Rollup of 16 pull requests#78421

Merged

bors merged 34 commits intorust-lang:masterfrom

JohnTitor:rollup-bq2d7fo

Oct 27, 2020

Commits on Oct 4, 2020

Add [T]::as_chunks_mut (as unstable)
scottmcm
committed

Commits on Oct 21, 2020

allow using the system-wide llvm-libunwind as the unwinder
Keruspe
committed

Commits on Oct 22, 2020

Prefer to use `print_def_path`
JohnTitor
committed

Commits on Oct 23, 2020

Add test for bad NLL higher-ranked subtype
Aaron1011
committed

Commits on Oct 26, 2020