\begin{code}
module TcMatches ( tcMatchesFun, tcGRHSsPat, tcMatchesCase, tcMatchLambda,
TcMatchCtxt(..),
- tcStmts, tcDoStmts, tcBody,
+ tcStmts, tcStmtsAndThen, tcDoStmts, tcBody,
tcDoStmt, tcMDoStmt, tcGuardStmt
) where
tcMonoExpr, tcMonoExprNC, tcPolyExpr )
import HsSyn
+import BasicTypes
import TcRnMonad
-import Inst
import TcEnv
import TcPat
import TcMType
import TcUnify
import Name
import TysWiredIn
-import PrelNames
import Id
import TyCon
import TysPrim
import Coercion ( mkSymCoI )
import Outputable
-import VarSet
-import BasicTypes ( Arity )
import Util
import SrcLoc
import FastString
+-- Create chunkified tuple tybes for monad comprehensions
+import MkCore
+
import Control.Monad
#include "HsVersions.h"
; checkArgs fun_name matches
; (wrap_gen, (wrap_fun, group))
- <- tcGen (SigSkol (FunSigCtxt fun_name)) emptyVarSet exp_ty $ \ _ exp_rho ->
+ <- tcGen (FunSigCtxt fun_name) exp_ty $ \ _ exp_rho ->
-- Note [Polymorphic expected type for tcMatchesFun]
matchFunTys herald arity exp_rho $ \ pat_tys rhs_ty ->
tcMatches match_ctxt pat_tys rhs_ty matches
tcMatchLambda :: MatchGroup Name -> TcRhoType -> TcM (HsWrapper, MatchGroup TcId)
tcMatchLambda match res_ty
- = matchFunTys doc n_pats res_ty $ \ pat_tys rhs_ty ->
+ = matchFunTys herald n_pats res_ty $ \ pat_tys rhs_ty ->
tcMatches match_ctxt pat_tys rhs_ty match
where
n_pats = matchGroupArity match
- doc = sep [ ptext (sLit "The lambda expression")
- <+> quotes (pprSetDepth (PartWay 1) $
+ herald = sep [ ptext (sLit "The lambda expression")
+ <+> quotes (pprSetDepth (PartWay 1) $
pprMatches (LambdaExpr :: HsMatchContext Name) match),
-- The pprSetDepth makes the abstraction print briefly
- ptext (sLit "has") <+> speakNOf n_pats (ptext (sLit "argument"))]
+ ptext (sLit "has")]
match_ctxt = MC { mc_what = LambdaExpr,
mc_body = tcBody }
\end{code}
where
tc_match ctxt pat_tys rhs_ty match@(Match pats maybe_rhs_sig grhss)
= add_match_ctxt match $
- do { (pats', grhss') <- tcPats (mc_what ctxt) pats pat_tys rhs_ty $
+ do { (pats', grhss') <- tcPats (mc_what ctxt) pats pat_tys $
tc_grhss ctxt maybe_rhs_sig grhss rhs_ty
; return (Match pats' Nothing grhss') }
tcGRHS :: TcMatchCtxt -> TcRhoType -> GRHS Name -> TcM (GRHS TcId)
tcGRHS ctxt res_ty (GRHS guards rhs)
- = do { (guards', rhs') <- tcStmts stmt_ctxt tcGuardStmt guards res_ty $
+ = do { (guards', rhs') <- tcStmtsAndThen stmt_ctxt tcGuardStmt guards res_ty $
mc_body ctxt rhs
; return (GRHS guards' rhs') }
where
\begin{code}
tcDoStmts :: HsStmtContext Name
-> [LStmt Name]
- -> LHsExpr Name
-> TcRhoType
-> TcM (HsExpr TcId) -- Returns a HsDo
-tcDoStmts ListComp stmts body res_ty
+tcDoStmts ListComp stmts res_ty
= do { (coi, elt_ty) <- matchExpectedListTy res_ty
- ; (stmts', body') <- tcStmts ListComp (tcLcStmt listTyCon) stmts
- elt_ty $
- tcBody body
+ ; stmts' <- tcStmts ListComp (tcLcStmt listTyCon) stmts elt_ty
; return $ mkHsWrapCoI coi
- (HsDo ListComp stmts' body' (mkListTy elt_ty)) }
+ (HsDo ListComp stmts' (mkListTy elt_ty)) }
-tcDoStmts PArrComp stmts body res_ty
+tcDoStmts PArrComp stmts res_ty
= do { (coi, elt_ty) <- matchExpectedPArrTy res_ty
- ; (stmts', body') <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts
- elt_ty $
- tcBody body
+ ; stmts' <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts elt_ty
; return $ mkHsWrapCoI coi
- (HsDo PArrComp stmts' body' (mkPArrTy elt_ty)) }
-
-tcDoStmts DoExpr stmts body res_ty
