https://gcc.gnu.org/g:2196a20b82bdde2aeb099bcfd164fa29a698e837
commit r15-3939-g2196a20b82bdde2aeb099bcfd164fa29a698e837
Author: Nathaniel Shead <nathanielosh...@gmail.com>
Date: Fri Sep 20 00:47:12 2024 +1000
c++: Implement resolution for DR 36 [PR116160]
This implements part of P1787 to no longer complain about redeclaring an
entity via using-decl other than in a class scope.
PR c++/116160
gcc/cp/ChangeLog:
* name-lookup.cc (supplement_binding): Allow redeclaration via
USING_DECL if not in class scope.
(do_nonmember_using_decl): Remove function-scope exemption.
(push_using_decl_bindings): Remove outdated comment.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/using-enum-3.C: No longer expect an error.
* g++.dg/lookup/using53.C: Remove XFAIL.
* g++.dg/cpp2a/using-enum-11.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
Reviewed-by: Jason Merrill <ja...@redhat.com>
Diff:
---
gcc/cp/name-lookup.cc | 12 +++++++-----
gcc/testsuite/g++.dg/cpp0x/using-enum-3.C | 2 +-
gcc/testsuite/g++.dg/cpp2a/using-enum-11.C | 9 +++++++++
gcc/testsuite/g++.dg/lookup/using53.C | 2 +-
4 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index a2f94e0f363e..4754ef5a5229 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -2874,6 +2874,12 @@ supplement_binding (cxx_binding *binding, tree decl)
"%<-std=c++2c%> or %<-std=gnu++2c%>");
binding->value = name_lookup::ambiguous (decl, binding->value);
}
+ else if (binding->scope->kind != sk_class
+ && TREE_CODE (decl) == USING_DECL
+ && decls_match (target_bval, target_decl))
+ /* Since P1787 (DR 36) it is OK to redeclare entities via using-decl,
+ except in class scopes. */
+ ok = false;
else
{
if (!error_operand_p (bval))
@@ -5377,8 +5383,7 @@ do_nonmember_using_decl (name_lookup &lookup, bool
fn_scope_p,
else if (value
/* Ignore anticipated builtins. */
&& !anticipated_builtin_p (value)
- && (fn_scope_p
- || !decls_match (lookup.value, strip_using_decl (value))))
+ && !decls_match (lookup.value, strip_using_decl (value)))
{
diagnose_name_conflict (lookup.value, value);
failed = true;
@@ -6651,9 +6656,6 @@ push_using_decl_bindings (name_lookup *lookup, tree name,
tree value)
type = binding->type;
}
- /* DR 36 questions why using-decls at function scope may not be
- duplicates. Disallow it, as C++11 claimed and PR 20420
- implemented. */
if (lookup)
do_nonmember_using_decl (*lookup, true, true, &value, &type);
diff --git a/gcc/testsuite/g++.dg/cpp0x/using-enum-3.C
b/gcc/testsuite/g++.dg/cpp0x/using-enum-3.C
index 34f8bf4fa0bb..4638181c63ce 100644
--- a/gcc/testsuite/g++.dg/cpp0x/using-enum-3.C
+++ b/gcc/testsuite/g++.dg/cpp0x/using-enum-3.C
@@ -9,7 +9,7 @@
void f ()
{
enum e { a };
- using e::a; // { dg-error "redeclaration" }
+ using e::a; // { dg-bogus "redeclaration" "P1787" }
// { dg-error "enum" "" { target { ! c++2a } } .-1 }
}
diff --git a/gcc/testsuite/g++.dg/cpp2a/using-enum-11.C
b/gcc/testsuite/g++.dg/cpp2a/using-enum-11.C
new file mode 100644
index 000000000000..ff99ed422d5f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/using-enum-11.C
@@ -0,0 +1,9 @@
+// PR c++/116160
+// { dg-do compile { target c++20 } }
+
+enum class Blah { b };
+void foo() {
+ using Blah::b;
+ using Blah::b;
+ using enum Blah;
+}
diff --git a/gcc/testsuite/g++.dg/lookup/using53.C
b/gcc/testsuite/g++.dg/lookup/using53.C
index e91829e939a9..8279c73bfc4f 100644
--- a/gcc/testsuite/g++.dg/lookup/using53.C
+++ b/gcc/testsuite/g++.dg/lookup/using53.C
@@ -52,5 +52,5 @@ void
f ()
{
using N::i;
- using N::i; // { dg-bogus "conflicts" "See P1787 (CWG36)" { xfail
*-*-* } }
+ using N::i; // { dg-bogus "conflicts" "See P1787 (CWG36)" }
}
