type will be enclosed in
20306 such an indirect ref, but the substitution of the cast
20307 will have also added such an indirect ref. */
20309 }
20310 else
20319 }
20322 {
20326 }
20329 {
20333 {
20338 }
20340 /* We'll pass this to convert_nontype_argument again, we don't need
20341 to actually perform any conversion here. */
20349 flags));
20350 }
20353 {
20359 }
20366 {
20367 tree type;
20381 {
20401 }
20404 }
20407 {
20411 }
20436 {
20443 }
20446 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20457 else
20459 in_decl);
20494 {
20495 /* If either OP0 or OP1 was value- or type-dependent, suppress
20496 warnings that depend on the range of the types involved. */
20510 tree r = build_x_binary_op
20512 op0,
20514 ? ERROR_MARK
20516 op1,
20518 ? ERROR_MARK
20527 }
20530 {
20538 }
20554 {
20556 releasing_vec index_exp_list;
20558 index_exp_list);
20560 tree r;
20566 else
20571 }
20580 /* Fall through */
20583 {
20584 tree r;
20592 {
20593 /* When there are no ARGS, we are trying to evaluate a
20594 non-dependent expression from the parser. Trying to do
20595 the substitutions may not work. */
20598 }
20599 else
20600 {
20605 else
20609 }
20614 else
20619 {
20621 {
20623 {
20627 }
20628 else
20632 }
20634 }
20636 }
20639 {
20647 }
20661 {
20666 tree r = build_x_modify_expr
20670 /* TREE_NO_WARNING must be set if either the expression was
20671 parenthesized or it uses an operator such as >>= rather
20672 than plain assignment. In the former case, it was already
20673 set and must be copied. In the latter case,
20674 build_x_modify_expr sets it and it must not be reset
20675 here. */
20680 }
20685 /* Remember that there was a reference to this entity. */
20692 {
20697 tree ret;
20704 else
20705 {
20709 }
20711 /* If there was an initializer in the original tree, but it
20712 instantiated to an empty list, then we should pass a
20713 non-NULL empty vector to tell build_new that it was an
20714 empty initializer() rather than no initializer. This can
20715 only happen when the initializer is a pack expansion whose
20716 parameter packs are of length zero. */
20721 else
20722 {
20726 else
20727 {
20730 }
20731 }
20733 /* Avoid passing an enclosing decl to valid_array_size_p. */
20740 complain);
20748 }
20751 {
20757 complain));
20758 }
20761 {
20765 op0,
20769 }
20772 {
20773 tree function;
20777 tree ret;
20780 /* Internal function with no arguments. */
20784 /* When we parsed the expression, we determined whether or
20785 not Koenig lookup should be performed. */
20788 {
20791 }
20793 {
20798 }
20803 {
20804 /* Do nothing; calling tsubst_copy_and_build on an identifier
20805 would incorrectly perform unqualified lookup again.
20807 Note that we can also have an IDENTIFIER_NODE if the earlier
20808 unqualified lookup found a dependent local extern declaration
20809 (as per finish_call_expr); in that case koenig_p will be false
20810 and we do want to do the lookup again to find the substituted
20811 declaration. */
20815 /* Use tsubst_copy to substitute through the template arguments
20816 of the template-id without performing unqualified lookup of
20817 the template name. */
20819 }
20820 else
20821 {
20823 {
20829 }
20830 else
20835 /* Avoid error about taking the address of a constructor. */
20840 /* When KOENIG_P, we don't want to mark_used the callee before
20841 augmenting the overload set via ADL, so during this initial
20842 substitution we disable mark_used by setting tf_conv (68942). */
20848 }
20851 releasing_vec call_args;
20853 call_args);
20855 /* Stripped-down processing for a call in a thunk. Specifically, in
20856 the thunk template for a generic lambda. */
20858 {
20859 /* Now that we've expanded any packs, the number of call args
20860 might be different. */
20864 {
20871 }
20872 /* We aren't going to do normal overload resolution, so force the
20873 template-id to resolve. */
20876 {
20877 /* In a thunk, pass through args directly, without any
20878 conversions. */
20883 }
20885 {
20886 /* If there are no other args, just push 'this'. */
20889 else
20890 {
20891 /* Otherwise, shift the other args over to make room. */
20897 }
20898 }
20901 /* The thunk location is not interesting. */
20908 }
20910 /* We do not perform argument-dependent lookup if normal
20911 lookup finds a non-function, in accordance with the
20912 resolution of DR 218. */
20915 /* If lookup found a member function, the Koenig lookup is
20916 not appropriate, even if an unqualified-name was used
20917 to denote the function. */
20920 /* C++20 P0846: Lookup found nothing. */
20923 /* Only do this when substitution turns a dependent call
20924 into a non-dependent call. */
20936 {
20941 {
20942 /* For backwards compatibility and good diagnostics, try
20943 the unqualified lookup again if we aren't in SFINAE
20944 context. */
20951 {
20954 "and no declarations were found by "
20955 "argument-dependent lookup at the point "
20960 /* In a lambda fn, we have to be careful to not
20961 introduce new this captures. Legacy code can't
20962 be using lambdas anyway, so it's ok to be
20963 stricter. Be strict with C++20 template-id ADL too.
20964 And be strict if we're already failing anyway. */
20970 else
20974 {
20985 {
20988 "declarations in dependent base %qT are "
20994 else
20998 }
20999 else
21001 "%qD declared here, later in the "
21005 }
21008 }
21009 }
21011 {
21015 }
21016 }
21018 /* Remember that there was a reference to this entity. */
21020 {
21024 /* We should already have called mark_used when taking the
21025 address of this function, but do so again anyway to make
21026 sure it's odr-used: at worst this is a no-op, but if we
21027 obtained this FUNCTION_DECL as part of ahead-of-time overload
21028 resolution then that call to mark_used wouldn't have marked it
21029 odr-used yet (53164). */
21034 }
21039 /* Put back tf_decltype for the actual call. */
21044 {
21048 {
21050 "wrong number of arguments to "
21053 }
21054 else
21062 {
21064 "wrong number of arguments to "
21068 }
21072 complain);
21078 {
21080 complain);
21084 }
21089 {
21091 "wrong number of arguments to "
21094 }
21095 else
21096 {
21101 {
21104 }
21107 }
21111 /* Unsupported internal function with arguments. */
21113 }
21118 complain);
21120 {
21135 complain);
21136 else
21137 ret = (build_new_method_call
21142 complain));
21143 }
21145 {
21146 /* FUNCTION is a template-id referring to a concept definition. */
21151 /* Calls to standard and variable concepts should have been
21152 previously diagnosed. */
21155 /* Ensure the result is wrapped as a call expression. */
21157 }
21158 else
21161 koenig_p,
21162 complain);
21165 {
21171 {
21175 }
21177 /* This also suppresses -Wredundant-move. */
21179 }
21182 }
21185 {
21192 {
21194 {
21199 }
21200 else
21201 {
21206 }
21208 }
21209 else
21210 {
21213 }
21218 }
21221 {
21226 input_location));
21227 }
21233 {
21234 tree object;
21235 tree object_type;
21236 tree member;
21237 tree r;
21241 /* Remember that there was a reference to this entity. */
21252 else
21259 {
21262 }
21264 {
21266 complain);
21270 }
21274 {
21276 {
21281 {
21284 }
21286 {
21291 }
21292 }
21293 }
21296 {
21297 /* Lookup the template functions now that we know what the
21298 scope is. */
21305 {
21308 args);
21309 member = (adjust_result_of_qualified_name_lookup
21311 object_type));
21312 }
21313 else
21314 {
21316 input_location);
21318 }
21319 }
21323 {
21325 {
21329 else
21332 }
21334 }
21338 complain);
21342 }
21349 {
21356 tree r;
21365 /* We do not want to process the index of aggregate
21366 initializers as they are identifier nodes which will be
21367 looked up by digest_init. */
21371 {
21374 }
21379 {
21381 /* An identifier index is looked up in the type
21382 being initialized, not the current scope. */
21387 {
21388 /* Substitute into the pack expansion. */
21390 in_decl);
21394 ;
21396 /* Just move the argument into place. */
21398 else
21399 {
21400 /* Update the length of the final CONSTRUCTOR
21401 arguments vector, and note that we will need to
21402 copy.*/
21405 }
21406 }
21407 else
21409 }
21412 {
21417 {
21419 {
21424 }
21425 else
21427 }
21428 }
21436 {
21441 }
21445 }
21448 {
21451 {
21454 }
21455 else
21456 {
21459 }
21460 }
21465 /* Fall through */
21468 {
21470 /* ??? We're doing a subset of finish_id_expression here. */
21472 /* Replace an evaluated use of the thread_local variable with
21473 a call to its wrapper. */
21479 /* If the original type was a reference, we'll be wrapped in
21480 the appropriate INDIRECT_REF. */
21483 }
21486 {
21490 }
21493 {
21494 tree object_ptr
21500 }
21507 {
21514 }
21517 {
21526 /* If the resulting list of expression statement is empty,
21527 fold it further into void_node. */
21532 }
21535 {
21537 {
21538 /* We don't have a full set of template arguments yet; don't touch
21539 the lambda at all. */
21542 }
21546 }
21554 else
21555 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21556 {
21560 }
21563 {
21568 complain));
21569 }
21572 {
21575 }
21578 /* No need to substitute further, a RANGE_EXPR will always be built
21579 with constant operands. */
21585 /* We need to do this here as well as in tsubst_copy so we get the
21586 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21589 /* fallthrough. */
21592 /* Handle Objective-C++ constructs, if appropriate. */
21593 {
21594 tree subst
21598 }
21600 }
21602 #undef RECUR
21603 #undef RETURN
21604 out:
21607 }
21609 /* Verify that the instantiated ARGS are valid. For type arguments,
21610 make sure that the type's linkage is ok. For non-type arguments,
21611 make sure they are constants if they are integral or enumerations.
21612 Emit an error under control of COMPLAIN, and return TRUE on error. */
21614 static bool
21616 {
21620 {
21630 }
21632 {
21633 /* [basic.link]: A name with no linkage (notably, the name
21634 of a class or enumeration declared in a local scope)
21635 shall not be used to declare an entity with linkage.
21636 This implies that names with no linkage cannot be used as
21637 template arguments
21639 DR 757 relaxes this restriction for C++0x. */
21644 {
21645 /* DR 488 makes use of a type with no linkage cause
21646 type deduction to fail. */
21648 {
21651 else
21654 }
21656 }
21657 /* In order to avoid all sorts of complications, we do not
21658 allow variably-modified types as template arguments. */
21660 {
21664 }
21665 }
21666 /* Class template and alias template arguments should be OK. */
21668 ;
21669 /* A non-type argument of integral or enumerated type must be a
21670 constant. */
21675 {
21679 }
21681 }
21683 static bool
21685 {
21690 {
21693 }
21697 }
21699 /* We're out of SFINAE context now, so generate diagnostics for the access
21700 errors we saw earlier when instantiating D from TMPL and ARGS. */
21702 static void
21704 {
21716 }
21718 /* Instantiate the indicated variable, function, or alias template TMPL with
21719 the template arguments in TARG_PTR. */
21721 tree
21723 {
21727 tree fndecl;
21728 tree gen_tmpl;
21729 tree spec;
21740 /* If this function is a clone, handle it specially. */
21742 {
21743 tree spec;
21744 tree clone;
21746 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21747 DECL_CLONED_FUNCTION. */
21753 /* Look for the clone. */
21757 /* We should always have found the clone by now. */
21760 }
21765 /* Check to see if we already have this specialization. */
21769 /* targ_ptr only has the innermost template args, so add the outer ones
21770 from tmpl, which could be either a partial instantiation or gen_tmpl (in
21771 the case of a non-dependent call within a template definition). */
21772 targ_ptr = (add_outermost_template_args
21774 targ_ptr));
21776 /* It would be nice to avoid hashing here and then again in tsubst_decl,
21777 but it doesn't seem to be on the hot path. */
21781 || ((fndecl
21787 {
21789 {
21793 }
21795 }
21798 complain))
21801 /* We are building a FUNCTION_DECL, during which the access of its
21802 parameters and return types have to be checked. However this
21803 FUNCTION_DECL which is the desired context for access checking
21804 is not built yet. We solve this chicken-and-egg problem by
21805 deferring all checks until we have the FUNCTION_DECL. */
21808 /* Instantiation of the function happens in the context of the function
21809 template, not the context of the overload resolution we're doing. */
21811 /* If there are dependent arguments, e.g. because we're doing partial
21812 ordering, make sure processing_template_decl stays set. */
21816 {
21817 tree ctx;
21819 /* If the context of the partially instantiated template is
21820 already non-dependent, then we might as well use it. */
21822 else
21826 }
21832 {
21833 /* We need to determine if we're using a partial or explicit
21834 specialization now, because the type of the variable could be
21835 different. */
21841 {
21846 }
21847 }
21849 /* Substitute template parameters to obtain the specialization. */
21857 {
21860 }
21862 /* The DECL_TI_TEMPLATE should always be the immediate parent
21863 template, not the most general template. */
21869 /* Now we know the specialization, compute access previously
21870 deferred. Do no access control for inheriting constructors,
21871 as we already checked access for the inherited constructor. */
21874 {
21879 }
21882 /* If we've just instantiated the main entry point for a function,
21883 instantiate all the alternate entry points as well. We do this
21884 by cloning the instantiation of the main entry point, not by
21885 instantiating the template clones. */
21891 {
21893 {
21894 /* Remember to reinstantiate when we're out of SFINAE so the user
21895 can see the errors. */
21897 }
21899 }
21902 }
21904 /* Instantiate the alias template TMPL with ARGS. Also push a template
21905 instantiation level, which instantiate_template doesn't do because
21906 functions and variables have sufficient context established by the
21907 callers. */
21909 static tree
21911 {
21918 /* FIXME check for satisfaction in check_instantiated_args. */
21922 {
21924 {
21925 auto_diagnostic_group d;
21928 }
21930 }
21938 {
21939 /* An alias template specialization can be dependent
21940 even if its underlying type is not. */
21943 /* Sometimes a dependent alias spec is equivalent to its expansion,
21944 sometimes not. So always use structural_comptypes. */
21946 }
21949 }
21951 /* PARM is a template parameter pack for FN. Returns true iff
21952 PARM is used in a deducible way in the argument list of FN. */
21954 static bool
21956 {
21959 {
21961 tree packs;
21967 {
21968 /* The template parameter pack is used in a function parameter
21969 pack. If this is the end of the parameter list, the
21970 template parameter pack is deducible. */
21973 else
21974 /* Otherwise, not. Well, it could be deduced from
21975 a non-pack parameter, but doing so would end up with
21976 a deduction mismatch, so don't bother. */
21978 }
21979 }
21980 /* The template parameter pack isn't used in any function parameter
21981 packs, but it might be used deeper, e.g. tuple<Args...>. */
21983 }
21985 /* Subroutine of fn_type_unification: check non-dependent parms for
21986 convertibility. */
21988 static int
21992 {
21993 /* Non-constructor methods need to leave a conversion for 'this', which
21994 isn't included in nargs here. */
22000 {
22006 /* For a function parameter pack that occurs at the end of the
22007 parameter-declaration-list, the type A of each remaining
22008 argument of the call is compared with the type P of the
22009 declarator-id of the function parameter pack. */
22015 /* For a function parameter pack that does not occur at the
22016 end of the parameter-declaration-list, the type of the
22017 parameter pack is a non-deduced context. */
22021 {
22029 }
22032 }
22035 }
22037 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22038 NARGS elements of the arguments that are being used when calling
22039 it. TARGS is a vector into which the deduced template arguments
22040 are placed.
22042 Returns either a FUNCTION_DECL for the matching specialization of FN or
22043 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22044 true, diagnostics will be printed to explain why it failed.
22046 If FN is a conversion operator, or we are trying to produce a specific
22047 specialization, RETURN_TYPE is the return type desired.
22049 The EXPLICIT_TARGS are explicit template arguments provided via a
22050 template-id.
22052 The parameter STRICT is one of:
22054 DEDUCE_CALL:
22055 We are deducing arguments for a function call, as in
22056 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22057 deducing arguments for a call to the result of a conversion
22058 function template, as in [over.call.object].
22060 DEDUCE_CONV:
22061 We are deducing arguments for a conversion function, as in
22062 [temp.deduct.conv].