- = do { (stmts', body') <- tcStmts DoExpr tcDoStmt stmts res_ty $
- tcBody body
- ; return (HsDo DoExpr stmts' body' res_ty) }
+ (HsDo PArrComp stmts' (mkPArrTy elt_ty)) }
-tcDoStmts ctxt@(MDoExpr _) stmts body res_ty
- = do { (coi, (m_ty, elt_ty)) <- matchExpectedAppTy res_ty
- ; let res_ty' = mkAppTy m_ty elt_ty -- The matchExpected consumes res_ty
- tc_rhs rhs = tcInfer $ \ pat_ty ->
- tcMonoExpr rhs (mkAppTy m_ty pat_ty)
+tcDoStmts DoExpr stmts res_ty
+ = do { stmts' <- tcStmts DoExpr tcDoStmt stmts res_ty
+ ; return (HsDo DoExpr stmts' res_ty) }
- ; (stmts', body') <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts res_ty' $
- tcBody body
+tcDoStmts MDoExpr stmts res_ty
+ = do { stmts' <- tcStmts MDoExpr tcDoStmt stmts res_ty
+ ; return (HsDo MDoExpr stmts' res_ty) }
- ; let names = [mfixName, bindMName, thenMName, returnMName, failMName]
- ; insts <- mapM (\name -> newMethodFromName DoOrigin name m_ty) names
- ; return $ mkHsWrapCoI coi $
- HsDo (MDoExpr (names `zip` insts)) stmts' body' res_ty' }
+tcDoStmts MonadComp stmts res_ty
+ = do { stmts' <- tcStmts MonadComp tcMcStmt stmts res_ty
+ ; return (HsDo MonadComp stmts' res_ty) }
-tcDoStmts ctxt _ _ _ = pprPanic "tcDoStmts" (pprStmtContext ctxt)
+tcDoStmts ctxt _ _ = pprPanic "tcDoStmts" (pprStmtContext ctxt)
tcBody :: LHsExpr Name -> TcRhoType -> TcM (LHsExpr TcId)
tcBody body res_ty
-> TcStmtChecker -- NB: higher-rank type
-> [LStmt Name]
-> TcRhoType
- -> (TcRhoType -> TcM thing)
- -> TcM ([LStmt TcId], thing)
+ -> TcM [LStmt TcId]
+tcStmts ctxt stmt_chk stmts res_ty
+ = do { (stmts', _) <- tcStmtsAndThen ctxt stmt_chk stmts res_ty $
+ const (return ())
+ ; return stmts' }
+
+tcStmtsAndThen :: HsStmtContext Name
+ -> TcStmtChecker -- NB: higher-rank type
+ -> [LStmt Name]
+ -> TcRhoType
+ -> (TcRhoType -> TcM thing)
+ -> TcM ([LStmt TcId], thing)
-- Note the higher-rank type. stmt_chk is applied at different
-- types in the equations for tcStmts
-tcStmts _ _ [] res_ty thing_inside
+tcStmtsAndThen _ _ [] res_ty thing_inside
= do { thing <- thing_inside res_ty
; return ([], thing) }
-- LetStmts are handled uniformly, regardless of context
-tcStmts ctxt stmt_chk (L loc (LetStmt binds) : stmts) res_ty thing_inside
+tcStmtsAndThen ctxt stmt_chk (L loc (LetStmt binds) : stmts) res_ty thing_inside
= do { (binds', (stmts',thing)) <- tcLocalBinds binds $
- tcStmts ctxt stmt_chk stmts res_ty thing_inside
+ tcStmtsAndThen ctxt stmt_chk stmts res_ty thing_inside
; return (L loc (LetStmt binds') : stmts', thing) }
-- For the vanilla case, handle the location-setting part
-tcStmts ctxt stmt_chk (L loc stmt : stmts) res_ty thing_inside
+tcStmtsAndThen ctxt stmt_chk (L loc stmt : stmts) res_ty thing_inside
= do { (stmt', (stmts', thing)) <-
- setSrcSpan loc $
- addErrCtxt (pprStmtInCtxt ctxt stmt) $
- stmt_chk ctxt stmt res_ty $ \ res_ty' ->
- popErrCtxt $
- tcStmts ctxt stmt_chk stmts res_ty' $
+ setSrcSpan loc $
+ addErrCtxt (pprStmtInCtxt ctxt stmt) $
+ stmt_chk ctxt stmt res_ty $ \ res_ty' ->
+ popErrCtxt $
+ tcStmtsAndThen ctxt stmt_chk stmts res_ty' $
thing_inside
; return (L loc stmt' : stmts', thing) }
--------------------------------
-- Pattern guards
tcGuardStmt :: TcStmtChecker
-tcGuardStmt _ (ExprStmt guard _ _) res_ty thing_inside
+tcGuardStmt _ (ExprStmt guard _ _ _) res_ty thing_inside
= do { guard' <- tcMonoExpr guard boolTy
; thing <- thing_inside res_ty
