From b43f717f6d24a6ccbc4152dba8760098a32f7ef1 Mon Sep 17 00:00:00 2001
From: Denis Zharkov <denis.zharkov@jetbrains.com>
Date: Mon, 3 Jun 2019 19:57:44 +0300
Subject: [PATCH] Optimize AbstractTypeChecker::hasNothingSupertype

It doesn't make sense to go through all supertypes because
Nothing is a final class
---
 .../org/jetbrains/kotlin/types/AbstractTypeChecker.kt    | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt b/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
index cb31e57ea16..5a6ffc07839 100644
--- a/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
+++ b/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
@@ -215,14 +215,19 @@ object AbstractTypeChecker {
         return null
     }
 
-    private fun AbstractTypeCheckerContext.hasNothingSupertype(type: SimpleTypeMarker) = // todo add tests
-        anySupertype(type, { it.typeConstructor().isNothingConstructor() }) {
+    private fun AbstractTypeCheckerContext.hasNothingSupertype(type: SimpleTypeMarker): Boolean {
+        val typeConstructor = type.typeConstructor()
+        if (typeConstructor.isClassTypeConstructor()) {
+            return typeConstructor.isNothingConstructor()
+        }
+        return anySupertype(type, { it.typeConstructor().isNothingConstructor() }) {
             if (it.isClassType()) {
                 SupertypesPolicy.None
             } else {
                 SupertypesPolicy.LowerIfFlexible
             }
         }
+    }
 
     private fun AbstractTypeCheckerContext.isSubtypeOfForSingleClassifierType(subType: SimpleTypeMarker, superType: SimpleTypeMarker): Boolean {
         if (AbstractTypeChecker.RUN_SLOW_ASSERTIONS) {