rnfail040.hs:7:12:
    Conflicting exports for ‘nub’:
       ‘module M’ exports ‘M.nub’
         imported from ‘Data.List’ at rnfail040.hs:10:2-22
       ‘module M’ exports ‘T.nub’
         imported from ‘Rnfail040_A’ at rnfail040.hs:11:2-24
         (and originally defined at Rnfail040_A.hs:2:3-5)