tests/ui/nll/issue-53040.stderr

   1 error: captured variable cannot escape `FnMut` closure body
   2   --> $DIR/issue-53040.rs:3:8
   3    |
   4 LL |     let mut v: Vec<()> = Vec::new();
   5    |         ----- variable defined here
   6 LL |     || &mut v;
   7    |      - ^^^^^-
   8    |      | |    |
   9    |      | |    variable captured here
  10    |      | returns a reference to a captured variable which escapes the closure body
  11    |      inferred to be a `FnMut` closure
  12    |
  13    = note: `FnMut` closures only have access to their captured variables while they are executing...
  14    = note: ...therefore, they cannot allow references to captured variables to escape
  15
  16 error: aborting due to previous error
  17