PS C:\WINDOWS\system32> ghciGHCi, version 8.4.3: http://www.haskell.org/ghc/ :? for helpghc.exe: C:\F\G77\lib\libmingw32.a: Not a x86_64 PE+ file.ghc.exe: getNumberOfSymbols: error whilst reading `CRTglob.o' header in `C:\F\G77\lib\libmingw32.a': Unknown COFF_OBJ_TYPE.ghc.exe: loadArchive: error whilst reading `C:\F\G77\lib\libmingw32.a'ghc.exe: panic! (the 'impossible' happened) (GHC version 8.4.3 for x86_64-unknown-mingw32): loadArchive "C:\\F\\G77\\lib\\libmingw32.a": failedPlease report this as a GHC bug: http://www.haskell.org/ghc/reportabug