Compile time verification of default value

[diegobernardes]

It's possible to verify a default_value during compilation?

#[clap(short, long, default_value = "-123")]
value: u64,

It would be awesome to have a compilation error here.

[pksunkara]

It might be possible for since this is part of clap_derive. Can you please create an issue for this?

[diegobernardes]

Feature request: #2064