From 1a6c51c06ff7abf0609612b96222bc4b94ce8d42 Mon Sep 17 00:00:00 2001
From: simonpj <unknown>
Date: Fri, 24 Apr 1998 09:48:20 +0000
Subject: [PATCH] [project @ 1998-04-24 09:48:20 by simonpj] Fix shadowing in
 SaAbsInt.lhs

---
 ghc/compiler/stranal/SaAbsInt.lhs |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/ghc/compiler/stranal/SaAbsInt.lhs b/ghc/compiler/stranal/SaAbsInt.lhs
index 534eb5c..3a9ccc9 100644
--- a/ghc/compiler/stranal/SaAbsInt.lhs
+++ b/ghc/compiler/stranal/SaAbsInt.lhs
@@ -537,8 +537,8 @@ absEval anal (Case expr (PrimAlts alts deflt)) env
   = let
 	expr_val    = absEval anal expr env
 	abs_alts    = [ absEval anal rhs env | (_, rhs) <- alts ]
-			-- Don't bother to extend envt, because unbound vars
-			-- default to the conservative AbsTop
+			-- PrimAlts don't bind anything, so no need
+			-- to extend the environment
 
 	abs_deflt   = absEvalDefault anal expr_val deflt env
     in
@@ -629,8 +629,12 @@ absEvalAlgAlt anal other_scrutinee (con, args, rhs) env
 	-- (If the scrutinee is Top we'll never evaluated this function
 	-- call anyway!)
     ASSERT(ok_scrutinee)
-    absEval anal rhs env
+    absEval anal rhs rhs_env
   where
+    rhs_env = growAbsValEnvList env (args `zip` repeat AbsTop)
+		-- We must extend the environment, because
+		-- there might be shadowing
+
     ok_scrutinee
       = case other_scrutinee of {
 	  AbsTop -> True;   -- i.e., OK
-- 
1.7.10.4