\section[TcBinds]{TcBinds}
\begin{code}
-module TcBinds ( tcBindsAndThen, tcTopBindsAndThen,
- tcPragmaSigs, tcBindWithSigs ) where
+module TcBinds ( tcBindsAndThen, tcTopBinds,
+ tcSpecSigs, tcBindWithSigs ) where
#include "HsVersions.h"
-import {-# SOURCE #-} TcGRHSs ( tcGRHSsAndBinds )
+import {-# SOURCE #-} TcMatches ( tcGRHSs, tcMatchesFun )
import {-# SOURCE #-} TcExpr ( tcExpr )
-import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), InPat(..), StmtCtxt(..),
- collectMonoBinders, andMonoBindList, andMonoBinds
+import CmdLineOpts ( opt_NoMonomorphismRestriction )
+import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..),
+ Match(..), HsMatchContext(..),
+ collectMonoBinders, andMonoBinds
)
import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
-import TcHsSyn ( TcHsBinds, TcMonoBinds,
- TcIdOcc(..), TcIdBndr,
- tcIdType, zonkId
- )
+import TcHsSyn ( TcMonoBinds, TcId, zonkId, mkHsLet )
import TcMonad
-import Inst ( Inst, LIE, emptyLIE, mkLIE, plusLIE, plusLIEs, InstOrigin(..),
- newDicts, tyVarsOfInst, instToId,
+import Inst ( LIE, emptyLIE, mkLIE, plusLIE, InstOrigin(..),
+ newDicts, instToId
)
-import TcEnv ( tcExtendLocalValEnv, tcExtendEnvWithPat,
- tcLookupLocalValueOK,
- newSpecPragmaId,
- tcGetGlobalTyVars, tcExtendGlobalTyVars
+import TcEnv ( tcExtendLocalValEnv,
+ newSpecPragmaId, newLocalId
)
-import TcMatches ( tcMatchesFun )
-import TcSimplify ( tcSimplify, tcSimplifyAndCheck )
-import TcMonoType ( tcHsTcType, checkSigTyVars,
+import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyCheck, tcSimplifyRestricted, tcSimplifyToDicts )
+import TcMonoType ( tcHsSigType, checkSigTyVars,
TcSigInfo(..), tcTySig, maybeSig, sigCtxt
)
-import TcPat ( tcVarPat, tcPat )
+import TcPat ( tcPat )
import TcSimplify ( bindInstsOfLocalFuns )
-import TcType ( TcType, TcThetaType,
- TcTyVar,
- newTyVarTy, newTcTyVar, tcInstTcType,
- zonkTcType, zonkTcTypes, zonkTcThetaType )
+import TcType ( newTyVarTy, newTyVar,
+ zonkTcTyVarToTyVar
+ )
import TcUnify ( unifyTauTy, unifyTauTyLists )
-import Id ( mkUserId )
-import Var ( idType, idName, setIdInfo )
-import IdInfo ( IdInfo, noIdInfo, setInlinePragInfo, InlinePragInfo(..) )
-import Name ( Name )
+import CoreFVs ( idFreeTyVars )
+import Id ( mkLocalId, setInlinePragma )
+import Var ( idType, idName )
+import IdInfo ( InlinePragInfo(..) )
+import Name ( Name, getOccName, getSrcLoc )
+import NameSet
import Type ( mkTyVarTy, tyVarsOfTypes,
- splitSigmaTy, mkForAllTys, mkFunTys, getTyVar,
- mkDictTy, splitRhoTy, mkForAllTy, isUnLiftedType,
- isUnboxedType, openTypeKind,
- unboxedTypeKind, boxedTypeKind
+ mkForAllTys, mkFunTys, tyVarsOfType,
+ mkPredTy, mkForAllTy, isUnLiftedType,
+ unliftedTypeKind, liftedTypeKind, openTypeKind
)
-import Var ( TyVar, tyVarKind )
+import Var ( tyVarKind )
import VarSet
import Bag
import Util ( isIn )
-import BasicTypes ( TopLevelFlag(..), RecFlag(..) )
-import SrcLoc ( SrcLoc )
+import ListSetOps ( minusList )
+import Maybes ( maybeToBool )
+import BasicTypes ( TopLevelFlag(..), RecFlag(..), isNonRec, isNotTopLevel )
+import FiniteMap ( listToFM, lookupFM )
import Outputable
\end{code}
dictionaries, which we resolve at the module level.
