From bb1c91fac6945481e0a56cebce98b855482377e4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 17 Jan 2019 17:04:29 -0800
Subject: [PATCH] Remove literal freshness when contextual type is a literal
 type

---
 src/compiler/checker.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 352a5c31592..f66667d2ddc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -22962,7 +22962,9 @@ namespace ts {
             context.contextualMapper = contextualMapper;
             const checkMode = contextualMapper === identityMapper ? CheckMode.SkipContextSensitive :
                 contextualMapper ? CheckMode.Inferential : CheckMode.Contextual;
-            const result = checkExpression(node, checkMode);
+            const type = checkExpression(node, checkMode);
+            const result = maybeTypeOfKind(type, TypeFlags.Literal) && isLiteralOfContextualType(type, instantiateContextualType(contextualType, node)) ?
+                getRegularTypeOfLiteralType(type) : type;
             context.contextualType = saveContextualType;
             context.contextualMapper = saveContextualMapper;
             return result;