\begin{code}
module TcClassDcl ( tcClassSigs, tcClassDecl2,
findMethodBind, instantiateMethod, tcInstanceMethodBody,
- mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName,
+ mkGenericDefMethBind, getGenericInstances,
tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn
) where
import HsSyn
import RnHsSyn
import RnExpr
-import RnEnv
import Inst
import InstEnv
import TcEnv
import TcMType
import TcType
import TcRnMonad
+import BuildTyCl( TcMethInfo )
import Generics
import Class
import TyCon
import Var
import NameEnv
import NameSet
-import RdrName
import Outputable
import PrelNames
import DynFlags
-> LHsBinds Name
-> TcM [TcMethInfo]
-type TcMethInfo = (Name, DefMeth, Type) -- A temporary intermediate, to communicate
- -- between tcClassSigs and buildClass
tcClassSigs clas sigs def_methods
- = do { dm_env <- checkDefaultBinds clas op_names def_methods
- ; mapM (tcClassSig dm_env) op_sigs }
+ = do { dm_env <- mapM (addLocM (checkDefaultBind clas op_names))
+ (bagToList def_methods)
+ ; mapM (tcClassSig (mkNameEnv dm_env)) op_sigs }
where
op_sigs = [sig | sig@(L _ (TypeSig _ _)) <- sigs]
op_names = [n | (L _ (TypeSig (L _ n) _)) <- op_sigs]
-
-checkDefaultBinds :: Name -> [Name] -> LHsBinds Name -> TcM (NameEnv Bool)
+checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, DefMethSpec)
-- Check default bindings
-- a) must be for a class op for this class
-- b) must be all generic or all non-generic
- -- and return a mapping from class-op to Bool
- -- where True <=> it's a generic default method
-checkDefaultBinds clas ops binds
- = do dm_infos <- mapM (addLocM (checkDefaultBind clas ops)) (bagToList binds)
- return (mkNameEnv dm_infos)
-
-checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, Bool)
checkDefaultBind clas ops (FunBind {fun_id = L _ op, fun_matches = MatchGroup matches _ })
= do { -- Check that the op is from this class
- checkTc (op `elem` ops) (badMethodErr clas op)
+ checkTc (op `elem` ops) (badMethodErr clas op)
-- Check that all the defns ar generic, or none are
- ; checkTc (all_generic || none_generic) (mixedGenericErr op)
-
- ; return (op, all_generic)
+ ; case (none_generic, all_generic) of
+ (True, _) -> return (op, VanillaDM)
+ (_, True) -> return (op, GenericDM)
+ _ -> failWith (mixedGenericErr op)
}
where
n_generic = count (isJust . maybeGenericMatch) matches
none_generic = n_generic == 0
all_generic = matches `lengthIs` n_generic
+
checkDefaultBind _ _ b = pprPanic "checkDefaultBind" (ppr b)
-tcClassSig :: NameEnv Bool -- Info about default methods;
+tcClassSig :: NameEnv DefMethSpec -- Info about default methods;
-> LSig Name
-> TcM TcMethInfo
tcClassSig dm_env (L loc (TypeSig (L _ op_name) op_hs_ty))
= setSrcSpan loc $ do
{ op_ty <- tcHsKindedType op_hs_ty -- Class tyvars already in scope
- ; let dm = case lookupNameEnv dm_env op_name of
- Nothing -> NoDefMeth
- Just False -> DefMeth
- Just True -> GenDefMeth
+ ; let dm = lookupNameEnv dm_env op_name `orElse` NoDM
; return (op_name, dm, op_ty) }
tcClassSig _ s = pprPanic "tcClassSig" (ppr s)
\end{code}
; let tc_dm = tcDefMeth clas clas_tyvars
this_dict default_binds
sig_fn prag_fn
- -- tc_dm is called only for a sel_id
- -- that has a binding in default_binds
-
- dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items]
- -- Generate code for polymorphic default methods only (hence DefMeth)
- -- (Generic default methods have turned into instance decls by now.)
- -- This is incompatible with Hugs, which expects a polymorphic
- -- default method for every class op, regardless of whether or not
- -- the programmer supplied an explicit default decl for the class.
- -- (If necessary we can fix that, but we don't have a convenient Id to hand.)
- ; (dm_ids, defm_binds) <- tcExtendTyVarEnv clas_tyvars $
- mapAndUnzipM tc_dm dm_sel_ids
+ ; dm_stuff <- tcExtendTyVarEnv clas_tyvars $
+ mapM tc_dm op_items
+ ; let (dm_ids, defm_binds) = unzip (catMaybes dm_stuff)
; return (dm_ids, listToBag defm_binds) }
tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d)
tcDefMeth :: Class -> [TyVar] -> Inst -> LHsBinds Name
- -> TcSigFun -> TcPragFun -> Id
- -> TcM (Id, LHsBind Id)
-tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn sel_id
- = do { let sel_name = idName sel_id
- ; dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name)
- ; local_dm_name <- newLocalName sel_name
- -- Base the local_dm_name on the selector name, becuase
+ -> TcSigFun -> TcPragFun -> ClassOpItem
+ -> TcM (Maybe (Id, LHsBind Id))
+-- Generate code for polymorphic default methods only (hence DefMeth)
+-- (Generic default methods have turned into instance decls by now.)
+-- This is incompatible with Hugs, which expects a polymorphic
+-- default method for every class op, regardless of whether or not
+-- the programmer supplied an explicit default decl for the class.
+-- (If necessary we can fix that, but we don't have a convenient Id to hand.)
+tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn (sel_id, dm_info)
+ = case dm_info of
+ NoDefMeth -> return Nothing
+ GenDefMeth -> return Nothing
+ DefMeth dm_name -> do
+ { let sel_name = idName sel_id
+ ; local_dm_name <- newLocalName sel_name
+ -- Base the local_dm_name on the selector name, because
-- type errors from tcInstanceMethodBody come from here
-- See Note [Silly default-method bind]
; let meth_bind = findMethodBind sel_name local_dm_name binds_in
`orElse` pprPanic "tcDefMeth" (ppr sel_id)
- -- We only call tcDefMeth on selectors for which
- -- there is a binding in binds_in
+ -- dm_info = DefMeth dm_name only if there is a binding in binds_in
dm_sig_fn _ = sig_fn sel_name
dm_ty = idType sel_id
(ptext (sLit "Ignoring SPECIALISE pragmas on default method")
<+> quotes (ppr sel_name))
- ; tcInstanceMethodBody (instLoc this_dict)
+ ; liftM Just $
+ tcInstanceMethodBody (instLoc this_dict)
tyvars [this_dict]
([], emptyBag)
dm_id_w_inline local_dm_id
\end{code}
\begin{code}
-mkDefMethRdrName :: Name -> RdrName
-mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc
-
instantiateMethod :: Class -> Id -> [TcType] -> TcType
-- Take a class operation, say
-- op :: forall ab. C a => forall c. Ix c => (b,c) -> a
projects / ghc-hetmet.git / blobdiff