error[E0407]: method `from` is not a member of trait `Fn`
  --> $DIR/issue-87558.rs:6:5
   |
LL |     fn from() {}
   |     ^^^^^^^^^^^^ not a member of trait `Fn`

error[E0183]: manual implementations of `Fn` are experimental
  --> $DIR/issue-87558.rs:3:6
   |
LL | impl Fn(&isize) for Error {
   |      ^^^^^^^^^^ manual implementations of `Fn` are experimental
   |
   = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable

error[E0229]: associated type bindings are not allowed here
  --> $DIR/issue-87558.rs:3:6
   |
LL | impl Fn(&isize) for Error {
   |      ^^^^^^^^^^ associated type not allowed here

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0183, E0229, E0407.
For more information about an error, try `rustc --explain E0183`.