Error code E0796
You have created a reference to a mutable static.
Erroneous code example:
#![allow(unused)] fn main() { static mut X: i32 = 23; fn work() { let _val = unsafe { X }; } let x_ref = unsafe { &mut X }; work(); // The next line has Undefined Behavior! // `x_ref` is a mutable reference and allows no aliases, // but `work` has been reading the reference between // the moment `x_ref` was created and when it was used. // This violates the uniqueness of `x_ref`. *x_ref = 42; }
A reference to a mutable static has lifetime 'static
. This is very dangerous
as it is easy to accidentally overlap the lifetime of that reference with
other, conflicting accesses to the same static.
References to mutable statics are a hard error in the 2024 edition.