Could you add some more detail about why you need the net package to distinguish these? In most cases I've encountered where I want to change behavior based on whether the Context was cancelled (e.g. by suppressing log messages for things that were intentionally cancelled), it has sufficed to write something like:

	conn, err := net.DialContext(ctx, network, addr)
	if err != nil {
		if ctx.Err() != context.Canceled {
			log.Printf([…])
		}
		return […]
	}
	[…]

More generally, I've found that it's useful for functions that may involve retries and backoff to return the last real error they encountered, rather than just a Canceled or DeadlineExceeded error: that way, if the call blocks due to some other issue (e.g. a persistent DNS issue), the program can report the actual issue (e.g. the DNS error) rather than a secondary symptom of it (e.g. a dial timeout).

Could you add some more detail about why you need the net package to distinguish these? In most cases I've encountered where I want to change behavior based on whether the Context was cancelled (e.g. by suppressing log messages for things that were intentionally cancelled), it has sufficed to write something like:

I didn't think that I could have checked it in such way and I was probably looking for a way of doing so with the returned error, considering that the context cancelations errors are returned but remapped.

Such way works for what I need.

More generally, I've found that it's useful for functions that may involve retries and backoff to return the last real error they encountered, rather than just a Canceled or DeadlineExceeded error: that way, if the call blocks due to some other issue (e.g. a persistent DNS issue), the program can report the actual issue (e.g. the DNS error) rather than a secondary symptom of it (e.g. a dial timeout).

It makes sense to me.

I'm closing the issue.
Many thanks!

P.S. I've updated the links to the source of the opening comment to link to the last commit that I've just found in master for avoiding that links move around the source from time to time when master get updated and the issue can keep the context for any future reference.