DR 1467 PR c++/51747

	DR 1467
	PR c++/51747
	* typeck2.c (digest_init_r): Fix single element list.

From-SVN: r222881

gcc/cp/ChangeLog

+2015-05-07  Jason Merrill  <jason@redhat.com>
+
+	DR 1467
+	PR c++/51747
+	* typeck2.c (digest_init_r): Fix single element list.
+
 2015-05-05  Jason Merrill  <jason@redhat.com>
 
 	* cp-gimplify.c (cp_genericize_r): Track TRY_BLOCK and

gcc/cp/typeck2.c

@@ -1096,6 +1096,19 @@ digest_init_r (tree type, tree init, bool nested, int flags,
 	      || TREE_CODE (type) == UNION_TYPE
 	      || TREE_CODE (type) == COMPLEX_TYPE);
 
+  /* "If T is a class type and the initializer list has a single
+     element of type cv U, where U is T or a class derived from T,
+     the object is initialized from that element."  */
+  if (cxx_dialect >= cxx11
+      && BRACE_ENCLOSED_INITIALIZER_P (init)
+      && CONSTRUCTOR_NELTS (init) == 1
+      && (CLASS_TYPE_P (type) || VECTOR_TYPE_P (type)))
+    {
+      tree elt = CONSTRUCTOR_ELT (init, 0)->value;
+      if (reference_related_p (type, TREE_TYPE (elt)))
+	init = elt;
+    }
+
   if (BRACE_ENCLOSED_INITIALIZER_P (init)
       && !TYPE_NON_AGGREGATE_CLASS (type))
     return process_init_constructor (type, init, complain);

gcc/testsuite/g++.dg/cpp0x/initlist95.C

+// PR c++/51747
+// { dg-do compile { target c++11 } }
+
+struct B {};
+struct D : B {D(B b) : B{b} {}};