%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[TcExpr]{TcExpr}
+\section[TcExpr]{Typecheck an expression}
\begin{code}
+module TcExpr ( tcApp, tcExpr, tcPolyExpr, tcId ) where
+
#include "HsVersions.h"
-module TcExpr (
- tcExpr
-#ifdef DPH
- , tcExprs
-#endif
- ) where
-
-import TcMonad -- typechecking monad machinery
-import TcMonadFns ( newPolyTyVarTy, newOpenTyVarTy,
- newDict, newMethod, newOverloadedLit,
- applyTcSubstAndCollectTyVars,
- mkIdsWithPolyTyVarTys
+import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..),
+ HsBinds(..), MonoBinds(..), Stmt(..), StmtCtxt(..),
+ mkMonoBind, nullMonoBinds
+ )
+import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds )
+import TcHsSyn ( TcExpr, TcRecordBinds, mkHsConApp,
+ mkHsTyApp, mkHsLet
)
-import AbsSyn -- the stuff being typechecked
+import TcMonad
+import BasicTypes ( RecFlag(..) )
-import AbsPrel ( intPrimTy, charPrimTy, doublePrimTy,
- floatPrimTy, addrPrimTy, addrTy,
- boolTy, charTy, stringTy, mkFunTy, mkListTy,
- mkTupleTy, mkPrimIoTy
-#ifdef DPH
- ,mkProcessorTy, mkPodTy,toPodId,
- processorClass,pidClass
-#endif {- Data Parallel Haskell -}
+import Inst ( Inst, InstOrigin(..), OverloadedLit(..),
+ LIE, emptyLIE, unitLIE, consLIE, plusLIE, plusLIEs,
+ lieToList, listToLIE,
+ newOverloadedLit, newMethod, newIPDict,
+ instOverloadedFun, newDicts, newClassDicts,
+ getIPsOfLIE, instToId, ipToId
+ )
+import TcBinds ( tcBindsAndThen )
+import TcEnv ( tcInstId,
+ tcLookupValue, tcLookupClassByKey,
+ tcLookupValueByKey,
+ tcExtendGlobalTyVars, tcLookupValueMaybe,
+ tcLookupTyCon, tcLookupDataCon
+ )
+import TcMatches ( tcMatchesCase, tcMatchLambda, tcStmts )
+import TcMonoType ( tcHsSigType, checkSigTyVars, sigCtxt )
+import TcPat ( badFieldCon )
+import TcSimplify ( tcSimplify, tcSimplifyAndCheck, partitionPredsOfLIE )
+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, mkVanillaId
+ )
+import DataCon ( dataConFieldLabels, dataConSig,
+ dataConStrictMarks, StrictnessMark(..)
+ )
+import Name ( Name, getName )
+import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys,
+ ipName_maybe,
+ splitFunTy_maybe, splitFunTys, isNotUsgTy,
+ mkTyConApp,
+ splitForAllTys, splitRhoTy,
+ isTauTy, tyVarsOfType, tyVarsOfTypes,
+ isForAllTy, splitAlgTyConApp, splitAlgTyConApp_maybe,
+ boxedTypeKind, mkArrowKind,
+ tidyOpenType
)
-import AbsUniType
-import E
-import CE ( lookupCE )
-
-import Errors
-import GenSpecEtc ( checkSigTyVars )
-import Id ( mkInstId, getIdUniType, Id )
-import Inst
-import LIE ( nullLIE, unitLIE, plusLIE, unMkLIE, mkLIE, LIE )
-import ListSetOps ( unionLists )
-import Maybes ( Maybe(..) )
-import TVE ( nullTVE, TVE(..) )
-import Spec ( specId, specTy )
-import TcBinds ( tcLocalBindsAndThen )
-import TcMatches ( tcMatchesCase, tcMatch )
-import TcPolyType ( tcPolyType )
-import TcQuals ( tcQuals )
-import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 )
-#ifdef DPH
-import TcParQuals
-#endif {- Data Parallel Haskell -}
-import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists )
-import UniqFM ( emptyUFM ) -- profiling, pragmas only
-import Unique -- *Key stuff
+import Subst ( mkTopTyVarSubst, substClasses )
+import UsageSPUtils ( unannotTy )
+import VarSet ( emptyVarSet, unionVarSet, 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 Outputable
+import Maybes ( maybeToBool, mapMaybe )
+import ListSetOps ( minusList )
import Util
+import CmdLineOpts ( opt_WarnMissingFields )
-tcExpr :: E -> RenamedExpr -> TcM (TypecheckedExpr, LIE, UniType)
\end{code}
%************************************************************************
%* *
-\subsection{The TAUT rules for variables}
+\subsection{Main wrappers}
%* *
%************************************************************************
\begin{code}
-tcExpr e (Var name)
- = specId (lookupE_Value e name) `thenNF_Tc` \ stuff@(expr, lie, ty) ->
+tcExpr :: RenamedHsExpr -- Expession to type check
+ -> TcType -- Expected type (could be a polytpye)
+ -> TcM s (TcExpr, LIE)
- -- Check that there's no lurking rank-2 polymorphism
- -- isTauTy is over-paranoid, because we don't expect
- -- any submerged polymorphism other than rank-2 polymorphism
+tcExpr expr ty | isForAllTy ty = -- Polymorphic case
+ tcPolyExpr expr ty `thenTc` \ (expr', lie, _, _, _) ->
+ returnTc (expr', lie)
- getSrcLocTc `thenNF_Tc` \ loc ->
- checkTc (not (isTauTy ty)) (lurkingRank2Err name ty loc) `thenTc_`
-
- returnTc stuff
+ | otherwise = -- Monomorphic case
+ tcMonoExpr expr ty
\end{code}
+
%************************************************************************
%* *
-\subsection{Literals}
+\subsection{@tcPolyExpr@ typchecks an application}
%* *
%************************************************************************
-Overloaded literals.
-
\begin{code}
-tcExpr e (Lit lit@(IntLit i))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- newPolyTyVarTy `thenNF_Tc` \ ty ->
+-- tcPolyExpr is like tcMonoExpr, except that the expected type
+-- can be a polymorphic one.
+tcPolyExpr :: RenamedHsExpr
+ -> 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,
+ -- An example of rank-2 polymorphism.
+
+ -- 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) ->
let
- from_int = lookupE_ClassOpByKey e numClassKey SLIT("fromInt")
- from_integer = lookupE_ClassOpByKey e numClassKey SLIT("fromInteger")
+ (sig_theta, sig_tau) = splitRhoTy sig_rho
+ free_tyvars = tyVarsOfType expected_arg_ty
in
- newOverloadedLit (LiteralOrigin lit loc)
- (OverloadedIntegral i from_int from_integer)
- ty
- `thenNF_Tc` \ over_lit ->
+ -- Type-check the arg and unify with expected type
+ tcMonoExpr arg sig_tau `thenTc` \ (arg', lie_arg) ->
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
+ -- 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)
+ -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool))
+ -- for (newVar True), with s fresh. Then we unify with the runST's arg type
+ -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool.
