Tidy up the treatment of dead binders

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

diff --git a/compiler/simplCore/LiberateCase.lhs b/compiler/simplCore/LiberateCase.lhs
index 9c51103..9fe6b87 100644 (file)
--- a/compiler/simplCore/LiberateCase.lhs
+++ b/compiler/simplCore/LiberateCase.lhs
@@ -4,13 +4,6 @@
 \section[LiberateCase]{Unroll recursion to allow evals to be lifted from a loop}
 
 \begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
 module LiberateCase ( liberateCase ) where
 
 #include "HsVersions.h"
@@ -25,7 +18,6 @@ import UniqSupply     ( UniqSupply )
 import SimplMonad      ( SimplCount, zeroSimplCount )
 import Id
 import VarEnv
-import Name            ( localiseName )
 import Util             ( notNull )
 \end{code}
 
@@ -142,7 +134,7 @@ liberateCase hsc_env _ _ guts
                        {- no specific flag for dumping -} 
        ; return (zeroSimplCount dflags, guts { mg_binds = binds' }) }
   where
-    do_prog env [] = []
+    do_prog _   [] = []
     do_prog env (bind:binds) = bind' : do_prog env' binds
                             where
                               (env', bind') = libCaseBind env bind
@@ -166,7 +158,7 @@ libCaseBind env (NonRec binder rhs)
 libCaseBind env (Rec pairs)
   = (env_body, Rec pairs')
   where
-    (binders, rhss) = unzip pairs
+    (binders, _rhss) = unzip pairs
 
     env_body = addBinders env binders
 
@@ -178,10 +170,10 @@ libCaseBind env (Rec pairs)
        -- processing the rhs with an *un-extended* environment, so
        -- that the same process doesn't occur for ever!
        --
-    extended_env = addRecBinds env [ (adjust binder, libCase env_body rhs)
+    extended_env = addRecBinds env [ (localiseId binder, libCase env_body rhs)
                                   | (binder, rhs) <- pairs ]
 
-       -- Two subtle things: 
+       -- The call to localiseId is needed for two subtle reasons
        -- (a)  Reset the export flags on the binders so
        --      that we don't get name clashes on exported things if the 
        --      local binding floats out to top level.  This is most unlikely
@@ -191,7 +183,6 @@ libCaseBind env (Rec pairs)
        -- (b)  Make the name an Internal one.  External Names should never be
        --      nested; if it were floated to the top level, we'd get a name
        --      clash at code generation time.
-    adjust bndr = setIdNotExported (setIdName bndr (localiseName (idName bndr)))
 
     rhs_small_enough (id,rhs)
        =  idArity id > 0       -- Note [Only functions!]
@@ -208,9 +199,9 @@ libCase :: LibCaseEnv
        -> CoreExpr
        -> CoreExpr
 
-libCase env (Var v)            = libCaseId env v
-libCase env (Lit lit)          = Lit lit
-libCase env (Type ty)          = Type ty
+libCase env (Var v)             = libCaseId env v
+libCase _   (Lit lit)           = Lit lit
+libCase _   (Type ty)           = Type ty
 libCase env (App fun arg)       = App (libCase env fun) (libCase env arg)
 libCase env (Note note body)    = Note note (libCase env body)
 libCase env (Cast e co)         = Cast (libCase env e) co
@@ -229,8 +220,10 @@ libCase env (Case scrut bndr ty alts)
     env_alts = addBinders (mk_alt_env scrut) [bndr]
     mk_alt_env (Var scrut_var) = addScrutedVar env scrut_var
     mk_alt_env (Cast scrut _)  = mk_alt_env scrut      -- Note [Scrutinee with cast]
-    mk_alt_env otehr          = env
+    mk_alt_env _              = env
 
+libCaseAlt :: LibCaseEnv -> (AltCon, [CoreBndr], CoreExpr)
+                         -> (AltCon, [CoreBndr], CoreExpr)
 libCaseAlt env (con,args,rhs) = (con, args, libCase (addBinders env args) rhs)
 \end{code}
 
@@ -384,6 +377,7 @@ initEnv dflags
                 lc_rec_env = emptyVarEnv,
                 lc_scruts = [] }
 
+bombOutSize :: LibCaseEnv -> Maybe Int
 bombOutSize = lc_size
 \end{code}