error[E0764]: mutable references are not allowed in constants --> $DIR/E0388.rs:4:30 | LL | const CR: &'static mut i32 = &mut C; | ^^^^^^ `&mut` is only allowed in `const fn` error[E0019]: static contains unimplemented expression type --> $DIR/E0388.rs:5:39 | LL | static STATIC_REF: &'static mut i32 = &mut X; | ^^^^^^ | = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable error[E0764]: mutable references are not allowed in statics --> $DIR/E0388.rs:5:39 | LL | static STATIC_REF: &'static mut i32 = &mut X; | ^^^^^^ `&mut` is only allowed in `const fn` error[E0596]: cannot borrow immutable static item `X` as mutable --> $DIR/E0388.rs:5:39 | LL | static STATIC_REF: &'static mut i32 = &mut X; | ^^^^^^ cannot borrow as mutable error[E0764]: mutable references are not allowed in statics --> $DIR/E0388.rs:8:38 | LL | static CONST_REF: &'static mut i32 = &mut C; | ^^^^^^ `&mut` is only allowed in `const fn` error: aborting due to 5 previous errors Some errors have detailed explanations: E0019, E0596, E0764. For more information about an error, try `rustc --explain E0019`.