error[E0412]: cannot find type `as_str` in this scope
  --> $DIR/mir-build-2021-closure-capture-ice-110453-2.rs:8:47
   |
LL | pub fn dup(f: impl Fn(i32) -> i32) -> impl Fn(as_str) -> i32 {
   |                                               ^^^^^^ not found in this scope

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0412`.