Warn on unused imports?

[FeepingCreature]

On Tuesday, 25 September 2018 at 13:14:36 UTC, Jonathan M Davis 
wrote:
> If something is definitively wrong, then it should be an error. 
> If it's not definitively wrong, then the compiler shouldn't say 
> anything about it, and it should be left up to a linter tool of 
> some kind like dcd.
>
> - Jonathan M Davis

If that's the way D wanted to go, it shouldn't have turned itself 
into a metaprogramming monster that's completely unevaluable by 
Linter tools, *or* it should offer some way to dump a 
fixed-format lowered representation with line number information 
that tools can analyze. As it stands, it is literally impossible 
to evaluate whether an import is unused without evaluating the 
entire compile-time subset of D.