Why == generates compilation error on different types in Kotlin

Question

The following code cannot be compiled:

if ("2" == 3) {
  //do something
}

Error: Kotlin: Operator '==' cannot be applied to 'String' and 'Int'

However, Kotlin reports that this is structural equality and is translated to a?.equals(b) ?: (b === null)

: https://kotlinlang.org/docs/reference/equality.html .

So what's going on here? How it works?

+3

oshai 10 jul. 17 at 21:33

1 answer

holi-java · Answer 1 · 2017-07-10T21:57:25+0000

this is a Kotlin bug reported as KT-4071 in youtrack, but a priority Major

, so I think this will be fixed quickly. eg:

val ok = "2".equals(3) // works fine
val error = "2" == 3 // compilation error