compiler flag for "preview all"

[Mathias LANG]

On Monday, 29 June 2020 at 23:31:16 UTC, Bruce Carneal wrote:
> One of the ideas floated at beerconf was that of a single 
> compiler flag activating all "preview" options.  [...]
>
> The ldc and dmd documentation say that the preview=all flag 
> will list all available preview options, but in my testing both 
> ldc 1.22.0 and dmd 2.091.1 treat preview=all as an error. [...]

It was always intended to work this way, but it seems to have 
broken at some point.
Well, next release: https://github.com/dlang/dmd/pull/11348