%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
%
-\section[TcExpr]{TcExpr}
+\section[TcExpr]{Typecheck an expression}
\begin{code}
#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 AbsSyn -- the stuff being typechecked
+module TcExpr ( tcExpr ) where
+IMP_Ubiq()
-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 HsSyn ( HsExpr(..), Qualifier(..), Stmt(..),
+ HsBinds(..), Bind(..), MonoBinds(..),
+ ArithSeqInfo(..), HsLit(..), Sig, GRHSsAndBinds,
+ Match, Fake, InPat, OutPat, PolyType,
+ failureFreePat, collectPatBinders )
+import RnHsSyn ( SYN_IE(RenamedHsExpr), SYN_IE(RenamedQual),
+ SYN_IE(RenamedStmt), SYN_IE(RenamedRecordBinds),
+ RnName{-instance Outputable-}
+ )
+import TcHsSyn ( SYN_IE(TcExpr), SYN_IE(TcQual), SYN_IE(TcStmt),
+ TcIdOcc(..), SYN_IE(TcRecordBinds),
+ mkHsTyApp
)
-import AbsUniType
-import E
-import CE ( lookupCE )
-
-#ifndef DPH
-import Errors ( badMatchErr, UnifyErrContext(..) )
-#else
-import Errors ( badMatchErr, podCompLhsError, UnifyErrContext(..) )
-#endif {- Data Parallel Haskell -}
-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 TcMonad hiding ( rnMtoTcM )
+import Inst ( Inst, InstOrigin(..), OverloadedLit(..),
+ SYN_IE(LIE), emptyLIE, plusLIE, plusLIEs, newOverloadedLit,
+ newMethod, newMethodWithGivenTy, newDicts )
+import TcBinds ( tcBindsAndThen )
+import TcEnv ( tcLookupLocalValue, tcLookupGlobalValue, tcLookupClassByKey,
+ tcLookupGlobalValueByKey, newMonoIds, tcGetGlobalTyVars,
+ tcExtendGlobalTyVars
+ )
+import SpecEnv ( SpecEnv )
import TcMatches ( tcMatchesCase, tcMatch )
-import TcPolyType ( tcPolyType )
-import TcQuals ( tcQuals )
+import TcMonoType ( tcPolyType )
+import TcPat ( tcPat )
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 TcType ( SYN_IE(TcType), TcMaybe(..),
+ tcInstId, tcInstType, tcInstSigTcType,
+ tcInstSigType, tcInstTcType, tcInstTheta,
+ newTyVarTy, zonkTcTyVars, zonkTcType )
+import TcKind ( TcKind )
+
+import Class ( SYN_IE(Class), classSig )
+import FieldLabel ( fieldLabelName )
+import Id ( idType, dataConFieldLabels, dataConSig, SYN_IE(Id), GenId )
+import Kind ( Kind, mkBoxedTypeKind, mkTypeKind, mkArrowKind )
+import GenSpecEtc ( checkSigTyVars )
+import Name ( Name{-instance Eq-} )
+import Type ( mkFunTy, mkAppTy, mkTyVarTy, mkTyVarTys, mkRhoTy,
+ getTyVar_maybe, getFunTy_maybe, instantiateTy,
+ splitForAllTy, splitRhoTy, splitSigmaTy, splitFunTy,
+ isTauTy, mkFunTys, tyVarsOfType, getForAllTy_maybe,
+ getAppDataTyCon, maybeAppDataTyCon
+ )
+import TyVar ( GenTyVar, SYN_IE(TyVarSet), unionTyVarSets, mkTyVarSet )
+import TysPrim ( intPrimTy, charPrimTy, doublePrimTy,
+ floatPrimTy, addrPrimTy, realWorldTy
+ )
+import TysWiredIn ( addrTy,
+ boolTy, charTy, stringTy, mkListTy,
+ mkTupleTy, mkPrimIoTy, stDataCon
+ )
+import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists, unifyFunTy )
+import Unique ( Unique, cCallableClassKey, cReturnableClassKey,
+ enumFromClassOpKey, enumFromThenClassOpKey,
+ enumFromToClassOpKey, enumFromThenToClassOpKey,
+ thenMClassOpKey, zeroClassOpKey
+ )
+import Outputable ( interpp'SP )
+import PprType ( GenType, GenTyVar ) -- Instances
+import Maybes ( maybeToBool )
+import Pretty
import Util
+\end{code}
-tcExpr :: E -> RenamedExpr -> TcM (TypecheckedExpr, LIE, UniType)
+\begin{code}
+tcExpr :: RenamedHsExpr -> TcM s (TcExpr s, LIE s, TcType s)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcExpr e (Var name)
- = specId (lookupE_Value e name) `thenNF_Tc` \ stuff@(expr, lie, ty) ->
+tcExpr (HsVar name)
+ = tcId name `thenNF_Tc` \ (expr', lie, res_ty) ->
- -- 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
+ -- 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 res_ty)
+ (lurkingRank2Err name res_ty) `thenTc_`
- checkTc (not (isTauTy ty)) (error "tcExpr Var: MISSING ERROR MESSAGE") -- ToDo:
- `thenTc_`
-
- returnTc stuff
+ returnTc (expr', lie, res_ty)
\end{code}
%************************************************************************
Overloaded literals.
