From 3d638f1b7b665c0e67e4e20827ad98cf307ff381 Mon Sep 17 00:00:00 2001
From: "simonpj@microsoft.com" <unknown>
Date: Thu, 23 Apr 2009 09:42:37 +0000
Subject: [PATCH] Fix Trac #3176: intercept naughty record selectors

When making record selectors into ordinary functions (rather than
magial implicit Ids) I forgot that they could therefore show up in
the *local* TcEnv, not the global one.  This fixes that problem,
and thereby Trac #3176.
---
 compiler/typecheck/TcExpr.lhs |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/compiler/typecheck/TcExpr.lhs b/compiler/typecheck/TcExpr.lhs
index 51d6f4b..b255fdb 100644
--- a/compiler/typecheck/TcExpr.lhs
+++ b/compiler/typecheck/TcExpr.lhs
@@ -1069,6 +1069,9 @@ lookupFun orig id_name
 	    	-- nor does it need the 'lifting' treatment
 
     	    ATcId { tct_id = id, tct_type = ty, tct_co = mb_co, tct_level = lvl }
+	    	| isNaughtyRecordSelector id -> failWithTc (naughtyRecordSel id)
+		  			  -- Note [Local record selectors]
+		| otherwise
 		-> do { thLocalId orig id ty lvl
 		      ; case mb_co of
 			  Unrefineable    -> return (HsVar id, ty)
@@ -1147,6 +1150,12 @@ thBrackId orig id ps_var lie_var
 #endif /* GHCI */
 \end{code}
 
+Local record selectors
+~~~~~~~~~~~~~~~~~~~~~~
+Record selectors for TyCons in this module are ordinary local bindings,
+which show up as ATcIds rather than AGlobals.  So we need to check for
+naughtiness in both branches.  c.f. TcTyClsBindings.mkAuxBinds.
+
 
 %************************************************************************
 %*									*
-- 
1.7.10.4