我正在使用Rails 4.2。
在我的rails项目目录中，我有一个前端目录：
/railsproject/frontend
/railsproject/frontend/styles
/railsproject/frontend/styles/main.scss
我已将config.assets.paths << Rails.root.join("frontend","styles")添加到application.rb。
在/railsproject/app/assets/stylesheets/application.css.scss：
@import "main.scss";
在开发模式下一切正常。
但是当我尝试预编译生产时，它失败了：
$ RAILS_ENV=production bundle exec rake assets:precompile --trace
** Invoke assets:precompile (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
** Invoke environment (first_time)
** Execute environment
** Execute assets:precompile
rake aborted!
Sass::SyntaxError: File to import not found or unreadable: main.scss.
(sass):17
/Users/max/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/sass-3.4.15/lib/sass/tree/import_node.rb:67:in `rescue in import'
/Users/max/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/sass-3.4.15/lib/sass/tree/import_node.rb:45:in `import'
/Users/max/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/sass-3.4.15/lib/sass/tree/import_node.rb:28:in `imported_file'
/Users/max/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/sass-3.4.15/lib/sass/tree/import_node.rb:37:in `css_import?'
etc...