If I have: ```@JvmInline value class Incomplete<T>...

# getting-started

[dave08]

If I have:

@JvmInline
value class Incomplete<T>(private val value: T) {
....
    // this won't compile
    fun filterNotNull(): Incomplete<T & Any>? =
        if (value != null) this else null
...
}

I don't want T on the class to inherit Any, since it can be null but I want the instance returned to not be nullable... could this solve the problem (is there a better way?)?

@Suppress("UNCHECKED_CAST")
    fun <R : T & Any> filterNotNull(): Incomplete<R>? =
        if (value != null) this as Incomplete<R> else null

(this forces me to specify the type at the call site...)

[ephemient]

it works without any extra type parameter R as an extension

class Incomplete<out T>(private val value: T)
fun <T: Any> Incomplete<T?>.filterNotNull(): Incomplete<T>?

which is what stdlib does

[dave08]

Then I don't have access to the private value...

[dave08]

fun <T: Any> Incomplete<T?>.filterNotNull(): Incomplete<T>? =
    if (value != null) this as Incomplete<T> else null

imports

import sun.jvm.hotspot.oops.CellTypeState.value

instead of using the value class's value @ephemient

[Youssef Shoaib [MOD]]

You could write it in the companion object which will give you access to the private one I believe

[dave08]

Thanks! And Intellij seems to import that automatically...

[ephemient]

or use @PublishedApi internal

[dave08]

Yeah, I'd have to maybe separate this into a different gradle module or library for that... but it might be better in the end. But why do I need the PublishedApi annotation?

[ephemient]

@JvmInline
value class Incomplete<out T>(@PublishedApi private val value: T)

allows

inline fun <T: Any> Incomplete<T?>.filterNotNull(): Incomplete<T>? = if (value != null) Incomplete(value) else null

to access internal value within the same module

[dave08]

You mean

@JvmInline
value class Incomplete<out T>(@PublishedApi >>>internal<<< val value: T)

[dave08]

Or does it work for private too?

[dave08]

Also, I thought internal by itself already allows that access?

[ephemient]

ah I meant internal

[ephemient]

internal by itself allows that access for non-inline functions, @PublishedApi is necessary for inline functions because they get inlined into other modules