HiltViewModel: Cannot create an instance of class

Issue

I am using Hilt. After updating to 1.0.0-alpha03 I got warnings that @ViewModelInject is deprecated and I should use @HiltViewModel. But when I change it I got an error:

java.lang.RuntimeException: Cannot create an instance of class com.example.LoginViewModel
...
Caused by: java.lang.NoSuchMethodException: com.example.LoginViewModel.<init> [class android.app.Application]

Previous my ViewModel looked like this:

class LoginViewModel @ViewModelInject constructor(
    application: Application,
    private val repository: RealtimeDatabaseRepository
) : AndroidViewModel(application)

Now it looks like this:

@HiltViewModel
class LoginViewModel @Inject constructor(
    application: Application,
    private val repository: RealtimeDatabaseRepository
) : AndroidViewModel(application)

Fragment where ViewModel is injected:

@AndroidEntryPoint
class LoginFragment : Fragment(R.layout.fragment_login)
{
    private val viewModel: LoginViewModel by activityViewModels()
}

Injected class:

@Singleton
class RealtimeDatabaseRepository @Inject constructor() { }

When I deleted private val repository: RealtimeDatabaseRepository from ViewModel constructor it is working

---

I was using hilt version 2.30.1-alpha when I updated to 2.31.2-alpha, as USMAN osman suggested, the error is gone.

Solution

With new hilt version lots of stuff has been changed.
You also have to upgrade your hilt android, hilt compiler and hilt gradle plugin to:2.31-alpha
I made mock sample exactly the way you did i had same issue, after going through hilt's docs i found new way to inject dependencies to viewModels, you have to make separate module for dependencies which are going to inject in the viewModel with special component called ViewModelComponent:

@Module
@InstallIn(ViewModelComponent::class) // this is new
object RepositoryModule{

    @Provides
    @ViewModelScoped // this is new
    fun providesRepo(): ReposiotryIMPL { // this is just fake repository
        return ReposiotryIMPL()
    }

}

here is what docs says about ViewModelComponent and ViewModelScoped

All Hilt View Models are provided by the ViewModelComponent which follows the same lifecycle as a ViewModel, i.e. it survives configuration changes. To scope a dependency to a ViewModel use the @ViewModelScoped annotation.

A @ViewModelScoped type will make it so that a single instance of the scoped type is provided across all dependencies injected into the Hilt View Model.
link: https://dagger.dev/hilt/view-model.html

then your viewModel:

@HiltViewModel
class RepoViewModel @Inject constructor(
    application: Application,
    private val reposiotryIMPL: ReposiotryIMPL
) : AndroidViewModel(application) {}

UPDATE
It is not mandatory that you should be using ViewModelComponent or ViewModelScoped as i did in the above example. You can also use other scopes or components depends on your usecase.
Furthermore read docs, i put the dagger-hilt's link above.

Answered By - USMAN osman