error[E0072]: recursive types `Foo` and `Bar` have infinite size
  --> $DIR/variance-regions-unused-indirect.rs:3:1
   |
LL | enum Foo<'a> {
   | ^^^^^^^^^^^^
LL |
LL |     Foo1(Bar<'a>)
   |          ------- recursive without indirection
...
LL | enum Bar<'a> {
   | ^^^^^^^^^^^^
LL |     Bar1(Foo<'a>)
   |          ------- recursive without indirection
   |
help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle
   |
LL ~     Foo1(Box<Bar<'a>>)
LL | }
LL |
LL | enum Bar<'a> {
LL ~     Bar1(Box<Foo<'a>>)
   |

error[E0392]: lifetime parameter `'a` is never used
  --> $DIR/variance-regions-unused-indirect.rs:3:10
   |
LL | enum Foo<'a> {
   |          ^^ unused lifetime parameter
   |
   = help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`

error[E0392]: lifetime parameter `'a` is never used
  --> $DIR/variance-regions-unused-indirect.rs:8:10
   |
LL | enum Bar<'a> {
   |          ^^ unused lifetime parameter
   |
   = help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0072, E0392.
For more information about an error, try `rustc --explain E0072`.