* class.c (add_method): Allow using-declarations to coexist.

From-SVN: r241620

gcc/cp/ChangeLog

@@ -1,3 +1,7 @@
+2016-10-26  Jason Merrill  <jason@redhat.com>
+
+	* class.c (add_method): Allow using-declarations to coexist.
+
 2016-10-25  Jason Merrill  <jason@redhat.com>
 
 	* constexpr.c (maybe_constant_init): Pull out TARGET_EXPR_INITIAL.

gcc/cp/class.c

@@ -1094,6 +1094,11 @@ add_method (tree type, tree method, tree using_decl)
       if (TREE_CODE (fn) != TREE_CODE (method))
 	continue;
 
+      /* Two using-declarations can coexist, we'll complain about ambiguity in
+	 overload resolution.  */
+      if (using_decl && TREE_CODE (fns) == OVERLOAD && OVL_USED (fns))
+	continue;
+
       /* [over.load] Member function declarations with the
 	 same name and the same parameter types cannot be
 	 overloaded if any of them is a static member

gcc/testsuite/g++.dg/overload/using4.C

@@ -0,0 +1,19 @@
+struct A
+{
+  void f();
+};
+
+struct B
+{
+  void f();
+};
+
+struct C: A,B {
+  using A::f;
+  using B::f;
+};
+
+int main()
+{
+  C().f();			// { dg-error "ambiguous" }
+}