Do equality checks in `when` statements not trigge...

# random

[Simon Duchastel]

Do equality checks in when statements not trigger a smart cast?

ie:

sealed interface Foo
object Bar: Foo
object Baz: Foo

when (foo) {
    Bar -> // typechecked as Foo, cannot use as Bar without a casting
    is Baz -> // smart-cast as Baz
}

I thought using the equality syntax would allow smart-casting, but I get a type error in my project if I do this. I tried on Kotlin 2.2.20 (link) and also on an older Kotlin version too (link)

[Simon Duchastel]

For some reason I swear something like this has worked for me in the past, but clearly not 😅

[ephemient]

equals is overridable, so foo.equals(Bar) does not necessarily mean that foo is Bar

[ephemient]

of course in this case you can see that there are no overrides of equals, but in general it is possible

[Simon Duchastel]

Ah there's no satisfying "aha" emoji

[Simon Duchastel]

I didn't consider the case of override equals, thanks @ephemient!

[Youssef Shoaib [MOD]]

I wish it'd work with data object at least, but I guess you still could override equals there

[Simon Duchastel]

Yeah this feels like something that should just work, but the nice thing is the fix is easy (just use an is check) and it's good that Kotlin is keeping a foot gun away from us by ensuring an overridden equals doesn't blow up the program