%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcBinds]{TcBinds}
\begin{code}
-#include "HsVersions.h"
+module TcBinds ( tcBindsAndThen, tcTopBindsAndThen,
+ tcPragmaSigs, tcBindWithSigs ) where
-module TcBinds ( tcBindsAndThen, tcPragmaSigs, checkSigTyVars, tcBindWithSigs, TcSigInfo(..) ) where
+#include "HsVersions.h"
-IMP_Ubiq()
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201
-IMPORT_DELOOPER(TcLoop) ( tcGRHSsAndBinds )
-#else
import {-# SOURCE #-} TcGRHSs ( tcGRHSsAndBinds )
-#endif
-
-import HsSyn ( HsBinds(..), Sig(..), MonoBinds(..),
- Match, HsType, InPat(..), OutPat(..), HsExpr(..),
- SYN_IE(RecFlag), nonRecursive,
- GRHSsAndBinds, ArithSeqInfo, HsLit, Fake, Stmt, DoOrListComp, Fixity,
- collectMonoBinders )
-import RnHsSyn ( SYN_IE(RenamedHsBinds), RenamedSig(..),
- SYN_IE(RenamedMonoBinds)
+import {-# SOURCE #-} TcExpr ( tcExpr )
+
+import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), InPat(..), StmtCtxt(..),
+ collectMonoBinders, andMonoBindList, andMonoBinds
)
-import TcHsSyn ( SYN_IE(TcHsBinds), SYN_IE(TcMonoBinds),
- TcIdOcc(..), SYN_IE(TcIdBndr), SYN_IE(TcExpr),
- tcIdType
+import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
+import TcHsSyn ( TcHsBinds, TcMonoBinds,
+ TcIdOcc(..), TcIdBndr,
+ tcIdType, zonkId
)
import TcMonad
-import Inst ( Inst, SYN_IE(LIE), emptyLIE, plusLIE, InstOrigin(..),
- newDicts, tyVarsOfInst, instToId
+import Inst ( Inst, LIE, emptyLIE, mkLIE, plusLIE, plusLIEs, InstOrigin(..),
+ newDicts, tyVarsOfInst, instToId,
)
-import TcEnv ( tcExtendLocalValEnv, tcLookupLocalValueOK, newMonoIds,
+import TcEnv ( tcExtendLocalValEnv, tcExtendEnvWithPat,
+ tcLookupLocalValueOK,
+ newSpecPragmaId,
tcGetGlobalTyVars, tcExtendGlobalTyVars
)
-import SpecEnv ( SpecEnv )
import TcMatches ( tcMatchesFun )
import TcSimplify ( tcSimplify, tcSimplifyAndCheck )
-import TcMonoType ( tcHsType )
-import TcPat ( tcPat )
+import TcMonoType ( tcHsTcType, checkSigTyVars,
+ TcSigInfo(..), tcTySig, maybeSig, sigCtxt
+ )
+import TcPat ( tcVarPat, tcPat )
import TcSimplify ( bindInstsOfLocalFuns )
-import TcType ( SYN_IE(TcType), SYN_IE(TcThetaType), SYN_IE(TcTauType),
- SYN_IE(TcTyVarSet), SYN_IE(TcTyVar),
- newTyVarTy, zonkTcType, zonkTcTyVar, zonkTcTyVars,
- newTcTyVar, tcInstSigType, newTyVarTys
+import TcType ( TcType, TcThetaType,
+ TcTyVar,
+ newTyVarTy, newTcTyVar, tcInstTcType,
+ zonkTcType, zonkTcTypes, zonkTcThetaType )
+import TcUnify ( unifyTauTy, unifyTauTyLists )
+
+import Id ( mkUserId )
+import Var ( idType, idName, setIdInfo )
+import IdInfo ( IdInfo, noIdInfo, setInlinePragInfo, InlinePragInfo(..) )
+import Name ( Name )
+import Type ( mkTyVarTy, tyVarsOfTypes,
+ splitSigmaTy, mkForAllTys, mkFunTys, getTyVar,
+ mkDictTy, splitRhoTy, mkForAllTy, isUnLiftedType,
+ isUnboxedType, openTypeKind,
+ unboxedTypeKind, boxedTypeKind
)
-import Unify ( unifyTauTy, unifyTauTyLists )
-
-import Kind ( isUnboxedTypeKind, mkTypeKind, isTypeKind, mkBoxedTypeKind )
-import Id ( GenId, idType, mkUserLocal, mkUserId )
-import IdInfo ( noIdInfo )
-import Maybes ( maybeToBool, assocMaybe, catMaybes )
-import Name ( getOccName, getSrcLoc, Name )
-import PragmaInfo ( PragmaInfo(..) )
-import Pretty
-import Type ( mkTyVarTy, mkTyVarTys, isTyVarTy, tyVarsOfTypes, eqSimpleTheta,
- mkSigmaTy, splitSigmaTy, mkForAllTys, mkFunTys, getTyVar, mkDictTy,
- splitRhoTy, mkForAllTy, splitForAllTy )
-import TyVar ( GenTyVar, SYN_IE(TyVar), tyVarKind, minusTyVarSet, emptyTyVarSet,
- elementOfTyVarSet, unionTyVarSets, tyVarSetToList )
-import Bag ( bagToList, foldrBag, isEmptyBag )
-import Util ( isIn, zipEqual, zipWithEqual, zipWith3Equal, hasNoDups, assoc,
- assertPanic, panic, pprTrace )
-import PprType ( GenClass, GenType, GenTyVar )
-import Unique ( Unique )
+import Var ( TyVar, tyVarKind )
+import VarSet
+import Bag
+import Util ( isIn )
+import BasicTypes ( TopLevelFlag(..), RecFlag(..) )
import SrcLoc ( SrcLoc )
-
-import Outputable --( interppSP, interpp'SP )
-
-
+import Outputable
\end{code}
dictionaries, which we resolve at the module level.
\begin{code}
-tcBindsAndThen
- :: (TcHsBinds s -> thing -> thing) -- Combinator
+tcTopBindsAndThen, tcBindsAndThen
+ :: (RecFlag -> TcMonoBinds s -> thing -> thing) -- Combinator
-> RenamedHsBinds
-> TcM s (thing, LIE s)
-> TcM s (thing, LIE s)
-tcBindsAndThen combiner EmptyBinds do_next
- = do_next `thenTc` \ (thing, lie) ->
- returnTc (combiner EmptyBinds thing, lie)
+tcTopBindsAndThen = tc_binds_and_then TopLevel
+tcBindsAndThen = tc_binds_and_then NotTopLevel
+
+tc_binds_and_then top_lvl combiner EmptyBinds do_next
+ = do_next
+tc_binds_and_then top_lvl combiner (MonoBind EmptyMonoBinds sigs is_rec) do_next
+ = do_next
-tcBindsAndThen combiner (ThenBinds binds1 binds2) do_next
- = tcBindsAndThen combiner binds1 (tcBindsAndThen combiner binds2 do_next)
+tc_binds_and_then top_lvl combiner (ThenBinds b1 b2) do_next
+ = tc_binds_and_then top_lvl combiner b1 $
+ tc_binds_and_then top_lvl combiner b2 $
+ do_next
-tcBindsAndThen combiner (MonoBind bind sigs is_rec) do_next
- = fixTc (\ ~(prag_info_fn, _) ->
+tc_binds_and_then top_lvl combiner (MonoBind bind sigs is_rec) do_next
+ = fixTc (\ ~(prag_info_fn, _, _) ->
-- This is the usual prag_info fix; the PragmaInfo field of an Id
-- is not inspected till ages later in the compiler, so there
-- should be no black-hole problems here.
