error: the function `takes_an_immutable_reference` doesn't need a mutable reference
  --> $DIR/mut_reference.rs:17:34
   |
LL |     takes_an_immutable_reference(&mut 42);
   |                                  ^^^^^^^
   |
   = note: `-D clippy::unnecessary-mut-passed` implied by `-D warnings`

error: the function `as_ptr` doesn't need a mutable reference
  --> $DIR/mut_reference.rs:19:12
   |
LL |     as_ptr(&mut 42);
   |            ^^^^^^^

error: the method `takes_an_immutable_reference` doesn't need a mutable reference
  --> $DIR/mut_reference.rs:23:44
   |
LL |     my_struct.takes_an_immutable_reference(&mut 42);
   |                                            ^^^^^^^

error: this argument is a mutable reference, but not used mutably
  --> $DIR/mut_reference.rs:11:44
   |
LL |     fn takes_a_mutable_reference(&self, a: &mut i32) {}
   |                                            ^^^^^^^^ help: consider changing to: `&i32`
   |
   = note: `-D clippy::needless-pass-by-ref-mut` implied by `-D warnings`

error: aborting due to 4 previous errors