Annoyance with new integer promotion deprecations

[Stefan Koch]

On Tuesday, 6 February 2018 at 20:23:02 UTC, Walter Bright wrote:
> [...] DFA is a complex thing. This is why DFA is done on the 
> vastly simplified and canonicalized intermediate code, not the 
> ASTs.
>
> Doing DFA for VRP means doing it on the ASTs.
>
> I know what you're asking for sounds simple enough. But it 
> ain't.

What you're saying is true.
There is a way though to have the cake and eat it.
If IR keeps a backwards-transform to the AST, (whereby I mean the 
semantically-augmented tree closest to the actual AST).

It is possible to transfer insight gained further in the 
processing to earlier constructs.
Making it possible to extend VRP.

This might negativity impact compile-times, and it (maybe) won't 
be simple to implement.