1error[E0308]: mismatched types
2  --> tests/ui-nightly/transmute-mut-src-immutable.rs:17:37
3   |
417 |     let _: &mut u8 = transmute_mut!(&0u8);
5   |                      ---------------^^^^-
6   |                      |              |
7   |                      |              types differ in mutability
8   |                      expected due to this
9   |
10   = note: expected mutable reference `&mut _`
11                      found reference `&u8`
12
13warning: this function depends on never type fallback being `()`
14  --> tests/ui-nightly/transmute-mut-src-immutable.rs:15:1
15   |
1615 | fn ref_src_immutable() {
17   | ^^^^^^^^^^^^^^^^^^^^^^
18   |
19   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
20   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
21   = help: specify the types explicitly
22note: in edition 2024, the requirement `!: FromBytes` will fail
23  --> tests/ui-nightly/transmute-mut-src-immutable.rs:17:22
24   |
2517 |     let _: &mut u8 = transmute_mut!(&0u8);
26   |                      ^^^^^^^^^^^^^^^^^^^^
27   = note: `#[warn(dependency_on_unit_never_type_fallback)]` on by default
28   = note: this warning originates in the macro `transmute_mut` (in Nightly builds, run with -Z macro-backtrace for more info)
29
30warning: never type fallback affects this call to an `unsafe` function
31  --> tests/ui-nightly/transmute-mut-src-immutable.rs:17:22
32   |
3317 |     let _: &mut u8 = transmute_mut!(&0u8);
34   |                      ^^^^^^^^^^^^^^^^^^^^
35   |
36   = warning: this will change its meaning in a future release!
37   = note: for more information, see issue #123748 <https://github.com/rust-lang/rust/issues/123748>
38   = help: specify the type explicitly
39   = note: `#[warn(never_type_fallback_flowing_into_unsafe)]` on by default
40   = 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)
41