core::slice::SliceExt removed in 1.27 beta

[pietroalbini]

The core::slice::SliceExt trait was removed from the libcore public API in 1.27 beta, but it contained some stable methods in it, and it was possible to call them on stable. Its removal is breaking some crates.

Playground example

• snes-bitplanes regressed from stable to beta (build log) cc @TooManyBees

The cause is probably #49896, cc @SimonSapin @alexcrichton

[kennytm]

This is expected: TooManyBees/super-metroid#1

[SimonSapin]

As @kennytm said this particular build failure did come up in a pre-landing Crater run but was the only one that seemed "legit", and I submitted PR to make the code compile both before and after the change.

[pietroalbini]

Sure. Marking this as "won't fix" then.