What is visual studio complaining about here? 
Code
PoolsGrid = Ext.extend(SearchableGrid, {
initComponent: function() {
var me = this;
var config = {
url: @(Url.ParameterlessRelativeTemplate<PoolsController>(x => x.List(null)))
}
}
});
More code:
public static IHtmlString ParameterlessRelativeTemplate<TController>(this UrlHelper url,
Expression<Action<TController>> action)
where TController : Controller
{
return RelativeTemplate(url, action, true);
}
The code looks fine. Ignore the error and run your application (Ctrl+F5). It should work fine. Visual Studio Intellisense in Razor views is far from perfect. Hopefully they will improve it in future versions.