TcMatches: Typecheck some @Matches@
\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 TcMatches ( tcMatchesFun, tcGRHSsPat, tcMatchesCase, tcMatchLambda,
matchCtxt, TcMatchCtxt(..),
tcStmts, tcDoStmts, tcBody,
where
n_pats = matchGroupArity match
doc = sep [ ptext SLIT("The lambda expression")
- <+> quotes (pprSetDepth 1 $ pprMatches LambdaExpr match),
+ <+> quotes (pprSetDepth 1 $ pprMatches (LambdaExpr :: HsMatchContext Name) match),
-- The pprSetDepth makes the abstraction print briefly
ptext SLIT("has") <+> speakNOf n_pats (ptext SLIT("argument"))]
match_ctxt = MC { mc_what = LambdaExpr,
-> BoxyRhoType
-> TcM (HsExpr TcId) -- Returns a HsDo
tcDoStmts ListComp stmts body res_ty
- = do { elt_ty <- boxySplitListTy res_ty
+ = do { (elt_ty, coi) <- boxySplitListTy res_ty
; (stmts', body') <- tcStmts ListComp (tcLcStmt listTyCon) stmts
(emptyRefinement,elt_ty) $
tcBody body
- ; return (HsDo ListComp stmts' body' (mkListTy elt_ty)) }
+ ; return $ mkHsWrapCoI coi
+ (HsDo ListComp stmts' body' (mkListTy elt_ty)) }
tcDoStmts PArrComp stmts body res_ty
- = do { [elt_ty] <- boxySplitTyConApp parrTyCon res_ty
+ = do { (elt_ty, coi) <- boxySplitPArrTy res_ty
; (stmts', body') <- tcStmts PArrComp (tcLcStmt parrTyCon) stmts
(emptyRefinement, elt_ty) $
tcBody body
- ; return (HsDo PArrComp stmts' body' (mkPArrTy elt_ty)) }
+ ; 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
- (emptyRefinement, res_ty') $
+ = do { (stmts', body') <- tcStmts DoExpr tcDoStmt stmts
+ (emptyRefinement, res_ty) $
tcBody body
- ; return (HsDo DoExpr stmts' body' res_ty') }
+ ; 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)
; let names = [mfixName, bindMName, thenMName, returnMName, failMName]
; insts <- mapM (newMethodFromName DoOrigin m_ty) names
- ; return (HsDo (MDoExpr (names `zip` insts)) stmts' body' res_ty') }
+ ; return $
+ mkHsWrapCoI coi
+ (HsDo (MDoExpr (names `zip` insts)) stmts' body' res_ty') }
tcDoStmts ctxt stmts body res_ty = pprPanic "tcDoStmts" (pprStmtContext ctxt)
-- 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) reft_res_ty@(_,res_ty) thing_inside
- = do { (rhs', pat_ty) <- withBox liftedTypeKind $ \ pat_ty ->
- tcMonoExpr rhs (mkAppTy m_ty pat_ty)
+tcDoStmt ctxt (BindStmt pat rhs bind_op fail_op) reft_res_ty@(_,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
-- We do inference on rhs, so that information about its type can be refined
-- when type-checking the pattern.
- ; (pat', thing) <- tcLamPat pat pat_ty reft_res_ty thing_inside
+ -- Deal with rebindable syntax; (>>=) :: rhs_ty -> (a -> res_ty) -> res_ty
+ ; (bind_op', pat_ty) <-
+ withBox liftedTypeKind $ \ pat_ty ->
+ tcSyntaxOp DoOrigin bind_op
+ (mkFunTys [rhs_ty, mkFunTy pat_ty 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)
+
+ ; (pat', thing) <- tcLamPat pat pat_ty reft_res_ty thing_inside
+
; return (BindStmt pat' rhs' bind_op' fail_op', thing) }
-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
+tcDoStmt ctxt (ExprStmt rhs then_op _) reft_res_ty@(_,res_ty) thing_inside
+ = do { (rhs', rhs_ty) <- tcInferRho rhs
+
+ -- Deal with rebindable syntax; (>>) :: rhs_ty -> res_ty -> res_ty
+ ; then_op' <- tcSyntaxOp DoOrigin then_op
+ (mkFunTys [rhs_ty, res_ty] 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
+tcDoStmt ctxt stmt res_ty thing_inside
= pprPanic "tcDoStmt: unexpected Stmt" (ppr stmt)
--------------------------------
= 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
+ ; 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