-- TYPECHECK THE SIGNATURES
- mapTc (tcTySig prag_info_fn) ty_sigs `thenTc` \ tc_ty_sigs ->
-
- tcBindWithSigs binder_names bind
- tc_ty_sigs is_rec prag_info_fn `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
-
- -- Extend the environment to bind the new polymorphic Ids
- tcExtendLocalValEnv binder_names poly_ids $
-
- -- Build bindings and IdInfos corresponding to user pragmas
- tcPragmaSigs sigs `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+ mapTc tcTySig [sig | sig@(Sig name _ _) <- sigs] `thenTc` \ tc_ty_sigs ->
+
+ tcBindWithSigs top_lvl bind
+ tc_ty_sigs is_rec prag_info_fn `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
+
+ -- Extend the environment to bind the new polymorphic Ids
+ tcExtendLocalValEnv (map idName poly_ids) poly_ids $
+
+ -- Build bindings and IdInfos corresponding to user pragmas
+ tcPragmaSigs sigs `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
-- Now do whatever happens next, in the augmented envt
- do_next `thenTc` \ (thing, thing_lie) ->
+ do_next `thenTc` \ (thing, thing_lie) ->
-- Create specialisations of functions bound here
- bindInstsOfLocalFuns (prag_lie `plusLIE` thing_lie)
- poly_ids `thenTc` \ (lie2, inst_mbinds) ->
-
- -- All done
- let
- final_lie = lie2 `plusLIE` poly_lie
- final_binds = MonoBind poly_binds [] is_rec `ThenBinds`
- MonoBind inst_mbinds [] nonRecursive `ThenBinds`
- prag_binds
- in
- returnTc (prag_info_fn, (combiner final_binds thing, final_lie))
- ) `thenTc` \ (_, result) ->
- returnTc result
- where
- binder_names = map fst (bagToList (collectMonoBinders bind))
- ty_sigs = [sig | sig@(Sig name _ _) <- sigs]
-
+ -- We want to keep non-recursive things non-recursive
+ -- so that we desugar unboxed bindings correctly
+ case (top_lvl, is_rec) of
+
+ -- For the top level don't bother will all this bindInstsOfLocalFuns stuff
+ -- All the top level things are rec'd together anyway, so it's fine to
+ -- leave them to the tcSimplifyTop, and quite a bit faster too
+ (TopLevel, _)
+ -> returnTc (prag_info_fn,
+ combiner Recursive (poly_binds `andMonoBinds` prag_binds) thing,
+ thing_lie `plusLIE` prag_lie `plusLIE` poly_lie)
+
+ (NotTopLevel, NonRecursive)
+ -> bindInstsOfLocalFuns
+ (thing_lie `plusLIE` prag_lie)
+ poly_ids `thenTc` \ (thing_lie', lie_binds) ->
+
+ returnTc (
+ prag_info_fn,
+ combiner NonRecursive poly_binds $
+ combiner NonRecursive prag_binds $
+ combiner Recursive lie_binds $
+ -- NB: the binds returned by tcSimplify and bindInstsOfLocalFuns
+ -- aren't guaranteed in dependency order (though we could change
+ -- that); hence the Recursive marker.
+ thing,
+
+ thing_lie' `plusLIE` poly_lie
+ )
+
+ (NotTopLevel, Recursive)
+ -> bindInstsOfLocalFuns
+ (thing_lie `plusLIE` poly_lie `plusLIE` prag_lie)
+ poly_ids `thenTc` \ (final_lie, lie_binds) ->
+
+ returnTc (
+ prag_info_fn,
+ combiner Recursive (
+ poly_binds `andMonoBinds`
+ lie_binds `andMonoBinds`
+ prag_binds) thing,
+ final_lie
+ )
+ ) `thenTc` \ (_, thing, lie) ->
+ returnTc (thing, lie)
\end{code}
An aside. The original version of @tcBindsAndThen@ which lacks a
examples of this, which is why I thought it worth preserving! [SLPJ]
\begin{pseudocode}
-tcBindsAndThen
- :: RenamedHsBinds
- -> TcM s (thing, LIE s, thing_ty))
- -> TcM s ((TcHsBinds s, thing), LIE s, thing_ty)
-
-tcBindsAndThen EmptyBinds do_next
- = do_next `thenTc` \ (thing, lie, thing_ty) ->
- returnTc ((EmptyBinds, thing), lie, thing_ty)
-
-tcBindsAndThen (ThenBinds binds1 binds2) do_next
- = tcBindsAndThen binds1 (tcBindsAndThen binds2 do_next)
- `thenTc` \ ((binds1', (binds2', thing')), lie1, thing_ty) ->
-
- returnTc ((binds1' `ThenBinds` binds2', thing'), lie1, thing_ty)
-
-tcBindsAndThen (MonoBind bind sigs is_rec) do_next
- = tcBindAndThen bind sigs do_next
+% tcBindsAndThen
+% :: RenamedHsBinds
+% -> TcM s (thing, LIE s, thing_ty))
+% -> TcM s ((TcHsBinds s, thing), LIE s, thing_ty)
+%
+% tcBindsAndThen EmptyBinds do_next
+% = do_next `thenTc` \ (thing, lie, thing_ty) ->
+% returnTc ((EmptyBinds, thing), lie, thing_ty)
+%
+% tcBindsAndThen (ThenBinds binds1 binds2) do_next
+% = tcBindsAndThen binds1 (tcBindsAndThen binds2 do_next)
+% `thenTc` \ ((binds1', (binds2', thing')), lie1, thing_ty) ->
+%
+% returnTc ((binds1' `ThenBinds` binds2', thing'), lie1, thing_ty)
+%
+% tcBindsAndThen (MonoBind bind sigs is_rec) do_next
+% = tcBindAndThen bind sigs do_next
\end{pseudocode}
\begin{code}
tcBindWithSigs
- :: [Name]
+ :: TopLevelFlag
-> RenamedMonoBinds
-> [TcSigInfo s]
-> RecFlag
- -> (Name -> PragmaInfo)
+ -> (Name -> IdInfo)
-> TcM s (TcMonoBinds s, LIE s, [TcIdBndr s])
-tcBindWithSigs binder_names mbind tc_ty_sigs is_rec prag_info_fn
+tcBindWithSigs top_lvl mbind tc_ty_sigs is_rec prag_info_fn
= recoverTc (
-- If typechecking the binds fails, then return with each
-- signature-less binder given type (forall a.a), to minimise subsequent
-- error messages
- newTcTyVar mkBoxedTypeKind `thenNF_Tc` \ alpha_tv ->
+ newTcTyVar boxedTypeKind `thenNF_Tc` \ alpha_tv ->
let
- forall_a_a = mkForAllTy alpha_tv (mkTyVarTy alpha_tv)
- poly_ids = map mk_dummy binder_names
+ forall_a_a = mkForAllTy alpha_tv (mkTyVarTy alpha_tv)
+ binder_names = map fst (bagToList (collectMonoBinders mbind))
+ poly_ids = map mk_dummy binder_names
mk_dummy name = case maybeSig tc_ty_sigs name of
- Just (TySigInfo _ poly_id _ _ _ _) -> poly_id -- Signature
- Nothing -> mkUserId name forall_a_a NoPragmaInfo -- No signature
+ Just (TySigInfo _ poly_id _ _ _ _ _ _) -> poly_id -- Signature
+ Nothing -> mkUserId name forall_a_a -- No signature
in
returnTc (EmptyMonoBinds, emptyLIE, poly_ids)
) $
- -- Create a new identifier for each binder, with each being given
- -- a fresh unique, and a type-variable type.
