From 672d2144fa8ff41612e2cce196ce0f85701c337a Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 30 Apr 2018 10:43:43 -0700
Subject: [PATCH] Check for null type instead of null keyword

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index ae59997b7a2..9bd940e547e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -13690,7 +13690,7 @@ namespace ts {
                     const doubleEquals = operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.ExclamationEqualsToken;
                     const facts = doubleEquals ?
                         assumeTrue ? TypeFacts.EQUndefinedOrNull : TypeFacts.NEUndefinedOrNull :
-                        value.kind === SyntaxKind.NullKeyword ?
+                        valueType.flags & TypeFlags.Null ?
                             assumeTrue ? TypeFacts.EQNull : TypeFacts.NENull :
                             assumeTrue ? TypeFacts.EQUndefined : TypeFacts.NEUndefined;
                     return getTypeWithFacts(type, facts);