{- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 -} --{-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE DeriveFunctor #-} {-# LANGUAGE BangPatterns #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE MagicHash #-} {-# LANGUAGE OverloadedStrings #-} -- | -- #name_types# -- GHC uses several kinds of name internally: -- -- * 'GHC.Types.Name.Occurrence.OccName' represents names as strings with just a little more information: -- the \"namespace\" that the name came from, e.g. the namespace of value, type constructors or -- data constructors -- -- * 'GHC.Types.Name.Reader.RdrName': see "GHC.Types.Name.Reader#name_types" -- -- * 'GHC.Types.Name.Name': see "GHC.Types.Name#name_types" -- -- * 'GHC.Types.Id.Id': see "GHC.Types.Id#name_types" -- -- * 'GHC.Types.Var.Var': see "GHC.Types.Var#name_types" module GHC.Types.Name.Occurrence ( -- * The 'NameSpace' type NameSpace, -- Abstract -- ** Construction -- $real_vs_source_data_constructors tcName, clsName, tcClsName, dataName, varName, fieldName, tvName, srcDataName, -- ** Pretty Printing pprNameSpace, pprNonVarNameSpace, pprNameSpaceBrief, -- * The 'OccName' type OccName, -- Abstract, instance of Outputable pprOccName, occNameMangledFS, -- ** Construction mkOccName, mkOccNameFS, mkVarOcc, mkVarOccFS, mkRecFieldOcc, mkRecFieldOccFS, mkDataOcc, mkDataOccFS, mkTyVarOcc, mkTyVarOccFS, mkTcOcc, mkTcOccFS, mkClsOcc, mkClsOccFS, mkDFunOcc, setOccNameSpace, demoteOccName, demoteOccTvName, promoteOccName, varToRecFieldOcc, recFieldToVarOcc, HasOccName(..), -- ** Derived 'OccName's isDerivedOccName, mkDataConWrapperOcc, mkWorkerOcc, mkMatcherOcc, mkBuilderOcc, mkDefaultMethodOcc, isDefaultMethodOcc, isTypeableBindOcc, mkNewTyCoOcc, mkClassOpAuxOcc, mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkRepEqOcc, mkGenR, mkGen1R, mkDataTOcc, mkDataCOcc, mkDataConWorkerOcc, mkSuperDictSelOcc, mkSuperDictAuxOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc, mkInstTyCoOcc, mkEqPredCoOcc, mkTyConRepOcc, -- ** Deconstruction occNameFS, occNameString, occNameSpace, isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc, isFieldOcc, fieldOcc_maybe, parenSymOcc, startsWithUnderscore, isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace, isFieldNameSpace, isTermVarOrFieldNameSpace, -- * The 'OccEnv' type OccEnv, emptyOccEnv, unitOccEnv, extendOccEnv, mapOccEnv, strictMapOccEnv, mapMaybeOccEnv, lookupOccEnv, lookupOccEnv_AllNameSpaces, lookupOccEnv_WithFields, lookupFieldsOccEnv, mkOccEnv, mkOccEnv_C, extendOccEnvList, elemOccEnv, nonDetOccEnvElts, nonDetFoldOccEnv, plusOccEnv, plusOccEnv_C, extendOccEnv_Acc, filterOccEnv, delListFromOccEnv, delFromOccEnv, alterOccEnv, minusOccEnv, minusOccEnv_C, minusOccEnv_C_Ns, pprOccEnv, forceOccEnv, intersectOccEnv_C, -- * The 'OccSet' type OccSet, emptyOccSet, unitOccSet, mkOccSet, extendOccSet, extendOccSetList, unionOccSets, unionManyOccSets, elemOccSet, isEmptyOccSet, -- * Dealing with main mainOcc, ppMainFn, -- * Tidying up TidyOccEnv, emptyTidyOccEnv, initTidyOccEnv, tidyOccName, avoidClashesOccEnv, delTidyOccEnvList, -- FsEnv FastStringEnv, emptyFsEnv, lookupFsEnv, extendFsEnv, mkFsEnv ) where import GHC.Prelude import GHC.Builtin.Uniques import GHC.Utils.Misc import GHC.Types.Unique import GHC.Types.Unique.FM import GHC.Types.Unique.Set import GHC.Data.FastString import GHC.Data.FastString.Env import GHC.Utils.Outputable import GHC.Utils.Lexeme import GHC.Utils.Binary import GHC.Utils.Panic.Plain import Control.DeepSeq import Data.Char import Data.Data import qualified Data.Semigroup as S import GHC.Exts( Int(I#), dataToTag# ) {- ************************************************************************ * * \subsection{Name space} * * ************************************************************************ -} data NameSpace -- | Variable name space (including "real" data constructors). = VarName -- | Record field namespace for the given record. | FldName { fldParent :: !FastString -- ^ The textual name of the parent of the field. -- -- - For a field of a datatype, this is the name of the first constructor -- of the datatype (regardless of whether this constructor has this field). -- - For a field of a pattern synonym, this is the name of the pattern synonym. } -- | "Source" data constructor namespace. | DataName -- | Type variable namespace. | TvName -- | Type constructor and class namespace. | TcClsName -- Haskell has type constructors and classes in the same namespace, for now. deriving Eq instance Ord NameSpace where compare ns1 ns2 = case compare (I# (dataToTag# ns1)) (I# (dataToTag# ns2)) of LT -> LT GT -> GT EQ | FldName { fldParent = p1 } <- ns1 , FldName { fldParent = p2 } <- ns2 -> lexicalCompareFS p1 p2 | otherwise -> EQ instance Uniquable NameSpace where getUnique (FldName fs) = mkFldNSUnique fs getUnique VarName = varNSUnique getUnique DataName = dataNSUnique getUnique TvName = tvNSUnique getUnique TcClsName = tcNSUnique instance NFData NameSpace where rnf VarName = () rnf (FldName par) = rnf par rnf DataName = () rnf TvName = () rnf TcClsName = () {- Note [Data Constructors] ~~~~~~~~~~~~~~~~~~~~~~~~ see also: Note [Data Constructor Naming] in GHC.Core.DataCon $real_vs_source_data_constructors There are two forms of data constructor: [Source data constructors] The data constructors mentioned in Haskell source code [Real data constructors] The data constructors of the representation type, which may not be the same as the source type For example: > data T = T !