- tcGetUniques no_of_binders `thenNF_Tc` \ uniqs ->
- mapNF_Tc mk_mono_id_ty binder_names `thenNF_Tc` \ mono_id_tys ->
+ -- TYPECHECK THE BINDINGS
+ tcMonoBinds mbind tc_ty_sigs is_rec `thenTc` \ (mbind', lie_req, binder_names, mono_ids) ->
+
let
- mono_id_tyvars = tyVarsOfTypes mono_id_tys
- mono_ids = zipWith3Equal "tcBindAndSigs" mk_id binder_names uniqs mono_id_tys
- mk_id name uniq ty = mkUserLocal (getOccName name) uniq ty (getSrcLoc name)
+ mono_id_tys = map idType mono_ids
in
- -- TYPECHECK THE BINDINGS
- tcMonoBinds mbind binder_names mono_ids tc_ty_sigs `thenTc` \ (mbind', lie) ->
-
-- CHECK THAT THE SIGNATURES MATCH
-- (must do this before getTyVarsToGen)
- checkSigMatch tc_ty_sigs `thenTc` \ sig_theta ->
-
+ checkSigMatch tc_ty_sigs `thenTc` \ (sig_theta, lie_avail) ->
+
-- COMPUTE VARIABLES OVER WHICH TO QUANTIFY, namely tyvars_to_gen
-- The tyvars_not_to_gen are free in the environment, and hence
-- candidates for generalisation, but sometimes the monomorphism
-- restriction means we can't generalise them nevertheless
- getTyVarsToGen is_unrestricted mono_id_tyvars lie `thenTc` \ (tyvars_not_to_gen, tyvars_to_gen) ->
+ getTyVarsToGen is_unrestricted mono_id_tys lie_req `thenNF_Tc` \ (tyvars_not_to_gen, tyvars_to_gen) ->
-- DEAL WITH TYPE VARIABLE KINDS
- mapTc defaultUncommittedTyVar (tyVarSetToList tyvars_to_gen) `thenTc` \ tyvars_to_gen_list ->
- -- It's important that the final list (tyvars_to_gen_list) is fully
+ -- **** This step can do unification => keep other zonking after this ****
+ mapTc defaultUncommittedTyVar (varSetElems tyvars_to_gen) `thenTc` \ real_tyvars_to_gen_list ->
+ let
+ real_tyvars_to_gen = mkVarSet real_tyvars_to_gen_list
+ -- It's important that the final list
+ -- (real_tyvars_to_gen and real_tyvars_to_gen_list) is fully
-- zonked, *including boxity*, because they'll be included in the forall types of
-- the polymorphic Ids, and instances of these Ids will be generated from them.
- --
- -- This step can do unification => keep other zonking after this
+ --
+ -- Also NB that tcSimplify takes zonked tyvars as its arg, hence we pass
+ -- real_tyvars_to_gen
+ in
-- SIMPLIFY THE LIE
tcExtendGlobalTyVars tyvars_not_to_gen (
+ if null real_tyvars_to_gen_list then
+ -- No polymorphism, so no need to simplify context
+ returnTc (lie_req, EmptyMonoBinds, [])
+ else
if null tc_ty_sigs then
-- No signatures, so just simplify the lie
- tcSimplify tyvars_to_gen lie `thenTc` \ (lie_free, dict_binds, lie_bound) ->
+ -- NB: no signatures => no polymorphic recursion, so no
+ -- need to use lie_avail (which will be empty anyway)
+ tcSimplify (text "tcBinds1" <+> ppr binder_names)
+ top_lvl real_tyvars_to_gen lie_req `thenTc` \ (lie_free, dict_binds, lie_bound) ->
returnTc (lie_free, dict_binds, map instToId (bagToList lie_bound))
else
- zonk_theta sig_theta `thenNF_Tc` \ sig_theta' ->
+ zonkTcThetaType sig_theta `thenNF_Tc` \ sig_theta' ->
newDicts SignatureOrigin sig_theta' `thenNF_Tc` \ (dicts_sig, dict_ids) ->
-- It's important that sig_theta is zonked, because
-- dict_id is later used to form the type of the polymorphic thing,
-- and forall-types must be zonked so far as their bound variables
-- are concerned
+ let
+ -- The "givens" is the stuff available. We get that from
+ -- the context of the type signature, BUT ALSO the lie_avail
+ -- so that polymorphic recursion works right (see comments at end of fn)
+ givens = dicts_sig `plusLIE` lie_avail
+ in
+
-- Check that the needed dicts can be expressed in
-- terms of the signature ones
- tcAddErrCtxt (sigsCtxt tysig_names) $
- tcSimplifyAndCheck tyvars_to_gen dicts_sig lie `thenTc` \ (lie_free, dict_binds) ->
+ tcAddErrCtxt (bindSigsCtxt tysig_names) $
+ tcSimplifyAndCheck
+ (ptext SLIT("type signature for") <+> pprQuotedList binder_names)
+ real_tyvars_to_gen givens lie_req `thenTc` \ (lie_free, dict_binds) ->
+
returnTc (lie_free, dict_binds, dict_ids)
) `thenTc` \ (lie_free, dict_binds, dicts_bound) ->
- ASSERT( not (any (isUnboxedTypeKind . tyVarKind) tyvars_to_gen_list) )
+ -- GET THE FINAL MONO_ID_TYS
+ zonkTcTypes mono_id_tys `thenNF_Tc` \ zonked_mono_id_types ->
+
+
+ -- CHECK FOR BOGUS UNPOINTED BINDINGS
+ (if any isUnLiftedType zonked_mono_id_types then
+ -- Unlifted bindings must be non-recursive,
+ -- not top level, and non-polymorphic
+ checkTc (case top_lvl of {TopLevel -> False; NotTopLevel -> True})
+ (unliftedBindErr "Top-level" mbind) `thenTc_`
+ checkTc (case is_rec of {Recursive -> False; NonRecursive -> True})
+ (unliftedBindErr "Recursive" mbind) `thenTc_`
+ checkTc (null real_tyvars_to_gen_list)
+ (unliftedBindErr "Polymorphic" mbind)
+ else
+ returnTc ()
+ ) `thenTc_`
+
+ ASSERT( not (any ((== unboxedTypeKind) . tyVarKind) real_tyvars_to_gen_list) )
-- The instCantBeGeneralised stuff in tcSimplify should have
- -- already raised an error if we're trying to generalise an unboxed tyvar
- -- (NB: unboxed tyvars are always introduced along with a class constraint)
- -- and it's better done there because we have more precise origin information.
