error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:7:39
   |
LL |     fn this_wont_hurt_a_bit(&self) -> &mut Foo {
   |                                       ^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:7:29
   |
LL |     fn this_wont_hurt_a_bit(&self) -> &mut Foo {
   |                             ^^^^^
   = note: `-D clippy::mut-from-ref` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::mut_from_ref)]`

error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:15:25
   |
LL |     fn ouch(x: &Foo) -> &mut Foo;
   |                         ^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:15:16
   |
LL |     fn ouch(x: &Foo) -> &mut Foo;
   |                ^^^^

error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:25:21
   |
LL | fn fail(x: &u32) -> &mut u16 {
   |                     ^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:25:12
   |
LL | fn fail(x: &u32) -> &mut u16 {
   |            ^^^^

error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:31:50
   |
LL | fn fail_lifetime<'a>(x: &'a u32, y: &mut u32) -> &'a mut u32 {
   |                                                  ^^^^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:31:25
   |
LL | fn fail_lifetime<'a>(x: &'a u32, y: &mut u32) -> &'a mut u32 {
   |                         ^^^^^^^

error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:37:67
   |
LL | fn fail_double<'a, 'b>(x: &'a u32, y: &'a u32, z: &'b mut u32) -> &'a mut u32 {
   |                                                                   ^^^^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:37:27
   |
LL | fn fail_double<'a, 'b>(x: &'a u32, y: &'a u32, z: &'b mut u32) -> &'a mut u32 {
   |                           ^^^^^^^     ^^^^^^^

error: mutable borrow from immutable input(s)
  --> tests/ui/mut_from_ref.rs:53:35
   |
LL | unsafe fn also_broken(x: &u32) -> &mut u32 {
   |                                   ^^^^^^^^
   |
note: immutable borrow here
  --> tests/ui/mut_from_ref.rs:53:26
   |
LL | unsafe fn also_broken(x: &u32) -> &mut u32 {
   |                          ^^^^

error: aborting due to 6 previous errors