warning: unused import: `util::AU16`
  --> tests/ui-stable/try_transmute_mut-size-increase.rs:13:5
   |
13 | use util::AU16;
   |     ^^^^^^^^^^
   |
   = note: `#[warn(unused_imports)]` on by default

error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
  --> tests/ui-stable/try_transmute_mut-size-increase.rs:20:50
   |
20 |     let increase_size: Result<&mut [u8; 2], _> = try_transmute_mut!(src);
   |                                                  ^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: source type: `u8` (8 bits)
   = note: target type: `[u8; 2]` (16 bits)
   = note: this error originates in the macro `$crate::assert_size_eq` which comes from the expansion of the macro `try_transmute_mut` (in Nightly builds, run with -Z macro-backtrace for more info)