Store the DI decorator's id in specific property (#5131).

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);
     }

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;

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 {