diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 91aa756..6d8573b 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -346,8 +346,9 @@ void XMLUtil::ConvertUTF32ToUTF8( unsigned long input, char* output, int* length
         case 1:
             --output;
             *output = (char)(input | FIRST_BYTE_MARK[*length]);
-        default:
             break;
+        default:
+            TIXMLASSERT( false );
     }
 }