Hello everyone, I tried the reified feature of Kotlin and was suprised, that my primitives becomes boxed. Wouldn't it make sense with inlined reified functions to have monomorphization as language feature? Here's a little example:

fun main() {
    val value: Int = 2
    showValue<Int>(value)
}

inline fun <reified T> showValue(value: T) = println("$value")

The decompiled Java shows that the primitive int will be boxed into an Integer. And the function-signature has an Object as parameter-type. I think, although the reified function will be inlined, that the use of primitives, or whatever object for T, stays the same, because of inlining. Is this possible? Thank you

it would make sense, but difficult. currently inlining is done by copy-paste of bytecode from the inline function - which is only compiled once - into each caller. replacing a generic boxed type doesn't require changing any bytecode instructions, just some references. but (at least on JVM) primitives use a completely different set of instructions

Thank you very much for the answer. I will try the flag and see how things go

Generally Kotlin has some optimizations that eliminate unnecessary boxing-unboxing pairs during inlining even when the inline function is not reified. I suggest to file a feature request for this case. https://kotl.in/issue

I suppose if you could teach the optimizer that aload+invokevirtual[Object.toString()] is equivalent to aload+invokevirtual[Integer.intValue()]+invokestatic[Integer.toString(i)] on Integer, then an existing box removal optimization could then replace invokestatic[Integer.valueOf(i)]+astore...aload+invokeVirtual[Integer.intValue()] with istore...iload? seems awfully specific to this case though