+ -- So now s' isn't unconstrained because it's linked to a.
+ -- Conclusion: include the free vars of the expected arg type in the
+ -- list of "free vars" for the signature check.
-tcExpr e (Lit lit@(FracLit f))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- newPolyTyVarTy `thenNF_Tc` \ ty ->
- let
- from_rational = lookupE_ClassOpByKey e fractionalClassKey SLIT("fromRational")
- in
- newOverloadedLit (LiteralOrigin lit loc)
- (OverloadedFractional f from_rational)
- ty
- `thenNF_Tc` \ over_lit ->
+ tcExtendGlobalTyVars free_tyvars $
+ tcAddErrCtxtM (sigCtxt sig_msg sig_tyvars sig_theta sig_tau) $
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
+ checkSigTyVars sig_tyvars free_tyvars `thenTc` \ zonked_sig_tyvars ->
+
+ newDicts SignatureOrigin sig_theta `thenNF_Tc` \ (sig_dicts, dict_ids) ->
+ -- ToDo: better origin
+ tcSimplifyAndCheck
+ (text "the type signature of an expression")
+ (mkVarSet zonked_sig_tyvars)
+ sig_dicts lie_arg `thenTc` \ (free_insts, inst_binds) ->
-tcExpr e (Lit lit@(LitLitLitIn s))
- = getSrcLocTc `thenNF_Tc` \ loc ->
let
- -- Get the callable class. Rather turgid and a HACK (ToDo).
- ce = getE_CE e
- cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom)
- bottom = panic "tcExpr:LitLitLit"
+ -- 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 $
+ mkHsLet inst_binds $
+ arg'
in
- newPolyTyVarTy `thenNF_Tc` \ ty ->
-
- newDict (LitLitOrigin loc (_UNPK_ s)) cCallableClass ty `thenNF_Tc` \ dict ->
+ returnTc ( generalised_arg, free_insts,
+ arg', sig_tau, lie_arg )
+ where
+ sig_msg = ptext SLIT("When checking an expression type signature")
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{The TAUT rules for variables}
+%* *
+%************************************************************************
+
+\begin{code}
+tcMonoExpr :: RenamedHsExpr -- Expession to type check
+ -> 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) ->
+ unifyTauTy res_ty id_ty `thenTc_`
+
+ -- 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 id_ty)
+ (lurkingRank2Err name id_ty) `thenTc_`
+
+ returnTc (expr', lie)
+\end{code}
+
+\begin{code}
+tcMonoExpr (HsIPVar name) res_ty
+ -- ZZ What's the `id' used for here...
+ = let id = mkVanillaId name res_ty in
+ tcGetInstLoc (OccurrenceOf id) `thenNF_Tc` \ loc ->
+ newIPDict name res_ty loc `thenNF_Tc` \ ip ->
+ returnNF_Tc (HsIPVar (instToId ip), unitLIE ip)
+\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
+
- returnTc (Lit (LitLitLit s ty), mkLIE [dict], ty)
+tcMonoExpr (HsLit lit@(HsLitLit s)) res_ty
+ = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
+ newClassDicts (LitLitOrigin (_UNPK_ s))
+ [(cCallableClass,[res_ty])] `thenNF_Tc` \ (dicts, _) ->
+ returnTc (HsLitOut lit res_ty, dicts)
\end{code}
Primitive literals:
\begin{code}
-tcExpr e (Lit (CharPrimLit c))
- = returnTc (Lit (CharPrimLit c), nullLIE, charPrimTy)
+tcMonoExpr (HsLit lit@(HsCharPrim c)) res_ty
+ = unifyTauTy res_ty charPrimTy `thenTc_`
+ returnTc (HsLitOut lit charPrimTy, emptyLIE)
-tcExpr e (Lit (StringPrimLit s))
- = returnTc (Lit (StringPrimLit s), nullLIE, addrPrimTy)
+tcMonoExpr (HsLit lit@(HsStringPrim s)) res_ty
+ = unifyTauTy res_ty addrPrimTy `thenTc_`
+ returnTc (HsLitOut lit addrPrimTy, emptyLIE)
-tcExpr e (Lit (IntPrimLit i))
- = returnTc (Lit (IntPrimLit i), nullLIE, intPrimTy)
+tcMonoExpr (HsLit lit@(HsIntPrim i)) res_ty
+ = unifyTauTy res_ty intPrimTy `thenTc_`
+ returnTc (HsLitOut lit intPrimTy, emptyLIE)
-tcExpr e (Lit (FloatPrimLit f))
- = returnTc (Lit (FloatPrimLit f), nullLIE, floatPrimTy)
+tcMonoExpr (HsLit lit@(HsFloatPrim f)) res_ty
+ = unifyTauTy res_ty floatPrimTy `thenTc_`
+ returnTc (HsLitOut lit floatPrimTy, emptyLIE)
-tcExpr e (Lit (DoublePrimLit d))
- = returnTc (Lit (DoublePrimLit d), nullLIE, doublePrimTy)
+tcMonoExpr (HsLit lit@(HsDoublePrim d)) res_ty
+ = unifyTauTy res_ty doublePrimTy `thenTc_`
+ returnTc (HsLitOut lit doublePrimTy, emptyLIE)
\end{code}
Unoverloaded literals:
\begin{code}
-tcExpr e (Lit (CharLit c))
- = returnTc (Lit (CharLit c), nullLIE, charTy)
+tcMonoExpr (HsLit lit@(HsChar c)) res_ty
+ = unifyTauTy res_ty charTy `thenTc_`
+ returnTc (HsLitOut lit charTy, emptyLIE)
-tcExpr e (Lit (StringLit str))
- = returnTc (Lit (StringLit str), nullLIE, stringTy)
+tcMonoExpr (HsLit lit@(HsString str)) res_ty
+ = unifyTauTy res_ty stringTy `thenTc_`
+ returnTc (HsLitOut lit stringTy, emptyLIE)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcExpr e (Lam match)
- = tcMatch e match `thenTc` \ (match',lie,ty) ->
- returnTc (Lam match',lie,ty)
+tcMonoExpr (HsPar expr) res_ty -- preserve parens so printing needn't guess where they go
+ = tcMonoExpr expr res_ty
-tcExpr e (App e1 e2) = accum e1 [e2]
- where
- accum (App e1 e2) args = accum e1 (e2:args)
- accum fun args = tcApp (foldl App) e fun args
+-- 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 (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 (HsLam match) res_ty
+ = tcMatchLambda match res_ty `thenTc` \ (match',lie) ->
+ returnTc (HsLam match', lie)
+
+tcMonoExpr (HsApp e1 e2) res_ty = accum e1 [e2]
+ where
+ accum (HsApp e1 e2) args = accum e1 (e2:args)
+ accum fun args
+ = tcApp fun args res_ty `thenTc` \ (fun', args', lie) ->
+ returnTc (foldl HsApp fun' args', lie)
-- equivalent to (op e1) e2:
-tcExpr e (OpApp e1 op e2)
- = tcApp (\fun [arg1,arg2] -> OpApp arg1 fun arg2) e op [e1,e2]
+tcMonoExpr (OpApp arg1 op fix arg2) res_ty
+ = tcApp op [arg1,arg2] res_ty `thenTc` \ (op', [arg1', arg2'], lie) ->
+ returnTc (OpApp arg1' op' fix arg2', lie)
\end{code}
Note that the operators in sections are expected to be binary, and
a type error will occur if they aren't.