\begin{code}
-tcExpr e (Lit lit@(IntLit i))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- newPolyTyVarTy `thenNF_Tc` \ ty ->
- let
- from_int = lookupE_ClassOpByKey e numClassKey SLIT("fromInt")
- from_integer = lookupE_ClassOpByKey e numClassKey SLIT("fromInteger")
- in
- newOverloadedLit (LiteralOrigin lit loc)
- (OverloadedIntegral i from_int from_integer)
- ty
- `thenNF_Tc` \ over_lit ->
+tcExpr (HsLit (HsInt i))
+ = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty ->
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
+ newOverloadedLit (LiteralOrigin (HsInt i))
+ (OverloadedIntegral i)
+ ty `thenNF_Tc` \ (lie, over_lit_id) ->
-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 ->
+ returnTc (HsVar over_lit_id, lie, ty)
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
+tcExpr (HsLit (HsFrac f))
+ = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty ->
-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"
- in
- newPolyTyVarTy `thenNF_Tc` \ ty ->
-
- newDict (LitLitOrigin loc (_UNPK_ s)) cCallableClass ty `thenNF_Tc` \ dict ->
+ newOverloadedLit (LiteralOrigin (HsFrac f))
+ (OverloadedFractional f)
+ ty `thenNF_Tc` \ (lie, over_lit_id) ->
- returnTc (Lit (LitLitLit s ty), mkLIE [dict], ty)
+ returnTc (HsVar over_lit_id, lie, ty)
+
+tcExpr (HsLit lit@(HsLitLit s))
+ = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
+ newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ ty ->
+ newDicts (LitLitOrigin (_UNPK_ s))
+ [(cCallableClass, ty)] `thenNF_Tc` \ (dicts, _) ->
+ returnTc (HsLitOut lit ty, dicts, ty)
\end{code}
Primitive literals:
\begin{code}
-tcExpr e (Lit (CharPrimLit c))
- = returnTc (Lit (CharPrimLit c), nullLIE, charPrimTy)
+tcExpr (HsLit lit@(HsCharPrim c))
+ = returnTc (HsLitOut lit charPrimTy, emptyLIE, charPrimTy)
-tcExpr e (Lit (StringPrimLit s))
- = returnTc (Lit (StringPrimLit s), nullLIE, addrPrimTy)
+tcExpr (HsLit lit@(HsStringPrim s))
+ = returnTc (HsLitOut lit addrPrimTy, emptyLIE, addrPrimTy)
-tcExpr e (Lit (IntPrimLit i))
- = returnTc (Lit (IntPrimLit i), nullLIE, intPrimTy)
+tcExpr (HsLit lit@(HsIntPrim i))
+ = returnTc (HsLitOut lit intPrimTy, emptyLIE, intPrimTy)
-tcExpr e (Lit (FloatPrimLit f))
- = returnTc (Lit (FloatPrimLit f), nullLIE, floatPrimTy)
+tcExpr (HsLit lit@(HsFloatPrim f))
+ = returnTc (HsLitOut lit floatPrimTy, emptyLIE, floatPrimTy)
-tcExpr e (Lit (DoublePrimLit d))
- = returnTc (Lit (DoublePrimLit d), nullLIE, doublePrimTy)
+tcExpr (HsLit lit@(HsDoublePrim d))
+ = returnTc (HsLitOut lit doublePrimTy, emptyLIE, doublePrimTy)
\end{code}
Unoverloaded literals:
\begin{code}
-tcExpr e (Lit (CharLit c))
- = returnTc (Lit (CharLit c), nullLIE, charTy)
+tcExpr (HsLit lit@(HsChar c))
+ = returnTc (HsLitOut lit charTy, emptyLIE, charTy)
-tcExpr e (Lit (StringLit str))
- = returnTc (Lit (StringLit str), nullLIE, stringTy)
+tcExpr (HsLit lit@(HsString str))
+ = returnTc (HsLitOut lit stringTy, emptyLIE, stringTy)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcExpr e (Lam match)
- = tcMatch e match `thenTc` \ (match',lie,ty) ->
- returnTc (Lam match',lie,ty)
+tcExpr (HsPar expr) -- preserve parens so printing needn't guess where they go
+ = tcExpr expr
+
+tcExpr (NegApp expr neg) = tcExpr (HsApp neg expr)
-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
+tcExpr (HsLam match)
+ = tcMatch match `thenTc` \ (match',lie,ty) ->
+ returnTc (HsLam match', lie, ty)
+
+tcExpr (HsApp e1 e2) = accum e1 [e2]
+ where
+ accum (HsApp e1 e2) args = accum e1 (e2:args)
+ accum fun args
+ = tcApp fun args `thenTc` \ (fun', args', lie, res_ty) ->
+ returnTc (foldl HsApp fun' args', lie, res_ty)
-- equivalent to (op e1) e2:
-tcExpr e (OpApp e1 op e2)
- = tcApp (\fun [arg1,arg2] -> OpApp arg1 fun arg2) e op [e1,e2]
+tcExpr (OpApp arg1 op arg2)
+ = tcApp op [arg1,arg2] `thenTc` \ (op', [arg1', arg2'], lie, res_ty) ->
+ returnTc (OpApp arg1' op' arg2', lie, res_ty)
\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]
+tcExpr in_expr@(SectionL arg op)
+ = tcApp op [arg] `thenTc` \ (op', [arg'], lie, res_ty) ->
+
+ -- 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!
+ newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 ->
+ newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 ->
+ tcAddErrCtxt (sectionLAppCtxt in_expr) $
+ unifyTauTy (mkFunTy ty1 ty2) res_ty `thenTc_`
--- equivalent to \ x -> x op expr, or
+ returnTc (SectionL arg' op', lie, res_ty)
+
+-- Right sections, equivalent to \ x -> x op expr, or
-- \ x -> op x expr
-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_`
+tcExpr in_expr@(SectionR op expr)
+ = tcExpr op `thenTc` \ (op', lie1, op_ty) ->
+ tcExpr expr `thenTc` \ (expr',lie2, expr_ty) ->
+
+ newTyVarTy mkTypeKind `thenNF_Tc` \ ty1 ->
+ newTyVarTy mkTypeKind `thenNF_Tc` \ ty2 ->
+ tcAddErrCtxt (sectionRAppCtxt in_expr) $
+ unifyTauTy (mkFunTys [ty1, expr_ty] ty2) op_ty `thenTc_`
- returnTc (SectionR op' expr', plusLIE lie1 lie2, result_ty)
+ returnTc (SectionR op' expr', lie1 `plusLIE` lie2, mkFunTy ty1 ty2)
\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 ->
- 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"
+tcExpr (CCall lbl args may_gc is_asm ignored_fake_result_ty)
+ = -- Get the callable and returnable classes.
+ tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
+ tcLookupClassByKey cReturnableClassKey `thenNF_Tc` \ cReturnableClass ->
- new_arg_dict (arg, arg_ty) = newDict (CCallOrigin src_loc (_UNPK_ lbl) (Just arg))
- cCallableClass arg_ty
+ let
+ new_arg_dict (arg, arg_ty)
+ = newDicts (CCallOrigin (_UNPK_ lbl) (Just arg))
+ [(cCallableClass, arg_ty)] `thenNF_Tc` \ (arg_dicts, _) ->
+ returnNF_Tc arg_dicts -- Actually a singleton bag
- 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) ->
+ tcExprs args `thenTc` \ (args', args_lie, arg_tys) ->
-- 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 PrimIO
-- type constructor.
- newPolyTyVarTy `thenNF_Tc` \ result_ty ->
+ newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ result_ty ->
-- 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),
+ mapNF_Tc new_arg_dict (zipEqual "tcExpr:CCall" args arg_tys) `thenNF_Tc` \ ccarg_dicts_s ->
+ newDicts result_origin [(cReturnableClass, result_ty)] `thenNF_Tc` \ (ccres_dict, _) ->
+
+ returnTc (HsCon stDataCon [realWorldTy, 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,
mkPrimIoTy result_ty)
\end{code}
\begin{code}
-tcExpr e (SCC label expr)
- = tcExpr e expr `thenTc` \ (expr', lie, expr_ty) ->
+tcExpr (HsSCC label expr)
+ = tcExpr expr `thenTc` \ (expr', lie, expr_ty) ->
-- No unification. Give SCC the type of expr
- returnTc (SCC label expr', lie, expr_ty)
+ returnTc (HsSCC 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 (HsLet binds expr)
+ = tcBindsAndThen
+ HsLet -- The combiner
+ binds -- Bindings to check
+ (tcExpr 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 ->
+tcExpr in_expr@(HsCase expr matches src_loc)
+ = tcAddSrcLoc src_loc $
+ tcExpr expr `thenTc` \ (expr',lie1,expr_ty) ->
+ newTyVarTy mkTypeKind `thenNF_Tc` \ result_ty ->
- unifyTauTy (mkFunTy expr_ty result_ty) match_ty
- (CaseCtxt expr matches) `thenTc_`
+ tcAddErrCtxt (caseCtxt in_expr) $
+ tcMatchesCase (mkFunTy expr_ty result_ty) matches
+ `thenTc` \ (matches',lie2) ->
- returnTc (Case expr' matches', plusLIE lie1 lie2, result_ty)
+ returnTc (HsCase expr' matches' src_loc, plusLIE lie1 lie2, result_ty)
-tcExpr e (If pred b1 b2)
- = tcExpr e pred `thenTc` \ (pred',lie1,predTy) ->
+tcExpr (HsIf pred b1 b2 src_loc)
+ = tcAddSrcLoc src_loc $
+ tcExpr pred `thenTc` \ (pred',lie1,predTy) ->
- unifyTauTy predTy boolTy (PredCtxt pred) `thenTc_`
+ tcAddErrCtxt (predCtxt pred) (
+ unifyTauTy boolTy predTy
+ ) `thenTc_`
- tcExpr e b1 `thenTc` \ (b1',lie2,result_ty) ->
- tcExpr e b2 `thenTc` \ (b2',lie3,b2Ty) ->
+ tcExpr b1 `thenTc` \ (b1',lie2,result_ty) ->
+ tcExpr b2 `thenTc` \ (b2',lie3,b2Ty) ->
- unifyTauTy result_ty b2Ty (BranchCtxt b1 b2) `thenTc_`
+ tcAddErrCtxt (branchCtxt b1 b2) $
+ unifyTauTy result_ty b2Ty `thenTc_`
- returnTc (If pred' b1' b2', plusLIE lie1 (plusLIE lie2 lie3), result_ty)
+ returnTc (HsIf pred' b1' b2' src_loc, 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)
- where
- binders = collectQualBinders quals
+tcExpr (ListComp expr quals)
+ = tcListComp expr quals `thenTc` \ ((expr',quals'), lie, ty) ->
+ returnTc (ListComp expr' quals', lie, ty)
\end{code}
\begin{code}
-tcExpr e (ExplicitList [])
- = newPolyTyVarTy `thenNF_Tc` \ tyvar_ty ->
- returnTc (ExplicitListOut tyvar_ty [], nullLIE, mkListTy tyvar_ty)
+tcExpr expr@(HsDo stmts src_loc)
+ = tcDoStmts stmts src_loc
+\end{code}
+
+\begin{code}
+tcExpr (ExplicitList [])
+ = newTyVarTy mkBoxedTypeKind `thenNF_Tc` \ tyvar_ty ->
+ returnTc (ExplicitListOut tyvar_ty [], emptyLIE, mkListTy tyvar_ty)
-tcExpr e (ExplicitList exprs) -- Non-empty list
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) ->
- unifyTauTyList tys (ListCtxt exprs) `thenTc_`
+tcExpr in_expr@(ExplicitList exprs) -- Non-empty list
+ = tcExprs exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) ->
+ tcAddErrCtxt (listCtxt in_expr) $
+ unifyTauTyList tys `thenTc_`
returnTc (ExplicitListOut elt_ty exprs', lie, mkListTy elt_ty)
-tcExpr e (ExplicitTuple exprs)
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys) ->
+tcExpr (ExplicitTuple exprs)
+ = tcExprs exprs `thenTc` \ (exprs', lie, tys) ->
returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys)
-tcExpr e (ArithSeqIn seq@(From expr))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr `thenTc` \ (expr', lie, ty) ->
+tcExpr (RecordCon (HsVar con) rbinds)
+ = tcId con `thenNF_Tc` \ (con_expr, con_lie, con_tau) ->
let
- enum_from_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFrom")
+ (_, record_ty) = splitFunTy con_tau
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_id [ty] `thenNF_Tc` \ enum_from ->
