src/test/ui/closure_context/issue-26046-fn-mut.stderr

   1 error[E0525]: expected a closure that implements the `Fn` trait, but this closure only implements `FnMut`
   2   --> $DIR/issue-26046-fn-mut.rs:14:19
   3    |
   4 14 |       let closure = || {
   5    |  ___________________^
   6 15 | |         num += 1;
   7 16 | |     };
   8    | |_____^
   9 17 |
  10 18 |       Box::new(closure)
  11    |       ----------------- the requirement to implement `Fn` derives from here
  12    |
  13 note: closure is `FnMut` because it mutates the variable `num` here
  14   --> $DIR/issue-26046-fn-mut.rs:15:9
  15    |
  16 15 |         num += 1;
  17    |         ^^^
  18
  19 error: aborting due to previous error
  20