Is there any good reason why C++ namespaces are "closed" in D?

[Walter Bright]

On 8/5/2018 9:53 PM, Manu wrote:
> If we produce a DIP to fix this, will you reject it in principle?

Producing a DIP is a good idea, it provides an anchor point for any future 
discussion of the topic, rather than the tangle and noise that is this thread. 
It is an ample opportunity to put the best foot forward on your ideas.

I'm not going to categorically say we'll reject it, but will say that you'll 
need to make a more compelling case, and a DIP is the right method for that. 
Please keep in mind that a good DIP will address the counterarguments and other 
methods of solving the issue.

As this thread affirms, trying to design things in the forums doesn't work very 
well, and I should have asked for a DIP in the first place.