%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[TcMatches]{Typecheck some @Matches@}
+
+TcMatches: Typecheck some @Matches@
\begin{code}
module TcMatches ( tcMatchesFun, tcGRHSsPat, tcMatchesCase, tcMatchLambda,
- matchCtxt, TcMatchCtxt(..),
- tcStmts, tcDoStmts,
+ TcMatchCtxt(..),
+ tcStmts, tcDoStmts, tcBody,
tcDoStmt, tcMDoStmt, tcGuardStmt
) where
-#include "HsVersions.h"
-
import {-# SOURCE #-} TcExpr( tcSyntaxOp, tcInferRho, tcMonoExpr, tcPolyExpr )
-import HsSyn ( HsExpr(..), LHsExpr, MatchGroup(..),
- Match(..), LMatch, GRHSs(..), GRHS(..),
- Stmt(..), LStmt, HsMatchContext(..), HsStmtContext(..),
- pprMatch, isIrrefutableHsPat, mkHsCoerce,
- pprMatchContext, pprStmtContext,
- noSyntaxExpr, matchGroupArity, pprMatches,
- ExprCoFn )
-
+import HsSyn
import TcRnMonad
-import TcHsType ( tcPatSig, UserTypeCtxt(..) )
-import Inst ( newMethodFromName )
-import TcEnv ( TcId, tcLookupLocalIds, tcLookupId, tcExtendIdEnv,
- tcExtendTyVarEnv2 )
-import TcPat ( PatCtxt(..), tcPats, tcPat )
-import TcMType ( newFlexiTyVarTy, newFlexiTyVarTys )
-import TcType ( TcType, TcRhoType,
- BoxySigmaType, BoxyRhoType,
- mkFunTys, mkFunTy, mkAppTy, mkTyConApp,
- liftedTypeKind )
-import TcBinds ( tcLocalBinds )
-import TcUnify ( boxySplitAppTy, boxySplitTyConApp, boxySplitListTy,
- subFunTys, tcSubExp, withBox )
-import TcSimplify ( bindInstsOfLocalFuns )
-import Name ( Name )
-import TysWiredIn ( stringTy, boolTy, parrTyCon, listTyCon, mkListTy, mkPArrTy )
-import PrelNames ( bindMName, returnMName, mfixName, thenMName, failMName )
-import Id ( idType, mkLocalId )
-import TyCon ( TyCon )
+import Inst
+import TcEnv
+import TcPat
+import TcMType
+import TcType
+import TcBinds
+import TcUnify
+import TcSimplify
+import Name
+import TysWiredIn
+import PrelNames
+import Id
+import TyCon
+import TysPrim
import Outputable
-import SrcLoc ( Located(..), getLoc )
-import ErrUtils ( Message )
+import Util
+import SrcLoc
+import FastString
+
+import Control.Monad
+
+#include "HsVersions.h"
\end{code}
%************************************************************************
same number of arguments before using @tcMatches@ to do the work.
