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One question towards maturity: has any working version of the Rust compiler ever existed? By which I mean one that successfully upholds the memory-safety guaran

One question towards maturity: has any working version of the Rust compiler ever existed? By which I mean one that successfully upholds the memory-safety guarantees Rust is supposed to make, and does not have any "soundness holes" (which IIRC were historically used as a blank check / excuse to break backwards compatibility). The current version of the Rust compiler definitely doesn't -- there's known issues like https://github.com/rust-lang/rust/issues/57893 https://github.com/rust-lang/rust/issues/57893 -- but maybe there's some historical version from before the features that caused those problems were introduced.

steveklabnik 1y ago
Every compiler has soundness bugs. They’re just programs like any other. This isn’t exclusive to Rust.
- csande17 1y ago
  In general, the way Rust blurs the line between "bugs in the compiler" and "problems with how the language is designed" seems pretty harmful and misleading. But it's also a core part of the marketing strategy, so...
  - deleted 1y ago
    [deleted]
  - steveklabnik 1y ago
    What makes you say this is a core part of the marketing strategy? I don’t think Rust’s marketing has ever focused on compiler bugs or their absence.
    - csande17 1y ago
      You are correct that Rust's marketing does not claim that there are no bugs in its compiler. In fact it does the opposite: it suggests that there are no problems with the language, by asserting that any observed issue in the language is actually a bug in the compiler. Like, in the C world, there's a difference between "the C specification has problems" and "GCC incorrectly implements the C specification". You can make statements about what "the C language" does or doesn't guarantee independently of any specific implementation. But "the Rust language" is not a specification. It's just a vague ideal of things the Rust team is hoping their compiler will be able to achieve. And so "the Rust language" gets marketed as e.g. having a type system that guarantees memory safety, when in fact no such type system has been designed -- the best we have is a compiler with a bunch of soundness holes. And even if there's some fundamental issue with how traits work that hasn't been resolved for six years, that can get brushed off as merely a compiler bug. This propagates down into things like Rust's claims about backwards compatibility. Rust is only backwards-compatible if your programs are written in the vague-ideal "Rust language". The Rust compiler, the thing that actually exists in the real world, has made a lot of backwards-incompatible changes. But these are by definition just bugfixes, because there is no such thing as a design issue in "the Rust language", and so "the Rust language" can maintain its unbroken record of backwards-compatibility.
      - aw1621107 1y ago
        > And even if there's some fundamental issue with how traits work that hasn't been resolved for six years, that can get brushed off as merely a compiler bug. Is it getting brushed off as merely a compiler bug? At least if I'm thinking of the same bug as you [0] the discussion there seems to be more along the lines of the devs treating it as a "proper" language issue, not a compiler bug. At least as far as I can tell there hasn't been a resolution to the design issue, let alone any work towards implementing a fix in the compiler. The soundness issue that I see more frequently get "brushed off as merely a compiler bug" is the lifetime variance one underpinning cve-rs [1], which IIRC the devs have long decided what the proper behavior should be but actually implementing said behavior is blocked behind some major compiler reworks. > has made a lot of backwards-incompatible changes Not sure I've seen much evidence for "a lot" of compatibility breaks outside of the edition system. Perhaps I'm just particularly (un)lucky? > because there is no such thing as a design issue in "the Rust language" I'm not sure any of the Rust devs would agree? Have any of them made a claim along those lines? [0]: https://github.com/rust-lang/rust/issues/57893 https://github.com/rust-lang/rust/issues/57893 [1]: https://github.com/Speykious/cve-rs https://github.com/Speykious/cve-rs
        csande17 1y ago
        > Is it getting brushed off as merely a compiler bug? Yes, this thread contains an example: https://news.ycombinator.com/item?id=45587209 https://news.ycombinator.com/item?id=45587209 . (I linked the same bug you did in the comment that that's a reply to.) The Rust team may see this as a language design issue internally, and I'd be inclined to agree. Rust's outward-facing marketing does not reflect this view.
        aw1621107 1y ago
        > I linked the same bug you did in the comment that that's a reply to Ah, my apologies. Not sure exactly how I managed to miss that. That being said, I guess I might have read that bit of your comment different than you had in mind; I was thinking of whether the Rust devs were dismissing language design issues as compiler bugs, not what third parties (albeit one with an unusually relevant history in this case) may think. > Rust's outward-facing marketing does not reflect this view. As above, perhaps I interpret the phrase "outward-facing marketing" differently than you do. I typically associate that (and "marketing" in general, in this context) with more official channels, whether that's official posts or posts by active devs in an official capacity.
dathinab 1y ago
has there ever been a modern optimizing C compiler free of pretty serious bugs? (it's a rhetoric question, there hasn't been any)

steveklabnik 1y ago

Every compiler has soundness bugs. They’re just programs like any other. This isn’t exclusive to Rust.

