error: mutable references in const fn are unstable --> $DIR/ranged_ints2_const.rs:11:9 | LL | let y = &mut x.0; //~ ERROR references in const fn are unstable | ^ error: mutable references in const fn are unstable --> $DIR/ranged_ints2_const.rs:18:9 | LL | let y = unsafe { &mut x.0 }; //~ ERROR mutable references in const fn are unstable | ^ error[E0133]: mutation of layout constrained field is unsafe and requires unsafe function or block --> $DIR/ranged_ints2_const.rs:11:13 | LL | let y = &mut x.0; //~ ERROR references in const fn are unstable | ^^^^^^^^ mutation of layout constrained field | = note: mutating layout constrained fields cannot statically be checked for valid values error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0133`.