\begin{code}
-tcMatchesFun :: Name
+tcMatchesFun :: Name -> Bool
-> MatchGroup Name
-> BoxyRhoType -- Expected type of function
- -> TcM (ExprCoFn, MatchGroup TcId) -- Returns type of body
+ -> TcM (HsWrapper, MatchGroup TcId) -- Returns type of body
-tcMatchesFun fun_name matches exp_ty
+tcMatchesFun fun_name inf matches exp_ty
= do { -- Check that they all have the same no of arguments
-- Location is in the monad, set the caller so that
-- any inter-equation error messages get some vaguely
tcMatches match_ctxt pat_tys rhs_ty matches
}
where
- doc = ptext SLIT("The equation(s) for") <+> quotes (ppr fun_name)
- <+> ptext SLIT("have") <+> speakNOf n_pats (ptext SLIT("argument"))
+ doc = ptext (sLit "The equation(s) for") <+> quotes (ppr fun_name)
+ <+> ptext (sLit "have") <+> speakNOf n_pats (ptext (sLit "argument"))
n_pats = matchGroupArity matches
- match_ctxt = MC { mc_what = FunRhs fun_name, mc_body = tcPolyExpr }
+ match_ctxt = MC { mc_what = FunRhs fun_name inf, mc_body = tcBody }
\end{code}
@tcMatchesCase@ doesn't do the argument-count check because the
-> TcM (MatchGroup TcId) -- Translated alternatives
tcMatchesCase ctxt scrut_ty matches res_ty
+ | isEmptyMatchGroup matches
+ = -- Allow empty case expressions
+ do { -- Make sure we follow the invariant that res_ty is filled in
+ res_ty' <- refineBoxToTau res_ty
+ ; return (MatchGroup [] (mkFunTys [scrut_ty] res_ty')) }
+
+ | otherwise
= tcMatches ctxt [scrut_ty] res_ty matches
-tcMatchLambda :: MatchGroup Name -> BoxyRhoType -> TcM (ExprCoFn, MatchGroup TcId)
+tcMatchLambda :: MatchGroup Name -> BoxyRhoType -> TcM (HsWrapper, MatchGroup TcId)
tcMatchLambda match res_ty
= subFunTys doc 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 1 $ pprMatches LambdaExpr match),
+ doc = sep [ ptext (sLit "The lambda expression")
+ <+> quotes (pprSetDepth 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") <+> speakNOf n_pats (ptext (sLit "argument"))]
match_ctxt = MC { mc_what = LambdaExpr,
- mc_body = tcPolyExpr }
+ mc_body = tcBody }
\end{code}
@tcGRHSsPat@ typechecks @[GRHSs]@ that occur in a @PatMonoBind@.
\begin{code}
tcGRHSsPat :: GRHSs Name -> BoxyRhoType -> TcM (GRHSs TcId)
+-- Used for pattern bindings
tcGRHSsPat grhss res_ty = tcGRHSs match_ctxt grhss res_ty
where
match_ctxt = MC { mc_what = PatBindRhs,
- mc_body = tcPolyExpr }
+ mc_body = tcBody }
\end{code}
data TcMatchCtxt -- c.f. TcStmtCtxt, also in this module
= MC { mc_what :: HsMatchContext Name, -- What kind of thing this is
- mc_body :: LHsExpr Name -- Type checker for a body of an alternative
- -> BoxyRhoType
+ mc_body :: LHsExpr Name -- Type checker for a body of
+ -- an alternative
+ -> BoxyRhoType
-> TcM (LHsExpr TcId) }
tcMatches ctxt pat_tys rhs_ty (MatchGroup matches _)
- = do { matches' <- mapM (tcMatch ctxt pat_tys rhs_ty) matches
+ = ASSERT( not (null matches) ) -- Ensure that rhs_ty is filled in
+ do { matches' <- mapM (tcMatch ctxt pat_tys rhs_ty) matches
; return (MatchGroup matches' (mkFunTys pat_tys rhs_ty)) }
-------------
= wrapLocM (tc_match ctxt pat_tys rhs_ty) match
where
tc_match ctxt pat_tys rhs_ty match@(Match pats maybe_rhs_sig grhss)
- = addErrCtxt (matchCtxt (mc_what ctxt) match) $
- do { (pats', grhss') <- tcPats LamPat pats pat_tys rhs_ty $
+ = add_match_ctxt match $
+ do { (pats', grhss') <- tcLamPats pats pat_tys rhs_ty $
tc_grhss ctxt maybe_rhs_sig grhss
- ; returnM (Match pats' Nothing grhss') }
+ ; return (Match pats' Nothing grhss') }
tc_grhss ctxt Nothing grhss rhs_ty
