diff --git a/lib/sprockets/rails/helper.rb b/lib/sprockets/rails/helper.rb
index 62491dfc..01f9f7e9 100644
--- a/lib/sprockets/rails/helper.rb
+++ b/lib/sprockets/rails/helper.rb
@@ -7,15 +7,16 @@ module Sprockets
   module Rails
     module Helper
       class AssetNotFound < StandardError; end
+      class AssetNotPrecompiled < StandardError; end
 
-      class AssetNotPrecompiled < StandardError
+      class AssetNotPrecompiledError < AssetNotPrecompiled
         include Sprockets::Rails::Utils
         def initialize(source)
           msg =
           if using_sprockets4?
             "Asset `#{ source }` was not declared to be precompiled in production.\n" +
             "Declare links to your assets in `app/assets/config/manifest.js`.\n\n" +
-            "  //= link #{ source }\n" +
+            "  //= link #{ source }\n\n" +
             "and restart your server"
           else
             "Asset was not declared to be precompiled in production.\n" +