X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcPat.lhs;h=4fe704a84abca4f32842bce3370be85f5cac1312;hb=90dc9026b091be5cca5da4c6cbd3713ecc493361;hp=a4f3a82521385903f2bf4e57a42c9b83d1caf658;hpb=e6d057711f4d6d6ff6342c39fa2b9e44d25447f1;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcPat.lhs b/compiler/typecheck/TcPat.lhs index a4f3a82..4fe704a 100644 --- a/compiler/typecheck/TcPat.lhs +++ b/compiler/typecheck/TcPat.lhs @@ -1,7 +1,9 @@ % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % -\section[TcPat]{Typechecking patterns} + +TcPat: Typechecking patterns \begin{code} module TcPat ( tcLetPat, tcLamPat, tcLamPats, tcOverloadedLit, @@ -10,57 +12,34 @@ module TcPat ( tcLetPat, tcLamPat, tcLamPats, tcOverloadedLit, #include "HsVersions.h" import {-# SOURCE #-} TcExpr( tcSyntaxOp ) -import HsSyn ( Pat(..), LPat, HsConDetails(..), HsLit(..), - HsOverLit(..), HsExpr(..), HsWrapper(..), - mkCoPat, - LHsBinds, emptyLHsBinds, isEmptyLHsBinds, - collectPatsBinders, nlHsLit ) -import TcHsSyn ( TcId, hsLitType ) + +import HsSyn +import TcHsSyn import TcRnMonad -import Inst ( InstOrigin(..), shortCutFracLit, shortCutIntLit, - newDictBndrs, instToId, instStupidTheta, isHsVar - ) -import Id ( Id, idType, mkLocalId ) -import Var ( CoVar, tyVarKind ) -import CoreFVs ( idFreeTyVars ) -import Name ( Name, mkSystemVarName ) -import TcSimplify ( tcSimplifyCheck, bindInstsOfLocalFuns ) -import TcEnv ( newLocalName, tcExtendIdEnv1, tcExtendTyVarEnv2, - tcLookupClass, tcLookupDataCon, refineEnvironment, - tcLookupField, tcMetaTy ) -import TcMType ( newFlexiTyVarTy, arityErr, tcInstSkolTyVars, - newCoVars, zonkTcType, tcInstTyVars, newBoxyTyVar ) -import TcType ( TcType, TcTyVar, TcSigmaType, TcRhoType, BoxyType, - SkolemInfo(PatSkol), - BoxySigmaType, BoxyRhoType, argTypeKind, typeKind, - pprSkolTvBinding, isRigidTy, tcTyVarsOfTypes, - zipTopTvSubst, isSubArgTypeKind, isUnboxedTupleType, - mkTyVarTys, mkClassPred, isOverloadedTy, substEqSpec, - mkFunTy, mkFunTys, tidyOpenType, tidyOpenTypes, - mkTyVarTy ) -import VarSet ( elemVarSet ) -import {- Kind parts of -} - Type ( liftedTypeKind ) -import TcUnify ( boxySplitTyConApp, boxySplitListTy, unBox, - zapToMonotype, boxyUnify, boxyUnifyList, - checkSigTyVarsWrt, unifyType ) -import TcHsType ( UserTypeCtxt(..), tcPatSig ) -import TysWiredIn ( boolTy, parrTyCon, tupleTyCon ) -import TcGadt ( Refinement, emptyRefinement, gadtRefine, refineType ) -import Type ( Type, mkTyConApp, substTys, substTheta ) -import StaticFlags ( opt_IrrefutableTuples ) -import TyCon ( TyCon, FieldLabel, tyConFamInst_maybe, - tyConFamilyCoercion_maybe, tyConTyVars ) -import DataCon ( DataCon, dataConTyCon, dataConFullSig, dataConName, - dataConFieldLabels, dataConSourceArity, - dataConStupidTheta, dataConUnivTyVars ) -import PrelNames ( integralClassName, fromIntegerName, integerTyConName, - fromRationalName, rationalTyConName ) -import BasicTypes ( isBoxed ) -import SrcLoc ( Located(..), SrcSpan, noLoc ) -import ErrUtils ( Message ) -import Util ( zipEqual ) -import Maybes ( MaybeErr(..) ) +import Inst +import Id +import Var +import CoreFVs +import Name +import TcSimplify +import TcEnv +import TcMType +import TcType +import VarSet +import TcUnify +import TcHsType +import TysWiredIn +import TcGadt +import Type +import StaticFlags +import TyCon +import DataCon +import PrelNames +import BasicTypes hiding (SuccessFlag(..)) +import SrcLoc +import ErrUtils +import Util +import Maybes import Outputable import FastString \end{code} @@ -153,7 +132,7 @@ tcCheckExistentialPat pats [] pat_tys body_ty = return () -- Short cut for case when there are no existentials tcCheckExistentialPat pats ex_tvs pat_tys body_ty - = addErrCtxtM (sigPatCtxt (collectPatsBinders pats) ex_tvs pat_tys body_ty) $ + = addErrCtxtM (sigPatCtxt pats ex_tvs pat_tys body_ty) $ checkSigTyVarsWrt (tcTyVarsOfTypes (body_ty:pat_tys)) ex_tvs data PatState = PS { @@ -190,18 +169,18 @@ tcPatBndr (PS { pat_ctxt = LamPat }) bndr_name pat_ty -- f t = case t of { MkT g -> ... } -- Here, the 'g' must get type (forall a. a->a) from the -- MkT context - ; return (mkLocalId bndr_name pat_ty') } + ; return (Id.mkLocalId bndr_name pat_ty') } tcPatBndr (PS { pat_ctxt = LetPat lookup_sig }) bndr_name pat_ty | Just mono_ty <- lookup_sig bndr_name = do { mono_name <- newLocalName bndr_name ; boxyUnify mono_ty pat_ty - ; return (mkLocalId mono_name mono_ty) } + ; return (Id.mkLocalId mono_name mono_ty) } | otherwise = do { pat_ty' <- unBoxPatBndrType pat_ty bndr_name ; mono_name <- newLocalName bndr_name - ; return (mkLocalId mono_name pat_ty') } + ; return (Id.mkLocalId mono_name pat_ty') } ------------------- @@ -300,7 +279,9 @@ tc_lpat :: LPat Name tc_lpat (L span pat) pat_ty pstate thing_inside = setSrcSpan span $ maybeAddErrCtxt (patCtxt pat) $ - do { let (coercion, pat_ty') = refineType (pat_reft pstate) pat_ty + do { let mb_reft = refineType (pat_reft pstate) pat_ty + pat_ty' = case mb_reft of { Just (_, ty') -> ty'; Nothing -> pat_ty } + -- Make sure the result type reflects the current refinement -- We must do this here, so that it correctly ``sees'' all -- the refinements to the left. Example: @@ -310,7 +291,10 @@ tc_lpat (L span pat) pat_ty pstate thing_inside -- pattern had better see it. ; (pat', tvs, res) <- tc_pat pstate pat pat_ty' thing_inside - ; return (mkCoPat coercion (L span pat') pat_ty, tvs, res) } + ; let final_pat = case mb_reft of + Nothing -> pat' + Just (co,_) -> CoPat (WpCo co) pat' pat_ty + ; return (L span final_pat, tvs, res) } -------------------- tc_pat :: PatState @@ -348,11 +332,26 @@ tc_pat pstate (BangPat pat) pat_ty thing_inside -- -- Nor should a lazy pattern bind any existential type variables -- because they won't be in scope when we do the desugaring +-- +-- Note [Hopping the LIE in lazy patterns] +-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +-- In a lazy pattern, we must *not* discharge constraints from the RHS +-- from dictionaries bound in the pattern. E.g. +-- f ~(C x) = 3 +-- We can't discharge the Num constraint from dictionaries bound by +-- the pattern C! +-- +-- So we have to make the constraints from thing_inside "hop around" +-- the pattern. Hence the getLLE and extendLIEs later. + tc_pat pstate lpat@(LazyPat pat) pat_ty thing_inside - = do { (pat', pat_tvs, res) <- tc_lpat pat pat_ty pstate $ \ _ -> - thing_inside pstate - -- Ignore refined pstate', - -- revert to pstate + = do { (pat', pat_tvs, (res,lie)) + <- tc_lpat pat pat_ty pstate $ \ _ -> + getLIE (thing_inside pstate) + -- Ignore refined pstate', revert to pstate + ; extendLIEs lie + -- getLIE/extendLIEs: see Note [Hopping the LIE in lazy patterns] + -- Check no existentials ; if (null pat_tvs) then return () else lazyPatErr lpat pat_tvs @@ -547,16 +546,16 @@ tcConPat :: PatState -> SrcSpan -> DataCon -> TyCon -> HsConDetails Name (LPat Name) -> (PatState -> TcM a) -> TcM (Pat TcId, [TcTyVar], a) tcConPat pstate con_span data_con tycon pat_ty arg_pats thing_inside - = do { span <- getSrcSpanM -- Span for the whole pattern - ; let (univ_tvs, ex_tvs, eq_spec, theta, arg_tys) = dataConFullSig data_con - skol_info = PatSkol data_con span + = do { let (univ_tvs, ex_tvs, eq_spec, theta, arg_tys) = dataConFullSig data_con + skol_info = PatSkol data_con origin = SigOrigin skol_info -- Instantiate the constructor type variables [a->ty] ; ctxt_res_tys <- boxySplitTyConAppWithFamily tycon pat_ty - ; ex_tvs' <- tcInstSkolTyVars skol_info ex_tvs + ; ex_tvs' <- tcInstSkolTyVars skol_info ex_tvs -- Get location from monad, + -- not from ex_tvs ; let tenv = zipTopTvSubst (univ_tvs ++ ex_tvs) - (ctxt_res_tys ++ mkTyVarTys ex_tvs') + (ctxt_res_tys ++ mkTyVarTys ex_tvs') eq_spec' = substEqSpec tenv eq_spec theta' = substTheta tenv theta arg_tys' = substTys tenv arg_tys @@ -569,7 +568,8 @@ tcConPat pstate con_span data_con tycon pat_ty arg_pats thing_inside ; loc <- getInstLoc origin ; dicts <- newDictBndrs loc theta' - ; dict_binds <- tcSimplifyCheck doc ex_tvs' dicts lie_req + ; dict_binds <- tcSimplifyCheckPat loc co_vars (pat_reft pstate') + ex_tvs' dicts lie_req ; addDataConStupidTheta data_con ctxt_res_tys @@ -583,8 +583,6 @@ tcConPat pstate con_span data_con tycon pat_ty arg_pats thing_inside ex_tvs' ++ inner_tvs, res) } where - doc = ptext SLIT("existential context for") <+> quotes (ppr data_con) - -- Split against the family tycon if the pattern constructor belongs to a -- representation tycon. -- @@ -654,11 +652,12 @@ tcConArgs data_con arg_tys (RecCon rpats) pstate thing_inside = do { (rpats', tvs, res) <- tcMultiple tc_field rpats pstate thing_inside ; return (RecCon rpats', tvs, res) } where - tc_field :: Checker (Located Name, LPat Name) (Located TcId, LPat TcId) - tc_field (field_lbl, pat) pstate thing_inside + -- doc comments are typechecked to Nothing here + tc_field :: Checker (HsRecField FieldLabel (LPat Name)) (HsRecField TcId (LPat TcId)) + tc_field (HsRecField field_lbl pat _) pstate thing_inside = do { (sel_id, pat_ty) <- wrapLocFstM find_field_ty field_lbl ; (pat', tvs, res) <- tcConArg (pat, pat_ty) pstate thing_inside - ; return ((sel_id, pat'), tvs, res) } + ; return (mkRecField sel_id pat', tvs, res) } find_field_ty :: FieldLabel -> TcM (Id, TcType) find_field_ty field_lbl @@ -814,13 +813,27 @@ tcOverloadedLit orig lit@(HsFractional r fr) res_ty = do { expr <- newLitInst orig lit res_ty ; return (HsFractional r expr) } +tcOverloadedLit orig lit@(HsIsString s fr) res_ty + | not (fr `isHsVar` fromStringName) -- c.f. HsIntegral case + = do { str_ty <- tcMetaTy stringTyConName + ; fr' <- tcSyntaxOp orig fr (mkFunTy str_ty res_ty) + ; return (HsIsString s (HsApp (noLoc fr') (nlHsLit (HsString s)))) } + + | Just expr <- shortCutStringLit s res_ty + = return (HsIsString s expr) + + | otherwise + = do { expr <- newLitInst orig lit res_ty + ; return (HsIsString s expr) } + newLitInst :: InstOrigin -> HsOverLit Name -> BoxyRhoType -> TcM (HsExpr TcId) newLitInst orig lit res_ty -- Make a LitInst = do { loc <- getInstLoc orig ; res_tau <- zapToMonotype res_ty ; new_uniq <- newUnique ; let lit_nm = mkSystemVarName new_uniq FSLIT("lit") - lit_inst = LitInst lit_nm lit res_tau loc + lit_inst = LitInst {tci_name = lit_nm, tci_lit = lit, + tci_ty = res_tau, tci_loc = loc} ; extendLIE lit_inst ; return (HsVar (instToId lit_inst)) } \end{code} @@ -909,7 +922,7 @@ existentialExplode pat text "In the binding group for"]) 4 (ppr pat) -sigPatCtxt bound_ids bound_tvs pat_tys body_ty tidy_env +sigPatCtxt pats bound_tvs pat_tys body_ty tidy_env = do { pat_tys' <- mapM zonkTcType pat_tys ; body_ty' <- zonkTcType body_ty ; let (env1, tidy_tys) = tidyOpenTypes tidy_env (map idType show_ids) @@ -922,8 +935,9 @@ sigPatCtxt bound_ids bound_tvs pat_tys body_ty tidy_env ptext SLIT("The body has type:") <+> ppr tidy_body_ty ]) } where + bound_ids = collectPatsBinders pats show_ids = filter is_interesting bound_ids - is_interesting id = any (`elemVarSet` idFreeTyVars id) bound_tvs + is_interesting id = any (`elemVarSet` varTypeTyVars id) bound_tvs ppr_id id ty = ppr id <+> dcolon <+> ppr ty -- Don't zonk the types so we get the separate, un-unified versions