You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stub_specification.rb
    path of file: ./repos/ruby/lib/rubygems
    
    the code of the file until where you have to start completion: # frozen_string_literal: t
    
  def missing_extensions?
    return false if default_gem?
    return false if extensions.empty?
    return false if File.exist? gem_build_complete_path

    to_spec.missing_extensions?
  end