diff --git a/resources/bytecode/javFiles/Bug298.jav b/resources/bytecode/javFiles/Bug298.jav
index 296ee028..42ff96a3 100644
--- a/resources/bytecode/javFiles/Bug298.jav
+++ b/resources/bytecode/javFiles/Bug298.jav
@@ -2,6 +2,7 @@ import java.util.List;
 import java.util.ArrayList;
 import java.lang.Integer;
 import java.lang.System;
+import java.lang.Boolean;
 import java.io.PrintStream;
 import java.util.stream.Stream;
 import java.util.function.Function;
@@ -10,5 +11,7 @@ public class Bug298 {
     public void m() {
         List<Integer> list = new ArrayList<>();
         list.stream().map(x -> 2 * x);
+
+        Function<Integer, Boolean> filter = x -> true;
     }
 }
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
index 262f764e..e318f737 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/RuleSet.java
@@ -14,6 +14,7 @@ import java.util.stream.Collectors;
 
 import de.dhbwstuttgart.core.JavaTXCompiler;
 import de.dhbwstuttgart.exceptions.DebugException;
+import de.dhbwstuttgart.syntaxtree.factory.UnifyTypeFactory;
 import de.dhbwstuttgart.syntaxtree.type.ExtendsWildcardType;
 import de.dhbwstuttgart.syntaxtree.type.RefType;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -905,7 +906,8 @@ public class RuleSet implements IRuleSet{
 
 			var fiArgs = fc.getFunctionalInterfaceTypeArguments(refType);
 			var retType = fiArgs.getFirst();
-			var lhsRet = lhsType.getTypeParams().get(0);
+			var lhsArgs = fc.getFunctionalInterfaceTypeArguments(lhsType);
+			var lhsRet = lhsArgs.getFirst();
 
 			Set<UnifyPair> result = new HashSet<>();
 			if (retType instanceof ExtendsType) {
@@ -917,7 +919,7 @@ public class RuleSet implements IRuleSet{
 			}
 
 			for (var i = 1; i < fiArgs.size(); i++) {
-				var lh = lhsType.getTypeParams().get(i);
+				var lh = lhsArgs.get(i);
 				var rh = fiArgs.get(i);
 
 				if (rh instanceof SuperType) {
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
index d87aedab..707d320f 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/interfaces/IFiniteClosure.java
@@ -75,7 +75,7 @@ public interface IFiniteClosure {
 	public Set<UnifyType> getAllTypesByName(String typeName);
 
 	public boolean isFunctionalInterface(ReferenceType t);
-	public List<UnifyType> getFunctionalInterfaceTypeArguments(ReferenceType t);
+	public List<UnifyType> getFunctionalInterfaceTypeArguments(UnifyType t);
 
 	public int compare(UnifyType rhsType, UnifyType rhsType2, PairOperator pairop);
 }
diff --git a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
index 81eac231..0dd832ac 100644
--- a/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
+++ b/src/main/java/de/dhbwstuttgart/typeinference/unify/model/FiniteClosure.java
@@ -612,7 +612,7 @@ implements IFiniteClosure  {
 	}
 
 	@Override
-	public List<UnifyType> getFunctionalInterfaceTypeArguments(ReferenceType t) {
+	public List<UnifyType> getFunctionalInterfaceTypeArguments(UnifyType t) {
 		var clazz = compiler.getClass(new JavaClassName(t.getName()));
 		var intfMethod = clazz.getMethods().stream().filter(m -> Modifier.isAbstract(m.modifier)).findFirst().orElseThrow();
 
@@ -630,6 +630,7 @@ implements IFiniteClosure  {
 			i += 1;
 		}
 
+		System.out.println(args);
 		return args;
 	}