Transitions to new language semantics

[Ola Fosheim Grøstad]

On Friday, 11 June 2021 at 13:10:23 UTC, zjh wrote:
> In my opinion, the `Big change` is to divide large files into 
> small files, so that the granularity of source files is smaller 
> and the dependency relationship is clearer.

There is really no need to start with a big change. The best 
approach is to:

1. First insulate independent parts. So, insulate the backend 
from the front end, by putting a layer between (most likely a 
high level IR).

2. Then move independent things like inlining out of the frontend 
and onto the middle layer.

3. Modularize.

4. Iterate between redesigning interfaces / refactoring frontend 
internals.

The frontend really only need to deal with type unification, 
templates and CRFE. Maybe I missed something, but roughly.

When you have reduced the complexity of the front end then you 
can start to modularize it. Otherwise you end up doing the job 
twice.