universes u v -- `Type u` version can be defined without this option, but I get the same error set_option bootstrap.inductiveCheckResultingUniverse false in inductive PEmpty : Sort u -- `#check` works set_option pp.all true in #check fun {α : Sort v} => PEmpty.rec (fun _ => α) -- but `def` doesn't work -- error: (kernel) compiler failed to infer low level type, unknown declaration 'PEmpty.rec' def PEmpty.elim {α : Sort v} := PEmpty.rec (fun _ => α)