Abbreviation for zero-sized types with particular alignment

[gnzlbg]

We often need to talk about zero-sized types (ZSTs) with a particular alignment requirement, e.g., 1, or in general, N:

#[repr(align(N))] struct Zst;

It was suggested in #164 (comment) that we should have an abbreviation for this defined in the glossary, where we also define the zero-sized type (ZST) abbreviation, to avoid writing "a zero-sized one-aligned type" and similar constructs all over the place.

A proposal was to use the N-ZST schema for an "N-aligned zero-sized type", e.g., 1-ZST would stand for a "one-aligned zero-sized type".

[JohnScience]

N-ZST is a great name for talking about the concept in natural language, yet it has a great deficiency. Its particular instances, such as 4-ZST or 16-ZST, cannot be identifiers. aligned crate used A1, A2...A64 as names for 1-ZST ..= 64-ZST. I'm unsure whether I should change the name of A1 to, let's say, A1ZST. The latter may seem cryptic to the outsider.

[RalfJung]

Alternatively you could use ZST4 etc, which avoids the cryptic A?

[JohnScience]

Alternatively you could use ZST4 etc, which avoids the cryptic A?

I believe that's the best approach. The original author of aligned crate didn't make promises about A1 being ZST, so there even might be no confusion.