Stabilizing a subset of const generics

[withoutboats]

Summary

I want to propose that we get a subset const generics on track to stabilization in the near future. We should have a meeting to discuss the specifics and attempt to achieve consensus on this plan.

Background reading

• https://without.boats/blog/shipping-const-generics/
• https://internals.rust-lang.org/t/stabilizing-a-const-generics-mvp/12727/
• Stabilizable subset of const generics compiler-team#332

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.

[nikomatsakis]

As discussed on Zulip, we are thinking of doing this meeting this week, July 22 -- @withoutboats can you confirm availability for that slot?

[withoutboats]

Yes I plan to attend.

[nikomatsakis]

Scheduled for July 22 design meeting.

[nikomatsakis]

Minutes and recording are available: https://github.com/rust-lang/lang-team/blob/master/design-meeting-minutes/2020-07-22-Const-generics-MVP.md