application.rb

Rails.application.eager_load!  #ensure all controllers are loaded

ApplicationController.descendants.each do |controller|
  puts "#{controller.name}"
end

output

RAILS_ENV=development bundle exec rake assets:precompile
rake aborted!
LoadError: No such file to load -- application_controller
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:424:in `load'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:424:in `block in load_file'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:616:in `new_constants_in'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:423:in `load_file'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:324:in `require_or_load'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:289:in `depend_on'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:207:in `require_dependency'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:465:in `block (2 levels) in eager_load!'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:464:in `each'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:464:in `block in eager_load!'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:462:in `each'
/Users/dstarh/.rvm/gems/ruby-2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:462:in `eager_load!'
/Users/dstarh/interfaze/config/application.rb:51:in `<class:Application>'
/Users/dstarh/interfaze/config/application.rb:20:in `<module:Interface>'
/Users/dstarh/interfaze/config/application.rb:19:in `<top (required)>'
/Users/dstarh/interfaze/Rakefile:4:in `require'
/Users/dstarh/interfaze/Rakefile:4:in `<top (required)>'
/Users/dstarh/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `eval'
/Users/dstarh/.rvm/gems/ruby-2.1.1/bin/ruby_executable_hooks:15:in `<main>'