error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
  --> $DIR/issue-62387-suggest-iter-mut.rs:18:27
   |
LL |     v.iter().for_each(|a| a.double());
   |                        -  ^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
   |                        |
   |                        consider changing this binding's type to be: `&mut A`
   |
help: you may want to use `iter_mut` here
   |
LL |     v.iter_mut().for_each(|a| a.double());
   |       ~~~~~~~~

error[E0596]: cannot borrow `*a` as mutable, as it is behind a `&` reference
  --> $DIR/issue-62387-suggest-iter-mut.rs:25:39
   |
LL |     v.iter().rev().rev().for_each(|a| a.double());
   |                                    -  ^ `a` is a `&` reference, so the data it refers to cannot be borrowed as mutable
   |                                    |
   |                                    consider changing this binding's type to be: `&mut A`
   |
help: you may want to use `iter_mut` here
   |
LL |     v.iter_mut().rev().rev().for_each(|a| a.double());
   |       ~~~~~~~~

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0596`.