\begin{code}
-tcTopBindsAndThen, tcBindsAndThen
- :: (RecFlag -> TcMonoBinds s -> thing -> thing) -- Combinator
+tcTopBinds :: RenamedHsBinds -> TcM ((TcMonoBinds, TcEnv), LIE)
+tcTopBinds binds
+ = tc_binds_and_then TopLevel glue binds $
+ tcGetEnv `thenNF_Tc` \ env ->
+ returnTc ((EmptyMonoBinds, env), emptyLIE)
+ where
+ glue is_rec binds1 (binds2, thing) = (binds1 `AndMonoBinds` binds2, thing)
+
+
+tcBindsAndThen
+ :: (RecFlag -> TcMonoBinds -> thing -> thing) -- Combinator
-> RenamedHsBinds
- -> TcM s (thing, LIE s)
- -> TcM s (thing, LIE s)
+ -> TcM (thing, LIE)
+ -> TcM (thing, LIE)
-tcTopBindsAndThen = tc_binds_and_then TopLevel
-tcBindsAndThen = tc_binds_and_then NotTopLevel
+tcBindsAndThen = tc_binds_and_then NotTopLevel
tc_binds_and_then top_lvl combiner EmptyBinds do_next
= do_next
do_next
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
+ = -- TYPECHECK THE SIGNATURES
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) ->
+ tcBindWithSigs top_lvl bind tc_ty_sigs
+ sigs is_rec `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
-- Extend the environment to bind the new polymorphic Ids
- tcExtendLocalValEnv (map idName poly_ids) poly_ids $
+ tcExtendLocalValEnv [(idName poly_id, poly_id) | poly_id <- poly_ids] $
-- Build bindings and IdInfos corresponding to user pragmas
- tcPragmaSigs sigs `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+ tcSpecSigs sigs `thenTc` \ (prag_binds, prag_lie) ->
-- Now do whatever happens next, in the augmented envt
do_next `thenTc` \ (thing, thing_lie) ->
-- Create specialisations of functions bound here
-- We want to keep non-recursive things non-recursive
- -- so that we desugar unboxed bindings correctly
+ -- so that we desugar unlifted 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,
+ -> returnTc (combiner Recursive (poly_binds `andMonoBinds` prag_binds) thing,
thing_lie `plusLIE` prag_lie `plusLIE` poly_lie)
(NotTopLevel, NonRecursive)
poly_ids `thenTc` \ (thing_lie', lie_binds) ->
returnTc (
- prag_info_fn,
combiner NonRecursive poly_binds $
combiner NonRecursive prag_binds $
combiner Recursive lie_binds $
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
-combiner function, appears below. Though it is perfectly well
-behaved, it cannot be typed by Haskell, because the recursive call is
-at a different type to the definition itself. There aren't too many
-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
-\end{pseudocode}
-
%************************************************************************
%* *
tcBindWithSigs
:: TopLevelFlag
-> RenamedMonoBinds
- -> [TcSigInfo s]
+ -> [TcSigInfo]
+ -> [RenamedSig] -- Used solely to get INLINE, NOINLINE sigs
-> RecFlag
- -> (Name -> IdInfo)
- -> TcM s (TcMonoBinds s, LIE s, [TcIdBndr s])
+ -> TcM (TcMonoBinds, LIE, [TcId])
-tcBindWithSigs top_lvl mbind tc_ty_sigs is_rec prag_info_fn
+tcBindWithSigs top_lvl mbind tc_ty_sigs inline_sigs is_rec
= recoverTc (
-- If typechecking the binds fails, then return with each
-- signature-less binder given type (forall a.a), to minimise subsequent
-- error messages
- newTcTyVar boxedTypeKind `thenNF_Tc` \ alpha_tv ->
+ newTyVar liftedTypeKind `thenNF_Tc` \ alpha_tv ->
let
forall_a_a = mkForAllTy alpha_tv (mkTyVarTy alpha_tv)
- binder_names = map fst (bagToList (collectMonoBinders mbind))
+ binder_names = 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 -- No signature
+ Nothing -> mkLocalId name forall_a_a -- No signature
in
returnTc (EmptyMonoBinds, emptyLIE, poly_ids)
- ) $
+ ) $
-- TYPECHECK THE BINDINGS
- tcMonoBinds mbind tc_ty_sigs is_rec `thenTc` \ (mbind', lie_req, binder_names, mono_ids) ->
-
+ tcMonoBinds mbind tc_ty_sigs is_rec `thenTc` \ (mbind', lie_req, binder_names, mono_ids) ->
let
- mono_id_tys = map idType mono_ids
+ tau_tvs = varSetElems (foldr (unionVarSet . tyVarsOfType . idType) emptyVarSet mono_ids)
in
- -- CHECK THAT THE SIGNATURES MATCH
- -- (must do this before getTyVarsToGen)
- checkSigMatch tc_ty_sigs `thenTc` \ (sig_theta, lie_avail) ->
+ -- GENERALISE
+ generalise binder_names mbind tau_tvs lie_req tc_ty_sigs
+ `thenTc` \ (tc_tyvars_to_gen, lie_free, dict_binds, dict_ids) ->
- -- 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_tys lie_req `thenNF_Tc` \ (tyvars_not_to_gen, tyvars_to_gen) ->
- -- DEAL WITH TYPE VARIABLE KINDS
- -- **** 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.
