%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcClassDcl]{Typechecking class declarations}
#include "HsVersions.h"
import HsSyn ( HsDecl(..), ClassDecl(..), Sig(..), MonoBinds(..),
- InPat(..), andMonoBinds, getTyVarName
+ InPat(..), HsBinds(..), GRHSsAndBinds(..),
+ HsExpr(..), HsLit(..), HsType(..), pprClassAssertion,
+ unguardedRHS, andMonoBinds, andMonoBindList, getTyVarName
)
import HsPragmas ( ClassPragmas(..) )
-import BasicTypes ( NewOrData(..), TopLevelFlag(..), RecFlag(..) )
-import RnHsSyn ( RenamedClassDecl(..), RenamedClassPragmas(..),
- RenamedClassOpSig(..), RenamedMonoBinds,
- RenamedContext(..), RenamedHsDecl
+import BasicTypes ( NewOrData(..), TopLevelFlag(..), RecFlag(..), StrictnessMark(..) )
+import RnHsSyn ( RenamedClassDecl, RenamedClassPragmas,
+ RenamedClassOpSig, RenamedMonoBinds,
+ RenamedContext, RenamedHsDecl, RenamedSig
)
import TcHsSyn ( TcMonoBinds )
import Inst ( Inst, InstOrigin(..), LIE, emptyLIE, plusLIE, newDicts, newMethod )
-import TcEnv ( TcIdOcc(..), tcAddImportedIdInfo,
+import TcEnv ( TcIdOcc(..), GlobalValueEnv, tcAddImportedIdInfo,
tcLookupClass, tcLookupTyVar,
- tcExtendGlobalTyVars )
-import TcBinds ( tcBindWithSigs, checkSigTyVars, sigCtxt, TcSigInfo(..) )
-import TcKind ( unifyKinds, TcKind )
-import TcMonad
-import TcMonoType ( tcHsType, tcContext )
-import TcSimplify ( tcSimplifyAndCheck )
-import TcType ( TcType, TcTyVar, TcTyVarSet, tcInstSigTyVars,
- zonkSigTyVar, tcInstSigTcType
+ tcExtendGlobalTyVars, tcExtendLocalValEnv
)
-import PragmaInfo ( PragmaInfo(..) )
-
+import TcBinds ( tcBindWithSigs, tcPragmaSigs )
+import TcUnify ( unifyKinds )
+import TcMonad
+import TcMonoType ( tcHsType, tcContext, checkSigTyVars, sigCtxt, mkTcSig )
+import TcSimplify ( tcSimplifyAndCheck, bindInstsOfLocalFuns )
+import TcType ( TcType, TcTyVar, tcInstTyVars, zonkTcTyVarBndr )
+import PrelVals ( nO_METHOD_BINDING_ERROR_ID )
+import FieldLabel ( firstFieldLabelTag )
import Bag ( unionManyBags )
import Class ( mkClass, classBigSig, Class )
-import CmdLineOpts ( opt_GlasgowExts )
-import Id ( Id, StrictnessMark(..),
- mkSuperDictSelId, mkMethodSelId,
- mkDefaultMethodId, getIdUnfolding, mkDataCon,
- idType
+import CmdLineOpts ( opt_GlasgowExts, opt_WarnMissingMethods )
+import MkId ( mkSuperDictSelId, mkDataConId,
+ mkMethodSelId, mkDefaultMethodId
+ )
+import DataCon ( mkDataCon )
+import Id ( Id,
+ getIdUnfolding, idType, idName
)
import CoreUnfold ( getUnfoldingTemplate )
import IdInfo
-import Name ( Name, isLocallyDefined, OccName, nameOccName,
- NamedThing(..) )
+import Name ( Name, isLocallyDefined, NamedThing(..) )
import Outputable
-import Type ( mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy, splitRhoTy,
- mkSigmaTy, mkForAllTys, Type, ThetaType
+import Type ( mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy,
+ mkSigmaTy, mkForAllTys, Type, ThetaType,
+ boxedTypeKind, mkArrowKind
)
-import TyVar ( mkTyVarSet, tyVarKind, TyVar )
