Can I get a KFunction from a variable of function type in Kotlin?

Question

I'm trying to get the name that a function was defined with

fun aFunction() = Unit

fun functionName(function: () -> Unit) : String {
  val functionAsKFunction: KFunction<Unit> = someMiracle(function)
  return functionAsKFunction.name
}

assertEquals("aFunction", functionName(::aFunction)) 

Answer 1

You can simply cast () -> Unit to KFunction<*>. Theoretically, this is an implementation detail, but I don't think it will ever break.

fun functionName(function: () -> Unit) : String {
  val functionAsKFunction: KFunction<*> = function as KFunction<*> 
  return functionAsKFunction.name
}

Edit: Obviously, this won't work for lambdas (what name would you expect anyway?) To prevent crashes, you can use a safe cast like so:

fun functionName(function: () -> Unit) : String? {
  val functionAsKFunction: KFunction<*> = function as? KFunction<*> ?: return null
  return functionAsKFunction.name
}