It's a common operation on sets, so would make `HashSet::union` [1] and friends less obvious, for no real benefit. [1] https://doc.rust-lang.org/stable/std/col

It's a common operation on sets, so would make `HashSet::union` [1] and friends less obvious, for no real benefit. [1] https://doc.rust-lang.org/stable/std/collections/struct.HashSet.html#method.union https://doc.rust-lang.org/stable/std/collections/struct.Hash...