Rollup of 7 pull requests#57957

Merged

bors merged 25 commits intorust-lang:masterfrom

Jan 29, 2019

Commits on Jan 3, 2019

Extend E0106, E0261
purple-ice
authored

Commits on Jan 4, 2019

Fix changes for E0106, E0261
purple-ice
authored

Commits on Jan 16, 2019

Avoid erase_regions_ty queries if there are no regions to erase
dotdash
committed

Commits on Jan 22, 2019

Print a slightly clearer message when failing to spawn a thread
Jethro Beekman
committed

Commits on Jan 23, 2019

Fix invalid background color
GuillaumeGomez
committed

Commits on Jan 26, 2019

Pretty print `$crate` as `crate` or `crate_name` in more cases
petrochenkov
committed

Commits on Jan 28, 2019