+ -- already raised an error if we're trying to generalise an
+ -- unboxed tyvar (NB: unboxed tyvars are always introduced
+ -- along with a class constraint) and it's better done there
+ -- because we have more precise origin information.
-- That's why we just use an ASSERT here.
+
-- BUILD THE POLYMORPHIC RESULT IDs
- mapNF_Tc zonkTcType mono_id_tys `thenNF_Tc` \ zonked_mono_id_types ->
+ mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids ->
let
- exports = zipWith3 mk_export binder_names mono_ids zonked_mono_id_types
+ exports = zipWith mk_export binder_names zonked_mono_ids
dict_tys = map tcIdType dicts_bound
- mk_export binder_name mono_id zonked_mono_id_ty
- | maybeToBool maybe_sig = (sig_tyvars, TcId sig_poly_id, TcId mono_id)
- | otherwise = (tyvars_to_gen_list, TcId poly_id, TcId mono_id)
+ mk_export binder_name zonked_mono_id
+ = (tyvars,
+ TcId (setIdInfo poly_id (prag_info_fn binder_name)),
+ TcId zonked_mono_id)
where
- maybe_sig = maybeSig tc_ty_sigs binder_name
- Just (TySigInfo _ sig_poly_id sig_tyvars _ _ _) = maybe_sig
- poly_id = mkUserId binder_name poly_ty (prag_info_fn binder_name)
- poly_ty = mkForAllTys tyvars_to_gen_list $ mkFunTys dict_tys $ zonked_mono_id_ty
- -- It's important to build a fully-zonked poly_ty, because
- -- we'll slurp out its free type variables when extending the
- -- local environment (tcExtendLocalValEnv); if it's not zonked
- -- it appears to have free tyvars that aren't actually free at all.
+ (tyvars, poly_id) =
+ case maybeSig tc_ty_sigs binder_name of
+ Just (TySigInfo _ sig_poly_id sig_tyvars _ _ _ _ _) ->
+ (sig_tyvars, sig_poly_id)
+ Nothing -> (real_tyvars_to_gen_list, new_poly_id)
+
+ new_poly_id = mkUserId binder_name poly_ty
+ poly_ty = mkForAllTys real_tyvars_to_gen_list
+ $ mkFunTys dict_tys
+ $ idType (zonked_mono_id)
+ -- It's important to build a fully-zonked poly_ty, because
+ -- we'll slurp out its free type variables when extending the
+ -- local environment (tcExtendLocalValEnv); if it's not zonked
+ -- it appears to have free tyvars that aren't actually free
+ -- at all.
+
+ pat_binders :: [Name]
+ pat_binders = map fst $ bagToList $ collectMonoBinders $
+ (justPatBindings mbind EmptyMonoBinds)
in
+ -- CHECK FOR UNBOXED BINDERS IN PATTERN BINDINGS
+ mapTc (\id -> checkTc (not (idName id `elem` pat_binders
+ && isUnboxedType (idType id)))
+ (unboxedPatBindErr id)) zonked_mono_ids
+ `thenTc_`
-- BUILD RESULTS
returnTc (
- AbsBinds tyvars_to_gen_list
+ AbsBinds real_tyvars_to_gen_list
dicts_bound
exports
- (dict_binds `AndMonoBinds` mbind'),
+ (dict_binds `andMonoBinds` mbind'),
lie_free,
[poly_id | (_, TcId poly_id, _) <- exports]
)
where
- no_of_binders = length binder_names
+ tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- tc_ty_sigs]
+ is_unrestricted = isUnRestrictedGroup tysig_names mbind
- mk_mono_id_ty binder_name = case maybeSig tc_ty_sigs binder_name of
- Just (TySigInfo name _ _ _ tau_ty _) -> returnNF_Tc tau_ty -- There's a signature
- otherwise -> newTyVarTy kind -- No signature
+justPatBindings bind@(PatMonoBind _ _ _) binds = bind `andMonoBinds` binds
+justPatBindings (AndMonoBinds b1 b2) binds =
+ justPatBindings b1 (justPatBindings b2 binds)
+justPatBindings other_bind binds = binds
+\end{code}
- tysig_names = [name | (TySigInfo name _ _ _ _ _) <- tc_ty_sigs]
- is_unrestricted = isUnRestrictedGroup tysig_names mbind
+Polymorphic recursion
+~~~~~~~~~~~~~~~~~~~~~
+The game plan for polymorphic recursion in the code above is
- kind | is_rec = mkBoxedTypeKind -- Recursive, so no unboxed types
- | otherwise = mkTypeKind -- Non-recursive, so we permit unboxed types
+ * Bind any variable for which we have a type signature
+ to an Id with a polymorphic type. Then when type-checking
+ the RHSs we'll make a full polymorphic call.
-zonk_theta theta = mapNF_Tc zonk theta
- where
- zonk (c,t) = zonkTcType t `thenNF_Tc` \ t' ->
- returnNF_Tc (c,t')
-\end{code}
+This fine, but if you aren't a bit careful you end up with a horrendous
+amount of partial application and (worse) a huge space leak. For example:
+
+ f :: Eq a => [a] -> [a]
+ f xs = ...f...
+
+If we don't take care, after typechecking we get
+
+ f = /\a -> \d::Eq a -> let f' = f a d
+ in
+ \ys:[a] -> ...f'...
+
+Notice the the stupid construction of (f a d), which is of course
+identical to the function we're executing. In this case, the
+polymorphic recursion isn't being used (but that's a very common case).
+We'd prefer
+
+ f = /\a -> \d::Eq a -> letrec
+ fm = \ys:[a] -> ...fm...
+ in
+ fm
+
+This can lead to a massive space leak, from the following top-level defn
+(post-typechecking)
+
+ ff :: [Int] -> [Int]
+ ff = f Int dEqInt
+
+Now (f dEqInt) evaluates to a lambda that has f' as a free variable; but
+f' is another thunk which evaluates to the same thing... and you end
+up with a chain of identical values all hung onto by the CAF ff.
+
+ ff = f Int dEqInt
+
+ = let f' = f Int dEqInt in \ys. ...f'...
+
+ = let f' = let f' = f Int dEqInt in \ys. ...f'...
+ in \ys. ...f'...
-@getImplicitStuffToGen@ decides what type variables generalise over.
+Etc.
+Solution: when typechecking the RHSs we always have in hand the
+*monomorphic* Ids for each binding. So we just need to make sure that
+if (Method f a d) shows up in the constraints emerging from (...f...)
+we just use the monomorphic Id. We achieve this by adding monomorphic Ids
+to the "givens" when simplifying constraints. That's what the "lies_avail"
+is doing.
+
+
+%************************************************************************
+%* *
+\subsection{getTyVarsToGen}
+%* *
+%************************************************************************
+
+@getTyVarsToGen@ decides what type variables generalise over.
