Intellij Idea kotlin cannot auto import some operator function such as +

Question

For example:

Class common.number.Number.kt:

operator fun Int.plus(other: BigInteger): BigInteger {
    return BigInteger(this.toString()).add(other)
}

Class common.test.Test.kt:

var i = 1 + BigInteger("1")

Then the Intellij Idea shows an error in class Test.kt. However, if I add the following import, the error disappears:

import common.number.Number.plus

How can I make IntelliJ Idea import this operator function automatically?

Answer 1

It is need because you make special extension operator. It is working same like extension function. Import required because idea need to know which exactly extension you want using. So extensions can be more then one.