ghc-5.02.2 is not a cygwin application,
Whilst I was aware that GHC no longer requires Cygwin to run, I didn't realise that it actively discourages use under Cygwin. This issue arose because a Windows user would like to use `hmake' with GHC, and the `hmake' installation currently requires Cygwin. Is there really no possibility of using GHC in the Cygwin environment?
Don't know where you get this "actively discouraging" bit from. You make it sound as if it isn't possible, which certainly isn't the case - you just have to keep in mind that using filepaths that only makes sense wrt. the Cygwin mount table is not a Good Idea, i.e., stuff like /cygdrive/d/foo. (Have a look at the 'cygpath' utility, btw). If you're really that gung-ho about cygwin, you could always compile up GHC using the cygwin toolchain.
Internally, the compiler will canonicalise paths to 'platform-native' formats before passing them to external tools, which is why you see the slashes reversed.
As far as I understand the Windows filesystem (which I admit is not very far at all), \d\foo is not a canonical pathname, so why is GHC generating it?
Because you said /d/foo , which it translated to \d\foo before feeding ut to 'as' (canonical == canonical slashes), which is another non-cygwin application (i.e., we include cygwin-free versions of gcc, as and ld with the ghc installer). --sigbjorn