Nested scopes bug report

test.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # gem "rails", "~> 5.1.0" # works
  gem "rails", "~> 5.2.0" # does not work
end

require "active_support"
require "active_support/core_ext/object/blank"
require "minitest/autorun"

require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger

  routes.draw do
    scope "(:locale)" do
      scope "(:platform)" do
        root to: "projects#index"
      end
    end
  end
end

class BugTest < Minitest::Test
  include Rails.application.routes.url_helpers

  def test_root_path_with_provided_optional_scope
    assert_equal root_path(locale: 'locale'), '/locale'
    assert_equal root_path(locale: 'locale', platform: 'platform'), '/locale/platform'
  end
end