+ -- Con is syntactically constrained to be a data constructor
+ ASSERT( maybeToBool (maybeAppDataTyCon record_ty ) )
+
+ tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+
+ -- Check that the record bindings match the constructor
+ tcLookupGlobalValue con `thenNF_Tc` \ con_id ->
+ checkTc (checkRecordFields rbinds con_id)
+ (badFieldsCon con rbinds) `thenTc_`
- returnTc (ArithSeqOut (Var (mkInstId enum_from)) (From expr'),
- plusLIE (unitLIE enum_from) lie,
- mkListTy ty)
+ returnTc (RecordCon con_expr rbinds', con_lie `plusLIE` rbinds_lie, record_ty)
-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) ->
+-- One small complication in RecordUpd is that 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.
- unifyTauTyList [ty1, ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+tcExpr (RecordUpd record_expr rbinds)
+ = ASSERT( not (null rbinds) )
+ tcAddErrCtxt recordUpdCtxt $
+
+ tcExpr record_expr `thenTc` \ (record_expr', record_lie, record_ty) ->
+ tcRecordBinds record_ty rbinds `thenTc` \ (rbinds', rbinds_lie) ->
+
+ -- Check that the field names are plausible
+ zonkTcType record_ty `thenNF_Tc` \ record_ty' ->
let
- enum_from_then_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThen")
+ (tycon, inst_tys, data_cons) = --trace "TcExpr.getAppDataTyCon" $
+ getAppDataTyCon record_ty'
+ -- The record binds are non-empty (syntax); so at least one field
+ -- label will have been unified with record_ty by tcRecordBinds;
+ -- field labels must be of data type; hencd the getAppDataTyCon must succeed.
+ (tyvars, theta, _, _) = dataConSig (head data_cons)
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_id [ty1] `thenNF_Tc` \ enum_from_then ->
+ tcInstTheta (zipEqual "tcExpr:RecordUpd" tyvars inst_tys) theta `thenNF_Tc` \ theta' ->
+ newDicts RecordUpdOrigin theta' `thenNF_Tc` \ (con_lie, dicts) ->
+ checkTc (any (checkRecordFields rbinds) data_cons)
+ (badFieldsUpd rbinds) `thenTc_`
+
+ returnTc (RecordUpdOut record_expr' dicts rbinds',
+ con_lie `plusLIE` record_lie `plusLIE` rbinds_lie,
+ record_ty)
+
+tcExpr (ArithSeqIn seq@(From expr))
+ = tcExpr expr `thenTc` \ (expr', lie1, ty) ->
+
+ tcLookupGlobalValueByKey enumFromClassOpKey `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq)
+ (RealId sel_id) [ty] `thenNF_Tc` \ (lie2, enum_from_id) ->
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then))
+ returnTc (ArithSeqOut (HsVar enum_from_id) (From expr'),
+ lie1 `plusLIE` lie2,
+ mkListTy ty)
+
+tcExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2))
+ = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) ->
+ tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) ->
+
+ tcAddErrCtxt (arithSeqCtxt in_expr) $
+ unifyTauTyList [ty1, ty2] `thenTc_`
+
+ tcLookupGlobalValueByKey enumFromThenClassOpKey `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq)
+ (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_then_id) ->
+
+ returnTc (ArithSeqOut (HsVar enum_from_then_id)
(FromThen expr1' expr2'),
- (unitLIE enum_from_then) `plusLIE` lie1 `plusLIE` lie2,
+ lie1 `plusLIE` lie2 `plusLIE` lie3,
mkListTy ty1)
-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) ->
+tcExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2))
+ = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) ->
+ tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) ->
- unifyTauTyList [ty1,ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
- let
- enum_from_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromTo")
- 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,
+ tcAddErrCtxt (arithSeqCtxt in_expr) $
+ unifyTauTyList [ty1,ty2] `thenTc_`
+
+ tcLookupGlobalValueByKey enumFromToClassOpKey `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq)
+ (RealId sel_id) [ty1] `thenNF_Tc` \ (lie3, enum_from_to_id) ->
+
+ returnTc (ArithSeqOut (HsVar enum_from_to_id)
+ (FromTo expr1' expr2'),
+ lie1 `plusLIE` lie2 `plusLIE` lie3,
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) ->
+tcExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3))
+ = tcExpr expr1 `thenTc` \ (expr1',lie1,ty1) ->
+ tcExpr expr2 `thenTc` \ (expr2',lie2,ty2) ->
+ tcExpr expr3 `thenTc` \ (expr3',lie3,ty3) ->
- unifyTauTyList [ty1,ty2,ty3] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
- let
- enum_from_then_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThenTo")
- in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_to_id [ty1] `thenNF_Tc` \ enum_from_then_to ->
+ tcAddErrCtxt (arithSeqCtxt in_expr) $
+ unifyTauTyList [ty1,ty2,ty3] `thenTc_`
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then_to))
+ tcLookupGlobalValueByKey enumFromThenToClassOpKey `thenNF_Tc` \ sel_id ->
