Hi all, I'm currently going through this torturous process and I'm hoping that someone here will be able to help. I'm making changes in the codegen. My changes are currently buggy, and I need a working stage 1 compiler to be able to debug. Basically I need to build libraries using the branch my changes are based on, then build stage 1 with my branch, so that I'll be able to build and run programs using stage 1 that uses my codegen changes. The changes are compatible with the old codegen (i.e. no changes in calling conventions or anything like that) so this should work. Normally I do this $ git checkout master $ git distclean && ./boot && ./configure && make $ git checkout my_branch $ cd compiler; make 1 This gives me stage 1 compiler that uses my buggy codegen changes, plus libraries built with the old and correct codegen. However the problem is I'm also adding a new file in my_branch, and the build system just doesn't register that fact, even after adding the line I added to compiler/ghc.cabal.in to compiler/ghc.cabal. So far the only way to fix this that I could find was to run ./configure again, then run make for a few seconds at the top level, then do `make 1` in compiler/. Unfortunately even that doesn't work when the master branch and my_branch have different dates, because `make` in master branch produces a different version than the `make` in my_branch, so the interface files become incompatible. Anyone have any ideas on how to proceed here? Thanks, Ömer