(Int, Int) The source datacon has type @(Int, Int) -> T@ The real datacon has type @Int -> Int -> T@ GHC chooses a representation based on the strictness etc. Note [Record field namespacing] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Record fields have a separate namespace from variables, to support DuplicateRecordFields, e.g. in data X = MkX { fld :: Int } data Y = MkY { fld :: Bool } f x = x { fld = 3 } g y = y { fld = False } we want the two occurrences of "fld" to refer to the field names associated with the corresponding data type. The namespace for a record field is as follows: - for a data type, it is the textual name of the first constructor of the datatype, whether this constructor has this field or not; - for a pattern synonym, it is the textual name of the pattern synonym itself. Record fields are initially parsed as variables, but the renamer resolves their namespace in GHC.Rename.Names.newRecordFieldLabel, which is called when renaming record data declarations and record pattern synonym declarations. To illustrate the namespacing, consider the record field "fld" in the following datatype data instance A Int Bool Char = MkA1 | MkA2 { fld :: Int } | MkA3 { bar :: Bool, fld :: Int } Its namespace is `FldName "MkA1"`. This is a convention used throughout GHC to circumvent the fact that we don't have a way to refer to the type constructor "A Int Bool Char" in the renamer, as data family instances only get given 'Name's in the typechecker. -} tcName, clsName, tcClsName :: NameSpace dataName, srcDataName :: NameSpace tvName, varName :: NameSpace -- Though type constructors and classes are in the same name space now, -- the NameSpace type is abstract, so we can easily separate them later tcName = TcClsName -- Type constructors clsName = TcClsName -- Classes tcClsName = TcClsName -- Not sure which! dataName = DataName srcDataName = DataName -- Haskell-source data constructors should be -- in the Data name space tvName = TvName varName = VarName fieldName :: FastString -> NameSpace fieldName = FldName isDataConNameSpace :: NameSpace -> Bool isDataConNameSpace DataName = True isDataConNameSpace _ = False isTcClsNameSpace :: NameSpace -> Bool isTcClsNameSpace TcClsName = True isTcClsNameSpace _ = False isTvNameSpace :: NameSpace -> Bool isTvNameSpace TvName = True isTvNameSpace _ = False isVarNameSpace :: NameSpace -> Bool -- Variables or type variables, but not constructors isVarNameSpace TvName = True isVarNameSpace VarName = True isVarNameSpace (FldName {}) = True isVarNameSpace _ = False -- | Is this a term variable or field name namespace? isTermVarOrFieldNameSpace :: NameSpace -> Bool isTermVarOrFieldNameSpace VarName = True isTermVarOrFieldNameSpace (FldName {}) = True isTermVarOrFieldNameSpace _ = False isValNameSpace :: NameSpace -> Bool isValNameSpace DataName = True isValNameSpace VarName = True isValNameSpace (FldName {}) = True isValNameSpace _ = False isFieldNameSpace :: NameSpace -> Bool isFieldNameSpace (FldName {}) = True isFieldNameSpace _ = False pprNameSpace :: NameSpace -> SDoc pprNameSpace DataName = text "data constructor" pprNameSpace VarName = text "variable" pprNameSpace TvName = text "type variable" pprNameSpace TcClsName = text "type constructor or class" pprNameSpace (FldName p) = text "record field of" <+> ftext p pprNonVarNameSpace :: NameSpace -> SDoc pprNonVarNameSpace VarName = empty pprNonVarNameSpace ns = pprNameSpace ns pprNameSpaceBrief :: NameSpace -> SDoc pprNameSpaceBrief DataName = char 'd' pprNameSpaceBrief VarName = char 'v' pprNameSpaceBrief TvName = text "tv" pprNameSpaceBrief TcClsName = text "tc" pprNameSpaceBrief (FldName {}) = text "fld" -- demoteNameSpace lowers the NameSpace if possible. We can not know -- in advance, since a TvName can appear in an HsTyVar. -- See Note [Demotion] in GHC.Rename.Env. demoteNameSpace :: NameSpace -> Maybe NameSpace demoteNameSpace VarName = Nothing demoteNameSpace DataName = Nothing demoteNameSpace TvName = Nothing demoteNameSpace TcClsName = Just DataName demoteNameSpace (FldName {}) = Nothing -- demoteTvNameSpace lowers the NameSpace of a type variable. -- See Note [Demotion] in GHC.Rename.Env. demoteTvNameSpace :: NameSpace -> Maybe NameSpace demoteTvNameSpace TvName = Just VarName demoteTvNameSpace VarName = Nothing demoteTvNameSpace DataName = Nothing demoteTvNameSpace TcClsName = Nothing demoteTvNameSpace (FldName {}) = Nothing -- promoteNameSpace promotes the NameSpace as follows. -- See Note [Promotion] in GHC.Rename.Env. promoteNameSpace :: NameSpace -> Maybe NameSpace promoteNameSpace DataName = Just TcClsName promoteNameSpace VarName = Just TvName promoteNameSpace TcClsName = Nothing promoteNameSpace TvName = Nothing promoteNameSpace (FldName {}) = Nothing {- ************************************************************************ * * \subsection[Name-pieces-datatypes]{The @OccName@ datatypes} * * ************************************************************************ -} -- | Occurrence Name -- -- In this context that means: -- "classified (i.e. as a type name, value name, etc) but not qualified -- and not yet resolved" data OccName = OccName { occNameSpace :: !NameSpace , occNameFS :: !FastString } instance Eq OccName where (OccName sp1 s1) == (OccName sp2 s2) = s1 == s2 && sp1 == sp2 instance Ord OccName where -- Compares lexicographically, *not* by Unique of the string compare (OccName sp1 s1) (OccName sp2 s2) = lexicalCompareFS s1 s2 S.