DMD supports ranges, but druntime can't see them?

[jmh530]

On Thursday, 23 May 2019 at 11:00:13 UTC, Mike Franklin wrote:
> [snip]
>
> This is where I disagree because I'm trying to make the 
> language opt-in and pay-as-you-go.  What I'm envisioning is a 
> "Language as a Library".  If one wants classes they `import 
> classes;`.  If one wants exceptions, they `import exceptions;` 
> etc.  The modules one imports contain the compiler lowerings 
> and other constructs to support the feature.  The compiler will 
> emit an error if it can't find something that's not imported, 
> including the compiler hooks, (just like it does today if one 
> tries to use a symbol that isn't imported)  Users opt-in to a 
> feature by importing the feature.  Note that this behavior is 
> predicated on work being done to move all runtime lowerings 
> into the semantic phase of the compiler instead of the IR stage 
> like it is today.  That work is currently underway.
>

I like the sound of this, though I think it would be helpful to 
have some sense of the size of the impact (on compile-times, 
run-times, and memory, at least) when those features are used 
(and not just when they are not used).