:private param for const_set
Defining a private constant should not require two method calls.
You want to encourage private declarations because they communicate intent better and are easier to refactor, two statements discourage it.
Ideally there should be compact syntax for direct private declarations, but that's probably a difficult change.
const_set :FOO, 1, private: true or
const_set :FOO, 1, :private should be trivial