What are those circumstances? There are no stability guarantees for unstable features, so I don&#x27;t see how a nightly build that happens to correspond to a major version has value over any other nightly build. The stability you would get by sticking to &quot;1.6 + features&quot; seems precisely equal to the stability you would get from picking a recent nightly and sticking to that build.<p>It sounds to me like the real issue here is that procedural macros aren&#x27;t stable, not anything about the release process.