From 398d3aaf6cae5026416550608e9adb4fcdaa01ab Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Thu, 4 May 2017 12:45:15 -0700
Subject: [PATCH] Symbol table for homomorphic mapped type: Don't needlessly
 create twice

---
 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 e1ed2f4fa1f..ec88d88c3ad 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10022,7 +10022,7 @@ namespace ts {
             const templateType = getTemplateTypeFromMappedType(target);
             const readonlyMask = target.declaration.readonlyToken ? false : true;
             const optionalMask = target.declaration.questionToken ? 0 : SymbolFlags.Optional;
-            const members = createSymbolTable(properties);
+            const members = createMap<Symbol>();
             for (const prop of properties) {
                 const inferredPropType = inferTargetType(getTypeOfSymbol(prop));
                 if (!inferredPropType) {