From f5c113de54455bc1320da4674c70e17598832533 Mon Sep 17 00:00:00 2001
From: Duncan Coutts <duncan@well-typed.com>
Date: Thu, 11 Jun 2009 20:26:47 +0000
Subject: [PATCH] Require GHCForeignImportPrim for "foreign import prim" In
 practise currently you also need UnliftedFFITypes, however
 the restriction to just unlifted types may be lifted in
 future.

---
 compiler/main/DynFlags.hs        |    2 ++
 compiler/typecheck/TcForeign.lhs |    4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index d8b2e78..f4971cd 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -203,6 +203,7 @@ data DynFlag
    | Opt_ExtendedDefaultRules           -- Use GHC's extended rules for defaulting
    | Opt_ForeignFunctionInterface
    | Opt_UnliftedFFITypes
+   | Opt_GHCForeignImportPrim
    | Opt_PArr                           -- Syntactic support for parallel arrays
    | Opt_Arrows                         -- Arrow-notation syntax
    | Opt_TemplateHaskell
@@ -1759,6 +1760,7 @@ xFlags = [
   ( "TransformListComp",                Opt_TransformListComp, const Supported ),
   ( "ForeignFunctionInterface",         Opt_ForeignFunctionInterface, const Supported ),
   ( "UnliftedFFITypes",                 Opt_UnliftedFFITypes, const Supported ),
+  ( "GHCForeignImportPrim",             Opt_GHCForeignImportPrim, const Supported ),
   ( "LiberalTypeSynonyms",              Opt_LiberalTypeSynonyms, const Supported ),
   ( "Rank2Types",                       Opt_Rank2Types, const Supported ),
   ( "RankNTypes",                       Opt_RankNTypes, const Supported ),
diff --git a/compiler/typecheck/TcForeign.lhs b/compiler/typecheck/TcForeign.lhs
index 1a8a3f3..52b1ec6 100644
--- a/compiler/typecheck/TcForeign.lhs
+++ b/compiler/typecheck/TcForeign.lhs
@@ -152,11 +152,13 @@ tcCheckFIType sig_ty arg_tys res_ty idecl@(CImport cconv safety _ _ (CFunction t
           checkForeignRes nonIOok (isFFIImportResultTy dflags) res_ty
           return idecl
   | cconv == PrimCallConv = do
+      dflags <- getDOpts
+      check (dopt Opt_GHCForeignImportPrim dflags)
+            (text "Use -XGHCForeignImportPrim to allow `foreign import prim'.")
       checkCg (checkCOrAsmOrDotNetOrInterp)
       checkCTarget target
       check (playSafe safety)
             (text "The safe/unsafe annotation should not be used with `foreign import prim'.")
-      dflags <- getDOpts
       checkForeignArgs (isFFIPrimArgumentTy dflags) arg_tys
       -- prim import result is more liberal, allows (#,,#)
       checkForeignRes nonIOok (isFFIPrimResultTy dflags) res_ty
-- 
1.7.10.4