%
% (c) The University of Glasgow, 1992-2006
%
Here we collect a variety of helper functions that construct or
analyse HsSyn. All these functions deal with generic HsSyn; functions
which deal with the intantiated versions are located elsewhere:
Parameterised by Module
---------------- -------------
RdrName parser/RdrHsSyn
Name rename/RnHsSyn
Id typecheck/TcHsSyn
\begin{code}
module HsUtils(
mkHsPar, mkHsApp, mkHsConApp, mkSimpleHsAlt,
mkSimpleMatch, unguardedGRHSs, unguardedRHS,
mkMatchGroup, mkMatch, mkHsLam, mkHsIf,
mkHsWrap, mkLHsWrap, mkHsWrapCo, mkLHsWrapCo,
coToHsWrapper, mkHsDictLet, mkHsLams,
mkHsOpApp, mkHsDo, mkHsComp, mkHsWrapPat, mkHsWrapPatCo,
nlHsTyApp, nlHsVar, nlHsLit, nlHsApp, nlHsApps, nlHsIntLit, nlHsVarApps,
nlHsDo, nlHsOpApp, nlHsLam, nlHsPar, nlHsIf, nlHsCase, nlList,
mkLHsTupleExpr, mkLHsVarTuple, missingTupArg,
mkFunBind, mkVarBind, mkHsVarBind, mk_easy_FunBind,
mkHsIntegral, mkHsFractional, mkHsIsString, mkHsString,
mkNPat, mkNPlusKPat, nlVarPat, nlLitPat, nlConVarPat, nlConPat, nlInfixConPat,
nlNullaryConPat, nlWildConPat, nlWildPat, nlTuplePat,
mkHsAppTy, userHsTyVarBndrs,
nlHsAppTy, nlHsTyVar, nlHsFunTy, nlHsTyConApp,
mkTransformStmt, mkTransformByStmt, mkExprStmt, mkBindStmt, mkLastStmt,
emptyTransStmt, mkGroupUsingStmt, mkGroupByStmt, mkGroupByUsingStmt,
emptyRecStmt, mkRecStmt,
unqualSplice, mkHsSpliceTy, mkHsSplice, mkHsQuasiQuote, unqualQuasiQuote,
noRebindableInfo,
collectLocalBinders, collectHsValBinders, collectHsBindListBinders,
collectHsBindsBinders, collectHsBindBinders, collectMethodBinders,
collectPatBinders, collectPatsBinders,
collectLStmtsBinders, collectStmtsBinders,
collectLStmtBinders, collectStmtBinders,
collectSigTysFromPats, collectSigTysFromPat,
hsTyClDeclBinders, hsTyClDeclsBinders,
hsForeignDeclsBinders, hsGroupBinders,
lStmtsImplicits, hsValBindsImplicits, lPatImplicits
) where
import HsDecls
import HsBinds
import HsExpr
import HsPat
import HsTypes
import HsLit
import RdrName
import Var
import Coercion
import TypeRep
import DataCon
import Name
import NameSet
import BasicTypes
import SrcLoc
import FastString
import Util
import Bag
import Data.Either
import Data.Maybe
\end{code}
%************************************************************************
%* *
Some useful helpers for constructing syntax
%* *
%************************************************************************
These functions attempt to construct a not-completely-useless SrcSpan
from their components, compared with the nl* functions below which
just attach noSrcSpan to everything.
