X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcPat.lhs;h=e7fd6ca6d1c939a86acfc85ab7bfad6bba24f431;hb=8ffdb8eed6b38db00761093889f5cddbe8ca1d60;hp=8b99276c770665192d80e9f2448b29f7a0c0fbc9;hpb=a8ac6f833f37a0507df0a84fbbff1d1ff1936533;p=ghc-hetmet.git diff --git a/compiler/typecheck/TcPat.lhs b/compiler/typecheck/TcPat.lhs index 8b99276..e7fd6ca 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(..), ExprCoFn(..), - 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, - 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 @@ -569,9 +568,10 @@ 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 origin data_con ctxt_res_tys + ; addDataConStupidTheta data_con ctxt_res_tys ; return (unwrapFamInstScrutinee tycon 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. -- @@ -616,7 +614,7 @@ tcConPat pstate con_span data_con tycon pat_ty arg_pats thing_inside -- NB: We can use CoPat directly, rather than mkCoPat, as we know the -- coercion is not the identity; mkCoPat is inconvenient as it -- wants a located pattern. - = CoPat (ExprCoFn $ mkTyConApp co_con args) -- co fam ty to repr ty + = CoPat (WpCo $ mkTyConApp co_con args) -- co fam ty to repr ty (pat {pat_ty = mkTyConApp tycon args}) -- representation type pat_ty -- family inst type | otherwise @@ -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 @@ -697,13 +696,16 @@ tcConArg (arg_pat, arg_ty) pstate thing_inside \end{code} \begin{code} -addDataConStupidTheta :: InstOrigin -> DataCon -> [TcType] -> TcM () +addDataConStupidTheta :: DataCon -> [TcType] -> TcM () -- Instantiate the "stupid theta" of the data con, and throw -- the constraints into the constraint set -addDataConStupidTheta origin data_con inst_tys +addDataConStupidTheta data_con inst_tys | null stupid_theta = return () | otherwise = instStupidTheta origin inst_theta where + origin = OccurrenceOf (dataConName data_con) + -- The origin should always report "occurrence of C" + -- even when C occurs in a pattern stupid_theta = dataConStupidTheta data_con tenv = zipTopTvSubst (dataConUnivTyVars data_con) inst_tys inst_theta = substTheta tenv stupid_theta @@ -817,7 +819,8 @@ newLitInst orig lit res_ty -- Make a LitInst ; 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} @@ -906,7 +909,7 @@ 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) @@ -919,8 +922,9 @@ 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