This is disappointing. So if I inline an `Int` tha...

# random

[thomasnield]

This is disappointing. So if I inline an Int that is a factor of 5, I can't enforce this due to private constructor not being allowed?

[hudsonb]

Ya, it’s because of java interop

[hudsonb]

Wish it could cause then you could create something like Vector3(xyz: DoubleArray) and verify that xyz was actually length 3

[thomasnield]

Yeah... to me this is the whole reason to use inline classes: creating a compiler-restricted set of primitive values that are still primitives. It's really a bummer.

[robin]

Was going to say that an init block might do the trick, but that's also not allowed for inline classes... That's disappointing indeed

[louiscad]

You can't enforce it yet. This is something they are working on.

[hudsonb]

@thomasnield Looking at UByte I noticed they mark the constructor as internal, which isn't allowed normally, but is enabled via @Suppress("NON_PUBLIC_PRIMARY_CONSTRUCTOR_OF_INLINE_CLASS")

[hudsonb]

Which allows you to do this:

@Suppress("NON_PUBLIC_PRIMARY_CONSTRUCTOR_OF_INLINE_CLASS")
inline class FactorOfFive internal constructor(internal val value: Int)

With a "construction extension" like this:

fun FactorOfFive(value: Int) = when {
    value % 5 == 0 -> FactorOfFive(value)
    else -> throw IllegalArgumentException("Value is not a factor of 5")
}

[thomasnield]

@hudsonb cool, so it looks like something is in the works and already in experimental stages