Prism::WhenNode#then_keyword_loc

# File tmp/rubies/ruby-3.4.1/lib/prism/node.rb, line 17915
def then_keyword_loc
  location = @then_keyword_loc
  case location
  when nil
    nil
  when Location
    location
  else
    @then_keyword_loc = Location.new(source, location >> 32, location & 0xFFFFFFFF)
  end
end