X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnBinds.lhs;h=b0dd3b52f4cfbc95dcf7554dc77727397207665d;hp=a18dfcef115e19eb9809848ec7ed09968320532d;hb=60401bfe16c49ef2e06e5e81fd58e030bea02013;hpb=fbff1b7b9c89f6369c4394a0b10fa7c06e011698

diff --git a/compiler/rename/RnBinds.lhs b/compiler/rename/RnBinds.lhs
index a18dfce..b0dd3b5 100644
--- a/compiler/rename/RnBinds.lhs
+++ b/compiler/rename/RnBinds.lhs
@@ -713,7 +713,9 @@ renameSig mb_names sig@(TypeSig v ty)
 	; return (TypeSig new_v new_ty) }
 
 renameSig mb_names sig@(GenericSig v ty)
-  = do	{ new_v <- lookupSigOccRn mb_names sig v
+  = do	{ generics_on <- xoptM Opt_Generics
+        ; unless generics_on (addErr (genericSigErr sig))
+        ; new_v <- lookupSigOccRn mb_names sig v
 	; new_ty <- rnHsSigType (quotes (ppr v)) ty
 	; return (GenericSig new_v new_ty) } -- JPM: ?
 
@@ -838,6 +840,11 @@ misplacedSigErr (L loc sig)
   = addErrAt loc $
     sep [ptext (sLit "Misplaced") <+> hsSigDoc sig <> colon, ppr sig]
 
+genericSigErr :: Sig RdrName -> SDoc
+genericSigErr sig = vcat [ hang (ptext (sLit "Unexpected generic default signature:"))
+                              2 (ppr sig)
+                         , ptext (sLit "Use -XGenerics to enable generic default signatures") ] 
+
 methodBindErr :: HsBindLR RdrName RdrName -> SDoc
 methodBindErr mbind
  =  hang (ptext (sLit "Pattern bindings (except simple variables) not allowed in instance declarations"))
@@ -852,4 +859,5 @@ nonStdGuardErr :: [LStmtLR Name Name] -> SDoc
 nonStdGuardErr guards
   = hang (ptext (sLit "accepting non-standard pattern guards (use -XPatternGuards to suppress this message)"))
        4 (interpp'SP guards)
+
 \end{code}