How hard for compiler it would be to not ask final...

# compiler

[Eugen Martynov]

How hard for compiler it would be to not ask final else case for

fun getText(ignoreOptions: Boolean, option: Option): String { 
    return when {
        ignoreOptions -> "Ignored"
        option is OptionA -> "A: ${option.number}"
        option is OptionB -> option.text
    }
}

When Option sealed class and has only OptionA and OptionB as implementations

[Eugen Martynov]

oke probably it is open when if it would be something like when(ingoredOption, option){} to give copmpiler glimpse it is only things I'm interested here.

[Benoit Quenaudon]

fun getText(ignoreOptions: Boolean, option: Option): String {
  if (ignoreOptions) return "Ignored"

  when (option) {
    is OptionA -> "A: ${option.number}"
    is OptionB -> option.text
  }
}

[Vampire]

s/when/return when/ 🙂

[Youssef Shoaib [MOD]]

This is already possible with when guards:

fun getText(ignoreOptions: Boolean, option: Option): String { 
    return when (option) {
        else if ignoreOptions -> "Ignored"
        is OptionA -> "A: ${option.number}"
        is OptionB -> option.text
    }
}

[Vampire]

Since which language version is that valid syntax?

[Vampire]

Ah, 2.1 preview 2.2 stable

[Vampire]

TIL

[CLOVIS]

Follow https://youtrack.jetbrains.com/issue/KT-80334/Compute-exhaustiveness-for-whens-without-subject