Require a bang pattern when unlifted types are where/let bound; #3182

[ghc-hetmet.git] / compiler / typecheck / TcBinds.lhs

diff --git a/compiler/typecheck/TcBinds.lhs b/compiler/typecheck/TcBinds.lhs
index b4c0d1a..59cd315 100644 (file)
--- a/compiler/typecheck/TcBinds.lhs
+++ b/compiler/typecheck/TcBinds.lhs
@@ -98,7 +98,7 @@ tcHsBootSigs :: HsValBinds Name -> TcM [Id]
 -- signatures in it.  The renamer checked all this
 tcHsBootSigs (ValBindsOut binds sigs)
   = do  { checkTc (null binds) badBootDeclErr
-        ; mapM (addLocM tc_boot_sig) (filter isVanillaLSig sigs) }
+        ; mapM (addLocM tc_boot_sig) (filter isTypeLSig sigs) }
   where
     tc_boot_sig (TypeSig (L _ name) ty)
       = do { sigma_ty <- tcHsSigType (FunSigCtxt name) ty
@@ -151,7 +151,7 @@ tcValBinds _ (ValBindsIn binds _) _
 tcValBinds top_lvl (ValBindsOut binds sigs) thing_inside
   = do  {       -- Typecheck the signature
         ; let { prag_fn = mkPragFun sigs
-              ; ty_sigs = filter isVanillaLSig sigs
+              ; ty_sigs = filter isTypeLSig sigs
               ; sig_fn  = mkTcSigFun ty_sigs }
 
         ; poly_ids <- checkNoErrs (mapAndRecoverM tcTySig ty_sigs)
@@ -428,8 +428,7 @@ tcPrag :: TcId -> Sig Name -> TcM Prag
 tcPrag poly_id (SpecSig _ hs_ty inl) = tcSpecPrag poly_id hs_ty inl
 tcPrag poly_id (SpecInstSig hs_ty)   = tcSpecPrag poly_id hs_ty defaultInlineSpec
 tcPrag _       (InlineSig _ inl)     = return (InlinePrag inl)
-tcPrag _       (FixSig {})           = panic "tcPrag FixSig"
-tcPrag _       (TypeSig {})          = panic "tcPrag TypeSig"
+tcPrag _       sig                  = pprPanic "tcPrag" (ppr sig)
 
 
 tcSpecPrag :: TcId -> LHsType Name -> InlineSpec -> TcM Prag
@@ -476,6 +475,11 @@ checkStrictBinds top_lvl rec_group mbind mono_tys infos
                   (strictBindErr "Recursive" unlifted mbind)
         ; checkTc (isSingletonBag mbind)
                   (strictBindErr "Multiple" unlifted mbind) 
+        -- This should be a checkTc, not a warnTc, but as of GHC 6.11
+        -- the versions of alex and happy available have non-conforming
+        -- templates, so the GHC build fails if it's an error:
+        ; warnTc (not bang_pat)
+                 (unliftedMustBeBang mbind)
         ; mapM_ check_sig infos
         ; return True }
   | otherwise
@@ -487,6 +491,11 @@ checkStrictBinds top_lvl rec_group mbind mono_tys infos
                                          (badStrictSig unlifted sig)
     check_sig _                = return ()
 
+unliftedMustBeBang :: LHsBindsLR Var Var -> SDoc
+unliftedMustBeBang mbind
+  = hang (text "Bindings containing unlifted types must use an outermost bang pattern:")
+         4 (pprLHsBinds mbind)
+
 strictBindErr :: String -> Bool -> LHsBindsLR Var Var -> SDoc
 strictBindErr flavour unlifted mbind
   = hang (text flavour <+> msg <+> ptext (sLit "aren't allowed:")) 
@@ -813,7 +822,7 @@ unifyCtxts (sig1 : sigs)        -- Argument is always non-empty
                -- where F is a type function and (F a ~ [a])
                -- Then unification might succeed with a coercion.  But it's much
                -- much simpler to require that such signatures have identical contexts
-               checkTc (all isIdentityCoercion cois)
+               checkTc (all isIdentityCoI cois)
                        (ptext (sLit "Mutually dependent functions have syntactically distinct contexts"))
              }
 
@@ -1045,8 +1054,10 @@ mkTcSigFun :: [LSig Name] -> TcSigFun
 -- Precondition: no duplicates
 mkTcSigFun sigs = lookupNameEnv env
   where
-    env = mkNameEnv [(name, hsExplicitTvs lhs_ty)
-                    | L _ (TypeSig (L _ name) lhs_ty) <- sigs]
+    env = mkNameEnv (mapCatMaybes mk_pair sigs)
+    mk_pair (L _ (TypeSig (L _ name) lhs_ty)) = Just (name, hsExplicitTvs lhs_ty)
+    mk_pair (L _ (IdSig id))                  = Just (idName id, [])
+    mk_pair _                                 = Nothing    
         -- The scoped names are the ones explicitly mentioned
         -- in the HsForAll.  (There may be more in sigma_ty, because
         -- of nested type synonyms.  See Note [More instantiated than scoped].)
@@ -1100,6 +1111,8 @@ tcTySig (L span (TypeSig (L _ name) ty))
   = setSrcSpan span             $
     do  { sigma_ty <- tcHsSigType (FunSigCtxt name) ty
         ; return (mkLocalId name sigma_ty) }
+tcTySig (L _ (IdSig id))
+  = return id
 tcTySig s = pprPanic "tcTySig" (ppr s)
 
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