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Predrag Gruevski
@predr.ag

I'm taking a few days off from work, let's see how far I can get with having cargo-semver-checks scan the Rust standard library for accidental breakage... Idea courtesy of a random hallway conversation with @amanieu.bsky.social at the Rust All Hands part of @rustnl.bsky.social this year.

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Predrag Gruevski
@predr.ag

It's Tuesday, and so far so good! Two things happened today, by which I mean after midnight last night. First, I merged a PR to allow unstable stdlib items to be considered non-public-API. Similarly, const-unstable items are considered non-const in public API: github.com/obi1kenobi/t...

github.comAllow std library stability to influence what is public API. by obi1kenobi · Pull Request #1080 · obi1kenobi/trustfall-rustdoc-adapterIn preparation for allowing cargo-semver-checks to check the Rust standard library for accidental breakage, add a mode where stability affects what is considered public API. In that mode: unstable...
Predrag Gruevski
@predr.ag

Second, the last required upstream PR got merged into rustdoc! It lets us know which default values (like on associated consts, or default method impls in traits) are considered stable and therefore public API. This is the last "partial stability" mechanism we need. github.com/rust-lang/ru...

github.comInclude default-stability info in rustdoc JSON. by obi1kenobi · Pull Request #158468 · rust-lang/rustAdd a default_unstable field on associated constants, associated types, and functions. The field is populated only when those items appear inside a trait, only when there's a default present, a...
Predrag Gruevski
@predr.ag

It's Wednesday, day 3. Default-stability is in rustdoc JSON in today's nightly Rust. Only *stable* defaults are public API, so we pretend unstable values don't exist. I'm working on a PR for this, and also on type normalization improvements to let us have type-checking lints 👀

Predrag Gruevski
@predr.ag

I had to take a brief detour to triage a surprising new class of SemVer breakage. It's always *a time* when the net result is "8 issues across 5 repos" 😅 The net result is the same: even more lints! github.com/obi1kenobi/c...

github.comBreakage in items of reachable but not nameable supertrait · Issue #1658 · obi1kenobi/cargo-semver-checksExample minified from time-rs/time#793 mod sealed { pub trait Sealed { fn example(&self) { ... } } } pub trait Visible: sealed::Sealed {} Now modify: mod sealed { pub trait Sealed { - fn example(&s...