Hello, AndroidViewModel.getApplication() was accepted for boolean parameter, and i have only a runt...

# android

[Gabriel Brollo]

Hello,

AndroidViewModel.getApplication() was accepted for boolean parameter, and i have only a runtime exception.
Is that a problem with generic function? But it should extend a Application class

[radityagumay]

wouldn't that different types?

[Gabriel Brollo]

For me yes, but not for compiler :/

[Nikolay Puliaev]

Are you sure, that it’s ok to call application inside of view model?

[Gabriel Brollo]

AndroidViewModel class holds this getApplication

[Nikolay Puliaev]

Oh, sorry, I’ve missed that it is AndroidViewModel

[StavFX]

As you suspect, this shouldn’t happen, as Boolean doesn’t extend Application.
Is there another override of getMeasures maybe?

[Gabriel Brollo]

No, getMeasures is in a interface and only have one implementation

[StavFX]

Huh, yeah you are right.. weird..

[StavFX]

Distilled to remove any dependencies on Android/ViewModels:

fun main() {
        val b: Boolean = num() // compiles, but shouldn't
        f(num()) // also compiles, but shouldn't
    }

    fun <T : Number> num(): T = 4 as T

    fun f(b: Boolean) = b

The Java equivalent works as expected

void main() {
        final Integer n = num(); // Complies
        final Boolean b = num(); // Does not compile
        f(num()); // Does not compile
    }

    <T extends Number> T num() { return (T) new Integer(4); }

    void f(Boolean b) { }

I guess it’s a Kotlin bug

[Gabriel Brollo]

Yes, maybe a bug in the type inference?

[Gabriel Brollo]

If i move your num method to a class like

class GenericClass<T : Number> {

    fun num() = 4 as T
}

[Gabriel Brollo]

i have to implicitly say the type

[Gabriel Brollo]

val b: Boolean = GenericClass<Boolean>().num()

does not compile

[StavFX]

I would be even more surprised if that also complied

[Gabriel Brollo]

I opened an issue (https://youtrack.jetbrains.com/issue/KT-43541), let's wait to know

[Gabriel Brollo]

Thank you for your help