= tcGRHSs ctxt grhss rhs_ty -- No result signature
- tc_grhss ctxt (Just res_sig) grhss rhs_ty
- = do { (inner_ty, sig_tvs) <- tcPatSig ResSigCtxt res_sig rhs_ty
- ; tcExtendTyVarEnv2 sig_tvs $
- tcGRHSs ctxt grhss inner_ty }
+ -- Result type sigs are no longer supported
+ tc_grhss _ (Just {}) _ _
+ = panic "tc_ghrss" -- Rejected by renamer
+
+ -- For (\x -> e), tcExpr has already said "In the expresssion \x->e"
+ -- so we don't want to add "In the lambda abstraction \x->e"
+ add_match_ctxt match thing_inside
+ = case mc_what ctxt of
+ LambdaExpr -> thing_inside
+ m_ctxt -> addErrCtxt (pprMatchInCtxt m_ctxt match) thing_inside
-------------
-tcGRHSs :: TcMatchCtxt -> GRHSs Name -> BoxyRhoType -> TcM (GRHSs TcId)
+tcGRHSs :: TcMatchCtxt -> GRHSs Name -> BoxyRhoType
+ -> TcM (GRHSs TcId)
-- Notice that we pass in the full res_ty, so that we get
-- good inference from simple things like
tcGRHSs ctxt (GRHSs grhss binds) res_ty
= do { (binds', grhss') <- tcLocalBinds binds $
- mappM (wrapLocM (tcGRHS ctxt res_ty)) grhss
+ mapM (wrapLocM (tcGRHS ctxt res_ty)) grhss
- ; returnM (GRHSs grhss' binds') }
+ ; return (GRHSs grhss' binds') }
-------------
tcGRHS :: TcMatchCtxt -> BoxyRhoType -> GRHS Name -> TcM (GRHS TcId)
-> BoxyRhoType
-> TcM (HsExpr TcId) -- Returns a HsDo
tcDoStmts ListComp stmts body res_ty
- = do { elt_ty <- boxySplitListTy res_ty
- ; (stmts', body') <- tcStmts ListComp (tcLcStmt listTyCon) stmts elt_ty $
- tcBody (doBodyCtxt ListComp body) body
- ; return (HsDo ListComp stmts' body' (mkListTy elt_ty)) }
+ = do { (elt_ty, coi) <- boxySplitListTy res_ty
+ ; (stmts', body') <- tcStmts ListComp (tcLcStmt listTyCon) stmts
+ elt_ty $
+ tcBody body
+ ; return $ mkHsWrapCoI coi
+ (HsDo ListComp stmts' body' (mkListTy elt_ty)) }
tcDoStmts PArrComp stmts body res_ty
- = do { [elt_ty] <- boxySplitTyConApp parrTyCon res_ty
- ; (stmts', body') <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts elt_ty $
- tcBody (doBodyCtxt PArrComp body) body
- ; return (HsDo PArrComp stmts' body' (mkPArrTy elt_ty)) }
+ = do { (elt_ty, coi) <- boxySplitPArrTy res_ty
+ ; (stmts', body') <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts
+ elt_ty $
+ tcBody body
+ ; return $ mkHsWrapCoI coi
+ (HsDo PArrComp stmts' body' (mkPArrTy elt_ty)) }
tcDoStmts DoExpr stmts body res_ty
- = do { (m_ty, elt_ty) <- boxySplitAppTy res_ty
- ; let res_ty' = mkAppTy m_ty elt_ty -- The boxySplit consumes res_ty
- ; (stmts', body') <- tcStmts DoExpr (tcDoStmt m_ty) stmts res_ty' $
- tcBody (doBodyCtxt DoExpr body) body
- ; return (HsDo DoExpr stmts' body' res_ty') }
+ = do { (stmts', body') <- tcStmts DoExpr tcDoStmt stmts
+ res_ty $
+ tcBody body
+ ; return (HsDo DoExpr stmts' body' res_ty) }
tcDoStmts ctxt@(MDoExpr _) stmts body res_ty
- = do { (m_ty, elt_ty) <- boxySplitAppTy res_ty
+ = do { ((m_ty, elt_ty), coi) <- boxySplitAppTy res_ty
; let res_ty' = mkAppTy m_ty elt_ty -- The boxySplit consumes res_ty
tc_rhs rhs = withBox liftedTypeKind $ \ pat_ty ->
tcMonoExpr rhs (mkAppTy m_ty pat_ty)
- ; (stmts', body') <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts res_ty' $
- tcBody (doBodyCtxt ctxt body) body
+ ; (stmts', body') <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts
+ res_ty' $
+ tcBody body
; let names = [mfixName, bindMName, thenMName, returnMName, failMName]
; insts <- mapM (newMethodFromName DoOrigin m_ty) names
- ; return (HsDo (MDoExpr (names `zip` insts)) stmts' body' res_ty') }
-
-tcDoStmts ctxt stmts body res_ty = pprPanic "tcDoStmts" (pprStmtContext ctxt)
