errors with ssh and lts-8.21

gistfile1.txt

[9 of 9] Compiling SSH              ( src/SSH.hs, .stack-work/dist/i386-linux/Cabal-1.24.2.0/build/SSH.o )                                                    
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:12:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘CryptoRandomGen, genBytes, genSeedLength’                                                                                                  
    from module ‘Crypto.Random’ is redundant                                                                                                                  
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:13:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘Crypto.Types’ is redundant                                                                                                                 
      except perhaps to import instances from ‘Crypto.Types’                                                                                                  
    To import instances alone, use: import Crypto.Types()                                                                                                     
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:15:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘Test.QuickCheck’ is redundant                                                                                                              
      except perhaps to import instances from ‘Test.QuickCheck’                                                                                               
    To import instances alone, use: import Test.QuickCheck()                                                                                                  
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:20:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘OpenSSL.BN’ is redundant                                                                                                                   
      except perhaps to import instances from ‘OpenSSL.BN’                                                                                                    
    To import instances alone, use: import OpenSSL.BN()                                                                                                       
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:24:1: warning: [-Wunused-imports]                                                                                     
    The qualified import of ‘Data.ByteString’ is redundant                                                                                                    
      except perhaps to import instances from ‘Data.ByteString’                                                                                               
    To import instances alone, use: import Data.ByteString()                                                                                                  
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:25:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘Data.Tagged’ is redundant                                                                                                                  
      except perhaps to import instances from ‘Data.Tagged’                                                                                                   
    To import instances alone, use: import Data.Tagged()                                                                                                      
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:30:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘generator, safePrime’                                                                                                                      
    from module ‘SSH.Crypto’ is redundant                                                                                                                     
                                                                                                                                                              
/home/simon/src/ssh_darcshub/src/SSH.hs:35:1: warning: [-Wunused-imports]                                                                                     
    The import of ‘readInteger’                                                                                                                               
    from module ‘SSH.NetReader’ is redundant