For a "restricted group" -- see the monomorphism restriction
for a definition -- we bind no dictionaries, and
find which tyvars are constrained.
\begin{code}
-getTyVarsToGen is_unrestricted mono_tyvars lie
- = tcGetGlobalTyVars `thenNF_Tc` \ free_tyvars ->
- zonkTcTyVars mono_tyvars `thenNF_Tc` \ mentioned_tyvars ->
+getTyVarsToGen is_unrestricted mono_id_tys lie
+ = tcGetGlobalTyVars `thenNF_Tc` \ free_tyvars ->
+ zonkTcTypes mono_id_tys `thenNF_Tc` \ zonked_mono_id_tys ->
let
- tyvars_to_gen = mentioned_tyvars `minusTyVarSet` free_tyvars
+ tyvars_to_gen = tyVarsOfTypes zonked_mono_id_tys `minusVarSet` free_tyvars
in
if is_unrestricted
then
- returnTc (emptyTyVarSet, tyvars_to_gen)
+ returnNF_Tc (emptyVarSet, tyvars_to_gen)
else
- tcSimplify tyvars_to_gen lie `thenTc` \ (_, _, constrained_dicts) ->
+ -- This recover and discard-errs is to avoid duplicate error
+ -- messages; this, after all, is an "extra" call to tcSimplify
+ recoverNF_Tc (returnNF_Tc (emptyVarSet, tyvars_to_gen)) $
+ discardErrsTc $
+
+ tcSimplify (text "getTVG") NotTopLevel tyvars_to_gen lie `thenTc` \ (_, _, constrained_dicts) ->
let
-- ASSERT: dicts_sig is already zonked!
- constrained_tyvars = foldrBag (unionTyVarSets . tyVarsOfInst) emptyTyVarSet constrained_dicts
- reduced_tyvars_to_gen = tyvars_to_gen `minusTyVarSet` constrained_tyvars
+ constrained_tyvars = foldrBag (unionVarSet . tyVarsOfInst) emptyVarSet constrained_dicts
+ reduced_tyvars_to_gen = tyvars_to_gen `minusVarSet` constrained_tyvars
in
returnTc (constrained_tyvars, reduced_tyvars_to_gen)
\end{code}
\begin{code}
defaultUncommittedTyVar tyvar
- | isTypeKind (tyVarKind tyvar)
- = newTcTyVar mkBoxedTypeKind `thenNF_Tc` \ boxed_tyvar ->
- unifyTauTy (mkTyVarTy boxed_tyvar) (mkTyVarTy tyvar) `thenTc_`
+ | tyVarKind tyvar == openTypeKind
+ = newTcTyVar boxedTypeKind `thenNF_Tc` \ boxed_tyvar ->
+ unifyTauTy (mkTyVarTy tyvar) (mkTyVarTy boxed_tyvar) `thenTc_`
returnTc boxed_tyvar
| otherwise
\begin{code}
tcMonoBinds :: RenamedMonoBinds
- -> [Name] -> [TcIdBndr s]
-> [TcSigInfo s]
- -> TcM s (TcMonoBinds s, LIE s)
-
-tcMonoBinds mbind binder_names mono_ids tc_ty_sigs
- = tcExtendLocalValEnv binder_names mono_ids (
- tc_mono_binds mbind
- )
+ -> RecFlag
+ -> TcM s (TcMonoBinds s,
+ LIE s, -- LIE required
+ [Name], -- Bound names
+ [TcIdBndr s]) -- Corresponding monomorphic bound things
+
+tcMonoBinds mbinds tc_ty_sigs is_rec
+ = tc_mb_pats mbinds `thenTc` \ (complete_it, lie_req_pat, tvs, ids, lie_avail) ->
+ let
+ tv_list = bagToList tvs
+ (names, mono_ids) = unzip (bagToList ids)
+ in
+ -- Don't know how to deal with pattern-bound existentials yet
+ checkTc (isEmptyBag tvs && isEmptyBag lie_avail)
+ (existentialExplode mbinds) `thenTc_`
+
+ -- *Before* checking the RHSs, but *after* checking *all* the patterns,
+ -- extend the envt with bindings for all the bound ids;
+ -- and *then* override with the polymorphic Ids from the signatures
+ -- That is the whole point of the "complete_it" stuff.
+ tcExtendEnvWithPat ids (tcExtendEnvWithPat sig_ids
+ complete_it
+ ) `thenTc` \ (mbinds', lie_req_rhss) ->
+ returnTc (mbinds', lie_req_pat `plusLIE` lie_req_rhss, names, mono_ids)
where
- sig_names = [name | (TySigInfo name _ _ _ _ _) <- tc_ty_sigs]
- sig_ids = [id | (TySigInfo _ id _ _ _ _) <- tc_ty_sigs]
-
- tc_mono_binds EmptyMonoBinds = returnTc (EmptyMonoBinds, emptyLIE)
-
- tc_mono_binds (AndMonoBinds mb1 mb2)
- = tc_mono_binds mb1 `thenTc` \ (mb1a, lie1) ->
- tc_mono_binds mb2 `thenTc` \ (mb2a, lie2) ->
- returnTc (AndMonoBinds mb1a mb2a, lie1 `plusLIE` lie2)
-
- tc_mono_binds (FunMonoBind name inf matches locn)
- = tcAddSrcLoc locn $
- tcLookupLocalValueOK "tc_mono_binds" name `thenNF_Tc` \ id ->
-
- -- Before checking the RHS, extend the envt with
- -- bindings for the *polymorphic* Ids from any type signatures
- tcExtendLocalValEnv sig_names sig_ids $
- tcMatchesFun name (idType id) matches `thenTc` \ (matches', lie) ->
-
- returnTc (FunMonoBind (TcId id) inf matches' locn, lie)
-
- tc_mono_binds bind@(PatMonoBind pat grhss_and_binds locn)
- = tcAddSrcLoc locn $
- tcPat pat `thenTc` \ (pat2, lie_pat, pat_ty) ->
- tcExtendLocalValEnv sig_names sig_ids $
- tcGRHSsAndBinds grhss_and_binds `thenTc` \ (grhss_and_binds2, lie, grhss_ty) ->
- tcAddErrCtxt (patMonoBindsCtxt bind) $
- unifyTauTy pat_ty grhss_ty `thenTc_`
- returnTc (PatMonoBind pat2 grhss_and_binds2 locn,
- plusLIE lie_pat lie)
+ sig_fn name = case maybeSig tc_ty_sigs name of
+ Nothing -> Nothing
+ Just (TySigInfo _ _ _ _ _ mono_id _ _) -> Just mono_id
+
+ sig_ids = listToBag [(name,poly_id) | TySigInfo name poly_id _ _ _ _ _ _ <- tc_ty_sigs]
+
+ kind = case is_rec of
+ Recursive -> boxedTypeKind -- Recursive, so no unboxed types
+ NonRecursive -> openTypeKind -- Non-recursive, so we permit unboxed types
+
+ tc_mb_pats EmptyMonoBinds
+ = returnTc (returnTc (EmptyMonoBinds, emptyLIE), emptyLIE, emptyBag, emptyBag, emptyLIE)
+
+ tc_mb_pats (AndMonoBinds mb1 mb2)
+ = tc_mb_pats mb1 `thenTc` \ (complete_it1, lie_req1, tvs1, ids1, lie_avail1) ->
+ tc_mb_pats mb2 `thenTc` \ (complete_it2, lie_req2, tvs2, ids2, lie_avail2) ->
+ let
+ complete_it = complete_it1 `thenTc` \ (mb1', lie1) ->
+ complete_it2 `thenTc` \ (mb2', lie2) ->
+ returnTc (AndMonoBinds mb1' mb2', lie1 `plusLIE` lie2)
+ in
+ returnTc (complete_it,
+ lie_req1 `plusLIE` lie_req2,
+ tvs1 `unionBags` tvs2,
+ ids1 `unionBags` ids2,
+ lie_avail1 `plusLIE` lie_avail2)
+
+ tc_mb_pats (FunMonoBind name inf matches locn)
+ = newTyVarTy boxedTypeKind `thenNF_Tc` \ pat_ty ->
+ tcVarPat sig_fn name pat_ty `thenTc` \ bndr_id ->
+ let
+ complete_it = tcAddSrcLoc locn $
+ tcMatchesFun name pat_ty matches `thenTc` \ (matches', lie) ->
+ returnTc (FunMonoBind (TcId bndr_id) inf matches' locn, lie)
+ in
+ returnTc (complete_it, emptyLIE, emptyBag, unitBag (name, bndr_id), emptyLIE)
+
+ tc_mb_pats bind@(PatMonoBind pat grhss_and_binds locn)
+ = tcAddSrcLoc locn $
+ newTyVarTy kind `thenNF_Tc` \ pat_ty ->
+ tcPat sig_fn pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+ let
+ complete_it = tcAddSrcLoc locn $
+ tcAddErrCtxt (patMonoBindsCtxt bind) $
+ tcGRHSsAndBinds grhss_and_binds pat_ty PatBindRhs `thenTc` \ (grhss_and_binds', lie) ->
+ returnTc (PatMonoBind pat' grhss_and_binds' locn, lie)
+ in
+ returnTc (complete_it, lie_req, tvs, ids, lie_avail)
\end{code}
%************************************************************************
%* *
%************************************************************************
-@tcSigs@ checks the signatures for validity, and returns a list of
-{\em freshly-instantiated} signatures. That is, the types are already
-split up, and have fresh type variables installed. All non-type-signature
-"RenamedSigs" are ignored.
