Why doesn't `Lazy` implement `equals` and `hashc...

# stdlib

[Mikhail]

Why doesn't Lazy implement equals and hashcode ?

[Dominaezzz]

What does it mean for two `Lazy`s to be equal?

[Mikhail]

Both are initialized and both values are equal.

[Mikhail]

this is literally stupid

[ephemient]

so == could change depending on when whether it's been read or not? no, that's terrible.

[Mikhail]

so you are assuming that one should never write equals & hashcode for mutable objects?

[Dominaezzz]

Yeah I thought that as well. While I don't like the idea of a == for Lazy , I can't objectively justify it.

[ephemient]

OK if the mutation is explicit

[jw]

Lazy is a service object which produces a value, not a value object itself. Identity is the correct implementation of equals and hashCode.

[Dominaezzz]

Also, if you have Lazy<String> and Lazy<List<*>> . If they're both uninitialised, should they be equal? (Note that you can't do runtime type checks)

[ephemient]

well, you'll be prevented from writing that == just based in static types, usually

[ephemient]

but should lazy { println("a"); 0 } == lazy { println("b"); 0 }?

[Mikhail]

Ok, this sounds convincing.

[Mikhail]

Thank you for your explanations