\section[TcExpr]{Typecheck an expression}
\begin{code}
-module TcExpr ( tcApp, tcExpr, tcPolyExpr, tcId ) where
+module TcExpr ( tcApp, tcExpr, tcMonoExpr, tcPolyExpr, tcId ) where
#include "HsVersions.h"
import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..),
- HsBinds(..), Stmt(..), StmtCtxt(..)
+ HsMatchContext(..), mkMonoBind
)
import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds )
-import TcHsSyn ( TcExpr, TcRecordBinds,
- mkHsTyApp, mkHsLet, maybeBoxedPrimType
- )
+import TcHsSyn ( TcExpr, TcRecordBinds, mkHsLet )
import TcMonad
import BasicTypes ( RecFlag(..) )
-import Inst ( Inst, InstOrigin(..), OverloadedLit(..),
- LIE, emptyLIE, unitLIE, plusLIE, plusLIEs, newOverloadedLit,
- newMethod, instOverloadedFun, newDicts, instToId )
+import Inst ( InstOrigin(..),
+ LIE, mkLIE, emptyLIE, unitLIE, plusLIE, plusLIEs,
+ newOverloadedLit, newMethod, newIPDict,
+ newDicts,
+ instToId, tcInstId
+ )
import TcBinds ( tcBindsAndThen )
-import TcEnv ( tcInstId,
- tcLookupValue, tcLookupClassByKey,
- tcLookupValueByKey,
- tcExtendGlobalTyVars, tcLookupValueMaybe,
- tcLookupTyCon, tcLookupDataCon
+import TcEnv ( tcLookupClass, tcLookupGlobalId, tcLookupGlobal_maybe,
+ tcLookupTyCon, tcLookupDataCon, tcLookupId,
+ tcExtendGlobalTyVars, tcLookupSyntaxName
)
import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts )
-import TcMonoType ( tcHsType, checkSigTyVars, sigCtxt )
-import TcPat ( badFieldCon )
-import TcSimplify ( tcSimplifyAndCheck )
+import TcMonoType ( tcHsSigType, checkSigTyVars, sigCtxt )
+import TcPat ( badFieldCon, simpleHsLitTy )
+import TcSimplify ( tcSimplifyCheck, tcSimplifyIPs )
import TcType ( TcType, TcTauType,
- tcInstTyVars,
- tcInstTcType, tcSplitRhoTy,
- newTyVarTy, newTyVarTy_OpenKind, zonkTcType )
-
-import Class ( Class )
-import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType )
-import Id ( idType, recordSelectorFieldLabel,
- isRecordSelector,
- Id
+ tcInstTyVars, tcInstType,
+ newTyVarTy, newTyVarTys, zonkTcType )
+
+import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon )
+import Id ( idType, recordSelectorFieldLabel, isRecordSelector )
+import DataCon ( dataConFieldLabels, dataConSig,
+ dataConStrictMarks
)
-import DataCon ( dataConFieldLabels, dataConSig, dataConId )
+import Demand ( isMarkedStrict )
import Name ( Name )
-import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys,
- splitFunTy_maybe, splitFunTys, isNotUsgTy,
- mkTyConApp,
- splitForAllTys, splitRhoTy,
+import Type ( mkFunTy, mkAppTy, mkTyConTy,
+ splitFunTy_maybe, splitFunTys,
+ mkTyConApp, splitSigmaTy, mkClassPred,
isTauTy, tyVarsOfType, tyVarsOfTypes,
- isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe,
- boxedTypeKind, mkArrowKind,
+ isSigmaTy, splitAlgTyConApp, splitAlgTyConApp_maybe,
+ liftedTypeKind, openTypeKind, mkArrowKind,
tidyOpenType
)
-import Subst ( mkTopTyVarSubst, substTheta )
-import UsageSPUtils ( unannotTy )
-import VarSet ( elemVarSet, mkVarSet )
-import TyCon ( tyConDataCons )
-import TysPrim ( intPrimTy, charPrimTy, doublePrimTy,
- floatPrimTy, addrPrimTy
- )
-import TysWiredIn ( boolTy, charTy, stringTy )
-import PrelInfo ( ioTyCon_NAME )
-import TcUnify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy,
- unifyUnboxedTupleTy )
-import Unique ( cCallableClassKey, cReturnableClassKey,
- enumFromClassOpKey, enumFromThenClassOpKey,
- enumFromToClassOpKey, enumFromThenToClassOpKey,
- thenMClassOpKey, failMClassOpKey, returnMClassOpKey
+import TyCon ( TyCon, tyConTyVars )
+import Subst ( mkTopTyVarSubst, substTheta, substTy )
+import VarSet ( elemVarSet )
+import TysWiredIn ( boolTy, mkListTy, listTyCon )
+import TcUnify ( unifyTauTy, unifyFunTy, unifyListTy, unifyTupleTy )
+import PrelNames ( cCallableClassName,
+ cReturnableClassName,
+ enumFromName, enumFromThenName, negateName,
+ enumFromToName, enumFromThenToName,
+ thenMName, failMName, returnMName, ioTyConName
)
import Outputable
import Maybes ( maybeToBool )
import ListSetOps ( minusList )
import Util
+import CmdLineOpts
+import HscTypes ( TyThing(..) )
+
\end{code}
%************************************************************************
\begin{code}
tcExpr :: RenamedHsExpr -- Expession to type check
-> TcType -- Expected type (could be a polytpye)
- -> TcM s (TcExpr, LIE)
+ -> TcM (TcExpr, LIE)
-tcExpr expr ty | isForAllTy ty = -- Polymorphic case
- tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) ->
- returnTc (expr', lie)
+tcExpr expr ty | isSigmaTy ty = -- Polymorphic case
+ tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) ->
+ returnTc (expr', lie)
- | otherwise = -- Monomorphic case
- tcMonoExpr expr ty
+ | otherwise = -- Monomorphic case
+ tcMonoExpr expr ty
\end{code}
-- can be a polymorphic one.
