diff --git a/org.lflang.tests/src/org/lflang/tests/compiler/LinguaFrancaValidationTest.java b/org.lflang.tests/src/org/lflang/tests/compiler/LinguaFrancaValidationTest.java
index e493d5a67b..3e5cc075d2 100644
--- a/org.lflang.tests/src/org/lflang/tests/compiler/LinguaFrancaValidationTest.java
+++ b/org.lflang.tests/src/org/lflang/tests/compiler/LinguaFrancaValidationTest.java
@@ -1596,11 +1596,11 @@ private List<String> synthesizeExamples(TargetPropertyType type, boolean correct
             return examples;
         } else {
             if (type instanceof UnionType) {
-                return synthesizeExamples(type, correct);
+                return synthesizeExamples((UnionType) type, correct);
             } else if (type instanceof ArrayType) {
-                return synthesizeExamples(type, correct);
+                return synthesizeExamples((ArrayType) type, correct);
             } else if (type instanceof DictionaryType) {
-                return synthesizeExamples(type, correct);
+                return synthesizeExamples((DictionaryType) type, correct);
             } else {
                 Assertions.fail("Encountered an unknown type: " + type);
             }