Rollup of 9 pull requests#64658

Merged

bors merged 23 commits intorust-lang:masterfrom

Centril:rollup-9s3raz6

Sep 21, 2019

Commits on Sep 11, 2019

Stabilize `param_attrs` in Rust 1.39.0
c410-f3r
committed

Commits on Sep 12, 2019

Commits on Sep 16, 2019

Document `From` trait for `LhsExpr`
crgl
committed

Commits on Sep 19, 2019

Commits on Sep 20, 2019

Commits on Sep 21, 2019