Is it not possible to save a lambda parameter from a inline function to a variable? This doesn't wo...

# getting-started

[Jan]

Is it not possible to save a lambda parameter from a inline function to a variable?
This doesn't work:

@PublishedApi
internal var onFinish = {}

inline fun onFinish(action: () -> Unit) {
    onFinish = action
}

[Sam]

It's not possible because lambda arguments to inline functions are themselves also inlined:

The inline modifier affects both the function itself and the lambdas passed to it: all of those will be inlined into the call site.

https://kotlinlang.org/docs/inline-functions.html

[Sam]

So at the time when the function is called, the parameter doesn't really exist. There is no lambda function to store a reference to.

[ephemient]

that can be avoided with the noinline keyword, as documented there

[ephemient]

or with

inline fun onFinish(crossinline action: () -> Unit) {
    onFinish = { action() }
}

but that is definitely less clear than noinline

[Jan]

hmm okay thanks