I'm also wondering how you configure ghc and ghc-pkg to look in this alternate location for the user package db, and if that carries over to what cabal sees when it calls ghc-pkg.
I'm using a wrapper script around ghc-pkg which sets the proper paths.
So to see if we're getting the same views I think we should add some debugging printing into this function:
Here's the gory details when running setup with -v3 and added debug: <snip> Reading installed packages... ("../../../release/bin/ghc-pkg",["list"]) "========================" /usr/lib/ghc-6.8.3/package.conf: Cabal-1.2.4.0, Cabal-1.6.0.1, HUnit-1.2.0.0, array-0.1.0.0, base-3.0.2.0, binary-0.4.4, bytestring-0.9.0.1.1, containers-0.1.0.2, directory-1.0.0.1, filepath-1.1.0.0, (ghc-6.8.3), haskell98-1.0.1.0, hpc-0.5.0.1, html-1.0.1.1, mtl-1.1.0.2, old-locale-1.0.0.0, old-time-1.0.0.0, packedstring-0.1.0.0, parsec-2.1.0.0, pretty-1.0.0.0, process-1.0.0.1, random-1.0.0.0, readline-1.0.1.0, regex-base-0.93.1, regex-compat-0.92, regex-posix-0.93.2, rts-1.0, template-haskell-2.2.0.0, time-1.1.2.0, unix-2.3.0.1 /home/lars/dev/mhailist/release/package.conf: binary-0.4.2, dlist-0.4.1 "========================" ["/usr/lib/ghc-6.8.3/package.conf","/home/lars/dev/mhailist/release/package.conf"] Just "/usr/lib/ghc-6.8.3/package.conf" Just "/home/lars/dev/mhailist/release/package.conf" Setup.hs: At least the following dependencies are missing: dlist >=0.2 It seems that despite calling the right thing and getting the right stuff it doesn't find it :( Lars