Support for -fwarn-unused-do-bind and -fwarn-wrong-do-bind, as per #3263

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

diff --git a/compiler/typecheck/TcBinds.lhs b/compiler/typecheck/TcBinds.lhs
index 59ae266..eae66a8 100644 (file)
--- a/compiler/typecheck/TcBinds.lhs
+++ b/compiler/typecheck/TcBinds.lhs
@@ -475,6 +475,12 @@ 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:
+        ; warnUnlifted <- doptM Opt_WarnLazyUnliftedBindings
+        ; warnTc (warnUnlifted && not bang_pat)
+                 (unliftedMustBeBang mbind)
         ; mapM_ check_sig infos
         ; return True }
   | otherwise
@@ -486,6 +492,12 @@ 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)
+ $$ text "*** This will be an error in GHC 6.14! Fix your code now!"
+
 strictBindErr :: String -> Bool -> LHsBindsLR Var Var -> SDoc
 strictBindErr flavour unlifted mbind
   = hang (text flavour <+> msg <+> ptext (sLit "aren't allowed:")) 
@@ -724,7 +736,7 @@ generalise :: DynFlags -> TopLevelFlag
 -- The returned [TyVar] are all ready to quantify
 
 generalise dflags top_lvl bind_list sig_fn mono_infos lie_req
-  | isMonoGroup dflags bind_list
+  | isMonoGroup dflags top_lvl bind_list sigs
   = do  { extendLIEs lie_req
         ; return ([], [], emptyBag) }
 
@@ -795,7 +807,7 @@ unifyCtxts :: [TcSigInfo] -> TcM [Inst]
 -- Post-condition: the returned Insts are full zonked
 unifyCtxts [] = panic "unifyCtxts []"
 unifyCtxts (sig1 : sigs)        -- Argument is always non-empty
-  = do  { mapM unify_ctxt sigs
+  = do  { mapM_ unify_ctxt sigs
         ; theta <- zonkTcThetaType (sig_theta sig1)
         ; newDictBndrs (sig_loc sig1) theta }
   where
@@ -854,7 +866,7 @@ checkDistinctTyVars :: [TcTyVar] -> TcM [TcTyVar]
 
 checkDistinctTyVars sig_tvs
   = do  { zonked_tvs <- mapM zonkSigTyVar sig_tvs
-        ; foldlM check_dup emptyVarEnv (sig_tvs `zip` zonked_tvs)
+        ; foldlM_ check_dup emptyVarEnv (sig_tvs `zip` zonked_tvs)
         ; return zonked_tvs }
   where
     check_dup :: TyVarEnv TcTyVar -> (TcTyVar, TcTyVar) -> TcM (TyVarEnv TcTyVar)
@@ -1147,10 +1159,12 @@ tcInstSig use_skols name
                               sig_loc = loc }) }
 
 -------------------
-isMonoGroup :: DynFlags -> [LHsBind Name] -> Bool
+isMonoGroup :: DynFlags -> TopLevelFlag -> [LHsBind Name]
+            -> [TcSigInfo] ->  Bool
 -- No generalisation at all
-isMonoGroup dflags binds
-  = dopt Opt_MonoPatBinds dflags && any is_pat_bind binds
+isMonoGroup dflags top_lvl binds sigs
+  =  (dopt Opt_MonoPatBinds dflags && any is_pat_bind binds)
+  || (dopt Opt_MonoLocalBinds dflags && null sigs && not (isTopLevel top_lvl))
   where
     is_pat_bind (L _ (PatBind {})) = True
     is_pat_bind _                  = False