Remove remaining warnings on _trace by adding parenthesis to gsub arguments.

actionpack/lib/action_dispatch/middleware/templates/rescues/_trace.erb

@@ -12,14 +12,14 @@
 <div id="traces">
   <% names.each do |name| %>
     <%
-      show = "document.getElementById('#{name.gsub /\s/, '-'}').style.display='block';"
-      hide = (names - [name]).collect {|hide_name| "document.getElementById('#{hide_name.gsub /\s/, '-'}').style.display='none';"}
+      show = "document.getElementById('#{name.gsub(/\s/, '-')}').style.display='block';"
+      hide = (names - [name]).collect {|hide_name| "document.getElementById('#{hide_name.gsub(/\s/, '-')}').style.display='none';"}
     %>
     <a href="#" onclick="<%= hide.join %><%= show %>; return false;"><%= name %></a> <%= '|' unless names.last == name %>
   <% end %>
 
   <% traces.each do |name, trace| %>
-    <div id="<%= name.gsub /\s/, '-' %>" style="display: <%= (name == "Application Trace") ? 'block' : 'none' %>;">
+    <div id="<%= name.gsub(/\s/, '-') %>" style="display: <%= (name == "Application Trace") ? 'block' : 'none' %>;">
       <pre><code><%=h trace.join "\n" %></code></pre>
     </div>
   <% end %>