Can someone explain why this works? ```fun listOfArrays(): List<Array<Any>> { return l...

# announcements

[mbonnin]

Can someone explain why this works?

fun listOfArrays(): List<Array<Any>> {
  return listOf(arrayOf("1", 0))
}

But not this?

fun listOfArrays(): List<Array<Any>> {
  // Type mismatch: inferred type is List<Array<out {Comparable<*> & java.io.Serializable}>> but List<Array<Any>> was expected
  return listOf(arrayOf("1", 0)).map { it }
}

[louiscad]

Probably a type inference bug that is worth reporting on kotl.in/issue if it's reproducible in 1.4.20-M1.

[mbonnin]

It's with 1.4.10 , I'll try 1.4.20-M1 👍

[mbonnin]

My initial sample was wrong, it missed a layer of List<> . I just updated it but that doesn't change the issue. I filed https://youtrack.jetbrains.com/issue/KT-42586

[Nir]

This looks a lot like the issue that caused plsusElement to be added

[Nir]

plus has some very weird behavior for lists of lists

[Nir]

https://youtrack.jetbrains.com/issue/KT-9992#focus=Comments-27-1283874.0-0

[ilya.gorbunov]

No, it isn't related to KT-9992. Most likely it's the same problem as https://youtrack.jetbrains.com/issue/KT-17115, where compiler is unable to infer types in a chain of method calls.