+ newMethod (ArithSeqOrigin seq)
+ (RealId sel_id) [ty1] `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,
+ mkListTy ty1)
\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 ->
+tcExpr in_expr@(ExprWithTySig expr poly_ty)
+ = tcExpr expr `thenTc` \ (texpr, lie, tau_ty) ->
+ tcPolyType 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_`
+ tcSetErrCtxt (exprSigCtxt in_expr) $
+ tcInstSigType sigma_sig `thenNF_Tc` \ sigma_sig' ->
+ let
+ (sig_tyvars', sig_theta', sig_tau') = splitSigmaTy sigma_sig'
+ in
+ unifyTauTy sig_tau' tau_ty `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' ->
+ checkSigTyVars sig_tyvars' sig_tau' `thenTc_`
-- Check overloading constraints
+ newDicts SignatureOrigin sig_theta' `thenNF_Tc` \ (sig_dicts, _) ->
tcSimplifyAndCheck
- False {- Not top level -}
- env_tyvars sig_tyvars'
- sig_dicts (unMkLIE lie)
- (ExprSigCtxt expr sigma_sig) `thenTc_`
+ (mkTyVarSet sig_tyvars')
+ sig_dicts lie `thenTc_`
-- If everything is ok, return the stuff unchanged, except for
-- the effect of any substutions etc. We simply discard the
%************************************************************************
%* *
-\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}
+tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
+ -> TcM s (TcExpr s, [TcExpr s], -- Translated fun and args
+ LIE s,
+ TcType s) -- Type of the application
-\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 fun args
+ = -- First type-check the function
+ -- In the HsVar case we go straight to tcId to avoid hitting the
+ -- rank-2 check, which we check later here anyway
+ (case fun of
+ HsVar name -> tcId name `thenNF_Tc` \ stuff -> returnTc stuff
+ other -> tcExpr fun
+ ) `thenTc` \ (fun', lie_fun, fun_ty) ->
-\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_help fun 1 fun_ty args `thenTc` \ (args', lie_args, res_ty) ->
-Constraints enforced by the Static semantics for Explicit Pods
-exp = << $exp_1$ ... $exp_n$>> (where $n >= 0$)
+ -- 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 res_ty)
+ (lurkingRank2Err fun fun_ty) `thenTc_`
-\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}
+ returnTc (fun', args', lie_fun `plusLIE` lie_args, res_ty)
+
+
+tcApp_help :: RenamedHsExpr -> Int -- Function and arg position, used in error message(s)
+ -> TcType s -- The type of the function
+ -> [RenamedHsExpr] -- Arguments
+ -> TcM s ([TcExpr s], -- Typechecked args
+ LIE s,
+ TcType s) -- Result type of the application
+
+tcApp_help orig_fun arg_no fun_ty []
+ = returnTc ([], emptyLIE, fun_ty)
+
+tcApp_help orig_fun arg_no fun_ty all_args@(arg:args)
+ = -- Expect the function to have type A->B
+ tcAddErrCtxt (tooManyArgsCtxt orig_fun) (
+ unifyFunTy fun_ty
+ ) `thenTc` \ (expected_arg_ty, result_ty) ->
+
+ -- Type check the argument
+ tcAddErrCtxt (funAppCtxt orig_fun arg_no arg) (
+ tcArg expected_arg_ty arg
+ ) `thenTc` \ (arg', lie_arg) ->
+
+ -- Do the other args
+ tcApp_help orig_fun (arg_no+1) result_ty args `thenTc` \ (args', lie_args, res_ty) ->
+
+ -- Done
+ returnTc (arg':args', lie_arg `plusLIE` lie_args, res_ty)
-\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 -}
\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 :: TcType s -- Expected arg type
+ -> RenamedHsExpr -- Actual argument
+ -> TcM s (TcExpr s, LIE s) -- Resulting argument and LIE
+
+tcArg expected_arg_ty arg
+ | not (maybeToBool (getForAllTy_maybe expected_arg_ty))
+ = -- The ordinary, non-rank-2 polymorphic case
+ tcExpr arg `thenTc` \ (arg', lie_arg, actual_arg_ty) ->
+ unifyTauTy expected_arg_ty actual_arg_ty `thenTc_`
+ returnTc (arg', lie_arg)
+
+ | otherwise
+ = -- Ha! The argument type of the function is a for-all type,
+ -- An example of rank-2 polymorphism.
+
+ -- No need to instantiate the argument type... it's must be the result
+ -- of instantiating a function involving rank-2 polymorphism, so there
+ -- isn't any danger of using the same tyvars twice
+ -- The argument type shouldn't be overloaded type (hence ASSERT)
+
+ -- To ensure that the forall'd type variables don't get unified with each
+ -- other or any other types, we make fresh *signature* type variables
+ -- and unify them with the tyvars.
+ tcInstSigTcType expected_arg_ty `thenNF_Tc` \ (sig_tyvars, sig_rho) ->
+ let
+ (sig_theta, sig_tau) = splitRhoTy sig_rho
+ in
+ ASSERT( null sig_theta ) -- And expected_tyvars are all DontBind things
+
+ -- Type-check the arg and unify with expected type
+ tcExpr arg `thenTc` \ (arg', lie_arg, actual_arg_ty) ->
+ unifyTauTy sig_tau actual_arg_ty `thenTc_`
+
+ -- 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.