<> compare sp1 sp2 instance Data OccName where -- don't traverse? toConstr _ = abstractConstr "OccName" gunfold _ _ = error "gunfold" dataTypeOf _ = mkNoRepType "OccName" instance HasOccName OccName where occName = id instance NFData OccName where rnf x = x `seq` () {- ************************************************************************ * * \subsection{Printing} * * ************************************************************************ -} instance Outputable OccName where ppr = pprOccName instance OutputableBndr OccName where pprBndr _ = ppr pprInfixOcc n = pprInfixVar (isSymOcc n) (ppr n) pprPrefixOcc n = pprPrefixVar (isSymOcc n) (ppr n) pprOccName :: IsLine doc => OccName -> doc pprOccName (OccName sp occ) = docWithStyle (ztext (zEncodeFS occ)) (\_ -> ftext occ <> whenPprDebug (braces (pprNameSpaceBrief sp))) {-# SPECIALIZE pprOccName :: OccName -> SDoc #-} {-# SPECIALIZE pprOccName :: OccName -> HLine #-} -- see Note [SPECIALIZE to HDoc] in GHC.Utils.Outputable -- | Mangle field names to avoid duplicate symbols. -- -- See Note [Mangling OccNames]. occNameMangledFS :: OccName -> FastString occNameMangledFS (OccName ns fs) = case ns of -- Fields need to include the constructor, to ensure that we don't define -- duplicate symbols when using DuplicateRecordFields. FldName con -> concatFS [fsLit "$fld:", con, ":", fs] -- Otherwise, we can ignore the namespace, as there is no risk of name -- clashes. _ -> fs {- Note [Mangling OccNames] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ When generating a symbol for a Name, we usually discard the NameSpace entirely (see GHC.Types.Name.pprName). This is because clashes are usually not possible, e.g. a variable and a data constructor can't clash because data constructors start with a capital letter or a colon, while variables never do. However, record field names, in the presence of DuplicateRecordFields, need this disambiguation. So, for a record field like data A = MkA { foo :: Int } we generate the symbol $fld:MkA:foo. We use the constructor 'MkA' to disambiguate, and not the TyCon A as one might naively expect: this is explained in Note [Record field namespacing]. -} {- ************************************************************************ * * \subsection{Construction} * * ************************************************************************ -} mkOccName :: NameSpace -> String -> OccName mkOccName occ_sp str = OccName occ_sp (mkFastString str) mkOccNameFS :: NameSpace -> FastString -> OccName mkOccNameFS occ_sp fs = OccName occ_sp fs mkVarOcc :: String -> OccName mkVarOcc s = mkOccName varName s mkVarOccFS :: FastString -> OccName mkVarOccFS fs = mkOccNameFS varName fs mkRecFieldOcc :: FastString -> String -> OccName mkRecFieldOcc dc = mkOccName (fieldName dc) mkRecFieldOccFS :: FastString -> FastString -> OccName mkRecFieldOccFS dc = mkOccNameFS (fieldName dc) varToRecFieldOcc :: HasDebugCallStack => FastString -> OccName -> OccName varToRecFieldOcc dc (OccName ns s) = assert makes_sense $ mkRecFieldOccFS dc s where makes_sense = case ns of VarName -> True FldName {} -> True -- NB: it's OK to change the parent data constructor, -- see e.g. test T23220 in which we construct with TH -- a datatype using the fields of a different datatype. _ -> False recFieldToVarOcc :: HasDebugCallStack => OccName -> OccName recFieldToVarOcc (OccName _ns s) = mkVarOccFS s mkDataOcc :: String -> OccName mkDataOcc = mkOccName dataName mkDataOccFS :: FastString -> OccName mkDataOccFS = mkOccNameFS dataName mkTyVarOcc :: String -> OccName mkTyVarOcc = mkOccName tvName mkTyVarOccFS :: FastString -> OccName mkTyVarOccFS fs = mkOccNameFS tvName fs mkTcOcc :: String -> OccName mkTcOcc = mkOccName tcName mkTcOccFS :: FastString -> OccName mkTcOccFS = mkOccNameFS tcName mkClsOcc :: String -> OccName mkClsOcc = mkOccName clsName mkClsOccFS :: FastString -> OccName mkClsOccFS = mkOccNameFS clsName -- demoteOccName lowers the Namespace of OccName. -- See Note [Demotion] in GHC.Rename.Env. demoteOccName :: OccName -> Maybe OccName demoteOccName (OccName space name) = do space' <- demoteNameSpace space return $ OccName space' name demoteOccTvName :: OccName -> Maybe OccName demoteOccTvName (OccName space name) = do space' <- demoteTvNameSpace space return $ OccName space' name -- promoteOccName promotes the NameSpace of OccName. -- See Note [Promotion] in GHC.Rename.Env. promoteOccName :: OccName -> Maybe OccName promoteOccName (OccName space name) = do space' <- promoteNameSpace space return $ OccName space' name {- | Other names in the compiler add additional information to an OccName. This class provides a consistent way to access the underlying OccName. -} class HasOccName name