\section[TcExpr]{Typecheck an expression}
\begin{code}
-module TcExpr ( tcExpr, tcPolyExpr, tcId ) where
+module TcExpr ( tcApp, tcExpr, tcPolyExpr, tcId ) where
#include "HsVersions.h"
import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..),
- HsBinds(..), Stmt(..), StmtCtxt(..),
- failureFreePat
+ HsBinds(..), Stmt(..), StmtCtxt(..)
)
import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds )
import TcHsSyn ( TcExpr, TcRecordBinds,
- mkHsTyApp
+ mkHsTyApp, mkHsLet, maybeBoxedPrimType
)
import TcMonad
import Inst ( Inst, InstOrigin(..), OverloadedLit(..),
LIE, emptyLIE, unitLIE, plusLIE, plusLIEs, newOverloadedLit,
- newMethod, newMethodWithGivenTy, newDicts, instToId )
+ newMethod, instOverloadedFun, newDicts, instToId )
import TcBinds ( tcBindsAndThen )
-import TcEnv ( TcIdOcc(..), tcInstId, tidyType,
- tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey,
- tcLookupGlobalValueByKey,
- tcExtendGlobalTyVars, tcLookupGlobalValueMaybe,
+import TcEnv ( tcInstId,
+ tcLookupValue, tcLookupClassByKey,
+ tcLookupValueByKey,
+ tcExtendGlobalTyVars, tcLookupValueMaybe,
tcLookupTyCon, tcLookupDataCon
)
-import TcMatches ( tcMatchesCase, tcMatchExpected )
-import TcGRHSs ( tcStmts )
-import TcMonoType ( tcHsTcType, checkSigTyVars, sigCtxt )
+import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts )
+import TcMonoType ( tcHsType, checkSigTyVars, sigCtxt )
import TcPat ( badFieldCon )
import TcSimplify ( tcSimplifyAndCheck )
-import TcType ( TcType, TcTauType, TcMaybe(..),
+import TcType ( TcType, TcTauType,
tcInstTyVars,
tcInstTcType, tcSplitRhoTy,
- newTyVarTy, zonkTcType )
+ newTyVarTy, newTyVarTy_OpenKind, zonkTcType )
import Class ( Class )
import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType )
import DataCon ( dataConFieldLabels, dataConSig, dataConId )
import Name ( Name )
import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys,
- splitFunTy_maybe, splitFunTys,
+ splitFunTy_maybe, splitFunTys, isNotUsgTy,
mkTyConApp,
splitForAllTys, splitRhoTy,
isTauTy, tyVarsOfType, tyVarsOfTypes,
isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe,
- boxedTypeKind, openTypeKind, mkArrowKind,
- substFlexiTheta
+ boxedTypeKind, mkArrowKind,
+ tidyOpenType
)
-import VarEnv ( zipVarEnv )
+import Subst ( mkTopTyVarSubst, substTheta )
+import UsageSPUtils ( unannotTy )
import VarSet ( elemVarSet, mkVarSet )
import TyCon ( tyConDataCons )
import TysPrim ( intPrimTy, charPrimTy, doublePrimTy,
import Unique ( cCallableClassKey, cReturnableClassKey,
enumFromClassOpKey, enumFromThenClassOpKey,
enumFromToClassOpKey, enumFromThenToClassOpKey,
- thenMClassOpKey, zeroClassOpKey, returnMClassOpKey
+ thenMClassOpKey, failMClassOpKey, returnMClassOpKey
)
import Outputable
import Maybes ( maybeToBool )
%************************************************************************
\begin{code}
-tcExpr :: RenamedHsExpr -- Expession to type check
- -> TcType s -- Expected type (could be a polytpye)
- -> TcM s (TcExpr s, LIE s)
+tcExpr :: RenamedHsExpr -- Expession to type check
+ -> TcType -- Expected type (could be a polytpye)
+ -> TcM s (TcExpr, LIE)
tcExpr expr ty | isForAllTy ty = -- Polymorphic case
tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) ->
-- tcPolyExpr is like tcMonoExpr, except that the expected type
-- can be a polymorphic one.
