1 files changed, 9 insertions, 0 deletions
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 30323f0..4616d8d 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -370,6 +370,15 @@ build_base_path (enum tree_code code,
       goto indout;
     }
 
+  if (!COMPLETE_TYPE_P (probe))
+    {
+      if (complain & tf_error)
+	error ("cannot convert from %qT to base class %qT because %qT is "
+	       "incomplete", BINFO_TYPE (d_binfo), BINFO_TYPE (binfo),
+	       BINFO_TYPE (d_binfo));
+      return error_mark_node;
+    }
+
   /* If we're in an NSDMI, we don't have the full constructor context yet
      that we need for converting to a virtual base, so just build a stub
      CONVERT_EXPR and expand it later in bot_replace.  */