Typecheck arrow notation
\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 TcArrows ( tcProc ) where
-#include "HsVersions.h"
-
import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho )
import HsSyn
-import TcHsSyn
-
import TcMatches
-
import TcType
import TcMType
import TcBinds
-import TcSimplify
import TcPat
import TcUnify
import TcRnMonad
import TysWiredIn
import VarSet
import TysPrim
-import Type
import SrcLoc
import Outputable
\begin{code}
tcProc :: InPat Name -> LHsCmdTop Name -- proc pat -> expr
- -> BoxyRhoType -- Expected type of whole proc expression
+ -> TcRhoType -- Expected type of whole proc expression
-> TcM (OutPat TcId, LHsCmdTop TcId, CoercionI)
tcProc pat cmd exp_ty
= newArrowScope $
- do { ((exp_ty1, res_ty), coi) <- boxySplitAppTy exp_ty
- ; ((arr_ty, arg_ty), coi1) <- boxySplitAppTy exp_ty1
+ do { (coi, (exp_ty1, res_ty)) <- matchExpectedAppTy exp_ty
+ ; (coi1, (arr_ty, arg_ty)) <- matchExpectedAppTy exp_ty1
; let cmd_env = CmdEnv { cmd_arr = arr_ty }
- ; (pat', cmd') <- tcProcPat pat arg_ty res_ty $
- tcCmdTop cmd_env cmd []
- ; let res_coi = mkTransCoI coi (mkAppTyCoI exp_ty1 coi1 res_ty IdCo)
- ; return (pat', cmd', res_coi)
- }
+ ; (pat', cmd') <- tcPat ProcExpr pat arg_ty $
+ tcCmdTop cmd_env cmd [] res_ty
+ ; let res_coi = mkTransCoI coi (mkAppTyCoI coi1 (IdCo res_ty))
+ ; return (pat', cmd', res_coi) }
\end{code}
{ expr' <- tc_cmd env expr res_ty
; return (L loc expr') }
+tc_cmd :: CmdEnv -> HsExpr Name -> (CmdStack, TcTauType) -> TcM (HsExpr TcId)
tc_cmd env (HsPar cmd) res_ty
= do { cmd' <- tcCmd env cmd res_ty
; return (HsPar cmd') }
tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
= addErrCtxt (cmdCtxt in_cmd) $ do
- (scrut', scrut_ty) <- addErrCtxt (caseScrutCtxt scrut) $
- tcInferRho scrut
+ (scrut', scrut_ty) <- tcInferRho scrut
matches' <- tcMatchesCase match_ctxt scrut_ty matches res_ty
return (HsCase scrut' matches')
where
-------------------------------------------
-- Lambda
-tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig grhss))] _))
+tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats _maybe_rhs_sig grhss))] _))
(cmd_stk, res_ty)
- = addErrCtxt (matchCtxt match_ctxt match) $
+ = addErrCtxt (pprMatchInCtxt match_ctxt match) $
do { -- Check the cmd stack is big enough
; checkTc (lengthAtLeast cmd_stk n_pats)
-- Check the patterns, and the GRHSs inside
; (pats', grhss') <- setSrcSpan mtch_loc $
- tcLamPats pats cmd_stk res_ty $
- tc_grhss grhss
+ tcPats LambdaExpr pats cmd_stk $
+ tc_grhss grhss res_ty
; let match' = L mtch_loc (Match pats' Nothing grhss')
; return (HsLam (MatchGroup [match'] res_ty))
-------------------------------------------
-- Do notation
-tc_cmd env cmd@(HsDo do_or_lc stmts body ty) (cmd_stk, res_ty)
+tc_cmd env cmd@(HsDo do_or_lc stmts body _ty) (cmd_stk, res_ty)
= do { checkTc (null cmd_stk) (nonEmptyCmdStkErr cmd)
- ; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts res_ty $
+ ; (stmts', body') <- tcStmts do_or_lc (tcMDoStmt tc_rhs) stmts res_ty $
tcGuardedCmd env body []
; return (HsDo do_or_lc stmts' body' res_ty) }
where
- tc_stmt = tcMDoStmt tc_rhs
tc_rhs rhs = do { ty <- newFlexiTyVarTy liftedTypeKind
; rhs' <- tcCmd env rhs ([], ty)
; return (rhs', ty) }
tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
= addErrCtxt (cmdCtxt cmd) $
do { cmds_w_tys <- zipWithM new_cmd_ty cmd_args [1..]
