-preview=in might break code

[Iain Buclaw]

On Monday, 5 October 2020 at 12:04:51 UTC, Andrei Alexandrescu 
wrote:
>
> So now it's up to us to decide whether we want less of that or 
> more of that.

There are a number of NRVO tests that I've fixed up in the 
testsuite because one type that is passed in memory on x86_64 is 
passed in registers on SPARC64.  Or the DMD x86_64 ABI was at the 
time incomplete and wrongly passed a certain type in memory. :-)