const main = fn () s32 {
    const ch = 'a';
    var buffer: [1]u8 = undefined;
    var ptr: &[1]u8 = buffer.&;
    var index: usize = 0;
    ptr[index] = ch;
    const sub: u8 = ptr[index] - ch;
    const result: u32 = sub;
    return #cast(result);
}