\begin{code}
module TcArrows ( tcProc ) where
-import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho )
+import {-# SOURCE #-} TcExpr( tcMonoExpr, tcInferRho, tcSyntaxOp )
import HsSyn
import TcMatches
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 $
+ ; (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) }
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 $
+ ; (pats', grhss') <- setSrcSpan mtch_loc $
+ tcPats LambdaExpr pats cmd_stk $
tc_grhss grhss res_ty
; let match' = L mtch_loc (Match pats' Nothing grhss')
-- -> a ((w,t1) .. tn) t
; let e_ty = mkFunTys [mkAppTys b [tup,s] | (_,_,b,tup,s) <- cmds_w_tys]
e_res_ty
- free_tvs = tyVarsOfTypes (res_ty:cmd_stk)
-- Check expr
- ; (inst_binds, expr') <- checkConstraints ArrowSkol free_tvs [w_tv] [] $
+ ; (inst_binds, expr') <- checkConstraints ArrowSkol [w_tv] [] $
escapeArrowScope (tcMonoExpr expr e_ty)
-- OK, now we are in a position to unscramble