I have rebased a patch onto HEAD, and I'm getting this Reading interface for ghc-internal:GHC.Exception.Type; reason: Need decl for SomeException ...not found updating EPS /home/simonpj/code/HEAD-12/_build/stage1/inplace/../libraries/ghc-internal/build/GHC/Err.hi Declaration for errorWithoutStackTrace Unfolding of errorWithoutStackTrace: SomeException ErrorWithoutFlag Failed to load interface for ‘GHC.Exception.Type’. There are files missing in the ‘ghc-internal-0.1.0.0’ package, try running 'ghc-pkg check'. Use -v to see a list of the files searched for. forkM failed: Unfolding of errorWithoutStackTrace IOEnv failure } ending fork (badly) Unfolding of errorWithoutStackTrace Cannot continue after interface file error Does anyone have any idea what is going on? I have made no changes to GHC.Err or exceptions etc. Thanks Simon