Generated Java code doesn't compile with Kotlin

I’m using AssistedInject library to generate factories. Build fails when I map factory interface to its generated implementation via @Binds in a @Module. How can I make it work? ViewModel:

class FeedDetailsViewModel @AssistedInject constructor(
    @Assisted private val feedId: FeedId,
    private val getFeedUseCase: GetFeedUseCase
) : BaseViewModel() {
    ...
    @AssistedInject.Factory
    interface Factory {
        fun create(feedId: FeedId): FeedDetailsViewModel
    }
}

Generated factory:

public final class FeedDetailsViewModel_AssistedFactory implements FeedDetailsViewModel.Factory {
  private final Provider<GetFeedUseCase> getFeedUseCase;

  @Inject
  public FeedDetailsViewModel_AssistedFactory(Provider<GetFeedUseCase> getFeedUseCase) {
    this.getFeedUseCase = getFeedUseCase;
  }

  @Override
  public FeedDetailsViewModel create(FeedId feedId) {
    return new FeedDetailsViewModel(
        feedId,
        getFeedUseCase.get());
  }
}

Module:

@Module
interface FeedDetailsActivityModuleKotlin {
    @Binds
    fun viewModelFactory(factory: FeedDetailsViewModel_AssistedFactory): FeedDetailsViewModel.Factory
}

Build fails with the following error:

e: /app/build/tmp/kapt3/stubs/debug/../FeedDetailsActivityModuleKotlin.java:11: error: @Binds methods must have only one parameter whose type is assignable to the return type
    public abstract com.nikolaykul.sebastian.presentation.feed.details.FeedDetailsViewModel.Factory viewModelFactory(@org.jetbrains.annotations.NotNull()

A few notes:

1. Java version of the same Module builds fine:

@Module
public interface FeedDetailsActivityModuleJava {
    @Binds
    FeedDetailsViewModel.Factory viewModuleFactory(FeedDetailsViewModel_AssistedFactory factory);
}

1. Using @AssistedModule (generated module with all mappings) builds fine as well. I guess thats because it generates java-code:

@Module(includes = [AssistedInject_ViewModelModule::class])
interface ViewModelModule

@Module
public abstract class AssistedInject_ViewModelModule {
  private AssistedInject_ViewModelModule() {
  }

  @Binds
  abstract FeedDetailsViewModel.Factory bind_com_nikolaykul_sebastian_presentation_feed_details_FeedDetailsViewModel(
      FeedDetailsViewModel_AssistedFactory factory);
}

[Chang-Eric]

I think this is probably an issue with needed to set correctErrorTypes in kapt.

kapt {
 correctErrorTypes true
}

Going to close this assuming that is the fix, but can reopen if it doesn’t work.

[nlgtuankiet]

Several line of code will do

class Bar @Inject constructor()

class Foo @AssistedInject constructor(
    @Assisted bar: Bar,
    bar2: Bar
) {
    @AssistedInject.Factory
    interface Factory {
        fun create(bar: Bar): Foo
    }
}

@Module
interface Binding {
    @Binds
    @IntoSet
    fun bind(factory: Foo_AssistedFactory): Foo.Factory
}

@Component(modules = [Binding::class])
interface Component

Source: https://github.com/nlgtuankiet/dagger_kotlin_java_issue Run kaptDebugKotlin