Warning 44 on overriding a pervasive operator


A Cmdliner.Arg module defines an (&) operator that, AFAIU, does exactly the same as (@@) (even though & has lower precedence).

Now, when you try to actually use it, it results in a warning:

  Warning number 44
  /home/hoichi/dev/bsdoc/src/Cli.re 107:7-111:8
  105 ┆ let out_dir = {
  106 ┆   let doc = "Output directory of the generated documentation";
  107 ┆   Arg.(
  108 ┆     value
  109 ┆     & opt(file, "./docs")
  110 ┆     & info(["o", "output-dir"], ~docv="DIR", ~doc)
  111 ┆   );
  112 ┆ };
  113 ┆ 
  this open statement shadows the value identifier & (which is later used)

Question 1 (a practical one): What’s the best way to fix it? Simply replacing &s with @@s seem to work: simply opening the module doesn’t trigger the warning, using the operator does. But there should be a reason why the cmdliner author(s) defined & (it sure does look better).
Questions 2 and 3 (just wondering). Is the warning happening on every ambiguous shadowing? “later used” sounds a bit misleading for the Foo.() usage, when the shadowing is very local. And: how come nobody complained about this to cmdliner before? Maybe bsdoc does something wrong?