Excerpts from Peter Verswyvelen's message of Wed Jan 09 10:07:46 -0600 2008:
Is my code incorrect, or is this a (known?) bug in GHC 6.8.2 on Windows? I haven't tried the Linux version yet.
The same thing happens on my Windows XP box as it does with yours. On both windows and my linux box, ghc --make works fine, and on linux with ghci, it works fine but not on windows (and fails with the exact same error.) Just from a general idea I would say that the reason would be related to the linker loading base twice: once when ghci itself is started, and the second time when you actually call into the ghc api; setSessionDynFlags will give your session knowledge of all installed packages, so when you're actually executing code using runStmt it may reload the object file into an address space where it already resides. GHCi only has one symbol table in its address space, so loading twice will naturally cause clashes. This seems slightly related to the fact that, you can't do similar with hs-plugins as it directly interfaces with the runtime linker and therefore you must always compile your apps that use hs-plugins rather than loading them into ghci. Why this would only occur on Windows and not linux though, I have no idea. It seems a bug report is well in order. I'm probably just talking nonsense though; I guess you'll just have to make due with ghc --make! Sorry I couldn't further help, you may get more info by asking a ghc guru. - Austin -- "It was in the days of the rains that their prayers went up, not from the fingering of knotted prayer cords or the spinning of prayer wheels, but from the great pray-machine in the monastery of Ratri, goddess of the Night." Roger Zelazny