error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:20:9
   |
LL |         (*(a as *const _ as *mut String)).push_str(" world");
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: the lint level is defined here
  --> $DIR/reference_casting.rs:4:9
   |
LL | #![deny(invalid_reference_casting)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:22:9
   |
LL |         *(a as *const _ as *mut _) = String::from("Replaced");
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:24:9
   |
LL |         *(a as *const _ as *mut String) += " world";
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:26:25
   |
LL |         let _num = &mut *(num as *const i32 as *mut i32);
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:28:25
   |
LL |         let _num = &mut *(num as *const i32).cast_mut();
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:30:20
   |
LL |         let _num = *{ num as *const i32 }.cast_mut();
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:32:9
   |
LL |         *std::ptr::from_ref(num).cast_mut() += 1;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:34:9
   |
LL |         *std::ptr::from_ref({ num }).cast_mut() += 1;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:36:9
   |
LL |         *{ std::ptr::from_ref(num) }.cast_mut() += 1;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
  --> $DIR/reference_casting.rs:38:9
   |
LL |         *(std::ptr::from_ref({ num }) as *mut i32) += 1;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 10 previous errors