why to (not) support "older" compiler versions

[drug via Digitalmars-d]

On 03.11.2015 15:50, Iain Buclaw via Digitalmars-d wrote:
>
> Well, how would that work?  :-)
>
> What you've probably misheard is half of a phrase.  Moving to towards
> ddmd is not to be confused with moving towards a shared 'frontend'
> codebase, and is the first half of the correct sentence.  The second
> half is that even then, that has no guarantee of keeping things in sync
> without also integrating other 'ends' into the CI process.
>
> This requires that we set-up an infrastructure where:
>
> - New PRs are tested against all compilers before merging.  This not to
> be confused with our current set-up where all compilers build DMD.
> Specifically new changes upstream must:
>    1. Be able to apply the change cleanly in their local repositories
>    2. Build themselves without error.
> - We then need another process in place to keep each end in sync after
> changes upstream are applied.
>
> It was hoped that moving towards ddmd would force a lot of the
> ABI-specific code to be moved into Target or Port (host) interfaces that
> are agnostic to the backend.  There are still many target-specific areas
> where this is not the case, and on top of that there are regressions in
> the host-specific interfaces.
>
> In short, there will always be a heavy maintenance burden regardless of
> what language we're written in. :-)
>
> Iain
I see. Thank you for your answer!