#include "HsVersions.h"
import HsSyn ( HsDecl(..), ClassDecl(..), Sig(..), MonoBinds(..),
- InPat(..), andMonoBinds, getTyVarName
+ InPat(..), HsBinds(..), GRHSsAndBinds(..), GRHS(..),
+ HsExpr(..), HsLit(..),
+ unguardedRHS, andMonoBinds, getTyVarName
)
import HsPragmas ( ClassPragmas(..) )
import BasicTypes ( NewOrData(..), TopLevelFlag(..), RecFlag(..) )
-import RnHsSyn ( RenamedClassDecl(..), RenamedClassPragmas(..),
- RenamedClassOpSig(..), RenamedMonoBinds,
- RenamedContext(..), RenamedHsDecl, RenamedSig
+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, tcExtendLocalValEnv
)
-import TcBinds ( tcBindWithSigs, checkSigTyVars, sigCtxt, tcPragmaSigs, TcSigInfo(..) )
+import TcBinds ( tcBindWithSigs, bindInstsOfLocalFuns,
+ checkSigTyVars, sigCtxt, tcPragmaSigs, TcSigInfo(..)
+ )
import TcKind ( unifyKinds, TcKind )
import TcMonad
import TcMonoType ( tcHsType, tcContext )
import TcType ( TcType, TcTyVar, TcTyVarSet, tcInstSigTyVars,
zonkSigTyVar, tcInstSigTcType
)
+import PrelVals ( nO_METHOD_BINDING_ERROR_ID )
import FieldLabel ( firstFieldLabelTag )
import Bag ( unionManyBags )
import Class ( mkClass, classBigSig, Class )
-import CmdLineOpts ( opt_GlasgowExts )
+import CmdLineOpts ( opt_GlasgowExts, opt_WarnMissingMethods )
import MkId ( mkDataCon, mkSuperDictSelId,
mkMethodSelId, mkDefaultMethodId
)
import Id ( Id, StrictnessMark(..),
- getIdUnfolding, idType
+ getIdUnfolding, idType, idName
)
import CoreUnfold ( getUnfoldingTemplate )
import IdInfo
import Kind ( mkBoxedTypeKind, mkArrowKind )
import Unique ( Unique, Uniquable(..) )
import Util
-import Maybes ( assocMaybe, maybeToBool )
+import Maybes ( assocMaybe, maybeToBool, seqMaybe )
-- import TcPragmas ( tcGenPragmas, tcClassOpPragmas )
returnTc (mkSuperDictSelId uniq rec_class index ty)
-tcClassSig :: TcEnv s -- Knot tying only!
+tcClassSig :: GlobalValueEnv -- Knot tying only!
-> Class -- ...ditto...
-> [TyVar] -- The class type variable, used for error check only
-> RenamedClassOpSig
-- 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 [{- No prags -}]
- `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]) ->
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)
- -> [RenamedSig] -- Pramgas (just for this 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 prags
- = 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)
+ | no_user_bind && not supply_default_bind
+ = pprPanic "tcMethodBind" (ppr clas <+> ppr inst_tys)
+
+ | otherwise
+ = tcGetSrcLoc `thenNF_Tc` \ loc ->
+
+ -- Warn if no method binding, only if -fwarn-missing-methods
+ warnTc (opt_WarnMissingMethods && no_user_bind && no_user_default)
+ (omittedMethodWarn sel_id clas) `thenNF_Tc_`
+
+ newMethod origin (RealId sel_id) inst_tys `thenNF_Tc` \ meth@(_, TcId meth_id) ->
+ tcInstSigTcType (idType meth_id) `thenNF_Tc` \ (tyvars', rho_ty') ->
let
- (theta', tau') = splitRhoTy rho_ty'
- sig_info = TySigInfo bndr_name local_meth_id tyvars' theta' tau' src_loc
+ (theta', tau') = splitRhoTy rho_ty'
+
+ meth_name = idName meth_id
+ sig_info = TySigInfo meth_name meth_id tyvars' theta' tau' loc
+ meth_bind = mk_meth_bind meth_name loc
+ meth_prags = find_prags meth_name prags
in
- tcExtendLocalValEnv [bndr_name] [local_meth_id] (
- tcPragmaSigs prags
- ) `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+ tcExtendLocalValEnv [meth_name] [meth_id] (
+ tcPragmaSigs meth_prags
+ ) `thenTc` \ (prag_info_fn, prag_binds1, prag_lie) ->
+ -- Check that the signatures match
tcExtendGlobalTyVars inst_tyvars (
tcAddErrCtxt (methodCtxt sel_id) $
- tcBindWithSigs NotTopLevel [bndr_name] meth_bind [sig_info]
+ tcBindWithSigs NotTopLevel [meth_name] 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)
+ checkSigTyVars inst_tyvars (idType meth_id)
) `thenTc_`
- returnTc (binds `AndMonoBinds` prag_binds,
- insts `plusLIE` prag_lie,
+ returnTc (binds `AndMonoBinds` prag_binds1 `AndMonoBinds` prag_binds2,
+ insts `plusLIE` prag_lie',
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
+
+ maybe_user_bind = find 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}
+
+ find EmptyMonoBinds = Nothing
+ find (AndMonoBinds b1 b2) = find b1 `seqMaybe` find b2
+ find b@(FunMonoBind op_name _ _ _) = if op_name == sel_name then Just b else Nothing
+ find b@(PatMonoBind (VarPatIn op_name) _ _) = if op_name == sel_name then Just b else Nothing
+ find other = panic "Urk! Bad instance method binding"
+
+ -- 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.
+ mk_meth_bind meth_name loc
+ = case maybe_user_bind of
+ Just (FunMonoBind _ fix matches loc) -> FunMonoBind meth_name fix matches loc
+ Just (PatMonoBind (VarPatIn _) rhs loc) -> PatMonoBind (VarPatIn meth_name) rhs loc
+ Nothing -> mk_default_bind meth_name loc
+
+ -- 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 (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
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