error[E0391]: cycle detected when computing type of `Bug::{opaque#0}`
  --> $DIR/issue-53092-2.rs:4:18
   |
LL | type Bug<T, U> = impl Fn(T) -> U + Copy;
   |                  ^^^^^^^^^^^^^^^^^^^^^^
   |
note: ...which requires type-checking `CONST_BUG`...
  --> $DIR/issue-53092-2.rs:6:1
   |
LL | const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: ...which requires computing layout of `Bug<u8, ()>`...
   = note: ...which requires normalizing `Bug<u8, ()>`...
   = note: ...which again requires computing type of `Bug::{opaque#0}`, completing the cycle
note: cycle used when checking item types in top-level module
  --> $DIR/issue-53092-2.rs:1:1
   |
LL | / #![feature(type_alias_impl_trait)]
LL | | #![allow(dead_code)]
LL | |
LL | | type Bug<T, U> = impl Fn(T) -> U + Copy;
...  |
LL | |     CONST_BUG(0);
LL | | }
   | |_^

error[E0277]: the trait bound `U: From<T>` is not satisfied
  --> $DIR/issue-53092-2.rs:9:5
   |
LL |     |x| x.into()
   |     ^^^^^^^^^^^^ the trait `From<T>` is not implemented for `U`
   |
note: required by a bound in `make_bug`
  --> $DIR/issue-53092-2.rs:8:19
   |
LL | fn make_bug<T, U: From<T>>() -> Bug<T, U> {
   |                   ^^^^^^^ required by this bound in `make_bug`
help: consider restricting type parameter `U`
   |
LL | type Bug<T, U: std::convert::From<T>> = impl Fn(T) -> U + Copy;
   |              +++++++++++++++++++++++

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0277, E0391.
For more information about an error, try `rustc --explain E0277`.