-
-The @TcSigInfo@ contains @TcTypes@ because they are unified with
-the variable's type, and after that checked to see whether they've
-been instantiated.
-
-\begin{code}
-data TcSigInfo s
- = TySigInfo Name
- (TcIdBndr s) -- *Polymorphic* binder for this value...
- [TcTyVar s] (TcThetaType s) (TcTauType s)
- SrcLoc
-
-
-maybeSig :: [TcSigInfo s] -> Name -> Maybe (TcSigInfo s)
- -- Search for a particular signature
-maybeSig [] name = Nothing
-maybeSig (sig@(TySigInfo sig_name _ _ _ _ _) : sigs) name
- | name == sig_name = Just sig
- | otherwise = maybeSig sigs name
-\end{code}
-
-
-\begin{code}
-tcTySig :: (Name -> PragmaInfo)
- -> RenamedSig
- -> TcM s (TcSigInfo s)
-
-tcTySig prag_info_fn (Sig v ty src_loc)
- = tcAddSrcLoc src_loc $
- tcHsType ty `thenTc` \ sigma_ty ->
- tcInstSigType sigma_ty `thenNF_Tc` \ sigma_ty' ->
- let
- poly_id = mkUserId v sigma_ty' (prag_info_fn v)
- (tyvars', theta', tau') = splitSigmaTy sigma_ty'
- -- This splitSigmaTy tries hard to make sure that tau' is a type synonym
- -- wherever possible, which can improve interface files.
- in
- returnTc (TySigInfo v poly_id tyvars' theta' tau' src_loc)
-\end{code}
-
@checkSigMatch@ does the next step in checking signature matching.
The tau-type part has already been unified. What we do here is to
check that this unification has not over-constrained the (polymorphic)
\begin{code}
checkSigMatch []
- = returnTc (error "checkSigMatch")
+ = returnTc (error "checkSigMatch", emptyLIE)
-checkSigMatch tc_ty_sigs@( sig1@(TySigInfo _ id1 _ theta1 _ _) : all_sigs_but_first )
+checkSigMatch tc_ty_sigs@( sig1@(TySigInfo _ id1 _ theta1 _ _ _ _) : all_sigs_but_first )
= -- CHECK THAT THE SIGNATURE TYVARS AND TAU_TYPES ARE OK
-- Doesn't affect substitution
mapTc check_one_sig tc_ty_sigs `thenTc_`
-- ToDo: amplify
mapTc check_one_cxt all_sigs_but_first `thenTc_`
- returnTc theta1
+ returnTc (theta1, sig_lie)
where
sig1_dict_tys = mk_dict_tys theta1
n_sig1_dict_tys = length sig1_dict_tys
+ sig_lie = mkLIE [inst | TySigInfo _ _ _ _ _ _ inst _ <- tc_ty_sigs]
- check_one_cxt sig@(TySigInfo _ id _ theta _ src_loc)
+ check_one_cxt sig@(TySigInfo _ id _ theta _ _ _ src_loc)
= tcAddSrcLoc src_loc $
tcAddErrCtxt (sigContextsCtxt id1 id) $
checkTc (length this_sig_dict_tys == n_sig1_dict_tys)
where
this_sig_dict_tys = mk_dict_tys theta
- check_one_sig (TySigInfo name id sig_tyvars _ sig_tau src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (sigCtxt id) $
- checkSigTyVars sig_tyvars sig_tau
-
- mk_dict_tys theta = [mkDictTy c t | (c,t) <- theta]
-\end{code}
-
-
-@checkSigTyVars@ is used after the type in a type signature has been unified with
-the actual type found. It then checks that the type variables of the type signature
-are
- (a) still all type variables
- eg matching signature [a] against inferred type [(p,q)]
- [then a will be unified to a non-type variable]
-
- (b) still all distinct
- eg matching signature [(a,b)] against inferred type [(p,p)]
- [then a and b will be unified together]
-
-BUT ACTUALLY THESE FIRST TWO ARE FORCED BY USING DontBind TYVARS
-
- (c) not mentioned in the environment
- eg the signature for f in this:
+ check_one_sig (TySigInfo _ id sig_tyvars _ sig_tau _ _ src_loc)
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxtM (sigCtxt (quotes (ppr id)) sig_tau) $
+ checkSigTyVars sig_tyvars
- g x = ... where
- f :: a->[a]
- f y = [x,y]
-
- Here, f is forced to be monorphic by the free occurence of x.
-
-Before doing this, the substitution is applied to the signature type variable.
-
-\begin{code}
-checkSigTyVars :: [TcTyVar s] -- The original signature type variables
- -> TcType s -- signature type (for err msg)
- -> TcM s ()
-
-checkSigTyVars sig_tyvars sig_tau
- = tcGetGlobalTyVars `thenNF_Tc` \ globals ->
- let
- mono_tyvars = filter (`elementOfTyVarSet` globals) sig_tyvars
- in
- -- TEMPORARY FIX
- -- Until the final Bind-handling stuff is in, several type signatures in the same
- -- bindings group can cause the signature type variable from the different
- -- signatures to be unified. So we still need to zonk and check point (b).
