TypeInfo in struct ABI

[Teodor Dutu]

On Monday, 17 January 2022 at 15:36:28 UTC, max haughton wrote:
> What do you mean by ABI here?

I simply meant that the TypeInfo object is written inside the 
struct object itself.

> This sounds like a detail of how the GC allocates memory rather 
> than the ABI strictly - it's certainly not specified under 
> "struct" in the ABI document.

I understand this now, but one of the goals of replacing the old 
druntime hooks with templates is using `TypeInfo` as little as 
possible. Therefore, the essence of my question is: Can we do 
`_d_newitemU` without `TypeInfo`, without negatively impacting 
the GC?