22064 DEDUCE_EXACT:
22065 We are deducing arguments when doing an explicit instantiation
22066 as in [temp.explicit], when determining an explicit specialization
22067 as in [temp.expl.spec], or when taking the address of a function
22068 template, as in [temp.deduct.funcaddr]. */
22070 tree
22072 tree explicit_targs,
22073 tree targs,
22076 tree return_type,
22077 unification_kind_t strict,
22082 {
22083 tree parms;
22084 tree fntype;
22089 /* type_unification_real will pass back any access checks from default
22090 template argument substitution. */
22092 /* We don't have all the template args yet. */
22105 full_targs = (add_outermost_template_args
22107 targs));
22112 /* In C++0x, it's possible to have a function template whose type depends
22113 on itself recursively. This is most obvious with decltype, but can also
22114 occur with enumeration scope (c++/48969). So we need to catch infinite
22115 recursion and reject the substitution at deduction time; this function
22116 will return error_mark_node for any repeated substitution.
22118 This also catches excessive recursion such as when f<N> depends on
22119 f<N-1> across all integers, and returns error_mark_node for all the
22120 substitutions back up to the initial one.
22122 This is, of course, not reentrant. */
22131 {
22132 /* [temp.deduct]
22134 The specified template arguments must match the template
22135 parameters in kind (i.e., type, nontype, template), and there
22136 must not be more arguments than there are parameters;
22137 otherwise type deduction fails.
22139 Nontype arguments must match the types of the corresponding
22140 nontype template parameters, or must be convertible to the
22141 types of the corresponding nontype parameters as specified in
22142 _temp.arg.nontype_, otherwise type deduction fails.
22144 All references in the function type of the function template
22145 to the corresponding template parameters are replaced by the
22146 specified template argument values. If a substitution in a
22147 template parameter or in the function type of the function
22148 template results in an invalid type, type deduction fails. */
22159 explicit_targs);
22161 /* Adjust any explicit template arguments before entering the
22162 substitution context. */
22163 explicit_targs
22170 /* Substitute the explicit args into the function type. This is
22171 necessary so that, for instance, explicitly declared function
22172 arguments can match null pointed constants. If we were given
22173 an incomplete set of explicit args, we must not do semantic
22174 processing during substitution as we could create partial
22175 instantiations. */
22177 {
22182 /* Dig out the actual parm. */
22185 {
22188 }
22190 {
22193 }
22196 /* No explicit argument for this template parameter. */
22199 {
22200 /* Mark the argument pack as "incomplete". We could
22201 still deduce more arguments during unification.
22202 We remove this mark in type_unification_real. */
22207 /* We have some incomplete argument packs. */
22209 }
22210 }
22213 {
22215 {
22218 }
22221 /* Ignore any access checks; we'll see them again in
22222 instantiate_template and they might have the wrong
22223 access path at this point. */
22234 }
22236 /* Place the explicitly specified arguments in TARGS. */
22242 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22244 }
22247 {
22253 }
22258 /* Never do unification on the 'this' parameter. */
22262 {
22263 /* We're deducing for a call to the result of a template conversion
22264 function. The parms we really want are in return_type. */
22268 }
22270 {
22272 }
22274 /* We allow incomplete unification without an error message here
22275 because the standard doesn't seem to explicitly prohibit it. Our
22276 callers must be ready to deal with unification failures in any
22277 event. */
22279 /* If we aren't explaining yet, push tinst context so we can see where
22280 any errors (e.g. from class instantiations triggered by instantiation
22281 of default template arguments) come from. If we are explaining, this
22282 context is redundant. */
22284 {
22287 }
22297 /* Now that we have bindings for all of the template arguments,
22298 ensure that the arguments deduced for the template template
22299 parameters have compatible template parameter lists. We cannot
22300 check this property before we have deduced all template
22301 arguments, because the template parameter types of a template
22302 template parameter might depend on prior template parameters
22303 deduced after the template template parameter. The following
22304 ill-formed example illustrates this issue:
22306 template<typename T, template<T> class C> void f(C<5>, T);
22308 template<int N> struct X {};
22310 void g() {
22311 f(X<5>(), 5l); // error: template argument deduction fails
22312 }
22314 The template parameter list of 'C' depends on the template type
22315 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22316 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22317 time that we deduce 'C'. */
22320 {
22323 }
22325 deduced:
22327 /* CWG2369: Check satisfaction before non-deducible conversions. */
22329 {
22333 }
22335 /* DR 1391: All parameters have args, now check non-dependent parms for
22336 convertibility. We don't do this if all args were explicitly specified,
22337 as the standard says that we substitute explicit args immediately. */
22343 /* All is well so far. Now, check:
22345 [temp.deduct]
22347 When all template arguments have been deduced, all uses of
22348 template parameters in nondeduced contexts are replaced with
22349 the corresponding deduced argument values. If the
22350 substitution results in an invalid type, as described above,
22351 type deduction fails. */
22353 {
22356 }
22358 /* Also collect access checks from the instantiation. */
22371 /* Now perform any access checks encountered during substitution. */
22378 /* If we're looking for an exact match, check that what we got
22379 is indeed an exact match. It might not be if some template
22380 parameters are used in non-deduced contexts. But don't check
22381 for an exact match if we have dependent template arguments;
22382 in that case we're doing partial ordering, and we already know
22383 that we have two candidates that will provide the actual type. */
22385 {
22389 tree sarg
22395 {
22399 }
22401 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22402 doesn't contain the trailing void, and conv fns are always (). */
22404 {
22408 }
22409 }
22411 /* After doing deduction with the inherited constructor, actually return an
22412 instantiation of the inheriting constructor. */
22418 fail:
22421 {
22423 /* Reset once we're all the way out. */
22425 }
22428 }
22430 /* Returns true iff PARM is a forwarding reference in the context of
22431 template argument deduction for TMPL. */
22433 static bool
22435 {
22436 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22437 cv-unqualified template parameter ..." */
22442 {
22444 /* [temp.deduct.call], "... that does not represent a template parameter
22445 of a class template (during class template argument deduction)." */
22449 {
22450 /* Since the template parameters of a synthesized guide consist of
22451 the template parameters of the class template followed by those of
22452 the constructor (if any), we can tell if PARM represents a template
22453 parameter of the class template by comparing its index with the
22454 arity of the class template. */
22459 }
22461 }
22463 }
22465 /* Adjust types before performing type deduction, as described in
22466 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22467 sections are symmetric. PARM is the type of a function parameter
22468 or the return type of the conversion function. ARG is the type of
22469 the argument passed to the call, or the type of the value
22470 initialized with the result of the conversion function.
22471 ARG_EXPR is the original argument expression, which may be null. */
22473 static int
22475 unification_kind_t strict,
22478 tree arg_expr)
22479 {
22483 {
22488 /* Swap PARM and ARG throughout the remainder of this
22489 function; the handling is precisely symmetric since PARM
22490 will initialize ARG rather than vice versa. */
22495 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22496 too, but here handle it by stripping the reference from PARM
22497 rather than by adding it to ARG. */
22502 /* Nothing else to do in this case. */
22507 }
22510 {
22511 /* [temp.deduct.call]
22513 If P is not a reference type:
22515 --If A is an array type, the pointer type produced by the
22516 array-to-pointer standard conversion (_conv.array_) is
22517 used in place of A for type deduction; otherwise,
22519 --If A is a function type, the pointer type produced by
22520 the function-to-pointer standard conversion
22521 (_conv.func_) is used in place of A for type deduction;
22522 otherwise,
22524 --If A is a cv-qualified type, the top level
22525 cv-qualifiers of A's type are ignored for type
22526 deduction. */
22531 else
22533 }
22535 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22536 an lvalue, the type 'lvalue reference to A' is used in place of A for
22537 type deduction." */
22540 /* try_one_overload doesn't provide an arg_expr, but
22541 functions are always lvalues. */
22545 /* [temp.deduct.call]
22547 If P is a cv-qualified type, the top level cv-qualifiers
22548 of P's type are ignored for type deduction. If P is a
22549 reference type, the type referred to by P is used for
22550 type deduction. */
22553 {
22556 }
22558 /* DR 322. For conversion deduction, remove a reference type on parm
22559 too (which has been swapped into ARG). */
22564 }
22566 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22567 template which doesn't contain any deducible template parameters; check if
22568 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22569 unify_one_argument. */
22571 static int
22575 {
22576 tree type;
22580 else
22588 {
22591 }
22593 {
22597 /* Avoid recalculating this in add_function_candidate. */
22598 ok = (*conv_p
22600 else
22604 }
22608 else
22610 }
22614 /* Returns true iff the expression EXPR is one from which a template
22615 argument can be deduced. In other words, if it's an undecorated
22616 use of a template non-type parameter. */
22618 static bool
22620 {
22621 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22627 }
22629 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22630 deducible way; that is, if it has a max value of <PARM> - 1. */
22632 static bool
22634 {
22643 }
22645 /* Returns true iff the template arguments ARGS use a template parameter
22646 in a deducible way. */
22648 static bool
22650 {
22652 {
22656 else
22657 {
22664 else
22666 }
22669 }
22671 }
22673 /* Returns true iff TYPE contains any deducible references to template
22674 parameters, as per 14.8.2.5. */
22676 static bool
22678 {
22682 /* T
22683 cv-list T
22684 TT<T>
22685 TT<i>
22686 TT<> */
22691 /* T*
22692 T&
22693 T&& */
22697 /* T[integer-constant ]
22698 type [i] */
22703 /* T type ::*
22704 type T::*
22705 T T::*
22706 T (type ::*)()
22707 type (T::*)()
22708 type (type ::*)(T)
22709 type (T::*)(T)
22710 T (type ::*)(T)
22711 T (T::*)()
22712 T (T::*)(T) */
22715 || (uses_deducible_template_parms
22718 /* template-name <T> (where template-name refers to a class template)
22719 template-name <i> (where template-name refers to a class template) */
22726 /* type (T)
22727 T()
22728 T(T) */
22730 {
22744 }
22747 }
22749 /* Subroutine of type_unification_real and unify_pack_expansion to
22750 handle unification of a single P/A pair. Parameters are as
22751 for those functions. */
22753 static int
22757 {
22764 /* We can't deduce anything from this, but we might get all the
22765 template args from other function args. */
22768 /* Implicit conversions (Clause 4) will be performed on a function
22769 argument to convert it to the type of the corresponding function
22770 parameter if the parameter type contains no template-parameters that
22771 participate in template argument deduction. */
22774 /* For function parameters with no deducible template parameters,
22775 just return. We'll check non-dependent conversions later. */
22779 {
22781 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
22782 | UNIFY_ALLOW_MORE_CV_QUAL
22796 }
22798 /* We only do these transformations if this is the top-level
22799 parameter_type_list in a call or declaration matching; in other
22800 situations (nested function declarators, template argument lists) we
22801 won't be comparing a type to an expression, and we don't do any type
22802 adjustments. */
22804 {
22806 {
22809 {
22810 /* [temp.deduct.type] A template-argument can be
22811 deduced from a pointer to function or pointer
22812 to member function argument if the set of
22813 overloaded functions does not contain function
22814 templates and at most one of a set of
22815 overloaded functions provides a unique
22816 match. */
22820 /* If a unique match was not found, this is a
22821 non-deduced context, so we still succeed. */
22823 }
22829 }
22833 }
22834 else
22839 /* For deduction from an init-list we need the actual list. */
22843 }
22845 /* for_each_template_parm callback that always returns 0. */
22847 static int
22849 {
22851 }
22853 /* for_each_template_parm any_fn callback to handle deduction of a template
22854 type argument from the type of an array bound. */
22856 static int
22858 {
22866 {
22872 }
22874 /* Keep walking. */
22876 }
22878 /* Try to deduce any not-yet-deduced template type arguments from the type of
22879 an array bound. This is handled separately from unify because 14.8.2.5 says
22880 "The type of a type parameter is only deduced from an array bound if it is
22881 not otherwise deduced." */
22883 static void
22885 {
22890 }
22892 /* Most parms like fn_type_unification.
22894 If SUBR is 1, we're being called recursively (to unify the
22895 arguments of a function or method parameter of a function
22896 template).
22898 CHECKS is a pointer to a vector of access checks encountered while
22899 substituting default template arguments. */
22901 static int
22903 tree full_targs,
22904 tree xparms,
22908 unification_kind_t strict,
22911 {
22916 tree parms;
22927 /* Reset the number of non-defaulted template arguments contained
22928 in TARGS. */
22931 again:
22936 /* Only fn_type_unification cares about terminal void. */
22943 {
22948 /* For a function parameter pack that occurs at the end of the
22949 parameter-declaration-list, the type A of each remaining
22950 argument of the call is compared with the type P of the
22951 declarator-id of the function parameter pack. */
22957 /* For a function parameter pack that does not occur at the
22958 end of the parameter-declaration-list, the type of the
22959 parameter pack is a non-deduced context. */
22966 explain_p))
22968 }
22973 {
22974 /* Unify the remaining arguments with the pack expansion type. */
22975 tree argvec;
22978 /* Allocate a TREE_VEC and copy in all of the arguments */
22983 /* Copy the parameter into parmvec. */
22989 /* Advance to the end of the list of parameters. */
22991 }
22993 /* Fail if we've reached the end of the parm list, and more args
22994 are present, and the parm list isn't variadic. */
22997 /* Fail if parms are left and they don't have default values and
22998 they aren't all deduced as empty packs (c++/57397). This is
22999 consistent with sufficient_parms_p. */
23002 {
23006 do
23007 {
23010 count++;
23012 }
23016 type_pack_p);
23017 }
23020 {
23021 tsubst_flags_t complain = (explain_p
23022 ? tf_warning_or_error
23027 {
23031 /* Clear the "incomplete" flags on all argument packs now so that
23032 substituting them into later default arguments works. */
23034 {
23037 }
23045 {
23050 }
23052 /* If this is an undeduced nontype parameter that depends on
23053 a type parameter, try another pass; its type may have been
23054 deduced from a later argument than the one from which
23055 this parameter can be deduced. */
23060 {
23063 }
23065 /* Core issue #226 (C++0x) [temp.deduct]:
23067 If a template argument has not been deduced, its
23068 default template argument, if any, is used.
23070 When we are in C++98 mode, TREE_PURPOSE will either
23071 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23072 to explicitly check cxx_dialect here. */
23074 /* OK, there is a default argument. Wait until after the
23075 conversion check to do substitution. */
23078 /* If the type parameter is a parameter pack, then it will
23079 be deduced to an empty parameter pack. */
23081 {
23082 tree arg;
23085 {
23088 }
23089 else
23096 }
23099 }
23101 /* Now substitute into the default template arguments. */
23103 {
23120 {
23121 /* The type of this non-type parameter depends on undeduced
23122 parameters. Don't try to use its default argument yet,
23123 since we might deduce an argument for it on the next pass,
23124 but do check whether the arguments we already have cause
23125 substitution failure, so that that happens before we try
23126 later default arguments (78489). */
23129 NULL_TREE);
23133 else
23135 }
23136 else
23137 {
23138 /* Even if the call is happening in template context, getting
23139 here means it's non-dependent, and a default argument is
23140 considered a separate definition under [temp.decls], so we can
23141 do this substitution without processing_template_decl. This
23142 is important if the default argument contains something that
23143 might be instantiation-dependent like access (87480). */
23144 processing_template_decl_sentinel s;
23147 {
23148 /* First instatiate in template context, in case we still
23149 depend on undeduced template parameters. */
23152 NULL_TREE);
23156 /* We replaced all the tparms, substitute again out of
23157 template context. */
23159 }
23162 NULL_TREE);
23169 else
23171 }
23180 {
23182 /* The position of the first default template argument,
23183 is also the number of non-defaulted arguments in TARGS.
