const_eval: update for const_mut_refs and const_refs_to_cell stabilization #1590

RalfJung · 2024-08-27T19:07:39Z

This is the reference PR accompanying rust-lang/rust#129195.

Fixes rust-lang/rust#57349
Fixes rust-lang/rust#80384

…ation

traviscross · 2024-08-27T20:58:18Z

src/const_eval.md

+* All forms of [borrow]s, including raw borrows, with one limitation:
+  mutable borrows and shared borrows to values with interior mutability
+  are only allowed to refer to *transient* places. A place is *transient*
+  if it will be deallocated before the end of evaluating the current constant item.


Given that not all const contexts are syntactically items, though they are desugared that way, would it be better here to say "end of evaluating the current constant context"?

If "evaluating a const context" is meaningful, then yeah that would work. It sounds a bit odd to me, how can you evaluate a "context"? The context is what the evaluation occurs in.

No strong preference either way.

Maybe "evaluating the contents of the current const context"? Open to other ideas.

The main thrust is that const context is something we define and seems to be closer to what we mean here.

"evaluating the item" is how we call it in the compiler so I got used to that one. ;)

ehuss

Thanks!

Update books ## rust-lang/book 5 commits in e7d217be2a75ef1753f0988d6ccaba4d7e376259..99cf75a5414fa8adbe3974bd0836661ca901708f 2024-09-23 16:18:39 UTC to 2024-09-11 18:38:03 UTC - translations: remove broken link (rust-lang/book#4036) - Update build instructions: include mdbook plugins (rust-lang/book#4032) - Add `cargo init` usage suggestion to 1.3 (rust-lang/book#4025) - Use immutable borrow of `TcpStream` when creating `BufReader` (rust-lang/book#4024) - Upgrade to Rust 1.81 (rust-lang/book#4031) ## rust-lang/edition-guide 1 commits in b3ca7ade0f87d7e3fb538776defc5b2cc4188172..c7ebae25cb4801a31b6f05353f6d85bfa6feedd1 2024-09-22 08:47:02 UTC to 2024-09-22 08:47:02 UTC - Update static_mut_refs now that it is a lint (rust-lang/edition-guide#322) ## rust-lang/reference 10 commits in 687faf9958c52116d003b41dfd29cc1cf44f5311..24fb2687cdbc54fa18ae4acf5d879cfceca77b2c 2024-09-22 09:07:12 UTC to 2024-09-10 19:24:17 UTC - do not talk about the 'address of a constant' (rust-lang/reference#1624) - Add spec identifier syntax to interior-mutability.md (rust-lang/reference#1585) - Add spec identifier syntax to input-format.md (rust-lang/reference#1584) - Document limitations on block doc comments (rust-lang/reference#1602) - Places based on misaligned pointers: also mention 'static's as a possible base for place projections (rust-lang/reference#1606) - type-layout: mention that call ABI compatibility is a separate concern (rust-lang/reference#1608) - stabilize `const_extern_fn` (rust-lang/reference#1596) - const_eval: update for const_mut_refs and const_refs_to_cell stabilization (rust-lang/reference#1590) - fix: unclosed tag `sup` (rust-lang/reference#1612) - Fix improper documentation on casting non_exhaustive enums (rust-lang/reference#1607) ## rust-lang/rustc-dev-guide 13 commits in 0ed9229f5b6f7824b333beabd7e3d5ba4b9bd971..555f3de2fa0d61c4294b74d245f1cbad6fcbf589 2024-09-23 12:51:33 UTC to 2024-09-10 07:32:10 UTC - chore: add missing `.` (rust-lang/rustc-dev-guide#2074) - Add remark on required free disk space (rust-lang/rustc-dev-guide#2073) - fix broken links (rust-lang/rustc-dev-guide#2063) - Add advice about submitting potentially hard-to-review PRs (rust-lang/rustc-dev-guide#2036) - Edit a sentence for clarity (rust-lang/rustc-dev-guide#2071) - Emphasize how to run a single tool test (rust-lang/rustc-dev-guide#2070) - Remove chalk is owned by WG-traits (rust-lang/rustc-dev-guide#2068) - Fix conditions lowering text for enums with no fields (rust-lang/rustc-dev-guide#2066) - update proof tree chapter (rust-lang/rustc-dev-guide#2054) - Add docs for JS tests (rust-lang/rustc-dev-guide#2048) - Reflect `x.py test`'s `--rustc-args` option being renamed to `--compiletest-rustc-args` (rust-lang/rustc-dev-guide#2062) - we standardized on this more reliable command (rust-lang/rustc-dev-guide#2061) - Fix Typo and Remove Outdated Line About C Variadics (rust-lang/rustc-dev-guide#2060)

