Big tidy-up of deriving code

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

diff --git a/compiler/typecheck/TcHsType.lhs b/compiler/typecheck/TcHsType.lhs
index 3d365ab..86870c9 100644 (file)
--- a/compiler/typecheck/TcHsType.lhs
+++ b/compiler/typecheck/TcHsType.lhs
@@ -6,7 +6,8 @@
 
 \begin{code}
 module TcHsType (
-       tcHsSigType, tcHsDeriv,
+       tcHsSigType, tcHsDeriv, 
+       tcHsInstHead, tcHsQuantifiedType,
        UserTypeCtxt(..), 
 
                -- Kind checking
@@ -143,6 +144,24 @@ tcHsSigType ctxt hs_ty
        ; checkValidType ctxt ty        
        ; returnM ty }
 
+tcHsInstHead :: LHsType Name -> TcM ([TyVar], ThetaType, Type)
+-- Typecheck an instance head.  We can't use 
+-- tcHsSigType, because it's not a valid user type.
+tcHsInstHead hs_ty
+  = do { kinded_ty <- kcHsSigType hs_ty
+       ; poly_ty   <- tcHsKindedType kinded_ty
+       ; return (tcSplitSigmaTy poly_ty) }
+
+tcHsQuantifiedType :: [LHsTyVarBndr Name] -> LHsType Name -> TcM ([TyVar], Type)
+-- Behave very like type-checking (HsForAllTy sig_tvs hs_ty),
+-- except that we want to keep the tvs separate
+tcHsQuantifiedType tv_names hs_ty
+  = kcHsTyVars tv_names $ \ tv_names' ->
+    do { kc_ty <- kcHsSigType hs_ty
+       ; tcTyVarBndrs tv_names' $ \ tvs ->
+    do { ty <- dsHsType kc_ty
+       ; return (tvs, ty) } }
+
 -- Used for the deriving(...) items
 tcHsDeriv :: LHsType Name -> TcM ([TyVar], Class, [Type])
 tcHsDeriv = addLocM (tc_hs_deriv [])
@@ -388,13 +407,21 @@ kc_pred :: HsPred Name -> TcM (HsPred Name, TcKind)
        -- Does *not* check for a saturated
        -- application (reason: used from TcDeriv)
 kc_pred pred@(HsIParam name ty)
-  = kcHsType ty                `thenM` \ (ty', kind) ->
-    returnM (HsIParam name ty', kind)
-
+  = do { (ty', kind) <- kcHsType ty
+       ; returnM (HsIParam name ty', kind)
+       }
 kc_pred pred@(HsClassP cls tys)
-  = kcClass cls                        `thenM` \ kind ->
-    kcApps kind (ppr cls) tys  `thenM` \ (tys', res_kind) ->
-    returnM (HsClassP cls tys', res_kind)
+  = do { kind <- kcClass cls
+       ; (tys', res_kind) <- kcApps kind (ppr cls) tys
+       ; returnM (HsClassP cls tys', res_kind)
+       }
+kc_pred pred@(HsEqualP ty1 ty2)
+  = do { (ty1', kind1) <- kcHsType ty1
+       ; checkExpectedKind ty1 kind1 liftedTypeKind
+       ; (ty2', kind2) <- kcHsType ty2
+       ; checkExpectedKind ty2 kind2 liftedTypeKind
+       ; returnM (HsEqualP ty1 ty2, liftedTypeKind)
+       }
 
 ---------------------------
 kcTyVar :: Name -> TcM TcKind
@@ -498,6 +525,9 @@ ds_type full_ty@(HsForAllTy exp tv_names ctxt ty)
 
 ds_type (HsSpliceTy {}) = panic "ds_type: HsSpliceTy"
 
+ds_type (HsDocTy ty _)  -- Remove the doc comment
+  = dsHsType ty
+
 dsHsTypes arg_tys = mappM dsHsType arg_tys
 \end{code}
 
@@ -534,13 +564,19 @@ dsHsLPred :: LHsPred Name -> TcM PredType
 dsHsLPred pred = dsHsPred (unLoc pred)
 
 dsHsPred pred@(HsClassP class_name tys)
-  = dsHsTypes tys                      `thenM` \ arg_tys ->
-    tcLookupClass class_name           `thenM` \ clas ->
-    returnM (ClassP clas arg_tys)
-
+  = do { arg_tys <- dsHsTypes tys
+       ; clas <- tcLookupClass class_name
+       ; returnM (ClassP clas arg_tys)
+       }
+dsHsPred pred@(HsEqualP ty1 ty2)
+  = do { arg_ty1 <- dsHsType ty1
+       ; arg_ty2 <- dsHsType ty2
+       ; returnM (EqPred arg_ty1 arg_ty2)
+       }
 dsHsPred (HsIParam name ty)
-  = dsHsType ty                                        `thenM` \ arg_ty ->
-    returnM (IParam name arg_ty)
+  = do { arg_ty <- dsHsType ty
+       ; returnM (IParam name arg_ty)
+       }
 \end{code}
 
 GADT constructor signatures
@@ -612,7 +648,7 @@ tcTyVarBndrs bndrs thing_inside
   where
     zonk (KindedTyVar name kind) = do { kind' <- zonkTcKindToKind kind
                                      ; return (mkTyVar name kind') }
-    zonk (UserTyVar name) = pprTrace "Un-kinded tyvar" (ppr name) $
+    zonk (UserTyVar name) = WARN( True, ptext SLIT("Un-kinded tyvar") <+> ppr name )
                            return (mkTyVar name liftedTypeKind)
 
 -----------------------------------
@@ -708,16 +744,10 @@ tcHsPatSigType ctxt hs_ty
                        | n <- nameSetToList (extractHsTyVars hs_ty),
                          not (in_scope n) ]
 
-       -- Behave very like type-checking (HsForAllTy sig_tvs hs_ty),
-       -- except that we want to keep the tvs separate
-       ; (kinded_tvs, kinded_ty) <- kcHsTyVars sig_tvs $ \ kinded_tvs -> do
-                                   { kinded_ty <- kcTypeType hs_ty
-                                   ; return (kinded_tvs, kinded_ty) }
-       ; tcTyVarBndrs kinded_tvs $ \ tyvars -> do
-       { sig_ty <- dsHsType kinded_ty
+       ; (tyvars, sig_ty) <- tcHsQuantifiedType sig_tvs hs_ty
        ; checkValidType ctxt sig_ty 
        ; return (tyvars, sig_ty)
-      } }
+      }
 
 tcPatSig :: UserTypeCtxt
         -> LHsType Name
@@ -800,7 +830,6 @@ pprHsSigCtxt ctxt hs_ty = vcat [ ptext SLIT("In") <+> pprUserTypeCtxt ctxt <> co
     pp_sig (FunSigCtxt n)  = pp_n_colon n
     pp_sig (ConArgCtxt n)  = pp_n_colon n
     pp_sig (ForSigCtxt n)  = pp_n_colon n
-    pp_sig (RuleSigCtxt n) = pp_n_colon n
     pp_sig other          = ppr (unLoc hs_ty)
 
     pp_n_colon n = ppr n <+> dcolon <+> ppr (unLoc hs_ty)