tcPolyExpr :: RenamedHsExpr
-> TcType -- Expected type
- -> TcM s (TcExpr, LIE, -- Generalised expr with expected type, and LIE
+ -> TcM (TcExpr, LIE, -- Generalised expr with expected type, and LIE
TcExpr, TcTauType, LIE) -- Same thing, but instantiated; tau-type returned
tcPolyExpr arg expected_arg_ty
-- To ensure that the forall'd type variables don't get unified with each
-- other or any other types, we make fresh copy of the alleged type
- tcInstTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) ->
+ tcInstType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_theta, sig_tau) ->
let
- (sig_theta, sig_tau) = splitRhoTy sig_rho
+ free_tvs = tyVarsOfType expected_arg_ty
in
-- Type-check the arg and unify with expected type
tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) ->
-- Conclusion: include the free vars of the expected arg type in the
-- list of "free vars" for the signature check.
- tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) $
- tcAddErrCtxtM (sigCtxt sig_msg expected_arg_ty) $
-
- checkSigTyVars sig_tyvars `thenTc` \ zonked_sig_tyvars ->
+ tcExtendGlobalTyVars free_tvs $
+ tcAddErrCtxtM (sigCtxt sig_msg sig_tyvars sig_theta sig_tau) $
- newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) ->
- -- ToDo: better origin
- tcSimplifyAndCheck
- (text "tcPolyExpr")
- (mkVarSet zonked_sig_tyvars)
+ newDicts SignatureOrigin sig_theta `thenNF_Tc` \ sig_dicts ->
+ tcSimplifyCheck
+ (text "the type signature of an expression")
+ sig_tyvars
sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) ->
+ checkSigTyVars sig_tyvars free_tvs `thenTc` \ zonked_sig_tyvars ->
+
let
-- This HsLet binds any Insts which came out of the simplification.
-- It's a bit out of place here, but using AbsBind involves inventing
-- a couple of new names which seems worse.
generalised_arg = TyLam zonked_sig_tyvars $
- DictLam dict_ids $
+ DictLam (map instToId sig_dicts) $
mkHsLet inst_binds $
arg'
in
returnTc ( generalised_arg, free_insts,
arg', sig_tau, lie_arg )
where
- sig_msg ty = ptext SLIT("In an expression with expected type:") <+> ppr ty
+ sig_msg = ptext SLIT("When checking an expression type signature")
\end{code}
%************************************************************************
\begin{code}
tcMonoExpr :: RenamedHsExpr -- Expession to type check
- -> TcTauType -- Expected type (could be a type variable)
- -> TcM s (TcExpr, LIE)
+ -> TcTauType -- Expected type (could be a type variable)
+ -> TcM (TcExpr, LIE)
tcMonoExpr (HsVar name) res_ty
= tcId name `thenNF_Tc` \ (expr', lie, id_ty) ->
returnTc (expr', lie)
\end{code}
-%************************************************************************
-%* *
-\subsection{Literals}
-%* *
-%************************************************************************
-
-Overloaded literals.
-
\begin{code}
-tcMonoExpr (HsLit (HsInt i)) res_ty
- = newOverloadedLit (LiteralOrigin (HsInt i))
- (OverloadedIntegral i)
- res_ty `thenNF_Tc` \ stuff ->
- returnTc stuff
-
-tcMonoExpr (HsLit (HsFrac f)) res_ty
- = newOverloadedLit (LiteralOrigin (HsFrac f))
- (OverloadedFractional f)
- res_ty `thenNF_Tc` \ stuff ->
- returnTc stuff
-
-
-tcMonoExpr (HsLit lit@(HsLitLit s)) res_ty
- = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
- newDicts (LitLitOrigin (_UNPK_ s))
- [(cCallableClass, [res_ty])] `thenNF_Tc` \ (dicts, _) ->
- returnTc (HsLitOut lit res_ty, dicts)
-\end{code}
-
-Primitive literals:
-
-\begin{code}
-tcMonoExpr (HsLit lit@(HsCharPrim c)) res_ty
- = unifyTauTy res_ty charPrimTy `thenTc_`
- returnTc (HsLitOut lit charPrimTy, emptyLIE)
-
-tcMonoExpr (HsLit lit@(HsStringPrim s)) res_ty
- = unifyTauTy res_ty addrPrimTy `thenTc_`
- returnTc (HsLitOut lit addrPrimTy, emptyLIE)
-
-tcMonoExpr (HsLit lit@(HsIntPrim i)) res_ty
- = unifyTauTy res_ty intPrimTy `thenTc_`
- returnTc (HsLitOut lit intPrimTy, emptyLIE)
-
-tcMonoExpr (HsLit lit@(HsFloatPrim f)) res_ty
- = unifyTauTy res_ty floatPrimTy `thenTc_`
- returnTc (HsLitOut lit floatPrimTy, emptyLIE)
-
-tcMonoExpr (HsLit lit@(HsDoublePrim d)) res_ty
- = unifyTauTy res_ty doublePrimTy `thenTc_`
- returnTc (HsLitOut lit doublePrimTy, emptyLIE)
-\end{code}
-
-Unoverloaded literals:
-
-\begin{code}
-tcMonoExpr (HsLit lit@(HsChar c)) res_ty
- = unifyTauTy res_ty charTy `thenTc_`
- returnTc (HsLitOut lit charTy, emptyLIE)
-
-tcMonoExpr (HsLit lit@(HsString str)) res_ty
- = unifyTauTy res_ty stringTy `thenTc_`
- returnTc (HsLitOut lit stringTy, emptyLIE)
+tcMonoExpr (HsIPVar name) res_ty
+ = newIPDict (IPOcc name) name res_ty `thenNF_Tc` \ ip ->
+ returnNF_Tc (HsIPVar (instToId ip), unitLIE ip)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcMonoExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go
- = tcMonoExpr expr res_ty
-
--- perform the negate *before* overloading the integer, since the case
--- of minBound on Ints fails otherwise. Could be done elsewhere, but
--- convenient to do it here.
