Added error checks & fixed bugs

[ghc-hetmet.git] / compiler / parser / RdrHsSyn.lhs

diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs
index 980c7f7..a8449ae 100644 (file)
--- a/compiler/parser/RdrHsSyn.lhs
+++ b/compiler/parser/RdrHsSyn.lhs
@@ -38,6 +38,7 @@ module RdrHsSyn (
        checkTyClHdr,         -- LHsContext RdrName -> LHsType RdrName -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName])
        checkTyVars,          -- [LHsType RdrName] -> Bool -> P ()
        checkSynHdr,          -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], Maybe [LHsType RdrName])
+       checkKindSigs,        -- [LTyClDecl RdrName] -> P ()
        checkTopTypeD,        -- LTyClDecl RdrName -> P (HsDecl RdrName)
        checkInstType,        -- HsType -> P HsType
        checkPattern,         -- HsExp -> P HsPat
@@ -213,7 +214,7 @@ cvBindsAndSigs :: OrdList (LHsDecl RdrName)
   -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName])
 -- Input decls contain just value bindings and signatures
 -- and in case of class or instance declarations also
--- associated data or synonym definitions
+-- associated type declarations
 cvBindsAndSigs  fb = go (fromOL fb)
   where
     go []                 = (emptyBag, [], [])
@@ -506,6 +507,17 @@ extractTyVars tvs = collects [] tvs
                            tvs' <- collects tvs ts
                            collect tvs' t
 
+-- Check that associated type declarations of a class are all kind signatures.
+--
+checkKindSigs :: [LTyClDecl RdrName] -> P ()
+checkKindSigs = mapM_ check
+  where
+    check (L l tydecl) 
+      | isKindSigDecl tydecl
+        || isSynDecl tydecl  = return ()
+      | otherwise           = 
+       parseError l "Type declaration in a class must be a kind signature or synonym default"
+
 -- Wrap a toplevel type or data declaration into 'TyClD' and ensure for 
 -- data declarations that all type parameters are variables only (which is in
 -- contrast to type functions and associated type declarations).