In a larger project I use qualified imports a lot. Now, when I try to compile the program with nhc98 I get ... ... nhc98 -98 -I/home/ralf/Haskell/LibRH/nhc98/ -P/home/ralf/Haskell/LibRH/nhc98/ -c -o Future.o Future.lhs Warning: when renaming newtype of imported newtype: Real type of OrdUniqListFM.FM is not visible. I might get boxed/unboxed info wrong. nhc98 -98 -I/home/ralf/Haskell/LibRH/nhc98/ -P/home/ralf/Haskell/LibRH/nhc98/ -c -o LR0.o LR0.lhs ==================================== Error when renaming:: Identifier unionMany defined 3 times. Identifier fromList defined 3 times. Identifier lookup defined 2 times. Identifier union defined 3 times. Identifier elem defined 2 times. Identifier length defined 3 times. This is basically true. However, the definitions reside in different modules that are imported qualified. Unfortunately, I wasn't able to boil down the error (all the toy programs I came up with work fine). I'll send you the files, if you have time to chase down the bug. Cheers, Ralf