diff --git a/compiler/light-classes/src/org/jetbrains/kotlin/asJava/duplicateJvmSignatureUtil.kt b/compiler/light-classes/src/org/jetbrains/kotlin/asJava/duplicateJvmSignatureUtil.kt
index f7c229e7d0e..6007b930cb3 100644
--- a/compiler/light-classes/src/org/jetbrains/kotlin/asJava/duplicateJvmSignatureUtil.kt
+++ b/compiler/light-classes/src/org/jetbrains/kotlin/asJava/duplicateJvmSignatureUtil.kt
@@ -51,7 +51,7 @@ fun getJvmSignatureDiagnostics(element: PsiElement, otherDiagnostics: Diagnostic
 
     fun doGetDiagnostics(): Diagnostics? {
         //TODO: enable this diagnostic when light classes for scripts are ready
-        if ((element.containingFile as? KtFile)?.isScript() ?: false) return null
+        if ((element.containingFile as? KtFile)?.isScript() == true) return null
 
         var parent = element.parent
         if (element is KtPropertyAccessor) {