diff --git a/packages/di/src/inject.ts b/packages/di/src/inject.ts
index a7468261c7..9046a9faee 100644
--- a/packages/di/src/inject.ts
+++ b/packages/di/src/inject.ts
@@ -20,7 +20,7 @@ export function Inject(dependency?: ServiceIdentifier<any>) {
   };
 }
 export function InjectFunction<Dependencies extends Array<ServiceIdentifier<any>>, Fn extends (...args: Instances<Dependencies>) => any>(...dependencies: Dependencies) {
-  return (target: Fn): (...args: any[]) => ReturnType<Fn> => {
+  return (target: Fn): any => {
     Reflect.defineMetadata(DESIGN_PARAM_TYPES, dependencies, target);
     return target;
   };
diff --git a/packages/di/tsconfig.json b/packages/di/tsconfig.json
index a5eca15925..066bca9096 100644
--- a/packages/di/tsconfig.json
+++ b/packages/di/tsconfig.json
@@ -21,7 +21,8 @@
     "noImplicitReturns": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
-    "downlevelIteration": true
+    "downlevelIteration": true,
+    "strictFunctionTypes": true
   },
   "files": ["src/index.ts"],
   "exclude": ["node_modules"]