diff --git a/vadl/main/vadl/ast/TypeChecker.java b/vadl/main/vadl/ast/TypeChecker.java
index 87af42f54..737755b11 100644
--- a/vadl/main/vadl/ast/TypeChecker.java
+++ b/vadl/main/vadl/ast/TypeChecker.java
@@ -1762,14 +1762,14 @@ public Void visit(ModelDefinition definition) {
 
   @Override
   public Void visit(RecordTypeDefinition definition) {
-    throwUnimplemented(definition);
-    return null;
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(definition.getClass().getSimpleName()));
   }
 
   @Override
   public Void visit(ModelTypeDefinition definition) {
-    throwUnimplemented(definition);
-    return null;
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(definition.getClass().getSimpleName()));
   }
 
   @Override
@@ -1814,9 +1814,9 @@ public Void visit(Parameter definition) {
   }
 
   @Override
-  public Void visit(GroupDefinition groupDefinition) {
-    throwUnimplemented(groupDefinition);
-    return null;
+  public Void visit(GroupDefinition definition) {
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(definition.getClass().getSimpleName()));
   }
 
   @Override
@@ -4285,20 +4285,20 @@ public Void visit(CallStatement statement) {
 
   @Override
   public Void visit(PlaceholderStatement statement) {
-    throwUnimplemented(statement);
-    return null;
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(statement.getClass().getSimpleName()));
   }
 
   @Override
   public Void visit(MacroInstanceStatement statement) {
-    throwUnimplemented(statement);
-    return null;
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(statement.getClass().getSimpleName()));
   }
 
   @Override
   public Void visit(MacroMatchStatement statement) {
-    throwUnimplemented(statement);
-    return null;
+    throw new IllegalStateException(
+        "No %s should ever reach the Typechecker".formatted(statement.getClass().getSimpleName()));
   }
 
   @Override