class Byebug::LocalInterface

def without_readline_completion


making use of Readline.
dependent on them being loaded. Disable those while byebug is the REPL
Other gems, for example, IRB could've installed completion procs that are

Disable any Readline completion procs.
def without_readline_completion
  orig_completion = Readline.completion_proc
  return yield unless orig_completion
  begin
    Readline.completion_proc = ->(_) { nil }
    yield
  ensure
    Readline.completion_proc = orig_completion
  end
end