\begin{code}
mkHsPar :: LHsExpr id -> LHsExpr id
mkHsPar e = L (getLoc e) (HsPar e)
mkSimpleMatch :: [LPat id] -> LHsExpr id -> LMatch id
mkSimpleMatch pats rhs
= L loc $
Match pats Nothing (unguardedGRHSs rhs)
where
loc = case pats of
[] -> getLoc rhs
(pat:_) -> combineSrcSpans (getLoc pat) (getLoc rhs)
unguardedGRHSs :: LHsExpr id -> GRHSs id
unguardedGRHSs rhs = GRHSs (unguardedRHS rhs) emptyLocalBinds
unguardedRHS :: LHsExpr id -> [LGRHS id]
unguardedRHS rhs@(L loc _) = [L loc (GRHS [] rhs)]
mkHsAppTy :: LHsType name -> LHsType name -> LHsType name
mkHsAppTy t1 t2 = addCLoc t1 t2 (HsAppTy t1 t2)
mkHsApp :: LHsExpr name -> LHsExpr name -> LHsExpr name
mkHsApp e1 e2 = addCLoc e1 e2 (HsApp e1 e2)
nlHsTyApp :: name -> [Type] -> LHsExpr name
nlHsTyApp fun_id tys = noLoc (HsWrap (mkWpTyApps tys) (HsVar fun_id))
mkLHsWrap :: HsWrapper -> LHsExpr id -> LHsExpr id
mkLHsWrap co_fn (L loc e) = L loc (mkHsWrap co_fn e)
mkHsWrap :: HsWrapper -> HsExpr id -> HsExpr id
mkHsWrap co_fn e | isIdHsWrapper co_fn = e
| otherwise = HsWrap co_fn e
mkHsWrapCo :: Coercion -> HsExpr id -> HsExpr id
mkHsWrapCo (Refl _) e = e
mkHsWrapCo co e = mkHsWrap (WpCast co) e
mkLHsWrapCo :: Coercion -> LHsExpr id -> LHsExpr id
mkLHsWrapCo (Refl _) e = e
mkLHsWrapCo co (L loc e) = L loc (mkHsWrap (WpCast co) e)
coToHsWrapper :: Coercion -> HsWrapper
coToHsWrapper (Refl _) = idHsWrapper
coToHsWrapper co = WpCast co
mkHsWrapPat :: HsWrapper -> Pat id -> Type -> Pat id
mkHsWrapPat co_fn p ty | isIdHsWrapper co_fn = p
| otherwise = CoPat co_fn p ty
mkHsWrapPatCo :: Coercion -> Pat id -> Type -> Pat id
mkHsWrapPatCo (Refl _) pat _ = pat
mkHsWrapPatCo co pat ty = CoPat (WpCast co) pat ty
mkHsLam :: [LPat id] -> LHsExpr id -> LHsExpr id
mkHsLam pats body = mkHsPar (L (getLoc body) (HsLam matches))
where
matches = mkMatchGroup [mkSimpleMatch pats body]
mkMatchGroup :: [LMatch id] -> MatchGroup id
mkMatchGroup matches = MatchGroup matches placeHolderType
mkHsLams :: [TyVar] -> [EvVar] -> LHsExpr Id -> LHsExpr Id
mkHsLams tyvars dicts expr = mkLHsWrap (mkWpTyLams tyvars <.> mkWpLams dicts) expr
mkHsDictLet :: TcEvBinds -> LHsExpr Id -> LHsExpr Id
mkHsDictLet ev_binds expr = mkLHsWrap (mkWpLet ev_binds) expr
mkHsConApp :: DataCon -> [Type] -> [HsExpr Id] -> LHsExpr Id
mkHsConApp data_con tys args
= foldl mk_app (nlHsTyApp (dataConWrapId data_con) tys) args
where
mk_app f a = noLoc (HsApp f (noLoc a))
mkSimpleHsAlt :: LPat id -> LHsExpr id -> LMatch id
mkSimpleHsAlt pat expr
= mkSimpleMatch [pat] expr
mkHsIntegral :: Integer -> PostTcType -> HsOverLit id
mkHsFractional :: FractionalLit -> PostTcType -> HsOverLit id
mkHsIsString :: FastString -> PostTcType -> HsOverLit id
mkHsDo :: HsStmtContext Name -> [LStmt id] -> HsExpr id
mkHsComp :: HsStmtContext Name -> [LStmt id] -> LHsExpr id -> HsExpr id
mkNPat :: HsOverLit id -> Maybe (SyntaxExpr id) -> Pat id
mkNPlusKPat :: Located id -> HsOverLit id -> Pat id
mkLastStmt :: LHsExpr idR -> StmtLR idL idR
