From b66b7525617ecb1bd5b70944224e6b80db7bf772 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Fri, 18 Aug 2017 11:15:42 -0700
Subject: [PATCH] Update based on feedback

---
 src/compiler/core.ts                         | 2 +-
 src/compiler/sys.ts                          | 3 +++
 src/harness/unittests/programMissingFiles.ts | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 1eab3582cb9..e1193d7f71b 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -2736,7 +2736,7 @@ namespace ts {
         function fileExists(fileName: string): boolean {
             const path = toPath(fileName);
             const result = getCachedFileSystemEntriesForBaseDir(path);
-            return (result && hasEntry(result.files, getBaseNameOfFileName(fileName))) ||
+            return result && hasEntry(result.files, getBaseNameOfFileName(fileName)) ||
                 host.fileExists(fileName);
         }
 
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index aafb97f4131..982d6793819 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -30,6 +30,9 @@ namespace ts {
         mtime?: Date;
     }
 
+    /**
+     * Partial interface of the System thats needed to support the caching of directory structure
+     */
     export interface PartialSystem {
         writeFile(path: string, data: string, writeByteOrderMark?: boolean): void;
         fileExists(path: string): boolean;
diff --git a/src/harness/unittests/programMissingFiles.ts b/src/harness/unittests/programMissingFiles.ts
index 20323b37380..ce8abc232e7 100644
--- a/src/harness/unittests/programMissingFiles.ts
+++ b/src/harness/unittests/programMissingFiles.ts
@@ -3,7 +3,7 @@
 namespace ts {
     function verifyMissingFilePaths(missingPaths: ReadonlyArray<Path>, expected: ReadonlyArray<string>) {
         assert.isDefined(missingPaths);
-        const map = arrayToMap(expected, k => k, _v => true);
+        const map = arrayToSet(expected) as Map<boolean>;
         for (const missing of missingPaths) {
             const value = map.get(missing);
             assert.isTrue(value, `${missing} to be ${value === undefined ? "not present" : "present only once"}, in actual: ${missingPaths} expected: ${expected}`);