/Users/averyrobinson/Library/Haskell/ghc-7.0.3/lib/hlint-1.8.18/bin
in your path?
Probably not, that directory was likely only created when hlint was first
installed.
That's an odd configuration for cabal to create a new directory for an
executable to install in.
Yes, but Haskell Platform cabal on OS X does that sometimes (I haven't figured out the logic behind when it does so and when it uses ~/Library/Haskell/bin --- note, *not* ~/.cabal/bin, H-P changed the paths for OS X), but I also haven't tried very hard to figure it out.