const Error = error{
    unexpected_result,
};

const main = fn() Error!void {
    const a: s32 = 1;
    const b: s32 = 2;
    const c: s32 = a + b;
    const d: s32 = 3;
    const e: s32 = d - c;
    if (e != 0) {
        return Error.unexpected_result;
    }
}