-import TyCon ( mkDataTyCon )
-import Kind ( mkBoxedTypeKind, mkArrowKind )
+import Var ( tyVarKind, TyVar )
+import VarSet ( mkVarSet )
+import TyCon ( mkAlgTyCon )
import Unique ( Unique, Uniquable(..) )
import Util
-import Maybes ( assocMaybe, maybeToBool )
+import Maybes ( seqMaybe )
-- import TcPragmas ( tcGenPragmas, tcClassOpPragmas )
tcGenPragmas ty id ps = returnNF_Tc noIdInfo
-tcClassOpPragmas ty sel def spec ps = returnNF_Tc (noIdInfo `addSpecInfo` spec,
+tcClassOpPragmas ty sel def spec ps = returnNF_Tc (spec `setSpecInfo` noIdInfo,
noIdInfo)
\end{code}
unifyKinds class_kinds tyvar_kinds `thenTc_`
-- CHECK THE CONTEXT
- tcClassContext rec_class rec_tyvars context pragmas
+ tcClassContext class_name rec_class rec_tyvars context pragmas
`thenTc` \ (sc_theta, sc_tys, sc_sel_ids) ->
-- CHECK THE CLASS SIGNATURES,
[_] -> NewType
other -> DataType
- dict_con_id = mkDataCon datacon_name
+ dict_con = mkDataCon datacon_name
[NotMarkedStrict | _ <- dict_component_tys]
[{- No labelled fields -}]
rec_tyvars
[{-No context-}]
[{-No existential tyvars-}] [{-Or context-}]
dict_component_tys
- tycon
+ tycon dict_con_id
+ dict_con_id = mkDataConId dict_con
- tycon = mkDataTyCon tycon_name
- (foldr (mkArrowKind . tyVarKind) mkBoxedTypeKind rec_tyvars)
+ tycon = mkAlgTyCon tycon_name
+ (foldr (mkArrowKind . tyVarKind) boxedTypeKind rec_tyvars)
rec_tyvars
[] -- No context
- [dict_con_id] -- Constructors
+ [dict_con] -- Constructors
[] -- No derivings
(Just clas) -- Yes! It's a dictionary
new_or_data
\begin{code}
-tcClassContext :: Class -> [TyVar]
+tcClassContext :: Name -> Class -> [TyVar]
-> RenamedContext -- class context
-> RenamedClassPragmas -- pragmas for superclasses
-> TcM s (ThetaType, -- the superclass context
[Type], -- types of the superclass dictionaries
[Id]) -- superclass selector Ids
-tcClassContext rec_class rec_tyvars context pragmas
+tcClassContext class_name rec_class rec_tyvars context pragmas
= -- Check the context.
-- The renamer has already checked that the context mentions
-- only the type variable of the class decl.
+
+ -- For std Haskell check that the context constrains only tyvars
+ (if opt_GlasgowExts then
+ returnTc []
+ else
+ mapTc check_constraint context
+ ) `thenTc_`
+
tcContext context `thenTc` \ sc_theta ->
+
let
sc_tys = [mkDictTy sc tys | (sc,tys) <- sc_theta]
in
-- D_sc1, D_sc2
-- (We used to call them D_C, but now we can have two different
-- superclasses both called C!)
- mapTc mk_super_id (sc_theta `zip` [1..]) `thenTc` \ sc_sel_ids ->
+ mapTc mk_super_id (sc_theta `zip` [firstFieldLabelTag..]) `thenTc` \ sc_sel_ids ->
-- Done
returnTc (sc_theta, sc_tys, sc_sel_ids)
in
returnTc (mkSuperDictSelId uniq rec_class index ty)
+ check_constraint (c, tys) = checkTc (all is_tyvar tys)
+ (superClassErr class_name (c, tys))
+
+ is_tyvar (MonoTyVar _) = True
+ is_tyvar other = False
-tcClassSig :: TcEnv s -- Knot tying only!
+
+tcClassSig :: GlobalValueEnv -- Knot tying only!
-> Class -- ...ditto...