where occName :: name -> OccName {- ************************************************************************ * * Environments * * ************************************************************************ OccEnvs are used for the GlobalRdrEnv and for the envts in ModIface. Note [OccEnv] ~~~~~~~~~~~~~ An OccEnv is a map keyed on OccName. Recall that an OccEnv consists of two components: - a namespace, - a textual name (in the form of a FastString). In general, for a given textual name, there is only one appropriate namespace. However, sometimes we do get an occurrence that belongs to several namespaces: - Symbolic identifiers such as (:+) can belong to both the data constructor and type constructor/class namespaces. - With duplicate record fields, a field name can belong to several different namespaces, one for each parent datatype (or pattern synonym). So we represent an OccEnv as a nested data structure FastStringEnv (UniqFM NameSpace a) in which we can first look up the textual name, and then choose which of the namespaces are relevant. This supports the two main uses of OccEnvs: 1. One wants to look up a specific OccName in the environment, at a specific namespace. One looks up the textual name, and then the namespace. 2. One wants to look up something, but isn't sure in advance of the namespace. So one looks up the textual name, and then can decide what to do based on the returned map of namespaces. This data structure isn't performance critical in most situations, but some improvements to its performance that might be worth it are as follows: A. Use a tailor-made data structure for a map keyed on NameSpaces. Recall that we have: data IntMap a = Bin !Int !Int !(IntMap a) !(IntMap a) | Tip !Key a | Nil This is already pretty efficient for singletons, but we don't need the empty case (as we would simply omit the parent key in the OccEnv instead of storing an empty inner map). B. Always ensure the inner map (keyed on namespaces) is evaluated, i.e. is never a thunk. For this, we would need to use strict operations on the outer FastStringEnv (but we'd keep using lazy operations on the inner UniqFM). -} -- | A map keyed on 'OccName'. See Note [OccEnv]. newtype OccEnv a = MkOccEnv (FastStringEnv (UniqFM NameSpace a)) deriving Functor -- | The empty 'OccEnv'. emptyOccEnv :: OccEnv a emptyOccEnv = MkOccEnv emptyFsEnv -- | A singleton 'OccEnv'. unitOccEnv :: OccName -> a -> OccEnv a unitOccEnv (OccName ns s) a = MkOccEnv $ unitFsEnv s (unitUFM ns a) -- | Add a single element to an 'OccEnv'. extendOccEnv :: OccEnv a -> OccName -> a -> OccEnv a extendOccEnv (MkOccEnv as) (OccName ns s) a = MkOccEnv $ extendFsEnv_C plusUFM as s (unitUFM ns a) -- | Extend an 'OccEnv' by a list. -- -- 'OccName's later on in the list override earlier 'OccName's. extendOccEnvList :: OccEnv a -> [(OccName, a)] -> OccEnv a extendOccEnvList = foldl' $ \ env (occ, a) -> extendOccEnv env occ a -- | Look an element up in an 'OccEnv'. lookupOccEnv :: OccEnv a -> OccName -> Maybe a lookupOccEnv (MkOccEnv as) (OccName ns s) = do { m <- lookupFsEnv as s ; lookupUFM m ns } -- | Lookup an element in an 'OccEnv', ignoring 'NameSpace's entirely. lookupOccEnv_AllNameSpaces :: OccEnv a -> OccName -> [a] lookupOccEnv_AllNameSpaces (MkOccEnv as) (OccName _ s) = case lookupFsEnv as s of Nothing -> [] Just r -> nonDetEltsUFM r -- | Lookup an element in an 'OccEnv', looking in the record field -- namespace for a variable. lookupOccEnv_WithFields :: OccEnv a -> OccName -> [a] lookupOccEnv_WithFields env occ = case lookupOccEnv env occ of Nothing -> fieldGREs Just gre -> gre : fieldGREs where fieldGREs -- If the 'OccName' is a variable, also look up -- in the record field namespaces. | isVarOcc occ = lookupFieldsOccEnv env (occNameFS occ) | otherwise = [] -- | Look up all the record fields that match with the given 'FastString' -- in an 'OccEnv'. lookupFieldsOccEnv :: OccEnv a -> FastString -> [a] lookupFieldsOccEnv (MkOccEnv as) fld = case lookupFsEnv as fld of Nothing -> [] Just flds -> nonDetEltsUFM $ filter_flds flds -- NB: non-determinism is OK: in practice we will either end up resolving -- to a single field or throwing an error. where filter_flds = filterUFM_Directly (\ uniq _ -> isFldNSUnique uniq) -- | Create an 'OccEnv' from a list. -- -- 'OccName's later on in the list override earlier 'OccName's. mkOccEnv :: [(OccName,a)] -> OccEnv a mkOccEnv = extendOccEnvList emptyOccEnv -- | Create an 'OccEnv' from a list, combining different values -- with the same 'OccName' using the combining function. mkOccEnv_C :: (a -> a -> a) -- ^ old -> new -> result -> [(OccName,a)] -> OccEnv a mkOccEnv_C f elts = MkOccEnv $ foldl' g emptyFsEnv elts where g env (OccName ns s, a) = extendFsEnv_C (plusUFM_C $ flip f) env s (unitUFM ns a) -- | Compute whether there is a value keyed by the given 'OccName'. elemOccEnv :: OccName -> OccEnv a -> Bool elemOccEnv (OccName ns s) (MkOccEnv as) = case lookupFsEnv as s of Nothing -> False Just m -> ns `elemUFM` m -- | Fold over an 'OccEnv'. Non-deterministic, unless the folding function -- is commutative (i.e. @a1 `f` ( a2 `f` b ) == a2 `f` ( a1 `f` b )@ for all @a1@, @a2@, @b@). nonDetFoldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b