-alt/error_virtual_type2_alt5.nit:38,23: Redef Error: expected `Comparable` for return type; got `T`.
-alt/error_virtual_type2_alt5.nit:40,17--26: Redef Error: expected `null` bound type; got `G[Discrete]`.
-alt/error_virtual_type2_alt5.nit:42,23: Redef Error: expected `Comparable` for return type; got `T`.