ngOnDestroy not called for injectables created via factory providers

[IgorMinar]

Current behavior

export class DestroyTest implements OnDestroy {
  ngOnDestroy() {  // <<<<< this method is NEVER called
    console.log('ngOnDestroy DestroyTest called');
  }
}

export class DestroyTest2 implements OnDestroy {
  ngOnDestroy() { // <<<<< this method IS called when the app ref is being destroyed
    console.log('ngOnDestroy DestroyTest2 called');
  }
}

export function createDestroyTest() {
  return new DestroyTest();
}

@NgModule({
  imports:      [ BrowserModule, FormsModule ],
  declarations: [ AppComponent, HelloComponent ],
  bootstrap:    [ AppComponent ],
  providers: [
    {provide: DestroyTest, useFactory: createDestroyTest},
    DestroyTest2
  ]
})
export class AppModule {
  constructor(
    destroyTest1: DestroyTest, destroyTest2: DestroyTest2) {}
}

Expected behavior

the ngOnDestroy method, if present, should be called on all values provided via DI regardless of the provider type.

Minimal reproduction of the problem with instructions

https://stackblitz.com/edit/angular-h15slp

Environment

Angular version: 6.0.0-beta.x

// Note: reported by GX

[trotyl]

Duplicate of #14818, #22240

[tmair]

There are already bugs within the angular framework, that are caused by this issue (for example the Router is created via a factory function).

The associated bugs contain some comments, that it is currently not possible to do an analysis at compile time if the factory function returns an object that implements the ngOnDestroy hook and that currently this works as intended.

[swicken]

We are encountering what appears to be this issue in our application as well. Any route changes with routerLink or router.navigate, ngOnDestroy is not called and the component becomes detached in memory. This is causing a pretty severe memory leak.

Does anyone have any workarounds for this?