alt/error_type_unk_alt6.nit:19,10--13: Error: class `Fail` not found in module `error_type_unk_alt6`.
alt/error_type_unk_alt6.nit:22,17--20: Error: class `Fail` not found in module `error_type_unk_alt6`.
alt/error_type_unk_alt6.nit:23,9: Error: method `+` does not exists in `Bool`.