-
-tcBody :: Message -> LHsExpr Name -> BoxyRhoType -> TcM (LHsExpr TcId)
-tcBody ctxt body res_ty
- = -- addErrCtxt ctxt $ -- This context adds little that is useful
- tcPolyExpr body res_ty
+ ; return $
+ mkHsWrapCoI coi
+ (HsDo (MDoExpr (names `zip` insts)) stmts' body' res_ty') }
+
+tcDoStmts ctxt _ _ _ = pprPanic "tcDoStmts" (pprStmtContext ctxt)
+
+tcBody :: LHsExpr Name -> BoxyRhoType -> TcM (LHsExpr TcId)
+tcBody body res_ty
+ = do { traceTc (text "tcBody" <+> ppr res_ty)
+ ; body' <- tcPolyExpr body res_ty
+ ; return body'
+ }
\end{code}
\begin{code}
type TcStmtChecker
- = forall thing. HsStmtContext Name
- -> Stmt Name
- -> BoxyRhoType -- Result type for comprehension
- -> (BoxyRhoType -> TcM thing) -- Checker for what follows the stmt
- -> TcM (Stmt TcId, thing)
-
- -- The incoming BoxyRhoType may be refined by type refinements
- -- before being passed to the thing_inside
+ = forall thing. HsStmtContext Name
+ -> Stmt Name
+ -> BoxyRhoType -- Result type for comprehension
+ -> (BoxyRhoType -> TcM thing) -- Checker for what follows the stmt
+ -> TcM (Stmt TcId, thing)
tcStmts :: HsStmtContext Name
-> TcStmtChecker -- NB: higher-rank type
-- Note the higher-rank type. stmt_chk is applied at different
-- types in the equations for tcStmts
-tcStmts ctxt stmt_chk [] res_ty thing_inside
+tcStmts _ _ [] res_ty thing_inside
= do { thing <- thing_inside res_ty
; return ([], thing) }
tcStmts ctxt stmt_chk (L loc stmt : stmts) res_ty thing_inside
= do { (stmt', (stmts', thing)) <-
setSrcSpan loc $
- addErrCtxt (stmtCtxt ctxt stmt) $
+ addErrCtxt (pprStmtInCtxt ctxt stmt) $
stmt_chk ctxt stmt res_ty $ \ res_ty' ->
popErrCtxt $
tcStmts ctxt stmt_chk stmts res_ty' $
--------------------------------
-- Pattern guards
tcGuardStmt :: TcStmtChecker
-tcGuardStmt ctxt (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) }
-tcGuardStmt ctxt (BindStmt pat rhs _ _) res_ty thing_inside
+tcGuardStmt _ (BindStmt pat rhs _ _) res_ty thing_inside
= do { (rhs', rhs_ty) <- tcInferRho rhs
- ; (pat', thing) <- tcPat LamPat pat rhs_ty res_ty thing_inside
+ ; (pat', thing) <- tcLamPat pat rhs_ty res_ty thing_inside
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
-tcGuardStmt ctxt stmt res_ty thing_inside
+tcGuardStmt _ stmt _ _
= pprPanic "tcGuardStmt: unexpected Stmt" (ppr stmt)
-> TcStmtChecker
-- A generator, pat <- rhs
-tcLcStmt m_tc ctxt (BindStmt pat rhs _ _) res_ty thing_inside
+tcLcStmt m_tc _ (BindStmt pat rhs _ _) res_ty thing_inside
= do { (rhs', pat_ty) <- withBox liftedTypeKind $ \ ty ->
tcMonoExpr rhs (mkTyConApp m_tc [ty])
- ; (pat', thing) <- tcPat LamPat pat pat_ty res_ty thing_inside
+ ; (pat', thing) <- tcLamPat pat pat_ty res_ty thing_inside
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
-- A boolean guard
-tcLcStmt m_tc ctxt (ExprStmt rhs _ _) res_ty thing_inside
+tcLcStmt _ _ (ExprStmt rhs _ _) res_ty thing_inside
= do { rhs' <- tcMonoExpr rhs boolTy
; thing <- thing_inside res_ty
; return (ExprStmt rhs' noSyntaxExpr boolTy, thing) }
; return (ParStmt pairs', thing) }
where
-- loop :: [([LStmt Name], [Name])] -> TcM ([([LStmt TcId], [TcId])], thing)
- loop [] = do { thing <- thing_inside elt_ty -- No refinement from pattern
+ loop [] = do { thing <- thing_inside elt_ty
; return ([], thing) } -- matching in the branches
loop ((stmts, names) : pairs)
= do { (stmts', (ids, pairs', thing))
- <- tcStmts ctxt (tcLcStmt m_tc) stmts elt_ty $ \ elt_ty' ->
