[r2005-07-08 13:21:03 by afrisch] Accept nested record merges in types

Original author: afrisch
Date: 2005-07-08 13:21:03+00:00

typing/typepat.ml

@@ -600,7 +600,7 @@ open Ident
 	  n.desc <- ILink (elim_conc a b)
       | IMerge (a,b) ->
 	  if (n.sid > 0) 
-	  then 	raise (Patterns.Error "Ill-formed concatenation loop");
+	  then 	raise (Patterns.Error "Ill-formed merge loop");
 	  n.sid <- 1;
 	  n.desc <- ILink (elim_merge a b)
       | _ -> ()
@@ -619,7 +619,11 @@ open Ident
       mk_record  (o1||o2) (LabelMap.merge (fun _ x -> x) l1 l2) in
     (* Problem: repr can loop with ill-formed recursion.
        type t = s + t where s = s | s;; *)
-    match (repr a).desc, (repr b).desc with
+
+    let a = repr a  and b = repr b in
+    elim_concat a; elim_concat b;
+    let a = repr a  and b = repr b in
+    match a.desc, b.desc with
       | IType (t1,_), IType (t2,_) -> 
 	  if not (Types.subtype t1 Types.Record.any) then
 	    raise