diff --git a/src/main/java/org/rumbledb/compiler/CloneVisitor.java b/src/main/java/org/rumbledb/compiler/CloneVisitor.java
index 546af9628..d308ed910 100644
--- a/src/main/java/org/rumbledb/compiler/CloneVisitor.java
+++ b/src/main/java/org/rumbledb/compiler/CloneVisitor.java
@@ -448,7 +448,7 @@ public Node visitInlineFunctionExpr(InlineFunctionExpression expression, Node ar
                 expression.getAnnotations(),
                 expression.getName(),
                 expression.getParams(),
-                expression.getReturnType(),
+                expression.getActualReturnType(),
                 (StatementsAndOptionalExpr) visit(expression.getBody(), argument),
                 expression.getMetadata()
         );
diff --git a/src/main/java/org/rumbledb/compiler/ExpressionClassificationVisitor.java b/src/main/java/org/rumbledb/compiler/ExpressionClassificationVisitor.java
index 946772fb2..b585665fa 100644
--- a/src/main/java/org/rumbledb/compiler/ExpressionClassificationVisitor.java
+++ b/src/main/java/org/rumbledb/compiler/ExpressionClassificationVisitor.java
@@ -375,8 +375,11 @@ public ExpressionClassification visitInlineFunctionExpr(
 
         if (expression.isUpdating()) {
             if (expression.getActualReturnType() != null) {
+                System.err.println(expression);
                 throw new UpdatingFunctionHasReturnTypeException(
-                        "An updating function cannot have a return type",
+                        "An updating function cannot have a return type. Return type "
+                            + expression.getActualReturnType()
+                            + " is specified.",
                         expression.getMetadata()
                 );
             }
diff --git a/src/main/java/org/rumbledb/compiler/VisitorHelpers.java b/src/main/java/org/rumbledb/compiler/VisitorHelpers.java
index 691fb1318..7c78ec877 100644
--- a/src/main/java/org/rumbledb/compiler/VisitorHelpers.java
+++ b/src/main/java/org/rumbledb/compiler/VisitorHelpers.java
@@ -154,17 +154,77 @@ public static MainModule parseJSONiqMainModule(
             if (main == null) {
                 throw new ParsingException("A library module is not executable.", ExceptionMetadata.EMPTY_METADATA);
             }
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("***************");
+                System.err.println("Parsing program");
+                System.err.println("***************");
+            }
             MainModule mainModule = (MainModule) visitor.visit(main);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("***************");
+                System.err.println("Pruning modules");
+                System.err.println("***************");
+            }
             pruneModules(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("**********************");
+                System.err.println("Resolving dependencies");
+                System.err.println("**********************");
+            }
             resolveDependencies(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("*************************************");
+                System.err.println("Populating sequential classifications");
+                System.err.println("*************************************");
+            }
             populateSequentialClassifications(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("***************************************");
+                System.err.println("Applying type independent optimizations");
+                System.err.println("***************************************");
+            }
             mainModule = applyTypeIndependentOptimizations(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("*************************");
+                System.err.println("Populating static context");
+                System.err.println("*************************");
+            }
             populateStaticContext(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("*************************************");
+                System.err.println("Populating expression classifications");
+                System.err.println("*************************************");
+            }
             populateExpressionClassifications(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("**************");
+                System.err.println("Infering types");
+                System.err.println("**************");
+            }
             inferTypes(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("************************");
+                System.err.println("Applying type dependent optimizations");
+                System.err.println("************************");
+            }
             mainModule = applyTypeDependentOptimizations(mainModule);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("***************************************");
+                System.err.println("Populating execution modes");
+                System.err.println("***************************************");
+            }
             populateExecutionModes(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("*************************************");
+                System.err.println("Populating expression classifications");
+                System.err.println("*************************************");
+            }
             populateExpressionClassifications(mainModule, configuration);
+            if (configuration.isPrintIteratorTree()) {
+                System.err.println("********************************");
+                System.err.println("Verify composability constraints");
+                System.err.println("********************************");
+            }
             verifyComposabilityConstraints(mainModule, configuration);
             return mainModule;
         } catch (ParseCancellationException ex) {