Rollup of 4 pull requests#91090

Closed

matthiaskrgr wants to merge 9 commits intorust-lang:masterfrom

matthiaskrgr:rollup-pq67ylv

Commits on Oct 10, 2021

Mark `Arc::from_inner` / `Rc::from_inner` as unsafe
sdroege
committed

Commits on Nov 18, 2021

Use more let_else in rustc_mir_build
est31
committed

Commits on Nov 20, 2021