当地一切正常，但是当推到Heroku时：
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_carousel.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_hero-unit.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/bc1b787c8640c68bf42fc69efbef227d36428060/_utilities.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/exams.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/home.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/lessons.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/questions.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/scaffolds.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
Warning. Error encountered while saving cache /tmp/build_1b5c442a-d24e-4f80-9755-a0bd15d7f029/tmp/cache/sass/5b1569a9810eac207f22942f2921f0820863a2d6/sections.css.scssc: can't dump anonymous class #<Class:0x007f2583f02288>
最终我得到：
Warning. Error encountered while saving cache /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/tmp/cache/sass/6b13061e65d1f1cd905accb7f7211a333a70c956/sections.css.scssc: can't dump anonymous class #<Class:0x007f02dbceaa88>
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/Rakefile:7)
DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released. (called from <top (required)> at /tmp/build_ccaceaf0-2d8f-4d84-8284-9f5fcb7ced3f/Rakefile:7)
! Timed out compiling Ruby app (15 minutes)
! See https://devcenter.heroku.com/articles/slug-compiler#time-limit
我只粘贴了出现的次数的一小部分。
我的gemfile：
ruby '2.0.0'
gem 'rails', '3.2.11'
group :assets do
gem 'sass-rails' #, '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
gem 'bootstrap-sass'#, '2.3.2.0'
gem 'cancan'
gem 'devise'
gem 'figaro'
gem 'haml-rails'
gem 'mongoid'
gem 'rolify'
gem 'simple_form'
gem 'thin'
gem 'country_select'
group :development do
gem 'better_errors'
gem 'binding_of_caller', :platforms=>[:mri_19, :rbx]
gem 'guard-bundler'
gem 'guard-rails'
gem 'guard-rspec'
gem 'html2haml'
gem 'quiet_assets'
gem 'rb-fchange', :require=>false
gem 'rb-fsevent', :require=>false
gem 'rb-inotify', :require=>false
gem "switch_user"
end
group :development, :test do
gem 'factory_girl_rails'
gem 'rspec-rails'
end
group :test do
gem 'database_cleaner'
gem 'email_spec'
gem 'mongoid-rspec'
end
gem "ckeditor"
#gem "binding_of_caller"
gem "mongoid-paperclip", :require => "mongoid_paperclip", :git=>'https://github.com/meskyanichi/mongoid-paperclip'
gem 'aws-sdk', '~> 1.3.4'
gem "flat-ui-rails"
gem 'stripe', :git => 'https://github.com/stripe/stripe-ruby'
gem "mongoid_slug", "~> 2.0.1"
我的production.rb文件具有以下属性启用
config.cache_classes = true
config.consider_all_requests_local = false
config.action_controller.perform_caching = true
config.serve_static_assets = true
config.assets.compress = true
config.assets.compile = false
config.assets.digest = true
config.assets.initialize_on_precompile = false
我的铁轨版本是轨道3.2.11
这与Sass Gem最近升级到3.3.0有关。Sass Gem是其他几个Sass Gem的依赖性，因此，即使您在Gemfile中没有它，也可能正在加载它。在本地和Heroku上进行"捆绑表演"，我很确定您会看到它们是不同的版本（Sass在几天前升级到3.3.0）。
add：
gem 'sass', '3.2.13'
到您的Gemfile，这应该为您解决问题。然后去Github上的该宝石提交问题。
希望这对我有帮助！
这是SASS 3.3.0中的一个已知错误，链轮进口商是无关紧要的，因此不可移动导致此错误。对于错误报告，请参阅此信息。如果没有缓存，Sass会汇编的速度非常缓慢，从而导致Heroku服务器上的超时。
首先，您可能需要更新
bundle update sass-rails
bundle update sass
则更关键的部分（请确保您卸载了gemfile.lock中的SASS版本）
gem uninstall sass
bundle install