I'm lost in generic expect/actual common: ```expect class WeakReference<T>(instance: T) { ...

# multiplatform

[msink]

I'm lost in generic expect/actual
common:

expect class WeakReference<T>(instance: T) {
    fun get(): T?
}

jvm:

actual typealias WeakReference<T> = java.lang.ref.WeakReference<T>

native:

actual typealias WeakReference<T> = kotlin.native.ref.WeakReference<T>

jvm works, native fails with message
"The following declaration is incompatible because upper bounds of type parameters are different:
public actual typealias WeakReference<T> = WeakReference<T>"
What it wants?

[msink]

Well, if common chenged to

expect class WeakReference<T : Any>(referred: T) {
    fun get(): T?
}

it works with native, but fails with jvm.
And really common is not my code, it's part of Jetpack Compose Runtime.

[JoakimForslund]

In my case, I did WeakReference by type by creating another typealias for your generic as "Context"

and then on each platform tell what the Context should be, which in turn can be a generic. Not really sure if it fits your specific usecase tho

[JoakimForslund]

so essentially: WeakReference<Context>
typealias Context<T> = ...

[Thomas]

This is what I am using in my project. I do have the new type inference enabled so maybe that makes the difference?

Common:

expect class WeakReference<T : Any>(referred: T) {

    fun clear()

    fun get(): T?
}

JVM:

actual typealias WeakReference<T> = java.lang.ref.WeakReference<T>

Native:

actual typealias WeakReference<T> = kotlin.native.ref.WeakReference<T>