I've spent much of the day trying to determine the root cause of, ... "inplace/bin/ghc-cabal" register libraries/ghc-prim dist-install "/opt/exp/ghc/root-ghc-llvm-dyn-7.8/lib/ghc-7.7.20131214/bin/ghc" "/opt/exp/ghc/root-ghc-llvm-dyn-7.8/lib/ghc-7.7.20131214/bin/ghc-pkg" "/opt/exp/ghc/root-ghc-llvm-dyn-7.8/lib/ghc-7.7.20131214" '' '/opt/exp/ghc/root-ghc-llvm-dyn-7.8' '/opt/exp/ghc/root-ghc-llvm-dyn-7.8/lib/ghc-7.7.20131214' '/opt/exp/ghc/root-ghc-llvm-dyn-7.8/share/doc/ghc/html/libraries' NO ghc-cabal: Bad interface file: dist-install/build/GHC/CString.hi mismatched interface file ways (wanted "dyn", got "") I'm attempting to produce a build to validate dynamic linking with LLVM so build.mk looks something like, DYNAMIC_BY_DEFAULT = YES BuildFlavour = quick-llvm Looking at the interface files produced for ghc-prim, it seems that ghc-cabal is looking for the wrong extension, $ inplace/bin/ghc-stage2 --show-iface libraries/ghc-prim/dist-install/build/GHC/CString.hi | grep --after-context=1 Way Way: Wanted [d, y, n], got [] $ inplace/bin/ghc-stage2 --show-iface libraries/ghc-prim/dist-install/build/GHC/CString.dyn_hi | grep --after-context=1 Way Way: Wanted [d, y, n], got [d, y, n] Any ideas what might be going on here? How is `ghc-cabal` supposed to know which interface file to use? Cheers, - Ben