23184 Record that. */
23187 }
23188 }
23192 }
23198 }
23200 /* Subroutine of type_unification_real. Args are like the variables
23201 at the call site. ARG is an overloaded function (or template-id);
23202 we try deducing template args from each of the overloads, and if
23203 only one succeeds, we go with that. Modifies TARGS and returns
23204 true on success. */
23206 static bool
23208 tree targs,
23209 tree parm,
23210 tree arg,
23211 unification_kind_t strict,
23214 {
23221 {
23224 }
23225 else
23229 /* Handle `&x' where `x' is some static or non-static member
23230 function name. */
23236 /* Strip baselink information. */
23241 {
23242 /* If we got some explicit template args, we need to plug them into
23243 the affected templates before we try to unify, in case the
23244 explicit args will completely resolve the templates in question. */
23251 {
23262 {
23267 {
23268 /* Instantiate the function to deduce its return type. */
23272 }
23281 {
23284 }
23285 }
23288 }
23289 /* If no templates (or more than one) are fully resolved by the
23290 explicit arguments, this template-id is a non-deduced context; it
23291 could still be OK if we deduce all template arguments for the
23292 enclosing call through other arguments. */
23295 }
23297 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23298 -- but the deduction does not succeed because the expression is
23299 not just the function on its own. */
23301 else
23303 {
23308 {
23311 }
23312 }
23314 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23315 to function or pointer to member function argument if the set of
23316 overloaded functions does not contain function templates and at most
23317 one of a set of overloaded functions provides a unique match.
23319 So if we found multiple possibilities, we return success but don't
23320 deduce anything. */
23323 {
23327 {
23332 /* Don't forget explicit template arguments in a pack. */
23336 }
23337 }
23342 }
23344 /* Core DR 115: In contexts where deduction is done and fails, or in
23345 contexts where deduction is not done, if a template argument list is
23346 specified and it, along with any default template arguments, identifies
23347 a single function template specialization, then the template-id is an
23348 lvalue for the function template specialization. */
23350 tree
23352 {
23365 {
23368 }
23370 {
23373 }
23375 {
23378 }
23381 {
23385 /* If we got some explicit template args, we need to plug them into
23386 the affected templates before we try to unify, in case the
23387 explicit args will completely resolve the templates in question. */
23395 {
23406 {
23409 {
23412 }
23415 {
23418 }
23419 }
23420 }
23422 {
23430 {
23431 tree base
23434 }
23438 }
23440 /* There were no good options and at least one bad one, so let the
23441 user know what the problem is. */
23443 }
23445 }
23447 /* As above, but error out if the expression remains overloaded. */
23449 tree
23451 {
23454 {
23458 }
23460 }
23462 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23463 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23464 different overloads deduce different arguments for a given parm.
23465 ADDR_P is true if the expression for which deduction is being
23466 performed was of the form "& fn" rather than simply "fn".
23468 Returns 1 on success. */
23470 static int
23472 tree orig_targs,
23473 tree targs,
23474 tree parm,
23475 tree arg,
23476 unification_kind_t strict,
23480 {
23482 tree tempargs;
23488 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23489 to function or pointer to member function argument if the set of
23490 overloaded functions does not contain function templates and at most
23491 one of a set of overloaded functions provides a unique match.
23493 So if this is a template, just return success. */
23506 /* We don't copy orig_targs for this because if we have already deduced
23507 some template args from previous args, unify would complain when we
23508 try to deduce a template parameter for the same argument, even though
23509 there isn't really a conflict. */
23516 /* First make sure we didn't deduce anything that conflicts with
23517 explicitly specified args. */
23519 {
23526 /* Since we're unifying against ourselves, we will fill in
23527 template args used in the function parm list with our own
23528 template parms. Discard them. */
23531 {
23532 /* Check that the argument at each index of the deduced argument pack
23533 is equivalent to the corresponding explicitly specified argument.
23534 We may have deduced more arguments than were explicitly specified,
23535 and that's OK. */
23537 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23538 that's wrong if we deduce the same argument pack from multiple
23539 function arguments: it's only incomplete the first time. */
23552 }
23555 }
23558 {
23563 }
23566 }
23568 /* PARM is a template class (perhaps with unbound template
23569 parameters). ARG is a fully instantiated type. If ARG can be
23570 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23571 TARGS are as for unify. */
23573 static tree
23576 {
23585 /* We need to make a new template argument vector for the call to
23586 unify. If we used TARGS, we'd clutter it up with the result of
23587 the attempted unification, even if this class didn't work out.
23588 We also don't want to commit ourselves to all the unifications
23589 we've already done, since unification is supposed to be done on
23590 an argument-by-argument basis. In other words, consider the
23591 following pathological case:
23593 template <int I, int J, int K>
23594 struct S {};
23596 template <int I, int J>
23597 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23599 template <int I, int J, int K>
23600 void f(S<I, J, K>, S<I, I, I>);
23602 void g() {
23603 S<0, 0, 0> s0;
23604 S<0, 1, 2> s2;
23606 f(s0, s2);
23607 }
23609 Now, by the time we consider the unification involving `s2', we
23610 already know that we must have `f<0, 0, 0>'. But, even though
23611 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23612 because there are two ways to unify base classes of S<0, 1, 2>
23613 with S<I, I, I>. If we kept the already deduced knowledge, we
23614 would reject the possibility I=1. */
23622 else
23632 }
23634 /* Given a template type PARM and a class type ARG, find the unique
23635 base type in ARG that is an instance of PARM. We do not examine
23636 ARG itself; only its base-classes. If there is not exactly one
23637 appropriate base class, return NULL_TREE. PARM may be the type of
23638 a partial specialization, as well as a plain template type. Used
23639 by unify. */
23641 static enum template_base_result
23644 {
23646 tree binfo;
23652 {
23653 /* The type could not be completed. */
23656 }
23658 /* Walk in inheritance graph order. The search order is not
23659 important, and this avoids multiple walks of virtual bases. */
23661 {
23666 {
23667 /* If there is more than one satisfactory baseclass, then:
23669 [temp.deduct.call]
23671 If they yield more than one possible deduced A, the type
23672 deduction fails.
23674 applies. */
23676 {
23677 /* [temp.deduct.call]/4.3: If there is a class C that is a
23678 (direct or indirect) base class of D and derived (directly or
23679 indirectly) from a class B and that would be a valid deduced
23680 A, the deduced A cannot be B or pointer to B, respectively. */
23682 /* Ignore r. */
23686 else
23687 {
23690 }
23691 }
23694 }
23695 }
23699 }
23701 /* Returns the level of DECL, which declares a template parameter. */
23703 static int
23705 {
23707 {
23717 }
23719 }
23721 /* Decide whether ARG can be unified with PARM, considering only the
23722 cv-qualifiers of each type, given STRICT as documented for unify.
23723 Returns nonzero iff the unification is OK on that basis. */
23725 static int
23727 {
23733 {
23734 /* Although a CVR qualifier is ignored when being applied to a
23735 substituted template parameter ([8.3.2]/1 for example), that
23736 does not allow us to unify "const T" with "int&" because both
23737 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23738 It is ok when we're allowing additional CV qualifiers
23739 at the outer level [14.8.2.1]/3,1st bullet. */
23748 }
23759 }
23761 /* Determines the LEVEL and INDEX for the template parameter PARM. */
23762 void
23764 {
23768 {
23771 }
23772 else
23773 {
23776 }
23777 }
23779 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
23780 do { \
23781 if (unify (TP, TA, P, A, S, EP)) \
23782 return 1; \
23783 } while (0)
23785 /* Unifies the remaining arguments in PACKED_ARGS with the pack
23786 expansion at the end of PACKED_PARMS. Returns 0 if the type
23787 deduction succeeds, 1 otherwise. STRICT is the same as in
23788 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
23789 function call argument list. We'll need to adjust the arguments to make them
23790 types. SUBR tells us if this is from a recursive call to
23791 type_unification_real, or for comparing two template argument
23792 lists. */
23794 static int
23798 {
23799 tree parm
23805 /* Add in any args remembered from an earlier partial instantiation. */
23813 /* Determine the parameter packs we will be deducing from the
23814 pattern, and record their current deductions. */
23817 {
23821 /* Only template parameter packs can be deduced, not e.g. function
23822 parameter packs or __bases or __integer_pack. */
23826 /* Determine the index and level of this parameter pack. */
23831 /* Keep track of the parameter packs and their corresponding
23832 argument packs. */
23835 }
23837 /* Loop through all of the arguments that have not yet been
23838 unified and unify each with the pattern. */
23840 {
23841 tree parm;
23845 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
23846 or the element of its argument pack at the current index if
23847 this argument was explicitly specified. */
23849 {
23858 {
23861 }
23863 }
23865 /* If we had explicit template arguments, substitute them into the
23866 pattern before deduction. */
23868 {
23869 /* Some arguments might still be unspecified or dependent. */
23877 NULL_TREE);
23882 }
23883 else
23886 /* Unify the pattern with the current argument. */
23888 explain_p))
23891 /* For each parameter pack, collect the deduced value. */
23893 {
23899 }
23900 }
23902 /* Verify that the results of unification with the parameter packs
23903 produce results consistent with what we've seen before, and make
23904 the deduced argument packs available. */
23906 {
23913 /* By default keep the original deduced argument pack.
23914 If necessary, more specific code is going to update the
23915 resulting deduced argument later down in this function. */
23919 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
23920 actually deduce anything. */
23928 {
23929 /* If we had fewer function args than explicit template args,
23930 just use the explicits. */
23935 }
23938 {
23939 tree result;
23940 /* Build the deduced *_ARGUMENT_PACK. */
23942 {
23945 }
23946 else
23951 /* Note the deduced argument packs for this parameter
23952 pack. */
23954 }
23958 {
23959 /* We only had the explicitly-provided arguments before, but
23960 now we have a complete set of arguments. */
23966 }
23967 else
23968 {
23972 /* During template argument deduction for the aggregate deduction
23973 candidate, the number of elements in a trailing parameter pack
23974 is only deduced from the number of remaining function
23975 arguments if it is not otherwise deduced. */
23982 /* Inconsistent unification of this parameter pack. */
23984 bad_old_arg,
23985 bad_new_arg);
23986 }
23987 }
23990 }
23992 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
23993 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
23994 parameters and return value are as for unify. */
23996 static int
24000 {
24001 tree parm_max;
24002 tree arg_max;
24006 /* Our representation of array types uses "N - 1" as the
24007 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24008 not an integer constant. We cannot unify arbitrarily
24009 complex expressions, so we eliminate the MINUS_EXPRs
24010 here. */
24014 {
24017 }
24021 {
24022 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24023 trying to unify the type of a variable with the type
24024 of a template parameter. For example:
24026 template <unsigned int N>
24027 void f (char (&) [N]);
24028 int g();
24029 void h(int i) {
24030 char a[g(i)];
24031 f(a);
24032 }
24034 Here, the type of the ARG will be "int [g(i)]", and
24035 may be a SAVE_EXPR, etc. */
24039 }
24041 /* If only one of the bounds used a MINUS_EXPR, compensate
24042 by adding one to the other bound. */
24045 integer_type_node,
24046 parm_max,
24047 integer_one_node);
24050 integer_type_node,
24051 arg_max,
24052 integer_one_node);
24056 }
24058 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24062 static pa_kind_t
24064 {
24073 else
24075 }
24077 /* Deduce the value of template parameters. TPARMS is the (innermost)
24078 set of template parameters to a template. TARGS is the bindings
24079 for those template parameters, as determined thus far; TARGS may
24080 include template arguments for outer levels of template parameters
24081 as well. PARM is a parameter to a template function, or a
24082 subcomponent of that parameter; ARG is the corresponding argument.
24083 This function attempts to match PARM with ARG in a manner
24084 consistent with the existing assignments in TARGS. If more values
24085 are deduced, then TARGS is updated.
24087 Returns 0 if the type deduction succeeds, 1 otherwise. The
24088 parameter STRICT is a bitwise or of the following flags:
24090 UNIFY_ALLOW_NONE:
24091 Require an exact match between PARM and ARG.
24092 UNIFY_ALLOW_MORE_CV_QUAL:
24093 Allow the deduced ARG to be more cv-qualified (by qualification
24094 conversion) than ARG.
24095 UNIFY_ALLOW_LESS_CV_QUAL:
24096 Allow the deduced ARG to be less cv-qualified than ARG.
24097 UNIFY_ALLOW_DERIVED:
24098 Allow the deduced ARG to be a template base class of ARG,
24099 or a pointer to a template base class of the type pointed to by
24100 ARG.
24101 UNIFY_ALLOW_INTEGER:
24102 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24103 case for more information.
24104 UNIFY_ALLOW_OUTER_LEVEL:
24105 This is the outermost level of a deduction. Used to determine validity
24106 of qualification conversions. A valid qualification conversion must
24107 have const qualified pointers leading up to the inner type which
24108 requires additional CV quals, except at the outer level, where const
24109 is not required [conv.qual]. It would be normal to set this flag in
24110 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24111 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24112 This is the outermost level of a deduction, and PARM can be more CV
24113 qualified at this point.
24114 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24115 This is the outermost level of a deduction, and PARM can be less CV
24116 qualified at this point. */
24118 static int
24121 {
24123 tree targ;
24124 tree tparm;
24126 tsubst_flags_t complain = (explain_p
24127 ? tf_warning_or_error
24130 /* I don't think this will do the right thing with respect to types.
24131 But the only case I've seen it in so far has been array bounds, where
24132 signedness is the only information lost, and I think that will be
24133 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24134 finish_id_expression_1, and are also OK. */
24142 /* We can't deduce anything from this, but we might get all the
24143 template args from other function args. */
24149 /* If PARM uses template parameters, then we can't bail out here,
24150 even if ARG == PARM, since we won't record unifications for the
24151 template parameters. We might need them if we're trying to
24152 figure out which of two things is more specialized. */
24156 /* Handle init lists early, so the rest of the function can assume
24157 we're dealing with a type. */
24159 {
24160 tree elttype;
24165 /* We can only deduce from an initializer list argument if the
24166 parameter is std::initializer_list or an array; otherwise this
24167 is a non-deduced context. */
24172 else
24173 {
24175 /* Deduction is defined in terms of a single type, so just punt
24176 on the (bizarre) std::initializer_list<T...>. */
24179 }
24184 /* If ELTTYPE has no deducible template parms, skip deduction from
24186 else
24188 {
24196 {
24200 /* It should only be possible to get here for a call. */
24202 elt_strict |= maybe_adjust_types_for_deduction
24205 }
24208 explain_p);
24209 }
24213 {
24214 /* Also deduce from the length of the initializer list. */
24221 }
24223 /* If the std::initializer_list<T> deduction worked, replace the
24224 deduced A with std::initializer_list<A>. */
24226 {
24231 }
24233 }
24235 /* If parm and arg aren't the same kind of thing (template, type, or
24236 expression), fail early. */
24240 /* Immediately reject some pairs that won't unify because of
24241 cv-qualification mismatches. */
24244 /* It is the elements of the array which hold the cv quals of an array
24245 type, and the elements might be template type parms. We'll check
24246 when we recurse. */
24248 /* We check the cv-qualifiers when unifying with template type
24249 parameters below. We want to allow ARG `const T' to unify with
24250 PARM `T' for example, when computing which of two templates
24251 is more specialized, for example. */
24265 {
24269 /* In a type which contains a nested-name-specifier, template
24270 argument values cannot be deduced for template parameters used
24271 within the nested-name-specifier. */
24283 /* The PARM is not one we're trying to unify. Just check
24284 to see if it matches ARG. */
24285 {
24290 else
24292 }
24299 /* Check for mixed types and values. */
24307 {
24310 {
24311 /* First try to match ARG directly. */
24313 explain_p);
24315 {
24316 /* Otherwise, look for a suitable base of ARG, as below. */
24323 }
24324 }
24325 /* ARG must be constructed from a template class or a template
24326 template parameter. */
24331 /* Deduce arguments T, i from TT<T> or TT<i>. */
24337 /* If the template is a template template parameter, use the
24338 TEMPLATE_TEMPLATE_PARM for matching. */
24341 /* Fall through to deduce template name. */
24342 }
24346 {
24347 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24349 /* Simple cases: Value already set, does match or doesn't. */
24354 }
24355 else
24356 {
24357 /* If PARM is `const T' and ARG is only `int', we don't have
24358 a match unless we are allowing additional qualification.
