diagnostics: can we suggest &* here?

[matthiaskrgr]

I spent {way too much} time on this yesterday:

extern crate clap;
fn main() {
    let v = "0.1".to_string();
    let app = clap::App::new("hello world").version(v);
}

this code fails to build with

error[E0277]: the trait bound `&str: std::convert::From<std::string::String>` is not satisfied
 --> src/main.rs:4:45
  |
4 |     let app = clap::App::new("hello world").version(v);
  |                                             ^^^^^^^ the trait `std::convert::From<std::string::String>` is not implemented for `&str`
  |
  = note: required because of the requirements on the impl of `std::convert::Into<&str>` for `std::string::String`
error: aborting due to previous error

passing v by reference doesn't help either ( .version(&v), the msg is almost identical then).

What fixed this for me in the end was .version(&*v).

Is there a way we could suggest to the user to use &* in this example?

the version method signature can be found here

[Havvy]

version signature:

pub fn version<S: Into<&'b str>>(self, ver: S) -> Self

Looks like you can just do let v = "0.1"; and pass it in that way? Or even const VERSION: &str = "0.1";

[matthiaskrgr]

Indeed, but in my original code I had a function to generate the version which returned a String,

[memoryruins]

A similar issue was opened last week on clap's repository clap-rs/clap#1336