diff --git a/src/common/services/InstantiationService.ts b/src/common/services/InstantiationService.ts
index 375e442def..7e76954856 100644
--- a/src/common/services/InstantiationService.ts
+++ b/src/common/services/InstantiationService.ts
@@ -67,7 +67,7 @@ export class InstantiationService implements IInstantiationService {
     for (const dependency of serviceDependencies) {
       const service = this._services.get(dependency.id);
       if (!service) {
-        throw new Error(`[createInstance] ${ctor.name} depends on UNKNOWN service ${dependency.id}.`);
+        throw new Error(`[createInstance] ${ctor.name} depends on UNKNOWN service ${dependency.id._id}.`);
       }
       serviceArgs.push(service);
     }
diff --git a/src/common/services/ServiceRegistry.ts b/src/common/services/ServiceRegistry.ts
index 6510fb8e04..7d887bc612 100644
--- a/src/common/services/ServiceRegistry.ts
+++ b/src/common/services/ServiceRegistry.ts
@@ -33,7 +33,7 @@ export function createDecorator<T>(id: string): IServiceIdentifier<T> {
     storeServiceDependency(decorator, target, index);
   };
 
-  decorator.toString = () => id;
+  decorator._id = id;
 
   serviceRegistry.set(id, decorator);
   return decorator;
diff --git a/src/common/services/Services.ts b/src/common/services/Services.ts
index 0e5c518484..be1dec064a 100644
--- a/src/common/services/Services.ts
+++ b/src/common/services/Services.ts
@@ -124,6 +124,7 @@ export interface ICharsetService {
 export interface IServiceIdentifier<T> {
   (...args: any[]): void;
   type: T;
+  _id: string;
 }
 
 export interface IBrandedService {