Could not compile `loop-rs`

error[E0631]: type mismatch in function arguments
   --> /Users/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/loop-rs-0.6.1/src/main.rs:238:48
    |
238 |     #[structopt(long = "for", parse(from_str = "get_values"))]
    |                                                ^^^^^^^^^^^^ expected signature of `fn(&str) -> _`
...
322 | fn get_values(input: &&str) -> Vec<String> {
    | ------------------------------------------ found signature of `for<'r, 's> fn(&'r &'s str) -> _`

error[E0631]: type mismatch in function arguments
   --> /Users/marcin/.cargo/registry/src/github.com-1ecc6299db9ec823/loop-rs-0.6.1/src/main.rs:266:69
    |
266 |     #[structopt(short = "r", long = "until-error", parse(from_str = "get_error_code"))]
    |                                                                     ^^^^^^^^^^^^^^^^ expected signature of `fn(&str) -> _`
...
314 | fn get_error_code(input: &&str) -> ErrorCode {
    | -------------------------------------------- found signature of `for<'r, 's> fn(&'r &'s str) -> _`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0631`.
error: failed to compile `loop-rs v0.6.1`, intermediate artifacts can be found at `/var/folders/gw/053czpm957z2rq6k8xqvnxx00000gn/T/cargo-installBihqf5`

Caused by:
  could not compile `loop-rs`

My rust version:

$ rustup show
Default host: x86_64-apple-darwin
rustup home:  /Users/marcin/.rustup

installed toolchains
--------------------

stable-x86_64-apple-darwin (default)
nightly-x86_64-apple-darwin

active toolchain
----------------

stable-x86_64-apple-darwin (default)
rustc 1.54.0 (a178d0322 2021-07-26)

Start by reproducing the failure with the stable Rust toolchain and inspect loop-rs 0.6.1/src/main.rs around lines 238, 266, 314, and 322. Compare the parser callbacks with the signatures expected by structopt, then verify that loop-rs compiles and installs successfully.