nonDetFoldOccEnv f b0 (MkOccEnv as) = nonDetFoldFsEnv (flip $ nonDetFoldUFM f) b0 as -- | Obtain the elements of an 'OccEnv'. -- -- The resulting order is non-deterministic. nonDetOccEnvElts :: OccEnv a -> [a] nonDetOccEnvElts = nonDetFoldOccEnv (:) [] -- | Union of two 'OccEnv's, right-biased. plusOccEnv :: OccEnv a -> OccEnv a -> OccEnv a plusOccEnv (MkOccEnv env1) (MkOccEnv env2) = MkOccEnv $ plusFsEnv_C plusUFM env1 env2 -- | Union of two 'OccEnv's with a combining function. plusOccEnv_C :: (a->a->a) -> OccEnv a -> OccEnv a -> OccEnv a plusOccEnv_C f (MkOccEnv env1) (MkOccEnv env2) = MkOccEnv $ plusFsEnv_C (plusUFM_C f) env1 env2 -- | Map over an 'OccEnv' ('Functor' instance). mapOccEnv :: (a->b) -> OccEnv a -> OccEnv b mapOccEnv = fmap -- | 'mapMaybe' for b 'OccEnv'. mapMaybeOccEnv :: (a -> Maybe b) -> OccEnv a -> OccEnv b mapMaybeOccEnv f (MkOccEnv env) = MkOccEnv $ mapMaybeUFM g env where g as = case mapMaybeUFM f as of m' | isNullUFM m' -> Nothing | otherwise -> Just m' -- | Add a single element to an 'OccEnv', using a different function whether -- the 'OccName' already exists or not. extendOccEnv_Acc :: forall a b . (a->b->b) -- ^ add to existing -> (a->b) -- ^ new element -> OccEnv b -- ^ old -> OccName -> a -- ^ new -> OccEnv b extendOccEnv_Acc f g (MkOccEnv env) (OccName ns s) = MkOccEnv . extendFsEnv_Acc f' g' env s where f' :: a -> UniqFM NameSpace b -> UniqFM NameSpace b f' a bs = alterUFM (Just . \ case { Nothing -> g a ; Just b -> f a b }) bs ns g' a = unitUFM ns (g a) -- | Delete one element from an 'OccEnv'. delFromOccEnv :: forall a. OccEnv a -> OccName -> OccEnv a delFromOccEnv (MkOccEnv env1) (OccName ns s) = MkOccEnv $ alterFsEnv f env1 s where f :: Maybe (UniqFM NameSpace a) -> Maybe (UniqFM NameSpace a) f Nothing = Nothing f (Just m) = case delFromUFM m ns of m' | isNullUFM m' -> Nothing | otherwise -> Just m' -- | Delete multiple elements from an 'OccEnv'. delListFromOccEnv :: OccEnv a -> [OccName] -> OccEnv a delListFromOccEnv = foldl' delFromOccEnv -- | Filter out all elements in an 'OccEnv' using a predicate. filterOccEnv :: forall a. (a -> Bool) -> OccEnv a -> OccEnv a filterOccEnv f (MkOccEnv env) = MkOccEnv $ mapMaybeFsEnv g env where g :: UniqFM NameSpace a -> Maybe (UniqFM NameSpace a) g ms = case filterUFM f ms of m' | isNullUFM m' -> Nothing | otherwise -> Just m' -- | Alter an 'OccEnv', adding or removing an element at the given key. alterOccEnv :: forall a. (Maybe a -> Maybe a) -> OccEnv a -> OccName -> OccEnv a alterOccEnv f (MkOccEnv env) (OccName ns s) = MkOccEnv $ alterFsEnv g env s where g :: Maybe (UniqFM NameSpace a) -> Maybe (UniqFM NameSpace a) g Nothing = fmap (unitUFM ns) (f Nothing) g (Just m) = case alterUFM f m ns of m' | isNullUFM m' -> Nothing | otherwise -> Just m' intersectOccEnv_C :: (a -> b -> c) -> OccEnv a -> OccEnv b -> OccEnv c intersectOccEnv_C f (MkOccEnv as) (MkOccEnv bs) = MkOccEnv $ intersectUFM_C (intersectUFM_C f) as bs -- | Remove elements of the first 'OccEnv' that appear in the second 'OccEnv'. minusOccEnv :: OccEnv a -> OccEnv b -> OccEnv a minusOccEnv = minusOccEnv_C_Ns minusUFM -- | Alters (replaces or removes) those elements of the first 'OccEnv' that are -- mentioned in the second 'OccEnv'. -- -- Same idea as 'Data.Map.differenceWith'. minusOccEnv_C :: (a -> b -> Maybe a) -> OccEnv a -> OccEnv b -> OccEnv a minusOccEnv_C f = minusOccEnv_C_Ns (minusUFM_C f) minusOccEnv_C_Ns :: forall a b . (UniqFM NameSpace a -> UniqFM NameSpace b -> UniqFM NameSpace a) -> OccEnv a -> OccEnv b -> OccEnv a minusOccEnv_C_Ns f (MkOccEnv as) (MkOccEnv bs) = MkOccEnv $ minusUFM_C g as bs where g :: UniqFM NameSpace a -> UniqFM NameSpace b -> Maybe (UniqFM NameSpace a) g as bs = let m = f as bs in if isNullUFM m then Nothing else Just m instance Outputable a => Outputable (OccEnv a) where ppr x = pprOccEnv ppr x pprOccEnv :: (a -> SDoc) -> OccEnv a -> SDoc pprOccEnv ppr_elt (MkOccEnv env) = brackets $ fsep $ punctuate comma $ [ ppr uq <+> text ":->" <+> ppr_elt elt | (uq, elts) <- nonDetUFMToList env , elt <- nonDetEltsUFM elts ] instance NFData a => NFData (OccEnv a) where rnf = forceOccEnv rnf -- | Map over an 'OccEnv' strictly. strictMapOccEnv :: (a -> b) -> OccEnv a -> OccEnv b strictMapOccEnv f (MkOccEnv as) = MkOccEnv $ strictMapFsEnv (strictMapUFM f) as -- | Force an 'OccEnv' with the provided function. forceOccEnv :: (a -> ()) -> OccEnv a -> () forceOccEnv nf (MkOccEnv fs) = seqEltsUFM (seqEltsUFM nf) fs -------------------------------------------------------------------------------- type OccSet = FastStringEnv (UniqSet NameSpace) emptyOccSet :: OccSet unitOccSet :: OccName -> OccSet mkOccSet :: [OccName] -> OccSet extendOccSet :: OccSet -> OccName -> OccSet extendOccSetList :: OccSet -> [OccName] -> OccSet unionOccSets :: OccSet -> OccSet -> OccSet unionManyOccSets :: [OccSet] -> OccSet elemOccSet :: OccName -> OccSet -> Bool isEmptyOccSet :: OccSet -> Bool emptyOccSet = emptyFsEnv unitOccSet (OccName ns s) = unitFsEnv s (unitUniqSet ns) mkOccSet = extendOccSetList emptyOccSet extendOccSet occs (OccName ns s) = extendFsEnv occs s (unitUniqSet ns) extendOccSetList = foldl extendOccSet unionOccSets = plusFsEnv_C unionUniqSets unionManyOccSets = foldl' unionOccSets emptyOccSet elemOccSet (OccName ns s) occs = maybe False (elementOfUniqSet ns) $ lookupFsEnv occs s isEmptyOccSet = isNullUFM {- ************************************************************************ * * \subsection{Predicates and taking them apart} * * ************************************************************************ -} occNameString :: OccName -> String occNameString (OccName _ s) = unpackFS s setOccNameSpace :: NameSpace -> OccName -> OccName setOccNameSpace sp (OccName _ occ) = OccName sp occ isVarOcc, isTvOcc, isTcOcc, isDataOcc, isFieldOcc :: OccName -> Bool isVarOcc (OccName VarName _) = True isVarOcc _ = False isTvOcc (OccName TvName _) = True isTvOcc _ = False isTcOcc (OccName TcClsName _) = True isTcOcc _ = False isFieldOcc (OccName (FldName {}) _) = True isFieldOcc _ = False fieldOcc_maybe :: OccName -> Maybe FastString fieldOcc_maybe (OccName (FldName con) _) = Just con fieldOcc_maybe _ = Nothing -- | /Value/ 'OccNames's are those that are either in -- the variable, field name or data constructor namespaces isValOcc :: OccName -> Bool isValOcc (OccName VarName _) = True isValOcc (OccName DataName _) = True isValOcc (OccName (FldName {}) _) = True isValOcc _ = False isDataOcc (OccName DataName _) = True isDataOcc _ = False -- | Test if the 'OccName' is a data constructor that starts with -- a symbol (e.g. @:@, or @[]@) isDataSymOcc :: OccName -> Bool isDataSymOcc (OccName DataName s) = isLexConSym s isDataSymOcc _ = False -- Pretty inefficient! -- | Test if the 'OccName' is that for any operator (whether -- it is a data constructor or variable or whatever) isSymOcc :: OccName -> Bool isSymOcc (OccName ns s) = case ns of DataName -> isLexConSym s TcClsName -> isLexSym s VarName -> isLexSym s TvName -> isLexSym s FldName {} -> isLexSym s -- Pretty inefficient! parenSymOcc :: OccName -> SDoc -> SDoc -- ^ Wrap parens around an operator parenSymOcc occ doc | isSymOcc occ = parens doc | otherwise = doc startsWithUnderscore :: OccName -> Bool -- ^ Haskell 98 encourages compilers to suppress warnings about unused -- names in a pattern if they start with @_@: this implements that test startsWithUnderscore occ = case unpackFS (occNameFS occ) of '_':_ -> True _ -> False {- ************************************************************************ * * \subsection{Making system names} * * ************************************************************************ Here's our convention for splitting up the interface file name space: d... dictionary identifiers (local variables, so no name-clash worries) All of these other OccNames contain a mixture of alphabetic and symbolic characters, and hence cannot possibly clash with a user-written type or function name $f... Dict-fun identifiers (from inst decls) $dmop Default method for 'op' $pnC n'th superclass selector for class C $wf Worker for function 'f' $sf.. Specialised version of f D:C Data constructor for dictionary for class C NTCo:T Coercion connecting newtype T with its representation type TFCo:R Coercion connecting a data family to its representation type R In encoded form these appear as Zdfxxx etc :... keywords (export:, letrec: etc.) --- I THINK THIS IS WRONG! This knowledge is encoded in the following functions. @mk_deriv@ generates an @OccName@ from the prefix and a string. NB: The string must already be encoded! -} -- | Build an 'OccName' derived from another 'OccName'. -- -- Note that the pieces of the name are passed in as a @[FastString]@ so that -- the whole name can be constructed with a single 'concatFS', minimizing -- unnecessary intermediate allocations. mk_deriv :: NameSpace -> FastString -- ^ A prefix which distinguishes one sort of -- derived name from another -> [FastString] -- ^ The name we are deriving from in pieces which -- will be concatenated. -> OccName mk_deriv occ_sp sys_prefix str = mkOccNameFS occ_sp (concatFS $ sys_prefix : str) isDerivedOccName :: OccName -> Bool -- ^ Test for definitions internally generated by GHC. This predicate -- is used to suppress printing of internal definitions in some debug prints isDerivedOccName occ = case occNameString occ of '$':c:_ | isAlphaNum c -> True -- E.g. $wfoo c:':':_ | isAlphaNum c -> True -- E.g. N:blah newtype coercions _other -> False isDefaultMethodOcc :: OccName -> Bool isDefaultMethodOcc occ = case occNameString occ of '$':'d':'m':_ -> True _ -> False -- | Is an 'OccName' one of a Typeable @TyCon@ or @Module@ binding? -- This is needed as these bindings are renamed differently. -- See Note [Grand plan for Typeable] in "GHC.Tc.Instance.Typeable". isTypeableBindOcc :: OccName -> Bool isTypeableBindOcc occ = case occNameString occ of '$':'t':'c':_ -> True -- mkTyConRepOcc '$':'t':'r':_ -> True -- Module binding _ -> False mkDataConWrapperOcc, mkWorkerOcc, mkMatcherOcc, mkBuilderOcc, mkDefaultMethodOcc, mkClassDataConOcc, mkDictOcc, mkIPOcc, mkSpecOcc, mkForeignExportOcc, mkRepEqOcc, mkGenR, mkGen1R, mkDataConWorkerOcc, mkNewTyCoOcc, mkInstTyCoOcc, mkEqPredCoOcc, mkClassOpAuxOcc, mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc, mkDataTOcc, mkDataCOcc, mkTyConRepOcc :: OccName -> OccName -- These derived variables have a prefix that no Haskell