error[E0277]: the trait bound `E: From<()>` is not satisfied
  --> $DIR/never-value-fallback-issue-66757.rs:28:26
   |
LL |     <E as From<_>>::from(never);
   |     -------------------- ^^^^^ the trait `From<()>` is not implemented for `E`
   |     |
   |     required by a bound introduced by this call
   |
   = help: the trait `From<!>` is implemented for `E`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.