+
+ tcAddErrCtxt (rank2ArgCtxt arg expected_arg_ty) (
+ tcExtendGlobalTyVars (tyVarsOfType expected_arg_ty) (
+ checkSigTyVars sig_tyvars sig_tau
+ ) `thenTc_`
+
+ -- Check that there's no overloading involved
+ -- Even if there isn't, there may be some Insts which mention the expected_tyvars,
+ -- but which, on simplification, don't actually need a dictionary involving
+ -- the tyvar. So we have to do a proper simplification right here.
+ tcSimplifyRank2 (mkTyVarSet sig_tyvars)
+ lie_arg `thenTc` \ (free_insts, inst_binds) ->
+
+ -- 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.
+ returnTc (TyLam sig_tyvars (HsLet (mk_binds inst_binds) arg'), free_insts)
+ )
+ where
+
+ mk_binds [] = EmptyBinds
+ mk_binds ((inst,rhs):inst_binds)
+ = (SingleBind (NonRecBind (VarMonoBind inst rhs))) `ThenBinds`
+ mk_binds inst_binds
\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.
+\begin{code}
+tcId :: RnName -> NF_TcM s (TcExpr s, LIE s, TcType s)
+
+tcId name
+ = -- Look up the Id and instantiate its type
+ tcLookupLocalValue name `thenNF_Tc` \ maybe_local ->
+
+ case maybe_local of
+ Just tc_id -> instantiate_it (TcId tc_id) (idType tc_id)
+
+ Nothing -> tcLookupGlobalValue name `thenNF_Tc` \ id ->
+ tcInstType [] (idType id) `thenNF_Tc` \ inst_ty ->
+ let
+ (tyvars, rho) = splitForAllTy inst_ty
+ in
+ instantiate_it2 (RealId id) tyvars rho
+
+ 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 tc_id_occ ty
+ = tcInstTcType ty `thenNF_Tc` \ (tyvars, rho) ->
+ instantiate_it2 tc_id_occ tyvars rho
+
+ instantiate_it2 tc_id_occ tyvars rho
+ | null theta -- Is it overloaded?
+ = returnNF_Tc (mkHsTyApp (HsVar tc_id_occ) arg_tys, emptyLIE, tau)
+
+ | otherwise -- Yes, it's overloaded
+ = newMethodWithGivenTy (OccurrenceOf tc_id_occ)
+ tc_id_occ arg_tys rho `thenNF_Tc` \ (lie1, meth_id) ->
+ instantiate_it meth_id tau `thenNF_Tc` \ (expr, lie2, final_tau) ->
+ returnNF_Tc (expr, lie1 `plusLIE` lie2, final_tau)
+
+ where
+ (theta, tau) = splitRhoTy rho
+ arg_tys = mkTyVarTys tyvars
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{@tcQuals@ typechecks list-comprehension qualifiers}
+%* *
+%************************************************************************
\begin{code}
-tcExprs :: E -> [RenamedExpr] -> TcM ([TypecheckedExpr],LIE,[TauType])
+tcListComp expr []
+ = tcExpr expr `thenTc` \ (expr', lie, ty) ->
+ returnTc ((expr',[]), lie, mkListTy ty)
+
+tcListComp expr (qual@(FilterQual filter) : quals)
+ = tcAddErrCtxt (qualCtxt qual) (
+ tcExpr filter `thenTc` \ (filter', filter_lie, filter_ty) ->
+ unifyTauTy boolTy filter_ty `thenTc_`
+ returnTc (FilterQual filter', filter_lie)
+ ) `thenTc` \ (qual', qual_lie) ->
+
+ tcListComp expr quals `thenTc` \ ((expr',quals'), rest_lie, res_ty) ->
+
+ returnTc ((expr', qual' : quals'),
+ qual_lie `plusLIE` rest_lie,
+ res_ty)
+
+tcListComp expr (qual@(GeneratorQual pat rhs) : quals)
+ = newMonoIds binder_names mkBoxedTypeKind (\ ids ->
+
+ tcAddErrCtxt (qualCtxt qual) (
+ tcPat pat `thenTc` \ (pat', lie_pat, pat_ty) ->
+ tcExpr rhs `thenTc` \ (rhs', lie_rhs, rhs_ty) ->
+ -- NB: the environment has been extended with the new binders
+ -- which the rhs can't "see", but the renamer should have made
+ -- sure that everything is distinct by now, so there's no problem.