- -- Remove when activating the new binding code
- mapNF_Tc zonkTcTyVar sig_tyvars `thenNF_Tc` \ sig_tys ->
- checkTcM (hasNoDups (map (getTyVar "checkSigTyVars") sig_tys))
- (zonkTcType sig_tau `thenNF_Tc` \ sig_tau' ->
- failTc (badMatchErr sig_tau sig_tau')
- ) `thenTc_`
-
-
- -- Check point (c)
- -- We want to report errors in terms of the original signature tyvars,
- -- ie sig_tyvars, NOT sig_tyvars'. sig_tys and sig_tyvars' correspond
- -- 1-1 with sig_tyvars, so we can just map back.
- checkTc (null mono_tyvars)
- (notAsPolyAsSigErr sig_tau mono_tyvars)
+ mk_dict_tys theta = [mkDictTy c ts | (c,ts) <- theta]
\end{code}
moving them into place as is done for type signatures.
\begin{code}
-tcPragmaSigs :: [RenamedSig] -- The pragma signatures
- -> TcM s (Name -> PragmaInfo, -- Maps name to the appropriate PragmaInfo
- TcHsBinds s,
+tcPragmaSigs :: [RenamedSig] -- The pragma signatures
+ -> TcM s (Name -> IdInfo, -- Maps name to the appropriate IdInfo
+ TcMonoBinds s,
LIE s)
--- For now we just deal with INLINE pragmas
-tcPragmaSigs sigs = returnTc (prag_fn, EmptyBinds, emptyLIE )
- where
- prag_fn name | any has_inline sigs = IWantToBeINLINEd
- | otherwise = NoPragmaInfo
- where
- has_inline (InlineSig n _) = (n == name)
- has_inline other = False
-
-
-{-
tcPragmaSigs sigs
- = mapAndUnzip3Tc tcPragmaSig sigs `thenTc` \ (names_w_id_infos, binds, lies) ->
+ = mapAndUnzip3Tc tcPragmaSig sigs `thenTc` \ (maybe_info_modifiers, binds, lies) ->
let
- name_to_info name = foldr ($) noIdInfo
- [info_fn | (n,info_fn) <- names_w_id_infos, n==name]
+ prag_fn name = foldr ($) noIdInfo [f | Just (n,f) <- maybe_info_modifiers, n==name]
in
- returnTc (name_to_info,
- foldr ThenBinds EmptyBinds binds,
- foldr plusLIE emptyLIE lies)
-\end{code}
-
-Here are the easy cases for tcPragmaSigs
-
-\begin{code}
-tcPragmaSig (DeforestSig name loc)
- = returnTc ((name, addDeforestInfo DoDeforest),EmptyBinds,emptyLIE)
-tcPragmaSig (InlineSig name loc)
- = returnTc ((name, addUnfoldInfo (iWantToBeINLINEd UnfoldAlways)), EmptyBinds, emptyLIE)
-tcPragmaSig (MagicUnfoldingSig name string loc)
- = returnTc ((name, addUnfoldInfo (mkMagicUnfolding string)), EmptyBinds, emptyLIE)
+ returnTc (prag_fn, andMonoBindList binds, plusLIEs lies)
\end{code}
The interesting case is for SPECIALISE pragmas. There are two forms.
a bit of overkill.
\begin{code}
+tcPragmaSig :: RenamedSig -> TcM s (Maybe (Name, IdInfo -> IdInfo), TcMonoBinds s, LIE s)
+tcPragmaSig (Sig _ _ _) = returnTc (Nothing, EmptyMonoBinds, emptyLIE)
+tcPragmaSig (SpecInstSig _ _) = returnTc (Nothing, EmptyMonoBinds, emptyLIE)
+
+tcPragmaSig (InlineSig name loc)
+ = returnTc (Just (name, setInlinePragInfo IWantToBeINLINEd), EmptyMonoBinds, emptyLIE)
+
+tcPragmaSig (NoInlineSig name loc)
+ = returnTc (Just (name, setInlinePragInfo IMustNotBeINLINEd), EmptyMonoBinds, emptyLIE)
+
tcPragmaSig (SpecSig name poly_ty maybe_spec_name src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (valSpecSigCtxt name spec_ty) $
+ = -- SPECIALISE f :: forall b. theta => tau = g
+ tcAddSrcLoc src_loc $
+ tcAddErrCtxt (valSpecSigCtxt name poly_ty) $
-- Get and instantiate its alleged specialised type
- tcHsType poly_ty `thenTc` \ sig_sigma ->
- tcInstSigType sig_sigma `thenNF_Tc` \ sig_ty ->
- let
- (sig_tyvars, sig_theta, sig_tau) = splitSigmaTy sig_ty
- origin = ValSpecOrigin name
- in
+ tcHsTcType poly_ty `thenTc` \ sig_ty ->
- -- Check that the SPECIALIZE pragma had an empty context
- checkTc (null sig_theta)
- (panic "SPECIALIZE non-empty context (ToDo: msg)") `thenTc_`
+ -- Check that f has a more general type, and build a RHS for
+ -- the spec-pragma-id at the same time
+ tcExpr (HsVar name) sig_ty `thenTc` \ (spec_expr, spec_lie) ->
- -- Get and instantiate the type of the id mentioned
- tcLookupLocalValueOK "tcPragmaSig" name `thenNF_Tc` \ main_id ->
- tcInstSigType [] (idType main_id) `thenNF_Tc` \ main_ty ->
- let
- (main_tyvars, main_rho) = splitForAllTy main_ty
- (main_theta,main_tau) = splitRhoTy main_rho
- main_arg_tys = mkTyVarTys main_tyvars
- in
+ case maybe_spec_name of
+ Nothing -> -- Just specialise "f" by building a SpecPragmaId binding
+ -- It is the thing that makes sure we don't prematurely
+ -- dead-code-eliminate the binding we are really interested in.
+ newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_id ->
+ returnTc (Nothing, VarMonoBind (TcId spec_id) spec_expr, spec_lie)
- -- Check that the specialised type is indeed an instance of
- -- the type of the main function.
- unifyTauTy sig_tau main_tau `thenTc_`
- checkSigTyVars sig_tyvars sig_tau `thenTc_`
-
- -- Check that the type variables of the polymorphic function are
- -- either left polymorphic, or instantiate to ground type.
- -- Also check that the overloaded type variables are instantiated to
- -- ground type; or equivalently that all dictionaries have ground type
- mapTc zonkTcType main_arg_tys `thenNF_Tc` \ main_arg_tys' ->
- zonkTcThetaType main_theta `thenNF_Tc` \ main_theta' ->
- tcAddErrCtxt (specGroundnessCtxt main_arg_tys')
- (checkTc (all isGroundOrTyVarTy main_arg_tys')) `thenTc_`
- tcAddErrCtxt (specContextGroundnessCtxt main_theta')
- (checkTc (and [isGroundTy ty | (_,ty) <- theta'])) `thenTc_`
-
- -- Build the SpecPragmaId; it is the thing that makes sure we
- -- don't prematurely dead-code-eliminate the binding we are really interested in.
- newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_pragma_id ->
-
- -- Build a suitable binding; depending on whether we were given
- -- a value (Maybe Name) to be used as the specialisation.
