diff options
| -rw-r--r-- | plugins/extraction/mlutil.ml | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/plugins/extraction/mlutil.ml b/plugins/extraction/mlutil.ml index 4ab7b6f75..03b62f836 100644 --- a/plugins/extraction/mlutil.ml +++ b/plugins/extraction/mlutil.ml @@ -96,22 +96,17 @@ let rec type_occurs alpha t = let rec mgu = function | Tmeta m, Tmeta m' when m.id = m'.id -> () - | Tmeta m, t when m.contents=None -> - if type_occurs m.id t then raise Impossible - else m.contents <- Some t - | t, Tmeta m when m.contents=None -> - if type_occurs m.id t then raise Impossible - else m.contents <- Some t - | Tmeta {contents=Some u}, t -> mgu (u, t) - | t, Tmeta {contents=Some u} -> mgu (t, u) + | Tmeta m, t | t, Tmeta m -> + (match m.contents with + | Some u -> mgu (u, t) + | None when type_occurs m.id t -> raise Impossible + | None -> m.contents <- Some t) | Tarr(a, b), Tarr(a', b') -> mgu (a, a'); mgu (b, b') | Tglob (r,l), Tglob (r',l') when r = r' -> List.iter mgu (List.combine l l') - | Tvar i, Tvar j when i = j -> () - | Tvar' i, Tvar' j when i = j -> () | Tdummy _, Tdummy _ -> () - | Tunknown, Tunknown -> () + | t, u when t = u -> () (* for Tvar, Tvar', Tunknown, Taxiom *) | _ -> raise Impossible let needs_magic p = try mgu p; false with Impossible -> true |