...way suggesting we make this opt-out.

Making this opt-in gives us a ton...

https://issues.dlang.org/show_bug.cgi?id=24492

Adam D. Ruppe <destructionator@gmail.com...

...links to a discussion where Walter appears to be OK with opt-in write barriers.

...cgi?id=24492

          Issue ID: 24492
           Summary: Opt-in support for pointer write barriers
           Product...

...an excellent position to make write barriers opt-in, with different strategies allowing for different...

...situation.

We can have write barriers be opt-in, and if all binaries have it...

...write barriers. They are approved as an opt-in feature.

Nobody has added support nor...

...allowed to work on adding write barriers (opt-in) so a more advanced GC could...

...nonnull by default and allow people to opt out like in other languages, or do...

...how to annotate in an opt-in solution. (I think opt-in is absolutely required...