From dd6365615dfe65548578d7ac0d8d92d3f78f7414 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 11 Oct 2018 08:45:47 -0700
Subject: [PATCH] Address CR feedback

---
 src/compiler/checker.ts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 33d23bd11e..c2e8645518 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -9312,12 +9312,11 @@ namespace ts {
                         propType;
                 }
                 if (everyType(objectType, isTupleType) && isNumericLiteralName(propName) && +propName >= 0) {
-                    const restType = mapType(objectType, t => getRestTypeOfTupleType(<TupleTypeReference>t) || undefinedType);
-                    if (restType === undefinedType && accessNode) {
+                    if (accessNode && everyType(objectType, t => !(<TupleTypeReference>t).target.hasRestElement)) {
                         const indexNode = accessNode.kind === SyntaxKind.ElementAccessExpression ? accessNode.argumentExpression : accessNode.indexType;
                         error(indexNode, Diagnostics.Property_0_does_not_exist_on_type_1, unescapeLeadingUnderscores(propName), typeToString(objectType));
                     }
-                    return restType;
+                    return mapType(objectType, t => getRestTypeOfTupleType(<TupleTypeReference>t) || undefinedType);
                 }
             }
             if (!(indexType.flags & TypeFlags.Nullable) && isTypeAssignableToKind(indexType, TypeFlags.StringLike | TypeFlags.NumberLike | TypeFlags.ESSymbolLike)) {