24359 If ARG is `const int' and PARM is just `T' that's OK;
24360 that binds `const int' to `T'. */
24365 /* Consider the case where ARG is `const volatile int' and
24366 PARM is `const T'. Then, T should be `volatile int'. */
24367 arg = cp_build_qualified_type
24372 /* Simple cases: Value already set, does match or doesn't. */
24378 /* Make sure that ARG is not a variable-sized array. (Note
24379 that were talking about variable-sized arrays (like
24380 `int[n]'), rather than arrays of unknown size (like
24381 `int[]').) We'll get very confused by such a type since
24382 the bound of the array is not constant, and therefore
24383 not mangleable. Besides, such types are not allowed in
24384 ISO C++, so we can do as we please here. We do allow
24385 them for 'auto' deduction, since that isn't ABI-exposed. */
24389 /* Strip typedefs as in convert_template_argument. */
24391 }
24393 /* If ARG is a parameter pack or an expansion, we cannot unify
24394 against it unless PARM is also a parameter pack. */
24399 /* If the argument deduction results is a METHOD_TYPE,
24400 then there is a problem.
24401 METHOD_TYPE doesn't map to any real C++ type the result of
24402 the deduction cannot be of that type. */
24416 {
24417 /* The PARM is not one we're trying to unify. Just check
24418 to see if it matches ARG. */
24424 }
24430 {
24434 /* We're deducing from an array bound, the type doesn't matter. */
24440 }
24442 /* [temp.deduct.type] If, in the declaration of a function template
24443 with a non-type template-parameter, the non-type
24444 template-parameter is used in an expression in the function
24445 parameter-list and, if the corresponding template-argument is
24446 deduced, the template-argument type shall match the type of the
24447 template-parameter exactly, except that a template-argument
24448 deduced from an array bound may be of any integral type.
24449 The non-type parameter might use already deduced type parameters. */
24452 /* We don't have enough levels of args to do any substitution. This
24454 else
24455 {
24461 {
24466 }
24467 }
24471 /* Template-parameter dependent expression. Just accept it for now.
24472 It will later be processed in convert_template_argument. */
24473 ;
24477 /* OK. Ignore top-level quals here because a class-type template
24481 /* Convert the ARG to the type of PARM; the deduced non-type
24482 template argument must exactly match the types of the
24483 corresponding parameter. */
24486 {
24487 /* We haven't deduced the type of this parameter yet. */
24489 /* We deduce from array bounds in try_array_deduction. */
24492 {
24493 /* Deduce it from the non-type argument. As above, ignore
24494 top-level quals here too. */
24499 /* Now check whether the type of this parameter is still
24500 dependent, and give up if so. */
24506 }
24507 else
24508 /* Try again later. */
24510 }
24511 else
24514 /* If ARG is a parameter pack or an expansion, we cannot unify
24515 against it unless PARM is also a parameter pack. */
24520 {
24523 }
24528 {
24529 /* A pointer-to-member constant can be unified only with
24530 another constant. */
24534 /* Just unify the class member. It would be useless (and possibly
24535 wrong, depending on the strict flags) to unify also
24536 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24537 arg refer to the same variable, even if through different
24538 classes. For instance:
24540 struct A { int x; };
24541 struct B : A { };
24543 Unification of &A::x and &B::x must succeed. */
24546 }
24549 {
24553 /* [temp.deduct.call]
24555 A can be another pointer or pointer to member type that can
24556 be converted to the deduced A via a qualification
24557 conversion (_conv.qual_).
24559 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24560 This will allow for additional cv-qualification of the
24561 pointed-to types if appropriate. */
24564 /* The derived-to-base conversion only persists through one
24565 level of pointers. */
24570 }
24603 /* We have already checked cv-qualification at the top of the
24604 function. */
24608 /* As far as unification is concerned, this wins. Later checks
24609 will invalidate it if necessary. */
24612 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24613 /* Type INTEGER_CST can come from ordinary constant template args. */
24625 {
24635 /* Check for pack expansions in the parameters. */
24637 {
24639 {
24641 /* We can unify against something with a trailing
24642 parameter pack. */
24644 else
24645 /* [temp.deduct.type]/9: If the template argument list of
24646 P contains a pack expansion that is not the last
24647 template argument, the entire template argument list
24648 is a non-deduced context. */
24650 }
24651 }
24653 /* If we don't have enough arguments to satisfy the parameters
24654 (not counting the pack expression at the end), or we have
24655 too many arguments for a parameter list that doesn't end in
24656 a pack expression, we can't unify. */
24662 /* Unify all of the parameters that precede the (optional)
24663 pack expression. */
24665 {
24670 }
24673 DEDUCE_EXACT,
24676 }
24684 {
24692 }
24697 {
24701 {
24702 /* First, we try to unify the PARM and ARG directly. */
24707 {
24708 /* Fallback to the special case allowed in
24709 [temp.deduct.call]:
24711 If P is a class, and P has the form
24712 template-id, then A can be a derived class of
24713 the deduced A. Likewise, if P is a pointer to
24714 a class of the form template-id, A can be a
24715 pointer to a derived class pointed to by the
24716 deduced A. */
24722 {
24723 /* Don't give the derived diagnostic if we're
24724 already dealing with the same template. */
24725 bool same_template
24731 }
24732 }
24733 }
24737 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24738 Then, we should unify `int' and `U'. */
24740 else
24741 /* There's no chance of unification succeeding. */
24746 }
24753 {
24756 tree a;
24762 /* CV qualifications for methods can never be deduced, they must
24763 match exactly. We need to check them explicitly here,
24764 because type_unification_real treats them as any other
24765 cv-qualified parameter. */
24767 && (!check_cv_quals_for_unify
24795 {
24807 }
24810 }
24813 /* Unify a pointer to member with a pointer to member function, which
24814 deduces the type of the member as a function type. */
24816 {
24817 /* Check top-level cv qualifiers */
24825 /* Determine the type of the function we are unifying against. */
24829 }
24848 /* Matched cases are handled by the ARG == PARM test above. */
24852 /* We might get a variable as a non-type template argument in parm if the
24853 corresponding parameter is type-dependent. Make any necessary
24854 adjustments based on whether arg is a reference. */
24858 {
24863 }
24864 /* Now use the normal expression code to check whether they match. */
24875 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
24876 or TRAIT_TYPE nodes. */
24880 /* Unification fails if we hit an error node. */
24885 {
24895 }
24896 /* FALLTHRU */
24899 /* An unresolved overload is a nondeduced context. */
24905 expr:
24906 /* We must be looking at an expression. This can happen with
24907 something like:
24909 template <int I>
24910 void foo(S<I>, S<I + 2>);
24912 or
24914 template<typename T>
24915 void foo(A<T, T{}>);
24917 This is a "non-deduced context":
24919 [deduct.type]
24921 The non-deduced contexts are:
24923 --A non-type template argument or an array bound in which
24924 a subexpression references a template parameter.
24926 In these cases, we assume deduction succeeded, but don't
24927 actually infer any unifications. */
24932 else
24934 }
24935 }
24936 #undef RECUR_AND_CHECK_FAILURE
24937 \f
24938 /* Note that DECL can be defined in this translation unit, if
24939 required. */
24941 static void
24943 {
24944 tree clone;
24948 }
24950 /* Called if RESULT is explicitly instantiated, or is a member of an
24951 explicitly instantiated class. */
24953 void
24955 {
24958 /* If this entity has already been written out, it's too late to
24959 make any modifications. */
24963 /* consteval functions are never emitted. */
24968 /* For anonymous namespace we don't need to do anything. */
24970 {
24973 }
24976 /* The TREE_PUBLIC flag for function declarations will have been
24977 set correctly by tsubst. */
24981 {
24984 }
24985 else
24986 {
24989 /* Always make artificials weak. */
24992 /* For WIN32 we also want to put explicit instantiations in
24993 linkonce sections. */
24998 /* If the function has already been instantiated, clear DECL_EXTERNAL,
24999 since start_preparsed_function wouldn't have if we had an earlier
25000 extern explicit instantiation. */
25002 }
25004 /* If EXTERN_P, then this function will not be emitted -- unless
25005 followed by an explicit instantiation, at which point its linkage
25006 will be adjusted. If !EXTERN_P, then this function will be
25007 emitted here. In neither circumstance do we want
25008 import_export_decl to adjust the linkage. */
25010 }
25012 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25013 important template arguments. If any are missing, we check whether
25014 they're important by using error_mark_node for substituting into any
25015 args that were used for partial ordering (the ones between ARGS and END)
25016 and seeing if it bubbles up. */
25018 static bool
25020 {
25024 {
25027 }
25029 {
25033 }
25035 }
25037 /* Given two function templates PAT1 and PAT2, return:
25039 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25040 -1 if PAT2 is more specialized than PAT1.
25041 0 if neither is more specialized.
25043 LEN indicates the number of parameters we should consider
25044 (defaulted parameters should not be considered).
25046 The 1998 std underspecified function template partial ordering, and
25047 DR214 addresses the issue. We take pairs of arguments, one from
25048 each of the templates, and deduce them against each other. One of
25049 the templates will be more specialized if all the *other*
25050 template's arguments deduce against its arguments and at least one
25051 of its arguments *does* *not* deduce against the other template's
25052 corresponding argument. Deduction is done as for class templates.
25053 The arguments used in deduction have reference and top level cv
25054 qualifiers removed. Iff both arguments were originally reference
25055 types *and* deduction succeeds in both directions, an lvalue reference
25056 wins against an rvalue reference and otherwise the template
25057 with the more cv-qualified argument wins for that pairing (if
25058 neither is more cv-qualified, they both are equal). Unlike regular
25059 deduction, after all the arguments have been deduced in this way,
25060 we do *not* verify the deduced template argument values can be
25061 substituted into non-deduced contexts.
25063 The logic can be a bit confusing here, because we look at deduce1 and
25064 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25065 can find template arguments for pat1 to make arg1 look like arg2, that
25066 means that arg2 is at least as specialized as arg1. */
25068 int
25070 {
25083 /* Remove the this parameter from non-static member functions. If
25084 one is a non-static member function and the other is not a static
25085 member function, remove the first parameter from that function
25086 also. This situation occurs for operator functions where we
25087 locate both a member function (with this pointer) and non-member
25088 operator (with explicit first operand). */
25090 {
25095 }
25097 {
25100 {
25101 len--;
25103 }
25104 }
25106 /* If only one is a conversion operator, they are unordered. */
25110 /* Consider the return type for a conversion function */
25112 {
25115 len++;
25116 }
25118 processing_template_decl++;
25124 /* Stop when an ellipsis is seen. */
25126 {
25137 {
25138 /* When both arguments are pack expansions, we need only
25139 unify the patterns themselves. */
25143 /* This is the last comparison we need to do. */
25145 }
25148 {
25152 }
25155 {
25159 }
25165 {
25171 /* Setup the parameter vector, which contains only ARG1. */
25174 /* Setup the argument vector, which contains the remaining
25175 arguments. */
25184 /* We cannot deduce in the other direction, because ARG1 is
25185 a pack expansion but ARG2 is not. */
25187 }
25189 {
25195 /* Setup the parameter vector, which contains only ARG1. */
25198 /* Setup the argument vector, which contains the remaining
25199 arguments. */
25208 /* We cannot deduce in the other direction, because ARG2 is
25209 a pack expansion but ARG1 is not.*/
25211 }
25213 else
25214 {
25215 /* The normal case, where neither argument is a pack
25216 expansion. */
25223 }
25225 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25226 arg2, then arg2 is not as specialized as arg1. */
25232 /* "If, for a given type, deduction succeeds in both directions
25233 (i.e., the types are identical after the transformations above)
25234 and both P and A were reference types (before being replaced with
25235 the type referred to above):
25236 - if the type from the argument template was an lvalue reference and
25237 the type from the parameter template was not, the argument type is
25238 considered to be more specialized than the other; otherwise,
25239 - if the type from the argument template is more cv-qualified
25240 than the type from the parameter template (as described above),
25241 the argument type is considered to be more specialized than the other;
25242 otherwise,
25243 - neither type is more specialized than the other." */
25246 {
25248 {
25251 else
25253 }
25255 {
25260 }
25261 }
25264 /* We've failed to deduce something in either direction.
25265 These must be unordered. */
25270 /* We have already processed all of the arguments in our
25271 handing of the pack expansion type. */
25276 }
25278 /* "In most cases, all template parameters must have values in order for
25279 deduction to succeed, but for partial ordering purposes a template
25280 parameter may remain without a value provided it is not used in the
25281 types being used for partial ordering."
25283 Thus, if we are missing any of the targs1 we need to substitute into
25284 origs1, then pat2 is not as specialized as pat1. This can happen when
25285 there is a nondeduced context. */
25291 processing_template_decl--;
25293 /* If both deductions succeed, the partial ordering selects the more
25294 constrained template. */
25295 /* P2113: If the corresponding template-parameters of the
25296 template-parameter-lists are not equivalent ([temp.over.link]) or if
25297 the function parameters that positionally correspond between the two
25298 templates are not of the same type, neither template is more
25299 specialized than the other. */
25304 {
25310 }
25312 /* All things being equal, if the next argument is a pack expansion
25313 for one function but not for the other, prefer the
25314 non-variadic function. FIXME this is bogus; see c++/41958. */
25318 {
25321 }
25327 else
25329 }
25331 /* Determine which of two partial specializations of TMPL is more
25332 specialized.
25334 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25335 to the first partial specialization. The TREE_PURPOSE is the
25336 innermost set of template parameters for the partial
25337 specialization. PAT2 is similar, but for the second template.
25339 Return 1 if the first partial specialization is more specialized;
25340 -1 if the second is more specialized; 0 if neither is more
25341 specialized.
25343 See [temp.class.order] for information about determining which of
25344 two templates is more specialized. */
25346 static int
25348 {
25349 tree targs;
25358 /* Just like what happens for functions, if we are ordering between
25359 different template specializations, we may encounter dependent
25360 types in the arguments, and we need our dependency check functions
25361 to behave correctly. */
25365 {
25368 }
25372 {
25375 }
25378 /* If both deductions succeed, the partial ordering selects the more
25379 constrained template. */
25383 /* In the case of a tie where at least one of the templates
25384 has a parameter pack at the end, the template with the most
25385 non-packed parameters wins. */
25387 && any_deductions
25390 {
25396 /* We don't count the pack expansion at the end. */
25406 }
25409 }
25411 /* Return the template arguments that will produce the function signature
25412 DECL from the function template FN, with the explicit template
25413 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25414 also match. Return NULL_TREE if no satisfactory arguments could be
25415 found. */
25417 static tree
25419 {
25423 tree decl_arg_types;
25426 tree arg;
25430 /* Never do unification on the 'this' parameter. */
25452 }
25454 /* Return the innermost template arguments that, when applied to a partial
25455 specialization SPEC_TMPL of TMPL, yield the ARGS.
25457 For example, suppose we have:
25459 template <class T, class U> struct S {};
25460 template <class T> struct S<T*, int> {};
25462 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25463 partial specialization and the ARGS will be {double*, int}. The resulting
25464 vector will be {double}, indicating that `T' is bound to `double'. */
25466 static tree
25468 {
25470 tree spec_args
25473 tree deduced_args;
25474 tree innermost_deduced_args;
25478 {
25482 innermost_deduced_args);
25483 }
25484 else
25488 again:
25497 {
25499 {
25505 }
25507 }
25510 {
25513 }
25515 /* Verify that nondeduced template arguments agree with the type
25516 obtained from argument deduction.
25518 For example:
25520 struct A { typedef int X; };
25521 template <class T, class U> struct C {};
25522 template <class T> struct C<T, typename T::X> {};
25524 Then with the instantiation `C<A, int>', we can deduce that
25525 `T' is `A' but unify () does not check whether `typename T::X'
25526 is `int'. */
25537 /* We only need to check the innermost arguments; the other
25538 arguments will always agree. */
25543 /* Now that we have bindings for all of the template arguments,
25544 ensure that the arguments deduced for the template template
25545 parameters have compatible template parameter lists. See the use
25546 of template_template_parm_bindings_ok_p in fn_type_unification
25547 for more information. */
25552 }
25554 // Compare two function templates T1 and T2 by deducing bindings
25555 // from one against the other. If both deductions succeed, compare
25556 // constraints to see which is more constrained.
25557 static int
25559 {
25564 {
25567 }
25570 {
25573 }
25575 // If both deductions succeed, then one may be more constrained.
25580 }
25582 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25583 Return the TREE_LIST node with the most specialized template, if
25584 any. If there is no most specialized template, the error_mark_node
25585 is returned.
