Is it correct that, currently, we can't create inl...

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[melatonina]

Is it correct that, currently, we can't create inline classes that implement Comparable<T>?

[elizarov]

Why? What kind of error are you getting?

[melatonina]

I'm getting the following exception at runtime:

Caused by: java.lang.ClassCastException: class com.aeyeonmovement.FrameIndex cannot be cast to class java.lang.Number (com.aeyeonmovement.FrameIndex is in unnamed module of loader 'app'; java.lang.Number is in module java.base of loader 'bootstrap')

[melatonina]

Is this the same as https://youtrack.jetbrains.com/issue/KT-36420 ?

[melatonina]

This is a piece of stack trace:

Exception in thread "JavaFX Application Thread @coroutine#15" java.lang.ClassCastException: class com.aeyeonmovement.FrameIndex cannot be cast to class java.lang.Number (com.aeyeonmovement.FrameIndex is in unnamed module of loader 'app'; java.lang.Number is in module java.base of loader 'bootstrap')
	at com.aeyeonmovement.FrameIndex.next-t4yMDwI(FrameIndex.kt:7)
	at com.aeyeonmovement.FrameIndexRange$Iterator.next-t4yMDwI(FrameIndexRange.kt:60)
	at com.aeyeonmovement.FrameIndexRange$Iterator.next(FrameIndexRange.kt:55)

[melatonina]

Ok. It does not seem to be related to the Comparable interface. It happens, when the method next() is called. FrameIndex implements Index<FrameIndex> which is defined as:

interface Index<T> : Comparable<T> {
    val value : Int

    val number get() = value + 1

    val isStrictlyNegative get() =
        value < 0
    val isPositive get() =
        value >= 0

    val isOdd: Boolean get() = value % 2 != 0

    operator fun plus(n : Int) : T
    operator fun minus(n : Int) : T

    fun next() : T = this + 1
    fun previous() : T = this - 1

    val parity get() = Parity.of(value)
}

That next() method is the one that is called.

[melatonina]

I still don't understand why FrameIndex needs to be cast to Number.