I’m attempting to build our repo with 1.4-M3, but ...

# eap

[Zac Sweers]

I’m attempting to build our repo with 1.4-M3, but get a strange compile error on a random bit code

The feature “unit conversion” is disabled

private class OnJobDone(
    private val jobDone: (Job) -> Unit,
    val allDone: () -> Unit
)

private val callbacks = OnJobDone(
    jobDone = jobToChannelId andThen trackChannelSynced,
    // Fails on the next line
    allDone = {
      // ...
    }
)

[louiscad]

Does that snippet fail to compile in a new/blank project or on try.kotl.in when you select Kotlin 1.4?

[Zac Sweers]

try.kotl.in only has 1.4-M1. Worked fine with m1 and m2

[Zac Sweers]

still working on getting a consistent local repro, weirdly

[Zac Sweers]

boom got it reproducing locally, finally

[Zac Sweers]

@mikhail.zarechenskiy it looks like this was recently added https://github.com/JetBrains/kotlin/commit/71cbe9768869db76b6ee54f44faca7d75de7be6f#diff-7452279877696ef5b9e37340da047d77

Digging through the code and trying to understand it, but it seems that UnitConversionCallChecker is erroneously being enabled everywhere even if the feature is not explicitly enabled, and now any lambda/function argument that could be subject to it appears to be getting checked by it. Not sure if that’s the right read though.

If I manually enable it via -XXLanguage:+UnitConversion then it works, but for a feature that I’m not explicitly trying to use in existing source this seems like a bug. It also requires that I add -XXLanguage:+NewInference, even though thought the new type inference algorithm was enabled by default in 1.4. Did that change between M2 and M3?

[louiscad]

Linking the issue link you reported for reference: https://youtrack.jetbrains.com/issue/KT-40351