- --
- -- Also NB that tcSimplify takes zonked tyvars as its arg, hence we pass
- -- real_tyvars_to_gen
- in
+ -- ZONK THE GENERALISED TYPE VARIABLES TO REAL TyVars
+ -- This commits any unbound kind variables to boxed kind, by unification
+ -- It's important that the final quanfified type variables
+ -- are fully zonked, *including boxity*, because they'll be
+ -- included in the forall types of the polymorphic Ids.
+ -- At calls of these Ids we'll instantiate fresh type variables from
+ -- them, and we use their boxity then.
+ mapNF_Tc zonkTcTyVarToTyVar tc_tyvars_to_gen `thenNF_Tc` \ real_tyvars_to_gen ->
- -- 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
- -- 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
- 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 (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) ->
-
- -- 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.
- -- That's why we just use an ASSERT here.
+ -- ZONK THE Ids
+ -- It's important that the dict Ids are zonked, including the boxity set
+ -- in the previous step, because they are later used to form the type of
+ -- the polymorphic thing, and forall-types must be zonked so far as
+ -- their bound variables are concerned
+ mapNF_Tc zonkId dict_ids `thenNF_Tc` \ zonked_dict_ids ->
+ mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids ->
+ -- CHECK FOR BOGUS UNLIFTED BINDINGS
+ checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids `thenTc_`
- -- BUILD THE POLYMORPHIC RESULT IDs
- mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids ->
+ -- BUILD THE POLYMORPHIC RESULT IDs
let
exports = zipWith mk_export binder_names zonked_mono_ids
- dict_tys = map tcIdType dicts_bound
+ dict_tys = map idType zonked_dict_ids
+
+ inlines = mkNameSet [name | InlineSig name _ loc <- inline_sigs]
+ no_inlines = listToFM ([(name, IMustNotBeINLINEd False phase) | NoInlineSig name phase loc <- inline_sigs] ++
+ [(name, IMustNotBeINLINEd True phase) | InlineSig name phase loc <- inline_sigs, maybeToBool phase])
+ -- "INLINE n foo" means inline foo, but not until at least phase n
+ -- "NOINLINE n foo" means don't inline foo until at least phase n, and even
+ -- then only if it is small enough etc.
+ -- "NOINLINE foo" means don't inline foo ever, which we signal with a (IMustNotBeINLINEd Nothing)
+ -- See comments in CoreUnfold.blackListed for the Authorised Version
mk_export binder_name zonked_mono_id
= (tyvars,
- TcId (setIdInfo poly_id (prag_info_fn binder_name)),
- TcId zonked_mono_id)
+ attachNoInlinePrag no_inlines poly_id,
+ zonked_mono_id)
where
(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)
+ Nothing -> (real_tyvars_to_gen, new_poly_id)
- new_poly_id = mkUserId binder_name poly_ty
- poly_ty = mkForAllTys real_tyvars_to_gen_list
+ new_poly_id = mkLocalId binder_name poly_ty
+ poly_ty = mkForAllTys real_tyvars_to_gen
$ mkFunTys dict_tys
- $ idType (zonked_mono_id)
+ $ 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_`
+
+ traceTc (text "binding:" <+> ppr ((zonked_dict_ids, dict_binds),
+ exports, [idType poly_id | (_, poly_id, _) <- exports])) `thenTc_`
-- BUILD RESULTS
returnTc (
- AbsBinds real_tyvars_to_gen_list
- dicts_bound
- exports
- (dict_binds `andMonoBinds` mbind'),
- lie_free,
- [poly_id | (_, TcId poly_id, _) <- exports]
+ AbsBinds real_tyvars_to_gen
+ zonked_dict_ids
+ exports
+ inlines
+ (dict_binds `andMonoBinds` mbind'),
+ lie_free,
+ [poly_id | (_, poly_id, _) <- exports]
)
+
+attachNoInlinePrag no_inlines bndr
+ = case lookupFM no_inlines (idName bndr) of
+ Just prag -> bndr `setInlinePragma` prag
+ Nothing -> bndr
+
+checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids
+ = ASSERT( not (any ((== unliftedTypeKind) . tyVarKind) real_tyvars_to_gen) )
+ -- 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.
