Official compiler

[David Nadlinger via Digitalmars-d]

On Friday, 26 February 2016 at 18:19:57 UTC, Steven Schveighoffer 
wrote:
> The idea is that ldc and gdc will get plenty of warning if 
> something breaks.

As stated, this in itself would be utterly useless. Right now, 
you can be absolutely certain that the AST semantics will change 
in between each DMD release. Sometimes in obvious ways because 
fields are removed and so on, but much more often silently and in 
a hard-to-track-down fashion because the structure of the AST or 
the interpretation of certain node properties changes.

In other words, we don't need any warning that something breaks, 
because we already know it will. The people that need the warning 
are the authors of the breaking front-end commits, so that they 
can properly document the changes and make sure they are 
acceptable for the other backends (right now, you typically have 
to reverse-engineer that from the DMD glue layer changes). 
Ideally, of course, no such changes would be merged without 
making sure that all the backends have already been adapted for 
them first.

  — David