- ; return (ExprStmt guard' noSyntaxExpr boolTy, thing) }
+ ; return (ExprStmt guard' noSyntaxExpr noSyntaxExpr boolTy, thing) }
tcGuardStmt ctxt (BindStmt pat rhs _ _) res_ty thing_inside
= do { (rhs', rhs_ty) <- tcInferRhoNC rhs -- Stmt has a context already
- ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat rhs_ty res_ty $
+ ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat rhs_ty $
thing_inside res_ty
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
tcLcStmt :: TyCon -- The list/Parray type constructor ([] or PArray)
-> TcStmtChecker
+tcLcStmt _ _ (LastStmt body _) elt_ty thing_inside
+ = do { body' <- tcMonoExprNC body elt_ty
+ ; thing <- thing_inside (panic "tcLcStmt: thing_inside")
+ ; return (LastStmt body' noSyntaxExpr, thing) }
+
-- A generator, pat <- rhs
-tcLcStmt m_tc ctxt (BindStmt pat rhs _ _) res_ty thing_inside
+tcLcStmt m_tc ctxt (BindStmt pat rhs _ _) elt_ty thing_inside
= do { pat_ty <- newFlexiTyVarTy liftedTypeKind
; rhs' <- tcMonoExpr rhs (mkTyConApp m_tc [pat_ty])
- ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty res_ty $
- thing_inside res_ty
+ ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty $
+ thing_inside elt_ty
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
-- A boolean guard
-tcLcStmt _ _ (ExprStmt rhs _ _) res_ty thing_inside
+tcLcStmt _ _ (ExprStmt rhs _ _ _) elt_ty thing_inside
= do { rhs' <- tcMonoExpr rhs boolTy
- ; thing <- thing_inside res_ty
- ; return (ExprStmt rhs' noSyntaxExpr boolTy, thing) }
+ ; thing <- thing_inside elt_ty
+ ; return (ExprStmt rhs' noSyntaxExpr noSyntaxExpr boolTy, thing) }
-- A parallel set of comprehensions
-- [ (g x, h x) | ... ; let g v = ...
-- So the binders of the first parallel group will be in scope in the second
-- group. But that's fine; there's no shadowing to worry about.
-tcLcStmt m_tc ctxt (ParStmt bndr_stmts_s) elt_ty thing_inside
+tcLcStmt m_tc ctxt (ParStmt bndr_stmts_s _ _ _) elt_ty thing_inside
= do { (pairs', thing) <- loop bndr_stmts_s
- ; return (ParStmt pairs', thing) }
+ ; return (ParStmt pairs' noSyntaxExpr noSyntaxExpr noSyntaxExpr, thing) }
where
-- loop :: [([LStmt Name], [Name])] -> TcM ([([LStmt TcId], [TcId])], thing)
loop [] = do { thing <- thing_inside elt_ty
loop ((stmts, names) : pairs)
= do { (stmts', (ids, pairs', thing))
- <- tcStmts ctxt (tcLcStmt m_tc) stmts elt_ty $ \ _elt_ty' ->
+ <- tcStmtsAndThen ctxt (tcLcStmt m_tc) stmts elt_ty $ \ _elt_ty' ->
do { ids <- tcLookupLocalIds names
; (pairs', thing) <- loop pairs
; return (ids, pairs', thing) }
; return ( (stmts', ids) : pairs', thing ) }
-tcLcStmt m_tc ctxt (TransformStmt stmts binders usingExpr maybeByExpr) elt_ty thing_inside = do
+tcLcStmt m_tc ctxt (TransformStmt stmts binders usingExpr maybeByExpr _ _) elt_ty thing_inside = do
(stmts', (binders', usingExpr', maybeByExpr', thing)) <-
- tcStmts (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do
+ tcStmtsAndThen (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do
let alphaListTy = mkTyConApp m_tc [alphaTy]
(usingExpr', maybeByExpr') <-
return (binders', usingExpr', maybeByExpr', thing)
- return (TransformStmt stmts' binders' usingExpr' maybeByExpr', thing)
+ return (TransformStmt stmts' binders' usingExpr' maybeByExpr' noSyntaxExpr noSyntaxExpr, thing)
-tcLcStmt m_tc ctxt (GroupStmt stmts bindersMap by using) elt_ty thing_inside
