<Why doesn't Kotlin treat numbers as "Int" by defa...

# stackoverflow

[user]

Why doesn't Kotlin treat numbers as "Int" by default inside sumOf function lambda?
In the below code:
val sum = listOf(1, 2, 3).sumOf { if (it % 2 == 0) 1 else 0 }

Kotlin gives the following error:
Kotlin: Overload resolution ambiguity:
public inline fun Iterable.sumOf(selector: (TypeVariable(T)) -> Int): Int defined in kotlin.collections
public inline fun Iterable.sumOf(selector: (TypeVariable(T)) -> Long): Long defined in kotlin.collections

Playground
If I explicitly use toInt(), the error is gone...