[project @ 1997-05-26 04:51:57 by sof]

Updated imports; common AbsBinds cases optimised

diff --git a/ghc/compiler/deSugar/DsBinds.lhs b/ghc/compiler/deSugar/DsBinds.lhs
index 6a1bc06..901274d 100644 (file)
--- a/ghc/compiler/deSugar/DsBinds.lhs
+++ b/ghc/compiler/deSugar/DsBinds.lhs
@@ -34,12 +34,12 @@ import Id           ( idType, SYN_IE(DictVar), GenId, SYN_IE(Id) )
 import ListSetOps      ( minusList, intersectLists )
 import Name            ( isExported )
 import PprType         ( GenType )
-import PprStyle                ( PprStyle(..) )
+import Outputable      ( PprStyle(..) )
 import Type            ( mkTyVarTy, isDictTy, instantiateTy
                        )
 import TyVar           ( tyVarSetToList, GenTyVar{-instance Eq-} )
 import TysPrim         ( voidTy )
-import Util            ( isIn, panic{-, pprTrace ToDo:rm-} )
+import Util            ( isIn, panic, assertPanic  )
 \end{code}
 
 %************************************************************************
@@ -106,10 +106,22 @@ dsMonoBinds is_rec (PatMonoBind pat grhss_and_binds locn)
     dsGuarded grhss_and_binds                  `thenDs` \ body_expr ->
     mkSelectorBinds pat body_expr
 
-dsMonoBinds is_rec (AbsBinds [] [] exports binds)      -- Common special case
+       -- Common special case: no type or dictionary abstraction
+dsMonoBinds is_rec (AbsBinds [] [] exports binds)
   = dsMonoBinds is_rec binds                   `thenDs` \ prs ->
     returnDs (prs ++ [(global, Var local) | (_, global, local) <- exports])
 
+       -- Another common case: one exported variable
+       -- All non-recursive bindings come through this way
+dsMonoBinds is_rec (AbsBinds all_tyvars dicts [(tyvars, global, local)] binds)
+  = ASSERT( all (`elem` tyvars) all_tyvars )
+    dsMonoBinds is_rec binds                           `thenDs` \ core_prs ->
+    let 
+       core_binds | is_rec    = [Rec core_prs]
+                  | otherwise = [NonRec b e | (b,e) <- core_prs]
+    in
+    returnDs [(global, mkLam tyvars dicts $ mkCoLetsAny core_binds (Var local))]
+
 dsMonoBinds is_rec (AbsBinds all_tyvars dicts exports binds)
   = dsMonoBinds is_rec binds                           `thenDs` \ core_prs ->
     let