From: simonpj@microsoft.com <unknown>
Date: Thu, 2 Sep 2010 23:32:27 +0000 (+0000)
Subject: Remove checkFreeness; no longer needed
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=361475818720689fb0a83fffd0138d1363da8b70;p=ghc-hetmet.git

Remove checkFreeness; no longer needed
---

diff --git a/compiler/typecheck/TcMType.lhs b/compiler/typecheck/TcMType.lhs
index 243fc85..4d6ced3 100644
--- a/compiler/typecheck/TcMType.lhs
+++ b/compiler/typecheck/TcMType.lhs
@@ -40,7 +40,7 @@ module TcMType (
   --------------------------------
   -- Checking type validity
   Rank, UserTypeCtxt(..), checkValidType, checkValidMonoType,
-  SourceTyCtxt(..), checkValidTheta, checkFreeness,
+  SourceTyCtxt(..), checkValidTheta, 
   checkValidInstHead, checkValidInstance, 
   checkInstTermination, checkValidTypeInst, checkTyFamFreeness, checkKinds,
   checkUpdateMeta, updateMeta, checkTauTvUpdate, fillBoxWithTau, unifyKindCtxt,
@@ -1136,7 +1136,6 @@ check_type rank ubx_tup ty
 		-- with a decent error message
 	; check_valid_theta SigmaCtxt theta
 	; check_type rank ubx_tup tau	-- Allow foralls to right of arrow
-	; checkFreeness tvs theta
 	; checkAmbiguity tvs theta (tyVarsOfType tau) }
   where
     (tvs, theta, tau) = tcSplitSigmaTy ty
@@ -1490,28 +1489,6 @@ in each constraint is in V.  So we disallow a type like
 even in a scope where b is in scope.
 
 \begin{code}
-checkFreeness :: [Var] -> [PredType] -> TcM ()
-checkFreeness forall_tyvars theta
-  = do	{ flexible_contexts <- doptM Opt_FlexibleContexts
-	; unless flexible_contexts $ mapM_ complain (filter is_free theta) }
-  where    
-    is_free pred     =  not (isIPPred pred)
-		     && not (any bound_var (varSetElems (tyVarsOfPred pred)))
-    bound_var ct_var = ct_var `elem` forall_tyvars
-    complain pred    = addErrTc (freeErr pred)
-
-freeErr :: PredType -> SDoc
-freeErr pred
-  = sep [ ptext (sLit "All of the type variables in the constraint") <+> 
-          quotes (pprPred pred)
-	, ptext (sLit "are already in scope") <+>
-          ptext (sLit "(at least one must be universally quantified here)")
-	, nest 4 $
-            ptext (sLit "(Use -XFlexibleContexts to lift this restriction)")
-        ]
-\end{code}
-
-\begin{code}
 checkThetaCtxt :: SourceTyCtxt -> ThetaType -> SDoc
 checkThetaCtxt ctxt theta
   = vcat [ptext (sLit "In the context:") <+> pprTheta theta,