[project @ 1998-04-24 09:48:20 by simonpj]

Fix shadowing in SaAbsInt.lhs

diff --git a/ghc/compiler/stranal/SaAbsInt.lhs b/ghc/compiler/stranal/SaAbsInt.lhs
index 534eb5c..3a9ccc9 100644 (file)
--- 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