diff --git a/src/main/java/edu/kit/typicalc/model/Tree.java b/src/main/java/edu/kit/typicalc/model/Tree.java
index 650f343..f70bec8 100644
--- a/src/main/java/edu/kit/typicalc/model/Tree.java
+++ b/src/main/java/edu/kit/typicalc/model/Tree.java
@@ -41,7 +41,7 @@ public class Tree implements TermVisitorTree {
      * @param lambdaTerm the lambda term to generate the tree for
      */
     protected Tree(Map<VarTerm, TypeAbstraction> typeAssumptions, LambdaTerm lambdaTerm) {
-        this(typeAssumptions, lambdaTerm, new TypeVariableFactory(TypeVariableKind.TREE));
+        this(typeAssumptions, lambdaTerm, new TypeVariableFactory(TypeVariableKind.TREE), false);
     }
 
     /**
@@ -54,13 +54,14 @@ public class Tree implements TermVisitorTree {
      * @param typeAssumptions the type assumptions to consider when generating the tree
      * @param lambdaTerm the lambda term to generate the tree for
      * @param typeVariableFactory the type variable factory to use
+     * @param partOfLetTerm indicates whether the tree is generated for a sub-inference that is part of a let term
      */
     protected Tree(Map<VarTerm, TypeAbstraction> typeAssumptions, LambdaTerm lambdaTerm,
-                   TypeVariableFactory typeVariableFactory) {
+                   TypeVariableFactory typeVariableFactory, boolean partOfLetTerm) {
         this.typeVarFactory = typeVariableFactory;
         this.constraints = new ArrayList<>();
 
-        this.stepFactory = lambdaTerm.hasLet() ? new StepFactoryWithLet() : new StepFactoryDefault();
+        this.stepFactory = lambdaTerm.hasLet() || partOfLetTerm ? new StepFactoryWithLet() : new StepFactoryDefault();
 
         this.firstTypeVariable = typeVarFactory.nextTypeVariable();
         this.firstInferenceStep = lambdaTerm.accept(this, typeAssumptions, firstTypeVariable);
diff --git a/src/main/java/edu/kit/typicalc/model/TypeInfererLet.java b/src/main/java/edu/kit/typicalc/model/TypeInfererLet.java
index 53a7620..840a70e 100644
--- a/src/main/java/edu/kit/typicalc/model/TypeInfererLet.java
+++ b/src/main/java/edu/kit/typicalc/model/TypeInfererLet.java
@@ -27,12 +27,12 @@ public class TypeInfererLet implements TypeInfererInterface {
      *
      * @param lambdaTerm      the lambda term to generate the tree for
      * @param typeAssumptions the type assumptions to consider when generating the tree
-     * @param typeVarFactory the type variable factory that should be used in this inference to guarantee consistecy
+     * @param typeVarFactory the type variable factory that should be used in this inference to guarantee consistency
      *                       with the outer inference
      */
     protected TypeInfererLet(LambdaTerm lambdaTerm, Map<VarTerm, TypeAbstraction> typeAssumptions,
                              TypeVariableFactory typeVarFactory) {
-        tree = new Tree(typeAssumptions, lambdaTerm, typeVarFactory);
+        tree = new Tree(typeAssumptions, lambdaTerm, typeVarFactory, true);
 
         // cancel algorithm if a sub-inference failed
         if (tree.hasFailedSubInference()) {
diff --git a/src/test/java/edu/kit/typicalc/model/TreeTest.java b/src/test/java/edu/kit/typicalc/model/TreeTest.java
index 4aa6d62..a6d2209 100644
--- a/src/test/java/edu/kit/typicalc/model/TreeTest.java
+++ b/src/test/java/edu/kit/typicalc/model/TreeTest.java
@@ -40,7 +40,7 @@ class TreeTest {
             factory.nextTypeVariable();
             factoryRef.nextTypeVariable();
         }
-        Tree tree = new Tree(TYPE_ASSUMPTIONS, VAR, factory);
+        Tree tree = new Tree(TYPE_ASSUMPTIONS, VAR, factory, false);
         assertEquals(tree.getFirstTypeVariable(), factoryRef.nextTypeVariable());
     }