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ptr::eq: clarify that comparing dyn Trait is fragile #103567
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Hey! It looks like you've submitted a new PR for the library teams! If this PR contains changes to any Examples of
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r? @thomcc (rust-highfive has picked a reviewer for you, use r? to override) |
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Thanks!
@bors r+ rollup |
@bors r+ |
ptr::eq: clarify that comparing dyn Trait is fragile Also remove the dyn trait example from `ptr::eq` since those tests are not actually guaranteed to pass due to how unstable vtable comparison is. Cc `@rust-lang/libs-api` Cc discussion following rust-lang#80505
Rollup of 10 pull requests Successful merges: - rust-lang#103432 (rustdoc: don't mark Box<T> as Iterator, Read, etc) - rust-lang#103526 (More dupe typos again) - rust-lang#103537 (rustdoc: combine shared CSS between `.*-line-numbers`) - rust-lang#103549 (llvm-16: Don't initialize removed legacy passes) - rust-lang#103558 (Update cargo) - rust-lang#103567 (ptr::eq: clarify that comparing dyn Trait is fragile) - rust-lang#103579 (:arrow_up: rust-analyzer) - rust-lang#103580 (Fix typo in docs for `guaranteed_ne`) - rust-lang#103596 (thread::set_name: debug-assert that things went well) - rust-lang#103598 (rustc_lexer::TokenKind improve docs) Failed merges: - rust-lang#103585 (Migrate source line numbers CSS to CSS variables) r? `@ghost` `@rustbot` modify labels: rollup
I wonder if some of the documentation changes here for This PR references #80505 which notably appeared to agree that In other words Since pull request #80505 was closed (I think just because the patch wasn't updated according to feedback) I recently opened #103763 to keep track of the original issue about the If the same conclusion as from #80505 is confirmed for #103763 then it would probably make sense to further iterate the Arc and Rc documentation to somehow clarify that the On the other hand if it's decided that |
@@ -1733,6 +1733,12 @@ pub(crate) unsafe fn align_offset<T: Sized>(p: *const T, a: usize) -> usize { | |||
/// by their address rather than comparing the values they point to | |||
/// (which is what the `PartialEq for &T` implementation does). | |||
/// | |||
/// When comparing wide pointers, both the address and the metadata are tested for equality. | |||
/// However, note that comparing trait object pointers (`*const dyn Trait`) is unrealiable: pointers |
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typo: unrealiable -> unreliable
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Good catch! #105474
Rollup of 10 pull requests Successful merges: - rust-lang#103432 (rustdoc: don't mark Box<T> as Iterator, Read, etc) - rust-lang#103526 (More dupe typos again) - rust-lang#103537 (rustdoc: combine shared CSS between `.*-line-numbers`) - rust-lang#103549 (llvm-16: Don't initialize removed legacy passes) - rust-lang#103558 (Update cargo) - rust-lang#103567 (ptr::eq: clarify that comparing dyn Trait is fragile) - rust-lang#103579 (:arrow_up: rust-analyzer) - rust-lang#103580 (Fix typo in docs for `guaranteed_ne`) - rust-lang#103596 (thread::set_name: debug-assert that things went well) - rust-lang#103598 (rustc_lexer::TokenKind improve docs) Failed merges: - rust-lang#103585 (Migrate source line numbers CSS to CSS variables) r? `@ghost` `@rustbot` modify labels: rollup
600: Pull changes from upstream `master` r=kirtchev-adacore a=pietroalbini * rust-lang/rust#103605 * rust-lang/rust#103604 * rust-lang/rust#103598 * rust-lang/rust#103596 * rust-lang/rust#103580 * rust-lang/rust#103579 * rust-lang/rust#103567 * rust-lang/rust#103558 * rust-lang/rust#103549 * rust-lang/rust#103537 * rust-lang/rust#103526 * rust-lang/rust#103432 * rust-lang/rust#103571 * rust-lang/rust#103492 * rust-lang/rust#103572 * rust-lang/rust#103554 * rust-lang/rust#103546 * rust-lang/rust#103543 * rust-lang/rust#103428 * rust-lang/rust#102706 * rust-lang/rust#95710 * rust-lang/rust#103284 * rust-lang/rust#103562 * rust-lang/rust#103542 * rust-lang/rust#103536 * rust-lang/rust#103533 * rust-lang/rust#103520 * rust-lang/rust#103444 * rust-lang/rust#103430 * rust-lang/rust#103416 * rust-lang/rust#103287 * rust-lang/rust#103209 * rust-lang/rust#102951 * rust-lang/rust#103279 * rust-lang/rust#103158 Co-authored-by: Lukas Wirth <lukastw97@gmail.com> Co-authored-by: Pietro Albini <pietro.albini@ferrous-systems.com> Co-authored-by: DropDemBits <r3usrlnd@gmail.com> Co-authored-by: bors <bors@rust-lang.org> Co-authored-by: Pietro Albini <pietro@pietroalbini.org>
Also remove the dyn trait example from
ptr::eq
since those tests are not actually guaranteed to pass due to how unstable vtable comparison is.Cc @rust-lang/libs-api
Cc discussion following #80505