Implement new C++ intrinsics __is_assignable and __is_constructible.

c-family/

Implement new C++ intrinsics __is_assignable and __is_constructible.
* c-common.c (__is_assignable, __is_constructible): New.
* c-common.h (RID_IS_ASSIGNABLE, RID_IS_CONSTRUCTIBLE): Likewise.

cp/

PR c++/80654
PR c++/80682
Implement new C++ intrinsics __is_assignable and __is_constructible.
* cp-tree.h (CPTK_IS_ASSIGNABLE, CPTK_IS_CONSTRUCTIBLE): New.
(is_xible): New.
* cxx-pretty-print.c (pp_cxx_trait_expression): Handle
CPTK_IS_ASSIGNABLE and CPTK_IS_CONSTRUCTIBLE.
* method.c (constructible_expr): Set cp_unevaluated.
(is_xible_helper): New.
(is_trivially_xible): Adjust.
(is_xible): New.
* parser.c (cp_parser_primary_expression): Handle
RID_IS_ASSIGNABLE and RID_IS_CONSTRUCTIBLE.
(cp_parser_trait_expr): Likewise.
* semantics.c (trait_expr_value): Handle
CPTK_IS_ASSIGNABLE and CPTK_IS_CONSTRUCTIBLE.

testsuite/

* g++.dg/ext/80654.C: New.

libstdc++-v3/

Implement new C++ intrinsics __is_assignable and __is_constructible.
* include/std/type_traits (__do_is_static_castable_impl): Remove.
(__is_static_castable_impl, __is_static_castable_safe): Likewise.
(__is_static_castable, __do_is_direct_constructible_impl): Likewise.
(__is_direct_constructible_impl): Likewise.
(__is_direct_constructible_new_safe): Likewise.
(__is_base_to_derived_ref, __is_lvalue_to_rvalue_ref): Likewise.
(__is_direct_constructible_ref_cast): Likewise.
(__is_direct_constructible_new, __is_direct_constructible): Likewise.
(__do_is_nary_constructible_impl): Likewise.
(__is_nary_constructible_impl, __is_nary_constructible): Likewise.
(__is_constructible_impl): Likewise.
(is_constructible): Call the intrinsic.
(__is_assignable_helper): Remove.
(is_assignable): Call the intrinsic.
(is_trivially_constructible): Likewise.
(__is_trivially_copy_constructible_impl): New.
(is_trivially_copy_constructible): Use it.
(__is_trivially_move_constructible_impl): New.
(is_trivially_move_constructible): Use it.
(is_trivially_assignable): Call the intrinsic.
(__is_trivially_copy_assignable_impl): New.
(is_trivially_copy_assignable): Use it.
(__is_trivially_move_assignable_impl): New.
(is_trivially_move_assignable): Use it.
(testsuite/20_util/declval/requirements/1_neg.cc): Adjust.
(testsuite/20_util/is_trivially_copy_assignable/value.cc):
Add test for void.
(testsuite/20_util/is_trivially_copy_constructible/value.cc): Likewise.
(testsuite/20_util/is_trivially_move_assignable/value.cc): Likewise.
(testsuite/20_util/is_trivially_move_constructible/value.cc): Likewise.
(testsuite/20_util/make_signed/requirements/typedefs_neg.cc): Adjust.
(testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc):
Likewise.

From-SVN: r248153

1 files changed, 35 insertions, 7 deletions

diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 9898ff1..756b59d 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -1162,6 +1162,7 @@ constructible_expr (tree to, tree from)
     {
       tree ctype = to;
       vec<tree, va_gc> *args = NULL;
+      cp_unevaluated cp_uneval_guard;
       if (TREE_CODE (to) != REFERENCE_TYPE)
 	to = cp_build_reference_type (to, /*rval*/false);
       tree ob = build_stub_object (to);
@@ -1198,22 +1199,36 @@ constructible_expr (tree to, tree from)
   return expr;
 }
 
-/* Returns true iff TO is trivially assignable (if CODE is MODIFY_EXPR) or
+/* Returns a tree iff TO is assignable (if CODE is MODIFY_EXPR) or
    constructible (otherwise) from FROM, which is a single type for
    assignment or a list of types for construction.  */
 
-bool
-is_trivially_xible (enum tree_code code, tree to, tree from)
+static tree
+is_xible_helper (enum tree_code code, tree to, tree from, bool trivial)
 {
-  if (VOID_TYPE_P (to))
-    return false;
+  if (VOID_TYPE_P (to) || ABSTRACT_CLASS_TYPE_P (to)
+      || (from && FUNC_OR_METHOD_TYPE_P (from)
+	  && (TYPE_READONLY (from) || FUNCTION_REF_QUALIFIED (from))))
+    return error_mark_node;
   tree expr;
   if (code == MODIFY_EXPR)
     expr = assignable_expr (to, from);
-  else if (from && TREE_CHAIN (from))
-    return false; // only 0- and 1-argument ctors can be trivial
+  else if (trivial && from && TREE_CHAIN (from))
+    return error_mark_node; // only 0- and 1-argument ctors can be trivial
   else
     expr = constructible_expr (to, from);
+  return expr;
+}
+
+/* Returns true iff TO is trivially assignable (if CODE is MODIFY_EXPR) or
+   constructible (otherwise) from FROM, which is a single type for
+   assignment or a list of types for construction.  */
+
+bool
+is_trivially_xible (enum tree_code code, tree to, tree from)
+{
+  tree expr;
+  expr = is_xible_helper (code, to, from, /*trivial*/true);
 
   if (expr == error_mark_node)
     return false;
@@ -1221,6 +1236,19 @@ is_trivially_xible (enum tree_code code, tree to, tree from)
   return !nt;
 }
 
+/* Returns true iff TO is assignable (if CODE is MODIFY_EXPR) or
+   constructible (otherwise) from FROM, which is a single type for
+   assignment or a list of types for construction.  */
+
+bool
+is_xible (enum tree_code code, tree to, tree from)
+{
+  tree expr = is_xible_helper (code, to, from, /*trivial*/false);
+  if (expr == error_mark_node)
+    return false;
+  return !!expr;
+}
+
 /* Subroutine of synthesized_method_walk.  Update SPEC_P, TRIVIAL_P and
    DELETED_P or give an error message MSG with argument ARG.  */