+tcLcStmt m_tc ctxt (GroupStmt { grpS_stmts = stmts, grpS_bndrs = bindersMap
+ , grpS_by = by, grpS_using = using
+ , grpS_explicit = explicit }) elt_ty thing_inside
= do { let (bndr_names, list_bndr_names) = unzip bindersMap
; (stmts', (bndr_ids, by', using_ty, elt_ty')) <-
- tcStmts (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do
+ tcStmtsAndThen (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do
(by', using_ty) <-
case by of
Nothing -> -- check that using :: forall a. [a] -> [[a]]
bindersMap' = bndr_ids `zip` list_bndr_ids
-- See Note [GroupStmt binder map] in HsExpr
- ; using' <- case using of
- Left e -> do { e' <- tcPolyExpr e using_ty; return (Left e') }
- Right e -> do { e' <- tcPolyExpr (noLoc e) using_ty; return (Right (unLoc e')) }
+ ; using' <- tcPolyExpr using using_ty
-- Type check the thing in the environment with
-- these new binders and return the result
; thing <- tcExtendIdEnv list_bndr_ids (thing_inside elt_ty')
- ; return (GroupStmt stmts' bindersMap' by' using', thing) }
+ ; return (emptyGroupStmt { grpS_stmts = stmts', grpS_bndrs = bindersMap'
+ , grpS_by = by', grpS_using = using'
+ , grpS_explicit = explicit }, thing) }
where
alphaListTy = mkTyConApp m_tc [alphaTy]
alphaListListTy = mkTyConApp m_tc [alphaListTy]
tcLcStmt _ _ stmt _ _
= pprPanic "tcLcStmt: unexpected Stmt" (ppr stmt)
+
+--------------------------------
+-- Monad comprehensions
+
+tcMcStmt :: TcStmtChecker
+
+tcMcStmt _ (LastStmt body return_op) res_ty thing_inside
+ = do { a_ty <- newFlexiTyVarTy liftedTypeKind
+ ; return_op' <- tcSyntaxOp MCompOrigin return_op
+ (a_ty `mkFunTy` res_ty)
+ ; body' <- tcMonoExprNC body a_ty
+ ; thing <- thing_inside (panic "tcMcStmt: thing_inside")
+ ; return (LastStmt body' return_op', thing) }
+
+-- Generators for monad comprehensions ( pat <- rhs )
+--
+-- [ body | q <- gen ] -> gen :: m a
+-- q :: a
+--
+
+tcMcStmt ctxt (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
+ = do { rhs_ty <- newFlexiTyVarTy liftedTypeKind
+ ; pat_ty <- newFlexiTyVarTy liftedTypeKind
+ ; new_res_ty <- newFlexiTyVarTy liftedTypeKind
+
+ -- (>>=) :: rhs_ty -> (pat_ty -> new_res_ty) -> res_ty
+ ; bind_op' <- tcSyntaxOp MCompOrigin bind_op
+ (mkFunTys [rhs_ty, mkFunTy pat_ty new_res_ty] res_ty)
+
+ -- If (but only if) the pattern can fail, typecheck the 'fail' operator
+ ; fail_op' <- if isIrrefutableHsPat pat
+ then return noSyntaxExpr
+ else tcSyntaxOp MCompOrigin fail_op (mkFunTy stringTy new_res_ty)
+
+ ; rhs' <- tcMonoExprNC rhs rhs_ty
+ ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty $
+ thing_inside new_res_ty
+
+ ; return (BindStmt pat' rhs' bind_op' fail_op', thing) }
+
+-- Boolean expressions.
+--
+-- [ body | stmts, expr ] -> expr :: m Bool
+--
+tcMcStmt _ (ExprStmt rhs then_op guard_op _) res_ty thing_inside
+ = do { -- Deal with rebindable syntax:
+ -- guard_op :: test_ty -> rhs_ty
+ -- then_op :: rhs_ty -> new_res_ty -> res_ty
+ -- Where test_ty is, for example, Bool
+ test_ty <- newFlexiTyVarTy liftedTypeKind
+ ; rhs_ty <- newFlexiTyVarTy liftedTypeKind
+ ; new_res_ty <- newFlexiTyVarTy liftedTypeKind
+ ; rhs' <- tcMonoExpr rhs test_ty
+ ; guard_op' <- tcSyntaxOp MCompOrigin guard_op
+ (mkFunTy test_ty rhs_ty)
+ ; then_op' <- tcSyntaxOp MCompOrigin then_op
+ (mkFunTys [rhs_ty, new_res_ty] res_ty)
+ ; thing <- thing_inside new_res_ty
+ ; return (ExprStmt rhs' then_op' guard_op' rhs_ty, thing) }
+
+-- Transform statements.
