Index: gcc/testsuite/g++.dg/inherit/virtual1.C
===================================================================
--- gcc/testsuite/g++.dg/inherit/virtual1.C	(revision 0)
+++ gcc/testsuite/g++.dg/inherit/virtual1.C	(revision 0)
@@ -0,0 +1,12 @@
+//PR c++/27952
+
+struct A
+{
+    virtual ~A() {}
+};
+
+struct B : A, virtual A {};     // { dg-error "duplicate base|forward declaration" }
+
+struct C : A, B {};             // { dg-error "duplicate base|invalid use" }
+
+C c;                            // { dg-error "aggregate" }
Index: gcc/cp/decl.c
===================================================================
--- gcc/cp/decl.c	(revision 117730)
+++ gcc/cp/decl.c	(working copy)
@@ -9779,9 +9779,12 @@ xref_tag_from_type (tree old, tree id, t
 /* Create the binfo hierarchy for REF with (possibly NULL) base list
    BASE_LIST.  For each element on BASE_LIST the TREE_PURPOSE is an
    access_* node, and the TREE_VALUE is the type of the base-class.
-   Non-NULL TREE_TYPE indicates virtual inheritance.  */
+   Non-NULL TREE_TYPE indicates virtual inheritance.  
+ 
+   Returns true if the binfo heirarchy was successfully created,
+   false if an error was detected. */
 
-void
+bool
 xref_basetypes (tree ref, tree base_list)
 {
   tree *basep;
@@ -9793,7 +9796,7 @@ xref_basetypes (tree ref, tree base_list
   tree igo_prev; /* Track Inheritance Graph Order.  */
 
   if (ref == error_mark_node)
-    return;
+    return false;
 
   /* The base of a derived class is private by default, all others are
      public.  */
@@ -9845,13 +9848,19 @@ xref_basetypes (tree ref, tree base_list
       CLASSTYPE_NON_AGGREGATE (ref) = 1;
 
       if (TREE_CODE (ref) == UNION_TYPE)
-	error ("derived union %qT invalid", ref);
+        {
+	  error ("derived union %qT invalid", ref);
+          return false;
+        }
     }
 
   if (max_bases > 1)
     {
       if (TYPE_FOR_JAVA (ref))
-	error ("Java class %qT cannot have multiple bases", ref);
+        {
+	  error ("Java class %qT cannot have multiple bases", ref);
+          return false;
+        }
     }
 
   if (max_vbases)
@@ -9859,7 +9868,10 @@ xref_basetypes (tree ref, tree base_list
       CLASSTYPE_VBASECLASSES (ref) = VEC_alloc (tree, gc, max_vbases);
 
       if (TYPE_FOR_JAVA (ref))
-	error ("Java class %qT cannot have virtual bases", ref);
+        {
+	  error ("Java class %qT cannot have virtual bases", ref);
+          return false;
+        }
     }
 
   for (igo_prev = binfo; base_list; base_list = TREE_CHAIN (base_list))
@@ -9880,7 +9892,7 @@ xref_basetypes (tree ref, tree base_list
 	{
 	  error ("base type %qT fails to be a struct or class type",
 		 basetype);
-	  continue;
+	  return false;
 	}
 
       if (TYPE_FOR_JAVA (basetype) && (current_lang_depth () == 0))
@@ -9914,7 +9926,7 @@ xref_basetypes (tree ref, tree base_list
 	    error ("recursive type %qT undefined", basetype);
 	  else
 	    error ("duplicate base type %qT invalid", basetype);
-	  continue;
+	  return false;
 	}
       TYPE_MARKED_P (basetype) = 1;
 
@@ -9957,6 +9969,8 @@ xref_basetypes (tree ref, tree base_list
 	else
 	  break;
     }
+
+  return true;
 }
 
 
Index: gcc/cp/cp-tree.h
===================================================================
--- gcc/cp/cp-tree.h	(revision 117730)
+++ gcc/cp/cp-tree.h	(working copy)
@@ -3909,7 +3909,7 @@ extern int grok_ctor_properties			(tree,
 extern bool grok_op_properties			(tree, bool);
 extern tree xref_tag				(enum tag_types, tree, tag_scope, bool);
 extern tree xref_tag_from_type			(tree, tree, tag_scope);
-extern void xref_basetypes			(tree, tree);
+extern bool xref_basetypes			(tree, tree);
 extern tree start_enum				(tree);
 extern void finish_enum				(tree);
 extern void build_enumerator			(tree, tree, tree);
Index: gcc/cp/parser.c
===================================================================
--- gcc/cp/parser.c	(revision 117730)
+++ gcc/cp/parser.c	(working copy)
@@ -13440,7 +13440,8 @@ cp_parser_class_head (cp_parser* parser,
     bases = cp_parser_base_clause (parser);
 
   /* Process the base classes.  */
-  xref_basetypes (type, bases);
+  if (!xref_basetypes (type, bases))
+    type = NULL_TREE;
 
  done:
   /* Leave the scope given by the nested-name-specifier.  We will