diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index f85f4b443de..d2b389c4373 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -3231,7 +3231,7 @@ Actual: ${stringify(fullActual)}`);
 
                 const availableNames: string[] = [];
                 const result = ts.forEach(this.testData.files, file => {
-                    const fn = file.fileName;
+                    const fn = ts.normalizePath(file.fileName);
                     if (fn) {
                         if (fn === name) {
                             return file;
diff --git a/src/services/services.ts b/src/services/services.ts
index ab359c35323..bceb7f572af 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1673,7 +1673,7 @@ namespace ts {
         }
 
         function getDocumentHighlights(fileName: string, position: number, filesToSearch: ReadonlyArray<string>): DocumentHighlights[] {
-            filesToSearch = ts.map(filesToSearch, ts.normalizePath);
+            filesToSearch = map(filesToSearch, normalizePath);
             Debug.assert(contains(filesToSearch, fileName));
             synchronizeHostData();
             const sourceFilesToSearch = map(filesToSearch, f => Debug.assertDefined(program.getSourceFile(f)));