-> [TyVar] -- The class type variable, used for error check only
-> RenamedClassOpSig
(tyvars, sc_theta, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
-- The selector binds are already in the selector Id's unfoldings
- sel_binds = [ CoreMonoBind (RealId sel_id) (getUnfoldingTemplate (getIdUnfolding sel_id))
- | sel_id <- sc_sel_ids ++ op_sel_ids,
- isLocallyDefined sel_id
- ]
-
- final_sel_binds = andMonoBinds sel_binds
+-- sel_binds = [ CoreMonoBind (RealId sel_id) (getUnfoldingTemplate (getIdUnfolding sel_id))
+-- | sel_id <- sc_sel_ids ++ op_sel_ids,
+-- isLocallyDefined sel_id
+-- ]
+--
+-- final_sel_binds = andMonoBindList sel_binds
in
-- Generate bindings for the default methods
tcDefaultMethodBinds clas default_binds `thenTc` \ (const_insts, meth_binds) ->
- returnTc (const_insts,
- final_sel_binds `AndMonoBinds` meth_binds)
+ returnTc (const_insts, meth_binds)
+-- final_sel_binds `AndMonoBinds` meth_binds)
+-- Leave 'em out for now. They always get inlined anyway. SLPJ June '98
\end{code}
%************************************************************************
tcDefaultMethodBinds clas default_binds
= -- Construct suitable signatures
- tcInstSigTyVars tyvars `thenNF_Tc` \ (clas_tyvars, inst_tys, inst_env) ->
+ tcInstTyVars tyvars `thenNF_Tc` \ (clas_tyvars, inst_tys, inst_env) ->
-- Typecheck the default bindings
let
- tc_dm meth_bind
- | not (maybeToBool maybe_stuff)
- = -- Binding for something that isn't in the class signature
- failWithTc (badMethodErr bndr_name clas)
-
- | otherwise
- = -- Normal case
- tcMethodBind clas origin inst_tys clas_tyvars sel_id meth_bind
- `thenTc` \ (bind, insts, (_, local_dm_id)) ->
+ tc_dm sel_id_w_dm@(_, Just dm_id)
+ = tcMethodBind clas origin inst_tys clas_tyvars
+ default_binds [{-no prags-}] False
+ sel_id_w_dm `thenTc` \ (bind, insts, (_, local_dm_id)) ->
returnTc (bind, insts, (clas_tyvars, RealId dm_id, local_dm_id))
- where
- bndr_name = case meth_bind of
- FunMonoBind name _ _ _ -> name
- PatMonoBind (VarPatIn name) _ _ -> name
-
- maybe_stuff = assocMaybe assoc_list (nameOccName bndr_name)
- assoc_list = [ (getOccName sel_id, pair)
- | pair@(sel_id, dm_ie) <- op_sel_ids `zip` defm_ids
- ]
- Just (sel_id, Just dm_id) = maybe_stuff
- -- We're looking at a default-method binding, so the dm_id
- -- is sure to be there! Hence the inner "Just".
in
- mapAndUnzip3Tc tc_dm
- (flatten default_binds []) `thenTc` \ (defm_binds, insts_needed, abs_bind_stuff) ->
+ mapAndUnzip3Tc tc_dm sel_ids_w_dms `thenTc` \ (defm_binds, insts_needed, abs_bind_stuff) ->
-- Check the context
newDicts origin [(clas,inst_tys)] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
avail_insts = this_dict
in
tcAddErrCtxt (classDeclCtxt clas) $
- mapNF_Tc zonkSigTyVar clas_tyvars `thenNF_Tc` \ clas_tyvars' ->
+
+ -- tcMethodBind has checked that the class_tyvars havn't
+ -- been unified with each other or another type, but we must
+ -- still zonk them
+ mapNF_Tc zonkTcTyVarBndr clas_tyvars `thenNF_Tc` \ clas_tyvars' ->
+
tcSimplifyAndCheck
(ptext SLIT("class") <+> ppr clas)
- (mkTyVarSet clas_tyvars')
+ (mkVarSet clas_tyvars')
avail_insts
(unionManyBags insts_needed) `thenTc` \ (const_lie, dict_binds) ->
clas_tyvars'
[this_dict_id]
abs_bind_stuff
- (dict_binds `AndMonoBinds` andMonoBinds defm_binds)
+ (dict_binds `andMonoBinds` andMonoBindList defm_binds)
in