+ <- tcStmts 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 stmt elt_ty thing_inside
+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
+ let alphaListTy = mkTyConApp m_tc [alphaTy]
+
+ (usingExpr', maybeByExpr') <-
+ case maybeByExpr of
+ Nothing -> do
+ -- We must validate that usingExpr :: forall a. [a] -> [a]
+ usingExpr' <- tcPolyExpr usingExpr (mkForAllTy alphaTyVar (alphaListTy `mkFunTy` alphaListTy))
+ return (usingExpr', Nothing)
+ Just byExpr -> do
+ -- We must infer a type such that e :: t and then check that usingExpr :: forall a. (a -> t) -> [a] -> [a]
+ (byExpr', tTy) <- tcInferRho byExpr
+ usingExpr' <- tcPolyExpr usingExpr (mkForAllTy alphaTyVar ((alphaTy `mkFunTy` tTy) `mkFunTy` (alphaListTy `mkFunTy` alphaListTy)))
+ return (usingExpr', Just byExpr')
+
+ binders' <- tcLookupLocalIds binders
+ thing <- thing_inside elt_ty'
+
+ return (binders', usingExpr', maybeByExpr', thing)
+
+ return (TransformStmt (stmts', binders') usingExpr' maybeByExpr', thing)
+
+tcLcStmt m_tc ctxt (GroupStmt (stmts, bindersMap) groupByClause) elt_ty thing_inside = do
+ (stmts', (bindersMap', groupByClause', thing)) <-
+ tcStmts (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do
+ let alphaListTy = mkTyConApp m_tc [alphaTy]
+ alphaListListTy = mkTyConApp m_tc [alphaListTy]
+
+ groupByClause' <-
+ case groupByClause of
+ GroupByNothing usingExpr ->
+ -- We must validate that usingExpr :: forall a. [a] -> [[a]]
+ tcPolyExpr usingExpr (mkForAllTy alphaTyVar (alphaListTy `mkFunTy` alphaListListTy)) >>= (return . GroupByNothing)
+ GroupBySomething eitherUsingExpr byExpr -> do
+ -- We must infer a type such that byExpr :: t
+ (byExpr', tTy) <- tcInferRho byExpr
+
+ -- If it exists, we then check that usingExpr :: forall a. (a -> t) -> [a] -> [[a]]
+ let expectedUsingType = mkForAllTy alphaTyVar ((alphaTy `mkFunTy` tTy) `mkFunTy` (alphaListTy `mkFunTy` alphaListListTy))
+ eitherUsingExpr' <-
+ case eitherUsingExpr of
+ Left usingExpr -> (tcPolyExpr usingExpr expectedUsingType) >>= (return . Left)
+ Right usingExpr -> (tcPolyExpr (noLoc usingExpr) expectedUsingType) >>= (return . Right . unLoc)
+ return $ GroupBySomething eitherUsingExpr' byExpr'
+
+ -- Find the IDs and types of all old binders
+ let (oldBinders, newBinders) = unzip bindersMap
+ oldBinders' <- tcLookupLocalIds oldBinders
+
+ -- Ensure that every old binder of type b is linked up with its new binder which should have type [b]
+ let newBinders' = zipWith associateNewBinder oldBinders' newBinders
+
+ -- Type check the thing in the environment with these new binders and return the result
+ thing <- tcExtendIdEnv newBinders' (thing_inside elt_ty')
+ return (zipEqual "tcLcStmt: Old and new binder lists were not of the same length" oldBinders' newBinders', groupByClause', thing)
+
+ return (GroupStmt (stmts', bindersMap') groupByClause', thing)
+ where
+ associateNewBinder :: TcId -> Name -> TcId
+ associateNewBinder oldBinder newBinder = mkLocalId newBinder (mkTyConApp m_tc [idType oldBinder])
+
+tcLcStmt _ _ stmt _ _
= pprPanic "tcLcStmt: unexpected Stmt" (ppr stmt)
-
+
--------------------------------
-- Do-notation
-- The main excitement here is dealing with rebindable syntax
-tcDoStmt :: TcType -- Monad type, m
- -> TcStmtChecker
+tcDoStmt :: TcStmtChecker
-tcDoStmt m_ty ctxt (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
- = do { (rhs', pat_ty) <- withBox liftedTypeKind $ \ pat_ty ->
- tcMonoExpr rhs (mkAppTy m_ty pat_ty)
- -- We should use type *inference* for the RHS computations, becuase of GADTs.