mkExprStmt :: LHsExpr idR -> StmtLR idL idR
mkBindStmt :: LPat idL -> LHsExpr idR -> StmtLR idL idR
emptyRecStmt :: StmtLR idL idR
mkRecStmt :: [LStmtLR idL idR] -> StmtLR idL idR
mkHsIntegral i = OverLit (HsIntegral i) noRebindableInfo noSyntaxExpr
mkHsFractional f = OverLit (HsFractional f) noRebindableInfo noSyntaxExpr
mkHsIsString s = OverLit (HsIsString s) noRebindableInfo noSyntaxExpr
noRebindableInfo :: Bool
noRebindableInfo = error "noRebindableInfo"
mkHsDo ctxt stmts = HsDo ctxt stmts placeHolderType
mkHsComp ctxt stmts expr = mkHsDo ctxt (stmts ++ [last_stmt])
where
last_stmt = L (getLoc expr) $ mkLastStmt expr
mkHsIf :: LHsExpr id -> LHsExpr id -> LHsExpr id -> HsExpr id
mkHsIf c a b = HsIf (Just noSyntaxExpr) c a b
mkNPat lit neg = NPat lit neg noSyntaxExpr
mkNPlusKPat id lit = NPlusKPat id lit noSyntaxExpr noSyntaxExpr
mkTransformStmt :: [LStmt idL] -> LHsExpr idR -> StmtLR idL idR
mkTransformByStmt :: [LStmt idL] -> LHsExpr idR -> LHsExpr idR -> StmtLR idL idR
mkGroupUsingStmt :: [LStmt idL] -> LHsExpr idR -> StmtLR idL idR
mkGroupByStmt :: [LStmt idL] -> LHsExpr idR -> StmtLR idL idR
mkGroupByUsingStmt :: [LStmt idL] -> LHsExpr idR -> LHsExpr idR -> StmtLR idL idR
emptyTransStmt :: StmtLR idL idR
emptyTransStmt = TransStmt { trS_form = undefined, trS_stmts = [], trS_bndrs = []
, trS_by = Nothing, trS_using = noLoc noSyntaxExpr
, trS_ret = noSyntaxExpr, trS_bind = noSyntaxExpr
, trS_fmap = noSyntaxExpr }
mkTransformStmt ss u = emptyTransStmt { trS_form = ThenForm, trS_stmts = ss, trS_using = u }
mkTransformByStmt ss u b = emptyTransStmt { trS_form = ThenForm, trS_stmts = ss, trS_using = u, trS_by = Just b }
mkGroupByStmt ss b = emptyTransStmt { trS_form = GroupFormB, trS_stmts = ss, trS_by = Just b }
mkGroupUsingStmt ss u = emptyTransStmt { trS_form = GroupFormU, trS_stmts = ss, trS_using = u }
mkGroupByUsingStmt ss b u = emptyTransStmt { trS_form = GroupFormU, trS_stmts = ss
, trS_by = Just b, trS_using = u }
mkLastStmt expr = LastStmt expr noSyntaxExpr
mkExprStmt expr = ExprStmt expr noSyntaxExpr noSyntaxExpr placeHolderType
mkBindStmt pat expr = BindStmt pat expr noSyntaxExpr noSyntaxExpr
emptyRecStmt = RecStmt { recS_stmts = [], recS_later_ids = [], recS_rec_ids = []
, recS_ret_fn = noSyntaxExpr, recS_mfix_fn = noSyntaxExpr
, recS_bind_fn = noSyntaxExpr
, recS_rec_rets = [], recS_ret_ty = placeHolderType }
mkRecStmt stmts = emptyRecStmt { recS_stmts = stmts }
mkHsOpApp :: LHsExpr id -> id -> LHsExpr id -> HsExpr id
mkHsOpApp e1 op e2 = OpApp e1 (noLoc (HsVar op)) (error "mkOpApp:fixity") e2
mkHsSplice :: LHsExpr RdrName -> HsSplice RdrName
mkHsSplice e = HsSplice unqualSplice e
mkHsSpliceTy :: LHsExpr RdrName -> HsType RdrName
mkHsSpliceTy e = HsSpliceTy (mkHsSplice e) emptyFVs placeHolderKind
unqualSplice :: RdrName
unqualSplice = mkRdrUnqual (mkVarOccFS (fsLit "splice"))
mkHsQuasiQuote :: RdrName -> SrcSpan -> FastString -> HsQuasiQuote RdrName
mkHsQuasiQuote quoter span quote = HsQuasiQuote quoter span quote