\begin{code}
--- equivalent to
--- \ x -> e op x,
+-- Left sections, equivalent to
+-- \ x -> e op x,
-- or
--- \ x -> op e x,
+-- \ x -> op e x,
-- or just
-- op e
-tcExpr e (SectionL expr op)
- = tcApp (\ fun [arg] -> SectionL arg fun) e op [expr]
+tcMonoExpr in_expr@(SectionL arg op) res_ty
+ = tcApp op [arg] res_ty `thenTc` \ (op', [arg'], lie) ->
--- equivalent to \ x -> x op expr, or
--- \ x -> op x expr
+ -- Check that res_ty is a function type
+ -- Without this check we barf in the desugarer on
+ -- f op = (3 `op`)
+ -- because it tries to desugar to
+ -- f op = \r -> 3 op r
+ -- so (3 `op`) had better be a function!
+ tcAddErrCtxt (sectionLAppCtxt in_expr) $
+ unifyFunTy res_ty `thenTc_`
-tcExpr e (SectionR op expr)
- = tcExpr e op `thenTc` \ (op', lie1, op_ty) ->
- tcExpr e expr `thenTc` \ (expr',lie2, expr_ty) ->
- newOpenTyVarTy `thenNF_Tc` \ ty1 ->
- newOpenTyVarTy `thenNF_Tc` \ ty2 ->
- let
- result_ty = mkFunTy ty1 ty2
- in
- unifyTauTy op_ty (mkFunTy ty1 (mkFunTy expr_ty ty2))
- (SectionRAppCtxt op expr) `thenTc_`
+ returnTc (SectionL arg' op', lie)
+
+-- Right sections, equivalent to \ x -> x op expr, or
+-- \ x -> op x expr
- returnTc (SectionR op' expr', plusLIE lie1 lie2, result_ty)
+tcMonoExpr in_expr@(SectionR op expr) res_ty
+ = tcExpr_id op `thenTc` \ (op', lie1, op_ty) ->
+ tcAddErrCtxt (sectionRAppCtxt in_expr) $
+ split_fun_ty op_ty 2 {- two args -} `thenTc` \ ([arg1_ty, arg2_ty], op_res_ty) ->
+ tcMonoExpr expr arg2_ty `thenTc` \ (expr',lie2) ->
+ unifyTauTy res_ty (mkFunTy arg1_ty op_res_ty) `thenTc_`
+ returnTc (SectionR op' expr', lie1 `plusLIE` lie2)
\end{code}
The interesting thing about @ccall@ is that it is just a template
later use.
\begin{code}
-tcExpr e (CCall lbl args may_gc is_asm ignored_fake_result_ty)
- = getSrcLocTc `thenNF_Tc` \ src_loc ->
+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 ->
let
- -- Get the callable and returnable classes. Rather turgid (ToDo).
- ce = getE_CE e
- cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom)
- cReturnableClass = lookupCE ce (PreludeClass cReturnableClassKey bottom)
- bottom = panic "tcExpr:CCall"
+ new_arg_dict (arg, arg_ty)
+ = newClassDicts (CCallOrigin (_UNPK_ lbl) (Just arg))
+ [(cCallableClass, [arg_ty])] `thenNF_Tc` \ (arg_dicts, _) ->
+ returnNF_Tc arg_dicts -- Actually a singleton bag
- new_arg_dict (arg, arg_ty) = newDict (CCallOrigin src_loc (_UNPK_ lbl) (Just arg))
- cCallableClass arg_ty
-
- result_origin = CCallOrigin src_loc (_UNPK_ lbl) Nothing {- Not an arg -}
+ result_origin = CCallOrigin (_UNPK_ lbl) Nothing {- Not an arg -}
in
-
+
-- Arguments
- tcExprs e args `thenTc` \ (args', args_lie, arg_tys) ->
+ 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 PrimIO
+ -- type must, however, be boxed since it's an argument to the IO
-- type constructor.
- newPolyTyVarTy `thenNF_Tc` \ result_ty ->
+ newTyVarTy boxedTypeKind `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 (args `zip` arg_tys) `thenNF_Tc` \ arg_dicts ->
- newDict result_origin cReturnableClass result_ty `thenNF_Tc` \ res_dict ->
-
- returnTc (CCall lbl args' may_gc is_asm result_ty,
- args_lie `plusLIE` mkLIE (res_dict : arg_dicts),
- mkPrimIoTy result_ty)
+ mapNF_Tc new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s ->
+ newClassDicts result_origin [(cReturnableClass, [result_ty])] `thenNF_Tc` \ (ccres_dict, _) ->
+ returnTc (HsCCall lbl args' may_gc is_asm io_result_ty,
+ foldr plusLIE ccres_dict ccarg_dicts_s `plusLIE` args_lie)
\end{code}
\begin{code}
-tcExpr e (SCC label expr)
- = tcExpr e expr `thenTc` \ (expr', lie, expr_ty) ->
- -- No unification. Give SCC the type of expr
- returnTc (SCC label expr', lie, expr_ty)
-
-tcExpr e (Let binds expr)
- = tcLocalBindsAndThen e
- Let -- The combiner
- binds -- Bindings to check
- (\ e -> tcExpr e expr) -- Typechecker for the expression
-
-tcExpr e (Case expr matches)
- = tcExpr e expr `thenTc` \ (expr',lie1,expr_ty) ->
- tcMatchesCase e matches `thenTc` \ (matches',lie2,match_ty) ->
- newOpenTyVarTy `thenNF_Tc` \ result_ty ->
-
- unifyTauTy (mkFunTy expr_ty result_ty) match_ty
- (CaseCtxt expr matches) `thenTc_`
-
- returnTc (Case expr' matches', plusLIE lie1 lie2, result_ty)
-
-tcExpr e (If pred b1 b2)
- = tcExpr e pred `thenTc` \ (pred',lie1,predTy) ->
-
- unifyTauTy predTy boolTy (PredCtxt pred) `thenTc_`
-
- tcExpr e b1 `thenTc` \ (b1',lie2,result_ty) ->
- tcExpr e b2 `thenTc` \ (b2',lie3,b2Ty) ->
-
- unifyTauTy result_ty b2Ty (BranchCtxt b1 b2) `thenTc_`
-
- returnTc (If pred' b1' b2', plusLIE lie1 (plusLIE lie2 lie3), result_ty)
-
-tcExpr e (ListComp expr quals)
- = mkIdsWithPolyTyVarTys binders `thenNF_Tc` \ lve ->
- -- Binders of a list comprehension must be boxed.
