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 TcMType
import TcBinds
import TcSimplify
-import TcGadt
import TcPat
import TcUnify
import TcRnMonad
import SrcLoc
import Outputable
+import FastString
import Util
import Control.Monad
do { ((exp_ty1, res_ty), coi) <- boxySplitAppTy exp_ty
; ((arr_ty, arg_ty), coi1) <- boxySplitAppTy exp_ty1
; let cmd_env = CmdEnv { cmd_arr = arr_ty }
- ; (pat', cmd') <- tcProcPat pat arg_ty (emptyRefinement, res_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)
tcCmdTop :: CmdEnv
-> LHsCmdTop Name
-> CmdStack
- -> (Refinement, TcTauType) -- Expected result type; always a monotype
- -- We know exactly how many cmd args are expected,
- -- albeit perhaps not their types; so we can pass
- -- in a CmdStack
+ -> TcTauType -- Expected result type; always a monotype
+ -- We know exactly how many cmd args are expected,
+ -- albeit perhaps not their types; so we can pass
+ -- in a CmdStack
-> TcM (LHsCmdTop TcId)
-tcCmdTop env (L loc (HsCmdTop cmd _ _ names)) cmd_stk reft_res_ty@(_,res_ty)
+tcCmdTop env (L loc (HsCmdTop cmd _ _ names)) cmd_stk res_ty
= setSrcSpan loc $
- do { cmd' <- tcGuardedCmd env cmd cmd_stk reft_res_ty
+ do { cmd' <- tcGuardedCmd env cmd cmd_stk res_ty
; names' <- mapM (tcSyntaxName ProcOrigin (cmd_arr env)) names
; return (L loc $ HsCmdTop cmd' cmd_stk res_ty names') }
----------------------------------------
tcGuardedCmd :: CmdEnv -> LHsExpr Name -> CmdStack
- -> (Refinement, TcTauType) -> TcM (LHsExpr TcId)
+ -> TcTauType -> TcM (LHsExpr TcId)
-- A wrapper that deals with the refinement (if any)
-tcGuardedCmd env expr stk (reft, res_ty)
- = do { let (co, res_ty') = refineResType reft res_ty
- ; body <- tcCmd env expr (stk, res_ty')
- ; return (mkLHsWrap co body) }
+tcGuardedCmd env expr stk res_ty
+ = do { body <- tcCmd env expr (stk, res_ty)
+ ; return body
+ }
tcCmd :: CmdEnv -> LHsExpr Name -> (CmdStack, TcTauType) -> TcM (LHsExpr TcId)
-- The main recursive function
{ 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') }
-------------------------------------------
-- 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)
-------------------------------------------
-- 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 (emptyRefinement, res_ty) $
+ ; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts res_ty $
tcGuardedCmd env body []
; return (HsDo do_or_lc stmts' body' res_ty) }
where
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
not (w_tv `elemVarSet` tyVarsOfTypes arg_tys))
(badFormFun i tup_ty')
- ; tcCmdTop (env { cmd_arr = b }) cmd arg_tys (emptyRefinement, s) }
+ ; tcCmdTop (env { cmd_arr = b }) cmd arg_tys s }
unscramble :: TcType -> (TcType, [TcType])
-- unscramble ((w,s1) .. sn) = (w, [s1..sn])
(w,ss) = unscramble t
in (w, s:ss)
- other -> (ty, [])
+ _ -> (ty, [])
-----------------------------------------------------------------
-- 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
+cmdCtxt :: HsExpr Name -> SDoc
+cmdCtxt cmd = ptext (sLit "In the command:") <+> ppr cmd
+caseScrutCtxt :: LHsExpr Name -> SDoc
caseScrutCtxt cmd
- = hang (ptext SLIT("In the scrutinee of a case command:")) 4 (ppr cmd)
+ = hang (ptext (sLit "In the scrutinee of a case command:")) 4 (ppr cmd)
+nonEmptyCmdStkErr :: HsExpr Name -> SDoc
nonEmptyCmdStkErr cmd
- = hang (ptext SLIT("Non-empty command stack at command:"))
+ = hang (ptext (sLit "Non-empty command stack at command:"))
4 (ppr cmd)
+kappaUnderflow :: HsExpr Name -> SDoc
kappaUnderflow cmd
- = hang (ptext SLIT("Command stack underflow at command:"))
+ = hang (ptext (sLit "Command stack underflow at command:"))
4 (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"))
+ 4 (ptext (sLit "Argument type:") <+> ppr tup_ty')
\end{code}
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