> The Rust compiler is not known for being stable, as people apparently
> very rarely use only the ``stable'' features of the compiler.
If
what you need is stability, you should use the stable branch, which is,
for that matter, the one that is installed by default.
I will add that I have used several rust-based packages over the last several years, both as part of dabbling a bit with the language's unusual features and as part of a decades long side-interest in reimplementations of the Unix/Posix "standard user and developer toolset" (that started with getting GNU on early SVR4 systems and has also included "rewrite everything in perl", at least 4 different versions of unix-y toolchain for Windows, 3 of same for macOS, and busybox). I've never used the nightly (or beta) toolchain for any of these, and have never needed to do so.
I hope that helps,
~Chad