25587 Note that this function does not look at, or modify, the
25588 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25589 returned is one of the elements of INSTANTIATIONS, callers may
25590 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25591 and retrieve it from the value returned. */
25593 tree
25595 {
25602 {
25608 {
25609 /* Equally specialized, move to next function. If there
25610 is no next function, nothing's most specialized. */
25615 }
25616 }
25619 /* Now verify that champ is better than everything earlier in the
25620 instantiation list. */
25623 {
25626 }
25627 }
25629 processing_template_decl--;
25635 }
25637 /* If DECL is a specialization of some template, return the most
25638 general such template. Otherwise, returns NULL_TREE.
25640 For example, given:
25642 template <class T> struct S { template <class U> void f(U); };
25644 if TMPL is `template <class U> void S<int>::f(U)' this will return
25645 the full template. This function will not trace past partial
25646 specializations, however. For example, given in addition:
25648 template <class T> struct S<T*> { template <class U> void f(U); };
25650 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25651 `template <class T> template <class U> S<T*>::f(U)'. */
25653 tree
25655 {
25657 {
25660 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25661 template friend, or a FIELD_DECL for a capture pack. */
25664 }
25666 /* Look for more and more general templates. */
25668 {
25669 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25670 (See cp-tree.h for details.) */
25679 /* Stop if we run into an explicitly specialized class template. */
25686 }
25689 }
25691 /* Return the most specialized of the template partial specializations
25692 which can produce TARGET, a specialization of some class or variable
25693 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
25694 a TEMPLATE_DECL node corresponding to the partial specialization, while
25695 the TREE_PURPOSE is the set of template arguments that must be
25696 substituted into the template pattern in order to generate TARGET.
25698 If the choice of partial specialization is ambiguous, a diagnostic
25699 is issued, and the error_mark_node is returned. If there are no
25700 partial specializations matching TARGET, then NULL_TREE is
25701 returned, indicating that the primary template should be used. */
25703 tree
25705 {
25707 tree t;
25708 tree champ;
25714 tree decl;
25716 {
25721 }
25723 {
25727 }
25729 {
25734 }
25735 else
25743 /* For determining which partial specialization to use, only the
25744 innermost args are interesting. */
25746 {
25749 }
25751 /* The caller hasn't called push_to_top_level yet, but we need
25752 get_partial_spec_bindings to be done in non-template context so that we'll
25753 fully resolve everything. */
25754 processing_template_decl_sentinel ptds;
25757 {
25760 tree spec_tmpl;
25762 {
25763 /* Substitute in the template args from the enclosing class. */
25769 }
25770 else
25775 {
25779 /* Keep the candidate only if the constraints are satisfied,
25780 or if we're not compiling with concepts. */
25783 {
25786 }
25787 }
25788 }
25798 {
25801 ;
25802 else
25803 {
25805 {
25808 {
25811 }
25812 }
25814 }
25815 }
25819 {
25822 {
25825 }
25826 }
25829 {
25836 else
25840 {
25845 }
25848 }
25851 }
25853 /* Explicitly instantiate DECL. */
25855 void
25857 {
25862 /* An error occurred, for which grokdeclarator has already issued
25863 an appropriate message. */
25866 {
25869 }
25871 {
25874 else
25877 }
25883 {
25884 /* There is an asymmetry here in the way VAR_DECLs and
25885 FUNCTION_DECLs are handled by grokdeclarator. In the case of
25886 the latter, the DECL we get back will be marked as a
25887 template instantiation, and the appropriate
25888 DECL_TEMPLATE_INFO will be set up. This does not happen for
25889 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
25890 should handle VAR_DECLs as it currently handles
25891 FUNCTION_DECLs. */
25893 {
25896 }
25899 {
25902 }
25904 {
25909 }
25910 }
25912 {
25915 }
25916 else
25919 /* Check for various error cases. Note that if the explicit
25920 instantiation is valid the RESULT will currently be marked as an
25921 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
25922 until we get here. */
25925 {
25926 /* DR 259 [temp.spec].
25928 Both an explicit instantiation and a declaration of an explicit
25929 specialization shall not appear in a program unless the explicit
25930 instantiation follows a declaration of the explicit specialization.
25932 For a given set of template parameters, if an explicit
25933 instantiation of a template appears after a declaration of an
25934 explicit specialization for that template, the explicit
25935 instantiation has no effect. */
25937 }
25939 {
25940 /* [temp.spec]
25942 No program shall explicitly instantiate any template more
25943 than once.
25945 We check DECL_NOT_REALLY_EXTERN so as not to complain when
25946 the first instantiation was `extern' and the second is not,
25947 and EXTERN_P for the opposite case. */
25950 /* If an "extern" explicit instantiation follows an ordinary
25951 explicit instantiation, the template is instantiated. */
25954 }
25956 {
25959 }
25961 {
25964 }
25967 ;
25969 {
25972 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
25975 }
25976 else
25984 }
25986 static void
25988 {
25994 {
25997 }
25998 }
26000 /* Perform an explicit instantiation of template class T. STORAGE, if
26001 non-null, is the RID for extern, inline or static. COMPLAIN is
26002 nonzero if this is called from the parser, zero if called recursively,
26003 since the standard is unclear (as detailed below). */
26005 void
26007 {
26009 {
26013 else
26016 }
26021 {
26024 t);
26026 }
26028 /* At most one of these will be true. */
26034 {
26036 {
26039 "ISO C++ 1998 forbids the use of %<extern%> on "
26041 }
26042 else
26044 "ISO C++ forbids the use of %qE"
26053 else
26055 storage);
26056 }
26059 /* DR 259 [temp.spec].
26061 Both an explicit instantiation and a declaration of an explicit
26062 specialization shall not appear in a program unless the
26063 explicit instantiation follows a declaration of the explicit
26064 specialization.
26066 For a given set of template parameters, if an explicit
26067 instantiation of a template appears after a declaration of an
26068 explicit specialization for that template, the explicit
26069 instantiation has no effect. */
26073 {
26074 /* We've already instantiated the template. */
26076 /* [temp.spec]
26078 No program shall explicitly instantiate any template more
26079 than once.
26081 If EXTERN_P then this is ok. */
26087 }
26095 /* In contrast to implicit instantiation, where only the
26096 declarations, and not the definitions, of members are
26097 instantiated, we have here:
26099 [temp.explicit]
26101 An explicit instantiation that names a class template
26102 specialization is also an explicit instantiation of the same
26103 kind (declaration or definition) of each of its members (not
26104 including members inherited from base classes and members
26105 that are templates) that has not been previously explicitly
26106 specialized in the translation unit containing the explicit
26107 instantiation, provided that the associated constraints, if
26108 any, of that member are satisfied by the template arguments
26109 of the explicit instantiation. */
26113 && !static_p
26117 {
26122 }
26124 {
26130 }
26131 }
26133 /* Given a function DECL, which is a specialization of TMPL, modify
26134 DECL to be a re-instantiation of TMPL with the same template
26135 arguments. TMPL should be the template into which tsubst'ing
26136 should occur for DECL, not the most general template.
26138 One reason for doing this is a scenario like this:
26140 template <class T>
26141 void f(const T&, int i);
26143 void g() { f(3, 7); }
26145 template <class T>
26146 void f(const T& t, const int i) { }
26148 Note that when the template is first instantiated, with
26149 instantiate_template, the resulting DECL will have no name for the
26150 first parameter, and the wrong type for the second. So, when we go
26151 to instantiate the DECL, we regenerate it. */
26153 static void
26155 {
26156 /* The arguments used to instantiate DECL, from the most general
26157 template. */
26160 /* Make sure that we can see identifiers, and compute access correctly. */
26164 {
26165 tree specs;
26169 /* Use the source location of the definition. */
26177 /* Instantiate a dynamic exception-specification. noexcept will be
26178 handled below. */
26181 {
26187 specs);
26188 }
26190 /* Merge parameter declarations. */
26194 {
26201 }
26204 {
26205 /* If we're regenerating a specialization, the contracts will have
26206 been copied from the most general template. Replace those with
26207 the ones from the actual specialization. */
26210 {
26213 }
26216 }
26218 /* Merge additional specifiers from the CODE_PATTERN. */
26224 }
26226 {
26235 }
26236 else
26240 }
26242 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26243 substituted to get DECL. */
26245 tree
26247 {
26250 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26251 for the instantiation. This is not always the most general
26252 template. Consider, for example:
26254 template <class T>
26255 struct S { template <class U> void f();
26256 template <> void f<int>(); };
26258 and an instantiation of S<double>::f<int>. We want TD to be the
26259 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26261 more general template. */
26263 /* We must also deal with friend templates. Given:
26265 template <class T> struct S {
26266 template <class U> friend void f() {};
26267 };
26269 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26270 so far as the language is concerned, but that's still
26271 where we get the pattern for the instantiation from. On
26272 other hand, if the definition comes outside the class, say:
26274 template <class T> struct S {
26275 template <class U> friend void f();
26276 };
26277 template <class U> friend void f() {}
26279 we don't need to look any further. That's what the check for
26280 DECL_INITIAL is for. */
26284 {
26285 /* The present template, TD, should not be a definition. If it
26286 were a definition, we should be using it! Note that we
26287 cannot restructure the loop to just keep going until we find
26288 a template with a definition, since that might go too far if
26289 a specialization was declared, but not defined. */
26291 /* Fetch the more general template. */
26293 }
26296 }
26298 /* Returns true if we need to instantiate this template instance even if we
26299 know we aren't going to emit it. */
26301 bool
26303 {
26304 /* We always instantiate inline functions so that we can inline them. An
26305 explicit instantiation declaration prohibits implicit instantiation of
26306 non-inline functions. With high levels of optimization, we would
26307 normally inline non-inline functions -- but we're not allowed to do
26308 that for "extern template" functions. Therefore, we check
26309 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26313 /* And we need to instantiate static data members so that
26314 their initializers are available in integral constant
26315 expressions. */
26318 }
26320 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26321 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26322 error, true otherwise. */
26324 bool
26326 {
26330 /* Don't instantiate a noexcept-specification from template context. */
26340 {
26342 /* We're in start_preparsed_function, keep going. */
26349 }
26360 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26361 its FUNCTION_DECL for the rest of this function -- push_access_scope
26362 doesn't accept TEMPLATE_DECLs. */
26364 {
26367 }
26370 {
26375 }
26377 {
26381 {
26384 /* This might have failed because of an unparsed DMI, so
26385 let's try again later. */
26387 }
26389 {
26390 /* If hash_set::add returns true, the element was already there. */
26395 fn);
26397 }
26399 {
26407 {
26408 /* If needed, set current_class_ptr for the benefit of
26409 tsubst_copy/PARM_DECL. */
26414 }
26416 /* If this function is represented by a TEMPLATE_DECL, then
26417 the deferred noexcept-specification might still contain
26418 dependent types, even after substitution. And we need the
26419 dependency check functions to work in build_noexcept_spec. */
26423 /* Do deferred instantiation of the noexcept-specifier. */
26428 /* Build up the noexcept-specification. */
26438 }
26439 else
26444 }
26447 {
26448 /* This failed with a hard error, so let's go with false. */
26451 }
26458 }
26460 /* We're starting to process the function INST, an instantiation of PATTERN;
26461 add their parameters to local_specializations. */
26463 void
26465 {
26469 {
26473 }
26475 {
26477 {
26480 }
26481 else
26482 {
26483 /* Register the (value) argument pack as a specialization of
26484 TMPL_PARM, then move on. */
26487 }
26488 }
26490 }
26492 /* Instantiate the body of D using PATTERN with ARGS. We have
26493 already determined PATTERN is the correct template to use.
26494 NESTED_P is true if this is a nested function, in which case
26495 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26497 static void
26499 {
26504 {
26507 }
26508 else
26509 /* Only OMP reductions are nested. */
26516 bool push_to_top
26517 = !(current_function_decl
26523 else
26524 {
26529 }
26532 {
26533 /* The variable might be a lambda's extra scope, and that
26534 lambda's visibility depends on D's. */
26537 }
26539 /* Mark D as instantiated so that recursive calls to
26540 instantiate_decl do not try to instantiate it again. */
26544 /* Regenerate the declaration in case the template has been modified
26545 by a subsequent redeclaration. */
26548 /* We already set the file and line above. Reset them now in case
26549 they changed as a result of calling regenerate_decl_from_template. */
26553 {
26554 /* Clear out DECL_RTL; whatever was there before may not be right
26555 since we've reset the type of the declaration. */
26559 /* The initializer is placed in DECL_INITIAL by
26560 regenerate_decl_from_template so we don't need to
26561 push/pop_access_scope again here. Pull it out so that
26562 cp_finish_decl can process it. */
26568 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26569 initializer. That function will defer actual emission until
26570 we have a chance to determine linkage. */
26573 /* Enter the scope of D so that access-checking works correctly. */
26583 }
26587 {
26588 /* Set up the list of local specializations. */
26592 /* Set up context. */
26595 else
26596 {
26600 }
26602 /* Create substitution entries for the parameters. */
26605 /* Substitute into the body of the function. */
26609 else
26610 {
26614 /* Set the current input_location to the end of the function
26615 so that finish_function knows where we are. */
26616 input_location
26619 /* Remember if we saw an infinite loop in the template. */
26620 current_function_infinite_loop
26622 }
26624 /* Finish the function. */
26627 else
26628 {
26631 }
26635 }
26637 /* We're not deferring instantiation any more. */
26643 else
26648 }
26650 /* Produce the definition of D, a _DECL generated from a template. If
26651 DEFER_OK is true, then we don't have to actually do the
26652 instantiation now; we just have to do it sometime. Normally it is
26653 an error if this is an explicit instantiation but D is undefined.
26654 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26655 instantiated class template. */
26657 tree
26659 {
26661 tree gen_args;
26662 tree args;
26663 tree td;
26664 tree code_pattern;
26665 tree spec;
26666 tree gen_tmpl;
26674 /* This function should only be used to instantiate templates for
26675 functions and static member variables. */
26678 /* A concept is never instantiated. */
26684 /* We may have a pending instantiation of D itself. */
26687 /* Variables are never deferred; if instantiation is required, they
26688 are instantiated right away. That allows for better code in the
26689 case that an expression refers to the value of the variable --
26690 if the variable has a constant value the referring expression can
26691 take advantage of that fact. */
26695 /* Don't instantiate cloned functions. Instead, instantiate the
26696 functions they cloned. */
26705 /* D has already been instantiated or explicitly specialized, so
26706 there's nothing for us to do here.