- let
- new_e = growE_LVE e lve
- in
- tcQuals new_e quals `thenTc` \ (quals',lie1) ->
- tcExpr new_e expr `thenTc` \ (expr', lie2, ty) ->
- returnTc (ListComp expr' quals', plusLIE lie1 lie2, mkListTy ty)
+tcMonoExpr (HsSCC lbl expr) res_ty
+ = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) ->
+ returnTc (HsSCC lbl expr', lie)
+
+tcMonoExpr (HsLet binds expr) res_ty
+ = tcBindsAndThen
+ combiner
+ binds -- Bindings to check
+ tc_expr `thenTc` \ (expr', lie) ->
+ returnTc (expr', lie)
where
- binders = collectQualBinders quals
+ tc_expr = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) ->
+ returnTc (expr', lie)
+ 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 (caseCtxt in_expr) $
+
+ -- Typecheck the case alternatives first.
+ -- The case patterns tend to give good type info to use
+ -- when typechecking the scrutinee. For example
+ -- 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 matches res_ty `thenTc` \ (scrut_ty, matches', lie2) ->
+
+ tcAddErrCtxt (caseScrutCtxt scrut) (
+ tcMonoExpr scrut scrut_ty
+ ) `thenTc` \ (scrut',lie1) ->
+
+ returnTc (HsCase scrut' matches' src_loc, plusLIE lie1 lie2)
+
+tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (predCtxt pred) (
+ tcMonoExpr pred boolTy ) `thenTc` \ (pred',lie1) ->
+
+ tcMonoExpr b1 res_ty `thenTc` \ (b1',lie2) ->
+ tcMonoExpr b2 res_ty `thenTc` \ (b2',lie3) ->
+ returnTc (HsIf pred' b1' b2' src_loc, plusLIE lie1 (plusLIE lie2 lie3))
\end{code}
\begin{code}
-tcExpr e (ExplicitList [])
- = newPolyTyVarTy `thenNF_Tc` \ tyvar_ty ->
- returnTc (ExplicitListOut tyvar_ty [], nullLIE, mkListTy tyvar_ty)
-
-
-tcExpr e (ExplicitList exprs) -- Non-empty list
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) ->
- unifyTauTyList tys (ListCtxt exprs) `thenTc_`
- returnTc (ExplicitListOut elt_ty exprs', lie, mkListTy elt_ty)
-
-tcExpr e (ExplicitTuple exprs)
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys) ->
- returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys)
+tcMonoExpr expr@(HsDo do_or_lc stmts src_loc) res_ty
+ = tcDoStmts do_or_lc stmts src_loc res_ty
+\end{code}
-tcExpr e (ArithSeqIn seq@(From expr))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr `thenTc` \ (expr', lie, ty) ->
+\begin{code}
+tcMonoExpr in_expr@(ExplicitList exprs) res_ty -- Non-empty list
+ = unifyListTy res_ty `thenTc` \ elt_ty ->
+ mapAndUnzipTc (tc_elt elt_ty) exprs `thenTc` \ (exprs', lies) ->
+ returnTc (ExplicitListOut elt_ty exprs', plusLIEs lies)
+ where
+ tc_elt elt_ty expr
+ = 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 ->
+ 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)
+
+tcMonoExpr expr@(RecordCon con_name rbinds) res_ty
+ = tcAddErrCtxt (recordConCtxt expr) $
+ tcId con_name `thenNF_Tc` \ (con_expr, con_lie, con_tau) ->
let
- enum_from_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFrom")
+ (_, record_ty) = splitFunTys con_tau
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_id [ty] `thenNF_Tc` \ enum_from ->
-
- returnTc (ArithSeqOut (Var (mkInstId enum_from)) (From expr'),
- plusLIE (unitLIE enum_from) lie,
- mkListTy ty)
+ ASSERT( maybeToBool (splitAlgTyConApp_maybe record_ty ) )
+ unifyTauTy res_ty record_ty `thenTc_`
-tcExpr e (ArithSeqIn seq@(FromThen expr1 expr2))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
+ -- Check that the record bindings match the constructor
+ -- con_name is syntactically constrained to be a data constructor
+ tcLookupDataCon con_name `thenTc` \ (data_con, _, _) ->
+ let
+ bad_fields = badFields rbinds data_con
+ in
+ 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
- unifyTauTyList [ty1, ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ -- Typecheck the record bindings
+ tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+
+ let
+ missing_s_fields = missingStrictFields rbinds data_con
+ in
+ checkTcM (null missing_s_fields)
+ (mapNF_Tc (addErrTc . missingStrictFieldCon con_name) missing_s_fields `thenNF_Tc_`
+ returnNF_Tc ()) `thenNF_Tc_`
+ let
+ missing_fields = missingFields rbinds data_con
+ in
+ checkTcM (not (opt_WarnMissingFields && 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:
+--
+-- data T a b = MkT1 { fa :: a, fb :: b }
+-- | MkT2 { fa :: a, fc :: Int -> Int }
+-- | MkT3 { fd :: a }
+--
+-- upd :: T a b -> c -> T a c
+-- upd t x = t { fb = x}
+--
+-- The type signature on upd is correct (i.e. the result should not be (T a b))
+-- because upd should be equivalent to:
+--
+-- upd t x = case t of
+-- MkT1 p q -> MkT1 p x
+-- MkT2 a b -> MkT2 p b
+-- MkT3 d -> error ...
+--
+-- So we need to give a completely fresh type to the result record,
+-- and then constrain it by the fields that are *not* updated ("p" above).
+--
+-- Note that because MkT3 doesn't contain all the fields being updated,
+-- its RHS is simply an error, so it doesn't impose any type constraints
+--
+-- All this is done in STEP 4 below.
+
+tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty
+ = tcAddErrCtxt (recordUpdCtxt expr) $
+
+ -- STEP 0
+ -- Check that the field names are really field names
+ ASSERT( not (null rbinds) )
+ let
+ field_names = [field_name | (field_name, _, _) <- rbinds]
+ in
+ 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
+ (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)
+ in
+ tcInstTyVars con_tyvars `thenNF_Tc` \ (_, result_inst_tys, _) ->
+
+ -- STEP 2
+ -- 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
+ -- doesn't match the constructor.)
let
- enum_from_then_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThen")
+ result_record_ty = mkTyConApp tycon result_inst_tys
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_id [ty1] `thenNF_Tc` \ enum_from_then ->
+ unifyTauTy res_ty result_record_ty `thenTc_`
+ tcRecordBinds result_record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+
+ -- STEP 4
+ -- Use the un-updated fields to find a vector of booleans saying
+ -- which type arguments must be the same in updatee and result.