unqualQuasiQuote :: RdrName
unqualQuasiQuote = mkRdrUnqual (mkVarOccFS (fsLit "quasiquote"))
mkHsString :: String -> HsLit
mkHsString s = HsString (mkFastString s)
userHsTyVarBndrs :: [Located name] -> [Located (HsTyVarBndr name)]
userHsTyVarBndrs bndrs = [ L loc (UserTyVar v placeHolderKind) | L loc v <- bndrs ]
\end{code}
%************************************************************************
%* *
Constructing syntax with no location info
%* *
%************************************************************************
\begin{code}
nlHsVar :: id -> LHsExpr id
nlHsVar n = noLoc (HsVar n)
nlHsLit :: HsLit -> LHsExpr id
nlHsLit n = noLoc (HsLit n)
nlVarPat :: id -> LPat id
nlVarPat n = noLoc (VarPat n)
nlLitPat :: HsLit -> LPat id
nlLitPat l = noLoc (LitPat l)
nlHsApp :: LHsExpr id -> LHsExpr id -> LHsExpr id
nlHsApp f x = noLoc (HsApp f x)
nlHsIntLit :: Integer -> LHsExpr id
nlHsIntLit n = noLoc (HsLit (HsInt n))
nlHsApps :: id -> [LHsExpr id] -> LHsExpr id
nlHsApps f xs = foldl nlHsApp (nlHsVar f) xs
nlHsVarApps :: id -> [id] -> LHsExpr id
nlHsVarApps f xs = noLoc (foldl mk (HsVar f) (map HsVar xs))
where
mk f a = HsApp (noLoc f) (noLoc a)
nlConVarPat :: id -> [id] -> LPat id
nlConVarPat con vars = nlConPat con (map nlVarPat vars)
nlInfixConPat :: id -> LPat id -> LPat id -> LPat id
nlInfixConPat con l r = noLoc (ConPatIn (noLoc con) (InfixCon l r))
nlConPat :: id -> [LPat id] -> LPat id
nlConPat con pats = noLoc (ConPatIn (noLoc con) (PrefixCon pats))
nlNullaryConPat :: id -> LPat id
nlNullaryConPat con = noLoc (ConPatIn (noLoc con) (PrefixCon []))
nlWildConPat :: DataCon -> LPat RdrName
nlWildConPat con = noLoc (ConPatIn (noLoc (getRdrName con))
(PrefixCon (nOfThem (dataConSourceArity con) nlWildPat)))
nlWildPat :: LPat id
nlWildPat = noLoc (WildPat placeHolderType)
nlHsDo :: HsStmtContext Name -> [LStmt id] -> LHsExpr id
nlHsDo ctxt stmts = noLoc (mkHsDo ctxt stmts)
nlHsOpApp :: LHsExpr id -> id -> LHsExpr id -> LHsExpr id
nlHsOpApp e1 op e2 = noLoc (mkHsOpApp e1 op e2)
nlHsLam :: LMatch id -> LHsExpr id
nlHsPar :: LHsExpr id -> LHsExpr id
nlHsIf :: LHsExpr id -> LHsExpr id -> LHsExpr id -> LHsExpr id
nlHsCase :: LHsExpr id -> [LMatch id] -> LHsExpr id
nlList :: [LHsExpr id] -> LHsExpr id
nlHsLam match = noLoc (HsLam (mkMatchGroup [match]))
nlHsPar e = noLoc (HsPar e)
nlHsIf cond true false = noLoc (mkHsIf cond true false)
nlHsCase expr matches = noLoc (HsCase expr (mkMatchGroup matches))
nlList exprs = noLoc (ExplicitList placeHolderType exprs)
nlHsAppTy :: LHsType name -> LHsType name -> LHsType name
nlHsTyVar :: name -> LHsType name
nlHsFunTy :: LHsType name -> LHsType name -> LHsType name
nlHsAppTy f t = noLoc (HsAppTy f t)
nlHsTyVar x = noLoc (HsTyVar x)
nlHsFunTy a b = noLoc (HsFunTy a b)
nlHsTyConApp :: name -> [LHsType name] -> LHsType name
nlHsTyConApp tycon tys = foldl nlHsAppTy (nlHsTyVar tycon) tys
\end{code}
Tuples. All these functions are *pre-typechecker* because they lack
types on the tuple.