+ -- That's why we just use an ASSERT here.
+
+ -- Check that pattern-bound variables are not unlifted
+ (if or [ (idName id `elem` pat_binders) && isUnLiftedType (idType id)
+ | id <- zonked_mono_ids ] then
+ addErrTc (unliftedBindErr "Pattern" mbind)
+ else
+ returnTc ()
+ ) `thenTc_`
+
+ -- Unlifted bindings must be non-recursive,
+ -- not top level, non-polymorphic, and not pattern bound
+ if any (isUnLiftedType . idType) zonked_mono_ids then
+ checkTc (isNotTopLevel top_lvl)
+ (unliftedBindErr "Top-level" mbind) `thenTc_`
+ checkTc (isNonRec is_rec)
+ (unliftedBindErr "Recursive" mbind) `thenTc_`
+ checkTc (null real_tyvars_to_gen)
+ (unliftedBindErr "Polymorphic" mbind)
+ else
+ returnTc ()
+
where
- tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- tc_ty_sigs]
- is_unrestricted = isUnRestrictedGroup tysig_names mbind
+ pat_binders :: [Name]
+ pat_binders = collectMonoBinders (justPatBindings mbind EmptyMonoBinds)
-justPatBindings bind@(PatMonoBind _ _ _) binds = bind `andMonoBinds` binds
-justPatBindings (AndMonoBinds b1 b2) binds =
- justPatBindings b1 (justPatBindings b2 binds)
-justPatBindings other_bind binds = binds
+ justPatBindings bind@(PatMonoBind _ _ _) binds = bind `andMonoBinds` binds
+ justPatBindings (AndMonoBinds b1 b2) binds =
+ justPatBindings b1 (justPatBindings b2 binds)
+ justPatBindings other_bind binds = binds
\end{code}
+
Polymorphic recursion
~~~~~~~~~~~~~~~~~~~~~
The game plan for polymorphic recursion in the code above is
%* *
%************************************************************************
-@getTyVarsToGen@ decides what type variables generalise over.
+\begin{code}
+generalise_help doc tau_tvs lie_req sigs
+
+-----------------------
+ | null sigs
+ = -- INFERENCE CASE: Unrestricted group, no type signatures
+ tcSimplifyInfer doc
+ tau_tvs lie_req
+
+-----------------------
+ | otherwise
+ = -- CHECKING CASE: Unrestricted group, there are type signatures
+ -- Check signature contexts are empty
+ checkSigsCtxts sigs `thenTc` \ (sig_avails, sig_dicts) ->
+
+ -- Check that the needed dicts can be
+ -- expressed in terms of the signature ones
+ tcSimplifyInferCheck doc tau_tvs sig_avails lie_req `thenTc` \ (forall_tvs, lie_free, dict_binds) ->
+
+ -- Check that signature type variables are OK
+ checkSigsTyVars sigs `thenTc_`
+
+ returnTc (forall_tvs, lie_free, dict_binds, sig_dicts)
+
+generalise binder_names mbind tau_tvs lie_req sigs
+ | is_unrestricted -- UNRESTRICTED CASE
+ = generalise_help doc tau_tvs lie_req sigs
+
+ | otherwise -- RESTRICTED CASE
+ = -- Do a simplification to decide what type variables
+ -- are constrained. We can't just take the free vars
+ -- of lie_req because that'll have methods that may
+ -- incidentally mention entirely unconstrained variables
+ -- e.g. a call to f :: Eq a => a -> b -> b
+ -- Here, b is unconstrained. A good example would be
+ -- foo = f (3::Int)
+ -- We want to infer the polymorphic type
+ -- foo :: forall b. b -> b
+ generalise_help doc tau_tvs lie_req sigs `thenTc` \ (forall_tvs, lie_free, dict_binds, dict_ids) ->
+
+ -- Check signature contexts are empty
+ checkTc (null sigs || null dict_ids)
+ (restrictedBindCtxtErr binder_names) `thenTc_`
+
+ -- Identify constrained tyvars
+ let
+ constrained_tvs = varSetElems (tyVarsOfTypes (map idType dict_ids))
+ -- The dict_ids are fully zonked
+ final_forall_tvs = forall_tvs `minusList` constrained_tvs
+ in
+
+ -- Now simplify with exactly that set of tyvars
+ -- We have to squash those Methods
+ tcSimplifyRestricted doc final_forall_tvs [] lie_req `thenTc` \ (lie_free, binds) ->
+
+ returnTc (final_forall_tvs, lie_free, binds, [])
+
+ where
+ is_unrestricted | opt_NoMonomorphismRestriction = True
+ | otherwise = isUnRestrictedGroup tysig_names mbind
+
+ tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- sigs]
+
+ doc | null sigs = ptext SLIT("banding(s) for") <+> pprBinders binder_names
+ | otherwise = ptext SLIT("type signature(s) for") <+> pprBinders binder_names
+
+-----------------------
+ -- CHECK THAT ALL THE SIGNATURE CONTEXTS ARE UNIFIABLE
+ -- The type signatures on a mutually-recursive group of definitions
+ -- must all have the same context (or none).
