Main.is_top_let is not correct
Some tokens in is_top_let do not imply that the following LET is toplevel. In particular, AMPERAMPER leads to incorrect indentation in typing/btype.ml of the ocaml compiler (there is a " ... && let x = "). I think some other tokens should also be removed, but I did not find code showing the issue for them yet.
Fabrice Le Fessant