Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : master
http://hackage.haskell.org/trac/ghc/changeset/c6b0fd62fc715aa6c666eb8afe09073ac7b87a83 >--------------------------------------------------------------- commit c6b0fd62fc715aa6c666eb8afe09073ac7b87a83 Author: Simon Marlow <[email protected]> Date: Thu Nov 24 14:04:23 2011 +0000 Relax the restriction on using abstract newtypes in FFI declarations. Given the high impact of this change, we decided to back off and make abstract newtypes give a warning for one release, before we make it an error in 7.6.1. Codec/Compression/Zlib/Stream.hsc:884:1: Warning: newtype `CInt' is used in an FFI declaration, but its constructor is not in scope. This will become an error in GHC 7.6.1. When checking declaration: foreign import ccall unsafe "static zlib.h deflate" c_deflate :: StreamState -> CInt -> IO CInt >--------------------------------------------------------------- compiler/typecheck/TcForeign.lhs | 22 +++++++++++++++++----- 1 files changed, 17 insertions(+), 5 deletions(-) diff --git a/compiler/typecheck/TcForeign.lhs b/compiler/typecheck/TcForeign.lhs index 886b84d..5a4bf77 100644 --- a/compiler/typecheck/TcForeign.lhs +++ b/compiler/typecheck/TcForeign.lhs @@ -121,17 +121,29 @@ normaliseFfiType' env ty0 = go [] ty0 panic "normaliseFfiType': Got more GREs than expected" _ -> return False - if newtypeOK - then do let nt_co = mkAxInstCo (newTyConCo tc) tys - add_co nt_co rec_nts' nt_rhs - else children_only + when (not newtypeOK) $ + -- later: stop_here + addWarnTc (ptext (sLit "newtype") <+> quotes (ppr tc) <+> + ptext (sLit "is used in an FFI declaration,") $$ + ptext (sLit "but its constructor is not in scope.") $$ + ptext (sLit "This will become an error in GHC 7.6.1.")) + + let nt_co = mkAxInstCo (newTyConCo tc) tys + add_co nt_co rec_nts' nt_rhs + | isFamilyTyCon tc -- Expand open tycons , (co, ty) <- normaliseTcApp env tc tys , not (isReflCo co) = add_co co rec_nts ty + | otherwise - = children_only + = return (mkReflCo ty, ty) + -- If we have reached an ordinary (non-newtype) type constructor, + -- we are done. Note that we don't need to normalise the arguments, + -- because whether an FFI type is legal or not depends only on + -- the top-level type constructor (e.g. "Ptr a" is valid for all a). where + children_only = do xs <- mapM (go rec_nts) tys let (cos, tys') = unzip xs return (mkTyConAppCo tc cos, mkTyConApp tc tys') _______________________________________________ Cvs-ghc mailing list [email protected] http://www.haskell.org/mailman/listinfo/cvs-ghc
