Design Meeting: Field Projection

[y86-dev]

Summary

The topic of this design meeting is the field projection RFC. The goals are:

• finding a suitable API to express field projection,
• discern the extent of such projections (i.e. are projections on iterators allowed?),

Background reading

• the RFC: RFC: Field projection rfcs#3318
• pre-RFC discussion: https://internals.rust-lang.org/t/pre-rfc-field-projection/17383/57

About this issue

This issue corresponds to a lang-team design meeting proposal. It corresponds to a possible topic of discussion that may be scheduled for deeper discussion during one of our design meetings.

[y86-dev]

As I am pretty short on time this month, I would prefer it if the meeting takes place in march or later.

[joshtriplett]

@y86-dev Would you propose that the design meeting use the RFC itself as a design document, or do you intend to write and provide a design document that has more focused design questions or similar?

At a minimum, it would be helpful to have a set of questions you'd like the lang team to focus on when looking at this.

[tmandry]

Here are some guidelines on design documents from #191 (comment):

We're going to take a stab at better doc guidelines, but here are a few docs from past meetings that were productive:

• https://github.com/rust-lang/lang-team/blob/master/design-meeting-minutes/2021-10-13-where-the-where.md
• https://github.com/rust-lang/lang-team/blob/master/design-meeting-minutes/2022-10-05-provenance.md

Key point is to identify clearly the topics to discuss (and, often, what not to discuss) and to give the background needed for that.

Note that the docs include minutes of the actual converations and questions that happened -- best thing is to author the doc in hackmd so we can live edit it during the meeting.

One particular danger is that sometimes docs get too in the weeds with details, where really what is needed from the lang team is more alignment around the high-level goals, or which design features should be prioritized (i.e., the question is not "do we do X or Y" it's "which use case is more important").

[y86-dev]

I intent to write a design document that outlines the core problem and the desired properties of a solution (these would also be a discussion point). Thanks for the links, I will take them into account when writing.

[nikomatsakis]

Scheduled for Mar 29

[tmandry]

This meeting happened. Doc link: https://hackmd.io/@y86-dev/SkkfRkzWh