error[E0308]: mismatched types
  --> $DIR/occurs-check-3.rs:4:24
   |
LL | fn main() { let c; c = Clam::A(c); match c { Clam::A::<isize>(_) => { } } }
   |                        ^^^^^^^^^^ cyclic type of infinite size

error: aborting due to 1 previous error

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