Rollup merge of rust-lang#130759 - rustbot:docs-update, r=ehuss Update books ## rust-lang/book 5 commits in e7d217be2a75ef1753f0988d6ccaba4d7e376259..99cf75a5414fa8adbe3974bd0836661ca901708f 2024-09-23 16:18:39 UTC to 2024-09-11 18:38:03 UTC - translations: remove broken link (rust-lang/book#4036) - Update build instructions: include mdbook plugins (rust-lang/book#4032) - Add `cargo init` usage suggestion to 1.3 (rust-lang/book#4025) - Use immutable borrow of `TcpStream` when creating `BufReader` (rust-lang/book#4024) - Upgrade to Rust 1.81 (rust-lang/book#4031) ## rust-lang/edition-guide 1 commits in b3ca7ade0f87d7e3fb538776defc5b2cc4188172..c7ebae25cb4801a31b6f05353f6d85bfa6feedd1 2024-09-22 08:47:02 UTC to 2024-09-22 08:47:02 UTC - Update static_mut_refs now that it is a lint (rust-lang/edition-guide#322) ## rust-lang/reference 10 commits in 687faf9958c52116d003b41dfd29cc1cf44f5311..24fb2687cdbc54fa18ae4acf5d879cfceca77b2c 2024-09-22 09:07:12 UTC to 2024-09-10 19:24:17 UTC - do not talk about the 'address of a constant' (rust-lang/reference#1624) - Add spec identifier syntax to interior-mutability.md (rust-lang/reference#1585) - Add spec identifier syntax to input-format.md (rust-lang/reference#1584) - Document limitations on block doc comments (rust-lang/reference#1602) - Places based on misaligned pointers: also mention 'static's as a possible base for place projections (rust-lang/reference#1606) - type-layout: mention that call ABI compatibility is a separate concern (rust-lang/reference#1608) - stabilize `const_extern_fn` (rust-lang/reference#1596) - const_eval: update for const_mut_refs and const_refs_to_cell stabilization (rust-lang/reference#1590) - fix: unclosed tag `sup` (rust-lang/reference#1612) - Fix improper documentation on casting non_exhaustive enums (rust-lang/reference#1607) ## rust-lang/rustc-dev-guide 13 commits in 0ed9229f5b6f7824b333beabd7e3d5ba4b9bd971..555f3de2fa0d61c4294b74d245f1cbad6fcbf589 2024-09-23 12:51:33 UTC to 2024-09-10 07:32:10 UTC - chore: add missing `.` (rust-lang/rustc-dev-guide#2074) - Add remark on required free disk space (rust-lang/rustc-dev-guide#2073) - fix broken links (rust-lang/rustc-dev-guide#2063) - Add advice about submitting potentially hard-to-review PRs (rust-lang/rustc-dev-guide#2036) - Edit a sentence for clarity (rust-lang/rustc-dev-guide#2071) - Emphasize how to run a single tool test (rust-lang/rustc-dev-guide#2070) - Remove chalk is owned by WG-traits (rust-lang/rustc-dev-guide#2068) - Fix conditions lowering text for enums with no fields (rust-lang/rustc-dev-guide#2066) - update proof tree chapter (rust-lang/rustc-dev-guide#2054) - Add docs for JS tests (rust-lang/rustc-dev-guide#2048) - Reflect `x.py test`'s `--rustc-args` option being renamed to `--compiletest-rustc-args` (rust-lang/rustc-dev-guide#2062) - we standardized on this more reliable command (rust-lang/rustc-dev-guide#2061) - Fix Typo and Remove Outdated Line About C Variadics (rust-lang/rustc-dev-guide#2060)

