X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcEnv.lhs;h=a23795cf6d3975b0546b4df357df73ec3959a8a4;hp=787616aa3e60c0c9f6a106cae148ffe898c85371;hb=3f1b316d7035c55cd712cd39a9981339bcef2e8c;hpb=940524aec90652b5ef81789c9a453c57c0e42cc9 diff --git a/compiler/typecheck/TcEnv.lhs b/compiler/typecheck/TcEnv.lhs index 787616a..a23795c 100644 --- a/compiler/typecheck/TcEnv.lhs +++ b/compiler/typecheck/TcEnv.lhs @@ -3,6 +3,13 @@ % \begin{code} +{-# OPTIONS -w #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module TcEnv( TyThing(..), TcTyThing(..), TcId, @@ -22,6 +29,7 @@ module TcEnv( -- Local environment tcExtendKindEnv, tcExtendKindEnvTvs, tcExtendTyVarEnv, tcExtendTyVarEnv2, + tcExtendGhciEnv, tcExtendIdEnv, tcExtendIdEnv1, tcExtendIdEnv2, tcLookup, tcLookupLocated, tcLookupLocalIds, tcLookupId, tcLookupTyVar, getScopedTyVarBinds, @@ -39,10 +47,10 @@ module TcEnv( -- Template Haskell stuff checkWellStaged, spliceOK, bracketOK, tcMetaTy, thLevel, - topIdLvl, + topIdLvl, thTopLevelId, -- New Ids - newLocalName, newDFunName, newFamInstTyConName + newLocalName, newDFunName, newFamInstTyConName, ) where #include "HsVersions.h" @@ -54,6 +62,7 @@ import TcRnMonad import TcMType import TcType import TcGadt +-- import TcSuspension import qualified Type import Var import VarSet @@ -63,6 +72,8 @@ import InstEnv import FamInstEnv import DataCon import TyCon +import TypeRep +import Coercion import Class import Name import PrelNames @@ -71,6 +82,7 @@ import OccName import HscTypes import SrcLoc import Outputable +import Maybes \end{code} @@ -98,7 +110,7 @@ tcLookupGlobal name = do { env <- getGblEnv -- Try local envt - ; case lookupNameEnv (tcg_type_env env) name of { + ; case lookupNameEnv (tcg_type_env env) name of { Just thing -> return thing ; Nothing -> do @@ -111,12 +123,12 @@ tcLookupGlobal name -- Should it have been in the local envt? { case nameModule_maybe name of - Nothing -> notFound name -- Internal names can happen in GHCi + Nothing -> notFound name env -- Internal names can happen in GHCi Just mod | mod == tcg_mod env -- Names from this module - -> notFound name -- should be in tcg_type_env + -> notFound name env -- should be in tcg_type_env | mod == thFAKE -- Names bound in TH declaration brackets - -> notFound name -- should be in tcg_env + -> notFound name env -- should be in tcg_env | otherwise -> tcImportDecl name -- Go find it in an interface }}}}} @@ -158,31 +170,34 @@ tcLookupLocatedClass = addLocM tcLookupClass tcLookupLocatedTyCon :: Located Name -> TcM TyCon tcLookupLocatedTyCon = addLocM tcLookupTyCon --- Look up the representation tycon of a family instance. --- Return the rep tycon and the corresponding rep args -tcLookupFamInst :: TyCon -> [Type] -> TcM (TyCon, [Type]) +-- Look up the instance tycon of a family instance. +-- +-- The match must be unique - ie, match exactly one instance - but the +-- type arguments used for matching may be more specific than those of +-- the family instance declaration. +-- +-- Return the instance tycon and its type instance. For example, if we have +-- +-- tcLookupFamInst 'T' '[Int]' yields (':R42T', 'Int') +-- +-- then we have a coercion (ie, type instance of family instance coercion) +-- +-- :Co:R42T Int :: T [Int] ~ :R42T Int +-- +-- which implies that :R42T was declared as 'data instance T [a]'. +-- +tcLookupFamInst :: TyCon -> [Type] -> TcM (Maybe (TyCon, [Type])) tcLookupFamInst tycon tys | not (isOpenTyCon tycon) - = return (tycon, tys) + = return Nothing | otherwise = do { env <- getGblEnv ; eps <- getEps ; let instEnv = (eps_fam_inst_env eps, tcg_fam_inst_env env) ; case lookupFamInstEnv instEnv tycon tys of - - [(subst, fam_inst)] | variable_only_subst -> - return (rep_tc, substTyVars subst (tyConTyVars rep_tc)) - where -- NB: assumption is that (tyConTyVars rep_tc) is in - -- the domain of the substitution - rep_tc = famInstTyCon fam_inst - subst_domain = varEnvElts . getTvSubstEnv $ subst - tvs = map (Type.getTyVar "tcLookupFamInst") - subst_domain - variable_only_subst = all Type.isTyVarTy subst_domain && - sizeVarSet (mkVarSet tvs) == length tvs - -- renaming may have no repetitions - - other -> famInstNotFound tycon tys other + [(fam_inst, rep_tys)] -> return $ Just (famInstTyCon fam_inst, + rep_tys) + other -> return Nothing } \end{code} @@ -329,12 +344,6 @@ getScopedTyVarBinds \begin{code} tcExtendIdEnv :: [TcId] -> TcM a -> TcM a --- Invariant: the TcIds are fully zonked. Reasons: --- (a) The kinds of the forall'd type variables are defaulted --- (see Kind.defaultKind, done in zonkQuantifiedTyVar) --- (b) There are no via-Indirect occurrences of the bound variables --- in the types, because instantiation does not look through such things --- (c) The call to tyVarsOfTypes is ok without looking through refs tcExtendIdEnv ids thing_inside = tcExtendIdEnv2 [(idName id, id) | id <- ids] thing_inside tcExtendIdEnv1 :: Name -> TcId -> TcM a -> TcM a @@ -343,25 +352,48 @@ tcExtendIdEnv1 name id thing_inside = tcExtendIdEnv2 [(name,id)] thing_inside tcExtendIdEnv2 :: [(Name,TcId)] -> TcM a -> TcM a -- Invariant: the TcIds are fully zonked (see tcExtendIdEnv above) tcExtendIdEnv2 names_w_ids thing_inside - = getLclEnv `thenM` \ env -> - let - extra_global_tyvars = tcTyVarsOfTypes [idType id | (_,id) <- names_w_ids] - th_lvl = thLevel (tcl_th_ctxt env) - extra_env = [ (name, ATcId { tct_id = id, - tct_level = th_lvl, - tct_type = id_ty, - tct_co = if isRefineableTy id_ty - then Just idHsWrapper - else Nothing }) - | (name,id) <- names_w_ids, let id_ty = idType id] - le' = extendNameEnvList (tcl_env env) extra_env - rdr_env' = extendLocalRdrEnv (tcl_rdr env) [name | (name,_) <- names_w_ids] - in - traceTc (text "env2") `thenM_` - traceTc (text "env3" <+> ppr extra_env) `thenM_` - tc_extend_gtvs (tcl_tyvars env) extra_global_tyvars `thenM` \ gtvs' -> - (traceTc (text "env4") `thenM_` - setLclEnv (env {tcl_env = le', tcl_tyvars = gtvs', tcl_rdr = rdr_env'}) thing_inside) + = do { env <- getLclEnv + ; tc_extend_local_id_env env (thLevel (tcl_th_ctxt env)) names_w_ids thing_inside } + +tcExtendGhciEnv :: [TcId] -> TcM a -> TcM a +-- Used to bind Ids for GHCi identifiers bound earlier in the user interaction +-- Note especially that we bind them at TH level 'impLevel'. That's because it's +-- OK to use a variable bound earlier in the interaction in a splice, becuase +-- GHCi has already compiled it to bytecode +tcExtendGhciEnv ids thing_inside + = do { env <- getLclEnv + ; tc_extend_local_id_env env impLevel [(idName id, id) | id <- ids] thing_inside } + +tc_extend_local_id_env -- This is the guy who does the work + :: TcLclEnv + -> ThLevel + -> [(Name,TcId)] + -> TcM a -> TcM a +-- Invariant: the TcIds are fully zonked. Reasons: +-- (a) The kinds of the forall'd type variables are defaulted +-- (see Kind.defaultKind, done in zonkQuantifiedTyVar) +-- (b) There are no via-Indirect occurrences of the bound variables +-- in the types, because instantiation does not look through such things +-- (c) The call to tyVarsOfTypes is ok without looking through refs + +tc_extend_local_id_env env th_lvl names_w_ids thing_inside + = do { traceTc (text "env2") + ; traceTc (text "env3" <+> ppr extra_env) + ; gtvs' <- tc_extend_gtvs (tcl_tyvars env) extra_global_tyvars + ; let env' = env {tcl_env = le', tcl_tyvars = gtvs', tcl_rdr = rdr_env'} + ; setLclEnv env' thing_inside } + where + extra_global_tyvars = tcTyVarsOfTypes [idType id | (_,id) <- names_w_ids] + extra_env = [ (name, ATcId { tct_id = id, + tct_level = th_lvl, + tct_type = id_ty, + tct_co = case isRefineableTy id_ty of + (True,_) -> Unrefineable + (_,True) -> Rigid idHsWrapper + _ -> Wobbly}) + | (name,id) <- names_w_ids, let id_ty = idType id] + le' = extendNameEnvList (tcl_env env) extra_env + rdr_env' = extendLocalRdrEnv (tcl_rdr env) [name | (name,_) <- names_w_ids] \end{code} @@ -423,20 +455,30 @@ find_thing _ _ thing = pprPanic "find_thing" (ppr thing) \end{code} \begin{code} -refineEnvironment :: Refinement -> TcM a -> TcM a +refineEnvironment + :: Refinement + -> Bool -- whether type equations are involved + -> TcM a + -> TcM a -- I don't think I have to refine the set of global type variables in scope -- Reason: the refinement never increases that set -refineEnvironment reft thing_inside - | isEmptyRefinement reft -- Common case +refineEnvironment reft otherEquations thing_inside + | isEmptyRefinement reft -- Common case + , not otherEquations = thing_inside | otherwise = do { env <- getLclEnv ; let le' = mapNameEnv refine (tcl_env env) ; setLclEnv (env {tcl_env = le'}) thing_inside } where - refine elt@(ATcId { tct_co = Just co, tct_type = ty }) + refine elt@(ATcId { tct_co = Rigid co, tct_type = ty }) | Just (co', ty') <- refineType reft ty - = elt { tct_co = Just (WpCo co' <.