vectoriser: fix warning

[ghc-hetmet.git] / compiler / vectorise / Vectorise / Type / PADict.hs

diff --git a/compiler/vectorise/Vectorise/Type/PADict.hs b/compiler/vectorise/Vectorise/Type/PADict.hs
index 677a7bf..6c94ae0 100644 (file)
--- a/compiler/vectorise/Vectorise/Type/PADict.hs
+++ b/compiler/vectorise/Vectorise/Type/PADict.hs
@@ -19,11 +19,11 @@ import TypeRep
 import Id
 import Var
 import Name
-import Outputable
 import Class
+import Outputable
 
-debug          = False
-dtrace s x     = if debug then pprTrace "Vectoris.Type.PADict" s x else x
+-- debug               = False
+-- dtrace s x  = if debug then pprTrace "Vectoris.Type.PADict" s x else x
 
 -- | Build the PA dictionary for some type and hoist it to top level.
 --   The PA dictionary holds fns that convert values to and from their vectorised representations.
@@ -35,9 +35,10 @@ buildPADict
        -> VM Var       -- ^ name of the top-level dictionary function.
 
 buildPADict vect_tc prepr_tc arr_tc repr
- = dtrace (text "buildPADict" <+> ppr vect_tc <+> ppr prepr_tc <+> ppr arr_tc)
- $ polyAbstract tvs $ \args@[] ->
- do
+ = polyAbstract tvs $ \args ->
+ case args of
+  (_:_) -> pprPanic "Vectorise.Type.PADict.buildPADict" (text "why do we need superclass dicts?")
+  [] -> do
       -- TODO: I'm forcing args to [] because I'm not sure why we need them.
       --       class PA has superclass (PR (PRepr a)) but we're not using
       --       the superclass dictionary to build the PA dictionary.
@@ -51,23 +52,12 @@ buildPADict vect_tc prepr_tc arr_tc repr
                $ mkConApp pa_dc
                $ Type inst_ty : map (method_call args) method_ids
 
-      dtrace (text "dict    = " <+> ppr dict) $ return ()
-
       -- Build the type of the dictionary function.
-      pa_tc          <- builtin paTyCon
-      let pa_opitems = [(id, NoDefMeth) | id <- method_ids]
-      let pa_cls     = mkClass 
-                       (tyConName pa_tc)
-                       tvs             -- tyvars of class
-                       []              -- fundeps
-                       []              -- superclass predicates
-                       []              -- superclass dict selectors
-                       []              -- associated type families
-                       pa_opitems      -- class op items
-                       pa_tc           -- dictionary type constructor
-                       
-      let dfun_ty = mkForAllTys tvs
-                  $ mkFunTys (map varType args) (PredTy $ ClassP pa_cls [inst_ty])
+      pa_tc            <- builtin paTyCon
+      let Just pa_cls  = tyConClass_maybe pa_tc
+
+      let dfun_ty      = mkForAllTys tvs
+                       $ mkFunTys (map varType args) (PredTy $ ClassP pa_cls [inst_ty])
 
       -- Set the unfolding for the inliner.
       raw_dfun <- newExportedVar dfun_name dfun_ty