- ; span <- getSrcSpanM
; [w_tv] <- tcInstSkolTyVars ArrowSkol [alphaTyVar]
; let w_ty = mkTyVarTy w_tv -- Just a convenient starting point
e_res_ty
-- Check expr
- ; (expr', lie) <- escapeArrowScope (getLIE (tcMonoExpr expr e_ty))
- ; loc <- getInstLoc (SigOrigin ArrowSkol)
- ; inst_binds <- tcSimplifyCheck loc [w_tv] [] lie
-
- -- Check that the polymorphic variable hasn't been unified with anything
- -- and is not free in res_ty or the cmd_stk (i.e. t, t1..tn)
- ; checkSigTyVarsWrt (tyVarsOfTypes (res_ty:cmd_stk)) [w_tv]
+ ; (inst_binds, expr') <- checkConstraints ArrowSkol [w_tv] [] $
+ escapeArrowScope (tcMonoExpr expr e_ty)
-- OK, now we are in a position to unscramble
-- the s1..sm and check each cmd
; cmds' <- mapM (tc_cmd w_tv) cmds_w_tys
- ; return (HsArrForm (noLoc $ HsWrap (WpTyLam w_tv)
- (unLoc $ mkHsDictLet inst_binds expr'))
- fixity cmds')
- }
+ ; let wrap = WpTyLam w_tv <.> mkWpLet inst_binds
+ ; return (HsArrForm (mkLHsWrap wrap expr') fixity cmds') }
where
-- Make the types
-- b, ((e,s1) .. sm), s
unscramble :: TcType -> (TcType, [TcType])
-- unscramble ((w,s1) .. sn) = (w, [s1..sn])
- unscramble ty
+ unscramble ty = unscramble' ty []
+
+ unscramble' ty ss
= case tcSplitTyConApp_maybe ty of
Just (tc, [t,s]) | tc == pairTyCon
- -> let
- (w,ss) = unscramble t
- in (w, s:ss)
-
- other -> (ty, [])
+ -> unscramble' t (s:ss)
+ _ -> (ty, ss)
-----------------------------------------------------------------
-- Base case for illegal commands
-- This is where expressions that aren't commands get rejected
-tc_cmd env cmd _
- = failWithTc (vcat [ptext SLIT("The expression"), nest 2 (ppr cmd),
- ptext SLIT("was found where an arrow command was expected")])
+tc_cmd _ cmd _
+ = failWithTc (vcat [ptext (sLit "The expression"), nest 2 (ppr cmd),
+ ptext (sLit "was found where an arrow command was expected")])
\end{code}
\begin{code}
+mkPairTy :: Type -> Type -> Type
mkPairTy t1 t2 = mkTyConApp pairTyCon [t1,t2]
arrowTyConKind :: Kind -- *->*->*
%************************************************************************
\begin{code}
-cmdCtxt cmd = ptext SLIT("In the command:") <+> ppr cmd
-
-caseScrutCtxt cmd
- = hang (ptext SLIT("In the scrutinee of a case command:")) 4 (ppr cmd)
+cmdCtxt :: HsExpr Name -> SDoc
+cmdCtxt cmd = ptext (sLit "In the command:") <+> ppr cmd
+nonEmptyCmdStkErr :: HsExpr Name -> SDoc
nonEmptyCmdStkErr cmd
- = hang (ptext SLIT("Non-empty command stack at command:"))
- 4 (ppr cmd)
+ = hang (ptext (sLit "Non-empty command stack at command:"))
+ 2 (ppr cmd)
+kappaUnderflow :: HsExpr Name -> SDoc
kappaUnderflow cmd
- = hang (ptext SLIT("Command stack underflow at command:"))
- 4 (ppr cmd)
+ = hang (ptext (sLit "Command stack underflow at command:"))
+ 2 (ppr cmd)
+badFormFun :: Int -> TcType -> SDoc
badFormFun i tup_ty'
- = hang (ptext SLIT("The type of the") <+> speakNth i <+> ptext SLIT("argument of a command form has the wrong shape"))
- 4 (ptext SLIT("Argument type:") <+> ppr tup_ty')
+ = hang (ptext (sLit "The type of the") <+> speakNth i <+> ptext (sLit "argument of a command form has the wrong shape"))
+ 2 (ptext (sLit "Argument type:") <+> ppr tup_ty')
\end{code}
projects / ghc-hetmet.git / blobdiff