diff --git a/src/server/utilities.ts b/src/server/utilities.ts
index a086d95f910..2b38de6fa55 100644
--- a/src/server/utilities.ts
+++ b/src/server/utilities.ts
@@ -83,7 +83,7 @@ namespace ts.server {
         };
     }
 
-    export function mergeMapLikes(target: MapLike<any>, source: MapLike<any>): void {
+    export function mergeMapLikes<T extends object>(target: T, source: Partial<T>): void {
         for (const key in source) {
             if (hasProperty(source, key)) {
                 target[key] = source[key];
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 43ebec6ad24..c04a26b117c 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -4966,7 +4966,7 @@ declare namespace ts.server {
         function ThrowProjectDoesNotContainDocument(fileName: string, project: Project): never;
     }
     function getDefaultFormatCodeSettings(host: ServerHost): FormatCodeSettings;
-    function mergeMapLikes(target: MapLike<any>, source: MapLike<any>): void;
+    function mergeMapLikes<T extends object>(target: T, source: Partial<T>): void;
     type NormalizedPath = string & {
         __normalizedPathTag: any;
     };