value could have mkDataConWrapperOcc = mk_simple_deriv varName "$W" mkWorkerOcc = mk_simple_deriv varName "$w" mkMatcherOcc = mk_simple_deriv varName "$m" mkBuilderOcc = mk_simple_deriv varName "$b" mkDefaultMethodOcc = mk_simple_deriv varName "$dm" mkClassOpAuxOcc = mk_simple_deriv varName "$c" mkDictOcc = mk_simple_deriv varName "$d" mkIPOcc = mk_simple_deriv varName "$i" mkSpecOcc = mk_simple_deriv varName "$s" mkForeignExportOcc = mk_simple_deriv varName "$f" mkRepEqOcc = mk_simple_deriv tvName "$r" -- In RULES involving Coercible mkClassDataConOcc = mk_simple_deriv dataName "C:" -- Data con for a class mkNewTyCoOcc = mk_simple_deriv tcName "N:" -- Coercion for newtypes mkInstTyCoOcc = mk_simple_deriv tcName "D:" -- Coercion for type functions mkEqPredCoOcc = mk_simple_deriv tcName "$co" -- Used in derived instances for the names of auxiliary bindings. -- See Note [Auxiliary binders] in GHC.Tc.Deriv.Generate. mkCon2TagOcc = mk_simple_deriv varName "$con2tag_" mkTag2ConOcc = mk_simple_deriv varName "$tag2con_" mkMaxTagOcc = mk_simple_deriv varName "$maxtag_" mkDataTOcc = mk_simple_deriv varName "$t" mkDataCOcc = mk_simple_deriv varName "$c" -- TyConRepName stuff; see Note [Grand plan for Typeable] in GHC.Tc.Instance.Typeable mkTyConRepOcc occ = mk_simple_deriv varName prefix occ where prefix | isDataOcc occ = "$tc'" | otherwise = "$tc" -- Generic deriving mechanism mkGenR = mk_simple_deriv tcName "Rep_" mkGen1R = mk_simple_deriv tcName "Rep1_" mk_simple_deriv :: NameSpace -> FastString -> OccName -> OccName mk_simple_deriv sp px occ = mk_deriv sp px [occNameFS occ] -- Data constructor workers are made by setting the name space -- of the data constructor OccName (which should be a DataName) -- to VarName mkDataConWorkerOcc datacon_occ = setOccNameSpace varName datacon_occ mkSuperDictAuxOcc :: Int -> OccName -> OccName mkSuperDictAuxOcc index cls_tc_occ = mk_deriv varName "$cp" [fsLit $ show index, occNameFS cls_tc_occ] mkSuperDictSelOcc :: Int -- ^ Index of superclass, e.g. 3 -> OccName -- ^ Class, e.g. @Ord@ -> OccName -- ^ Derived 'Occname', e.g. @$p3Ord@ mkSuperDictSelOcc index cls_tc_occ = mk_deriv varName "$p" [fsLit $ show index, occNameFS cls_tc_occ] mkLocalOcc :: Unique -- ^ Unique to combine with the 'OccName' -> OccName -- ^ Local name, e.g. @sat@ -> OccName -- ^ Nice unique version, e.g. @$L23sat@ mkLocalOcc uniq occ = mk_deriv varName "$L" [fsLit $ show uniq, occNameFS occ] -- The Unique might print with characters -- that need encoding (e.g. 'z'!) -- | Derive a name for the representation type constructor of a -- @data@\/@newtype@ instance. mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@ -> OccSet -- ^ avoid these Occs -> OccName -- ^ @R:Map@ mkInstTyTcOcc str = chooseUniqueOcc tcName ('R' : ':' : str) mkDFunOcc :: String -- ^ Typically the class and type glommed together e.g. @OrdMaybe@. -- Only used in debug mode, for extra clarity -> Bool -- ^ Is this a hs-boot instance DFun? -> OccSet -- ^ avoid these Occs -> OccName -- ^ E.g. @$f3OrdMaybe@ -- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real -- thing when we compile the mother module. Reason: we don't know exactly -- what the mother module will call it. mkDFunOcc info_str is_boot set = chooseUniqueOcc VarName (prefix ++ info_str) set where prefix | is_boot = "$fx" | otherwise = "$f" {- Sometimes we need to pick an OccName that has not already been used, given a set of in-use OccNames. -} chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int) where loop occ n | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1) | otherwise = occ {- We used to add a '$m' to indicate a method, but that gives rise to bad error messages from the type checker when we print the function name or pattern of an instance-decl binding. Why? Because the binding is zapped to use the method name in place of the selector name. (See GHC.Tc.TyCl.Class.tcMethodBind) The way it is now, -ddump-xx output may look confusing, but you can always say -dppr-debug to get the uniques. However, we *do* have to zap the first character to be lower case, because overloaded constructors (blarg) generate methods too. And convert to VarName space e.g. a call to constructor MkFoo where data (Ord a) => Foo a = MkFoo a If this is necessary, we do it by prefixing '$m'. These guys never show up in error messages. What a hack. -} mkMethodOcc :: OccName -> OccName mkMethodOcc occ@(OccName VarName _) = occ mkMethodOcc occ = mk_simple_deriv varName "$m" occ {- ************************************************************************ * * \subsection{Tidying them up} * * ************************************************************************ Before we print chunks of code we like to rename it so that we don't have to print lots of silly uniques in it. But we mustn't accidentally introduce name clashes! So the idea is that we leave the OccName alone unless it accidentally clashes with one that is already in scope; if so, we tack on '1' at the end and try again, then '2', and so on till we find a unique one. There's a wrinkle for operators. Consider '>>='. We can't use '>>=1' because that isn't a single lexeme. So we encode it to 'lle' and *then* tack on the '1', if necessary. Note [TidyOccEnv] ~~~~~~~~~~~~~~~~~ type TidyOccEnv = UniqFM Int * Domain = The OccName's FastString. These FastStrings are "taken"; make sure that we don't re-use * Int, n = A plausible starting point for new guesses There is no guarantee that "FSn" is available; you must look that up in the TidyOccEnv. But it's a good place to start looking. * When looking for a renaming for "foo2" we strip off the "2" and start with "foo". Otherwise if we tidy twice we get silly names like foo23. However, if it started with digits at the end, we always make a name with digits at the end, rather than shortening "foo2" to just "foo", even if "foo" is unused. Reasons: - Plain "foo" might be used later - We use trailing digits to subtly indicate a unification variable in typechecker error message; see TypeRep.tidyTyVarBndr We have to take care though! Consider a machine-generated module (#10370) module Foo where a1 = e1 a2 = e2 ... a2000 = e2000 Then "a1", "a2" etc are all marked taken. But now if we come across "a7" again, we have to do a linear search to find a free one, "a2001". That might just be acceptable once. But if we now come across "a8" again, we don't want to repeat that search. So we use the TidyOccEnv mapping for "a" (not "a7" or "a8") as our base for starting the search; and we make sure to update the starting point for "a" after we allocate a new one. Note [Tidying multiple names at once] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider > :t (id,id,id) Every id contributes a type variable to the type signature, and all of them are "a". If we tidy them one by one, we get (id,id,id) :: (a2 -> a2, a1 -> a1, a -> a) which is a bit unfortunate, as it unfairly renames only two of them. What we would like to see is (id,id,id) :: (a3 -> a3, a2 -> a2, a1 -> a1) To achieve this, the function avoidClashesOccEnv can be used to prepare the TidyEnv, by “blocking” every name that occurs twice in the map. This way, none of the "a"s will get the privilege of keeping this name, and all of them will get a suitable number by tidyOccName. This prepared TidyEnv can then be used with tidyOccName. See tidyTyCoVarBndrs for an example where this is used. This is #12382. -} type TidyOccEnv = UniqFM FastString Int -- The in-scope OccNames -- See Note [TidyOccEnv] emptyTidyOccEnv :: TidyOccEnv emptyTidyOccEnv = emptyUFM initTidyOccEnv :: [OccName] -> TidyOccEnv -- Initialise with names to avoid! initTidyOccEnv = foldl' add emptyUFM where add env (OccName _ fs) = addToUFM env fs 1 delTidyOccEnvList :: TidyOccEnv -> [FastString] -> TidyOccEnv delTidyOccEnvList = delListFromUFM -- see Note [Tidying multiple names at once] avoidClashesOccEnv :: TidyOccEnv -> [OccName] -> TidyOccEnv avoidClashesOccEnv env occs = go env emptyUFM occs where go env _ [] = env go env seenOnce ((OccName _ fs):occs) | fs `elemUFM` env = go env seenOnce occs | fs `elemUFM` seenOnce = go (addToUFM env fs 1) seenOnce occs | otherwise = go env (addToUFM seenOnce fs ()) occs tidyOccName :: TidyOccEnv -> OccName -> (TidyOccEnv, OccName) tidyOccName env occ@(OccName occ_sp fs) | not (fs `elemUFM` env) = -- Desired OccName is free, so use it, -- and record in 'env' that it's no longer available (addToUFM env fs 1, occ) | otherwise = case lookupUFM env base1 of Nothing -> (addToUFM env base1 2, OccName occ_sp base1) Just n -> find 1 n where base :: String -- Drop trailing digits (see Note [TidyOccEnv]) base = dropWhileEndLE isDigit (unpackFS fs) base1 = mkFastString (base ++ "1") find !k !n = case elemUFM new_fs env of True -> find (k+1 :: Int) (n+k) -- By using n+k, the n argument to find goes -- 1, add 1, add 2, add 3, etc which -- moves at quadratic speed through a dense patch False -> (new_env, OccName occ_sp new_fs) where new_fs = mkFastString (base ++ show n) new_env = addToUFM (addToUFM env new_fs 1) base1 (n+1) -- Update: base1, so that next time we'll start where we left off -- new_fs, so that we know it is taken -- If they are the same (n==1), the former wins -- See Note [TidyOccEnv] {- ************************************************************************ * * Utilies for "main" * * ************************************************************************ -} mainOcc :: OccName mainOcc = mkVarOccFS (fsLit "main") ppMainFn :: OccName -> SDoc ppMainFn main_occ | main_occ == mainOcc = text "IO action" <+> quotes (ppr main_occ) | otherwise = text "main IO action" <+> quotes (ppr main_occ) {- ************************************************************************ * * Binary instance Here rather than in GHC.Iface.Binary because OccName is abstract * * ************************************************************************ -} instance Binary NameSpace where put_ bh VarName = putByte bh 0 put_ bh DataName = putByte bh 1 put_ bh TvName = putByte bh 2 put_ bh TcClsName = putByte bh 3 put_ bh (FldName parent) = do putByte bh 4 put_ bh parent get bh = do h <- getByte bh case h of 0 -> return VarName 1 -> return DataName 2 -> return TvName 3 -> return TcClsName _ -> do parent <- get bh return $ FldName { fldParent = parent } instance Binary OccName where put_ bh (OccName aa ab) = do put_ bh aa put_ bh ab get bh = do aa <- get bh ab <- get bh return (OccName aa ab)