`PW0305`

non_exhaustive_match

The program must hold to this: a match must cover every value its scrutinee can take.

A program the compiler refuses with it

Refused: PW0305

module shapes

type Shape =
    | Circle(Int)
    | Square(Int)
    | Point

fn area(s: Shape) -> Int !{} {
    match s {
        Circle(r) => 3 * r * r,
        Square(side) => side * side,
    }
}

From A case forgotten, in Why Pleris. A test holds the guide's examples to the compiler.

Reading the diagnostic

pw check prints the code in brackets, [PW0305], with the sentence above and the place in your program. Errors and diagnostics explains how to read one, and every code is listed with its rule.