+tcMonoExpr (HsLit lit) res_ty = tcLit lit res_ty
+tcMonoExpr (HsOverLit lit) res_ty = newOverloadedLit (LiteralOrigin lit) lit res_ty
+tcMonoExpr (HsPar expr) res_ty = tcMonoExpr expr res_ty
-tcMonoExpr (NegApp (HsLit (HsInt i)) neg) res_ty
- = tcMonoExpr (HsLit (HsInt (-i))) res_ty
-
-tcMonoExpr (NegApp expr neg) res_ty
- = tcMonoExpr (HsApp neg expr) res_ty
+tcMonoExpr (NegApp expr) res_ty
+ = tcLookupSyntaxName negateName `thenNF_Tc` \ neg ->
+ tcMonoExpr (HsApp (HsVar neg) expr) res_ty
tcMonoExpr (HsLam match) res_ty
= tcMatchLambda match res_ty `thenTc` \ (match',lie) ->
later use.
\begin{code}
-tcMonoExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty) res_ty
+tcMonoExpr (HsCCall lbl args may_gc is_asm ignored_fake_result_ty) res_ty
= -- Get the callable and returnable classes.
- tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
- tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass ->
- tcLookupTyCon ioTyCon_NAME `thenNF_Tc` \ ioTyCon ->
+ tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass ->
+ tcLookupClass cReturnableClassName `thenNF_Tc` \ cReturnableClass ->
+ tcLookupTyCon ioTyConName `thenNF_Tc` \ ioTyCon ->
let
new_arg_dict (arg, arg_ty)
= newDicts (CCallOrigin (_UNPK_ lbl) (Just arg))
- [(cCallableClass, [arg_ty])] `thenNF_Tc` \ (arg_dicts, _) ->
+ [mkClassPred cCallableClass [arg_ty]] `thenNF_Tc` \ arg_dicts ->
returnNF_Tc arg_dicts -- Actually a singleton bag
result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -}
tv_idxs | n_args == 0 = []
| otherwise = [1..n_args]
in
- mapNF_Tc (\ _ -> newTyVarTy_OpenKind) tv_idxs `thenNF_Tc` \ arg_tys ->
+ newTyVarTys (length tv_idxs) openTypeKind `thenNF_Tc` \ arg_tys ->
tcMonoExprs args arg_tys `thenTc` \ (args', args_lie) ->
- -- The argument types can be unboxed or boxed; the result
- -- type must, however, be boxed since it's an argument to the IO
+ -- The argument types can be unlifted or lifted; the result
+ -- type must, however, be lifted since it's an argument to the IO
-- type constructor.
- newTyVarTy boxedTypeKind `thenNF_Tc` \ result_ty ->
+ newTyVarTy liftedTypeKind `thenNF_Tc` \ result_ty ->
let
io_result_ty = mkTyConApp ioTyCon [result_ty]
- [ioDataCon] = tyConDataCons ioTyCon
in
unifyTauTy res_ty io_result_ty `thenTc_`
-- Construct the extra insts, which encode the
-- constraints on the argument and result types.
mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s ->
- newDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) ->
- returnTc (HsApp (HsVar (dataConId ioDataCon) `TyApp` [result_ty])
- (CCall lbl args' may_gc is_asm result_ty),
- -- do the wrapping in the newtype constructor here
- foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie)
+ newDicts result_origin [mkClassPred cReturnableClass [result_ty]] `thenNF_Tc` \ ccres_dict ->
+ returnTc (HsCCall lbl args' may_gc is_asm io_result_ty,
+ mkLIE (ccres_dict ++ concat ccarg_dicts_s) `plusLIE` args_lie)
\end{code}
\begin{code}
-tcMonoExpr (HsSCC label expr) res_ty
+tcMonoExpr (HsSCC lbl expr) res_ty
= tcMonoExpr expr res_ty `thenTc` \ (expr', lie) ->
- returnTc (HsSCC label expr', lie)
+ returnTc (HsSCC lbl expr', lie)
tcMonoExpr (HsLet binds expr) res_ty
= tcBindsAndThen
where
tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) ->
returnTc (expr', lie)
- combiner is_rec bind expr = HsLet (MonoBind bind [] is_rec) expr
+ combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr
tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty
= tcAddSrcLoc src_loc $
= tcAddErrCtxt (listCtxt expr) $
tcMonoExpr expr elt_ty
-tcMonoExpr (ExplicitTuple exprs boxed) res_ty
- = (if boxed
- then unifyTupleTy (length exprs) res_ty
- else unifyUnboxedTupleTy (length exprs) res_ty
- ) `thenTc` \ arg_tys ->
+tcMonoExpr (ExplicitTuple exprs boxity) res_ty
+ = unifyTupleTy boxity (length exprs) res_ty `thenTc` \ arg_tys ->
mapAndUnzipTc (\ (expr, arg_ty) -> tcMonoExpr expr arg_ty)
(exprs `zip` arg_tys) -- we know they're of equal length.
`thenTc` \ (exprs', lies) ->
- returnTc (ExplicitTuple exprs' boxed, plusLIEs lies)
+ returnTc (ExplicitTuple exprs' boxity, plusLIEs lies)
-tcMonoExpr (RecordCon con_name rbinds) res_ty
- = tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) ->
+tcMonoExpr expr@(RecordCon con_name rbinds) res_ty
+ = tcAddErrCtxt (recordConCtxt expr) $
+ tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) ->
let
(_, record_ty) = splitFunTys con_tau
+ (tycon, ty_args, _) = splitAlgTyConApp record_ty
in
- -- Con is syntactically constrained to be a data constructor
ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) )
unifyTauTy res_ty record_ty `thenTc_`
-- Check that the record bindings match the constructor
- tcLookupDataCon con_name `thenTc` \ (data_con, _, _) ->
+ -- con_name is syntactically constrained to be a data constructor
+ tcLookupDataCon con_name `thenTc` \ data_con ->
let
bad_fields = badFields rbinds data_con
in
else
-- Typecheck the record bindings
- tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+ tcRecordBinds tycon ty_args rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+
+ let
+ (missing_s_fields, missing_fields) = missingFields rbinds data_con
+ in
+ checkTcM (null missing_s_fields)
+ (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_`
+ returnNF_Tc ()) `thenNF_Tc_`
+ doptsTc Opt_WarnMissingFields `thenNF_Tc` \ warn ->
+ checkTcM (not (warn && not (null missing_fields)))
+ (mapNF_Tc ((warnTc True) . missingFieldCon con_name) missing_fields `thenNF_Tc_`
+ returnNF_Tc ()) `thenNF_Tc_`
returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie)
-
-- The main complication with RecordUpd is that we need to explicitly
-- handle the *non-updated* fields. Consider:
--
--
-- All this is done in STEP 4 below.
-tcMonoExpr (RecordUpd record_expr rbinds) res_ty
- = tcAddErrCtxt recordUpdCtxt $
+tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty
+ = tcAddErrCtxt (recordUpdCtxt expr) $
-- STEP 0
-- Check that the field names are really field names
let
field_names = [field_name | (field_name, _, _) <- rbinds]
in
- mapNF_Tc tcLookupValueMaybe field_names `thenNF_Tc` \ maybe_sel_ids ->
+ mapNF_Tc tcLookupGlobal_maybe field_names `thenNF_Tc` \ maybe_sel_ids ->
let
- bad_guys = [field_name | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids,
- case maybe_sel_id of
- Nothing -> True
- Just sel_id -> not (isRecordSelector sel_id)
+ bad_guys = [ addErrTc (notSelector field_name)
+ | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids,
+ case maybe_sel_id of
+ Just (AnId sel_id) -> not (isRecordSelector sel_id)
+ other -> True
]
in
- mapNF_Tc (addErrTc . notSelector) bad_guys `thenTc_`
- if not (null bad_guys) then
- failTc
- else
+ checkTcM (null bad_guys) (listNF_Tc bad_guys `thenNF_Tc_` failTc) `thenTc_`
-- STEP 1
-- Figure out the tycon and data cons from the first field name
let
- (Just sel_id : _) = maybe_sel_ids
- (_, tau) = ASSERT( isNotUsgTy (idType sel_id) )
- splitForAllTys (idType sel_id)
+ (Just (AnId sel_id) : _) = maybe_sel_ids
+ (_, _, tau) = splitSigmaTy (idType sel_id) -- Selectors can be overloaded
+ -- when the data type has a context
Just (data_ty, _) = splitFunTy_maybe tau -- Must succeed since sel_id is a selector
- (tycon, _, data_cons) = splitAlgTyConApp data_ty
- (con_tyvars, theta, _, _, _, _) = dataConSig (head data_cons)
+ (tycon, _, data_cons) = splitAlgTyConApp data_ty
+ (con_tyvars, _, _, _, _, _) = dataConSig (head data_cons)
in
tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) ->
result_record_ty = mkTyConApp tycon result_inst_tys
in
unifyTauTy res_ty result_record_ty `thenTc_`
- tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+ tcRecordBinds tycon result_inst_tys rbinds `thenTc` \ (rbinds', rbinds_lie) ->
-- STEP 4
-- Use the un-updated fields to find a vector of booleans saying
mk_inst_ty (tyvar, result_inst_ty)
| tyvar `elemVarSet` common_tyvars = returnNF_Tc result_inst_ty -- Same as result type
- | otherwise = newTyVarTy boxedTypeKind -- Fresh type
+ | otherwise = newTyVarTy liftedTypeKind -- Fresh type
in
mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys ->
inst_env = mkTopTyVarSubst tyvars result_inst_tys
theta' = substTheta inst_env theta
in
- newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) ->
+ newDicts RecordUpdOrigin theta' `thenNF_Tc` \ dicts ->
-- Phew!
- returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds',
- con_lie `plusLIE` record_lie `plusLIE` rbinds_lie)
+ returnTc (RecordUpdOut record_expr' result_record_ty (map instToId dicts) rbinds',
+ mkLIE dicts `plusLIE` record_lie `plusLIE` rbinds_lie)
tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty
= unifyListTy res_ty `thenTc` \ elt_ty ->
tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) ->
- tcLookupValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id ->
+ tcLookupGlobalId enumFromName `thenNF_Tc` \ sel_id ->
newMethod (ArithSeqOrigin seq)
- sel_id [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) ->
+ sel_id [elt_ty] `thenNF_Tc` \ enum_from ->
- returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'),
- lie1 `plusLIE` lie2)
+ returnTc (ArithSeqOut (HsVar (instToId enum_from)) (From expr'),
+ lie1 `plusLIE` unitLIE enum_from)
tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty
= tcAddErrCtxt (arithSeqCtxt in_expr) $
- unifyListTy res_ty `thenTc` \ elt_ty ->
- tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
- tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
- tcLookupValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id ->
- newMethod (ArithSeqOrigin seq)
- sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) ->
+ unifyListTy res_ty `thenTc` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
+ tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
+ tcLookupGlobalId enumFromThenName `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_then ->
- returnTc (ArithSeqOut (HsVar enum_from_then_id)
- (FromThen expr1' expr2'),
- lie1 `plusLIE` lie2 `plusLIE` lie3)
+ returnTc (ArithSeqOut (HsVar (instToId enum_from_then))
+ (FromThen expr1' expr2'),
+ lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_then)
tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty
= tcAddErrCtxt (arithSeqCtxt in_expr) $
- unifyListTy res_ty `thenTc` \ elt_ty ->
- tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
- tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
- tcLookupValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id ->
- newMethod (ArithSeqOrigin seq)
- sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) ->
+ unifyListTy res_ty `thenTc` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
+ tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
+ tcLookupGlobalId enumFromToName `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ enum_from_to ->
- returnTc (ArithSeqOut (HsVar enum_from_to_id)
+ returnTc (ArithSeqOut (HsVar (instToId enum_from_to))
(FromTo expr1' expr2'),
- lie1 `plusLIE` lie2 `plusLIE` lie3)
+ lie1 `plusLIE` lie2 `plusLIE` unitLIE enum_from_to)
tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty
= tcAddErrCtxt (arithSeqCtxt in_expr) $
- unifyListTy res_ty `thenTc` \ elt_ty ->
- tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
- tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
- tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) ->
- tcLookupValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id ->
- newMethod (ArithSeqOrigin seq)
- sel_id [elt_ty] `thenNF_Tc` \ (lie4, eft_id) ->
-
- returnTc (ArithSeqOut (HsVar eft_id)
- (FromThenTo expr1' expr2' expr3'),
- lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4)
+ unifyListTy res_ty `thenTc` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
+ tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
+ tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) ->
+ tcLookupGlobalId enumFromThenToName `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq) sel_id [elt_ty] `thenNF_Tc` \ eft ->
+
+ returnTc (ArithSeqOut (HsVar (instToId eft))
+ (FromThenTo expr1' expr2' expr3'),
+ lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` unitLIE eft)
\end{code}
%************************************************************************
\begin{code}
tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty
= tcSetErrCtxt (exprSigCtxt in_expr) $
- tcHsType poly_ty `thenTc` \ sig_tc_ty ->
+ tcHsSigType poly_ty `thenTc` \ sig_tc_ty ->
- if not (isForAllTy sig_tc_ty) then
+ if not (isSigmaTy sig_tc_ty) then
-- Easy case
unifyTauTy sig_tc_ty res_ty `thenTc_`
tcMonoExpr expr sig_tc_ty
-- If everything is ok, return the stuff unchanged, except for
-- the effect of any substutions etc. We simply discard the
- -- result of the tcSimplifyAndCheck (inside tcPolyExpr), except for any default
+ -- result of the tcSimplifyCheck (inside tcPolyExpr), except for any default
-- resolution it may have done, which is recorded in the
-- substitution.
returnTc (expr, lie)
\end{code}
-Typecheck expression which in most cases will be an Id.
