\begin{code}
module TcArrows ( tcProc ) where
-import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho )
+import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho, tcSyntaxOp )
import HsSyn
-import TcHsSyn
-
import TcMatches
-
import TcType
import TcMType
import TcBinds
-import TcSimplify
import TcPat
import TcUnify
import TcRnMonad
\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') <- tcPat ProcExpr 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}
mc_body = mc_body }
mc_body body res_ty' = tcGuardedCmd env body stk res_ty'
-tc_cmd env (HsIf pred b1 b2) res_ty
- = do { pred' <- tcMonoExpr pred boolTy
- ; b1' <- tcCmd env b1 res_ty
- ; b2' <- tcCmd env b2 res_ty
- ; return (HsIf pred' b1' b2')
+tc_cmd env (HsIf mb_fun pred b1 b2) (stack_ty,res_ty)
+ = do { pred_ty <- newFlexiTyVarTy openTypeKind
+ ; b_ty <- newFlexiTyVarTy openTypeKind
+ ; let if_ty = mkFunTys [pred_ty, b_ty, b_ty] res_ty
+ ; mb_fun' <- case mb_fun of
+ Nothing -> return Nothing
+ Just fun -> liftM Just (tcSyntaxOp IfOrigin fun if_ty)
+ ; pred' <- tcMonoExpr pred pred_ty
+ ; b1' <- tcCmd env b1 (stack_ty,b_ty)
+ ; b2' <- tcCmd env b2 (stack_ty,b_ty)
+ ; return (HsIf mb_fun' pred' b1' b2')
}
-------------------------------------------
(kappaUnderflow cmd)
-- Check the patterns, and the GRHSs inside
- ; (pats', grhss') <- setSrcSpan mtch_loc $
- tcPats LambdaExpr pats cmd_stk res_ty $
- tc_grhss grhss
+ ; (pats', grhss') <- setSrcSpan mtch_loc $
+ 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))
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
nonEmptyCmdStkErr :: HsExpr Name -> SDoc
nonEmptyCmdStkErr cmd
= hang (ptext (sLit "Non-empty command stack at command:"))
- 4 (ppr cmd)
+ 2 (ppr cmd)
kappaUnderflow :: HsExpr Name -> SDoc
kappaUnderflow cmd
= hang (ptext (sLit "Command stack underflow at command:"))
- 4 (ppr cmd)
+ 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')
+ 2 (ptext (sLit "Argument type:") <+> ppr tup_ty')
\end{code}