+ -- Putting the tcExpr before the newMonoIds messes up the nesting
+ -- of error contexts, so I didn't bother
+
+ unifyTauTy (mkListTy pat_ty) rhs_ty `thenTc_`
+ returnTc (GeneratorQual pat' rhs',
+ lie_pat `plusLIE` lie_rhs)
+ ) `thenTc` \ (qual', lie_qual) ->
+
+ tcListComp expr quals `thenTc` \ ((expr',quals'), lie_rest, res_ty) ->
+
+ returnTc ((expr', qual' : quals'),
+ lie_qual `plusLIE` lie_rest,
+ res_ty)
+ )
+ where
+ binder_names = collectPatBinders pat
-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)
+tcListComp expr (LetQual binds : quals)
+ = tcBindsAndThen -- No error context, but a binding group is
+ combine -- rather a large thing for an error context anyway
+ binds
+ (tcListComp expr quals)
+ where
+ combine binds' (expr',quals') = (expr', LetQual binds' : quals')
\end{code}
%************************************************************************
%* *
-\subsection{@tcApp@ typchecks an application}
+\subsection{@tcDoStmts@ typechecks a {\em list} of do statements}
%* *
%************************************************************************
\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' ->
- let
- err_ctxt = FunAppCtxt orig_fun maybe_fun_id arg arg_ty' actual_arg_ty' arg_no
- in
- matchArgTy e arg_ty' arg' lie_arg actual_arg_ty' err_ctxt
- `thenTc` \ (arg'', lie_arg') ->
+tcDoStmts stmts src_loc
+ = -- get the Monad and MonadZero classes
+ -- create type consisting of a fresh monad tyvar
+ tcAddSrcLoc src_loc $
+ newTyVarTy (mkArrowKind mkBoxedTypeKind mkBoxedTypeKind) `thenNF_Tc` \ m ->
+
+
+ -- Build the then and zero methods in case we need them
+ tcLookupGlobalValueByKey thenMClassOpKey `thenNF_Tc` \ then_sel_id ->
+ tcLookupGlobalValueByKey zeroClassOpKey `thenNF_Tc` \ zero_sel_id ->
+ newMethod DoOrigin
+ (RealId then_sel_id) [m] `thenNF_Tc` \ (m_lie, then_id) ->
+ newMethod DoOrigin
+ (RealId zero_sel_id) [m] `thenNF_Tc` \ (mz_lie, zero_id) ->
+
+ let
+ get_m_arg ty
+ = newTyVarTy mkTypeKind `thenNF_Tc` \ arg_ty ->
+ unifyTauTy (mkAppTy m arg_ty) ty `thenTc_`
+ returnTc arg_ty
+
+ go [stmt@(ExprStmt exp src_loc)]
+ = tcAddSrcLoc src_loc $
+ tcSetErrCtxt (stmtCtxt stmt) $
+ tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) ->
+ returnTc ([ExprStmt exp' src_loc], exp_lie, exp_ty)
+
+ go (stmt@(ExprStmt exp src_loc) : stmts)
+ = tcAddSrcLoc src_loc (
+ tcSetErrCtxt (stmtCtxt stmt) (
+ tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) ->
+ get_m_arg exp_ty `thenTc` \ a ->
+ returnTc (a, exp', exp_lie)
+ )) `thenTc` \ (a, exp', exp_lie) ->
+ go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) ->
+ get_m_arg stmts_ty `thenTc` \ b ->
+ returnTc (ExprStmtOut exp' src_loc a b : stmts',
+ exp_lie `plusLIE` stmts_lie `plusLIE` m_lie,
+ stmts_ty)
+
+ go (stmt@(BindStmt pat exp src_loc) : stmts)
+ = newMonoIds (collectPatBinders pat) mkBoxedTypeKind $ \ _ ->
+ tcAddSrcLoc src_loc (
+ tcSetErrCtxt (stmtCtxt stmt) (
+ tcPat pat `thenTc` \ (pat', pat_lie, pat_ty) ->
+ tcExpr exp `thenTc` \ (exp', exp_lie, exp_ty) ->
+ -- See comments with tcListComp on GeneratorQual
+
+ get_m_arg exp_ty `thenTc` \ a ->
+ unifyTauTy pat_ty a `thenTc_`
+ returnTc (a, pat', exp', pat_lie `plusLIE` exp_lie)
+ )) `thenTc` \ (a, pat', exp', stmt_lie) ->
+ go stmts `thenTc` \ (stmts', stmts_lie, stmts_ty) ->
+ get_m_arg stmts_ty `thenTc` \ b ->
+ returnTc (BindStmtOut pat' exp' src_loc a b : stmts',
+ stmt_lie `plusLIE` stmts_lie `plusLIE` m_lie `plusLIE`
+ (if failureFreePat pat' then emptyLIE else mz_lie),
+ stmts_ty)
+
+ go (LetStmt binds : stmts)
+ = tcBindsAndThen -- No error context, but a binding group is
+ combine -- rather a large thing for an error context anyway
+ binds
+ (go stmts)
+ where
+ combine binds' stmts' = LetStmt binds' : stmts'
+ in
- unify_args (arg_no+1) (App fun arg'') (lie `plusLIE` lie_arg') args arg_tys fun_res_ty
+ go stmts `thenTc` \ (stmts', final_lie, final_ty) ->
+ returnTc (HsDoOut stmts' then_id zero_id src_loc,
+ final_lie,
+ final_ty)
+\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.
+
+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}
+tcRecordBinds
+ :: TcType s -- Expected type of whole record
+ -> RenamedRecordBinds
+ -> TcM s (TcRecordBinds s, LIE s)
+
+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 ->
+ tcInstId sel_id `thenNF_Tc` \ (_, _, tau) ->
- 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.
