diff --git a/tutorial/go/src/handler.go b/tutorial/go/src/handler.go
index fb0daef..1763832 100644
--- a/tutorial/go/src/handler.go
+++ b/tutorial/go/src/handler.go
@@ -59,7 +59,7 @@
 	case tutorial.Operation_DIVIDE:
 		if w.Num2 == 0 {
 			ouch := tutorial.NewInvalidOperation()
-			ouch.What = int32(w.Op)
+			ouch.WhatOp = int32(w.Op)
 			ouch.Why = "Cannot divide by 0"
 			err = ouch
 			return
@@ -68,7 +68,7 @@
 		break
 	default:
 		ouch := tutorial.NewInvalidOperation()
-		ouch.What = int32(w.Op)
+		ouch.WhatOp = int32(w.Op)
 		ouch.Why = "Unknown operation"
 		err = ouch
 		return