+ --
+ -- 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 | (sel_id, _, _) <- rbinds']
+ con_field_lbls_s = map dataConFieldLabels data_cons
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then))
- (FromThen expr1' expr2'),
- (unitLIE enum_from_then) `plusLIE` lie1 `plusLIE` lie2,
- mkListTy ty1)
+ -- A constructor is only relevant to this process if
+ -- it contains all the fields that are being updated
+ relevant_field_lbls_s = filter is_relevant con_field_lbls_s
+ is_relevant con_field_lbls = all (`elem` con_field_lbls) upd_field_lbls
-tcExpr e (ArithSeqIn seq@(FromTo expr1 expr2))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
+ non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls
+ common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls)
- unifyTauTyList [ty1,ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ 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
+ in
+ mapNF_Tc mk_inst_ty (zip con_tyvars result_inst_tys) `thenNF_Tc` \ inst_tys ->
+
+ -- STEP 5
+ -- Typecheck the expression to be updated
let
- enum_from_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromTo")
+ record_ty = mkTyConApp tycon inst_tys
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_to_id [ty1] `thenNF_Tc` \ enum_from_to ->
- returnTc (ArithSeqOut (Var (mkInstId enum_from_to))
- (FromTo expr1' expr2'),
- (unitLIE enum_from_to) `plusLIE` lie1 `plusLIE` lie2,
- mkListTy ty1)
-
-tcExpr e (ArithSeqIn seq@(FromThenTo expr1 expr2 expr3))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
- tcExpr e expr3 `thenTc` \ (expr3',lie3,ty3) ->
-
- unifyTauTyList [ty1,ty2,ty3] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ tcMonoExpr record_expr record_ty `thenTc` \ (record_expr', record_lie) ->
+
+ -- STEP 6
+ -- Figure out the LIE we need. We have to generate some
+ -- dictionaries for the data type context, since we are going to
+ -- do some construction.
+ --
+ -- What dictionaries do we need? For the moment we assume that all
+ -- data constructors have the same context, and grab it from the first
+ -- constructor. If they have varying contexts then we'd have to
+ -- union the ones that could participate in the update.
let
- enum_from_then_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThenTo")
+ (tyvars, theta, _, _, _, _) = dataConSig (head data_cons)
+ inst_env = mkTopTyVarSubst tyvars result_inst_tys
+ theta' = substClasses inst_env theta
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_to_id [ty1] `thenNF_Tc` \ enum_from_then_to ->
+ newClassDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) ->
+
+ -- Phew!
+ returnTc (RecordUpdOut record_expr' result_record_ty dicts rbinds',
+ 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) ->
+
+ tcLookupValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq)
+ sel_id [elt_ty] `thenNF_Tc` \ (lie2, enum_from_id) ->
+
+ returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'),
+ lie1 `plusLIE` lie2)
+
+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) ->
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then_to))
+ returnTc (ArithSeqOut (HsVar enum_from_then_id)
+ (FromThen expr1' expr2'),
+ lie1 `plusLIE` lie2 `plusLIE` lie3)
+
+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) ->
+
+ returnTc (ArithSeqOut (HsVar enum_from_to_id)
+ (FromTo expr1' expr2'),
+ lie1 `plusLIE` lie2 `plusLIE` lie3)
+
+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'),
- (unitLIE enum_from_then_to) `plusLIE` lie1 `plusLIE` lie2 `plusLIE` lie3,
- mkListTy ty1)
+ lie1 `plusLIE` lie2 `plusLIE` lie3 `plusLIE` lie4)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcExpr e (ExprWithTySig expr poly_ty)
- = tcExpr e expr `thenTc` \ (texpr, lie, tau_ty) ->
- babyTcMtoTcM (tcPolyType (getE_CE e) (getE_TCE e) nullTVE poly_ty) `thenTc` \ sigma_sig ->
-
- -- Check the tau-type part
- specTy SignatureOrigin sigma_sig `thenNF_Tc` \ (sig_tyvars, sig_dicts, sig_tau) ->
- unifyTauTy tau_ty sig_tau (ExprSigCtxt expr sig_tau) `thenTc_`
-
- -- Check the type variables of the signature
- applyTcSubstAndCollectTyVars (tvOfE e) `thenNF_Tc` \ env_tyvars ->
- checkSigTyVars env_tyvars sig_tyvars sig_tau tau_ty (ExprSigCtxt expr sig_tau)
- `thenTc` \ sig_tyvars' ->
-
- -- Check overloading constraints
- tcSimplifyAndCheck
- False {- Not top level -}
- env_tyvars sig_tyvars'
- sig_dicts (unMkLIE lie)
- (ExprSigCtxt expr sigma_sig) `thenTc_`
-
- -- If everything is ok, return the stuff unchanged, except for
- -- the effect of any substutions etc. We simply discard the
- -- result of the tcSimplifyAndCheck, except for any default
- -- resolution it may have done, which is recorded in the
- -- substitution.
- returnTc (texpr, lie, tau_ty)
+tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty
+ = tcSetErrCtxt (exprSigCtxt in_expr) $
+ tcHsSigType poly_ty `thenTc` \ sig_tc_ty ->
+
+ if not (isForAllTy sig_tc_ty) then
+ -- Easy case
+ unifyTauTy sig_tc_ty res_ty `thenTc_`
+ tcMonoExpr expr sig_tc_ty
+
+ else -- Signature is polymorphic
+ tcPolyExpr expr sig_tc_ty `thenTc` \ (_, _, expr, expr_ty, lie) ->
+
+ -- Now match the signature type with res_ty.
+ -- We must not do this earlier, because res_ty might well
+ -- mention variables free in the environment, and we'd get
+ -- bogus complaints about not being able to for-all the
+ -- sig_tyvars
+ unifyTauTy res_ty expr_ty `thenTc_`
+
+ -- 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
+ -- resolution it may have done, which is recorded in the
+ -- substitution.
+ returnTc (expr, lie)
+\end{code}
+
+Implicit Parameter bindings.
+
+\begin{code}
+tcMonoExpr (HsWith expr binds) res_ty
+ = tcMonoExpr expr res_ty `thenTc` \ (expr', lie) ->
+ tcIPBinds binds `thenTc` \ (binds', types, lie2) ->
+ partitionPredsOfLIE isBound lie `thenTc` \ (ips, lie', dict_binds) ->
+ pprTrace "tcMonoExpr With" (ppr (ips, lie', dict_binds)) $
+ let expr'' = if nullMonoBinds dict_binds
+ then expr'
+ else HsLet (mkMonoBind (revBinds dict_binds) [] NonRecursive)
+ expr'
+ in
+ tcCheckIPBinds binds' types ips `thenTc_`
+ returnTc (HsWith expr'' binds', lie' `plusLIE` lie2)
+ where isBound p
+ = case ipName_maybe p of
+ Just n -> n `elem` names
+ Nothing -> False
+ names = map fst binds
+ -- revBinds is used because tcSimplify outputs the bindings
+ -- out-of-order. it's not a problem elsewhere because these
+ -- bindings are normally used in a recursive let
+ -- ZZ probably need to find a better solution
+ revBinds (b1 `AndMonoBinds` b2) =
+ (revBinds b2) `AndMonoBinds` (revBinds b1)
+ revBinds b = b
+
+tcIPBinds ((name, expr) : binds)
+ = newTyVarTy_OpenKind `thenTc` \ ty ->
+ tcGetSrcLoc `thenTc` \ loc ->
+ let id = ipToId name ty loc in
+ tcMonoExpr expr ty `thenTc` \ (expr', lie) ->
+ zonkTcType ty `thenTc` \ ty' ->
+ tcIPBinds binds `thenTc` \ (binds', types, lie2) ->
+ returnTc ((id, expr') : binds', ty : types, lie `plusLIE` lie2)
+tcIPBinds [] = returnTc ([], [], emptyLIE)
+
+tcCheckIPBinds binds types ips
+ = foldrTc tcCheckIPBind (getIPsOfLIE ips) (zip binds types)
+
+-- ZZ how do we use the loc?