+ -- Record selectors all have type
+ -- forall a1..an. T a1 .. an -> tau
+ ASSERT( maybeToBool (getFunTy_maybe tau) )
let
- result_ty = glueTyArgs arg_tys fun_res_ty
+ -- Selector must have type RecordType -> FieldType
+ Just (record_ty, field_ty) = getFunTy_maybe tau
in
- checkTc (not (isTauTy result_ty))
- (error "ERROR: 2 rank failure (NEED ERROR MSG [ToDo])") `thenTc_`
- returnTc (fun, lie, result_ty)
+ unifyTauTy expected_record_ty record_ty `thenTc_`
+ tcArg field_ty rhs `thenTc` \ (rhs', lie) ->
+ returnTc ((RealId sel_id, rhs', pun_flag), lie)
- -- 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
+checkRecordFields :: RenamedRecordBinds -> Id -> Bool -- True iff all the fields in
+ -- RecordBinds are field of the
+ -- specified constructor
+checkRecordFields rbinds data_con
+ = all ok rbinds
+ where
+ data_con_fields = dataConFieldLabels data_con
+ ok (field_name, _, _) = any (match (getName field_name)) data_con_fields
- unify_fun :: Int -- Current argument number
- -> TypecheckedExpr -- Current rebuilt expression
- -> LIE -- Corresponding LIE
- -> [RenamedExpr] -- Remaining args
- -> TauType -- Remaining function type
- -> TcM (TypecheckedExpr, LIE, UniType)
-
- 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' ->
+ match field_name field_label = field_name == fieldLabelName field_label
+\end{code}
- -- Now see whether it has any arguments
- case (splitTyArgs fun_ty') of
+%************************************************************************
+%* *
+\subsection{@tcExprs@ typechecks a {\em list} of expressions}
+%* *
+%************************************************************************
- ([], _) -> -- Function has no arguments left
+\begin{code}
+tcExprs :: [RenamedHsExpr] -> TcM s ([TcExpr s], LIE s, [TcType s])
- newOpenTyVarTy `thenNF_Tc` \ result_ty ->
- tcExprs e args `thenTc` \ (args', lie_args, arg_tys) ->
+tcExprs [] = returnTc ([], emptyLIE, [])
+tcExprs (expr:exprs)
+ = tcExpr expr `thenTc` \ (expr', lie1, ty) ->
+ tcExprs exprs `thenTc` \ (exprs', lie2, tys) ->
+ returnTc (expr':exprs', lie1 `plusLIE` lie2, ty:tys)
+\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 -> Pretty -> Pretty
+pp_nest_hang label stuff = ppNest 2 (ppHang (ppStr label) 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
+arithSeqCtxt expr sty
+ = ppHang (ppStr "In an arithmetic sequence:") 4 (ppr sty expr)
-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.
+branchCtxt b1 b2 sty
+ = ppSep [ppStr "In the branches of a conditional:",
+ pp_nest_hang "`then' branch:" (ppr sty b1),
+ pp_nest_hang "`else' branch:" (ppr sty b2)]
- -- This applyTcSubstToTy is just to improve the error message..
+caseCtxt expr sty
+ = ppHang (ppStr "In a case expression:") 4 (ppr sty expr)
- applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' ->
+exprSigCtxt expr sty
+ = ppHang (ppStr "In an expression with a type signature:")
+ 4 (ppr sty expr)
- -- Instantiate the argument type
- -- ToDo: give this a real origin
- specTy UnknownOrigin expected_arg_ty `thenNF_Tc` \ (arg_tyvars, arg_lie, arg_tau) ->
+listCtxt expr sty
+ = ppHang (ppStr "In a list expression:") 4 (ppr sty expr)
- if not (null arg_lie) then
- -- Paranoia check
- panic "Non-null overloading in tcApp"
- else
- -- Assert: arg_lie = []
+predCtxt expr sty
+ = ppHang (ppStr "In a predicate expression:") 4 (ppr sty expr)
- unifyTauTy arg_tau actual_arg_ty' err_ctxt `thenTc_`
+sectionRAppCtxt expr sty
+ = ppHang (ppStr "In a right section:") 4 (ppr sty 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' ->
+sectionLAppCtxt expr sty
+ = ppHang (ppStr "In a left section:") 4 (ppr sty expr)
- tcSimplifyRank2 arg_tyvars' insts' rank2_err_ctxt `thenTc` \ (free_insts, inst_binds) ->
+funAppCtxt fun arg_no arg sty
+ = ppHang (ppCat [ ppStr "In the", speakNth arg_no, ppStr "argument of", ppr sty fun])
+ 4 (ppCat [ppStr "namely", ppr sty arg])
- -- 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)
+qualCtxt qual sty
+ = ppHang (ppStr "In a list-comprehension qualifer:")
+ 4 (ppr sty qual)
- | otherwise
- = -- The ordinary, non-rank-2 polymorphic case
- unifyTauTy expected_arg_ty actual_arg_ty err_ctxt `thenTc_`
- returnTc (arg_expr, actual_arg_lie)
+stmtCtxt stmt sty
+ = ppHang (ppStr "In a do statement:")
+ 4 (ppr sty stmt)
- where
- rank2_err_ctxt = Rank2ArgCtxt arg_expr expected_arg_ty
+tooManyArgsCtxt f sty
+ = ppHang (ppStr "Too many arguments in an application of the function")
+ 4 (ppr sty f)
- mk_binds [] = EmptyBinds
- mk_binds ((inst,rhs):inst_binds) = (SingleBind (NonRecBind (VarMonoBind (mkInstId inst) rhs)))
- `ThenBinds`
- mk_binds inst_binds
-\end{code}
+lurkingRank2Err fun fun_ty sty
+ = ppHang (ppCat [ppStr "Illegal use of", ppr sty fun])
+ 4 (ppAboves [ppStr "It is applied to too few arguments,",
+ ppStr "so that the result type has for-alls in it"])
-This version only does not check for 2nd order if it is applied.
+rank2ArgCtxt arg expected_arg_ty sty
+ = ppHang (ppStr "In a polymorphic function argument:")
+ 4 (ppSep [ppBeside (ppr sty arg) (ppStr " ::"),
+ ppr sty expected_arg_ty])
-\begin{code}
-tcExpr' :: E -> RenamedExpr -> Int -> TcM (TypecheckedExpr,LIE,UniType)
+badFieldsUpd rbinds sty
+ = ppHang (ppStr "No constructor has all these fields:")
+ 4 (interpp'SP sty fields)
+ where
+ fields = [field | (field, _, _) <- rbinds]
-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
+recordUpdCtxt sty = ppStr "In a record update construct"
+
+badFieldsCon con rbinds sty
+ = ppHang (ppBesides [ppStr "Inconsistent constructor:", ppr sty con])
+ 4 (ppBesides [ppStr "and fields:", interpp'SP sty fields])
+ where
+ fields = [field | (field, _, _) <- rbinds]
\end{code}
projects / ghc-hetmet.git / blobdiff