26708 It might seem reasonable to check whether or not D is an explicit
26709 instantiation, and, if so, stop here. But when an explicit
26710 instantiation is deferred until the end of the compilation,
26711 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
26712 the instantiation. */
26715 /* Check to see whether we know that this template will be
26716 instantiated in some other file, as with "extern template"
26717 extension. */
26720 /* In general, we do not instantiate such templates. */
26727 /* We should already have the extra args. */
26731 /* And what's in the hash table should match D. */
26733 == d
26736 /* This needs to happen before any tsubsting. */
26742 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
26743 for the instantiation. */
26748 {
26749 /* Look up an explicit specialization, if any. */
26752 {
26755 }
26756 }
26760 /* We should never be trying to instantiate a member of a class
26761 template or partial specialization. */
26766 /* In the case of a friend template whose definition is provided
26767 outside the class, we may have too many arguments. Drop the
26768 ones we don't need. The same is true for specializations. */
26769 args = get_innermost_template_args
26773 {
26779 }
26780 else
26781 {
26785 else
26787 }
26789 /* We may be in the middle of deferred access check. Disable it now. */
26792 /* Unless an explicit instantiation directive has already determined
26793 the linkage of D, remember that a definition is available for
26794 this entity. */
26804 /* If D is a member of an explicitly instantiated class template,
26805 and no definition is available, treat it like an implicit
26806 instantiation. */
26809 {
26810 /* Leave linkage flags alone on instantiations with anonymous
26811 visibility. */
26813 {
26816 }
26818 }
26820 /* Defer all other templates, unless we have been explicitly
26821 forbidden from doing so. */
26823 template. */
26824 ! pattern_defined
26825 /* If it's OK to postpone instantiation, do so. */
26826 || defer_ok
26827 /* If this is a static data member that will be defined
26828 elsewhere, we don't want to instantiate the entire data
26829 member, but we do want to instantiate the initializer so that
26830 we can substitute that elsewhere. */
26832 /* Handle here a deleted function too, avoid generating
26833 its body (c++/61080). */
26835 {
26836 /* The definition of the static data member is now required so
26837 we must substitute the initializer. */
26841 {
26842 tree ns;
26843 tree init;
26852 args,
26854 /* If instantiating the initializer involved instantiating this
26855 again, don't call cp_finish_decl twice. */
26857 {
26858 /* Make sure the initializer is still constant, in case of
26859 circular dependency (template/instantiate6.C). */
26860 const_init
26864 }
26868 }
26870 /* We restore the source position here because it's used by
26871 add_pending_template. */
26877 /* [temp.explicit]
26879 The definition of a non-exported function template, a
26880 non-exported member function template, or a non-exported
26881 member function or static data member of a class template
26882 shall be present in every translation unit in which it is
26883 explicitly instantiated. */
26887 /* If we're in unevaluated context, we just wanted to get the
26888 constant value; this isn't an odr use, so don't queue
26889 a full instantiation. */
26891 /* ??? Historically, we have instantiated inline functions, even
26892 when marked as "extern template". */
26895 }
26896 else
26897 {
26902 }
26911 }
26913 /* Run through the list of templates that we wish we could
26914 instantiate, and instantiate any we can. RETRIES is the
26915 number of times we retry pending template instantiation. */
26917 void
26919 {
26923 /* Instantiating templates may trigger vtable generation. This in turn
26924 may require further template instantiations. We place a limit here
26925 to avoid infinite loop. */
26927 {
26931 "template instantiation depth exceeds maximum of %d"
26932 " instantiating %q+D, possibly from virtual table generation"
26936 /* Pretend that we defined it. */
26939 }
26941 do
26942 {
26947 {
26952 {
26954 {
26969 }
26972 }
26973 else
26974 {
26977 {
26978 instantiation
26984 }
26988 }
26991 {
26992 /* If INSTANTIATION has been instantiated, then we don't
26993 need to consider it again in the future. */
26998 }
26999 else
27000 {
27003 }
27006 }
27008 }
27012 }
27014 /* Substitute ARGVEC into T, which is a list of initializers for
27015 either base class or a non-static data member. The TREE_PURPOSEs
27016 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27017 instantiate_decl. */
27019 static tree
27021 {
27026 {
27027 tree decl;
27028 tree init;
27034 {
27035 tree expr;
27036 tree arg;
27038 /* Expand the base class expansion type into separate base
27039 classes. */
27041 tf_warning_or_error,
27042 NULL_TREE);
27046 /* We'll be building separate TREE_LISTs of arguments for
27047 each base. */
27053 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27054 expand each argument in the TREE_VALUE of t. */
27061 /* VOID_TYPE_NODE is used to indicate
27062 value-initialization. */
27063 {
27066 }
27067 else
27068 {
27069 /* Substitute parameter packs into each argument in the
27070 TREE_LIST. */
27073 {
27074 tree expanded_exprs;
27076 /* Expand the argument. */
27077 tree value;
27080 else
27081 {
27084 }
27085 expanded_exprs
27087 tf_warning_or_error,
27088 NULL_TREE);
27092 /* Prepend each of the expanded expressions to the
27093 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27101 else
27106 }
27109 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27110 since we built them backwards. */
27112 {
27115 }
27116 }
27117 }
27120 {
27122 {
27126 }
27127 else
27128 {
27129 tree tmp;
27143 /* If we had an initializer but it instantiated to nothing,
27144 value-initialize the object. This will only occur when
27145 the initializer was a pack expansion where the parameter
27146 packs used in that expansion were of length zero. */
27149 }
27153 {
27155 decl);
27157 }
27158 /* Look for a target constructor. */
27162 {
27165 {
27169 }
27171 }
27174 {
27176 /* Carry over the dummy TREE_TYPE node containing the source
27177 location. */
27181 }
27182 }
27183 }
27185 }
27187 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27188 is the instantiation (which should have been created with
27189 start_enum) and ARGS are the template arguments to use. */
27191 static void
27193 {
27194 tree e;
27200 {
27201 tree value;
27204 /* Note that in a template enum, the TREE_VALUE is the
27205 CONST_DECL, not the corresponding INTEGER_CST. */
27209 /* Give this enumeration constant the correct access. */
27212 /* Actually build the enumerator itself. Here we're assuming that
27213 enumerators can't have dependent attributes. */
27217 /* Attribute deprecated without an argument isn't sticky: it'll
27218 melt into a tree flag, so we need to propagate the flag here,
27219 since we just created a new enumerator. */
27222 }
27234 }
27236 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27237 its type -- but without substituting the innermost set of template
27238 arguments. So, innermost set of template parameters will appear in
27239 the type. */
27241 tree
27243 {
27244 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27246 }
27248 /* Return truthvalue if we're processing a template different from
27249 the last one involved in diagnostics. */
27250 bool
27252 {
27254 }
27256 /* Remember current template involved in diagnostics. */
27257 void
27259 {
27261 }
27265 {
27267 }
27269 /* Return TRUE if current_function_decl is being instantiated, false
27270 otherwise. */
27272 bool
27274 {
27278 }
27280 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27281 type. Return false for ok, true for disallowed. Issue error and
27282 inform messages under control of COMPLAIN. */
27284 static bool
27286 {
27297 {
27299 {
27304 }
27306 }
27311 /* Fall through; before C++11 alias templates, a bound ttp
27314 /* Any other wildcard type not already handled above is allowed. */
27321 {
27329 {
27330 auto_diagnostic_group d;
27334 }
27336 }
27338 {
27343 }
27346 {
27349 else
27351 type);
27352 }
27354 }
27356 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27358 static bool
27360 {
27363 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27364 affect overload resolution and treating it as dependent breaks
27365 things. Same for an unparsed noexcept expression. */
27372 }
27374 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27375 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27377 static bool
27379 {
27380 tree scope;
27382 /* [temp.dep.type]
27384 A type is dependent if it is:
27386 -- a template parameter. Template template parameters are types
27387 for us (since TYPE_P holds true for them) so we handle
27388 them here. */
27392 /* -- a qualified-id with a nested-name-specifier which contains a
27393 class-name that names a dependent type or whose unqualified-id
27394 names a dependent type. */
27398 /* An alias template specialization can be dependent even if the
27399 resulting type is not. */
27403 /* -- a cv-qualified type where the cv-unqualified type is
27404 dependent.
27405 No code is necessary for this bullet; the code below handles
27406 cv-qualified types, and we don't want to strip aliases with
27407 TYPE_MAIN_VARIANT because of DR 1558. */
27408 /* -- a compound type constructed from any dependent type. */
27416 {
27417 tree arg_type;
27422 arg_type;
27428 /* A value-dependent noexcept-specifier makes the type dependent. */
27431 }
27432 /* -- an array type constructed from any dependent type or whose
27433 size is specified by a constant expression that is
27434 value-dependent.
27436 We checked for type- and value-dependence of the bounds in
27437 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27439 {
27444 }
27446 /* -- a template-id in which either the template name is a template
27447 parameter ... */
27450 /* ... or any of the template arguments is a dependent type or
27451 an expression that is type-dependent or value-dependent. */
27453 && (any_dependent_template_arguments_p
27457 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27458 dependent; if the argument of the `typeof' expression is not
27459 type-dependent, then it should already been have resolved. */
27465 /* A template argument pack is dependent if any of its packed
27466 arguments are. */
27468 {
27473 }
27475 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27476 be template parameters. */
27486 /* The standard does not specifically mention types that are local
27487 to template functions or local classes, but they should be
27488 considered dependent too. For example:
27490 template <int I> void f() {
27491 enum E { a = I };
27492 S<sizeof (E)> s;
27493 }
27495 The size of `E' cannot be known until the value of `I' has been
27496 determined. Therefore, `E' must be considered dependent. */
27500 /* Don't use type_dependent_expression_p here, as it can lead
27501 to infinite recursion trying to determine whether a lambda
27502 nested in a lambda is dependent (c++/47687). */
27506 && (any_dependent_template_arguments_p
27510 /* Other types are non-dependent. */
27512 }
27514 /* Returns TRUE if TYPE is dependent, in the sense of
27515 [temp.dep.type]. Note that a NULL type is considered dependent. */
27517 bool
27519 {
27520 /* If there are no template parameters in scope, then there can't be
27521 any dependent types. */
27523 {
27524 /* If we are not processing a template, then nobody should be
27525 providing us with a dependent type. */
27529 }
27531 /* If the type is NULL, we have not computed a type for the entity
27532 in question; in that case, the type is dependent. */
27536 /* Erroneous types can be considered non-dependent. */
27540 /* If we have not already computed the appropriate value for TYPE,
27541 do so now. */
27543 {
27546 }
27549 }
27551 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27552 lookup. In other words, a dependent type that is not the current
27553 instantiation. */
27555 bool
27557 {
27560 }
27562 /* True if we might find more declarations in SCOPE during instantiation than
27563 we can when parsing the template. */
27565 bool
27567 {
27569 }
27571 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27572 an unknown base of 'this' (and is therefore instantiation-dependent). */
27574 static bool
27576 {
27593 }
27595 /* T is a SCOPE_REF; return whether we need to consider it
27596 instantiation-dependent so that we can check access at instantiation
27597 time even though we know which member it resolves to. */
27599 static bool
27601 {
27609 else
27611 }
27613 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27614 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27615 expression. */
27617 /* Note that this predicate is not appropriate for general expressions;
27618 only constant expressions (that satisfy potential_constant_expression)
27619 can be tested for value dependence. */
27621 bool
27623 {
27627 /* A type-dependent expression is also value-dependent. */
27632 {
27634 /* A dependent member function of the current instantiation. */
27638 /* A dependent member function of the current instantiation. */
27645 /* A name that has not been looked up -- must be dependent. */
27649 /* A non-type template parm. */
27653 /* A non-type template parm. */
27659 /* A constant with literal type and is initialized
27660 with an expression that is value-dependent. */
27662 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27666 {
27669 /* __PRETTY_FUNCTION__ inside a template function is dependent
27670 on the name of the function. */
27672 /* It might be used in a template, but not a template
27673 function, in which case its DECL_VALUE_EXPR will be
27674 "top level". */
27677 }
27686 /* These expressions are value-dependent if the type to which
27687 the cast occurs is dependent or the expression being casted
27688 is value-dependent. */
27689 {
27695 /* A functional cast has a list of operands. */
27698 {
27699 /* If there are no operands, it must be an expression such
27700 as "int()". This should not happen for aggregate types
27701 because it would form non-constant expressions. */
27706 }
27716 }
27721 /* FALLTHRU */
27724 /* A `sizeof' expression is value-dependent if the operand is
27725 type-dependent or is a pack expansion. */
27734 /* An 'encode' expression is value-dependent if the operand is
27735 type-dependent. */
27744 /* All instantiation-dependent expressions should also be considered
27745 value-dependent. */
27753 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
27754 is value-dependent. */
27761 {
27778 }
27789 {
27793 }
27796 /* Treat all requires-expressions as value-dependent so
27797 we don't try to fold them. */
27804 {
27811 {
27813 /* In a call to a constexpr member function, look through the
27814 implicit ADDR_EXPR on the object argument so that it doesn't
27815 cause the call to be considered value-dependent. We also
27816 look through it in potential_constant_expression. */
27823 }
27825 }
27832 {
27834 tree val;
27841 }
27844 /* Treat a GNU statement expression as dependent to avoid crashing
27845 under instantiate_non_dependent_expr; it can't be constant. */
27850 /* The second operand is a type, which type_dependent_expression_p
27851 (and therefore value_dependent_expression_p) doesn't want to see. */
27857 /* A constant expression is value-dependent if any subexpression is
27858 value-dependent. */
27860 {
27867 {
27871 {
27874 /* In some cases, some of the operands may be missing.
27875 (For example, in the case of PREDECREMENT_EXPR, the
27876 amount to increment by may be missing.) That doesn't
27877 make the expression dependent. */
27880 }
27881 }
27885 }
27887 }
27889 /* The expression is not value-dependent. */
27891 }
27893 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
27894 [temp.dep.expr]. Note that an expression with no type is
27895 considered dependent. Other parts of the compiler arrange for an
27896 expression with type-dependent subexpressions to have no type, so
27897 this function doesn't have to be fully recursive. */
27899 bool
27901 {
27912 /* An unresolved name is always dependent. */
27918 /* A lambda-expression in template context is dependent. dependent_type_p is
27919 true for a lambda in the scope of a class or function template, but that
27920 doesn't cover all template contexts, like a default template argument. */
27924 /* A fold expression is type-dependent. */
27931 /* Some expression forms are never type-dependent. */
27944 /* The types of these expressions depends only on the type to which
27945 the cast occurs. */
27954 /* The types of these expressions depends only on the type created
27955 by the expression. */
27958 {
27959 /* For NEW_EXPR tree nodes created inside a template, either
27960 the object type itself or a TREE_LIST may appear as the
27961 operand 1. */
27964 /* This is an array type. We need to check array dimensions
27965 as well. */
27967 || value_dependent_expression_p
27969 /* Array type whose dimension has to be deduced. */
27973 else
27975 }
27978 {
27982 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
27983 contains an identifier associated by name lookup with one or more
27984 declarations declared with a dependent type, or...a
27985 nested-name-specifier or qualified-id that names a member of an
27986 unknown specialization. */
27989 }
27999 {
28004 }
28006 /* A static data member of the current instantiation with incomplete
28007 array type is type-dependent, as the definition and specializations
28008 can have different bounds. */
28015 /* An array of unknown bound depending on a variadic parameter, eg:
28017 template<typename... Args>
28018 void foo (Args... args)
28019 {
28020 int arr[] = { args... };
28021 }
28023 template<int... vals>
28024 void bar ()
28025 {
28026 int arr[] = { vals... };
28027 }
28029 If the array has no length and has an initializer, it must be that
28030 we couldn't determine its length in cp_complete_array_type because
28031 it is dependent. */
28039 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28041 {
28046 }
28048 /* A function or variable template-id is type-dependent if it has any
28049 dependent template arguments. */
28053 {
28054 /* Consider the innermost template arguments, since those are the ones
28055 that come from the template-id; the template arguments for the
28056 enclosing class do not make it type-dependent unless they are used in
28057 the type of the decl. */
28059 && (any_dependent_template_arguments_p
28062 }
28064 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28065 type-dependent. Checking this is important for functions with auto return
28066 type, which looks like a dependent type. */
28075 {
28079 }
28081 /* Otherwise, its constraints could still depend on outer template parameters
28082 from its (dependent) scope. */
28084 /* As an optimization, check this cheaper sufficient condition first.
28085 (At this point we've established that we're looking at a member of
28086 a dependent class, so it makes sense to start treating say undeduced
28087 auto as dependent.) */
28092 /* Always dependent, on the number of arguments if nothing else. */
28097 {
28102 {
28108 }
28109 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28113 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28119 {
28124 }
28127 {
28134 }
28143 }
28145 /* The type of a non-type template parm declared with a placeholder type
28146 depends on the corresponding template argument, even though
28147 placeholders are not normally considered dependent. */
28154 /* Dependent type attributes might not have made it from the decl to
28155 the type yet. */
28161 }
28163 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28164 type-dependent if the expression refers to a member of the current
28165 instantiation and the type of the referenced member is dependent, or the
28166 class member access expression refers to a member of an unknown
28167 specialization.
28169 This function returns true if the OBJECT in such a class member access
28170 expression is of an unknown specialization. */
28172 bool
28174 {
28175 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28176 dependent. */
28181 }
28183 /* walk_tree callback function for instantiation_dependent_expression_p,
28184 below. Returns non-zero if a dependent subexpression is found. */
28186 static tree
28189 {
28191 {
28192 /* We don't have to worry about decltype currently because decltype
28193 of an instantiation-dependent expr is a dependent type. This
28194 might change depending on the resolution of DR 1172. */
28197 }
28200 {
28201 /* Don't treat an argument list as dependent just because it has no
28202 TREE_TYPE. */
28213 /* We'll check value-dependence separately. */
28216 /* Handle expressions with type operands. */
28221 {
28226 {
28229 else
28230 {
28233 }
28234 }
28236 }
28240 /* In a template, finish_class_member_access_expr creates a
28241 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28242 type-dependent, so that we can check access control at
28243 instantiation time (PR 42277). See also Core issue 1273. */
28250 else
28253 /* Treat statement-expressions as dependent. */
28257 /* Treat requires-expressions as dependent. */
28268 /* Before C++17, a noexcept-specifier isn't part of the function type
28269 so it doesn't affect type dependence, but we still want to consider it
28270 for instantiation dependence. */
28279 }
28283 else
28285 }
28287 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28288 sense defined by the ABI:
28290 "An expression is instantiation-dependent if it is type-dependent
28291 or value-dependent, or it has a subexpression that is type-dependent
28292 or value-dependent."
