compiler flag for "preview all"

[Max Samukha]

On Tuesday, 30 June 2020 at 19:55:40 UTC, Dennis wrote:

>
> nosharedaccess: tried it, but it gave some compile errors I 
> couldn't be bothered to fix
> rvaluerefparam: cool feature, but DIP is in 'GitHub gist' state 
> (not even draft review), so it's not certain this will actually 
> become part of the language
> dip1008: I don't need @nogc Exceptions it, from what I heard 
> it's in a buggy state
> dip1021: useless switch that gives 100% false positives (see 
> DIP review). I tried to enable it, it gave a compile error in 
> Phobos std.uni.CowArray, and ended in a dmd segfault

"-revert" could enable previously disabled previews: dmd 
-preview=enableAll -revert=1008,1021