+%
+% (c) The University of Glasgow 2006
+%
+
\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,
tcLookupLocatedGlobal, tcLookupGlobal,
tcLookupField, tcLookupTyCon, tcLookupClass, tcLookupDataCon,
tcLookupLocatedGlobalId, tcLookupLocatedTyCon,
- tcLookupLocatedClass,
+ tcLookupLocatedClass, tcLookupFamInst,
-- Local environment
tcExtendKindEnv, tcExtendKindEnvTvs,
tcExtendTyVarEnv, tcExtendTyVarEnv2,
+ tcExtendGhciEnv,
tcExtendIdEnv, tcExtendIdEnv1, tcExtendIdEnv2,
tcLookup, tcLookupLocated, tcLookupLocalIds,
tcLookupId, tcLookupTyVar, getScopedTyVarBinds,
topIdLvl,
-- New Ids
- newLocalName, newDFunName, newFamInstTyConName
+ newLocalName, newDFunName, newFamInstTyConName,
) where
#include "HsVersions.h"
-import HsSyn ( LRuleDecl, LHsBinds, LSig,
- LHsTyVarBndr, HsTyVarBndr(..), pprLHsBinds,
- idCoercion, (<.>) )
-import TcIface ( tcImportDecl )
-import IfaceEnv ( newGlobalBinder )
+import HsSyn
+import TcIface
+import IfaceEnv
import TcRnMonad
-import TcMType ( zonkTcType, zonkTcTyVarsAndFV )
-import TcType ( Type, TcKind, TcTyVar, TcTyVarSet, TcType,
- substTy, tyVarsOfType, tcTyVarsOfTypes, mkTyConApp,
- getDFunTyKey, tcTyConAppTyCon, tcGetTyVar, mkTyVarTy,
- tidyOpenType, isRefineableTy
- )
-import TcGadt ( Refinement, refineType )
-import qualified Type ( getTyVar_maybe )
-import Id ( idName, isLocalId )
-import Var ( TyVar, Id, idType, tyVarName )
+import TcMType
+import TcType
+import TcGadt
+-- import TcSuspension
+import qualified Type
+import Var
import VarSet
import VarEnv
-import RdrName ( extendLocalRdrEnv )
-import InstEnv ( Instance, DFunId, instanceDFunId, instanceHead )
-import DataCon ( DataCon )
-import TyCon ( TyCon )
-import Class ( Class )
-import Name ( Name, NamedThing(..), getSrcLoc, nameModule,
- nameOccName )
-import PrelNames ( thFAKE )
+import RdrName
+import InstEnv
+import FamInstEnv
+import DataCon
+import TyCon
+import TypeRep
+import Coercion
+import Class
+import Name
+import PrelNames
import NameEnv
-import OccName ( mkDFunOcc, occNameString, mkInstTyTcOcc )
-import HscTypes ( extendTypeEnvList, lookupType, TyThing(..),
- ExternalPackageState(..) )
-import SrcLoc ( SrcLoc, Located(..) )
+import OccName
+import HscTypes
+import SrcLoc
import Outputable
+import Maybes
\end{code}
= 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
Nothing -> do
-- Should it have been in the local envt?
- { let mod = nameModule name
- ; if mod == tcg_mod env || mod == thFAKE then
- notFound name -- It should be local, so panic
- -- The thFAKE possibility is because it
- -- might be in a declaration bracket
- else
- tcImportDecl name -- Go find it in an interface
+ { case nameModule_maybe name of
+ Nothing -> notFound name env -- Internal names can happen in GHCi
+
+ Just mod | mod == tcg_mod env -- Names from this module
+ -> notFound name env -- should be in tcg_type_env
+ | mod == thFAKE -- Names bound in TH declaration brackets
+ -> notFound name env -- should be in tcg_env
+ | otherwise
+ -> tcImportDecl name -- Go find it in an interface
}}}}}
tcLookupField :: Name -> TcM Id -- Returns the selector Id
tcLookupLocatedTyCon :: Located Name -> TcM TyCon
tcLookupLocatedTyCon = addLocM tcLookupTyCon
+
+-- 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 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
+ [(fam_inst, rep_tys)] -> return $ Just (famInstTyCon fam_inst,
+ rep_tys)
+ other -> return Nothing
+ }
\end{code}
%************************************************************************
\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
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 idCoercion
- 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}
Just d -> go tidy_env1 (d:acc) things
Nothing -> go tidy_env1 acc things
- ignore_it ty = not (tvs `intersectsVarSet` tyVarsOfType ty)
+ ignore_it ty = tvs `disjointVarSet` tyVarsOfType ty
-----------------------
find_thing ignore_it tidy_env (ATcId { tct_id = id })
\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
+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 })
- = let (co', ty') = refineType reft ty
- in elt { tct_co = Just (co' <.> co), tct_type = ty' }
- refine (ATyVar tv ty) = ATyVar tv (snd (refineType reft ty))
- -- Ignore the coercion that refineType returns
- refine elt = elt
+ refine elt@(ATcId { tct_co = Rigid co, tct_type = ty })
+ | Just (co', ty') <- refineType reft 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
+
+ refine elt = elt -- Common case
\end{code}
%************************************************************************
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 $
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]
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
- TyCon -- tycon for the newtype
- -- Used for deriving instances of newtypes, where the
- [Type] -- witness dictionary is identical to the argument
- -- dictionary. Hence no bindings, no pragmas
- -- The [Type] are the representation types
- -- See notes in TcDeriv
+ | NewTypeDerived -- Used for deriving instances of newtypes, where the
+ -- witness dictionary is identical to the argument
+ -- dictionary. Hence no bindings, no pragmas.
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
name, like otber top-level names, and hence must be made with newGlobalBinder.
\begin{code}
-newDFunName :: Class -> [Type] -> SrcLoc -> TcM Name
+newDFunName :: Class -> [Type] -> SrcSpan -> TcM Name
newDFunName clas (ty:_) loc
= do { index <- nextDFunIndex
; is_boot <- tcIsHsBoot
occNameString (getDFunTyKey ty)
dfun_occ = mkDFunOcc info_string is_boot index
- ; newGlobalBinder mod dfun_occ Nothing loc }
+ ; newGlobalBinder mod dfun_occ loc }
newDFunName clas [] loc = pprPanic "newDFunName" (ppr clas <+> ppr loc)
\end{code}
-Make a name for the representation tycon of a data/newtype instance. It's an
+Make a name for the representation tycon of a family instance. It's an
*external* name, like otber top-level names, and hence must be made with
newGlobalBinder.
\begin{code}
-newFamInstTyConName :: Name -> SrcLoc -> TcM Name
+newFamInstTyConName :: Name -> SrcSpan -> TcM Name
newFamInstTyConName tc_name loc
= do { index <- nextDFunIndex
; mod <- getModule
; let occ = nameOccName tc_name
- ; newGlobalBinder mod (mkInstTyTcOcc index occ) Nothing loc }
+ ; newGlobalBinder mod (mkInstTyTcOcc index occ) loc }
\end{code}
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) <+>
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