+ --
+ -- We unify them because, with polymorphic recursion, their types
+ -- might not otherwise be related. This is a rather subtle issue.
+ -- ToDo: amplify
+checkSigsCtxts sigs@(TySigInfo _ id1 sig_tvs theta1 _ _ _ _ : other_sigs)
+ = mapTc_ check_one other_sigs `thenTc_`
+ if null theta1 then
+ returnTc ([], []) -- Non-overloaded type signatures
+ else
+ newDicts SignatureOrigin theta1 `thenNF_Tc` \ sig_dicts ->
+ let
+ -- The "sig_avails" 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)
+ sig_avails = sig_dicts ++ sig_meths
+ in
+ returnTc (sig_avails, map instToId sig_dicts)
+ where
+ sig1_dict_tys = map mkPredTy theta1
+ n_sig1_theta = length theta1
+ sig_meths = concat [insts | TySigInfo _ _ _ _ _ _ insts _ <- sigs]
+
+ check_one sig@(TySigInfo _ id _ theta _ _ _ src_loc)
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (sigContextsCtxt id1 id) $
+ checkTc (length theta == n_sig1_theta) sigContextsErr `thenTc_`
+ unifyTauTyLists sig1_dict_tys (map mkPredTy theta)
+
+checkSigsTyVars sigs = mapTc_ check_one sigs
+ where
+ check_one (TySigInfo _ id sig_tyvars sig_theta sig_tau _ _ src_loc)
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxtM (sigCtxt (sig_msg id) sig_tyvars sig_theta sig_tau) $
+ checkSigTyVars sig_tyvars (idFreeTyVars id)
+
+ sig_msg id = ptext SLIT("When checking the type signature for") <+> quotes (ppr id)
+\end{code}
+
+@getTyVarsToGen@ decides what type variables to generalise over.
For a "restricted group" -- see the monomorphism restriction
for a definition -- we bind no dictionaries, and
Another, more common, example is when there's a Method inst in
the LIE, whose type might very well involve non-overloaded
type variables.
+ [NOTE: Jan 2001: I don't understand the problem here so I'm doing
+ the simple thing instead]
(b) On the other hand, we mustn't generalise tyvars which are constrained,
because we are going to pass on out the unmodified LIE, with those
find which tyvars are constrained.
\begin{code}
-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 = tyVarsOfTypes zonked_mono_id_tys `minusVarSet` free_tyvars
- in
- if is_unrestricted
- then
- returnNF_Tc (emptyVarSet, tyvars_to_gen)
- else
- -- 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 (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}
isUnRestrictedGroup :: [Name] -- Signatures given for these
-> RenamedMonoBinds
-> Bool
is_elem v vs = isIn "isUnResMono" v vs
-isUnRestrictedGroup sigs (PatMonoBind (VarPatIn v) _ _) = v `is_elem` sigs
-isUnRestrictedGroup sigs (PatMonoBind other _ _) = False
+isUnRestrictedGroup sigs (PatMonoBind other _ _) = False
isUnRestrictedGroup sigs (VarMonoBind v _) = v `is_elem` sigs
-isUnRestrictedGroup sigs (FunMonoBind _ _ _ _) = True
+isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = any isUnRestrictedMatch matches ||
+ v `is_elem` sigs
isUnRestrictedGroup sigs (AndMonoBinds mb1 mb2) = isUnRestrictedGroup sigs mb1 &&
isUnRestrictedGroup sigs mb2
isUnRestrictedGroup sigs EmptyMonoBinds = True
-\end{code}
-
-@defaultUncommittedTyVar@ checks for generalisation over unboxed
-types, and defaults any TypeKind TyVars to BoxedTypeKind.