\begin{code}
mkLHsTupleExpr :: [LHsExpr a] -> LHsExpr a
mkLHsTupleExpr [e] = e
mkLHsTupleExpr es = noLoc $ ExplicitTuple (map Present es) Boxed
mkLHsVarTuple :: [a] -> LHsExpr a
mkLHsVarTuple ids = mkLHsTupleExpr (map nlHsVar ids)
nlTuplePat :: [LPat id] -> Boxity -> LPat id
nlTuplePat pats box = noLoc (TuplePat pats box placeHolderType)
missingTupArg :: HsTupArg a
missingTupArg = Missing placeHolderType
\end{code}
%************************************************************************
%* *
Bindings; with a location at the top
%* *
%************************************************************************
\begin{code}
mkFunBind :: Located id -> [LMatch id] -> HsBind id
mkFunBind fn ms = FunBind { fun_id = fn, fun_infix = False, fun_matches = mkMatchGroup ms,
fun_co_fn = idHsWrapper, bind_fvs = placeHolderNames,
fun_tick = Nothing }
mkHsVarBind :: SrcSpan -> id -> LHsExpr id -> LHsBind id
mkHsVarBind loc var rhs = mk_easy_FunBind loc var [] rhs
mkVarBind :: id -> LHsExpr id -> LHsBind id
mkVarBind var rhs = L (getLoc rhs) $
VarBind { var_id = var, var_rhs = rhs, var_inline = False }
mk_easy_FunBind :: SrcSpan -> id -> [LPat id]
-> LHsExpr id -> LHsBind id
mk_easy_FunBind loc fun pats expr
= L loc $ mkFunBind (L loc fun) [mkMatch pats expr emptyLocalBinds]
mkMatch :: [LPat id] -> LHsExpr id -> HsLocalBinds id -> LMatch id
mkMatch pats expr binds
= noLoc (Match (map paren pats) Nothing
(GRHSs (unguardedRHS expr) binds))
where
paren lp@(L l p) | hsPatNeedsParens p = L l (ParPat lp)
| otherwise = lp
\end{code}
%************************************************************************
%* *
Collecting binders
%* *
%************************************************************************
Get all the binders in some HsBindGroups, IN THE ORDER OF APPEARANCE. eg.
...
where
(x, y) = ...
f i j = ...
[a, b] = ...
it should return [x, y, f, a, b] (remember, order important).
Note [Collect binders only after renaming]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
These functions should only be used on HsSyn *after* the renamer,
to return a [Name] or [Id]. Before renaming the record punning
and wild-card mechanism makes it hard to know what is bound.
So these functions should not be applied to (HsSyn RdrName)
\begin{code}
collectLocalBinders :: HsLocalBindsLR idL idR -> [idL]
collectLocalBinders (HsValBinds val_binds) = collectHsValBinders val_binds
collectLocalBinders (HsIPBinds _) = []
collectLocalBinders EmptyLocalBinds = []
collectHsValBinders :: HsValBindsLR idL idR -> [idL]
collectHsValBinders (ValBindsIn binds _) = collectHsBindsBinders binds
collectHsValBinders (ValBindsOut binds _) = foldr collect_one [] binds
where
collect_one (_,binds) acc = collect_binds binds acc
collectHsBindBinders :: HsBindLR idL idR -> [idL]
collectHsBindBinders b = collect_bind b []
collect_bind :: HsBindLR idL idR -> [idL] -> [idL]
collect_bind (PatBind { pat_lhs = p }) acc = collect_lpat p acc
collect_bind (FunBind { fun_id = L _ f }) acc = f : acc
collect_bind (VarBind { var_id = f }) acc = f : acc
collect_bind (AbsBinds { abs_exports = dbinds, abs_binds = _binds }) acc
= [dp | (_,dp,_,_) <- dbinds] ++ acc
collectHsBindsBinders :: LHsBindsLR idL idR -> [idL]
collectHsBindsBinders binds = collect_binds binds []
collectHsBindListBinders :: [LHsBindLR idL idR] -> [idL]
