[project @ 2004-04-02 16:46:57 by simonpj]

[ghc-hetmet.git] / ghc / compiler / hsSyn / HsDecls.lhs

diff --git a/ghc/compiler/hsSyn/HsDecls.lhs b/ghc/compiler/hsSyn/HsDecls.lhs
index 930dcdc..827bec8 100644 (file)
--- a/ghc/compiler/hsSyn/HsDecls.lhs
+++ b/ghc/compiler/hsSyn/HsDecls.lhs
@@ -306,9 +306,13 @@ data TyClDecl name
                tcdLName  :: Located name,              -- Type constructor
                tcdTyVars :: [LHsTyVarBndr name],       -- Type variables
                tcdCons   :: [LConDecl name],           -- Data constructors
-               tcdDerivs :: Maybe (LHsContext name)    
+               tcdDerivs :: Maybe [LHsType name]
                        -- Derivings; Nothing => not specified
                        --            Just [] => derive exactly what is asked
+                       -- These "types" must be of form
+                       --      forall ab. C ty1 ty2
+                       -- Typically the foralls and ty args are empty, but they
+                       -- are non-empty for the newtype-deriving case
     }
 
   | TySynonym {        tcdLName  :: Located name,              -- type constructor
@@ -433,8 +437,7 @@ pp_tydecl pp_head pp_decl_rhs derivings
        pp_decl_rhs,
        case derivings of
          Nothing          -> empty
-         Just ds          -> hsep [ptext SLIT("deriving"), 
-                                       ppr_hs_context (unLoc ds)]
+         Just ds          -> hsep [ptext SLIT("deriving"), parens (interpp'SP ds)]
     ])
 
 instance Outputable NewOrData where