error[E0308]: mismatched types --> tests/ui-stable/transmute-mut-src-dst-not-references.rs:17:59 | 17 | const SRC_DST_NOT_REFERENCES: &mut usize = transmute_mut!(0usize); | ---------------^^^^^^- | | | | | expected `&mut _`, found `usize` | expected due to this | = note: expected mutable reference `&mut _` found type `usize` help: consider mutably borrowing here | 17 | const SRC_DST_NOT_REFERENCES: &mut usize = transmute_mut!(&mut 0usize); | ++++ warning: this function depends on never type fallback being `()` --> tests/ui-stable/transmute-mut-src-dst-not-references.rs:17:1 | 17 | const SRC_DST_NOT_REFERENCES: &mut usize = transmute_mut!(0usize); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #123748 = help: specify the types explicitly note: in edition 2024, the requirement `!: FromBytes` will fail --> tests/ui-stable/transmute-mut-src-dst-not-references.rs:17:44 | 17 | const SRC_DST_NOT_REFERENCES: &mut usize = transmute_mut!(0usize); | ^^^^^^^^^^^^^^^^^^^^^^ = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default = note: this warning originates in the macro `transmute_mut` (in Nightly builds, run with -Z macro-backtrace for more info) warning: never type fallback affects this call to an `unsafe` function --> tests/ui-stable/transmute-mut-src-dst-not-references.rs:17:44 | 17 | const SRC_DST_NOT_REFERENCES: &mut usize = transmute_mut!(0usize); | ^^^^^^^^^^^^^^^^^^^^^^ | = warning: this will change its meaning in a future release! = note: for more information, see issue #123748 = help: specify the type explicitly = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default = note: this warning originates in the macro `$crate::assert_size_eq` which comes from the expansion of the macro `transmute_mut` (in Nightly builds, run with -Z macro-backtrace for more info)