Protected module members -- regression?

[Stanislav Blinov]

On Monday, 29 October 2018 at 10:47:11 UTC, Jonathan M Davis 
wrote:

> Really, if you want to know, the surest way is to test older 
> versions of the compiler. Someone may post that they remember 
> it being an error in the past, but I doubt that they could give 
> you a compiler version if they did, and honestly, it's the sort 
> of thing that most of us would never have tried, since it makes 
> no sense to use protected outside of a class.

Easy enough. The latest version to *not* issue even a warning was 
2.070.2. Mike's code compiles quite happily. Starting with 
2.071.0, the compiler starts issuing a warning about visibility. 
Going by the changelogs, I think this is the most probable cause:

https://dlang.org/changelog/2.071.0.html#dip22
https://wiki.dlang.org/DIP22