(* L.warn "entering R.are_convertible"; *)
let rec aux m1 r1 m2 r2 =
(* L.warn "entering R.are_convertible_aux"; *)
let u, t = term_of_whdr r1, term_of_whdr r2 in
(* L.warn "entering R.are_convertible"; *)
let rec aux m1 r1 m2 r2 =
(* L.warn "entering R.are_convertible_aux"; *)
let u, t = term_of_whdr r1, term_of_whdr r2 in