For a language with a pretty usable nightly, it sure would be nice if `rustup update` told you when the last nightly built fully rather than just failing to do any updates when components are missing from last night's build.
Currently manually browsing to https://mexus.github.io/rustup-components-history/x86_64-pc-windows-msvc.html to find the date I need to request an install of (even then, rustup creates a second toolchain install rather than updating my copy of nightly as giving a date to update enacts `toolchain install` behaviour).
So this is now getting fixed-fixed: https://github.com/rust-lang/rustup.rs/pull/1997
(Previously it was patched to explain to users how to manually find the last working build & install it - something the error message didn't make clear back in Feb was the expected process.)