diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index f26170ef6a..980a27446f 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -164,7 +164,7 @@ namespace ts.projectSystem {
     }
 
     export function fileStats(nonZeroStats: Partial<server.FileStats>): server.FileStats {
-        return { ts: 0, tsx: 0, dts: 0, js: 0, jsx: 0, ...nonZeroStats };
+        return { ts: 0, tsx: 0, dts: 0, js: 0, jsx: 0, deferred: 0, ...nonZeroStats };
     }
 
     export class TestServerEventManager {
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 061ff2aeae..c069dbf4d0 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -8047,6 +8047,7 @@ declare namespace ts.server {
         readonly ts: number;
         readonly tsx: number;
         readonly dts: number;
+        readonly deferred: number;
     }
     interface OpenFileInfo {
         readonly checkJs: boolean;