warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/specialization-transmute.rs:3:12
   |
LL | #![feature(specialization)]
   |            ^^^^^^^^^^^^^^
   |
   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
   = help: consider using `min_specialization` instead, which is more stable and complete
   = note: `#[warn(incomplete_features)]` on by default

error[E0284]: type annotations needed: cannot satisfy `T <: <T as Default>::Id`
  --> $DIR/specialization-transmute.rs:16:9
   |
LL |         self
   |         ^^^^ cannot satisfy `T <: <T as Default>::Id`

error[E0284]: type annotations needed: cannot satisfy `<u8 as Default>::Id == Option<NonZeroU8>`
  --> $DIR/specialization-transmute.rs:27:13
   |
LL |     let s = transmute::<u8, Option<NonZeroU8>>(0);
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot satisfy `<u8 as Default>::Id == Option<NonZeroU8>`
   |
note: required by a bound in `transmute`
  --> $DIR/specialization-transmute.rs:21:25
   |
LL | fn transmute<T: Default<Id = U>, U: Copy>(t: T) -> U {
   |                         ^^^^^^ required by this bound in `transmute`

error: aborting due to 2 previous errors; 1 warning emitted

For more information about this error, try `rustc --explain E0284`.