alt/error_virtual_type2_alt5.nit:25,2--30,10: Error: circularity of virtual type definition: T <-> U.
alt/error_virtual_type2_alt5.nit:38,23: Redef Error: expected `Comparable` for return type; got `T`.
alt/error_virtual_type2_alt5.nit:25,2--30,10: Error: circularity of virtual type definition: T <-> U.
alt/error_virtual_type2_alt5.nit:38,23: Redef Error: expected `Comparable` for return type; got `T`.