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is there a trick to implementing preincrement for an inline class wrapping an int?  post-increment is working fine for me but preincrement isn't

Can you provide an example of your issue? You don't implement pre vs post, you just implement `inc` and whether it's pre or post depends on how you use it.

yeah that's what i thought, but i get different behaviors for each.  let me see if i can slim down an example

```inline class WrappingInt(val value: Int) {
    operator fun inc(): WrappingInt = plus(1)
    operator fun plus(num: Int): WrappingInt = WrappingInt((value + num) and 0xFFFF)
}

fun main() {
    var x = WrappingInt(65535)
    x++
    println(x) // prints 0 (correct)

    var y = WrappingInt(65535)
    ++y
    println(y) // prints 65536
}```

Interesting, and removing the `inline` fixes it. I think you've found a bug. You should report it at <http://kotl.in/issue|kotl.in/issue> (and link it back here)

<https://youtrack.jetbrains.com/issue/KT-33119?project=kt>

Ah, it looks like the prefix is being compiled directly to `IINC` whereas the postfix is correctly compiled to `INVOKESTATIC WrappingInt.inc-impl`. Good catch.

something like this does seem to work: ```var z = WrappingInt(65535)
    val zz = { -&gt;
        ++z
        println(z)
    }```

i guess it's triggering some boxing maybe?

i had unit tests for pre-increment and they actually work inside a kotlintest `should` block for this reason, i think, so this was a sneaky one :confused: