error[E0277]: the trait bound `T: Pointee` is not satisfied
  --> $DIR/issue-81199.rs:5:17
   |
LL |     components: PtrComponents<T>,
   |                 ^^^^^^^^^^^^^^^^ the trait `Pointee` is not implemented for `T`
   |
note: required by a bound in `PtrComponents`
  --> $DIR/issue-81199.rs:11:25
   |
LL | struct PtrComponents<T: Pointee + ?Sized> {
   |                         ^^^^^^^ required by this bound in `PtrComponents`
help: consider further restricting this bound
   |
LL | union PtrRepr<T: ?Sized + Pointee> {
   |                         +++++++++

error[E0740]: field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union
  --> $DIR/issue-81199.rs:5:5
   |
LL |     components: PtrComponents<T>,
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>`
help: wrap the field type in `ManuallyDrop<...>`
   |
LL |     components: std::mem::ManuallyDrop<PtrComponents<T>>,
   |                 +++++++++++++++++++++++                +

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0277, E0740.
For more information about an error, try `rustc --explain E0277`.