I am trying to write a queue and I'd need to "grow" my buffered chans, is there a way to do that without having to create a new one and moving the elements to the new one?
It is not possible with standard channels. However by using an intermediate goroutine with a few tricks you can make something that's effectively equivalent. It will, however, be somewhat slower than a native channel. This is implemented as the ResizableChannel in the channels package (disclaimer: I wrote it).
Why would you want to grow the chan size? Are you looking to have a chan where you can keep writing regardless whether there are readers or not?
If so, you should use a goroutine which will own the queue and two chans (read chan and a write chan). The goroutine will keep a slice of items internaly with all the written items (received via write chan) and it will keep attempting to write to the read chan which will block till there are readers reading from it.
hope this helps