Rollup of 8 pull requests#81385

Closed

jonas-schievink wants to merge 21 commits into

rust-lang:masterfrom

jonas-schievink:rollup-bqpuase

Commits on Jan 10, 2021

Commits on Jan 18, 2021

Commits on Jan 22, 2021

Make more traits of the From/Into family diagnostic items
flip1995
committed

Commits on Jan 24, 2021

codegen: assume constants cannot fail to evaluate
RalfJung
committed

Commits on Jan 25, 2021