tcPolyExpr :: RenamedHsExpr
- -> TcType s -- Expected type
- -> TcM s (TcExpr s, LIE s, -- Generalised expr with expected type, and LIE
- TcExpr s, TcTauType s, LIE s) -- Same thing, but instantiated; tau-type returned
+ -> TcType -- Expected type
+ -> TcM s (TcExpr, LIE, -- Generalised expr with expected type, and LIE
+ TcExpr, TcTauType, LIE) -- Same thing, but instantiated; tau-type returned
tcPolyExpr arg expected_arg_ty
= -- Ha! The argument type of the function is a for-all type,
(sig_theta, sig_tau) = splitRhoTy sig_rho
in
-- Type-check the arg and unify with expected type
- tcExtendGlobalTyVars (mkVarSet sig_tyvars) (
- tcMonoExpr arg sig_tau
- ) `thenTc` \ (arg', lie_arg) ->
+ tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) ->
- -- Check that the arg_tyvars havn't been constrained
+ -- Check that the sig_tyvars havn't been constrained
-- The interesting bit here is that we must include the free variables
-- of the expected arg ty. Here's an example:
-- runST (newVar True)
-- list of "free vars" for the signature check.
tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) $
- tcAddErrCtxtM (sigCtxt (text "an expression") sig_tau) $
+ tcAddErrCtxtM (sigCtxt sig_msg expected_arg_ty) $
checkSigTyVars sig_tyvars `thenTc` \ zonked_sig_tyvars ->
newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) ->
-- ToDo: better origin
tcSimplifyAndCheck
- (text "tcPolyExpr")
+ (text "the type signature of an expression")
(mkVarSet zonked_sig_tyvars)
sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) ->
-- a couple of new names which seems worse.
generalised_arg = TyLam zonked_sig_tyvars $
DictLam dict_ids $
- HsLet (MonoBind inst_binds [] Recursive)
+ mkHsLet inst_binds $
arg'
in
returnTc ( generalised_arg, free_insts,
arg', sig_tau, lie_arg )
+ where
+ sig_msg ty = sep [ptext SLIT("In an expression with expected type:"),
+ nest 4 (ppr ty)]
\end{code}
%************************************************************************
\begin{code}
tcMonoExpr :: RenamedHsExpr -- Expession to type check
- -> TcTauType s -- Expected type (could be a type variable)
- -> TcM s (TcExpr s, LIE s)
+ -> TcTauType -- Expected type (could be a type variable)
+ -> TcM s (TcExpr, LIE)
tcMonoExpr (HsVar name) res_ty
= tcId name `thenNF_Tc` \ (expr', lie, id_ty) ->
= tcMonoExpr (HsApp neg expr) res_ty
tcMonoExpr (HsLam match) res_ty
- = tcMatchExpected match res_ty LambdaBody `thenTc` \ (match',lie) ->
+ = tcMatchLambda match res_ty `thenTc` \ (match',lie) ->
returnTc (HsLam match', lie)
tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2]
= -- Get the callable and returnable classes.
tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass ->
- tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) ->
+ tcLookupTyCon ioTyCon_NAME `thenNF_Tc` \ ioTyCon ->
let
new_arg_dict (arg, arg_ty)
= newDicts (CCallOrigin (_UNPK_ lbl) (Just arg))
in
-- Arguments
- mapNF_Tc (\ _ -> newTyVarTy openTypeKind)
- [1..(length args)] `thenNF_Tc` \ ty_vars ->
- tcMonoExprs args ty_vars `thenTc` \ (args', args_lie) ->
+ let n_args = length args
+ tv_idxs | n_args == 0 = []
+ | otherwise = [1..n_args]
+ in
+ mapNF_Tc (\ _ -> newTyVarTy_OpenKind) tv_idxs `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
-- Construct the extra insts, which encode the
-- constraints on the argument and result types.
- mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args ty_vars) `thenNF_Tc` \ ccarg_dicts_s ->
- newDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) ->
-
- returnTc (HsApp (HsVar (RealId (dataConId ioDataCon)) `TyApp` [result_ty])
+ 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)
\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
-- case (map f) of
-- (x:xs) -> ...
-- will report that map is applied to too few arguments
+ --
+ -- Not only that, but it's better to check the matches on their
+ -- own, so that we get the expected results for scoped type variables.
+ -- f x = case x of
+ -- (p::a, q::b) -> (q,p)
+ -- The above should work: the match (p,q) -> (q,p) is polymorphic as
+ -- claimed by the pattern signatures. But if we typechecked the
+ -- match with x in scope and x's type as the expected type, we'd be hosed.