28294 Except don't actually check value-dependence for unevaluated expressions,
28295 because in sizeof(i) we don't care about the value of i. Checking
28296 type-dependence will in turn check value-dependence of array bounds/template
28297 arguments as needed. */
28299 bool
28301 {
28302 tree result;
28313 }
28315 /* As above, but also check value-dependence of the expression as a whole. */
28317 bool
28319 {
28321 || (processing_template_decl
28324 }
28326 /* Like type_dependent_expression_p, but it also works while not processing
28327 a template definition, i.e. during substitution or mangling. */
28329 bool
28331 {
28337 }
28339 /* Returns TRUE if ARGS contains a type-dependent expression. */
28341 bool
28343 {
28345 tree arg;
28348 {
28351 }
28353 }
28355 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28356 expressions) contains any type-dependent expressions. */
28358 bool
28360 {
28366 }
28368 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28369 expressions) contains any value-dependent expressions. */
28371 bool
28373 {
28379 }
28381 /* Returns TRUE if the ARG (a template argument) is dependent. */
28383 bool
28385 {
28389 /* Assume a template argument that was wrongly written by the user
28390 is dependent. This is consistent with what
28391 any_dependent_template_arguments_p [that calls this function]
28392 does. */
28402 {
28405 /* A member template of a dependent class is not necessarily
28406 type-dependent, but it is a dependent template argument because it
28407 will be a member of an unknown specialization to that template. */
28410 }
28412 {
28418 }
28421 else
28423 }
28425 /* Identify any expressions that use function parms. */
28427 static tree
28429 {
28432 {
28435 }
28437 }
28439 /* Returns true if a type specialization formed using the template
28440 arguments ARGS needs to use structural equality. */
28442 bool
28444 {
28454 {
28457 {
28463 {
28464 /* Look inside the argument pack. */
28467 }
28470 {
28479 /* An any_targ_node argument (added by add_defaults_to_ttp)
28480 makes the corresponding specialization not canonicalizable,
28481 since template_args_equal always return true for it. We
28482 may see this when called from bind_template_template_parm. */
28484 /* Checking current_function_decl because this structural
28485 comparison is only necessary for redeclaration. */
28488 && (cp_walk_tree_without_duplicates
28490 /* The identity of a class template specialization that uses
28491 a function parameter depends on the identity of the function.
28492 And if this specialization appeared in the trailing return
28493 type thereof, we don't know the identity of the function
28494 (e.g. if it's a redeclaration or a new function) until we
28495 form its signature and go through duplicate_decls. Thus
28496 it's unsafe to decide on a canonical type now (which depends
28497 on the DECL_CONTEXT of the function parameter, which can get
28498 mutated after the fact by duplicate_decls), so just require
28499 structural equality in this case (PR52830). */
28501 }
28502 }
28503 }
28506 }
28508 /* Returns true if ARGS (a collection of template arguments) contains
28509 any dependent arguments. */
28511 bool
28513 {
28523 {
28528 }
28531 }
28533 /* Returns true if ARGS contains any errors. */
28535 bool
28537 {
28545 {
28548 else
28550 }
28556 {
28561 }
28564 }
28566 /* Returns TRUE if the template TMPL is type-dependent. */
28568 bool
28570 {
28572 {
28577 }
28579 /* Template template parameters are dependent. */
28583 /* So are names that have not been looked up. */
28587 }
28589 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28591 bool
28593 {
28596 }
28598 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28599 are dependent. */
28601 bool
28603 {
28610 {
28635 {
28639 }
28643 {
28647 {
28653 /* If this loop has a class iterator with != comparison
28654 with increment other than i++/++i/i--/--i, make sure the
28655 increment is constant. */
28658 {
28661 else
28665 }
28666 }
28667 }
28668 }
28671 }
28673 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28674 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28675 no such TYPE can be found. Note that this function peers inside
28676 uninstantiated templates and therefore should be used only in
28677 extremely limited situations. ONLY_CURRENT_P restricts this
28678 peering to the currently open classes hierarchy (which is required
28679 when comparing types). */
28681 tree
28683 {
28684 tree scope;
28685 tree name;
28686 tree decl;
28688 tree pushed_scope;
28689 tree result;
28694 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28697 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28698 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
28699 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
28700 representing the typedef. In that case TYPE_IDENTIFIER (type) is
28701 not the non-qualified identifier of the TYPENAME_TYPE anymore.
28702 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
28703 the TYPENAME_TYPE instead, we avoid messing up with a possible
28704 typedef variant case. */
28707 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
28708 it first before we can figure out what NAME refers to. */
28710 {
28712 /* Given a class template A with a dependent base with nested type C,
28713 typedef typename A::C::C C will land us here, as trying to resolve
28714 the initial A::C leads to the local C typedef, which leads back to
28715 A::C::C. So we break the recursion now. */
28717 else
28719 }
28720 /* If we don't know what SCOPE refers to, then we cannot resolve the
28721 TYPENAME_TYPE. */
28724 /* If this is a typedef, we don't want to look inside (c++/11987). */
28727 /* If SCOPE isn't the template itself, it will not have a valid
28728 TYPE_FIELDS list. */
28730 /* scope is either the template itself or a compatible instantiation
28731 like X<T>, so look up the name in the original template. */
28733 /* If scope has no fields, it can't be a current instantiation. Check this
28734 before currently_open_class to avoid infinite recursion (71515). */
28737 /* If the SCOPE is not the current instantiation, there's no reason
28738 to look inside it. */
28741 /* Enter the SCOPE so that name lookup will be resolved as if we
28742 were in the class definition. In particular, SCOPE will no
28743 longer be considered a dependent type. */
28745 /* Look up the declaration. */
28747 tf_warning_or_error);
28751 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
28752 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
28758 {
28762 }
28765 {
28766 /* Obtain the template and the arguments. */
28769 {
28770 /* We get here with a plain identifier because a previous tentative
28771 parse of the nested-name-specifier as part of a ptr-operator saw
28772 ::template X<A>. The use of ::template is necessary in a
28773 ptr-operator, but wrong in a declarator-id.
28775 [temp.names]: In a qualified-id of a declarator-id, the keyword
28776 template shall not appear at the top level. */
28780 }
28782 /* Instantiate the template. */
28788 }
28790 /* Leave the SCOPE. */
28794 /* If we failed to resolve it, return the original typename. */
28798 /* If lookup found a typename type, resolve that too. */
28800 {
28801 /* Ill-formed programs can cause infinite recursion here, so we
28802 must catch that. */
28806 }
28808 /* Qualify the resulting type. */
28814 }
28816 /* EXPR is an expression which is not type-dependent. Return a proxy
28817 for EXPR that can be used to compute the types of larger
28818 expressions containing EXPR. */
28820 tree
28822 {
28824 tree inner_expr;
28826 /* When checking, try to get a constant value for all non-dependent
28827 expressions in order to expose bugs in *_dependent_expression_p
28828 and constexpr. This can affect code generation, see PR70704, so
28829 only do this for -fchecking=2. */
28832 /* Don't do this during nsdmi parsing as it can lead to
28833 unexpected recursive instantiations. */
28835 /* Don't do this during concept processing either and for
28836 the same reason. */
28842 /* Preserve OVERLOADs; the functions must be available to resolve
28843 types. */
28854 /* There is no need to return a proxy for a variable, parameter
28855 or enumerator. */
28859 /* Preserve string constants; conversions from string constants to
28860 "char *" are allowed, even though normally a "const char *"
28861 cannot be used to initialize a "char *". */
28864 /* Preserve void and arithmetic constants, as an optimization -- there is no
28865 reason to create a new node. */
28870 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
28871 There is at least one place where we want to know that a
28872 particular expression is a throw-expression: when checking a ?:
28873 expression, there are special rules if the second or third
28874 argument is a throw-expression. */
28878 /* Don't wrap an initializer list, we need to be able to look inside. */
28882 /* Don't wrap a dummy object, we need to be able to test for it. */
28900 /* If the type is unknown, it can't really be non-dependent */
28903 /* Otherwise, build a NON_DEPENDENT_EXPR. */
28906 }
28908 /* ARGS is a vector of expressions as arguments to a function call.
28909 Replace the arguments with equivalent non-dependent expressions.
28910 This modifies ARGS in place. */
28912 void
28914 {
28916 tree arg;
28919 {
28923 }
28924 }
28926 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
28927 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
28928 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
28930 static tree
28932 {
28948 }
28950 tree
28952 {
28954 }
28956 tree
28958 {
28960 }
28962 /* Return a C++17 deduction placeholder for class template TMPL.
28963 There are represented as an 'auto' with the special level 0 and
28964 CLASS_PLACEHOLDER_TEMPLATE set. */
28966 tree
28968 {
28971 /* Our canonical type depends on the placeholder. */
28974 }
28976 /* True iff T is a C++17 class template deduction placeholder. */
28978 bool
28980 {
28982 }
28984 /* Make a "constrained auto" type-specifier. This is an auto or
28985 decltype(auto) type with constraints that must be associated after
28986 deduction. The constraint is formed from the given concept CON
28987 and its optional sequence of template arguments ARGS.
28989 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
28991 static tree
28993 {
28994 /* Build the constraint. */
29006 /* Our canonical type depends on the constraint. */
29009 /* Attach the constraint to the type declaration. */
29011 }
29013 /* Make a "constrained auto" type-specifier. */
29015 tree
29017 {
29020 }
29022 /* Make a "constrained decltype(auto)" type-specifier. */
29024 tree
29026 {
29029 }
29031 /* Returns true if the placeholder type constraint T has any dependent
29032 (explicit) template arguments. */
29034 static bool
29036 {
29041 {
29044 }
29051 }
29053 /* Build and return a concept definition. Like other templates, the
29054 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29055 the TEMPLATE_DECL. */
29057 tree
29059 {
29065 /* A concept-definition shall not have associated constraints. */
29067 {
29070 }
29072 /* A concept-definition shall appear in namespace scope. Templates
29073 aren't allowed in block scope, so we only need to check for class
29074 scope. */
29076 {
29079 }
29082 {
29085 }
29087 /* Initially build the concept declaration; its type is bool. */
29097 /* Push the enclosing template. */
29099 }
29101 /* Given type ARG, return std::initializer_list<ARG>. */
29103 static tree
29105 {
29110 {
29114 "deducing from brace-enclosed initializer list"
29118 }
29124 }
29126 /* Replace auto in TYPE with std::initializer_list<auto>. */
29128 static tree
29130 {
29137 }
29139 /* Hash traits for hashing possibly constrained 'auto'
29140 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29143 {
29146 };
29148 /* Hash the 'auto' T. */
29150 inline hashval_t
29152 {
29154 /* Matching constrained-type-specifiers denote the same template
29155 parameter, so hash the constraint. */
29157 else
29158 /* But unconstrained autos are all separate, so just hash the pointer. */
29160 }
29162 /* Compare two 'auto's. */
29166 {
29173 /* Two unconstrained autos are distinct. */
29178 }
29180 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29181 constrained) auto, add it to the vector. */
29183 static int
29185 {
29188 {
29189 /* All the autos were built with index 0; fix that up now. */
29193 /* If this is a repeated constrained-type-specifier, use the index we
29194 chose before. */
29196 else
29197 {
29198 /* Otherwise this is new, so use the current count. */
29201 }
29203 }
29205 /* Always keep walking. */
29207 }
29209 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29210 says they can appear anywhere in the type. */
29212 static tree
29214 {
29222 {
29226 }
29229 }
29231 /* The stem for deduction guide names. */
29234 /* Return the name for a deduction guide for class template TMPL. */
29236 tree
29238 {
29249 }
29251 /* True if NAME is the name of a deduction guide. */
29253 bool
29255 {
29259 }
29261 /* True if FN is a deduction guide. */
29263 bool
29265 {
29270 }
29272 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29274 bool
29276 {
29283 }
29285 /* True if FN is a guide generated from a constructor template. */
29287 bool
29289 {
29297 }
29299 /* True if FN is an aggregate initialization guide or the copy deduction
29300 guide. */
29302 bool
29304 {
29308 /* Explicitly declared. */
29311 /* Derived from a constructor. */
29314 }
29316 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29317 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29318 template parameter types. Note that the handling of template template
29319 parameters relies on current_template_parms being set appropriately for the
29320 new template. */
29322 static tree
29325 {
29331 tree newtype;
29334 {
29338 }
29339 else
29340 {
29343 {
29344 // Substitute once to fix references to other template parameters.
29347 // Now substitute again to reduce the level of the auto.
29350 }
29351 else
29354 }
29356 tree newdecl
29361 tree newidx;
29364 {
29373 {
29378 // First create a copy (ttargs) of tsubst_args with an
29379 // additional level for the template template parameter's own
29380 // template parameters (ttparms).
29381 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29389 // Substitute ttargs into ttparms to fix references to
29390 // other template parameters.
29393 // Now substitute again with args based on tparms, to reduce
29394 // the level of the ttparms.
29397 complain);
29398 // Finally, tack the adjusted parms onto tparms.
29401 // As with all template template parms, the parameter list captured
29402 // by this template template parm that corresponds to its own level
29403 // should be empty. This avoids infinite recursion when structurally
29404 // comparing two such rewritten template template parms (PR102479).
29409 // All done.
29411 }
29415 else
29417 }
29418 else
29419 {
29421 tree newconst
29433 }
29436 }
29438 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29439 template parameter. */
29441 static tree
29444 {
29459 }
29461 /* Returns a C++17 class deduction guide template based on the constructor
29462 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29463 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29464 aggregate initialization guide. OUTER_ARGS are the template arguments
29465 for the enclosing scope of the class. */
29467 static tree
29469 {
29473 location_t loc;
29477 {
29481 }
29484 {
29486 {
29490 else
29492 }
29495 else
29505 }
29506 else
29507 {
29513 fn_tmpl
29521 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29522 fully specialized args for the enclosing class. Strip those off, as
29523 the deduction guide won't have those template parameters. */
29526 /* Discard the 'this' parameter. */
29534 {
29537 /* For a member template constructor, we need to flatten the two
29538 template parameter lists into one, and then adjust the function
29539 signature accordingly. This gets...complicated. */
29542 /* For a member template we should have two levels of parms/args, one
29543 for the class and one for the constructor. We stripped
29544 specialized args for further enclosing classes above. */
29548 /* Template args for translating references to the two-level template
29549 parameters into references to the one-level template parameters we
29550 are creating. */
29555 /* Template parms for the constructor template. */
29558 /* Template parms for the class template. */
29562 /* Template parms for the deduction guide start as a copy of the
29563 template parms for the class. We set current_template_parms for
29564 lookup_template_class_1. */
29570 /* Now we need to rewrite the constructor parms to append them to the
29571 class parms. */
29573 {
29577 tree newelt
29583 }
29585 /* Now we have a final set of template parms to substitute into the
29586 function signature. */
29593 {
29595 /* FIXME: We'd like to avoid substituting outer template
29596 arguments into the constraint ahead of time, but the
29597 construction of tsubst_args assumes that outer arguments
29598 are already substituted in. */
29601 }
29603 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29604 cp_unevaluated_operand. */
29605 cp_evaluated ev;
29608 }
29609 else
29610 {
29611 /* Substitute in the same arguments to rewrite class members into
29612 references to members of an unknown specialization. */
29613 cp_evaluated ev;
29617 {
29619 /* FIXME: As above. */
29622 }
29623 }
29628 }
29631 {
29632 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29636 }
29640 FUNCTION_DECL,
29655 }
29657 /* Add to LIST the member types for the reshaped initializer CTOR. */
29659 static tree
29661 {
29665 {
29669 {
29675 }
29679 /* Give the trailing pack expansion parameter a default argument to
29680 match aggregate initialization behavior, even if we deduce the
29681 length of the pack separately to more than we have initializers. */
29683 /* if ei is of array type and xi is a braced-init-list or string literal,
29684 Ti is an rvalue reference to the declared type of ei */
29689 {
29691 ftype = cp_build_qualified_type
29693 ftype = (cp_build_reference_type
29695 }
29697 }
29700 }
29702 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
29704 static bool
29706 {
29712 tree tparms = (INNERMOST_TEMPLATE_PARMS
29719 }
29723 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
29724 INIT. */
29726 static tree
29728 {
29736 {
29742 }
29744 /* We might be creating a guide for a class member template, e.g.,
29746 template<typename U> struct A {
29747 template<typename T> struct B { T t; };
29748 };
29750 At this point, A will have been instantiated. Below, we need to
29751 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
29752 const bool member_template_p
29756 tree template_type = (member_template_p
29762 /* No aggregate candidate for copy-initialization. */
29764 {
29768 }
29770 /* If we encounter a problem, we just won't add the candidate. */
29775 {
29780 /* If we're creating a deduction guide for a member class template,
29781 we've used the original template pattern type for the reshape_init
29782 above; this is done because we want PARMS to be a template parameter
29783 type, something that can be deduced when used as a function template
29784 parameter. At this point the outer class template has already been
29785 partially instantiated (we deferred the deduction until the enclosing
29786 scope is non-dependent). Therefore we have to partially instantiate
29787 PARMS, so that its template level is properly reduced and we don't get
29788 mismatches when deducing types using the guide with PARMS. */
29790 {
29794 }
29795 }
29797 {
29800 len;
29802 {
29808 }
29809 }
29810 else
29811 /* Aggregate initialization doesn't apply to an initializer expression. */
29815 {
29821 }
29824 }
29826 /* UGUIDES are the deduction guides for the underlying template of alias
29827 template TMPL; adjust them to be deduction guides for TMPL. */
29829 static tree
29831 {
29832 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
29833 class type (9.2.8.2) where the template-name names an alias template A,
29834 the defining-type-id of A must be of the form
29836 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29838 as specified in 9.2.8.2. The guides of A are the set of functions or
29839 function templates formed as follows. For each function or function
29840 template f in the guides of the template named by the simple-template-id
29841 of the defining-type-id, the template arguments of the return type of f
29842 are deduced from the defining-type-id of A according to the process in
29843 13.10.2.5 with the exception that deduction does not fail if not all
29844 template arguments are deduced. Let g denote the result of substituting
29845 these deductions into f. If substitution succeeds, form a function or
29846 function template f' with the following properties and add it to the set
29847 of guides of A:
29849 * The function type of f' is the function type of g.
