src/librustc_error_codes/error_codes/E0708.md

   1 `async` non-`move` closures with parameters are currently not supported.
   2
   3 Erroneous code example:
   4
   5 ```compile_fail,edition2018
   6 #![feature(async_closure)]
   7
   8 fn main() {
   9     let add_one = async |num: u8| { // error!
  10         num + 1
  11     };
  12 }
  13 ```
  14
  15 `async` with non-move is currently not supported with the current
  16 version, you can use successfully by using move:
  17
  18 ```edition2018
  19 #![feature(async_closure)]
  20
  21 fn main() {
  22     let add_one = async move |num: u8| { // ok!
  23         num + 1
  24     };
  25 }
  26 ```