Fixed possible cast exception.

ICSharpCode.NRefactory.CSharp/Parser/CSharpParser.cs

@@ -693,7 +693,12 @@ namespace ICSharpCode.NRefactory.CSharp
 					newType.AddChild(new CSharpTokenNode(Convert(location [curLoc++])), Roles.LBrace);
 				typeStack.Push(newType);
 				
-				foreach (EnumMember member in e.Members) {
+				foreach (var m in e.Members) {
+					EnumMember member = m as EnumMember;
+					if (member == null) {
+						Console.WriteLine("WARNING - ENUM MEMBER: " + m);
+						continue;
+					}
 					Visit(member);
 					if (location != null && curLoc < location.Count - 1) //last one is closing brace
 						newType.AddChild(new CSharpTokenNode(Convert(location [curLoc++])), Roles.Comma);