Id typecheck/TcHsSyn
\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 HsUtils where
#include "HsVersions.h"
import HsPat
import HsTypes
import HsLit
-import HsDecls
import RdrName
import Var
+import Coercion
import Type
import DataCon
import Name
mkHsWrap co_fn e | isIdHsWrapper co_fn = e
| otherwise = HsWrap co_fn e
+mkHsWrapCoI :: CoercionI -> HsExpr id -> HsExpr id
+mkHsWrapCoI IdCo e = e
+mkHsWrapCoI (ACo co) e = mkHsWrap (WpCo co) e
+
mkHsLam :: [LPat id] -> LHsExpr id -> LHsExpr id
mkHsLam pats body = mkHsPar (L (getLoc body) (HsLam matches))
where
val_binds = ValBindsOut [(Recursive, binds)] []
mkHsConApp :: DataCon -> [Type] -> [HsExpr Id] -> LHsExpr Id
--- Used for constructing dictinoary terms etc, so no locations
+-- Used for constructing dictionary terms etc, so no locations
mkHsConApp data_con tys args
= foldl mk_app (nlHsTyApp (dataConWrapId data_con) tys) args
where
mkHsIntegral i = HsIntegral i noSyntaxExpr
mkHsFractional f = HsFractional f noSyntaxExpr
+mkHsIsString s = HsIsString s noSyntaxExpr
mkHsDo ctxt stmts body = HsDo ctxt stmts body placeHolderType
-mkNPat lit neg = NPat lit neg noSyntaxExpr placeHolderType
+mkNPat lit neg = NPat lit neg noSyntaxExpr
mkNPlusKPat id lit = NPlusKPat id lit noSyntaxExpr noSyntaxExpr
mkExprStmt expr = ExprStmt expr noSyntaxExpr placeHolderType
nlHsAppTy f t = noLoc (HsAppTy f t)
nlHsTyVar x = noLoc (HsTyVar x)
nlHsFunTy a b = noLoc (HsFunTy a b)
+
+nlHsTyConApp tycon tys = foldl nlHsAppTy (nlHsTyVar tycon) tys
\end{code}
it should return [x, y, f, a, b] (remember, order important).
\begin{code}
-collectLocalBinders :: HsLocalBinds name -> [Located name]
+collectLocalBinders :: HsLocalBindsLR idL idR -> [Located idL]
collectLocalBinders (HsValBinds val_binds) = collectHsValBinders val_binds
collectLocalBinders (HsIPBinds _) = []
collectLocalBinders EmptyLocalBinds = []
-collectHsValBinders :: HsValBinds name -> [Located name]
+collectHsValBinders :: HsValBindsLR idL idR -> [Located idL]
collectHsValBinders (ValBindsIn binds sigs) = collectHsBindLocatedBinders binds
collectHsValBinders (ValBindsOut binds sigs) = foldr collect_one [] binds
where
collect_one (_,binds) acc = foldrBag (collectAcc . unLoc) acc binds
-collectAcc :: HsBind name -> [Located name] -> [Located name]
+collectAcc :: HsBindLR idL idR -> [Located idL] -> [Located idL]
collectAcc (PatBind { pat_lhs = p }) acc = collectLocatedPatBinders p ++ acc
collectAcc (FunBind { fun_id = f }) acc = f : acc
collectAcc (VarBind { var_id = f }) acc = noLoc f : acc
-- The only time we collect binders from a typechecked
-- binding (hence see AbsBinds) is in zonking in TcHsSyn
-collectHsBindBinders :: LHsBinds name -> [name]
+collectHsBindBinders :: LHsBindsLR idL idR -> [idL]
collectHsBindBinders binds = map unLoc (collectHsBindLocatedBinders binds)
-collectHsBindLocatedBinders :: LHsBinds name -> [Located name]
+collectHsBindLocatedBinders :: LHsBindsLR idL idR -> [Located idL]
collectHsBindLocatedBinders binds = foldrBag (collectAcc . unLoc) [] binds
\end{code}
%************************************************************************
\begin{code}
-collectLStmtsBinders :: [LStmt id] -> [Located id]
+collectLStmtsBinders :: [LStmtLR idL idR] -> [Located idL]
collectLStmtsBinders = concatMap collectLStmtBinders
-collectStmtsBinders :: [Stmt id] -> [Located id]
+collectStmtsBinders :: [StmtLR idL idR] -> [Located idL]
collectStmtsBinders = concatMap collectStmtBinders
-collectLStmtBinders :: LStmt id -> [Located id]
+collectLStmtBinders :: LStmtLR idL idR -> [Located idL]
collectLStmtBinders = collectStmtBinders . unLoc
-collectStmtBinders :: Stmt id -> [Located id]
+collectStmtBinders :: StmtLR idL idR -> [Located idL]
-- Id Binders for a Stmt... [but what about pattern-sig type vars]?