+tcDoStmt _ (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
+ = do { (rhs', rhs_ty) <- tcInferRho rhs
+ -- We should use type *inference* for the RHS computations,
+ -- becuase of GADTs.
-- do { pat <- rhs; <rest> }
-- is rather like
-- case rhs of { pat -> <rest> }
- -- We do inference on rhs, so that information about its type can be refined
- -- when type-checking the pattern.
-
- ; (pat', thing) <- tcPat LamPat pat pat_ty res_ty thing_inside
+ -- We do inference on rhs, so that information about its type
+ -- can be refined when type-checking the pattern.
+
+ -- Deal with rebindable syntax:
+ -- (>>=) :: rhs_ty -> (pat_ty -> new_res_ty) -> res_ty
+ -- This level of generality is needed for using do-notation
+ -- in full generality; see Trac #1537
+ ; ((bind_op', new_res_ty), pat_ty) <-
+ withBox liftedTypeKind $ \ pat_ty ->
+ withBox liftedTypeKind $ \ new_res_ty ->
+ tcSyntaxOp DoOrigin bind_op
+ (mkFunTys [rhs_ty, mkFunTy pat_ty new_res_ty] res_ty)
- -- Deal with rebindable syntax; (>>=) :: m a -> (a -> m b) -> m b
- ; let bind_ty = mkFunTys [mkAppTy m_ty pat_ty,
- mkFunTy pat_ty res_ty] res_ty
- ; bind_op' <- tcSyntaxOp DoOrigin bind_op bind_ty
-- If (but only if) the pattern can fail,
-- typecheck the 'fail' operator
- ; fail_op' <- if isIrrefutableHsPat pat'
+ ; fail_op' <- if isIrrefutableHsPat pat
then return noSyntaxExpr
- else tcSyntaxOp DoOrigin fail_op (mkFunTy stringTy res_ty)
+ else tcSyntaxOp DoOrigin fail_op (mkFunTy stringTy new_res_ty)
+
+ ; (pat', thing) <- tcLamPat pat pat_ty new_res_ty thing_inside
+
; return (BindStmt pat' rhs' bind_op' fail_op', thing) }
-tcDoStmt m_ty ctxt (ExprStmt rhs then_op _) res_ty thing_inside
- = do { -- Deal with rebindable syntax; (>>) :: m a -> m b -> m b
- a_ty <- newFlexiTyVarTy liftedTypeKind
- ; let rhs_ty = mkAppTy m_ty a_ty
- then_ty = mkFunTys [rhs_ty, res_ty] res_ty
- ; then_op' <- tcSyntaxOp DoOrigin then_op then_ty
- ; rhs' <- tcPolyExpr rhs rhs_ty
- ; thing <- thing_inside res_ty
+tcDoStmt _ (ExprStmt rhs then_op _) res_ty thing_inside
+ = do { (rhs', rhs_ty) <- tcInferRho rhs
+
+ -- Deal with rebindable syntax; (>>) :: rhs_ty -> new_res_ty -> res_ty
+ ; (then_op', new_res_ty) <-
+ withBox liftedTypeKind $ \ new_res_ty ->
+ tcSyntaxOp DoOrigin then_op
+ (mkFunTys [rhs_ty, new_res_ty] res_ty)
+
+ ; thing <- thing_inside new_res_ty
; return (ExprStmt rhs' then_op' rhs_ty, thing) }
-tcDoStmt m_ty ctxt stmt res_ty thing_inside
+tcDoStmt ctxt (RecStmt {}) _ _
+ = failWithTc (ptext (sLit "Illegal 'rec' stmt in") <+> pprStmtContext ctxt)
+ -- This case can't be caught in the renamer
