error[E0308]: mismatched types
  --> $DIR/issue-57843.rs:23:9
   |
LL |     Foo(Box::new(|_| ())); //~ ERROR mismatched types
   |         ^^^^^^^^^^^^^^^^ one type is more general than the other
   |
   = note: expected type `std::ops::FnOnce<(&'a bool,)>`
              found type `std::ops::FnOnce<(&bool,)>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.