returnTc (const_lie, full_binds)
where
(tyvars, sc_theta, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
- origin = ClassDeclOrigin
- flatten EmptyMonoBinds rest = rest
- flatten (AndMonoBinds b1 b2) rest = flatten b1 (flatten b2 rest)
- flatten a_bind rest = a_bind : rest
+ sel_ids_w_dms = [pair | pair@(_, Just _) <- op_sel_ids `zip` defm_ids]
+ -- Just the ones for which there is an explicit
+ -- user default declaration
+
+ origin = ClassDeclOrigin
\end{code}
@tcMethodBind@ is used to type-check both default-method and
tcMethodBind
:: Class
-> InstOrigin s
- -> [TcType s] -- Instance types
- -> [TcTyVar s] -- Free variables of those instance types
- -- they'll be signature tyvars, and we
- -- want to check that they don't bound
- -> Id -- The method selector
- -> RenamedMonoBinds -- Method binding (just one)
+ -> [TcType s] -- Instance types
+ -> [TcTyVar s] -- Free variables of those instance types
+ -- they'll be signature tyvars, and we
+ -- want to check that they don't bound
+ -> RenamedMonoBinds -- Method binding (pick the right one from in here)
+ -> [RenamedSig] -- Pramgas (just for this one)
+ -> Bool -- True <=> supply default decl if no explicit decl
+ -- This is true for instance decls,
+ -- false for class decls
+ -> (Id, Maybe Id) -- The method selector and default-method Id
-> TcM s (TcMonoBinds s, LIE s, (LIE s, TcIdOcc s))
-tcMethodBind clas origin inst_tys inst_tyvars sel_id meth_bind
- = tcAddSrcLoc src_loc $
- newMethod origin (RealId sel_id) inst_tys `thenNF_Tc` \ meth@(_, TcId local_meth_id) ->
- tcInstSigTcType (idType local_meth_id) `thenNF_Tc` \ (tyvars', rho_ty') ->
+tcMethodBind clas origin inst_tys inst_tyvars
+ meth_binds prags supply_default_bind
+ (sel_id, maybe_dm_id)
+ = tcGetSrcLoc `thenNF_Tc` \ loc ->
+
+ newMethod origin (RealId sel_id) inst_tys `thenNF_Tc` \ meth@(_, TcId meth_id) ->
+ mkTcSig meth_id loc `thenNF_Tc` \ sig_info ->
+
let
- (theta', tau') = splitRhoTy rho_ty'
- sig_info = TySigInfo bndr_name local_meth_id tyvars' theta' tau' src_loc
+ meth_name = idName meth_id
+ maybe_user_bind = find_bind meth_name meth_binds
+
+ no_user_bind = case maybe_user_bind of {Nothing -> True; other -> False}
+ no_user_default = case maybe_dm_id of {Nothing -> True; other -> False}
+
+ meth_bind = case maybe_user_bind of
+ Just bind -> bind
+ Nothing -> mk_default_bind meth_name loc
+
+ meth_prags = find_prags meth_name prags
in
- tcExtendGlobalTyVars inst_tyvars (
+
+ -- Warn if no method binding, only if -fwarn-missing-methods
+ if no_user_bind && not supply_default_bind then
+ pprPanic "tcMethodBind" (ppr clas <+> ppr inst_tys)
+ else
+ warnTc (opt_WarnMissingMethods && no_user_bind && no_user_default)
+ (omittedMethodWarn sel_id clas) `thenNF_Tc_`
+
+ -- Check the pragmas
+ tcExtendLocalValEnv [meth_name] [meth_id] (
+ tcPragmaSigs meth_prags
+ ) `thenTc` \ (prag_info_fn, prag_binds1, prag_lie) ->
+
+ -- Check the bindings
+ tcExtendGlobalTyVars (mkVarSet inst_tyvars) (
tcAddErrCtxt (methodCtxt sel_id) $
- tcBindWithSigs NotTopLevel [bndr_name] meth_bind [sig_info]
- NonRecursive (\_ -> NoPragmaInfo)
+ tcBindWithSigs NotTopLevel meth_bind [sig_info]
+ NonRecursive prag_info_fn
) `thenTc` \ (binds, insts, _) ->
+
+ -- The prag_lie for a SPECIALISE pragma will mention the function
+ -- itself, so we have to simplify them away right now lest they float
+ -- outwards!
