Backport rust-lang/rust-analyzer#20056 and rust-lang/rust-analyzer#20100

[Veykril]

#20056 and #20100

[ShoyuVanilla]

I don't know the context. Should we revert them due to some regressions or rustc changes?

[Veykril]

No, these PRs fix things upstream that live on the beta branch, but the PRs themselves didn't make it onto the beta branch. That is using beta rust-analyzer on the beta toolchain sources still shows errors. We need to commit the PR diffs onto upstream's beta branch (do a beta backport for them). That is we fixed these things too late as the sync didn't make it before the beta branchoff.

[ChayimFriedman2]

Also need to backport #20073 then.

[ShoyuVanilla]

Closed with rust-lang/rust#143794