+Implicit Parameter bindings.
\begin{code}
-tcExpr_id :: RenamedHsExpr
- -> TcM s (TcExpr,
- LIE,
- TcType)
-tcExpr_id id_expr
- = case id_expr of
- HsVar name -> tcId name `thenNF_Tc` \ stuff ->
- returnTc stuff
- other -> newTyVarTy_OpenKind `thenNF_Tc` \ id_ty ->
- tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) ->
- returnTc (id_expr', lie_id, id_ty)
+tcMonoExpr (HsWith expr binds) res_ty
+ = tcMonoExpr expr res_ty `thenTc` \ (expr', expr_lie) ->
+ mapAndUnzipTc tcIPBind binds `thenTc` \ (pairs, bind_lies) ->
+
+ -- If the binding binds ?x = E, we must now
+ -- discharge any ?x constraints in expr_lie
+ tcSimplifyIPs (map fst pairs) expr_lie `thenTc` \ (expr_lie', dict_binds) ->
+ let
+ binds' = [(instToId ip, rhs) | (ip,rhs) <- pairs]
+ expr'' = HsLet (mkMonoBind dict_binds [] Recursive) expr'
+ in
+ returnTc (HsWith expr'' binds', expr_lie' `plusLIE` plusLIEs bind_lies)
+
+tcIPBind (name, expr)
+ = newTyVarTy openTypeKind `thenTc` \ ty ->
+ tcGetSrcLoc `thenTc` \ loc ->
+ newIPDict (IPBind name) name ty `thenNF_Tc` \ ip ->
+ tcMonoExpr expr ty `thenTc` \ (expr', lie) ->
+ returnTc ((ip, expr'), lie)
\end{code}
%************************************************************************
tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
-> TcType -- Expected result type of application
- -> TcM s (TcExpr, [TcExpr], -- Translated fun and args
+ -> TcM (TcExpr, [TcExpr], -- Translated fun and args
LIE)
tcApp fun args res_ty
-- Check that the result type doesn't have any nested for-alls.
-- For example, a "build" on its own is no good; it must be applied to something.
checkTc (isTauTy actual_result_ty)
- (lurkingRank2Err fun fun_ty) `thenTc_`
+ (lurkingRank2Err fun actual_result_ty) `thenTc_`
returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s)
split_fun_ty :: TcType -- The type of the function
-> Int -- Number of arguments
- -> TcM s ([TcType], -- Function argument types
+ -> TcM ([TcType], -- Function argument types
TcType) -- Function result types
split_fun_ty fun_ty 0
\begin{code}
tcArg :: RenamedHsExpr -- The function (for error messages)
-> (RenamedHsExpr, TcType, Int) -- Actual argument and expected arg type
- -> TcM s (TcExpr, LIE) -- Resulting argument and LIE
+ -> TcM (TcExpr, LIE) -- Resulting argument and LIE
tcArg the_fun (arg, expected_arg_ty, arg_no)
= tcAddErrCtxt (funAppCtxt the_fun arg arg_no) $
%* *
%************************************************************************
-Between the renamer and the first invocation of the UsageSP inference,
-identifiers read from interface files will have usage information in
-their types, whereas other identifiers will not. The unannotTy here
-in @tcId@ prevents this information from pointlessly propagating
-further prior to the first usage inference.
-
\begin{code}
-tcId :: Name -> NF_TcM s (TcExpr, LIE, TcType)
-
-tcId name
- = -- Look up the Id and instantiate its type
- tcLookupValueMaybe name `thenNF_Tc` \ maybe_local ->
-
- case maybe_local of
- Just tc_id -> instantiate_it (OccurrenceOf tc_id) (HsVar tc_id) (unannotTy (idType tc_id))
+tcId :: Name -> NF_TcM (TcExpr, LIE, TcType)
+tcId name -- Look up the Id and instantiate its type
+ = tcLookupId name `thenNF_Tc` \ id ->
+ tcInstId id
+\end{code}
- Nothing -> tcLookupValue name `thenNF_Tc` \ id ->
- tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) ->
- instantiate_it2 (OccurrenceOf id) (HsVar id) tyvars theta tau
+Typecheck expression which in most cases will be an Id.
- where
- -- The instantiate_it loop runs round instantiating the Id.
- -- It has to be a loop because we are now prepared to entertain
- -- types like
- -- f:: forall a. Eq a => forall b. Baz b => tau
- -- We want to instantiate this to
- -- f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
- instantiate_it orig fun ty
- = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) ->
- tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) ->
- instantiate_it2 orig fun tyvars theta tau
-
- instantiate_it2 orig fun tyvars theta tau
- = if null theta then -- Is it overloaded?
- returnNF_Tc (mkHsTyApp fun arg_tys, emptyLIE, tau)
- else
- -- Yes, it's overloaded
- instOverloadedFun orig fun arg_tys theta tau `thenNF_Tc` \ (fun', lie1) ->
- instantiate_it orig fun' tau `thenNF_Tc` \ (expr, lie2, final_tau) ->
- returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau)
-
- where
- arg_tys = mkTyVarTys tyvars
+\begin{code}
+tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, LIE, TcType)
+tcExpr_id (HsVar name) = tcId name
+tcExpr_id expr = newTyVarTy openTypeKind `thenNF_Tc` \ id_ty ->
+ tcMonoExpr expr id_ty `thenTc` \ (expr', lie_id) ->
+ returnTc (expr', lie_id, id_ty)
\end{code}
+
%************************************************************************
%* *
\subsection{@tcDoStmts@ typechecks a {\em list} of do statements}
ASSERT( not (null stmts) )
tcAddSrcLoc src_loc $
- newTyVarTy (mkArrowKind boxedTypeKind boxedTypeKind) `thenNF_Tc` \ m ->
- newTyVarTy boxedTypeKind `thenNF_Tc` \ elt_ty ->
- unifyTauTy res_ty (mkAppTy m elt_ty) `thenTc_`
-
-- If it's a comprehension we're dealing with,
-- force it to be a list comprehension.