+ bindInstsOfLocalFuns prag_lie [meth_id] `thenTc` \ (prag_lie', prag_binds2) ->
+
+
-- Now check that the instance type variables
-- (or, in the case of a class decl, the class tyvars)
-- have not been unified with anything in the environment
- tcAddErrCtxt (monoCtxt sel_id) (
- tcAddErrCtxt (sigCtxt sel_id) $
- checkSigTyVars inst_tyvars (idType local_meth_id)
- ) `thenTc_`
+ tcAddErrCtxtM (sigCtxt (quotes (ppr sel_id)) (idType meth_id)) (
+ checkSigTyVars inst_tyvars `thenTc_`
+
+ returnTc (binds `AndMonoBinds` prag_binds1 `AndMonoBinds` prag_binds2,
+ insts `plusLIE` prag_lie',
+ meth))
- returnTc (binds, insts, meth)
where
- (bndr_name, src_loc) = case meth_bind of
- FunMonoBind name _ _ loc -> (name, loc)
- PatMonoBind (VarPatIn name) _ loc -> (name, loc)
+ sel_name = idName sel_id
+
+ -- The renamer just puts the selector ID as the binder in the method binding
+ -- but we must use the method name; so we substitute it here. Crude but simple.
+ find_bind meth_name (FunMonoBind op_name fix matches loc)
+ | op_name == sel_name = Just (FunMonoBind meth_name fix matches loc)
+ find_bind meth_name (PatMonoBind (VarPatIn op_name) rhs loc)
+ | op_name == sel_name = Just (PatMonoBind (VarPatIn meth_name) rhs loc)
+ find_bind meth_name (AndMonoBinds b1 b2)
+ = find_bind meth_name b1 `seqMaybe` find_bind meth_name b2
+ find_bind meth_name other = Nothing -- Default case
+
+
+ -- Find the prags for this method, and replace the
+ -- selector name with the method name
+ find_prags meth_name [] = []
+ find_prags meth_name (SpecSig name ty spec loc : prags)
+ | name == sel_name = SpecSig meth_name ty spec loc : find_prags meth_name prags
+ find_prags meth_name (InlineSig name loc : prags)
+ | name == sel_name = InlineSig meth_name loc : find_prags meth_name prags
+ find_prags meth_name (NoInlineSig name loc : prags)
+ | name == sel_name = NoInlineSig meth_name loc : find_prags meth_name prags
+ find_prags meth_name (prag:prags) = find_prags meth_name prags
+
+ mk_default_bind local_meth_name loc
+ = PatMonoBind (VarPatIn local_meth_name)
+ (GRHSsAndBindsIn (unguardedRHS (default_expr loc) loc) EmptyBinds)
+ loc
+
+ default_expr loc
+ = case maybe_dm_id of
+ Just dm_id -> HsVar (getName dm_id) -- There's a default method
+ Nothing -> error_expr loc -- No default method
+
+ error_expr loc = HsApp (HsVar (getName nO_METHOD_BINDING_ERROR_ID))
+ (HsLit (HsString (_PK_ (error_msg loc))))
+
+ error_msg loc = showSDoc (hcat [ppr loc, text "|", ppr sel_id ])
\end{code}
Contexts and errors
classDeclCtxt class_name
= ptext SLIT("In the class declaration for") <+> quotes (ppr class_name)
+superClassErr class_name sc
+ = ptext SLIT("Illegal superclass constraint") <+> quotes (pprClassAssertion sc)
+ <+> ptext SLIT("in declaration for class") <+> quotes (ppr class_name)
+
methodCtxt sel_id
= ptext SLIT("In the definition for method") <+> quotes (ppr sel_id)
-monoCtxt sel_id
- = sep [ptext SLIT("Probable cause: the right hand side of") <+> quotes (ppr sel_id),
- nest 4 (ptext SLIT("mentions a top-level variable subject to the dreaded monomorphism restriction"))
- ]
-
badMethodErr bndr clas
= hsep [ptext SLIT("Class"), quotes (ppr clas),
ptext SLIT("does not have a method"), quotes (ppr bndr)]
+
+omittedMethodWarn sel_id clas
+ = sep [ptext SLIT("No explicit method nor default method for") <+> quotes (ppr sel_id),
+ ptext SLIT("in an instance declaration for") <+> quotes (ppr clas)]
\end{code}
projects / ghc-hetmet.git / blobdiff