[project @ 2002-10-18 13:41:50 by simonpj]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcEnv.lhs

diff --git a/ghc/compiler/typecheck/TcEnv.lhs b/ghc/compiler/typecheck/TcEnv.lhs
index ec0e3b8..5d53dae 100644 (file)
--- a/ghc/compiler/typecheck/TcEnv.lhs
+++ b/ghc/compiler/typecheck/TcEnv.lhs
@@ -6,6 +6,7 @@ module TcEnv(
        tcGetInstEnv, tcSetInstEnv, 
        InstInfo(..), pprInstInfo, pprInstInfoDetails,
        simpleInstInfoTy, simpleInstInfoTyCon, 
+       InstBindings(..),
 
        -- Global environment
        tcExtendGlobalEnv, 
@@ -572,19 +573,25 @@ as well as explicit user written ones.
 data InstInfo
   = InstInfo {
       iDFunId :: DFunId,               -- The dfun id
-      iBinds  :: RenamedMonoBinds,     -- Bindings, b
-      iPrags  :: [RenamedSig]          -- User pragmas recorded for generating specialised instances
+      iBinds  :: InstBindings
     }
 
-  | NewTypeDerived {           -- Used for deriving instances of newtypes, where the
-                               -- witness dictionary is identical to the argument dictionary
-                               -- Hence no bindings.
-      iDFunId :: DFunId                        -- The dfun id
-    }
+data InstBindings
+  = VanillaInst                -- The normal case
+       RenamedMonoBinds        -- Bindings
+       [RenamedSig]            -- User pragmas recorded for generating 
+                               -- specialised instances
+
+  | NewTypeDerived             -- Used for deriving instances of newtypes, where the
+       [Type]                  -- witness dictionary is identical to the argument 
+                               -- dictionary.  Hence no bindings, no pragmas
+       -- The [Type] are the representation types
+       -- See notes in TcDeriv
 
 pprInstInfo info = vcat [ptext SLIT("InstInfo:") <+> ppr (idType (iDFunId info))]
-pprInstInfoDetails (InstInfo { iBinds = b }) = ppr b
-pprInstInfoDetails (NewTypeDerived _)       = text "Derived from the represenation type"
+
+pprInstInfoDetails (InstInfo { iBinds = VanillaInst b _ }) = ppr b
+pprInstInfoDetails (InstInfo { iBinds = NewTypeDerived _}) = text "Derived from the represenation type"
 
 simpleInstInfoTy :: InstInfo -> Type
 simpleInstInfoTy info = case tcSplitDFunTy (idType (iDFunId info)) of