warning: taking a mutable reference to a `const` item --> tests/ui-stable/transmute-mut-const.rs:20:52 | 20 | const CONST_CONTEXT: &mut [u8; 2] = transmute_mut!(&mut ARRAY_OF_U8S); | ^^^^^^^^^^^^^^^^^ | = 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 --> tests/ui-stable/transmute-mut-const.rs:17:1 | 17 | const ARRAY_OF_U8S: [u8; 2] = [0u8; 2]; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: `#[warn(const_item_mutation)]` on by default error[E0658]: mutable references are not allowed in constants --> tests/ui-stable/transmute-mut-const.rs:20:52 | 20 | const CONST_CONTEXT: &mut [u8; 2] = transmute_mut!(&mut ARRAY_OF_U8S); | ^^^^^^^^^^^^^^^^^ | = note: see issue #57349 for more information error[E0015]: cannot call non-const fn `transmute_mut::<'_, '_, [u8; 2], [u8; 2]>` in constants --> tests/ui-stable/transmute-mut-const.rs:20:37 | 20 | const CONST_CONTEXT: &mut [u8; 2] = transmute_mut!(&mut ARRAY_OF_U8S); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: calls in constants are limited to constant functions, tuple structs and tuple variants = note: this error originates in the macro `transmute_mut` (in Nightly builds, run with -Z macro-backtrace for more info) error[E0716]: temporary value dropped while borrowed --> tests/ui-stable/transmute-mut-const.rs:20:57 | 20 | const CONST_CONTEXT: &mut [u8; 2] = transmute_mut!(&mut ARRAY_OF_U8S); | --------------------^^^^^^^^^^^^- | | | | | creates a temporary value which is freed while still in use | temporary value is freed at the end of this statement | using this value as a constant requires that borrow lasts for `'static`