const n = 6;
const foo = fn() s32 {
    var a: s32 = 0;
    while (true) {
        if (a == n) {
            return a;
        }

        a += 1;
    }
}

const Error = error{
    unexpected_result,
};

const main = fn() Error!void{
    if (foo() - n != 0) {
        return Error.unexpected_result;
    }
}