Incremental garbage collection

[Elronnd]

On Friday, 21 January 2022 at 12:26:42 UTC, Ola Fosheim Grøstad 
wrote:
> It could, in theory, if you change the semantics of @nogc and 
> annotate everything with @nogc that the collector must leave 
> alone.

You do not.  See my other post where I clarified what I meant 
with this approach.

> You also need to prevent scannable pointers to be available 
> through unions

You do not.  You do need to do _something_ about unions, but you 
do need to disallow pointers in them.  The spec says to pin 
objects which are in unions, which is a perfectly acceptable 
solution.  There are also cleverer solutions which violate that 
clause of the spec but do not break any actual code.

> There is also no way for D to force barriers on linked code, 
> hence the need for a breaking language level change at some 
> level.

You can do it with name mangling.  D is not binary compatible 
between releases.

------------------------------------

Bottom line: no source-level changes are necessary.