File "w33.ml", line 19, characters 6-11:
19 | let f M.(x) = x (* useless open *)
           ^^^^^
Warning 33 [unused-open]: unused open M.

File "w33.ml", line 26, characters 0-7:
26 | open! M (* useless open! *)
     ^^^^^^^
Warning 66 [unused-open-bang]: unused open! M.

File "w33.ml", line 27, characters 0-6:
27 | open M (* useless open *)
     ^^^^^^
Warning 33 [unused-open]: unused open M.