Workaround for compiler bug

idea/ide-common/src/org/jetbrains/kotlin/idea/codeInsight/ReferenceVariantsHelper.kt

@@ -108,6 +108,7 @@ public class ReferenceVariantsHelper(
             is CallTypeAndReceiver.SAFE -> receiverExpression = callTypeAndReceiver.receiver
             is CallTypeAndReceiver.INFIX -> receiverExpression = callTypeAndReceiver.receiver
             is CallTypeAndReceiver.UNARY -> receiverExpression = null // can it happen at all?
+            else -> throw RuntimeException() //TODO: see KT-9394
         }
 
         val resolutionScope = resolutionScope(expression) ?: return emptyList()

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt

@@ -341,6 +341,7 @@ abstract class CompletionSession(protected val configuration: CompletionSessionC
             is CallTypeAndReceiver.IMPORT_DIRECTIVE -> receiverExpression = callTypeAndReceiver.receiver
             is CallTypeAndReceiver.PACKAGE_DIRECTIVE -> receiverExpression = callTypeAndReceiver.receiver
             is CallTypeAndReceiver.TYPE -> receiverExpression = callTypeAndReceiver.receiver
+            else -> throw RuntimeException() //TODO: see KT-9394
         }
 
         val receiverValues = if (receiverExpression != null) {