collectStmtBinders (BindStmt pat _ _ _) = collectLocatedPatBinders pat
collectStmtBinders (LetStmt binds) = collectLocalBinders binds
-collectStmtBinders (ExprStmt _ _ _) = []
-collectStmtBinders (RecStmt ss _ _ _ _) = collectLStmtsBinders ss
-collectStmtBinders other = panic "collectStmtBinders"
+collectStmtBinders (ExprStmt _ _ _) = []
+collectStmtBinders (ParStmt xs) = collectLStmtsBinders
+ $ concatMap fst xs
+collectStmtBinders (RecStmt ss _ _ _ _) = collectLStmtsBinders ss
\end{code}
go (LazyPat pat) = collectl pat bndrs
go (BangPat pat) = collectl pat bndrs
go (AsPat a pat) = a : collectl pat bndrs
+ go (ViewPat exp pat _) = collectl pat bndrs
go (ParPat pat) = collectl pat bndrs
go (ListPat pats _) = foldr collectl bndrs pats
go (PArrPat pats _) = foldr collectl bndrs pats
go (TuplePat pats _ _) = foldr collectl bndrs pats
- go (ConPatIn c ps) = foldr collectl bndrs (hsConArgs ps)
- go (ConPatOut { pat_dicts = ds,
- pat_binds = bs, pat_args = ps })
- = map noLoc ds
- ++ collectHsBindLocatedBinders bs
- ++ foldr collectl bndrs (hsConArgs ps)
+ go (ConPatIn c ps) = foldr collectl bndrs (hsConPatArgs ps)
+ go (ConPatOut {pat_args=ps}) = foldr collectl bndrs (hsConPatArgs ps)
+ -- See Note [Dictionary binders in ConPatOut]
go (LitPat _) = bndrs
- go (NPat _ _ _ _) = bndrs
+ go (NPat _ _ _) = bndrs
go (NPlusKPat n _ _ _) = n : bndrs
-
+
go (SigPatIn pat _) = collectl pat bndrs
go (SigPatOut pat _) = collectl pat bndrs
go (TypePat ty) = bndrs
- go (DictPat ids1 ids2) = map noLoc ids1 ++ map noLoc ids2
- ++ bndrs
go (CoPat _ pat ty) = collectl (noLoc pat) bndrs
\end{code}
+Note [Dictionary binders in ConPatOut]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+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}
collectSigTysFromPats :: [InPat name] -> [LHsType name]
collectSigTysFromPats pats = foldr collect_lpat [] pats
collect_pat (ListPat pats _) acc = foldr collect_lpat acc pats
collect_pat (PArrPat pats _) acc = foldr collect_lpat acc pats
collect_pat (TuplePat pats _ _) acc = foldr collect_lpat acc pats
-collect_pat (ConPatIn c ps) acc = foldr collect_lpat acc (hsConArgs ps)
+collect_pat (ConPatIn c ps) acc = foldr collect_lpat acc (hsConPatArgs ps)
collect_pat other acc = acc -- Literals, vars, wildcard
\end{code}
-
-%************************************************************************
-%* *
-%* Getting the main binder name of a top declaration
-%* *
-%************************************************************************
-
-\begin{code}
-
-getMainDeclBinder :: HsDecl name -> Maybe name
-getMainDeclBinder (TyClD d) = Just (tcdName d)
-getMainDeclBinder (ValD d)
- = case collectAcc d [] of
- [] -> Nothing -- see rn003
- (name:_) -> Just (unLoc name)
-getMainDeclBinder (SigD d) = sigNameNoLoc d
-getMainDeclBinder (ForD (ForeignImport name _ _)) = Just (unLoc name)
-getMainDeclBinder (ForD (ForeignExport name _ _)) = Just (unLoc name)
-getMainDeclBinder _ = Nothing
-
-\end{code}