Auto merge of #51717 - Mark-Simulacrum:snap, r=alexcrichton

Bootstrap from 1.28.0 beta

diff --cc src/liballoc/lib.rs
Simple merge

diff --cc src/libcore/slice/mod.rs
Simple merge

diff --cc src/librustc/lib.rs
Simple merge

diff --cc src/librustc_save_analysis/lib.rs
Simple merge