HELP shows ARGS section with all args hidden

[nagisa]

app.arg(Arg::with_name("dummy").possible_value("some val").required(false).hidden(true));

Results in

USAGE:
    app [dummy] [SUBCOMMAND]

FLAGS:
    ...

ARGS:
   { EMPTY }

SUBCOMMANDS:
   ...

Additional comments:

If possible_value is used, USAGE ought to display the possible value instead of arg name?

Rust Version

N/A

Affected Version of clap

2.20.5

[kbknapp]

Thanks for reporting, this should be an easy fix!