+ List.iter
+ (function
+ | `Obj (uri,_) -> NUri.UriHash.remove cache uri
+ | `Constr (strict,[_,u1],[_,u2]) as c ->
+ let w = strict,u1,u2 in
+ if not(List.mem c !history) then
+ le_constraints := List.filter ((<>) w) !le_constraints;
+ | `Constr _ -> assert false
+ ) to_be_deleted