[gcc r10-9849] c++: using overloaded with local decl [PR92918]

[Jason Merrill <jason@gcc.gnu.org>]

https://gcc.gnu.org/g:decd38f99dd05eb54ddcaee7c52f21a56a844613

commit r10-9849-gdecd38f99dd05eb54ddcaee7c52f21a56a844613
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Apr 7 14:55:48 2021 -0400

    c++: using overloaded with local decl [PR92918]
    
    The problem here was that the lookup for 'impl' when parsing the template
    only found the using-declaration, not the member function declaration.
    
    This happened because when trying to add the member function declaration,
    push_class_level_binding_1 saw that the current binding was a USING_DECL and
    the new value is an overload, and decided to just return success.
    
    That 'return true' dates back to r69921.  In
    https://gcc.gnu.org/pipermail/gcc-patches/2003-July/110632.html Nathan
    mentions that we only push dependent USING_DECLs, which is no longer the
    case; now that we retain more USING_DECLs, handling this case like the other
    overloaded function cases seems like the obvious solution.
    
    gcc/cp/ChangeLog:
    
            PR c++/92918
            * name-lookup.c (push_class_level_binding_1): Do overload a new
            function with a previous using-declaration.
    
    gcc/testsuite/ChangeLog:
    
            PR c++/92918
            * g++.dg/lookup/using66.C: New test.

Diff:
---
 gcc/cp/name-lookup.c                  |  2 +-
 gcc/testsuite/g++.dg/lookup/using66.C | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 533d79542c9..f8caa16fc76 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4552,7 +4552,7 @@ push_class_level_binding_1 (tree name, tree x)
 	old_decl = bval;
       else if (TREE_CODE (bval) == USING_DECL
 	       && OVL_P (target_decl))
-	return true;
+	old_decl = bval;
       else if (OVL_P (target_decl)
 	       && OVL_P (target_bval))
 	old_decl = bval;
diff --git a/gcc/testsuite/g++.dg/lookup/using66.C b/gcc/testsuite/g++.dg/lookup/using66.C
new file mode 100644
index 00000000000..02383bbea3e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lookup/using66.C
@@ -0,0 +1,23 @@
+// PR c++/92918
+// { dg-do compile { target c++11 } }
+
+struct Base03
+{
+    static void impl();
+};
+
+struct Problem : Base03
+{
+    using Base03::impl;
+    static int impl(char const *);
+
+    template <typename T>
+    auto f(const T &t) const
+    -> decltype(impl(t))
+    {
+        return impl(t);
+    }
+};
+
+Problem t;
+int i = t.f("42");