From 88349ab436117ce31829afefda42cd049fd64d7b Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 12 Sep 2016 12:41:15 -0700
Subject: [PATCH] Quick bail out when narrowing type any by equality

---
 src/compiler/checker.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 8dca2ac0d0b..7199e4a548f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8522,6 +8522,9 @@ namespace ts {
             }
 
             function narrowTypeByEquality(type: Type, operator: SyntaxKind, value: Expression, assumeTrue: boolean): Type {
+                if (type.flags & TypeFlags.Any) {
+                    return type;
+                }
                 if (operator === SyntaxKind.ExclamationEqualsToken || operator === SyntaxKind.ExclamationEqualsEqualsToken) {
                     assumeTrue = !assumeTrue;
                 }