-
-\begin{code}
-defaultUncommittedTyVar tyvar
- | tyVarKind tyvar == openTypeKind
- = newTcTyVar boxedTypeKind `thenNF_Tc` \ boxed_tyvar ->
- unifyTauTy (mkTyVarTy tyvar) (mkTyVarTy boxed_tyvar) `thenTc_`
- returnTc boxed_tyvar
- | otherwise
- = returnTc tyvar
+isUnRestrictedMatch (Match _ [] Nothing _) = False -- No args, no signature
+isUnRestrictedMatch other = True -- Some args or a signature
\end{code}
\begin{code}
tcMonoBinds :: RenamedMonoBinds
- -> [TcSigInfo s]
+ -> [TcSigInfo]
-> RecFlag
- -> TcM s (TcMonoBinds s,
- LIE s, -- LIE required
+ -> TcM (TcMonoBinds,
+ LIE, -- LIE required
[Name], -- Bound names
- [TcIdBndr s]) -- Corresponding monomorphic bound things
+ [TcId]) -- 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)
+ id_list = bagToList ids
+ (names, mono_ids) = unzip id_list
+
+ -- This last defn is the key one:
+ -- extend the val envt with bindings for the
+ -- things bound in this group, overriding the monomorphic
+ -- ids with the polymorphic ones from the pattern
+ extra_val_env = case is_rec of
+ Recursive -> map mk_bind id_list
+ NonRecursive -> []
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,
+ -- *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) ->
+ --
+ -- There's a further wrinkle: we have to delay extending the environment
+ -- until after we've dealt with any pattern-bound signature type variables
+ -- Consider f (x::a) = ...f...
+ -- We're going to check that a isn't unified with anything in the envt,
+ -- so f itself had better not be! So we pass the envt binding f into
+ -- complete_it, which extends the actual envt in TcMatches.tcMatch, after
+ -- dealing with the signature tyvars
+
+ complete_it extra_val_env `thenTc` \ (mbinds', lie_req_rhss) ->
+
returnTc (mbinds', lie_req_pat `plusLIE` lie_req_rhss, names, mono_ids)
where
- 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]
+ -- This function is used when dealing with a LHS binder;
+ -- we make a monomorphic version of the Id.
+ -- We check for a type signature; if there is one, we use the mono_id
+ -- from the signature. This is how we make sure the tau part of the
+ -- signature actually maatches the type of the LHS; then tc_mb_pats
+ -- ensures the LHS and RHS have the same type
+
+ tc_pat_bndr name pat_ty
+ = case maybeSig tc_ty_sigs name of
+ Nothing
+ -> newLocalId (getOccName name) pat_ty (getSrcLoc name)
- kind = case is_rec of
- Recursive -> boxedTypeKind -- Recursive, so no unboxed types
- NonRecursive -> openTypeKind -- Non-recursive, so we permit unboxed types
+ Just (TySigInfo _ _ _ _ _ mono_id _ _)
+ -> tcAddSrcLoc (getSrcLoc name) $
+ unifyTauTy (idType mono_id) pat_ty `thenTc_`
+ returnTc mono_id
+
+ mk_bind (name, mono_id) = case maybeSig tc_ty_sigs name of
+ Nothing -> (name, mono_id)
+ Just (TySigInfo name poly_id _ _ _ _ _ _) -> (name, poly_id)
tc_mb_pats EmptyMonoBinds
- = returnTc (returnTc (EmptyMonoBinds, emptyLIE), emptyLIE, emptyBag, emptyBag, emptyLIE)
+ = returnTc (\ xve -> 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)
+ complete_it xve = complete_it1 xve `thenTc` \ (mb1', lie1) ->
+ complete_it2 xve `thenTc` \ (mb2', lie2) ->
+ returnTc (AndMonoBinds mb1' mb2', lie1 `plusLIE` lie2)
in
returnTc (complete_it,
lie_req1 `plusLIE` lie_req2,
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 ->
+ = newTyVarTy kind `thenNF_Tc` \ bndr_ty ->
+ tc_pat_bndr name bndr_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)
+ complete_it xve = tcAddSrcLoc locn $
+ tcMatchesFun xve name bndr_ty matches `thenTc` \ (matches', lie) ->
+ returnTc (FunMonoBind 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)
+ tc_mb_pats bind@(PatMonoBind pat grhss locn)
= tcAddSrcLoc locn $
- newTyVarTy kind `thenNF_Tc` \ pat_ty ->
- tcPat sig_fn pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+ newTyVarTy kind `thenNF_Tc` \ pat_ty ->
+
+ -- Now typecheck the pattern
+ -- We don't support binding fresh type variables in the
+ -- pattern of a pattern binding. For example, this is illegal:
+ -- (x::a, y::b) = e
+ -- whereas this is ok
+ -- (x::Int, y::Bool) = e
+ --
+ -- We don't check explicitly for this problem. Instead, we simply
+ -- type check the pattern with tcPat. If the pattern mentions any
+ -- fresh tyvars we simply get an out-of-scope type variable error
+ tcPat tc_pat_bndr 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)
+ complete_it xve = tcAddSrcLoc locn $
+ tcAddErrCtxt (patMonoBindsCtxt bind) $
+ tcExtendLocalValEnv xve $
+ tcGRHSs grhss pat_ty PatBindRhs `thenTc` \ (grhss', lie) ->
+ returnTc (PatMonoBind pat' grhss' locn, lie)
in
returnTc (complete_it, lie_req, tvs, ids, lie_avail)
-\end{code}
-
-%************************************************************************
-%* *
-\subsection{Signatures}
-%* *
-%************************************************************************
-
-@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)
-type variables of the original signature type.
