std.getopt: Unexpected behavior when using incremental options

[Cym13]

On Sunday, 29 July 2018 at 09:28:41 UTC, Ky-Anh Huynh wrote:
> Hi,
>
> I am using std.getopt and expect to parse an incremental option 
> with different names: --long, --longer, -l. The sample code is 
> here
>
> [...]

I think -long is actually taken as -l -o -n -g here. Since you 
didn't define -o, -n and -g it prints a usage error.