diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
index 8eb49691..f1e3b7a7 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java
@@ -19,6 +19,8 @@ import java.util.function.BinaryOperator;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import de.dhbwstuttgart.exceptions.TypeinferenceException;
+import de.dhbwstuttgart.parser.NullToken;
 import de.dhbwstuttgart.syntaxtree.factory.UnifyTypeFactory;
 import de.dhbwstuttgart.typeinference.constraints.Constraint;
 import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
@@ -228,7 +230,9 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		catch (IOException ioE) {
 			System.err.println("no log-File");
 		}
-		if (isUndefinedPairSetSet(res)) { return new HashSet<>(); }
+		if (isUndefinedPairSetSet(res)) { 
+				throw new TypeinferenceException("Unresolved constraints: " + res.toString(), new NullToken()); //return new HashSet<>(); 
+			}
 		else return res;
 	}
 /*	
@@ -478,15 +482,16 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 																			  //PL 2018-05-18 beide Bedingungen muessen gelten, da eqPrime Veränderungen in allem ausser subst
 																			  //eqPrimePrime Veraenderungen in subst repraesentieren.
 					//try {
-						if (isSolvedForm(eqPrime)) {
-							writeLog("eqPrime:" + eqPrime.toString()+"\n");
-						}
+						//if (isSolvedForm(eqPrime)) {
+						//	writeLog("eqPrime:" + eqPrime.toString()+"\n");
+						//}
 					//}
 					//catch (IOException e) { 
 					//	System.err.println("log-File nicht vorhanden");
 					//}
 					eqPrimePrimeSet.add(eqPrime);
-					if (finalresult) { 
+					if (finalresult && isSolvedForm(eqPrime)) { 
+						writeLog("eqPrime:" + eqPrime.toString()+"\n");
 						urm.notify(eqPrimePrimeSet);
 					}
 				}
diff --git a/src/test/resources/bytecode/javFiles/Id.jav b/src/test/resources/bytecode/javFiles/Id.jav
index 43718582..a8d85dfd 100644
--- a/src/test/resources/bytecode/javFiles/Id.jav
+++ b/src/test/resources/bytecode/javFiles/Id.jav
@@ -1,6 +1,6 @@
 public class Id {
 	
-	<A> id(A b){
+	<A extends B, B> B id(A b){
 		return b;
 	}
 }