rustup: update to nightly-2023-11-26.

[LegNeato]

No description provided.

[eddyb]

^{Sorry for not looking at this sooner (please ping me on Discord, though I am in the process of trying to find a way to work around GitHub notifications being unusably bad, it's becoming untenable).}

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Anyway, this is far too recent, you should look on https://forge.rust-lang.org/ for "Will branch from master on".

The current nightly before this PR (2023-09-30) matches 1.74's branch-off date (September 29 2023) "plus one day" (to account for nightly-vs-git).

And if you look at past releases, they all followed that pattern, since 0.4 which introduced it, and IIRC even documents it (0.10 has just been delayed due to nothing being finished enough to warrant a release, sadly).

The next viable date is 1.75 that is, releasing Rust-GPU (just) after December 28 2023 using the nightly after the branch-off date of November 10 2023 (so 2023-11-11).

The nightly you chose if half-way during 1.76's development cycle and requires waiting for at least February next year for a Rust-GPU release.

(the PR is still useful, just not applicable any time soon)

[LegNeato]

Ah, I thought you were just updating adhoc. If rust-gpu requires nightly, is there a compelling reason to tie it to cutpoints? Perhaps my mental model is wrong about what versions are used where w.r.t rust-gpu and end users. In my mind when folks are using nightly the whole point is to stay close to HEAD...an "old" nightly is the worst of both worlds (not "stable" / tested, not recent).

Tracking HEAD would also make breakages and changes from rustc show up right away and they would more likely be treated as a regression. My impression is that often rust-gpu will be broken, and then weeks down the line you point it out to rustc. By that time the change has stuck and the onus is on you to convince them to revert(when it should be on them to prove that it should stay in and not treated as a regression).

Regardless, it might be worth setting up a CI job that updates to the most recent nightly and tries to build rust-gpu automatically to catch issues as they are introduced.

[LegNeato]

Ok, for now I am going to just keep updating #1109. Closing this.