* class.c (one_inheriting_sig): Don't inherit base copy ctors.

From-SVN: r193623

gcc/cp/ChangeLog

 2012-11-19  Jason Merrill  <jason@redhat.com>
 
+	* class.c (one_inheriting_sig): Don't inherit base copy ctors.
+
 	PR c++/55262
 	* method.c (implicitly_declare_fn): Set DECL_PARM_INDEX on
 	the parms of an inheriting ctor.

gcc/cp/class.c

@@ -2886,15 +2886,19 @@ static void
 one_inheriting_sig (tree t, tree ctor, tree *parms, int nparms)
 {
   /* We don't declare an inheriting ctor that would be a default,
-     copy or move ctor.  */
-  if (nparms == 0
-      || (nparms == 1
-	  && TREE_CODE (parms[0]) == REFERENCE_TYPE
-	  && TYPE_MAIN_VARIANT (TREE_TYPE (parms[0])) == t))
+     copy or move ctor for derived or base.  */
+  if (nparms == 0)
     return;
-  int i;
+  if (nparms == 1
+      && TREE_CODE (parms[0]) == REFERENCE_TYPE)
+    {
+      tree parm = TYPE_MAIN_VARIANT (TREE_TYPE (parms[0]));
+      if (parm == t || parm == DECL_CONTEXT (ctor))
+	return;
+    }
+
   tree parmlist = void_list_node;
-  for (i = nparms - 1; i >= 0; i--)
+  for (int i = nparms - 1; i >= 0; i--)
     parmlist = tree_cons (NULL_TREE, parms[i], parmlist);
   tree fn = implicitly_declare_fn (sfk_inheriting_constructor,
 				   t, false, ctor, parmlist);

gcc/testsuite/g++.dg/cpp0x/inh-ctor15.C

+// Discussions on the core reflector indicate that not inheriting base copy
+// constructors was a deliberate choice.
+
+// { dg-options -std=c++11 }
+
+struct A { A(int); };
+struct B: public A
+{
+  using A::A;
+};
+
+A a (42);
+
+B b1 (24);			// inherited
+B b2 (a);			// not inherited { dg-error "no match" }