-- (as of Haskell 98, monad comprehensions are no more.)
(case do_or_lc of
- ListComp -> unifyListTy res_ty `thenTc_` returnTc ()
- _ -> returnTc ()) `thenTc_`
+ ListComp -> unifyListTy res_ty `thenTc` \ elt_ty ->
+ returnNF_Tc (mkTyConTy listTyCon, (mkListTy, elt_ty))
+
+ _ -> newTyVarTy (mkArrowKind liftedTypeKind liftedTypeKind) `thenNF_Tc` \ m_ty ->
+ newTyVarTy liftedTypeKind `thenNF_Tc` \ elt_ty ->
+ unifyTauTy res_ty (mkAppTy m_ty elt_ty) `thenTc_`
+ returnNF_Tc (m_ty, (mkAppTy m_ty, elt_ty))
+ ) `thenNF_Tc` \ (tc_ty, m_ty) ->
- tcStmts do_or_lc (mkAppTy m) stmts elt_ty `thenTc` \ (stmts', stmts_lie) ->
+ tcStmts do_or_lc m_ty stmts `thenTc` \ (stmts', stmts_lie) ->
-- Build the then and zero methods in case we need them
-- It's important that "then" and "return" appear just once in the final LIE,
-- then = then
-- where the second "then" sees that it already exists in the "available" stuff.
--
- tcLookupValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id ->
- tcLookupValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id ->
- tcLookupValueByKey failMClassOpKey `thenNF_Tc` \ fail_sel_id ->
- newMethod DoOrigin return_sel_id [m] `thenNF_Tc` \ (return_lie, return_id) ->
- newMethod DoOrigin then_sel_id [m] `thenNF_Tc` \ (then_lie, then_id) ->
- newMethod DoOrigin fail_sel_id [m] `thenNF_Tc` \ (fail_lie, fail_id) ->
+ tcLookupGlobalId returnMName `thenNF_Tc` \ return_sel_id ->
+ tcLookupGlobalId thenMName `thenNF_Tc` \ then_sel_id ->
+ tcLookupGlobalId failMName `thenNF_Tc` \ fail_sel_id ->
+ newMethod DoOrigin return_sel_id [tc_ty] `thenNF_Tc` \ return_inst ->
+ newMethod DoOrigin then_sel_id [tc_ty] `thenNF_Tc` \ then_inst ->
+ newMethod DoOrigin fail_sel_id [tc_ty] `thenNF_Tc` \ fail_inst ->
let
- monad_lie = then_lie `plusLIE` return_lie `plusLIE` fail_lie
+ monad_lie = mkLIE [return_inst, then_inst, fail_inst]
in
- returnTc (HsDoOut do_or_lc stmts' return_id then_id fail_id res_ty src_loc,
+ returnTc (HsDoOut do_or_lc stmts'
+ (instToId return_inst) (instToId then_inst) (instToId fail_inst)
+ res_ty src_loc,
stmts_lie `plusLIE` monad_lie)
\end{code}
Game plan for record bindings
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-For each binding
- field = value
-1. look up "field", to find its selector Id, which must have type
- forall a1..an. T a1 .. an -> tau
- where tau is the type of the field.
+1. Find the TyCon for the bindings, from the first field label.
-2. Instantiate this type
+2. Instantiate its tyvars and unify (T a1 .. an) with expected_ty.
-3. Unify the (T a1 .. an) part with the "expected result type", which
- is passed in. This checks that all the field labels come from the
- same type.
+For each binding field = value
-4. Type check the value using tcArg, passing tau as the expected
- argument type.
+3. Instantiate the field type (from the field label) using the type
+ envt from step 2.
+
+4 Type check the value using tcArg, passing the field type as
+ the expected argument type.
This extends OK when the field types are universally quantified.
