warning: taking a mutable reference to a `const` item
  --> $DIR/E0017.rs:8:30
   |
LL | const CR: &'static mut i32 = &mut C;
   |                              ^^^^^^
   |
   = note: each usage of a `const` item creates a new temporary
   = note: the mutable reference will refer to this temporary, not the original `const` item
note: `const` item defined here
  --> $DIR/E0017.rs:5:1
   |
LL | const C: i32 = 2;
   | ^^^^^^^^^^^^
   = note: `#[warn(const_item_mutation)]` on by default

error[E0764]: mutable borrows of temporaries that have their lifetime extended until the end of the program are not allowed
  --> $DIR/E0017.rs:8:30
   |
LL | const CR: &'static mut i32 = &mut C;
   |                              ^^^^^^ this mutable borrow refers to such a temporary
   |
   = note: Temporaries in constants and statics can have their lifetime extended until the end of the program
   = note: To avoid accidentally creating global mutable state, such temporaries must be immutable
   = help: If you really want global mutable state, try replacing the temporary by an interior mutable `static` or a `static mut`

error[E0596]: cannot borrow immutable static item `X` as mutable
  --> $DIR/E0017.rs:11:39
   |
LL | static STATIC_REF: &'static mut i32 = &mut X;
   |                                       ^^^^^^ cannot borrow as mutable

warning: taking a mutable reference to a `const` item
  --> $DIR/E0017.rs:13:38
   |
LL | static CONST_REF: &'static mut i32 = &mut C;
   |                                      ^^^^^^
   |
   = note: each usage of a `const` item creates a new temporary
   = note: the mutable reference will refer to this temporary, not the original `const` item
note: `const` item defined here
  --> $DIR/E0017.rs:5:1
   |
LL | const C: i32 = 2;
   | ^^^^^^^^^^^^

error[E0764]: mutable borrows of temporaries that have their lifetime extended until the end of the program are not allowed
  --> $DIR/E0017.rs:13:38
   |
LL | static CONST_REF: &'static mut i32 = &mut C;
   |                                      ^^^^^^ this mutable borrow refers to such a temporary
   |
   = note: Temporaries in constants and statics can have their lifetime extended until the end of the program
   = note: To avoid accidentally creating global mutable state, such temporaries must be immutable
   = help: If you really want global mutable state, try replacing the temporary by an interior mutable `static` or a `static mut`

error: aborting due to 3 previous errors; 2 warnings emitted

Some errors have detailed explanations: E0596, E0764.
For more information about an error, try `rustc --explain E0596`.