bad_structures.lean:4:52: error: invalid universe polymorphic structure declaration, the resultant universe is not Prop (i.e., 0), but it may be Prop for some parameter values (solution: use 'l+1' or 'max 1 l') bad_structures.lean:7:54: error: invalid universe polymorphic structure declaration, the resultant universe is not Prop (i.e., 0), but it may be Prop for some parameter values (solution: use 'l+1' or 'max 1 l')