-
-The error message here is somewhat unsatisfactory, but it'll do for
-now (ToDo).
-
-\begin{code}
-checkSigMatch []
- = returnTc (error "checkSigMatch", emptyLIE)
-
-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_`
-
- -- CHECK THAT ALL THE SIGNATURE CONTEXTS ARE UNIFIABLE
- -- The type signatures on a mutually-recursive group of definitions
- -- must all have the same context (or none).
- --
- -- We unify them because, with polymorphic recursion, their types
- -- might not otherwise be related. This is a rather subtle issue.
- -- ToDo: amplify
- mapTc check_one_cxt all_sigs_but_first `thenTc_`
- 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)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (sigContextsCtxt id1 id) $
- checkTc (length this_sig_dict_tys == n_sig1_dict_tys)
- sigContextsErr `thenTc_`
- unifyTauTyLists sig1_dict_tys this_sig_dict_tys
- where
- this_sig_dict_tys = mk_dict_tys theta
-
- check_one_sig (TySigInfo _ id sig_tyvars _ sig_tau _ _ src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxtM (sigCtxt (quotes (ppr id)) sig_tau) $
- checkSigTyVars sig_tyvars
-
- mk_dict_tys theta = [mkDictTy c ts | (c,ts) <- theta]
+ -- Figure out the appropriate kind for the pattern,
+ -- and generate a suitable type variable
+ kind = case is_rec of
+ Recursive -> liftedTypeKind -- Recursive, so no unlifted types
+ NonRecursive -> openTypeKind -- Non-recursive, so we permit unlifted types
\end{code}
%* *
%************************************************************************
-
-@tcPragmaSigs@ munches up the "signatures" that arise through *user*
+@tcSpecSigs@ munches up the specialisation "signatures" that arise through *user*
pragmas. It is convenient for them to appear in the @[RenamedSig]@
part of a binding because then the same machinery can be used for
moving them into place as is done for type signatures.
-\begin{code}
-tcPragmaSigs :: [RenamedSig] -- The pragma signatures
- -> TcM s (Name -> IdInfo, -- Maps name to the appropriate IdInfo
- TcMonoBinds s,
- LIE s)
+They look like this:
-tcPragmaSigs sigs
- = mapAndUnzip3Tc tcPragmaSig sigs `thenTc` \ (maybe_info_modifiers, binds, lies) ->
- let
- prag_fn name = foldr ($) noIdInfo [f | Just (n,f) <- maybe_info_modifiers, n==name]
- in
- returnTc (prag_fn, andMonoBindList binds, plusLIEs lies)
-\end{code}
-
-The interesting case is for SPECIALISE pragmas. There are two forms.
-Here's the first form:
\begin{verbatim}
f :: Ord a => [a] -> b -> b
{-# SPECIALIZE f :: [Int] -> b -> b #-}
Int, and will create a specialisation for @f@. After that, the
binding for @f*@ can be discarded.
-The second form is this:
-\begin{verbatim}
- f :: Ord a => [a] -> b -> b
- {-# SPECIALIZE f :: [Int] -> b -> b = g #-}
-\end{verbatim}
-
-Here @g@ is specified as a function that implements the specialised
-version of @f@. Suppose that g has type (a->b->b); that is, g's type
-is more general than that required. For this we generate
-\begin{verbatim}
- f@Int = /\b -> g Int b
- f* = f@Int
-\end{verbatim}
-
-Here @f@@Int@ is a SpecId, the specialised version of @f@. It inherits
-f's export status etc. @f*@ is a SpecPragmaId, as before, which just serves
-to prevent @f@@Int@ from being discarded prematurely. After specialisation,
-if @f@@Int@ is going to be used at all it will be used explicitly, so the simplifier can
-discard the f* binding.