- tcMatchesCase res_ty matches `thenTc` \ (scrut_ty, matches', lie2) ->
+ tcMatchesCase matches res_ty `thenTc` \ (scrut_ty, matches', lie2) ->
tcAddErrCtxt (caseScrutCtxt scrut) (
tcMonoExpr scrut scrut_ty
let
bad_fields = badFields rbinds data_con
in
- mapNF_Tc (addErrTc . badFieldCon con_name) bad_fields `thenNF_Tc_`
+ if not (null bad_fields) then
+ mapNF_Tc (addErrTc . badFieldCon con_name) bad_fields `thenNF_Tc_`
+ failTc -- Fail now, because tcRecordBinds will crash on a bad field
+ else
-- Typecheck the record bindings
- -- (Do this after checkRecordFields in case there's a field that
- -- doesn't match the constructor.)
tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
returnTc (RecordConOut data_con con_expr rbinds', con_lie `plusLIE` rbinds_lie)
tcMonoExpr (RecordUpd record_expr rbinds) res_ty
= tcAddErrCtxt recordUpdCtxt $
- -- STEP 1
- -- Figure out the tycon and data cons from the first field name
+ -- STEP 0
+ -- Check that the field names are really field names
ASSERT( not (null rbinds) )
let
- ((first_field_name, _, _) : rest) = rbinds
+ field_names = [field_name | (field_name, _, _) <- rbinds]
in
- tcLookupGlobalValueMaybe first_field_name `thenNF_Tc` \ maybe_sel_id ->
- (case maybe_sel_id of
- Just sel_id | isRecordSelector sel_id -> returnTc sel_id
- other -> failWithTc (notSelector first_field_name)
- ) `thenTc` \ sel_id ->
+ mapNF_Tc tcLookupValueMaybe 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)
+ ]
+ in
+ mapNF_Tc (addErrTc . notSelector) bad_guys `thenTc_`
+ if not (null bad_guys) then
+ failTc
+ else
+
+ -- STEP 1
+ -- Figure out the tycon and data cons from the first field name
let
- (_, tau) = splitForAllTys (idType sel_id)
+ (Just sel_id : _) = maybe_sel_ids
+ (_, tau) = ASSERT( isNotUsgTy (idType sel_id) )
+ splitForAllTys (idType sel_id)
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)
tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) ->
-- STEP 2
- -- Check for bad fields
+ -- Check that at least one constructor has all the named fields
+ -- i.e. has an empty set of bad fields returned by badFields
checkTc (any (null . badFields rbinds) data_cons)
(badFieldsUpd rbinds) `thenTc_`
+
-- STEP 3
-- Typecheck the update bindings.
-- (Do this after checking for bad fields in case there's a field that
-- WARNING: this code assumes that all data_cons in a common tycon
-- have FieldLabels abstracted over the same tyvars.
let
- upd_field_lbls = [recordSelectorFieldLabel sel_id | (RealId sel_id, _, _) <- rbinds']
+ upd_field_lbls = [recordSelectorFieldLabel sel_id | (sel_id, _, _) <- rbinds']
con_field_lbls_s = map dataConFieldLabels data_cons
-- A constructor is only relevant to this process if
-- union the ones that could participate in the update.
let
(tyvars, theta, _, _, _, _) = dataConSig (head data_cons)
- inst_env = zipVarEnv tyvars result_inst_tys
- theta' = substFlexiTheta inst_env theta
+ inst_env = mkTopTyVarSubst tyvars result_inst_tys
+ theta' = substTheta inst_env theta
in
newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) ->
con_lie `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) ->
+ = unifyListTy res_ty `thenTc` \ elt_ty ->
+ tcMonoExpr expr elt_ty `thenTc` \ (expr', lie1) ->
- tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id ->
+ tcLookupValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id ->
newMethod (ArithSeqOrigin seq)
- (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) ->
+ sel_id [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) ->
returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'),
lie1 `plusLIE` lie2)
unifyListTy res_ty `thenTc` \ elt_ty ->
tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
- tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id ->
+ tcLookupValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id ->
newMethod (ArithSeqOrigin seq)
- (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) ->
+ sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_then_id) ->
returnTc (ArithSeqOut (HsVar enum_from_then_id)
(FromThen expr1' expr2'),
unifyListTy res_ty `thenTc` \ elt_ty ->
tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
- tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id ->
+ tcLookupValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id ->
