diff --git a/src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java b/src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java
index 92f20b9d..3816e12d 100644
--- a/src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java
+++ b/src/main/java/de/dhbwstuttgart/target/generate/StatementToTargetExpression.java
@@ -208,8 +208,9 @@ public class StatementToTargetExpression implements ASTVisitor {
         var isPrivate = false;
         var signature = methodCall.signatureArguments().stream().map(converter::convert).toList();
 
-        var receiverClass = converter.compiler.getClass(new JavaClassName(converter.convert(methodCall.receiver.getType()).name()));
+        var receiverClass = converter.compiler.getClass(receiverName);
         if (methodCall.receiver instanceof ExpressionReceiver expressionReceiver && expressionReceiver.expr instanceof This) {
+            if (receiverClass == null) throw new DebugException("Class " + receiverName + " does not exist!");
             var thisMethod = converter.findMethod(receiverClass, methodCall.name, signature);
             ClassOrInterface finalReceiverClass = receiverClass;
             foundMethod = thisMethod.orElseGet(() -> findMethod(finalReceiverClass.getSuperClass().getName(), methodCall.name, signature).orElseThrow());