From cdda5dfd61fd0b3a7288619895ec3f85ebec1c70 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Wed, 23 Nov 2016 18:22:57 -0800
Subject: [PATCH] keyof T is a literal contextual type

---
 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 6d5a8b74cb3..f0c6e4edb42 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14870,7 +14870,7 @@ namespace ts {
                     }
                     contextualType = apparentType;
                 }
-                return maybeTypeOfKind(contextualType, TypeFlags.Literal);
+                return maybeTypeOfKind(contextualType, (TypeFlags.Literal | TypeFlags.Index));
             }
             return false;
         }