+tcCheckIPBind bt@((v, _), t1) ((n, t2) : ips) | getName v == n
+ = unifyTauTy t1 t2 `thenTc_`
+ tcCheckIPBind bt ips `thenTc` \ ips' ->
+ returnTc ips'
+tcCheckIPBind bt (ip : ips)
+ = tcCheckIPBind bt ips `thenTc` \ ips' ->
+ returnTc (ip : ips')
+tcCheckIPBind bt []
+ = returnTc []
+\end{code}
+
+Typecheck expression which in most cases will be an Id.
+
+\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)
\end{code}
%************************************************************************
%* *
-\subsection{Data Parallel Expressions (DPH only)}
+\subsection{@tcApp@ typchecks an application}
%* *
%************************************************************************
-Constraints enforced by the Static semantics for ParallelZF
-$exp_1$ = << $exp_2$ | quals >>
+\begin{code}
-\begin{enumerate}
-\item The type of the expression $exp_1$ is <<$exp_2$>>
-\item The type of $exp_2$ must be in the class {\tt Processor}
-\end{enumerate}
+tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
+ -> TcType -- Expected result type of application
+ -> TcM s (TcExpr, [TcExpr], -- Translated fun and args
+ LIE)
-\begin{code}
-#ifdef DPH
-tcExpr e (ParallelZF expr quals)
- = let binders = collectParQualBinders quals in
- mkIdsWithPolyTyVarTys binders `thenNF_Tc` (\ lve ->
- let e' = growE_LVE e lve in
- tcParQuals e' quals `thenTc` (\ (quals',lie1) ->
- tcExpr e' expr `thenTc` (\ (expr', lie2,ty) ->
- getSrcLocTc `thenNF_Tc` (\ src_loc ->
- if (isProcessorTy ty) then
- returnTc (ParallelZF expr' quals',
- plusLIE lie1 lie2 ,
- mkPodTy ty)
- else
- failTc (podCompLhsError ty src_loc)
- ))))
-#endif {- Data Parallel Haskell -}
-\end{code}
+tcApp fun args res_ty
+ = -- First type-check the function
+ tcExpr_id fun `thenTc` \ (fun', lie_fun, fun_ty) ->
-Constraints enforced by the Static semantics for Explicit Pods
-exp = << $exp_1$ ... $exp_n$>> (where $n >= 0$)
+ tcAddErrCtxt (wrongArgsCtxt "too many" fun args) (
+ split_fun_ty fun_ty (length args)
+ ) `thenTc` \ (expected_arg_tys, actual_result_ty) ->
-\begin{enumerate}
-\item The type of the all the expressions in the Pod must be the same.
-\item The type of an expression in a POD must be in class {\tt Processor}
-\end{enumerate}
+ -- Unify with expected result before type-checking the args
+ -- This is when we might detect a too-few args situation
+ tcAddErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty) (
+ unifyTauTy res_ty actual_result_ty
+ ) `thenTc_`
-\begin{code}
-#ifdef DPH
-tcExpr e (ExplicitPodIn exprs)
- = panic "Ignoring explicit PODs for the time being"
-{-
- = tcExprs e exprs `thenTc` (\ (exprs',lie,tys) ->
- newPolyTyVarTy `thenNF_Tc` (\ elt_ty ->
- newDict processorClass elt_ty `thenNF_Tc` (\ procDict ->
- let
- procLie = mkLIEFromDicts procDict
- in
- unifyTauTyList (elt_ty:tys) (PodCtxt exprs) `thenTc_`
-
- returnTc ((App
- (DictApp
- (TyApp (Var toPodId) [elt_ty])
- procDict)
- (ExplicitListOut elt_ty exprs')),
- plusLIE procLie lie,
- mkPodTy elt_ty)
- ))) -}
-#endif {- Data Parallel Haskell -}
+ -- Now typecheck the args
+ mapAndUnzipTc (tcArg fun)
+ (zip3 args expected_arg_tys [1..]) `thenTc` \ (args', lie_args_s) ->
+
+ -- 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_`
+
+ returnTc (fun', args', lie_fun `plusLIE` plusLIEs lie_args_s)
+
+
+-- If an error happens we try to figure out whether the
+-- function has been given too many or too few arguments,
+-- and say so
+checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env
+ = zonkTcType expected_res_ty `thenNF_Tc` \ exp_ty' ->
+ zonkTcType actual_res_ty `thenNF_Tc` \ act_ty' ->
+ let
+ (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''
+
+ message | length exp_args < length act_args = wrongArgsCtxt "too few" fun args
+ | length exp_args > length act_args = wrongArgsCtxt "too many" fun args
+ | otherwise = appCtxt fun args
+ in
+ returnNF_Tc (env2, message)
+
+
+split_fun_ty :: TcType -- The type of the function
+ -> Int -- Number of arguments
+ -> TcM s ([TcType], -- Function argument types
+ TcType) -- Function result types
+
+split_fun_ty fun_ty 0
+ = returnTc ([], fun_ty)
+
+split_fun_ty fun_ty n
+ = -- Expect the function to have type A->B
+ unifyFunTy fun_ty `thenTc` \ (arg_ty, res_ty) ->
+ split_fun_ty res_ty (n-1) `thenTc` \ (arg_tys, final_res_ty) ->
+ returnTc (arg_ty:arg_tys, final_res_ty)
\end{code}
\begin{code}
-#ifdef DPH
-tcExpr e (ExplicitProcessor exprs expr)
- = tcPidExprs e exprs `thenTc` (\ (exprs',lie1,tys) ->
- tcExpr e expr `thenTc` (\ (expr',lie2,ty) ->
- returnTc (ExplicitProcessor exprs' expr',
- plusLIE lie1 lie2,
- mkProcessorTy tys ty)
- ))
-#endif {- Data Parallel Haskell -}
+tcArg :: RenamedHsExpr -- The function (for error messages)
+ -> (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) $
+ tcExpr arg expected_arg_ty
\end{code}
+
%************************************************************************
%* *
-\subsection{@tcExprs@ typechecks a {\em list} of expressions}
+\subsection{@tcId@ typchecks an identifier occurrence}
%* *
%************************************************************************
-ToDo: Possibly find a version of a listTc TcM which would pass the
-appropriate functions for the LIE.
