Bash completion no longer completes arg possible_values

[vincentdephily]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Rust Version

1.60.0

Clap Version

3.1.16 (clap) 3.1.3 (clap_complete)

Minimal reproducible code

use clap::*;
use clap_complete::*;

fn main() {
    let mut cli = App::new("foo").arg(Arg::new("foo").long("foo").possible_values(&["bar", "baz"]));
    generate(Shell::Bash, &mut cli, "foo", &mut std::io::stdout());
}

Steps to reproduce the bug with the above code

cargo run | rg -C1 COMPREPLY

Actual Behaviour

                --foo)
                    COMPREPLY=($(compgen -W "" -- "${cur}"))
                    return 0

Expected Behaviour

                --foo)
                    COMPREPLY=($(compgen -W "bar baz" -- "${cur}"))
                    return 0

Additional Context

This is a regression introduced in clap_complete 3.1.1. Versions 3.1.0 and earlier (including 2.x series I'm currently upgrading from) are fine.

Debug Output

No response

[epage]

Fix released in v3.1.4