From 98de9de2816295fec775d3bc0ef9f279d6356a17 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 27 Aug 2015 15:59:00 -0700
Subject: [PATCH] No deduplication in union of tuple element types

---
 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 d9a36c34cdf..43856b535e2 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3119,7 +3119,7 @@ namespace ts {
         }
 
         function resolveTupleTypeMembers(type: TupleType) {
-            let arrayType = resolveStructuredTypeMembers(createArrayType(getUnionType(type.elementTypes)));
+            let arrayType = resolveStructuredTypeMembers(createArrayType(getUnionType(type.elementTypes, /*noDeduplication*/ true)));
             let members = createTupleTypeMemberSymbols(type.elementTypes);
             addInheritedMembers(members, arrayType.properties);
             setObjectTypeMembers(type, members, arrayType.callSignatures, arrayType.constructSignatures, arrayType.stringIndexType, arrayType.numberIndexType);