Are our previews not tested for compatibility?

It kinda feels like preview features should surely get tested, such that we know the preview represents a valid feature...

On Tue, 13 Aug 2024 at 20:46, Nicholas Wilson via Digitalmars-d <digitalmars-d@puremagic.com> wrote:

On Tuesday, 13 August 2024 at 09:11:22 UTC, Nicholas Wilson wrote:
> On Tuesday, 13 August 2024 at 04:23:15 UTC, Manu wrote:
>> So this preview has been available for more than 5 years.
>> Can we un-preview this now?
>
> https://github.com/dlang/dmd/pull/16778

at the moment, no because it doesn't pass CI. Templates with `ref
T` with `T==void` (misrecognised untyped lambdas e.g. `str =>
dst.put(str)` which should be a delegate) give e.g.:
std/bigint.d(1280): Error: cannot have parameter of type
`void`