DummyBuilder.kt

@Module
abstract class DummyBuilder {
    @ContributesAndroidInjector(modules = [DummyModule::class])
    abstract fun bindDummygFragment(): DummyFragment

    // put binding of fragment at this layer(not DummyModule) for parent to inject
    @Binds
    @IntoMap
    @FragmentKey(DummyFragment::class)
    abstract fun bindDummyFragment(fragment: DummyFragment): Fragment
}