symfony/symfony — comment on commit 789d5ad20f5d3e63265b361c8c16230c2c070a96
File: src/Symfony/Bundle/FrameworkBundle/HttpKernel.php line 112
By stof:

@stloyd the request can still be passed as an argument to the controller. But it makes no sense to pass a Request instance to the subrequest as the instance passed to the controller will be the Request object created for the HTTP request (be it a subrequest or a master request for ESI).