error[E0308]: if and else have incompatible types
  --> $DIR/region-invariant-static-error-reporting.rs:24:15
   |
LL |       let bad = if x.is_some() {
   |  _______________^
LL | |         x.unwrap()
LL | |     } else {
LL | |         mk_static()
LL | |     };
   | |_____^ lifetime mismatch
   |
   = note: expected type `Invariant<'a>`
              found type `Invariant<'static>`
note: the lifetime 'a as defined on the function body at 23:10...
  --> $DIR/region-invariant-static-error-reporting.rs:23:10
   |
LL | fn unify<'a>(x: Option<Invariant<'a>>, f: fn(Invariant<'a>)) {
   |          ^^
   = note: ...does not necessarily outlive the static lifetime

error: aborting due to previous error

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