error[E0308]: mismatched types
  --> $DIR/rfc1623.rs:28:8
   |
LL |     f: &id,
   |        ^^^ one type is more general than the other
   |
   = note: expected trait `for<'a, 'b> Fn<(&'a Foo<'b>,)>`
              found trait `Fn<(&Foo<'_>,)>`

error[E0308]: mismatched types
  --> $DIR/rfc1623.rs:28:8
   |
LL |     f: &id,
   |        ^^^ one type is more general than the other
   |
   = note: expected trait `for<'a, 'b> Fn<(&'a Foo<'b>,)>`
              found trait `Fn<(&Foo<'_>,)>`

error: implementation of `FnOnce` is not general enough
  --> $DIR/rfc1623.rs:28:8
   |
LL |     f: &id,
   |        ^^^ implementation of `FnOnce` is not general enough
   |
   = note: `fn(&'2 Foo<'_>) -> &'2 Foo<'_> {id::<&'2 Foo<'_>>}` must implement `FnOnce<(&'1 Foo<'b>,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `FnOnce<(&'2 Foo<'_>,)>`, for some specific lifetime `'2`

error: implementation of `FnOnce` is not general enough
  --> $DIR/rfc1623.rs:28:8
   |
LL |     f: &id,
   |        ^^^ implementation of `FnOnce` is not general enough
   |
   = note: `fn(&Foo<'2>) -> &Foo<'2> {id::<&Foo<'2>>}` must implement `FnOnce<(&'a Foo<'1>,)>`, for any lifetime `'1`...
   = note: ...but it actually implements `FnOnce<(&Foo<'2>,)>`, for some specific lifetime `'2`

error: aborting due to 4 previous errors

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