Is there any heuristic in GHC that discourages putting unfoldings of functions into .hi files if the function occurs on the right handside of a RULES rule? I have code, where this seems to be the case. When I remove the rewrite rule, the function is placed into the .hi file, but with the rewrite rule, it isn't - despite an INLINE pragma for that function! Unfortunately, the example is rather big and I didn't manage to find a small piece of code showing the same behaviour yet. This currently bites me in a rule of the form {-# "" forall ... foo .. bar .. = foobar .. #-} {-# INLINE foobar #-} foobar .. = ... where I want foobar inlined. Cheers, Manuel PS: I do this only because GHC crashes when I place the rhs of the foobar definition directly into the rhs of the rule, but again I don't have a small example producing the bug *sigh*