Toolchain 'nightly-x86_64-apple-darwin' missing from nightly 1.31.0 (de9666f12 2018-10-31)

[phansch]

This happens on Clippy's Travis CI:

info: syncing channel updates for 'nightly-x86_64-apple-darwin'
info: latest update on 2018-11-01, rust version 1.31.0-nightly (de9666f12 2018-10-31)
error: toolchain 'nightly-x86_64-apple-darwin' is not installed

https://travis-ci.org/rust-lang-nursery/rust-clippy/jobs/449198446#L87-L89

Rustup can't seem to find the toolchain It seems to be missing from the latest nightly: https://mexus.github.io/rustup-components-history/x86_64-apple-darwin.html

[kennytm]

Potentially caused by #55304

[kigawas]

On mac OS mojave

$ rustup update
info: syncing channel updates for 'stable-x86_64-apple-darwin'
info: syncing channel updates for 'nightly-x86_64-apple-darwin'
info: latest update on 2018-11-01, rust version 1.31.0-nightly (de9666f12 2018-10-31)
warning: component 'rustc' is not available anymore on target 'x86_64-apple-darwin'
warning: component 'rust-std' is not available anymore on target 'x86_64-apple-darwin'
warning: component 'cargo' is not available anymore on target 'x86_64-apple-darwin'
warning: component 'rust-docs' is not available anymore on target 'x86_64-apple-darwin'
warning: component 'rls-preview' is not available anymore on target 'x86_64-apple-darwin'
warning: component 'rust-src' is not available anymore
warning: component 'rust-analysis' is not available anymore on target 'x86_64-apple-darwin'
error: some components unavailable for download: 'rustc', 'cargo'
info: checking for self-updates

       stable-x86_64-apple-darwin unchanged - rustc 1.30.0 (da5f414c2 2018-10-24)
  nightly-x86_64-apple-darwin update failed - rustc 1.30.0-nightly (73c78734b 2018-08-05)