+--
+-- [ body | stmts, then f ] -> f :: forall a. m a -> m a
+-- [ body | stmts, then f by e ] -> f :: forall a. (a -> t) -> m a -> m a
+--
+tcMcStmt ctxt (TransformStmt stmts binders usingExpr maybeByExpr return_op bind_op) res_ty thing_inside
+ = do { let star_star_kind = liftedTypeKind `mkArrowKind` liftedTypeKind
+ ; m1_ty <- newFlexiTyVarTy star_star_kind
+ ; m2_ty <- newFlexiTyVarTy star_star_kind
+ ; n_ty <- newFlexiTyVarTy star_star_kind
+ ; tup_ty_var <- newFlexiTyVarTy liftedTypeKind
+ ; new_res_ty <- newFlexiTyVarTy liftedTypeKind
+ ; let m1_tup_ty = m1_ty `mkAppTy` tup_ty_var
+
+ -- 'stmts' returns a result of type (m1_ty tuple_ty),
+ -- typically something like [(Int,Bool,Int)]
+ -- We don't know what tuple_ty is yet, so we use a variable
+ ; (stmts', (binders', usingExpr', maybeByExpr', return_op', bind_op', thing)) <-
+ tcStmtsAndThen (TransformStmtCtxt ctxt) tcMcStmt stmts m1_tup_ty $ \res_ty' -> do
+ { (usingExpr', maybeByExpr') <-
+ case maybeByExpr of
+ Nothing -> do
+ -- We must validate that usingExpr :: forall a. m a -> m a
+ let using_ty = mkForAllTy alphaTyVar $
+ (m_ty `mkAppTy` alphaTy)
+ `mkFunTy`
+ (m_ty `mkAppTy` alphaTy)
+ usingExpr' <- tcPolyExpr usingExpr using_ty
+ return (usingExpr', Nothing)
+ Just byExpr -> do
+ -- We must infer a type such that e :: t and then check that
+ -- usingExpr :: forall a. (a -> t) -> m a -> m a
+ (byExpr', tTy) <- tcInferRhoNC byExpr
+ let using_ty = mkForAllTy alphaTyVar $
+ (alphaTy `mkFunTy` tTy)
+ `mkFunTy`
+ (m_ty `mkAppTy` alphaTy)
+ `mkFunTy`
+ (m_ty `mkAppTy` alphaTy)
+ usingExpr' <- tcPolyExpr usingExpr using_ty
+ return (usingExpr', Just byExpr')
+
+ ; bndr_ids <- tcLookupLocalIds binders
+
+ -- `return` and `>>=` are used to pass around/modify our
+ -- binders, so we know their types:
+ --
+ -- return :: (a,b,c,..) -> m (a,b,c,..)
+ -- (>>=) :: m (a,b,c,..)
+ -- -> ( (a,b,c,..) -> m (a,b,c,..) )
+ -- -> m (a,b,c,..)
+ --
+ ; let bndr_ty = mkBigCoreVarTupTy bndr_ids
+ m_bndr_ty = m_ty `mkAppTy` bndr_ty
+
+ ; return_op' <- tcSyntaxOp MCompOrigin return_op
+ (bndr_ty `mkFunTy` m_bndr_ty)
+
+ ; bind_op' <- tcSyntaxOp MCompOrigin bind_op $
+ m_bndr_ty `mkFunTy` (bndr_ty `mkFunTy` res_ty)
+ `mkFunTy` res_ty
+
+ -- Unify types of the inner comprehension and the binders type
+ ; _ <- unifyType res_ty' m_bndr_ty
+
+ -- Typecheck the `thing` with out old type (which is the type
+ -- of the final result of our comprehension)
+ ; thing <- thing_inside res_ty
+
+ ; return (bndr_ids, usingExpr', maybeByExpr', return_op', bind_op', thing) }
+
+ ; return (TransformStmt stmts' binders' usingExpr' maybeByExpr' return_op' bind_op', thing) }
+
+-- Grouping statements
+--
+-- [ body | stmts, then group by e ]
+-- -> e :: t
+-- [ body | stmts, then group by e using f ]
+-- -> e :: t
+-- f :: forall a. (a -> t) -> m a -> m (m a)
+-- [ body | stmts, then group using f ]
+-- -> f :: forall a. m a -> m (m a)
+--
+tcMcStmt ctxt (GroupStmt { grpS_stmts = stmts, grpS_bndrs = bindersMap
+ , grpS_by = by, grpS_using = using, grpS_explicit = explicit
+ , grpS_ret = return_op, grpS_bind = bind_op
+ , grpS_fmap = fmap_op }) res_ty thing_inside
+ = do { let star_star_kind = liftedTypeKind `mkArrowKind` liftedTypeKind
+ ; m1_ty <- newFlexiTyVarTy star_star_kind
+ ; m2_ty <- newFlexiTyVarTy star_star_kind
+ ; n_ty <- newFlexiTyVarTy star_star_kind
+ ; tup_ty_var <- newFlexiTyVarTy liftedTypeKind
+ ; new_res_ty <- newFlexiTyVarTy liftedTypeKind
+ ; let (bndr_names, n_bndr_names) = unzip bindersMap
+ m1_tup_ty = m1_ty `mkAppTy` tup_ty_var
+
+ -- 'stmts' returns a result of type (m1_ty tuple_ty),
+ -- typically something like [(Int,Bool,Int)]
+ -- We don't know what tuple_ty is yet, so we use a variable
+ ; (stmts', (bndr_ids, by_e_ty, return_op')) <-
+ tcStmtsAndThen (TransformStmtCtxt ctxt) tcMcStmt stmts m1_tup_ty $ \res_ty' -> do
+ { by_e_ty <- case by of
+ Nothing -> return Nothing
+ Just e -> do { e_ty <- tcInferRhoNC e; return (Just e_ty) }
+
+ -- Find the Ids (and hence types) of all old binders
+ ; bndr_ids <- tcLookupLocalIds bndr_names
+
+ -- 'return' is only used for the binders, so we know its type.
