diff --git a/ARMeilleure/Decoders/InstDescriptor.cs b/ARMeilleure/Decoders/InstDescriptor.cs
index ee2b1c2e..29966d6d 100644
--- a/ARMeilleure/Decoders/InstDescriptor.cs
+++ b/ARMeilleure/Decoders/InstDescriptor.cs
@@ -4,7 +4,7 @@ namespace ARMeilleure.Decoders
 {
     struct InstDescriptor
     {
-        public static InstDescriptor Undefined => new InstDescriptor(InstName.Und, null);
+        public static InstDescriptor Undefined => new InstDescriptor(InstName.Und, InstEmit.Und);
 
         public InstName    Name    { get; }
         public InstEmitter Emitter { get; }