%
+% (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,
+ tcStmts, tcDoStmts, tcBody,
tcDoStmt, tcMDoStmt, tcGuardStmt
) where
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 TcGadt
+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 Outputable
-import SrcLoc ( Located(..), getLoc )
-import ErrUtils ( Message )
+import SrcLoc
\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
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
tcMatchesCase ctxt scrut_ty matches res_ty
= 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
-- The pprSetDepth makes the abstraction print briefly
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)
-tcGRHSsPat grhss res_ty = tcGRHSs match_ctxt grhss res_ty
+-- Used for pattern bindings
+tcGRHSsPat grhss res_ty = tcGRHSs match_ctxt grhss (emptyRefinement, res_ty)
+ -- emptyRefinement: no refinement in a pattern binding
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
+ -> (Refinement, BoxyRhoType)
-> TcM (LHsExpr TcId) }
tcMatches ctxt pat_tys rhs_ty (MatchGroup matches _)
= 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 ctxt (Just res_sig) grhss (co, rhs_ty)
+ = do { addErr (ptext SLIT("Ignoring (deprecated) result type signature")
+ <+> ppr res_sig)
+ ; tcGRHSs ctxt grhss (co, rhs_ty) }
+
+ -- 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 (matchCtxt m_ctxt match) thing_inside
-------------
-tcGRHSs :: TcMatchCtxt -> GRHSs Name -> BoxyRhoType -> TcM (GRHSs TcId)
+tcGRHSs :: TcMatchCtxt -> GRHSs Name -> (Refinement, BoxyRhoType)
+ -> TcM (GRHSs TcId)
-- Notice that we pass in the full res_ty, so that we get
-- good inference from simple things like
; returnM (GRHSs grhss' binds') }
-------------
-tcGRHS :: TcMatchCtxt -> BoxyRhoType -> GRHS Name -> TcM (GRHS TcId)
+tcGRHS :: TcMatchCtxt -> (Refinement, BoxyRhoType) -> GRHS Name -> TcM (GRHS TcId)
tcGRHS ctxt res_ty (GRHS guards rhs)
= do { (guards', rhs') <- tcStmts stmt_ctxt tcGuardStmt guards res_ty $
-> 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
+ ; (stmts', body') <- tcStmts ListComp (tcLcStmt listTyCon) stmts
+ (emptyRefinement,elt_ty) $
+ tcBody body
; return (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
+ ; (stmts', body') <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts
+ (emptyRefinement, elt_ty) $
+ tcBody body
; return (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
+ ; (stmts', body') <- tcStmts DoExpr (tcDoStmt m_ty) stmts
+ (emptyRefinement, res_ty') $
+ tcBody body
; return (HsDo DoExpr stmts' body' res_ty') }
tcDoStmts ctxt@(MDoExpr _) stmts body 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
+ (emptyRefinement, res_ty') $
+ tcBody body
; let names = [mfixName, bindMName, thenMName, returnMName, failMName]
; insts <- mapM (newMethodFromName DoOrigin m_ty) names
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
+tcBody :: LHsExpr Name -> (Refinement, BoxyRhoType) -> TcM (LHsExpr TcId)
+tcBody body (reft, res_ty)
+ = do { traceTc (text "tcBody" <+> ppr res_ty <+> ppr reft)
+ ; let (co, res_ty') = refineResType reft res_ty
+ ; body' <- tcPolyExpr body res_ty'
+ ; return (mkLHsWrap co 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)
+ = forall thing. HsStmtContext Name
+ -> Stmt Name
+ -> (Refinement, BoxyRhoType) -- Result type for comprehension
+ -> ((Refinement,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
tcStmts :: HsStmtContext Name
-> TcStmtChecker -- NB: higher-rank type
-> [LStmt Name]
- -> BoxyRhoType
- -> (BoxyRhoType -> TcM thing)
+ -> (Refinement, BoxyRhoType)
+ -> ((Refinement, BoxyRhoType) -> TcM thing)
-> TcM ([LStmt TcId], thing)
-- Note the higher-rank type. stmt_chk is applied at different
tcGuardStmt ctxt (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
tcLcStmt m_tc ctxt (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
tcDoStmt :: TcType -- Monad type, m
-> TcStmtChecker
-tcDoStmt m_ty ctxt (BindStmt pat rhs bind_op fail_op) res_ty thing_inside
+tcDoStmt m_ty ctxt (BindStmt pat rhs bind_op fail_op) reft_res_ty@(_,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.
-- 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
+ ; (pat', thing) <- tcLamPat pat pat_ty reft_res_ty thing_inside
-- Deal with rebindable syntax; (>>=) :: m a -> (a -> m b) -> m b
; let bind_ty = mkFunTys [mkAppTy m_ty pat_ty,
; return (BindStmt pat' rhs' bind_op' fail_op', thing) }
-tcDoStmt m_ty ctxt (ExprStmt rhs then_op _) res_ty thing_inside
+tcDoStmt m_ty ctxt (ExprStmt rhs then_op _) reft_res_ty@(_,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
+ ; thing <- thing_inside reft_res_ty
; return (ExprStmt rhs' then_op' rhs_ty, thing) }
tcDoStmt m_ty ctxt stmt res_ty thing_inside
-> TcStmtChecker
tcMDoStmt tc_rhs ctxt (BindStmt pat rhs bind_op fail_op) 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
-- 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)) }
+ ; return (mkHsWrap co_fn (HsVar poly_id)) }
tcMDoStmt tc_rhs ctxt stmt res_ty thing_inside
= pprPanic "tcMDoStmt: unexpected Stmt" (ppr stmt)
args_in_match :: LMatch Name -> Int
args_in_match (L _ (Match pats _ _)) = length pats
+checkArgs fun other = 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