+ --
+ -- return :: (a,b,c,..) -> m (a,b,c,..)
+ ; return_op' <- tcSyntaxOp MCompOrigin return_op $
+ (mkBigCoreVarTupTy bndr_ids) `mkFunTy` res_ty'
+
+ ; return (bndr_ids, by_e_ty, return_op') }
+
+
+
+ ; let tup_ty = mkBigCoreVarTupTy bndr_ids -- (a,b,c)
+ using_arg_ty = m1_ty `mkAppTy` tup_ty -- m1 (a,b,c)
+ n_tup_ty = n_ty `mkAppTy` tup_ty -- n (a,b,c)
+ using_res_ty = m2_ty `mkAppTy` n_tup_ty -- m2 (n (a,b,c))
+ using_fun_ty = using_arg_ty `mkFunTy` using_arg_ty
+
+ -- (>>=) :: m2 (n (a,b,c)) -> ( n (a,b,c) -> new_res_ty ) -> res_ty
+ -- using :: ((a,b,c)->t) -> m1 (a,b,c) -> m2 (n (a,b,c))
+
+ --------------- Typecheck the 'bind' function -------------
+ ; bind_op' <- tcSyntaxOp MCompOrigin bind_op $
+ using_res_ty `mkFunTy` (n_tup_ty `mkFunTy` new_res_ty)
+ `mkFunTy` res_ty
+
+ --------------- Typecheck the 'using' function -------------
+ ; let poly_fun_ty = (m1_ty `mkAppTy` alphaTy) `mkFunTy`
+ (m2_ty `mkAppTy` (n_ty `mkAppTy` alphaTy))
+ using_poly_ty = case by_e_ty of
+ Nothing -> mkForAllTy alphaTyVar poly_fun_ty
+ -- using :: forall a. m1 a -> m2 (n a)
+
+ Just (_,t_ty) -> mkForAllTy alphaTyVar $
+ (alphaTy `mkFunTy` t_ty) `mkFunTy` poly_fun_ty
+ -- using :: forall a. (a->t) -> m1 a -> m2 (n a)
+ -- where by :: t
+
+ ; using' <- tcPolyExpr using using_poly_ty
+ ; coi <- unifyType (applyTy using_poly_ty tup_ty)
+ (case by_e_ty of
+ Nothing -> using_fun_ty
+ Just (_,t_ty) -> (tup_ty `mkFunTy` t_ty) `mkFunTy` using_fun_ty)
+ ; let final_using = fmap (mkHsWrapCoI coi . HsWrap (WpTyApp tup_ty)) using'
+
+ --------------- Typecheck the 'fmap' function -------------
+ ; fmap_op' <- fmap unLoc . tcPolyExpr (noLoc fmap_op) $
+ mkForAllTy alphaTyVar $ mkForAllTy betaTyVar $
+ (alphaTy `mkFunTy` betaTy)
+ `mkFunTy` (n_ty `mkAppTy` alphaTy)
+ `mkFunTy` (n_ty `mkAppTy` betaTy)
+
+ ; let mk_n_bndr :: Name -> TcId -> TcId
+ mk_n_bndr n_bndr_name bndr_id
+ = mkLocalId n_bndr_name (n_ty `mkAppTy` idType bndr_id)
+
+ -- Ensure that every old binder of type `b` is linked up with its
+ -- new binder which should have type `n b`
+ -- See Note [GroupStmt binder map] in HsExpr
+ n_bndr_ids = zipWith mk_n_bndr n_bndr_names bndr_ids
+ bindersMap' = bndr_ids `zip` n_bndr_ids
+
+ -- Type check the thing in the environment with these new binders and
+ -- return the result
+ ; thing <- tcExtendIdEnv n_bndr_ids (thing_inside res_ty)
+
+ ; return (GroupStmt { grpS_stmts = stmts', grpS_bndrs = bindersMap'
+ , grpS_by = fmap fst by_e_ty, grpS_using = final_using
+ , grpS_ret = return_op', grpS_bind = bind_op'
+ , grpS_fmap = fmap_op', grpS_explicit = explicit }, thing) }
+
+-- Typecheck `ParStmt`. See `tcLcStmt` for more informations about typechecking
+-- of `ParStmt`s.
