error: methods and doc comments are not allowed for flattened entry
  --> $DIR/flatten_and_methods.rs:22:19
   |
22 |     #[clap(short, flatten)]
   |                   ^^^^^^^

error[E0277]: the trait bound `Opt: std::convert::From<clap::parse::matches::arg_matches::ArgMatches>` is not satisfied
  --> $DIR/flatten_and_methods.rs:19:10
   |
19 | #[derive(Clap, Debug)]
   |          ^^^^ the trait `std::convert::From<clap::parse::matches::arg_matches::ArgMatches>` is not implemented for `Opt`