No visibility when extending function for a data class from its companion object

Question

Given the following data class:

data class Coords(val x: Int, val y: Int) {
    companion object CoordsOps {
        private val shiftTable: Map<Direction, Pair<Int, Int>> = mapOf(
            Direction.North to Pair(0, 1),
            Direction.East to Pair(1, 0),
            Direction.South to Pair(0, -1),
            Direction.West to Pair(-1, 0)
        )

        private operator fun Coords.plus(increment: Pair<Int, Int>): Coords =
            Coords(x + increment.first, y + increment.second)

        fun Coords.shift(direction: Direction): Coords = this + shiftTable.getValue(direction)
    }
}

I'm not able to use the extension function shift() from outside that object. I would like to use Coords.shift(direction) .

What am I doing wrong?

Answer 1

You should be able to. I copied your code exactly and was able to call extension function shift from another file.

Perhaps you're missing the import? Or calling it incorrectly? Try this

import <your_package>.Coords.CoordsOps.shift

val y = Coords(3, 4).shift(Direction.East)