29851 * If f is a function template, f' is a function template whose template
29852 parameter list consists of all the template parameters of A (including
29853 their default template arguments) that appear in the above deductions or
29854 (recursively) in their default template arguments, followed by the
29855 template parameters of f that were not deduced (including their default
29856 template arguments), otherwise f' is not a function template.
29858 * The associated constraints (13.5.2) are the conjunction of the
29859 associated constraints of g and a constraint that is satisfied if and only
29860 if the arguments of A are deducible (see below) from the return type.
29862 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
29863 be so as well.
29865 * If f was generated from a deduction-guide (12.4.1.8), then f' is
29866 considered to be so as well.
29868 * The explicit-specifier of f' is the explicit-specifier of g (if
29869 any). */
29871 /* This implementation differs from the above in two significant ways:
29873 1) We include all template parameters of A, not just some.
29874 2) The added constraint is same_type instead of deducible.
29876 I believe that while it's probably possible to construct a testcase that
29877 behaves differently with this simplification, it should have the same
29878 effect for real uses. Including all template parameters means that we
29879 deduce all parameters of A when resolving the call, so when we're in the
29880 constraint we don't need to deduce them again, we can just check whether
29881 the deduction produced the desired result. */
29890 {
29897 {
29901 /* Deduce template arguments for f from the type-id of A. */
29909 /* The number of parms for f' is the number of parms for A plus
29910 non-deduced parms of f. */
29918 /* Set current_template_parms as in build_deduction_guide. */
29923 /* First copy over the parms of A. */
29926 /* Now rewrite the non-deduced parms of f. */
29929 {
29937 }
29940 /* Substitute the deduced arguments plus the rewritten template
29941 parameters into f to get g. This covers the type, copyness,
29942 guideness, and explicit-specifier. */
29943 tree g;
29944 {
29945 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
29946 if cp_unevaluated_operand. */
29947 cp_evaluated ev;
29949 }
29960 /* Substitute the associated constraints. */
29967 /* Add a constraint that the return type matches the instantiation of
29968 A with the same template arguments. */
29971 /* FIXME this should mean they don't compare as equivalent. */
29973 {
29976 }
29979 {
29982 }
29983 }
29984 else
29985 {
29986 /* For a non-template deduction guide, if the arguments of A aren't
29987 deducible from the return type, don't add the candidate. */
29995 }
29998 }
30001 }
30003 /* Return artificial deduction guides built from the constructors of class
30004 template TMPL. */
30006 static tree
30008 {
30013 {
30018 }
30023 {
30024 /* Skip inherited constructors. */
30030 }
30032 /* Add implicit default constructor deduction guide. */
30034 {
30036 complain);
30038 }
30040 /* Add copy guide. */
30041 {
30044 complain);
30046 }
30049 }
30053 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30054 aggregate candidate is added separately because it depends on the
30055 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30056 guide. */
30058 static tree
30060 {
30063 {
30067 complain);
30068 }
30069 else
30070 {
30076 else
30078 }
30080 /* Cache the deduction guides for a template. We also remember the result of
30081 lookup, and rebuild everything if it changes; should be very rare. */
30085 {
30089 }
30090 else
30091 {
30094 }
30099 else
30100 {
30104 }
30108 }
30110 /* Return whether TMPL is a (class template argument-) deducible template. */
30112 bool
30114 {
30115 /* A deducible template is either a class template or is an alias template
30116 whose defining-type-id is of the form
30118 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30120 where the nested-name-specifier (if any) is non-dependent and the
30121 template-name of the simple-template-id names a deducible template. */
30132 }
30134 /* Deduce template arguments for the class template placeholder PTYPE for
30135 template TMPL based on the initializer INIT, and return the resulting
30136 type. */
30138 static tree
30141 {
30142 /* We should have handled this in the caller. */
30146 /* If the class was erroneous, don't try to deduce, because that
30147 can generate a lot of diagnostic. */
30153 /* Wait until the enclosing scope is non-dependent. */
30158 /* Initializing one placeholder from another. */
30169 {
30173 }
30175 {
30177 {
30178 /* Be permissive with equivalent alias templates. */
30181 bool complained
30183 "alias template deduction only available "
30188 {
30191 }
30192 }
30193 else
30195 }
30197 /* Wait until the initializer is non-dependent. */
30201 /* Don't bother with the alias rules for an equivalent template. */
30214 {
30219 {
30220 /* As an exception, the first phase in 16.3.1.7 (considering the
30221 initializer list as a single argument) is omitted if the
30222 initializer list consists of a single expression of type cv U,
30223 where U is a specialization of C or a class derived from a
30224 specialization of C. */
30228 }
30231 else
30233 }
30236 else
30239 /* Do this now to avoid problems with erroneous args later on. */
30249 /* Prune explicit deduction guides in copy-initialization context (but
30250 not copy-list-initialization). */
30253 {
30259 {
30260 /* Found a nonconverting guide, prune the candidates. */
30267 }
30268 }
30276 /* If this is list-initialization and the class has a list guide, first
30277 try deducing from the list as a single argument, as [over.match.list]. */
30279 {
30287 {
30288 /* That didn't work, now try treating the list as a sequence of
30289 arguments. */
30295 }
30296 }
30299 {
30301 " of %qT, as it has no non-explicit deduction guides or "
30304 }
30306 {
30310 }
30316 {
30318 {
30324 }
30326 }
30327 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30328 constructor is chosen, the initialization is ill-formed. */
30330 {
30332 {
30334 {
30335 // TODO: Pass down location from cp_finish_decl.
30337 "explicit deduction guide selected in "
30342 }
30344 }
30345 }
30347 /* If CTAD succeeded but the type doesn't have any explicit deduction
30348 guides, this deduction might not be what the user intended. */
30350 {
30354 "%qT may not intend to support class template argument "
30358 }
30362 }
30364 /* Return true if INIT is an unparenthesized id-expression or an
30365 unparenthesized class member access. Used for the argument of
30366 decltype(auto). */
30368 bool
30370 {
30373 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30374 reference type). Only the latter is an id-expression. */
30382 }
30384 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30385 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30386 The CONTEXT determines the context in which auto deduction is performed
30387 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30389 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30390 to properly substitute the result. It's also used in the adc_unify and
30391 adc_requirement contexts to communicate the necessary template arguments
30392 to satisfaction. OUTER_TARGS is ignored in other contexts.
30394 For partial-concept-ids, extra args may be appended to the list of deduced
30395 template arguments prior to determining constraint satisfaction. */
30397 tree
30401 {
30407 /* Defining a subset of type-dependent expressions that we can deduce
30408 from ahead of time isn't worth the trouble. */
30411 /* Similarly, we can't deduce from another undeduced decl. */
30415 /* We may be doing a partial substitution, but we still want to replace
30416 auto_node. */
30419 /* In C++23, we must deduce the type to int&& for code like
30420 decltype(auto) f(int&& x) { return (x); }
30421 or
30422 auto&& f(int x) { return x; }
30423 so we use treat_lvalue_as_rvalue_p. But don't do it for
30424 decltype(auto) f(int x) { return x; }
30425 where we should deduce 'int' rather than 'int&&'; transmogrifying
30426 INIT to an rvalue would break that. */
30427 tree r;
30437 /* C++17 class template argument deduction. */
30441 /* Nothing we can do with this, even in deduction context. */
30446 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30447 with either a new invented type template parameter U or, if the
30448 initializer is a braced-init-list (8.5.4), with
30449 std::initializer_list<U>. */
30451 {
30456 else
30457 {
30459 {
30463 "for deduction to %<std::initializer_list%>, use copy-"
30465 }
30467 }
30468 }
30474 {
30475 /* We don't recurse here because we can't deduce from a nested
30476 initializer_list. */
30480 }
30481 else
30484 tree targs;
30489 {
30490 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30491 and initializer has array type, deduce cv-qualified array type. */
30494 }
30496 {
30504 }
30505 else
30506 {
30511 tree tparms;
30515 else
30516 {
30520 }
30524 DEDUCE_CALL,
30527 {
30529 /* Try again at instantiation time. */
30533 /* If type is error_mark_node a diagnostic must have been
30534 emitted by now. Also, having a mention to '<type error>'
30535 in the diagnostic is not really useful to the user. */
30536 {
30539 && (auto_node
30543 init);
30544 else
30547 DEDUCE_CALL,
30549 }
30551 }
30552 }
30554 /* Check any placeholder constraints against the deduced type. */
30558 {
30560 {
30565 /* If the constraint is dependent, we need to wait until
30566 instantiation time to resolve the placeholder. */
30569 }
30576 {
30580 {
30581 /* As in satisfy_declaration_constraints. */
30585 else
30587 }
30588 }
30592 /* HACK: Compensate for callers not always communicating all levels of
30593 outer template arguments by filling in the outermost missing levels
30594 with dummy levels before checking satisfaction. We'll still crash
30595 if the constraint depends on a template argument belonging to one of
30596 these missing levels, but this hack otherwise allows us to handle a
30597 large subset of possible constraints (including all non-dependent
30598 constraints). */
30601 {
30606 }
30609 {
30611 {
30612 auto_diagnostic_group d;
30614 {
30632 }
30634 }
30636 }
30637 }
30640 /* The outer template arguments are already substituted into type
30647 }
30649 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
30650 result. */
30652 tree
30654 {
30656 {
30659 }
30663 {
30664 /* In an abbreviated function template we didn't know we were dealing
30665 with a function template when we saw the auto return type, so rebuild
30666 the return type using an auto with the correct level. */
30671 auto_vec);
30672 /* Also rebuild the constraint info in terms of the new auto. */
30680 }
30682 }
30684 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
30685 'decltype(auto)' or a deduced class template. */
30687 bool
30689 {
30694 else
30696 }
30698 /* for_each_template_parm callback for type_uses_auto. */
30700 int
30702 {
30704 }
30706 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
30707 a use of `auto'. Returns NULL_TREE otherwise. */
30709 tree
30711 {
30715 {
30716 /* The Concepts TS allows multiple autos in one type-specifier; just
30717 return the first one we find, do_auto_deduction will collect all of
30718 them. */
30722 else
30724 }
30725 else
30727 }
30729 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
30730 concepts are enabled, auto is acceptable in template arguments, but
30731 only when TEMPL identifies a template class. Return TRUE if any
30732 such errors were reported. */
30734 bool
30736 {
30738 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
30739 have already been rejected by the parser more generally. */
30742 /* If there were previous errors, nevermind. */
30746 /* If TMPL is an identifier, we're parsing and we can't tell yet
30747 whether TMPL is supposed to be a type, a function or a variable.
30748 We'll only be able to tell during template substitution, so we
30749 expect to be called again then. If concepts are enabled and we
30750 know we have a type, we're ok. */
30757 /* Quickly search for any occurrences of auto; usually there won't
30758 be any, and then we'll avoid allocating the vector. */
30766 {
30771 }
30774 }
30776 /* Recursively walk over && expressions searching for EXPR. Return a reference
30777 to that expression. */
30780 {
30784 {
30789 }
30791 }
30793 /* Convert the generic type parameters in PARM that match the types given in the
30794 range [START_IDX, END_IDX) from the current_template_parms into generic type
30795 packs. */
30797 tree
30799 {
30810 {
30811 /* Create a distinct parameter pack type from the current parm and add it
30812 to the replacement args to tsubst below into the generic function
30813 parameter. */
30827 /* Replace the current template parameter with new pack. */
30830 /* Surgically adjust the associated constraint of adjusted parameter
30831 and it's corresponding contribution to the current template
30832 requirements. */
30834 {
30840 /* If there was a constraint, we also need to replace that in
30841 the template requirements, which we've already built. */
30845 }
30846 }
30852 /* If there are more levels then build up the replacement with the outer
30853 template parms. */
30857 replacement);
30860 }
30862 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
30863 0..N-1. */
30865 void
30867 {
30870 integer_type_node,
30871 NULL_TREE),
30875 CP_BUILT_IN_INTEGER_PACK);
30876 }
30878 /* Walk the decl or type specialization table calling FN on each
30879 entry. */
30881 void
30885 {
30891 }
30893 /* Lookup the specialization of *ELT, in the decl or type
30894 specialization table. Return the SPEC that's already there, or
30895 NULL if nothing. */
30897 tree
30899 {
30909 }
30911 /* Return flags encoding whether SPEC is on the instantiation and/or
30912 specialization lists of TMPL. */
30914 unsigned
30916 {
30922 {
30925 }
30930 /* Only need to search if DECL is a partial specialization. */
30934 {
30937 }
30940 }
30942 /* Add a new specialization described by SPEC. DECL is the
30943 maybe-template decl and FLAGS is as returned from
30944 get_mergeable_specialization_flags. */
30946 void
30949 {
30952 {
30961 {
30964 }
30965 }
30968 {
30971 /* We don't distinguish different constrained partial type
30972 specializations, so there could be duplicates. Everything else
30973 must be new. */
30975 {
30981 }
30982 }
30989 {
30990 /* A partial specialization. */
30995 }
30996 }
30998 /* Set up the hash tables for template instantiations. */
31000 void
31002 {
31008 }
31010 /* Print stats about the template hash tables for -fstats. */
31012 void
31014 {
31023 }
31025 #if CHECKING_P
31029 /* Verify that build_non_dependent_expr () works, for various expressions,
31030 and that location wrappers don't affect the results. */
31032 static void
31034 {
31037 /* Verify constants, without and with location wrappers. */
31054 }
31056 /* Verify that type_dependent_expression_p () works correctly, even
31057 in the presence of location wrapper nodes. */
31059 static void
31061 {
31066 /* If no templates are involved, nothing is type-dependent. */
31072 /* Within a template, an unresolved name is always type-dependent. */
31075 /* Ensure it copes with NULL_TREE and errors. */
31079 /* A USING_DECL in a template should be type-dependent, even if wrapped
31080 with a location wrapper (PR c++/83799). */
31089 }
31091 /* Run all of the selftests within this file. */
31093 void
31095 {
31098 }