+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}
-tcExprs :: E -> [RenamedExpr] -> TcM ([TypecheckedExpr],LIE,[TauType])
+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))
+
+ Nothing -> tcLookupValue name `thenNF_Tc` \ id ->
+ tcInstId id `thenNF_Tc` \ (tyvars, theta, tau) ->
+ instantiate_it2 (OccurrenceOf id) (HsVar id) tyvars theta tau
+
+ 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
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{@tcDoStmts@ typechecks a {\em list} of do statements}
+%* *
+%************************************************************************
-tcExprs e [] = returnTc ([], nullLIE, [])
-tcExprs e (expr:exprs)
- = tcExpr e expr `thenTc` \ (expr', lie1, ty) ->
- tcExprs e exprs `thenTc` \ (exprs', lie2, tys) ->
- returnTc (expr':exprs', plusLIE lie1 lie2, ty:tys)
+\begin{code}
+tcDoStmts do_or_lc stmts src_loc res_ty
+ = -- get the Monad and MonadZero classes
+ -- create type consisting of a fresh monad tyvar
+ 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_`
+
+ 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,
+ -- not only for typechecker efficiency, but also because otherwise during
+ -- simplification we end up with silly stuff like
+ -- then = case d of (t,r) -> t
+ -- 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) ->
+ let
+ monad_lie = then_lie `plusLIE` return_lie `plusLIE` fail_lie
+ in
+ returnTc (HsDoOut do_or_lc stmts' return_id then_id fail_id res_ty src_loc,
+ stmts_lie `plusLIE` monad_lie)
\end{code}
%************************************************************************
%* *
-\subsection{@tcApp@ typchecks an application}
+\subsection{Record bindings}
%* *
%************************************************************************
+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.
+
+2. Instantiate this type
+
+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.
+
+4. Type check the value using tcArg, passing tau 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}
-tcApp :: (TypecheckedExpr -> [TypecheckedExpr] -> TypecheckedExpr) -- Result builder
- -> E
- -> RenamedExpr
- -> [RenamedExpr]
- -> TcM (TypecheckedExpr, LIE, UniType)
-
-tcApp build_result_expression e orig_fun arg_exprs
- = tcExpr' e orig_fun (length arg_exprs)
- `thenTc` \ (fun', lie_fun, fun_ty) ->
- unify_fun 1 fun' lie_fun arg_exprs fun_ty
- where
- -- Used only in the error message
- maybe_fun_id = case orig_fun of
- Var name -> Just (lookupE_Value e name)
- other -> Nothing
-
- unify_args :: Int -- Current argument number
- -> TypecheckedExpr -- Current rebuilt expression
- -> LIE -- Corresponding LIE
- -> [RenamedExpr] -- Remaining args
- -> [TauType] -- Remaining arg types
- -> TauType -- result type
- -> TcM (TypecheckedExpr, LIE, UniType)
-
- unify_args arg_no fun lie (arg:args) (arg_ty:arg_tys) fun_res_ty
- = tcExpr e arg `thenTc` \ (arg', lie_arg, actual_arg_ty) ->
-
- -- These applyTcSubstToTy's are just to improve the error message...
- applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' ->
- applyTcSubstToTy arg_ty `thenNF_Tc` \ arg_ty' ->
+tcRecordBinds
+ :: TcType -- Expected type of whole record
+ -> RenamedRecordBinds
+ -> 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)
+ = 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
+ -- before calling tcRecordBinds
+
+ tcInstId sel_id `thenNF_Tc` \ (_, _, tau) ->
+
+ -- Record selectors all have type
+ -- forall a1..an. T a1 .. an -> tau
+ ASSERT( maybeToBool (splitFunTy_maybe tau) )
let
- err_ctxt = FunAppCtxt orig_fun maybe_fun_id arg arg_ty' actual_arg_ty' arg_no
+ -- Selector must have type RecordType -> FieldType
+ Just (record_ty, field_ty) = splitFunTy_maybe tau
in
- matchArgTy e arg_ty' arg' lie_arg actual_arg_ty' err_ctxt
- `thenTc` \ (arg'', lie_arg') ->
+ 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
+ = [field_name | (field_name, _, _) <- rbinds,
+ not (field_name `elem` field_names)
+ ]
+ where
+ field_names = map fieldLabelName (dataConFieldLabels data_con)
+
+missingStrictFields rbinds data_con
+ = [ fn | fn <- strict_field_names,
+ not (fn `elem` field_names_used)
+ ]
+ where
+ field_names_used = [ field_name | (field_name, _, _) <- rbinds ]
+ strict_field_names = mapMaybe isStrict field_info
- unify_args (arg_no+1) (App fun arg'') (lie `plusLIE` lie_arg') args arg_tys fun_res_ty
+ isStrict (fl, MarkedStrict) = Just (fieldLabelName fl)
+ isStrict _ = Nothing
- unify_args arg_no fun lie [] arg_tys fun_res_ty
- = -- We've run out of actual arguments. Check that none of
- -- arg_tys has a for-all at the top. For example, "build" on
- -- its own is no good; it must be applied to something.
- let
- result_ty = glueTyArgs arg_tys fun_res_ty
- in
- getSrcLocTc `thenNF_Tc` \ loc ->
- checkTc (not (isTauTy result_ty))
- (underAppliedTyErr result_ty loc) `thenTc_`
- returnTc (fun, lie, result_ty)
+ field_info = zip (dataConFieldLabels data_con)
+ (dataConStrictMarks data_con)
- -- When we run out of arg_tys we go back to unify_fun in the hope
- -- that our unification work may have shown up some more arguments
- unify_args arg_no fun lie args [] fun_res_ty
- = unify_fun arg_no fun lie args fun_res_ty
+missingFields rbinds data_con
+ = [ fn | fn <- non_strict_field_names, not (fn `elem` field_names_used) ]
+ where
+ field_names_used = [ field_name | (field_name, _, _) <- rbinds ]
+ -- missing strict fields have already been flagged as
+ -- being so, so leave them out here.
+ non_strict_field_names = mapMaybe isn'tStrict field_info
- unify_fun :: Int -- Current argument number
- -> TypecheckedExpr -- Current rebuilt expression
- -> LIE -- Corresponding LIE
- -> [RenamedExpr] -- Remaining args
- -> TauType -- Remaining function type
- -> TcM (TypecheckedExpr, LIE, UniType)
+ isn'tStrict (fl, MarkedStrict) = Nothing
+ isn'tStrict (fl, _) = Just (fieldLabelName fl)
- unify_fun arg_no fun lie args fun_ty
- = -- Find out as much as possible about the function
- applyTcSubstToTy fun_ty `thenNF_Tc` \ fun_ty' ->
+ field_info = zip (dataConFieldLabels data_con)
+ (dataConStrictMarks data_con)
- -- Now see whether it has any arguments
- case (splitTyArgs fun_ty') of
+\end{code}
- ([], _) -> -- Function has no arguments left
+%************************************************************************
+%* *
+\subsection{@tcMonoExprs@ typechecks a {\em list} of expressions}
+%* *
+%************************************************************************
+
+\begin{code}
+tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM s ([TcExpr], LIE)
- newOpenTyVarTy `thenNF_Tc` \ result_ty ->
- tcExprs e args `thenTc` \ (args', lie_args, arg_tys) ->
+tcMonoExprs [] [] = returnTc ([], emptyLIE)
+tcMonoExprs (expr:exprs) (ty:tys)
+ = tcMonoExpr expr ty `thenTc` \ (expr', lie1) ->
+ tcMonoExprs exprs tys `thenTc` \ (exprs', lie2) ->
+ returnTc (expr':exprs', lie1 `plusLIE` lie2)
+\end{code}
- -- At this point, a unification error must mean the function is
- -- being applied to too many arguments.
