title: TypeError (no _dump_data is defined for class Proc):
body: <p>I am trying to store a value in the session using the below code in my rails application </p>
  
  <pre><code>session[:key] = value 
  </code></pre>
  
  <p>And i get the below error </p>
  
  <pre><code>TypeError (no _dump_data is defined for class Proc):
  activesupport (3.2.9) lib/active_support/message_verifier.rb:53:in `dump'
   activesupport (3.2.9) lib/active_support/message_verifier.rb:53:in `generate'
   actionpack (3.2.9) lib/action_dispatch/middleware/cookies.rb:300:in `[]='
  actionpack (3.2.9) lib/action_dispatch/middleware/session/cookie_store.rb:67:in    `set_cookie'
  rack (1.4.1) lib/rack/session/abstract/id.rb:330:in `commit_session'
  rack (1.4.1) lib/rack/session/abstract/id.rb:206:in `context'
  rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/cookies.rb:341:in `call'
  activerecord (3.2.9) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.9)    lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
  actionpack (3.2.9) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.9) lib/active_support/callbacks.rb:405:in `
  </code></pre>
  
  <p>Any help is highly appreciated.</p>