-Actually, to save excessive creation of fresh type variables,
-we
\begin{code}
tcRecordBinds
- :: TcType -- Expected type of whole record
+ :: TyCon -- Type constructor for the record
+ -> [TcType] -- Args of this type constructor
-> RenamedRecordBinds
- -> TcM s (TcRecordBinds, LIE)
+ -> TcM (TcRecordBinds, LIE)
-tcRecordBinds expected_record_ty rbinds
+tcRecordBinds tycon ty_args rbinds
= mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) ->
returnTc (rbinds', plusLIEs lies)
where
- do_bind (field_label, rhs, pun_flag)
- = tcLookupValue field_label `thenNF_Tc` \ sel_id ->
+ tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args
+
+ do_bind (field_lbl_name, rhs, pun_flag)
+ = tcLookupGlobalId field_lbl_name `thenNF_Tc` \ sel_id ->
+ let
+ field_lbl = recordSelectorFieldLabel sel_id
+ field_ty = substTy tenv (fieldLabelType field_lbl)
+ in
ASSERT( isRecordSelector sel_id )
-- This lookup and assertion will surely succeed, because
-- we check that the fields are indeed record selectors
-- before calling tcRecordBinds
+ ASSERT2( fieldLabelTyCon field_lbl == tycon, ppr field_lbl )
+ -- The caller of tcRecordBinds has already checked
+ -- that all the fields come from the same type
- tcInstId sel_id `thenNF_Tc` \ (_, _, tau) ->
+ tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) ->
- -- Record selectors all have type
- -- forall a1..an. T a1 .. an -> tau
- ASSERT( maybeToBool (splitFunTy_maybe tau) )
- let
- -- Selector must have type RecordType -> FieldType
- Just (record_ty, field_ty) = splitFunTy_maybe tau
- in
- unifyTauTy expected_record_ty record_ty `thenTc_`
- tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) ->
returnTc ((sel_id, rhs', pun_flag), lie)
badFields rbinds data_con
]
where
field_names = map fieldLabelName (dataConFieldLabels data_con)
+
+missingFields rbinds data_con
+ | null field_labels = ([], []) -- Not declared as a record;
+ -- But C{} is still valid
+ | otherwise
+ = (missing_strict_fields, other_missing_fields)
+ where
+ missing_strict_fields
+ = [ fl | (fl, str) <- field_info,
+ isMarkedStrict str,
+ not (fieldLabelName fl `elem` field_names_used)
+ ]
+ other_missing_fields
+ = [ fl | (fl, str) <- field_info,
+ not (isMarkedStrict str),
+ not (fieldLabelName fl `elem` field_names_used)
+ ]
+
+ field_names_used = [ field_name | (field_name, _, _) <- rbinds ]
+ field_labels = dataConFieldLabels data_con
+
+ field_info = zipEqual "missingFields"
+ field_labels
+ (drop (length ex_theta) (dataConStrictMarks data_con))
+ -- The 'drop' is because dataConStrictMarks
+ -- includes the existential dictionaries
+ (_, _, _, ex_theta, _, _) = dataConSig data_con
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM s ([TcExpr], LIE)
+tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM ([TcExpr], LIE)
tcMonoExprs [] [] = returnTc ([], emptyLIE)
tcMonoExprs (expr:exprs) (ty:tys)
\end{code}
-% =================================================
+%************************************************************************
+%* *
+\subsection{Literals}
+%* *
+%************************************************************************
-Errors and contexts
-~~~~~~~~~~~~~~~~~~~
+Overloaded literals.
-Mini-utils:
\begin{code}
-pp_nest_hang :: String -> SDoc -> SDoc
-pp_nest_hang label stuff = nest 2 (hang (text label) 4 stuff)
+tcLit :: HsLit -> TcType -> TcM (TcExpr, LIE)
+tcLit (HsLitLit s _) res_ty
+ = tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass ->
+ newDicts (LitLitOrigin (_UNPK_ s))
+ [mkClassPred cCallableClass [res_ty]] `thenNF_Tc` \ dicts ->
+ returnTc (HsLit (HsLitLit s res_ty), mkLIE dicts)
+
+tcLit lit res_ty
+ = unifyTauTy res_ty (simpleHsLitTy lit) `thenTc_`
+ returnTc (HsLit lit, emptyLIE)
\end{code}
+
+%************************************************************************
+%* *
+\subsection{Errors and contexts}
+%* *
+%************************************************************************
+
+Mini-utils:
+
Boring and alphabetical:
\begin{code}
arithSeqCtxt expr
lurkingRank2Err fun fun_ty
= hang (hsep [ptext SLIT("Illegal use of"), quotes (ppr fun)])
4 (vcat [ptext SLIT("It is applied to too few arguments"),
- ptext SLIT("so that the result type has for-alls in it")])
-
-rank2ArgCtxt arg expected_arg_ty
- = ptext SLIT("In a polymorphic function argument:") <+> ppr arg
+ ptext SLIT("so that the result type has for-alls in it:") <+> ppr fun_ty])
badFieldsUpd rbinds
= hang (ptext SLIT("No constructor has all these fields:"))
where
fields = [field | (field, _, _) <- rbinds]
-recordUpdCtxt = ptext SLIT("In a record update construct")
+recordUpdCtxt expr = ptext SLIT("In the record update:") <+> ppr expr
+recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr
notSelector field
= hsep [quotes (ppr field), ptext SLIT("is not a record selector")]
-illegalCcallTyErr isArg ty
- = hang (hsep [ptext SLIT("Unacceptable"), arg_or_res, ptext SLIT("type in _ccall_ or _casm_:")])
- 4 (hsep [ppr ty])
- where
- arg_or_res
- | isArg = ptext SLIT("argument")
- | otherwise = ptext SLIT("result")
-
+missingStrictFieldCon :: Name -> FieldLabel -> SDoc
+missingStrictFieldCon con field
+ = hsep [ptext SLIT("Constructor") <+> quotes (ppr con),
+ ptext SLIT("does not have the required strict field"), quotes (ppr field)]
+missingFieldCon :: Name -> FieldLabel -> SDoc
+missingFieldCon con field
+ = hsep [ptext SLIT("Field") <+> quotes (ppr field),
+ ptext SLIT("is not initialised")]
\end{code}
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