diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index ccc56a6d314..bce4c9828fa 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -336,8 +336,8 @@ module Harness.LanguageService {
         getOccurrencesAtPosition(fileName: string, position: number): ts.ReferenceEntry[] {
             return unwrapJSONCallResult(this.shim.getOccurrencesAtPosition(fileName, position));
         }
-        getDocumentHighlights(fileName: string, position: number): ts.DocumentHighlights[] {
-            return unwrapJSONCallResult(this.shim.getDocumentHighlights(fileName, position));
+        getDocumentHighlights(fileName: string, position: number, filesToSearch: string[]): ts.DocumentHighlights[] {
+            return unwrapJSONCallResult(this.shim.getDocumentHighlights(fileName, position, JSON.stringify(filesToSearch)));
         }
         getNavigateToItems(searchValue: string): ts.NavigateToItem[] {
             return unwrapJSONCallResult(this.shim.getNavigateToItems(searchValue));