diff --git a/java/ql/lib/semmle/code/java/KotlinType.qll b/java/ql/lib/semmle/code/java/KotlinType.qll
index 3122e124d9c..a4c07007cbf 100755
--- a/java/ql/lib/semmle/code/java/KotlinType.qll
+++ b/java/ql/lib/semmle/code/java/KotlinType.qll
@@ -9,18 +9,18 @@ class KotlinType extends Element, @kt_type {
 
 class KotlinNullableType extends KotlinType, @kt_nullable_type {
   override string toString() {
-    exists(ClassOrInterface ci |
-           kt_nullable_types(this, ci) and
-           result = "Kotlin nullable " + ci.toString())
+    exists(RefType javaType |
+           kt_nullable_types(this, javaType) and
+           result = "Kotlin nullable " + javaType.toString())
   }
   override string getAPrimaryQlClass() { result = "KotlinNullableType" }
 }
 
 class KotlinNotnullType extends KotlinType, @kt_notnull_type {
   override string toString() {
-    exists(ClassOrInterface ci |
-           kt_notnull_types(this, ci) and
-           result = "Kotlin not-null " + ci.toString())
+    exists(RefType javaType |
+           kt_notnull_types(this, javaType) and
+           result = "Kotlin not-null " + javaType.toString())
   }
   override string getAPrimaryQlClass() { result = "KotlinNotnullType" }
 }