You know how I was saying in my DConf talk...

[Timon Gehr]

On 24.07.19 04:12, Ethan wrote:
> On Wednesday, 24 July 2019 at 01:10:34 UTC, Ethan wrote:
>> On Wednesday, 24 July 2019 at 01:06:18 UTC, Ethan wrote:
>>>
>>
>> It's 4am and I was planning on having a major feature finished 8 hours 
>> ago, but I've been running in to static foreach and mixin bugs all day.
> 
> https://issues.dlang.org/show_bug.cgi?id=20079
> https://issues.dlang.org/show_bug.cgi?id=20080
> ...

This behavior is by design (for the better or worse, but those are not 
compiler bugs). You'd need to alias the mixin-template-local symbols 
into the current scope, or use string mixins instead of template mixins.

> ........and when trying to get to sleep, I decided to try forward 
> declarations for the functions I was having issues with in mixins. And 
> finally hit upon what I think are the root problems I've been having.
> 
> Mixin templates have been broken in one way or another since I started 
> using D in 2012. This static foreach bug I've found just seems to 
> highlight to me that the method of defining a separate scope and 
> importing in to the parent after the fact just plain doesn't work.

mixin templates are _designed_ that way, but `static foreach` doesn't 
work like this. The additional scopes are introduced for the purpose of 
containing the `static foreach` loop variable symbols, the symbols 
generated by `static foreach` themselves are _not_ treated like template 
mixins, they are inserted into the symbol table of the enclosing scope, 
but they need to be analyzed in the inner scope so the `static foreach` 
loop variable is visible.

The `static foreach` implementation explicitly skips scopes containing 
`static foreach` loop variables (the __anonymous in the error messages) 
when determining parent symbols, so there is something weird going on. 
I'm trying to look into this, but I don't have that much time and for 
some reason the compiler doesn't build on my machine right now (linker 
errors)...

I have no idea what's up with the visibility problems, as I haven't 
worked on that part of DMD's code, but probably there is a bad 
interaction between the code that checks for symbol visibility and 
`static foreach` loop variable scopes.