Fix an old but subtle bug in the Simplifier

[ghc-hetmet.git] / compiler / simplCore / Simplify.lhs

diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs
index 89c5fb1..dbad116 100644 (file)
--- a/compiler/simplCore/Simplify.lhs
+++ b/compiler/simplCore/Simplify.lhs
@@ -1467,7 +1467,7 @@ simplCaseBinder env scrut case_bndr alts
                -- See Note [no-case-of-case]
        = (env, case_bndr)
 
-       | otherwise     -- Failed try [see Note 2 above]
+       | otherwise     -- Failed try; see Note [Suppressing the case binder-swap]
                        --     not (isEvaldUnfolding (idUnfolding v))
        = case scrut of
            Var v -> (modifyInScope env1 v case_bndr', case_bndr')
@@ -1545,7 +1545,7 @@ simplAlts env scrut case_bndr alts cont'
     do { let alt_env = zapFloats env
        ; (alt_env, scrut', case_bndr') <- simplCaseBinder alt_env scrut case_bndr alts
 
-       ; (imposs_deflt_cons, in_alts) <- prepareAlts scrut case_bndr' alts
+       ; (imposs_deflt_cons, in_alts) <- prepareAlts alt_env scrut case_bndr' alts
 
        ; alts' <- mapM (simplAlt alt_env imposs_deflt_cons case_bndr' cont') in_alts
        ; return (scrut', case_bndr', alts') }