Breaking D2 language/spec changes with D1 being discontinued in a month

[Walter Bright]

On 11/29/2012 12:15 AM, Jacob Carlborg wrote:
> Many people has also talked about something in between D1 and D2, D1.5
> or similar. Which would contain bug fixes and new backwards compilable
> changes.


The trouble with that is now I'd be maintaining 3 versions of the 
compiler rather than two.

Here's what happens nearly all the time. People create a pull request 
for a fix to D2. I don't just pull it, I review it and see if it is a 
fix that should be propagated to D1. If it is, I have to manually merge 
it into D1 (as the sources have substantially diverged by now). This 
gets fairly time consuming. Check the D1 commits labeled along the lines 
of "merge D2 pull #nnnn".

Only a relatively small handful of times has anyone submitted a 
corresponding pull request for D1.

Adding a 3rd compiler to do this to is a large time sink.

I can see creating a stable D2 and a forward D2 for 6 months at a time 
or so, as has been proposed here. I think that's a good idea. But only 
after D1 is no longer supported.