const-eval and future-[in]compat

[pnkfelix]

Meeting proposal info

• Title: const-eval and future-compat
• Type: technical

Summary

rust-lang/rust#99923 is currently affecting the 1.64-beta. Basically, a change (a soundness fix, to be clear) caused breakage to some amount of existing code (we believe it to be a small amount of existing code, thus impact will be small we think). We should figure out if we are going to try to put any further measures in place to deal with it before the 1.64 release goes out.

Separately, we should also talk about whether we want to invest in long-term changes to the CTFE/Miri architecture/interface to make it easier to address future instances of similar problems.

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[pnkfelix]

This meeting happened (zulip); we learned a lot and it culminated in the blog post at rust-lang/blog.rust-lang.org#1028