(0.0).equals(-0.0)  // false
(0.0) == (-0.0)     // true

Does anyone can explain it?

Similar case was discussed yesterday. Seems like runtime vs compile time calculation. Report a bug.

"-0.0 is considered less than 0.0" from ghedeon's link

@ghedeon thanks for the link!

Yeah, @ghedeon is right, it behaves as specified. The bug that was discussed earlier is about double comparisons in constant expressions: https://youtrack.jetbrains.com/issue/KT-30282

@commanderpepper if so, why does

(0.0) == (-0.0)

return

true

?

The operator

==

uses IEEE-754 order, which considers them equal. The function

equals

uses total order, so these values are distinct.

So, does

==

not actually always translate to a

.equals()

call?

Yes, it's the special case for floating point numbers: https://kotlinlang.org/docs/reference/equality.html#floating-point-numbers-equality

Right, not for these types. In this case

equals

behaves differently

to support generic use cases and provide total ordering

. So, it's good for sorting and stuff.