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symmetry of unify_univar 

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@6376 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
master
Jacques Garrigue 2004-06-08 06:34:56 +00:00
parent 6ca9627bfa
commit 4f0631da37
1 changed files with 15 additions and 15 deletions
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30
typing/ctype.ml
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@ -1225,21 +1225,21 @@ let occur env ty0 ty =
be done at meta-level, using bindings in univar_pairs *)
let rec unify_univar t1 t2 = function
(cl1, cl2) :: rem ->
let repr_univ = List.map (fun (t,o) -> repr t, o) in
let cl1 = repr_univ cl1 and cl2 = repr_univ cl2 in
begin try
let r1 = List.assq t1 cl1 in
match !r1 with
Some t -> if t2 != repr t then raise (Unify [])
| None ->
try
let r2 = List.assq t2 cl2 in
if !r2 <> None then raise (Unify []);
set_univar r1 t2; set_univar r2 t1
with Not_found ->
raise (Unify [])
with Not_found ->
unify_univar t1 t2 rem
let find_univ t cl =
try
let (_, r) = List.find (fun (t',_) -> t == repr t') cl in
Some r
with Not_found -> None
in
begin match find_univ t1 cl1, find_univ t2 cl2 with
Some {contents=Some t'2}, Some _ when t2 == repr t'2 ->
()
| Some({contents=None} as r1), Some({contents=None} as r2) ->
set_univar r1 t2; set_univar r2 t1
| None, None ->
unify_univar t1 t2 rem
| _ ->
raise (Unify [])
end
| [] -> raise (Unify [])