collectHsBindListBinders = foldr (collect_bind . unLoc) []
collect_binds :: LHsBindsLR idL idR -> [idL] -> [idL]
collect_binds binds acc = foldrBag (collect_bind . unLoc) acc binds
collectMethodBinders :: LHsBindsLR RdrName idR -> [Located RdrName]
collectMethodBinders binds = foldrBag get [] binds
where
get (L _ (FunBind { fun_id = f })) fs = f : fs
get _ fs = fs
collectLStmtsBinders :: [LStmtLR idL idR] -> [idL]
collectLStmtsBinders = concatMap collectLStmtBinders
collectStmtsBinders :: [StmtLR idL idR] -> [idL]
collectStmtsBinders = concatMap collectStmtBinders
collectLStmtBinders :: LStmtLR idL idR -> [idL]
collectLStmtBinders = collectStmtBinders . unLoc
collectStmtBinders :: StmtLR idL idR -> [idL]
collectStmtBinders (BindStmt pat _ _ _) = collectPatBinders pat
collectStmtBinders (LetStmt binds) = collectLocalBinders binds
collectStmtBinders (ExprStmt {}) = []
collectStmtBinders (LastStmt {}) = []
collectStmtBinders (ParStmt xs _ _ _) = collectLStmtsBinders
$ concatMap fst xs
collectStmtBinders (TransStmt { trS_stmts = stmts }) = collectLStmtsBinders stmts
collectStmtBinders (RecStmt { recS_stmts = ss }) = collectLStmtsBinders ss
collectPatBinders :: LPat a -> [a]
collectPatBinders pat = collect_lpat pat []
collectPatsBinders :: [LPat a] -> [a]
collectPatsBinders pats = foldr collect_lpat [] pats
collect_lpat :: LPat name -> [name] -> [name]
collect_lpat (L _ pat) bndrs
= go pat
where
go (VarPat var) = var : bndrs
go (WildPat _) = bndrs
go (LazyPat pat) = collect_lpat pat bndrs
go (BangPat pat) = collect_lpat pat bndrs
go (AsPat (L _ a) pat) = a : collect_lpat pat bndrs
go (ViewPat _ pat _) = collect_lpat pat bndrs
go (ParPat pat) = collect_lpat pat bndrs
go (ListPat pats _) = foldr collect_lpat bndrs pats
go (PArrPat pats _) = foldr collect_lpat bndrs pats
go (TuplePat pats _ _) = foldr collect_lpat bndrs pats
go (ConPatIn _ ps) = foldr collect_lpat bndrs (hsConPatArgs ps)
go (ConPatOut {pat_args=ps}) = foldr collect_lpat bndrs (hsConPatArgs ps)
go (LitPat _) = bndrs
go (NPat _ _ _) = bndrs
go (NPlusKPat (L _ n) _ _ _) = n : bndrs
go (SigPatIn pat _) = collect_lpat pat bndrs
go (SigPatOut pat _) = collect_lpat pat bndrs
go (QuasiQuotePat _) = bndrs
go (CoPat _ pat _) = go pat
\end{code}
Note [Dictionary binders in ConPatOut] See also same Note in DsArrows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Do *not* gather (a) dictionary and (b) dictionary bindings as binders
of a ConPatOut pattern. For most calls it doesn't matter, because
it's pre-typechecker and there are no ConPatOuts. But it does matter
more in the desugarer; for example, DsUtils.mkSelectorBinds uses
collectPatBinders. In a lazy pattern, for example f ~(C x y) = ...,
we want to generate bindings for x,y but not for dictionaries bound by
C. (The type checker ensures they would not be used.)
Desugaring of arrow case expressions needs these bindings (see DsArrows
and arrowcase1), but SPJ (Jan 2007) says it's safer for it to use its
own pat-binder-collector:
Here's the problem. Consider
data T a where
C :: Num a => a -> Int -> T a
f ~(C (n+1) m) = (n,m)
Here, the pattern (C (n+1)) binds a hidden dictionary (d::Num a),
and *also* uses that dictionary to match the (n+1) pattern. Yet, the
variables bound by the lazy pattern are n,m, *not* the dictionary d.
