X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcArrows.lhs;h=5d9273880ff07f125851f70472aad17564190c11;hp=14e561b3e08fc0121cff913343da58a2db9c8ede;hb=d76d9636aeebe933d160157331b8c8c0087e73ac;hpb=d2ce0f52d42edf32bb9f13796e6ba6edba8bd516

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index 14e561b..5d92738 100644
--- a/compiler/typecheck/TcArrows.lhs
+++ b/compiler/typecheck/TcArrows.lhs
@@ -7,7 +7,7 @@ Typecheck arrow notation
 \begin{code}
 module TcArrows ( tcProc ) where
 
-import {-# SOURCE #-}	TcExpr( tcMonoExpr, tcInferRho )
+import {-# SOURCE #-}	TcExpr( tcMonoExpr, tcInferRho, tcSyntaxOp )
 
 import HsSyn
 import TcMatches
@@ -48,7 +48,7 @@ tcProc pat cmd exp_ty
     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) }
@@ -125,11 +125,17 @@ tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
                       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')
     }
 
 -------------------------------------------
@@ -180,8 +186,8 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats _maybe_rhs_sig
 		  (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')
@@ -200,18 +206,17 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats _maybe_rhs_sig
 	     ; return (GRHSs grhss' binds') }
 
     tc_grhs res_ty (GRHS guards body)
-	= do { (guards', rhs') <- tcStmts pg_ctxt tcGuardStmt guards res_ty $
+	= do { (guards', rhs') <- tcStmtsAndThen pg_ctxt tcGuardStmt guards res_ty $
 				  tcGuardedCmd env body stk'
 	     ; return (GRHS guards' rhs') }
 
 -------------------------------------------
 -- 		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 _) (cmd_stk, res_ty)
   = do 	{ checkTc (null cmd_stk) (nonEmptyCmdStkErr cmd)
-	; (stmts', body') <- tcStmts do_or_lc (tcMDoStmt tc_rhs) stmts res_ty $
-			     tcGuardedCmd env body []
-	; return (HsDo do_or_lc stmts' body' res_ty) }
+	; stmts' <- tcStmts do_or_lc (tcMDoStmt tc_rhs) stmts res_ty 
+	; return (HsDo do_or_lc stmts' res_ty) }
   where
     tc_rhs rhs = do { ty <- newFlexiTyVarTy liftedTypeKind
 		    ; rhs' <- tcCmd env rhs ([], ty)
@@ -231,7 +236,7 @@ tc_cmd env cmd@(HsDo do_or_lc stmts body _ty) (cmd_stk, res_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..]
-	; [w_tv]     <- tcInstSkolTyVars ArrowSkol [alphaTyVar]
+        ; [w_tv]     <- tcInstSkolTyVars [alphaTyVar]
 	; let w_ty = mkTyVarTy w_tv 	-- Just a convenient starting point
 
 		--  a ((w,t1) .. tn) t
@@ -241,10 +246,9 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 		--   -> 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