What's the deal with the massive duplication in std.meta?

[Walter Bright]

On 5/2/2021 4:55 AM, Andrei Alexandrescu wrote:
> On 5/1/21 6:26 AM, Nick Treleaven wrote:
>> On Saturday, 1 May 2021 at 10:23:26 UTC, Nick Treleaven wrote:
>>> I made a dmd pull to fix that bug, but I wasn't too confident about its 
>>> correctness, and the fix didn't get merged.
>>
>> https://github.com/dlang/dmd/pull/11320
> 
> Thanks! This is important work.
> 
> I see Iain mentioned it breaks existing behavior. What is the policy for 
> breaking broken behavior? We shouldn't deprecate it, but there should be a 
> compatibility switch or something.
> 
> Walter, what's the plan here?

It's definitely a bug and needs fixing.

The idea is to correctly diagnose any code that breaks, suggesting the user fix 
it or use the revert switch.