So in mkSelectorBinds in DsUtils, we want just m,n as the variables bound.
\begin{code}
hsGroupBinders :: HsGroup Name -> [Name]
hsGroupBinders (HsGroup { hs_valds = val_decls, hs_tyclds = tycl_decls,
hs_instds = inst_decls, hs_fords = foreign_decls })
= collectHsValBinders val_decls
++ hsTyClDeclsBinders tycl_decls inst_decls
++ hsForeignDeclsBinders foreign_decls
hsForeignDeclsBinders :: [LForeignDecl Name] -> [Name]
hsForeignDeclsBinders foreign_decls
= [n | L _ (ForeignImport (L _ n) _ _) <- foreign_decls]
hsTyClDeclsBinders :: [[LTyClDecl Name]] -> [Located (InstDecl Name)] -> [Name]
hsTyClDeclsBinders tycl_decls inst_decls
= [n | d <- instDeclATs inst_decls ++ concat tycl_decls
, L _ n <- hsTyClDeclBinders d]
hsTyClDeclBinders :: Eq name => Located (TyClDecl name) -> [Located name]
hsTyClDeclBinders (L _ (TyFamily {tcdLName = name})) = [name]
hsTyClDeclBinders (L _ (ForeignType {tcdLName = name})) = [name]
hsTyClDeclBinders (L _ (ClassDecl {tcdLName = cls_name, tcdSigs = sigs, tcdATs = ats}))
= cls_name :
concatMap hsTyClDeclBinders ats ++ [n | L _ (TypeSig ns _) <- sigs, n <- ns]
hsTyClDeclBinders (L _ (TySynonym {tcdLName = name, tcdTyPats = mb_pats }))
| isJust mb_pats = []
| otherwise = [name]
hsTyClDeclBinders (L _ (TyData {tcdLName = tc_name, tcdCons = cons, tcdTyPats = mb_pats }))
| isJust mb_pats = hsConDeclsBinders cons
| otherwise = tc_name : hsConDeclsBinders cons
hsConDeclsBinders :: (Eq name) => [LConDecl name] -> [Located name]
hsConDeclsBinders cons
= snd (foldl do_one ([], []) cons)
where
do_one (flds_seen, acc) (L _ (ConDecl { con_name = lname, con_details = RecCon flds }))
= (map unLoc new_flds ++ flds_seen, lname : new_flds ++ acc)
where
new_flds = filterOut (\f -> unLoc f `elem` flds_seen)
(map cd_fld_name flds)
do_one (flds_seen, acc) (L _ (ConDecl { con_name = lname }))
= (flds_seen, lname:acc)
\end{code}
Note [Binders in family instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In a type or data family instance declaration, the type
constructor is an *occurrence* not a binding site
type instance T Int = Int -> Int -- No binders
data instance S Bool = S1 | S2 -- Binders are S1,S2
%************************************************************************
%* *
Collecting binders the user did not write
%* *
%************************************************************************
The job of this family of functions is to run through binding sites and find the set of all Names
that were defined "implicitly", without being explicitly written by the user.
