RE: GHCI Can't Find Module But GHC Can

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Aha! GHCi (and ghc --make) has a pre-pass that looks through the file for import declarations so it can build the dependency tree, and it does this without using a proper Haskell parser. I'll bet it's ignoring the CPP directives. Probably it should flag an error, I'll look into it.

Using an improper parser sounds a little delicate.

Yes, it is - I've never really been happy with the way we do that. Sigh, another thing for the TODO list.... Cheers, Simon