> co), tct_type = ty' } + = elt { tct_co = Rigid (WpCo co' <.> co), tct_type = ty' } + refine elt@(ATcId { tct_co = Wobbly}) +-- Main new idea: make wobbly things invisible whenever there +-- is a refinement of any sort +-- | otherEquations + = elt { tct_co = WobblyInvisible} refine (ATyVar tv ty) | Just (_, ty') <- refineType reft ty = ATyVar tv ty' -- Ignore the coercion that refineType returns @@ -511,12 +553,12 @@ thLevel (Brack l _ _) = l checkWellStaged :: SDoc -- What the stage check is for - -> ThLevel -- Binding level + -> ThLevel -- Binding level (increases inside brackets) -> ThStage -- Use stage -> TcM () -- Fail if badly staged, adding an error checkWellStaged pp_thing bind_lvl use_stage - | bind_lvl <= use_lvl -- OK! - = returnM () + | use_lvl >= bind_lvl -- OK! Used later than bound + = returnM () -- E.g. \x -> [| $(f x) |] | bind_lvl == topLevel -- GHC restriction on top level splices = failWithTc $ @@ -524,7 +566,7 @@ checkWellStaged pp_thing bind_lvl use_stage nest 2 (ptext SLIT("is used in a top-level splice, and must be imported, not defined locally"))] | otherwise -- Badly staged - = failWithTc $ + = failWithTc $ -- E.g. \x -> $(f x) ptext SLIT("Stage error:") <+> pp_thing <+> hsep [ptext SLIT("is bound at stage") <+> ppr bind_lvl, ptext SLIT("but used at stage") <+> ppr use_lvl] @@ -562,6 +604,10 @@ tcMetaTy :: Name -> TcM Type tcMetaTy tc_name = tcLookupTyCon tc_name `thenM` \ t -> returnM (mkTyConApp t []) + +thTopLevelId :: Id -> Bool +-- See Note [What is a top-level Id?] in TcSplice +thTopLevelId id = isGlobalId id || isExternalName (idName id) \end{code} @@ -593,30 +639,20 @@ iDFunId info = instanceDFunId (iSpec info) data InstBindings = VanillaInst -- The normal case - (LHsBinds Name) -- Bindings + (LHsBinds Name) -- Bindings for the instance methods [LSig Name] -- User pragmas recorded for generating -- specialised instances | NewTypeDerived -- Used for deriving instances of newtypes, where the -- witness dictionary is identical to the argument -- dictionary. Hence no bindings, no pragmas. - (Maybe [PredType]) - -- Nothing => The newtype-derived instance involves type variables, - -- and the dfun has a type like df :: forall a. Eq a => Eq (T a) - -- Just (r:scs) => The newtype-defined instance has no type variables - -- so the dfun is just a constant, df :: Eq T - -- In this case we need to know waht the rep dict, r, and the - -- superclasses, scs, are. (In the Nothing case these are in the - -- dict fun's type.) - -- Invariant: these PredTypes have no free variables - -- NB: In both cases, the representation dict is the *first* dict. pprInstInfo info = vcat [ptext SLIT("InstInfo:") <+> ppr (idType (iDFunId info))] pprInstInfoDetails info = pprInstInfo info $$ nest 2 (details (iBinds info)) where - details (VanillaInst b _) = pprLHsBinds b - details (NewTypeDerived _) = text "Derived from the representation type" + details (VanillaInst b _) = pprLHsBinds b + details NewTypeDerived = text "Derived from the representation type" simpleInstInfoClsTy :: InstInfo -> (Class, Type) simpleInstInfoClsTy info = case instanceHead (iSpec info) of @@ -676,18 +712,13 @@ pprBinders :: [Name] -> SDoc pprBinders [bndr] = quotes (ppr bndr) pprBinders bndrs = pprWithCommas ppr bndrs -notFound name - = failWithTc (ptext SLIT("GHC internal error:") <+> quotes (ppr name) <+> - ptext SLIT("is not in scope")) +notFound name env + = failWithTc (vcat[ptext SLIT("GHC internal error:") <+> quotes (ppr name) <+> + ptext SLIT("is not in scope during type checking, but it passed the renamer"), + ptext SLIT("tcg_type_env of environment:") <+> ppr (tcg_type_env env)] + ) wrongThingErr expected thing name = failWithTc (pprTcTyThingCategory thing <+> quotes (ppr name) <+> ptext SLIT("used as a") <+> text expected) - -famInstNotFound tycon tys what - = failWithTc (msg <+> quotes (pprTypeApp (ppr tycon) tys)) - where - msg = ptext $ if length what > 1 - then SLIT("More than one family instance for") - else SLIT("No family instance exactly matching") \end{code}