Possible bugs involving CCBV.{set, diff, union}

[favonia]

The program

let () =
  let v1 = CCBV.empty () in
  let () = CCBV.set v1 64 in
  let v2 = CCBV.diff (CCBV.empty ()) (CCBV.empty ()) in
  let v3 = CCBV.union v1 v2 in
  Format.printf "union (%a, %a)@.==>@.%a@." CCBV.pp v1 CCBV.pp v2 CCBV.pp v3

on at least one computer would output

union (bv {00000000000000000000000000000000000000000000000000000000000000001}, bv {})
==>
bv {00000000000000000000000000000000000000000000000000000000000000011}

Notice the two 1s at the end of the result of the union. There should only be one 1.

The bug was discovered in a relatively complicated program, and in the original context 64 can be replaced by a much smaller number (e.g., 5). However, 64 is the smallest number for the above standalone program to demonstrate the bug on my machine. By the way, I was using v3.4 but none of the later commits seemed to touch the CCBV module, and thus I believe the bug is still in the master branch.

[c-cube]

Thank you for the report, that was tricky indeed. It should be fixed now.