- case using of
- Nothing -> -- No implementation function specified
-
- -- Make a Method inst for the occurrence of the overloaded function
- newMethodWithGivenTy (OccurrenceOf name)
- (TcId main_id) main_arg_tys main_rho `thenNF_Tc` \ (lie, meth_id) ->
+ Just g_name -> -- Don't create a SpecPragmaId. Instead add some suitable IdIfo
+
+ panic "Can't handle SPECIALISE with a '= g' part"
- let
- pseudo_bind = VarMonoBind spec_pragma_id pseudo_rhs
- pseudo_rhs = mkHsTyLam sig_tyvars (HsVar (TcId meth_id))
- in
- returnTc (pseudo_bind, lie, \ info -> info)
+ {- Not yet. Because we're still in the TcType world we
+ can't really add to the SpecEnv of the Id. Instead we have to
+ record the information in a different sort of Sig, and add it to
+ the IdInfo after zonking.
- Just spec_name -> -- Use spec_name as the specialisation value ...
+ For now we just leave out this case
- -- Type check a simple occurrence of the specialised Id
- tcId spec_name `thenTc` \ (spec_body, spec_lie, spec_tau) ->
+ -- Get the type of f, and find out what types
+ -- f has to be instantiated at to give the signature type
+ tcLookupLocalValueOK "tcPragmaSig" name `thenNF_Tc` \ f_id ->
+ tcInstTcType (idType f_id) `thenNF_Tc` \ (f_tyvars, f_rho) ->
- -- Check that it has the correct type, and doesn't constrain the
- -- signature variables at all
- unifyTauTy sig_tau spec_tau `thenTc_`
- checkSigTyVars sig_tyvars sig_tau `thenTc_`
+ let
+ (sig_tyvars, sig_theta, sig_tau) = splitSigmaTy sig_ty
+ (f_theta, f_tau) = splitRhoTy f_rho
+ sig_tyvar_set = mkVarSet sig_tyvars
+ in
+ unifyTauTy sig_tau f_tau `thenTc_`
- -- Make a local SpecId to bind to applied spec_id
- newSpecId main_id main_arg_tys sig_ty `thenNF_Tc` \ local_spec_id ->
+ tcPolyExpr str (HsVar g_name) (mkSigmaTy sig_tyvars f_theta sig_tau) `thenTc` \ (_, _,
+ -}
- let
- spec_rhs = mkHsTyLam sig_tyvars spec_body
- spec_binds = VarMonoBind local_spec_id spec_rhs
- `AndMonoBinds`
- VarMonoBind spec_pragma_id (HsVar (TcId local_spec_id))
- spec_info = SpecInfo spec_tys (length main_theta) local_spec_id
- in
- returnTc ((name, addSpecInfo spec_info), spec_binds, spec_lie)
--}
+tcPragmaSig other = pprTrace "tcPragmaSig: ignoring" (ppr other) $
+ returnTc (Nothing, EmptyMonoBinds, emptyLIE)
\end{code}
\begin{code}
-patMonoBindsCtxt bind sty
- = hang (ptext SLIT("In a pattern binding:")) 4 (ppr sty bind)
+patMonoBindsCtxt bind
+ = hang (ptext SLIT("In a pattern binding:")) 4 (ppr bind)
-----------------------------------------------
-valSpecSigCtxt v ty sty
- = hang (ptext SLIT("In a SPECIALIZE pragma for a value:"))
- 4 (sep [(<>) (ppr sty v) (ptext SLIT(" ::")),
- ppr sty ty])
-
-
+valSpecSigCtxt v ty
+ = sep [ptext SLIT("In a SPECIALIZE pragma for a value:"),
+ nest 4 (ppr v <+> ptext SLIT(" ::") <+> ppr ty)]
-----------------------------------------------
-notAsPolyAsSigErr sig_tau mono_tyvars sty
+notAsPolyAsSigErr sig_tau mono_tyvars
= hang (ptext SLIT("A type signature is more polymorphic than the inferred type"))
- 4 (vcat [text "Some type variables in the inferred type can't be forall'd, namely:",
- interpp'SP sty mono_tyvars,
- ptext SLIT("Possible cause: the RHS mentions something subject to the monomorphism restriction")
- ])
+ 4 (vcat [text "Can't for-all the type variable(s)" <+>
+ pprQuotedList mono_tyvars,
+ text "in the type" <+> quotes (ppr sig_tau)
+ ])
-----------------------------------------------
-badMatchErr sig_ty inferred_ty sty
+badMatchErr sig_ty inferred_ty
= hang (ptext SLIT("Type signature doesn't match inferred type"))
- 4 (vcat [hang (ptext SLIT("Signature:")) 4 (ppr sty sig_ty),
- hang (ptext SLIT("Inferred :")) 4 (ppr sty inferred_ty)
+ 4 (vcat [hang (ptext SLIT("Signature:")) 4 (ppr sig_ty),
+ hang (ptext SLIT("Inferred :")) 4 (ppr inferred_ty)
])
-----------------------------------------------
-sigCtxt id sty
- = sep [ptext SLIT("When checking signature for"), ppr sty id]
-sigsCtxt ids sty
- = sep [ptext SLIT("When checking signature(s) for:"), interpp'SP sty ids]
+unboxedPatBindErr id
+ = ptext SLIT("variable in a lazy pattern binding has unboxed type: ")
+ <+> quotes (ppr id)
-----------------------------------------------
-sigContextsErr sty
+bindSigsCtxt ids
+ = ptext SLIT("When checking the type signature(s) for") <+> pprQuotedList ids
+
+-----------------------------------------------
+sigContextsErr
= ptext SLIT("Mismatched contexts")
-sigContextsCtxt s1 s2 sty
+sigContextsCtxt s1 s2
= hang (hsep [ptext SLIT("When matching the contexts of the signatures for"),
- ppr sty s1, ptext SLIT("and"), ppr sty s2])
+ quotes (ppr s1), ptext SLIT("and"), quotes (ppr s2)])
4 (ptext SLIT("(the signature contexts in a mutually recursive group should all be identical)"))
-----------------------------------------------
-specGroundnessCtxt
- = panic "specGroundnessCtxt"
-
---------------------------------------------
-specContextGroundnessCtxt -- err_ctxt dicts sty
- = panic "specContextGroundnessCtxt"
-{-
- = hang (
- sep [hsep [ptext SLIT("In the SPECIALIZE pragma for"), ppr sty name],
- hcat [ptext SLIT(" specialised to the type"), ppr sty spec_ty],
- pp_spec_id sty,
- ptext SLIT("... not all overloaded type variables were instantiated"),
- ptext SLIT("to ground types:")])
- 4 (vcat [hsep [ppr sty c, ppr sty t]
- | (c,t) <- map getDictClassAndType dicts])
- where
- (name, spec_ty, locn, pp_spec_id)
- = case err_ctxt of
- ValSpecSigCtxt n ty loc -> (n, ty, loc, \ x -> empty)
- ValSpecSpecIdCtxt n ty spec loc ->
- (n, ty, loc,
- \ sty -> hsep [ptext SLIT("... type of explicit id"), ppr sty spec])
--}
+unliftedBindErr flavour mbind
+ = hang (text flavour <+> ptext SLIT("bindings for unlifted types aren't allowed"))
+ 4 (ppr mbind)
+
+existentialExplode mbinds
+ = hang (vcat [text "My brain just exploded.",
+ text "I can't handle pattern bindings for existentially-quantified constructors.",
+ text "In the binding group"])
+ 4 (ppr mbinds)
\end{code}
-
-
-
-
projects / ghc-hetmet.git / blobdiff