diff --git a/mcs/mcs/membercache.cs b/mcs/mcs/membercache.cs
index 0dabf85b80f69..8321d29d09bc1 100644
--- a/mcs/mcs/membercache.cs
+++ b/mcs/mcs/membercache.cs
@@ -486,9 +486,14 @@ public static MemberSpec FindBaseMember (MemberCore member, out MemberSpec bestC
 		{
 			bestCandidate = null;
 			var container = member.Parent.PartialContainer.Definition;
-			if (!container.IsInterface)
+			if (!container.IsInterface) {
 				container = container.BaseType;
 
+				// It can happen for a user definition of System.Object
+				if (container == null)
+					return null;
+			}
+
 			string name = GetLookupName (member);
 			IList<MemberSpec> applicable;
 			var member_param = member is IParametersMember ? ((IParametersMember) member).Parameters : null;
diff --git a/mcs/tests/test-616.cs b/mcs/tests/test-616.cs
index a2804a9c1c7d8..00fe6db9023cb 100644
--- a/mcs/tests/test-616.cs
+++ b/mcs/tests/test-616.cs
@@ -6,7 +6,10 @@
 
 namespace System
 {
-	public class Object {}
+	public class Object
+	{
+		object value_with_no_base;
+	}
 		
 	public struct Byte {}
 	public struct Int16 {}