X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcEnv.lhs;h=1f9d3050eff2fd7094b829ee8ace3e4949b43511;hb=4c6a3f787abcaed009a574196d82237d9ae64fc8;hp=ac55f4b16df5e1c5b6a1062e3bbc4ef87c5cb512;hpb=f014b60bba8432be6f89c0dc99a54988fb4475af;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcEnv.lhs b/compiler/typecheck/TcEnv.lhs
index ac55f4b..1f9d305 100644
--- a/compiler/typecheck/TcEnv.lhs
+++ b/compiler/typecheck/TcEnv.lhs
@@ -35,7 +35,6 @@ module TcEnv(
 	tcLookupId, tcLookupTyVar, getScopedTyVarBinds,
 	lclEnvElts, getInLocalScope, findGlobals, 
 	wrongThingErr, pprBinders,
-	refineEnvironment,
 
 	tcExtendRecEnv,    	-- For knot-tying
 
@@ -61,7 +60,6 @@ import IfaceEnv
 import TcRnMonad
 import TcMType
 import TcType
-import TcGadt
 -- import TcSuspension
 import qualified Type
 import Var
@@ -83,6 +81,7 @@ import HscTypes
 import SrcLoc
 import Outputable
 import Maybes
+import FastString
 \end{code}
 
 
@@ -135,10 +134,22 @@ tcLookupGlobal name
 
 tcLookupField :: Name -> TcM Id		-- Returns the selector Id
 tcLookupField name = do
-    thing <- tcLookupGlobal name
+    thing <- tcLookup name	-- Note [Record field lookup]
     case thing of
-	AnId id -> return id
-	other	-> wrongThingErr "field name" (AGlobal thing) name
+	AGlobal (AnId id) -> return id
+	thing -> wrongThingErr "field name" thing name
+
+{- Note [Record field lookup]
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~
+You might think we should have tcLookupGlobal here, since record fields
+are always top level.  But consider
+	f = e { f = True }
+Then the renamer (which does not keep track of what is a record selector
+and what is not) will rename the definition thus
+	f_7 = e { f_7 = True }
+Now the type checker will find f_7 in the *local* type environment, not
+the global one. It's wrong, of course, but we want to report a tidy
+error, not in TcEnv.notFound.  -}
 
 tcLookupDataCon :: Name -> TcM DataCon
 tcLookupDataCon name = do
@@ -452,38 +463,6 @@ find_thing ignore_it tidy_env (ATyVar tv ty) = do
 find_thing _ _ thing = pprPanic "find_thing" (ppr thing)
 \end{code}
 
-\begin{code}
-refineEnvironment 
-	:: Refinement 
-	-> Bool			-- whether type equations are involved
-	-> TcM a 
-	-> TcM a
--- I don't think I have to refine the set of global type variables in scope
--- Reason: the refinement never increases that set
-refineEnvironment reft otherEquations thing_inside
-  | isEmptyRefinement reft 	-- Common case
-  , not otherEquations
-  = thing_inside
-  | otherwise
-  = do	{ env <- getLclEnv
-	; let le' = mapNameEnv refine (tcl_env env)
- 	; setLclEnv (env {tcl_env = le'}) thing_inside }
-  where
-    refine elt@(ATcId { tct_co = Rigid co, tct_type = ty })
-	| Just (co', ty') <- refineType reft ty
-	= elt { tct_co = Rigid (WpCo co' <.> co), tct_type = ty' }
-    refine elt@(ATcId { tct_co = Wobbly})
--- Main new idea: make wobbly things invisible whenever there 
---		  is a refinement of any sort
---	| otherEquations
-	= elt { tct_co = WobblyInvisible}
-    refine (ATyVar tv ty) 
-	| Just (_, ty') <- refineType reft ty
-	= ATyVar tv ty'	-- Ignore the coercion that refineType returns
-
-    refine elt = elt	-- Common case
-\end{code}
-
 %************************************************************************
 %*									*
 \subsection{The global tyvars}