diff --git a/src/main/ts/di/Annotations.ts b/src/main/ts/di/Annotations.ts
--- a/src/main/ts/di/Annotations.ts
+++ b/src/main/ts/di/Annotations.ts
@@ -19,7 +19,7 @@ type VisitDependency<D, S> = D extends {
 export class Builder<T, S> {
     consume<P extends any[]>(...args: P) {
         return <C extends new (...args: ExtractDependency<P, S>) => T>(constructor: C) => {
-            // return constructor;
+            return constructor as typeof constructor & { service: () => T };
         };
     }
 
@@ -34,4 +34,8 @@ export class Builder<T, S> {
         };
     }
 
+    cast<T2 extends T>(): Builder<T2, S> {
+        return this as Builder<T2, S>;
+    }
+
 }
diff --git a/src/test/ts/mock/Box.ts b/src/test/ts/mock/Box.ts
--- a/src/test/ts/mock/Box.ts
+++ b/src/test/ts/mock/Box.ts
@@ -25,4 +25,4 @@ export class Box<T> {
 
         return this._value;
     }
-}
+}
\ No newline at end of file
diff --git a/src/test/ts/mock/config.ts b/src/test/ts/mock/config.ts
--- a/src/test/ts/mock/config.ts
+++ b/src/test/ts/mock/config.ts
@@ -61,7 +61,8 @@ const t = {
     timeout: Number
 };
 
+declare const bc: typeof Box;
+
+const x = new bc();
+
 export declare const config: ConfigBuilder<ContainerServices>;
-config
-    .mapTo("bar", )
-    .mapTo("barBox", ;