newMethod (ArithSeqOrigin seq)
- (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) ->
+ sel_id [elt_ty] `thenNF_Tc` \ (lie3, enum_from_to_id) ->
returnTc (ArithSeqOut (HsVar enum_from_to_id)
(FromTo expr1' expr2'),
tcMonoExpr expr1 elt_ty `thenTc` \ (expr1',lie1) ->
tcMonoExpr expr2 elt_ty `thenTc` \ (expr2',lie2) ->
tcMonoExpr expr3 elt_ty `thenTc` \ (expr3',lie3) ->
- tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id ->
+ tcLookupValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id ->
newMethod (ArithSeqOrigin seq)
- (RealId sel_id) [elt_ty] `thenNF_Tc` \ (lie4, eft_id) ->
+ sel_id [elt_ty] `thenNF_Tc` \ (lie4, eft_id) ->
returnTc (ArithSeqOut (HsVar eft_id)
(FromThenTo expr1' expr2' expr3'),
\begin{code}
tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty
= tcSetErrCtxt (exprSigCtxt in_expr) $
- tcHsTcType poly_ty `thenTc` \ sig_tc_ty ->
+ tcHsType poly_ty `thenTc` \ sig_tc_ty ->
if not (isForAllTy sig_tc_ty) then
-- Easy case
\begin{code}
tcExpr_id :: RenamedHsExpr
- -> TcM s (TcExpr s,
- LIE s,
- TcType s)
+ -> TcM s (TcExpr,
+ LIE,
+ TcType)
tcExpr_id id_expr
= case id_expr of
- HsVar name -> tcId name `thenNF_Tc` \ stuff ->
+ HsVar name -> tcId name `thenNF_Tc` \ stuff ->
returnTc stuff
- other -> newTyVarTy openTypeKind `thenNF_Tc` \ id_ty ->
- tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) ->
+ other -> newTyVarTy_OpenKind `thenNF_Tc` \ id_ty ->
+ tcMonoExpr id_expr id_ty `thenTc` \ (id_expr', lie_id) ->
returnTc (id_expr', lie_id, id_ty)
\end{code}
\begin{code}
-tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
- -> TcType s -- Expected result type of application
- -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args
- LIE s)
+tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
+ -> TcType -- Expected result type of application
+ -> TcM s (TcExpr, [TcExpr], -- Translated fun and args
+ LIE)
tcApp fun args res_ty
= -- First type-check the function
= zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' ->
zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' ->
let
- (env1, exp_ty'') = tidyType tidy_env exp_ty'
- (env2, act_ty'') = tidyType env1 act_ty'
+ (env1, exp_ty'') = tidyOpenType tidy_env exp_ty'
+ (env2, act_ty'') = tidyOpenType env1 act_ty'
(exp_args, _) = splitFunTys exp_ty''
(act_args, _) = splitFunTys act_ty''
returnNF_Tc (env2, message)
-split_fun_ty :: TcType s -- The type of the function
+split_fun_ty :: TcType -- The type of the function
-> Int -- Number of arguments
- -> TcM s ([TcType s], -- Function argument types
- TcType s) -- Function result types
+ -> TcM s ([TcType], -- Function argument types
+ TcType) -- Function result types
split_fun_ty fun_ty 0
= returnTc ([], fun_ty)
\begin{code}
tcArg :: RenamedHsExpr -- The function (for error messages)
- -> (RenamedHsExpr, TcType s, Int) -- Actual argument and expected arg type
- -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE
+ -> (RenamedHsExpr, TcType, Int) -- Actual argument and expected arg type
+ -> TcM s (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 s, LIE s, TcType s)
+tcId :: Name -> NF_TcM s (TcExpr, LIE, TcType)
tcId name
= -- Look up the Id and instantiate its type
- tcLookupLocalValue name `thenNF_Tc` \ maybe_local ->
+ tcLookupValueMaybe name `thenNF_Tc` \ maybe_local ->
case maybe_local of
- Just tc_id -> instantiate_it (TcId tc_id) (idType tc_id)
+ Just tc_id -> instantiate_it (OccurrenceOf tc_id) (HsVar tc_id) (unannotTy (idType tc_id))
- Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id ->
+ Nothing -> tcLookupValue name `thenNF_Tc` \ id ->
tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) ->
- instantiate_it2 (RealId id) tyvars theta tau
+ instantiate_it2 (OccurrenceOf id) (HsVar id) tyvars theta tau
where
-- The instantiate_it loop runs round instantiating the Id.
-- 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 tc_id_occ ty
+ instantiate_it orig fun ty
= tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) ->
tcSplitRhoTy rho `thenNF_Tc` \ (theta, tau) ->
- instantiate_it2 tc_id_occ tyvars theta tau
+ instantiate_it2 orig fun tyvars theta tau
- instantiate_it2 tc_id_occ tyvars theta tau
+ instantiate_it2 orig fun tyvars theta tau
= if null theta then -- Is it overloaded?
- returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau)
+ returnNF_Tc (mkHsTyApp fun arg_tys, emptyLIE, tau)
else
-- Yes, it's overloaded
- newMethodWithGivenTy (OccurrenceOf tc_id_occ)
- tc_id_occ arg_tys theta tau `thenNF_Tc` \ inst ->
- instantiate_it (instToId inst) tau `thenNF_Tc` \ (expr, lie2, final_tau) ->
- returnNF_Tc (expr, unitLIE inst `plusLIE` lie2, final_tau)
+ 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
+ arg_tys = mkTyVarTys tyvars
\end{code}
%************************************************************************
newTyVarTy boxedTypeKind `thenNF_Tc` \ elt_ty ->
unifyTauTy res_ty (mkAppTy m elt_ty) `thenTc_`
- tcStmts do_or_lc (mkAppTy m) stmts elt_ty `thenTc` \ (stmts', stmts_lie) ->
+ -- 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_`
+
+ tcStmts do_or_lc (mkAppTy m) stmts elt_ty `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.
--
- tcLookupGlobalValueByKey returnMClassOpKey `thenNF_Tc` \ return_sel_id ->
- tcLookupGlobalValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id ->
- tcLookupGlobalValueByKey zeroClassOpKey `thenNF_Tc` \ zero_sel_id ->
- newMethod DoOrigin
- (RealId return_sel_id) [m] `thenNF_Tc` \ (return_lie, return_id) ->
- newMethod DoOrigin
- (RealId then_sel_id) [m] `thenNF_Tc` \ (then_lie, then_id) ->
- newMethod DoOrigin
- (RealId zero_sel_id) [m] `thenNF_Tc` \ (zero_lie, zero_id) ->
+ 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) ->
let
- monad_lie = then_lie `plusLIE` return_lie `plusLIE` perhaps_zero_lie
- perhaps_zero_lie | all failure_free stmts' = emptyLIE
- | otherwise = zero_lie
-
- failure_free (BindStmt pat _ _) = failureFreePat pat
- failure_free (GuardStmt _ _) = False
- failure_free other_stmt = True
+ monad_lie = then_lie `plusLIE` return_lie `plusLIE` fail_lie
in
- returnTc (HsDoOut do_or_lc stmts' return_id then_id zero_id res_ty src_loc,
+ returnTc (HsDoOut do_or_lc stmts' return_id then_id fail_id res_ty src_loc,
stmts_lie `plusLIE` monad_lie)
\end{code}
\begin{code}
tcRecordBinds
- :: TcType s -- Expected type of whole record
+ :: TcType -- Expected type of whole record
-> RenamedRecordBinds
- -> TcM s (TcRecordBinds s, LIE s)
+ -> TcM s (TcRecordBinds, LIE)
tcRecordBinds expected_record_ty rbinds
= mapAndUnzipTc do_bind rbinds `thenTc` \ (rbinds', lies) ->
returnTc (rbinds', plusLIEs lies)
where
do_bind (field_label, rhs, pun_flag)
- = tcLookupGlobalValue field_label `thenNF_Tc` \ sel_id ->
+ = tcLookupValue field_label `thenNF_Tc` \ sel_id ->
ASSERT( isRecordSelector sel_id )
-- This lookup and assertion will surely succeed, because
-- we check that the fields are indeed record selectors
in
unifyTauTy expected_record_ty record_ty `thenTc_`
tcPolyExpr rhs field_ty `thenTc` \ (rhs', lie, _, _, _) ->
- returnTc ((RealId sel_id, rhs', pun_flag), lie)
+ returnTc ((sel_id, rhs', pun_flag), lie)
badFields rbinds data_con
= [field_name | (field_name, _, _) <- rbinds,
%************************************************************************
\begin{code}
-tcMonoExprs :: [RenamedHsExpr] -> [TcType s] -> TcM s ([TcExpr s], LIE s)
+tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM s ([TcExpr], LIE)
tcMonoExprs [] [] = returnTc ([], emptyLIE)
tcMonoExprs (expr:exprs) (ty:tys)
Mini-utils:
\begin{code}
pp_nest_hang :: String -> SDoc -> SDoc
-pp_nest_hang label stuff = nest 2 (hang (text label) 4 stuff)
+pp_nest_hang lbl stuff = nest 2 (hang (text lbl) 4 stuff)
\end{code}
Boring and alphabetical:
the_app = foldl HsApp fun args -- Used in error messages
appCtxt fun args
- = ptext SLIT("In the application") <+> (ppr the_app)
+ = ptext SLIT("In the application") <+> quotes (ppr the_app)
where
the_app = foldl HsApp fun args -- Used in error messages
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")
+
+
\end{code}
projects / ghc-hetmet.git / blobdiff