From 835950a674cdbd197d7cdc0d6d158f173c093800 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <t-weswig@microsoft.com>
Date: Fri, 4 Dec 2015 13:44:16 -0800
Subject: [PATCH] check for presence of array

---
 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 d65b202725e..6f10792e54e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1153,7 +1153,7 @@ namespace ts {
                     for (const id in lookupTable) {
                         const { exportsWithDuplicate } = lookupTable[id];
                         // It's not an error if the file with multiple `export *`s with duplicate names exports a member with that name itself
-                        if (id === "export=" || !exportsWithDuplicate.length || hasProperty(symbols, id)) {
+                        if (id === "export=" || !(exportsWithDuplicate && exportsWithDuplicate.length) || hasProperty(symbols, id)) {
                             continue;
                         }
                         for (const node of exportsWithDuplicate) {