The main purpose is to find names introduced by record wildcards so that we can avoid
warning the user when they don't use those names (#4404)
\begin{code}
lStmtsImplicits :: [LStmtLR Name idR] -> NameSet
lStmtsImplicits = hs_lstmts
where
hs_lstmts :: [LStmtLR Name idR] -> NameSet
hs_lstmts = foldr (\stmt rest -> unionNameSets (hs_stmt (unLoc stmt)) rest) emptyNameSet
hs_stmt (BindStmt pat _ _ _) = lPatImplicits pat
hs_stmt (LetStmt binds) = hs_local_binds binds
hs_stmt (ExprStmt {}) = emptyNameSet
hs_stmt (LastStmt {}) = emptyNameSet
hs_stmt (ParStmt xs _ _ _) = hs_lstmts $ concatMap fst xs
hs_stmt (TransStmt { trS_stmts = stmts }) = hs_lstmts stmts
hs_stmt (RecStmt { recS_stmts = ss }) = hs_lstmts ss
hs_local_binds (HsValBinds val_binds) = hsValBindsImplicits val_binds
hs_local_binds (HsIPBinds _) = emptyNameSet
hs_local_binds EmptyLocalBinds = emptyNameSet
hsValBindsImplicits :: HsValBindsLR Name idR -> NameSet
hsValBindsImplicits (ValBindsOut binds _)
= foldr (unionNameSets . lhsBindsImplicits . snd) emptyNameSet binds
hsValBindsImplicits (ValBindsIn binds _)
= lhsBindsImplicits binds
lhsBindsImplicits :: LHsBindsLR Name idR -> NameSet
lhsBindsImplicits = foldBag unionNameSets lhs_bind emptyNameSet
where
lhs_bind (L _ (PatBind { pat_lhs = lpat })) = lPatImplicits lpat
lhs_bind _ = emptyNameSet
lPatImplicits :: LPat Name -> NameSet
lPatImplicits = hs_lpat
where
hs_lpat (L _ pat) = hs_pat pat
hs_lpats = foldr (\pat rest -> hs_lpat pat `unionNameSets` rest) emptyNameSet
hs_pat (LazyPat pat) = hs_lpat pat
hs_pat (BangPat pat) = hs_lpat pat
hs_pat (AsPat _ pat) = hs_lpat pat
hs_pat (ViewPat _ pat _) = hs_lpat pat
hs_pat (ParPat pat) = hs_lpat pat
hs_pat (ListPat pats _) = hs_lpats pats
hs_pat (PArrPat pats _) = hs_lpats pats
hs_pat (TuplePat pats _ _) = hs_lpats pats
hs_pat (SigPatIn pat _) = hs_lpat pat
hs_pat (SigPatOut pat _) = hs_lpat pat
hs_pat (CoPat _ pat _) = hs_pat pat
hs_pat (ConPatIn _ ps) = details ps
hs_pat (ConPatOut {pat_args=ps}) = details ps
hs_pat _ = emptyNameSet
details (PrefixCon ps) = hs_lpats ps
details (RecCon fs) = hs_lpats explicit `unionNameSets` mkNameSet (collectPatsBinders implicit)
where (explicit, implicit) = partitionEithers [if pat_explicit then Left pat else Right pat
| (i, fld) <- [0..] `zip` rec_flds fs
, let pat = hsRecFieldArg fld
pat_explicit = maybe True (i<) (rec_dotdot fs)]
details (InfixCon p1 p2) = hs_lpat p1 `unionNameSets` hs_lpat p2
\end{code}
%************************************************************************
%* *
Collecting type signatures from patterns
%* *
%************************************************************************
\begin{code}
collectSigTysFromPats :: [InPat name] -> [LHsType name]
collectSigTysFromPats pats = foldr collect_sig_lpat [] pats
collectSigTysFromPat :: InPat name -> [LHsType name]
collectSigTysFromPat pat = collect_sig_lpat pat []
collect_sig_lpat :: InPat name -> [LHsType name] -> [LHsType name]
collect_sig_lpat pat acc = collect_sig_pat (unLoc pat) acc
collect_sig_pat :: Pat name -> [LHsType name] -> [LHsType name]
collect_sig_pat (SigPatIn pat ty) acc = collect_sig_lpat pat (ty:acc)
collect_sig_pat (LazyPat pat) acc = collect_sig_lpat pat acc
collect_sig_pat (BangPat pat) acc = collect_sig_lpat pat acc
collect_sig_pat (AsPat _ pat) acc = collect_sig_lpat pat acc
collect_sig_pat (ParPat pat) acc = collect_sig_lpat pat acc
collect_sig_pat (ListPat pats _) acc = foldr collect_sig_lpat acc pats
collect_sig_pat (PArrPat pats _) acc = foldr collect_sig_lpat acc pats
collect_sig_pat (TuplePat pats _ _) acc = foldr collect_sig_lpat acc pats
collect_sig_pat (ConPatIn _ ps) acc = foldr collect_sig_lpat acc (hsConPatArgs ps)
collect_sig_pat _ acc = acc
\end{code}