Installation of Alex in the msys2 i686 instructions is broken, more details in https://ghc.haskell.org/trac/ghc/ticket/9712. Before I spend more time on this, maybe someone knows off the bat what's going on? $ cabal install alex Resolving dependencies... Downloading primitive-0.5.4.0... Configuring primitive-0.5.4.0... Failed to install primitive-0.5.4.0 Build log ( C:\Users\Gintas\AppData\Roaming\cabal\logs\primitive-0.5.4.0.log ): [1 of 1] Compiling Main ( C:\Users\Gintas\Downloads\msys32\tmp\primitive-0.5.4.0-2404\primitive-0.5.4.0\dist\setup\setup.hs, C:\Users\Gintas\Downloads\msys32\tmp\primitive-0.5.4.0-2404\primitive-0.5.4.0\dist\setup\Main.o ) Linking C:\Users\Gintas\Downloads\msys32\tmp\primitive-0.5.4.0-2404\primitive-0.5.4.0\dist\setup\setup.exe ... Configuring primitive-0.5.4.0... setup-Simple-Cabal-1.18.1.3-i386-windows-ghc-7.8.3.exe: Missing dependency on a foreign library: * Missing (or bad) header file: primitive-memops.h This problem can usually be solved by installing the system package that provides this library (you may need the "-dev" version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is. If the header file does exist, it may contain errors that are caught by the C compiler at the preprocessing stage. In this case you can re-run configure with the verbosity flag -v3 to see the error messages. -- Gintautas Miliauskas