+ -- see RnExpr.checkRecStmt
+
+tcDoStmt _ stmt _ _
= pprPanic "tcDoStmt: unexpected Stmt" (ppr stmt)
--------------------------------
tcMDoStmt :: (LHsExpr Name -> TcM (LHsExpr TcId, TcType)) -- RHS inference
-> TcStmtChecker
-tcMDoStmt tc_rhs ctxt (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
+tcMDoStmt tc_rhs _ (BindStmt pat rhs _ _) res_ty thing_inside
= do { (rhs', pat_ty) <- tc_rhs rhs
- ; (pat', thing) <- tcPat LamPat pat pat_ty res_ty thing_inside
+ ; (pat', thing) <- tcLamPat pat pat_ty res_ty thing_inside
; return (BindStmt pat' rhs' noSyntaxExpr noSyntaxExpr, thing) }
-tcMDoStmt tc_rhs ctxt (ExprStmt rhs then_op _) 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) }
; let rec_ids = zipWith mkLocalId recNames rec_tys
; tcExtendIdEnv rec_ids $ do
{ (stmts', (later_ids, rec_rets))
- <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts res_ty $ \ res_ty' ->
+ <- tcStmts ctxt (tcMDoStmt tc_rhs) stmts res_ty $ \ _res_ty' ->
-- ToDo: res_ty not really right
do { rec_rets <- zipWithM tc_ret recNames rec_tys
; later_ids <- tcLookupLocalIds laterNames
= do { poly_id <- tcLookupId rec_name
-- poly_id may have a polymorphic type
-- but mono_ty is just a monomorphic type variable
- ; co_fn <- tcSubExp (idType poly_id) mono_ty
- ; return (mkHsCoerce co_fn (HsVar poly_id)) }
+ ; co_fn <- tcSubExp DoOrigin (idType poly_id) mono_ty
+ ; return (mkHsWrap co_fn (HsVar poly_id)) }
-tcMDoStmt tc_rhs ctxt stmt res_ty thing_inside
+tcMDoStmt _ _ stmt _ _
= pprPanic "tcMDoStmt: unexpected Stmt" (ppr stmt)
\end{code}
checkArgs fun (MatchGroup (match1:matches) _)
| null bad_matches = return ()
| otherwise
- = failWithTc (vcat [ptext SLIT("Equations for") <+> quotes (ppr fun) <+>
- ptext SLIT("have different numbers of arguments"),
+ = failWithTc (vcat [ptext (sLit "Equations for") <+> quotes (ppr fun) <+>
+ ptext (sLit "have different numbers of arguments"),
nest 2 (ppr (getLoc match1)),
nest 2 (ppr (getLoc (head bad_matches)))])
where
args_in_match :: LMatch Name -> Int
args_in_match (L _ (Match pats _ _)) = length pats
+checkArgs _ _ = panic "TcPat.checkArgs" -- Matches always non-empty
\end{code}
-\begin{code}
-matchCtxt ctxt match = hang (ptext SLIT("In") <+> pprMatchContext ctxt <> colon)
- 4 (pprMatch ctxt match)
-
-doBodyCtxt :: HsStmtContext Name -> LHsExpr Name -> SDoc
-doBodyCtxt ctxt body = hang (ptext SLIT("In the result of") <+> pprStmtContext ctxt <> colon)
- 4 (ppr body)
-
-stmtCtxt ctxt stmt = hang (ptext SLIT("In") <+> pprStmtContext ctxt <> colon)
- 4 (ppr stmt)
-\end{code}
projects / ghc-hetmet.git / blobdiff