+--
+-- Note: The `mzip` function will get typechecked via:
+--
+-- ParStmt [st1::t1, st2::t2, st3::t3]
+--
+-- mzip :: m st1
+-- -> (m st2 -> m st3 -> m (st2, st3)) -- recursive call
+-- -> m (st1, (st2, st3))
+--
+tcMcStmt ctxt (ParStmt bndr_stmts_s mzip_op bind_op return_op) res_ty thing_inside
+ = do { (_,(m_ty,_)) <- matchExpectedAppTy res_ty
+ -- ToDo: what if the coercion isn't the identity?
+
+ ; (pairs', thing) <- loop m_ty bndr_stmts_s
+
+ ; let mzip_ty = mkForAllTys [alphaTyVar, betaTyVar] $
+ (m_ty `mkAppTy` alphaTy)
+ `mkFunTy`
+ (m_ty `mkAppTy` betaTy)
+ `mkFunTy`
+ (m_ty `mkAppTy` mkBoxedTupleTy [alphaTy, betaTy])
+ ; mzip_op' <- unLoc `fmap` tcPolyExpr (noLoc mzip_op) mzip_ty
+
+ -- Typecheck bind:
+ ; let tys = map (mkBigCoreVarTupTy . snd) pairs'
+ tuple_ty = mk_tuple_ty tys
+
+ ; bind_op' <- tcSyntaxOp MCompOrigin bind_op $
+ (m_ty `mkAppTy` tuple_ty)
+ `mkFunTy`
+ (tuple_ty `mkFunTy` res_ty)
+ `mkFunTy`
+ res_ty
+
+ ; return_op' <- fmap unLoc . tcPolyExpr (noLoc return_op) $
+ mkForAllTy alphaTyVar $
+ alphaTy `mkFunTy` (m_ty `mkAppTy` alphaTy)
+
+ ; return (ParStmt pairs' mzip_op' bind_op' return_op', thing) }
+
+ where mk_tuple_ty tys = foldr1 (\tn tm -> mkBoxedTupleTy [tn, tm]) tys
+
+ -- loop :: Type -- m_ty
+ -- -> [([LStmt Name], [Name])]
+ -- -> TcM ([([LStmt TcId], [TcId])], thing)
+ loop _ [] = do { thing <- thing_inside res_ty
+ ; return ([], thing) } -- matching in the branches
+
+ loop m_ty ((stmts, names) : pairs)
+ = do { -- type dummy since we don't know all binder types yet
+ ty_dummy <- newFlexiTyVarTy liftedTypeKind
+ ; (stmts', (ids, pairs', thing))
+ <- tcStmtsAndThen ctxt tcMcStmt stmts ty_dummy $ \res_ty' ->
+ do { ids <- tcLookupLocalIds names
+ ; _ <- unifyType res_ty' (m_ty `mkAppTy` mkBigCoreVarTupTy ids)
+ ; (pairs', thing) <- loop m_ty pairs
+ ; return (ids, pairs', thing) }
+ ; return ( (stmts', ids) : pairs', thing ) }
+
+tcMcStmt _ stmt _ _
+ = pprPanic "tcMcStmt: unexpected Stmt" (ppr stmt)
+
--------------------------------
-- Do-notation
-- The main excitement here is dealing with rebindable syntax
tcDoStmt :: TcStmtChecker
+tcDoStmt _ (LastStmt body _) res_ty thing_inside
+ = do { body' <- tcMonoExprNC body res_ty
+ ; thing <- thing_inside (panic "tcDoStmt: thing_inside")
+ ; return (LastStmt body' noSyntaxExpr, thing) }
+
tcDoStmt ctxt (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
= do { -- Deal with rebindable syntax:
-- (>>=) :: rhs_ty -> (pat_ty -> new_res_ty) -> res_ty
else tcSyntaxOp DoOrigin fail_op (mkFunTy stringTy new_res_ty)
; rhs' <- tcMonoExprNC rhs rhs_ty
- ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty new_res_ty $
+ ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty $
thing_inside new_res_ty
; return (BindStmt pat' rhs' bind_op' fail_op', thing) }
-tcDoStmt _ (ExprStmt rhs then_op _) res_ty thing_inside
+tcDoStmt _ (ExprStmt rhs then_op _ _) res_ty thing_inside
= do { -- Deal with rebindable syntax;
-- (>>) :: rhs_ty -> new_res_ty -> res_ty
-- See also Note [Treat rebindable syntax first]
; rhs' <- tcMonoExprNC rhs rhs_ty
