Dlist and dip1000 challenge

[Walter Bright]

On 10/25/2018 6:50 AM, Steven Schveighoffer wrote:
> I know this debate is continuing. But that PR has nothing to do with the problem 
> I'm having (what this post is really about). I'm not returning anything via the 
> first parameter. Just for kicks, I downloaded your PR branch, and it still has 
> the same problem with somehow assuming something is scope. So can you address 
> this problem at all?

The problems people have with DIP1000 nearly always stem from the code being 
complicated. The code example you posted is quite complicated with a lot of 
moving parts. The only way to get a handle on what is happening is to break it 
down into small, and I mean small, chunks.

The trick to finding out why a chunk of code is being inferred as not @safe is 
to mark it @safe and thereby see where the error is.

Some designs are unworkable with scope without some unsafe casting. A linked 
list may be one of them (I believe the same holds for linked lists in Rust, but 
I'm not sure if I remember that correctly).

And lastly, I've done this with Phobos. Phobos is absurdly and ridiculously 
tangled code with layers and layers and layers of templates that all just 
forward to yet another template. It makes it pretty hard to track down DIP1000 
errors. DIP1000 is not terribly usable when Phobos can't be built with DIP1000, 
and that requires the PR to make progress on that.

Therefore DIP1000 is pretty dead in the water without the PR.