csande17 1y ago
In general, the way Rust blurs the line between "bugs in the compiler" and "problems with how the language is designed" seems pretty harmful and misleading. But it's also a core part of the marketing strategy, so...
- deleted 1y ago
  [deleted]
- steveklabnik 1y ago
  What makes you say this is a core part of the marketing strategy? I don’t think Rust’s marketing has ever focused on compiler bugs or their absence.
  - csande17 1y ago
    You are correct that Rust's marketing does not claim that there are no bugs in its compiler. In fact it does the opposite: it suggests that there are no problems with the language, by asserting that any observed issue in the language is actually a bug in the compiler. Like, in the C world, there's a difference between "the C specification has problems" and "GCC incorrectly implements the C specification". You can make statements about what "the C language" does or doesn't guarantee independently of any specific implementation. But "the Rust language" is not a specification. It's just a vague ideal of things the Rust team is hoping their compiler will be able to achieve. And so "the Rust language" gets marketed as e.g. having a type system that guarantees memory safety, when in fact no such type system has been designed -- the best we have is a compiler with a bunch of soundness holes. And even if there's some fundamental issue with how traits work that hasn't been resolved for six years, that can get brushed off as merely a compiler bug. This propagates down into things like Rust's claims about backwards compatibility. Rust is only backwards-compatible if your programs are written in the vague-ideal "Rust language". The Rust compiler, the thing that actually exists in the real world, has made a lot of backwards-incompatible changes. But these are by definition just bugfixes, because there is no such thing as a design issue in "the Rust language", and so "the Rust language" can maintain its unbroken record of backwards-compatibility.
    - aw1621107 1y ago
      > And even if there's some fundamental issue with how traits work that hasn't been resolved for six years, that can get brushed off as merely a compiler bug. Is it getting brushed off as merely a compiler bug? At least if I'm thinking of the same bug as you [0] the discussion there seems to be more along the lines of the devs treating it as a "proper" language issue, not a compiler bug. At least as far as I can tell there hasn't been a resolution to the design issue, let alone any work towards implementing a fix in the compiler. The soundness issue that I see more frequently get "brushed off as merely a compiler bug" is the lifetime variance one underpinning cve-rs [1], which IIRC the devs have long decided what the proper behavior should be but actually implementing said behavior is blocked behind some major compiler reworks. > has made a lot of backwards-incompatible changes Not sure I've seen much evidence for "a lot" of compatibility breaks outside of the edition system. Perhaps I'm just particularly (un)lucky? > because there is no such thing as a design issue in "the Rust language" I'm not sure any of the Rust devs would agree? Have any of them made a claim along those lines? [0]: https://github.com/rust-lang/rust/issues/57893 https://github.com/rust-lang/rust/issues/57893 [1]: https://github.com/Speykious/cve-rs https://github.com/Speykious/cve-rs
      - csande17 1y ago
        > Is it getting brushed off as merely a compiler bug? Yes, this thread contains an example: https://news.ycombinator.com/item?id=45587209 https://news.ycombinator.com/item?id=45587209 . (I linked the same bug you did in the comment that that's a reply to.) The Rust team may see this as a language design issue internally, and I'd be inclined to agree. Rust's outward-facing marketing does not reflect this view.
        aw1621107 1y ago
        > I linked the same bug you did in the comment that that's a reply to Ah, my apologies. Not sure exactly how I managed to miss that. That being said, I guess I might have read that bit of your comment different than you had in mind; I was thinking of whether the Rust devs were dismissing language design issues as compiler bugs, not what third parties (albeit one with an unusually relevant history in this case) may think. > Rust's outward-facing marketing does not reflect this view. As above, perhaps I interpret the phrase "outward-facing marketing" differently than you do. I typically associate that (and "marketing" in general, in this context) with more official channels, whether that's official posts or posts by active devs in an official capacity.

dathinab 1y ago

has there ever been a modern optimizing C compiler free of pretty serious bugs? (it's a rhetoric question, there hasn't been any)