; thing <- thing_inside new_res_ty
- ; return (ExprStmt rhs' then_op' rhs_ty, thing) }
+ ; return (ExprStmt rhs' then_op' noSyntaxExpr rhs_ty, thing) }
tcDoStmt ctxt (RecStmt { recS_stmts = stmts, recS_later_ids = later_names
, recS_rec_ids = rec_names, recS_ret_fn = ret_op
; tcExtendIdEnv tup_ids $ do
{ stmts_ty <- newFlexiTyVarTy liftedTypeKind
; (stmts', (ret_op', tup_rets))
- <- tcStmts ctxt tcDoStmt stmts stmts_ty $ \ inner_res_ty ->
+ <- tcStmtsAndThen ctxt tcDoStmt stmts stmts_ty $ \ inner_res_ty ->
do { tup_rets <- zipWithM tcCheckId tup_names tup_elt_tys
-- Unify the types of the "final" Ids (which may
-- be polymorphic) with those of "knot-tied" Ids
; return (RecStmt { recS_stmts = stmts', recS_later_ids = later_ids
, recS_rec_ids = rec_ids, recS_ret_fn = ret_op'
, recS_mfix_fn = mfix_op', recS_bind_fn = bind_op'
- , recS_rec_rets = tup_rets, recS_dicts = emptyTcEvBinds }, thing)
+ , recS_rec_rets = tup_rets, recS_ret_ty = stmts_ty }, thing)
}}
tcDoStmt _ stmt _ _
tcMDoStmt :: (LHsExpr Name -> TcM (LHsExpr TcId, TcType)) -- RHS inference
-> TcStmtChecker
+-- Used only by TcArrows... should be gotten rid of
tcMDoStmt tc_rhs ctxt (BindStmt pat rhs _ _) res_ty thing_inside
= do { (rhs', pat_ty) <- tc_rhs rhs
- ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty res_ty $
+ ; (pat', thing) <- tcPat (StmtCtxt ctxt) pat pat_ty $
thing_inside res_ty
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
-tcMDoStmt tc_rhs _ (ExprStmt rhs _ _) res_ty thing_inside
+tcMDoStmt tc_rhs _ (ExprStmt rhs _ _ _) res_ty thing_inside
= do { (rhs', elt_ty) <- tc_rhs rhs
; thing <- thing_inside res_ty
- ; return (ExprStmt rhs' noSyntaxExpr elt_ty, thing) }
+ ; return (ExprStmt rhs' noSyntaxExpr noSyntaxExpr elt_ty, thing) }
-tcMDoStmt tc_rhs ctxt (RecStmt stmts laterNames recNames _ _ _ _ _) res_ty thing_inside
+tcMDoStmt tc_rhs ctxt (RecStmt { recS_stmts = stmts, recS_later_ids = laterNames
+ , recS_rec_ids = recNames }) res_ty thing_inside
= do { rec_tys <- newFlexiTyVarTys (length recNames) liftedTypeKind
; let rec_ids = zipWith mkLocalId recNames rec_tys
- ; tcExtendIdEnv rec_ids $ do
+ ; tcExtendIdEnv rec_ids $ do
{ (stmts', (later_ids, rec_rets))
- <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts res_ty $ \ _res_ty' ->
+ <- tcStmtsAndThen ctxt (tcMDoStmt tc_rhs) stmts res_ty $ \ _res_ty' ->
-- ToDo: res_ty not really right
do { rec_rets <- zipWithM tcCheckId recNames rec_tys
; later_ids <- tcLookupLocalIds laterNames
-- some of them with polymorphic things with the same Name
-- (see note [RecStmt] in HsExpr)
--- Need the bindLocalMethods if we re-add Method constraints
--- ; lie_binds <- bindLocalMethods lie later_ids
- ; let lie_binds = emptyTcEvBinds
-
- ; return (RecStmt stmts' later_ids rec_ids noSyntaxExpr noSyntaxExpr noSyntaxExpr rec_rets lie_binds, thing)
+ ; return (emptyRecStmt { recS_stmts = stmts', recS_later_ids = later_ids
+ , recS_rec_ids = rec_ids, recS_rec_rets = rec_rets
+ , recS_ret_ty = res_ty }, thing)
}}
tcMDoStmt _ _ stmt _ _
projects / ghc-hetmet.git / blobdiff