Auto merge of #40995 - alexcrichton:beta-next, r=alexcrichton
Backport PRs to beta
Backport of
* https://github.com/rust-lang/rust/pull/40967
* https://github.com/rust-lang/rust/pull/40836
* https://github.com/rust-lang/rust/pull/40779
* https://github.com/rust-lang/rust/pull/40888
Also includes a cargo submodule update