src/test/ui/typeck/issue-57404.stderr

   1 error[E0277]: `&mut ()` is not a tuple
   2   --> $DIR/issue-57404.rs:6:41
   3    |
   4 LL |     handlers.unwrap().as_mut().call_mut(&mut ());
   5    |                                -------- -^^^^^^
   6    |                                |        |
   7    |                                |        the trait `Tuple` is not implemented for `&mut ()`
   8    |                                |        help: consider removing the leading `&`-reference
   9    |                                required by a bound introduced by this call
  10    |
  11 note: required by a bound in `call_mut`
  12   --> $SRC_DIR/core/src/ops/function.rs:LL:COL
  13
  14 error: aborting due to previous error
  15
  16 For more information about this error, try `rustc --explain E0277`.