-
-Actually, there is really only point in giving a SPECIALISE pragma on exported things,
-and the simplifer won't discard SpecIds for exporte things anyway, so maybe this is
-a bit of overkill.
+We used to have a form
+ {-# SPECIALISE f :: <type> = g #-}
+which promised that g implemented f at <type>, but we do that with
+a RULE now:
+ {-# SPECIALISE (f::<type) = g #-}
\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)
+tcSpecSigs :: [RenamedSig] -> TcM (TcMonoBinds, LIE)
+tcSpecSigs (SpecSig name poly_ty src_loc : sigs)
= -- SPECIALISE f :: forall b. theta => tau = g
tcAddSrcLoc src_loc $
tcAddErrCtxt (valSpecSigCtxt name poly_ty) $
-- Get and instantiate its alleged specialised type
- tcHsTcType poly_ty `thenTc` \ sig_ty ->
+ tcHsSigType poly_ty `thenTc` \ sig_ty ->
-- 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) ->
- 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)
-
- Just g_name -> -- Don't create a SpecPragmaId. Instead add some suitable IdIfo
-
- panic "Can't handle SPECIALISE with a '= g' part"
-
- {- 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.
-
- For now we just leave out this case
-
- -- 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) ->
-
- 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_`
-
- tcPolyExpr str (HsVar g_name) (mkSigmaTy sig_tyvars f_theta sig_tau) `thenTc` \ (_, _,
- -}
-
-tcPragmaSig other = pprTrace "tcPragmaSig: ignoring" (ppr other) $
- returnTc (Nothing, EmptyMonoBinds, emptyLIE)
+ -- Squeeze out any Methods (see comments with tcSimplifyToDicts)
+ tcSimplifyToDicts spec_lie `thenTc` \ (spec_dicts, spec_binds) ->
+
+ -- 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 ->
+
+ -- Do the rest and combine
+ tcSpecSigs sigs `thenTc` \ (binds_rest, lie_rest) ->
+ returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id (mkHsLet spec_binds spec_expr),
+ lie_rest `plusLIE` mkLIE spec_dicts)
+
+tcSpecSigs (other_sig : sigs) = tcSpecSigs sigs
+tcSpecSigs [] = returnTc (EmptyMonoBinds, emptyLIE)
\end{code}
-----------------------------------------------
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
- = hang (ptext SLIT("A type signature is more polymorphic than the inferred type"))
- 4 (vcat [text "Can't for-all the type variable(s)" <+>
- pprQuotedList mono_tyvars,
- text "in the type" <+> quotes (ppr sig_tau)
- ])
+ nest 4 (ppr v <+> dcolon <+> ppr ty)]
-----------------------------------------------
-badMatchErr sig_ty inferred_ty
- = hang (ptext SLIT("Type signature doesn't match inferred type"))
- 4 (vcat [hang (ptext SLIT("Signature:")) 4 (ppr sig_ty),
- hang (ptext SLIT("Inferred :")) 4 (ppr inferred_ty)
- ])
+sigContextsErr = ptext SLIT("Mismatched contexts")
------------------------------------------------
-unboxedPatBindErr id
- = ptext SLIT("variable in a lazy pattern binding has unboxed type: ")
- <+> quotes (ppr id)
-
------------------------------------------------
-bindSigsCtxt ids
- = ptext SLIT("When checking the type signature(s) for") <+> pprQuotedList ids
-
------------------------------------------------
-sigContextsErr
- = ptext SLIT("Mismatched contexts")
sigContextsCtxt s1 s2
= hang (hsep [ptext SLIT("When matching the contexts of the signatures for"),
quotes (ppr s1), ptext SLIT("and"), quotes (ppr s2)])
-----------------------------------------------
unliftedBindErr flavour mbind
- = hang (text flavour <+> ptext SLIT("bindings for unlifted types aren't allowed"))
+ = 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)
+
+-----------------------------------------------
+restrictedBindCtxtErr binder_names
+ = hang (ptext SLIT("Illegal overloaded type signature(s)"))
+ 4 (vcat [ptext SLIT("in a binding group for") <+> pprBinders binder_names,
+ ptext SLIT("that falls under the monomorphism restriction")])
+
+-- Used in error messages
+pprBinders bndrs = braces (pprWithCommas ppr bndrs)
\end{code}
projects / ghc-hetmet.git / blobdiff