diff --git a/evaluator/evaluator.go b/evaluator/evaluator.go
index 758f4dd..313ed4a 100644
--- a/evaluator/evaluator.go
+++ b/evaluator/evaluator.go
@@ -45,7 +45,7 @@ func Eval(node ast.Node, env *object.Environment) object.Object {
 			return left
 		}
 		right := Eval(node.Right, env)
-		if isError(right) {
+		if isError(right) && right != nil {
 			return right
 		}
 		return evalInfixExpression(node.Operator, left, right, node.Token.Line)
diff --git a/evaluator/infix.go b/evaluator/infix.go
index f25ef9d..d11d867 100644
--- a/evaluator/infix.go
+++ b/evaluator/infix.go
@@ -8,6 +8,9 @@ import (
 )
 
 func evalInfixExpression(operator string, left, right object.Object, line int) object.Object {
+	if right == nil {
+		return newError("Mstari %d: Umekosea hapa", line)
+			}
 	if left == nil {
 		return newError("Mstari %d: Umekosea hapa", line)
 	}