error: queries overflow the depth limit!
  --> $DIR/recursive.rs:10:13
   |
LL |     let _ = RECUR::<()>;
   |             ^^^^^^^^^^^
   |
   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "30"]` attribute to your crate (`recursive`)
   = note: query depth increased by 17 when simplifying constant for the type system `RECUR`

error: aborting due to 1 previous error