X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDsArrows.lhs;h=89c453fd7302cc298a31e0dfb7f2f4a7d63c2fd9;hb=707ea5881703d680155aab268bdbf7edc113e3b1;hp=63e5cbef28a9542b82d7b92678d0e1fc5e110095;hpb=34bb2bb9114fe35fc743b67254c6db7c3097dc72;p=ghc-hetmet.git

diff --git a/compiler/deSugar/DsArrows.lhs b/compiler/deSugar/DsArrows.lhs
index 63e5cbe..89c453f 100644
--- a/compiler/deSugar/DsArrows.lhs
+++ b/compiler/deSugar/DsArrows.lhs
@@ -34,13 +34,12 @@ import MkCore
 import Name
 import Var
 import Id
-import PrelInfo
 import DataCon
 import TysWiredIn
 import BasicTypes
 import PrelNames
 import Outputable
-
+import Bag
 import VarSet
 import SrcLoc
 
@@ -405,7 +404,7 @@ dsCmd ids local_vars env_ids stack res_ty (HsPar cmd)
 --			if e then Left ((xs1)*ts) else Right ((xs2)*ts)) >>>
 --		     c1 ||| c2
 
-dsCmd ids local_vars env_ids stack res_ty (HsIf cond then_cmd else_cmd) = do
+dsCmd ids local_vars env_ids stack res_ty (HsIf mb_fun cond then_cmd else_cmd) = do
     core_cond <- dsLExpr cond
     (core_then, fvs_then, then_ids) <- dsfixCmd ids local_vars stack res_ty then_cmd
     (core_else, fvs_else, else_ids) <- dsfixCmd ids local_vars stack res_ty else_cmd
@@ -413,20 +412,26 @@ dsCmd ids local_vars env_ids stack res_ty (HsIf cond then_cmd else_cmd) = do
     either_con <- dsLookupTyCon eitherTyConName
     left_con   <- dsLookupDataCon leftDataConName
     right_con  <- dsLookupDataCon rightDataConName
-    let
-        left_expr ty1 ty2 e = mkConApp left_con [Type ty1, Type ty2, e]
-        right_expr ty1 ty2 e = mkConApp right_con [Type ty1, Type ty2, e]
+
+    let mk_left_expr ty1 ty2 e = mkConApp left_con [Type ty1, Type ty2, e]
+        mk_right_expr ty1 ty2 e = mkConApp right_con [Type ty1, Type ty2, e]
 
         in_ty = envStackType env_ids stack
         then_ty = envStackType then_ids stack
         else_ty = envStackType else_ids stack
         sum_ty = mkTyConApp either_con [then_ty, else_ty]
         fvs_cond = exprFreeVars core_cond `intersectVarSet` local_vars
-    
-    core_if <- matchEnvStack env_ids stack_ids
-                (mkIfThenElse core_cond
-                    (left_expr  then_ty else_ty (buildEnvStack then_ids stack_ids))
-                    (right_expr then_ty else_ty (buildEnvStack else_ids stack_ids)))
+        
+        core_left  = mk_left_expr  then_ty else_ty (buildEnvStack then_ids stack_ids)
+        core_right = mk_right_expr then_ty else_ty (buildEnvStack else_ids stack_ids)
+
+    core_if <- case mb_fun of 
+       Just fun -> do { core_fun <- dsExpr fun
+                      ; matchEnvStack env_ids stack_ids $
+                        mkCoreApps core_fun [core_cond, core_left, core_right] }
+       Nothing  -> matchEnvStack env_ids stack_ids $
+                   mkIfThenElse core_cond core_left core_right
+
     return (do_map_arrow ids in_ty sum_ty res_ty
                 core_if
                 (do_choice ids then_ty else_ty res_ty core_then core_else),
@@ -1023,20 +1028,20 @@ See comments in HsUtils for why the other version does not include
 these bindings.
 
 \begin{code}
-collectPatBinders :: OutputableBndr a => LPat a -> [a]
+collectPatBinders :: LPat Id -> [Id]
 collectPatBinders pat = collectl pat []
 
-collectPatsBinders :: OutputableBndr a => [LPat a] -> [a]
+collectPatsBinders :: [LPat Id] -> [Id]
 collectPatsBinders pats = foldr collectl [] pats
 
 ---------------------
-collectl :: OutputableBndr a => LPat a -> [a] -> [a]
+collectl :: LPat Id -> [Id] -> [Id]
 -- See Note [Dictionary binders in ConPatOut]
 collectl (L _ pat) bndrs
   = go pat
   where
     go (VarPat var)               = var : bndrs
-    go (VarPatOut var bs)         = var : collectHsBindsBinders bs
+    go (VarPatOut var bs)         = var : collectEvBinders bs
                                     ++ bndrs
     go (WildPat _)                = bndrs
     go (LazyPat pat)              = collectl pat bndrs
@@ -1050,7 +1055,7 @@ collectl (L _ pat) bndrs
 
     go (ConPatIn _ ps)            = foldr collectl bndrs (hsConPatArgs ps)
     go (ConPatOut {pat_args=ps, pat_binds=ds}) =
-                                    collectHsBindsBinders ds
+                                    collectEvBinders ds
                                     ++ foldr collectl bndrs (hsConPatArgs ps)
     go (LitPat _)                 = bndrs
     go (NPat _ _ _)               = bndrs
@@ -1062,4 +1067,13 @@ collectl (L _ pat) bndrs
     go (CoPat _ pat _)            = collectl (noLoc pat) bndrs
     go (ViewPat _ pat _)          = collectl pat bndrs
     go p@(QuasiQuotePat {})       = pprPanic "collectl/go" (ppr p)
+
+collectEvBinders :: TcEvBinds -> [Id]
+collectEvBinders (EvBinds bs)   = foldrBag add_ev_bndr [] bs
+collectEvBinders (TcEvBinds {}) = panic "ToDo: collectEvBinders"
+
+add_ev_bndr :: EvBind -> [Id] -> [Id]
+add_ev_bndr (EvBind b _) bs | isId b    = b:bs
+                            | otherwise = bs
+  -- A worry: what about coercion variable binders??
 \end{code}