Type parameter problem with Nullable and Not-Nullable

1

hi, the following code shows no error in IDE. 


fun <X:Any,T:X?> T.ifNotNull(f:(x:X)->Unit):T{
    if(this!=null) {
        f(this)   // not null !
    }
    return this
}



val items : MutableList<CartItem> …

…

ShoppingCart load product.code ifNotNull {

  items add it

}

But the compiler throws :

Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
internal fun <X : jet.Any, T : X?> T.ifNotNull(f: (X) -> jet.Unit): T defined in name.my.store.service

Why?

For now I have to change back to this version :

fun <T> T.ifNotNull(f:(x:T)->Unit):T{
    if(this!=null) {
        f(this)   // still nullable
    }
    return this
}




ShoppingCart load product.code ifNotNull {
    items add it!!   // !! is needed here.
}

is this a bug ?

BTW: I’m using  kotlin-compiler-0.1-20130802.155613-19.jar

Thanks.

Outersky

2

OK, I'm such a idiot , this works:

``

fun <T:Any> T?.ifNotNull(f:(x:T)->Unit):T?{

  if(this!=null) {

  f(this)

  }

  return this

}

3

Nevertheless your first example is a bug. I've created an issue about it (http://youtrack.jetbrains.com/issue/KT-3850).