- unifyTauTy fun_ty' (glueTyArgs arg_tys result_ty)
- (TooManyArgsCtxt orig_fun) `thenTc_`
- returnTc (build_result_expression fun args',
- lie `plusLIE` lie_args,
- result_ty)
+% =================================================
- (fun_arg_tys, fun_res_ty) -> -- Function has non-empty list of argument types
+Errors and contexts
+~~~~~~~~~~~~~~~~~~~
- unify_args arg_no fun lie args fun_arg_tys fun_res_ty
+Mini-utils:
+\begin{code}
+pp_nest_hang :: String -> SDoc -> SDoc
+pp_nest_hang lbl stuff = nest 2 (hang (text lbl) 4 stuff)
\end{code}
+Boring and alphabetical:
\begin{code}
-matchArgTy :: E
- -> UniType -- Expected argument type
- -> TypecheckedExpr -- Type checked argument
- -> LIE -- Actual argument LIE
- -> UniType -- Actual argument type
- -> UnifyErrContext
- -> TcM (TypecheckedExpr, -- The incoming type checked arg,
- -- possibly wrapped in a big lambda
- LIE) -- Possibly reduced somewhat
-
-matchArgTy e expected_arg_ty arg_expr actual_arg_lie actual_arg_ty err_ctxt
- | isForAllTy expected_arg_ty
- = -- Ha! The argument type of the function is a for-all type,
- -- An example of rank-2 polymorphism.
-
- -- This applyTcSubstToTy is just to improve the error message..
-
- applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' ->
-
- -- Instantiate the argument type
- -- ToDo: give this a real origin
- specTy UnknownOrigin expected_arg_ty `thenNF_Tc` \ (arg_tyvars, arg_lie, arg_tau) ->
-
- if not (null arg_lie) then
- -- Paranoia check
- panic "Non-null overloading in tcApp"
- else
- -- Assert: arg_lie = []
+arithSeqCtxt expr
+ = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr)
- unifyTauTy arg_tau actual_arg_ty' err_ctxt `thenTc_`
+caseCtxt expr
+ = hang (ptext SLIT("In the case expression:")) 4 (ppr expr)
- -- Check that the arg_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)
- -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool))
- -- for (newVar True), with s fresh. Then we unify with the runST's arg type
- -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool.
- -- So now s' isn't unconstrained because it's linked to a.
- -- Conclusion: include the free vars of the expected arg type in the
- -- list of "free vars" for the signature check.
- applyTcSubstAndCollectTyVars
- (tvOfE e `unionLists`
- extractTyVarsFromTy expected_arg_ty) `thenNF_Tc` \ free_tyvars ->
- checkSigTyVars free_tyvars arg_tyvars arg_tau actual_arg_ty rank2_err_ctxt
- `thenTc` \ arg_tyvars' ->
-
- -- Check that there's no overloading involved
- -- Even if there isn't, there may be some Insts which mention the arg_tyvars,
- -- but which, on simplification, don't actually need a dictionary involving
- -- the tyvar. So we have to do a proper simplification right here.
- let insts = unMkLIE actual_arg_lie
- in
- applyTcSubstToInsts insts `thenNF_Tc` \ insts' ->
+caseScrutCtxt expr
+ = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr)
+
+exprSigCtxt expr
+ = hang (ptext SLIT("In an expression with a type signature:"))
+ 4 (ppr expr)
+
+listCtxt expr
+ = hang (ptext SLIT("In the list element:")) 4 (ppr expr)
- tcSimplifyRank2 arg_tyvars' insts' rank2_err_ctxt `thenTc` \ (free_insts, inst_binds) ->
+predCtxt expr
+ = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr)
- -- This Let 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.
- returnTc (TyLam arg_tyvars' (Let (mk_binds inst_binds) arg_expr), mkLIE free_insts)
+sectionRAppCtxt expr
+ = hang (ptext SLIT("In the right section:")) 4 (ppr expr)
- | otherwise
- = -- The ordinary, non-rank-2 polymorphic case
- unifyTauTy expected_arg_ty actual_arg_ty err_ctxt `thenTc_`
- returnTc (arg_expr, actual_arg_lie)
+sectionLAppCtxt expr
+ = hang (ptext SLIT("In the left section:")) 4 (ppr expr)
+funAppCtxt fun arg arg_no
+ = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"),
+ quotes (ppr fun) <> text ", namely"])
+ 4 (quotes (ppr arg))
+
+wrongArgsCtxt too_many_or_few fun args
+ = hang (ptext SLIT("Probable cause:") <+> quotes (ppr fun)
+ <+> ptext SLIT("is applied to") <+> text too_many_or_few
+ <+> ptext SLIT("arguments in the call"))
+ 4 (parens (ppr the_app))
where
- rank2_err_ctxt = Rank2ArgCtxt arg_expr expected_arg_ty
+ the_app = foldl HsApp fun args -- Used in error messages
- mk_binds [] = EmptyBinds
- mk_binds ((inst,rhs):inst_binds) = (SingleBind (NonRecBind (VarMonoBind (mkInstId inst) rhs)))
- `ThenBinds`
- mk_binds inst_binds
-\end{code}
+appCtxt fun args
+ = ptext SLIT("In the application") <+> quotes (ppr the_app)
+ where
+ the_app = foldl HsApp fun args -- Used in error messages
-This version only does not check for 2nd order if it is applied.
+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")])
-\begin{code}
-tcExpr' :: E -> RenamedExpr -> Int -> TcM (TypecheckedExpr,LIE,UniType)
+rank2ArgCtxt arg expected_arg_ty
+ = ptext SLIT("In a polymorphic function argument:") <+> ppr arg
+
+badFieldsUpd rbinds
+ = hang (ptext SLIT("No constructor has all these fields:"))
+ 4 (pprQuotedList fields)
+ where
+ fields = [field | (field, _, _) <- rbinds]
+
+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 -> Name -> SDoc
+missingStrictFieldCon con field
+ = hsep [ptext SLIT("Constructor") <+> quotes (ppr con),
+ ptext SLIT("does not have the required strict field"), quotes (ppr field)]
-tcExpr' e v@(Var name) n
- | n > 0 = specId (lookupE_Value e name) `thenNF_Tc` \ (expr, lie, ty) ->
- returnTc (expr, lie, ty)
-tcExpr' e exp n = tcExpr e exp
+missingFieldCon :: Name -> Name -> SDoc
+missingFieldCon con field
+ = hsep [ptext SLIT("Field") <+> quotes (ppr field),
+ ptext SLIT("is not initialised")]
\end{code}
projects / ghc-hetmet.git / blobdiff