Update books ## rust-lang/book 5 commits in e7d217be2a75ef1753f0988d6ccaba4d7e376259..99cf75a5414fa8adbe3974bd0836661ca901708f 2024-09-23 16:18:39 UTC to 2024-09-11 18:38:03 UTC - translations: remove broken link (rust-lang/book#4036) - Update build instructions: include mdbook plugins (rust-lang/book#4032) - Add `cargo init` usage suggestion to 1.3 (rust-lang/book#4025) - Use immutable borrow of `TcpStream` when creating `BufReader` (rust-lang/book#4024) - Upgrade to Rust 1.81 (rust-lang/book#4031) ## rust-lang/edition-guide 1 commits in b3ca7ade0f87d7e3fb538776defc5b2cc4188172..c7ebae25cb4801a31b6f05353f6d85bfa6feedd1 2024-09-22 08:47:02 UTC to 2024-09-22 08:47:02 UTC - Update static_mut_refs now that it is a lint (rust-lang/edition-guide#322) ## rust-lang/reference 10 commits in 687faf9958c52116d003b41dfd29cc1cf44f5311..24fb2687cdbc54fa18ae4acf5d879cfceca77b2c 2024-09-22 09:07:12 UTC to 2024-09-10 19:24:17 UTC - do not talk about the 'address of a constant' (rust-lang/reference#1624) - Add spec identifier syntax to interior-mutability.md (rust-lang/reference#1585) - Add spec identifier syntax to input-format.md (rust-lang/reference#1584) - Document limitations on block doc comments (rust-lang/reference#1602) - Places based on misaligned pointers: also mention 'static's as a possible base for place projections (rust-lang/reference#1606) - type-layout: mention that call ABI compatibility is a separate concern (rust-lang/reference#1608) - stabilize `const_extern_fn` (rust-lang/reference#1596) - const_eval: update for const_mut_refs and const_refs_to_cell stabilization (rust-lang/reference#1590) - fix: unclosed tag `sup` (rust-lang/reference#1612) - Fix improper documentation on casting non_exhaustive enums (rust-lang/reference#1607) ## rust-lang/rustc-dev-guide 13 commits in 0ed9229f5b6f7824b333beabd7e3d5ba4b9bd971..555f3de2fa0d61c4294b74d245f1cbad6fcbf589 2024-09-23 12:51:33 UTC to 2024-09-10 07:32:10 UTC - chore: add missing `.` (rust-lang/rustc-dev-guide#2074) - Add remark on required free disk space (rust-lang/rustc-dev-guide#2073) - fix broken links (rust-lang/rustc-dev-guide#2063) - Add advice about submitting potentially hard-to-review PRs (rust-lang/rustc-dev-guide#2036) - Edit a sentence for clarity (rust-lang/rustc-dev-guide#2071) - Emphasize how to run a single tool test (rust-lang/rustc-dev-guide#2070) - Remove chalk is owned by WG-traits (rust-lang/rustc-dev-guide#2068) - Fix conditions lowering text for enums with no fields (rust-lang/rustc-dev-guide#2066) - update proof tree chapter (rust-lang/rustc-dev-guide#2054) - Add docs for JS tests (rust-lang/rustc-dev-guide#2048) - Reflect `x.py test`'s `--rustc-args` option being renamed to `--compiletest-rustc-args` (rust-lang/rustc-dev-guide#2062) - we standardized on this more reliable command (rust-lang/rustc-dev-guide#2061) - Fix Typo and Remove Outdated Line About C Variadics (rust-lang/rustc-dev-guide#2060)

const_eval: update for const_mut_refs and const_refs_to_cell stabiliz…

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…ation

This was referenced Aug 27, 2024

Tracking Issue for const_refs_to_cell rust-lang/rust#80384

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Tracking issue for &mut T in const contexts (const_mut_refs) rust-lang/rust#57349

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traviscross reviewed Aug 27, 2024

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ehuss added the S-waiting-on-stabilization Waiting for a stabilization PR to be merged in the main Rust repository label Aug 27, 2024

talk about const contexts, not const items

ace105a

RalfJung force-pushed the const-mut-refs branch from aa1dab6 to ace105a Compare August 28, 2024 05:53

traviscross approved these changes Aug 28, 2024

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ehuss approved these changes Sep 15, 2024

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ehuss added this pull request to the merge queue Sep 15, 2024

Merged via the queue into rust-lang:master with commit 8da7b2a Sep 15, 2024
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Rust unstable features needed for the kernel Rust-for-Linux/linux#2

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const_eval: update for const_mut_refs and const_refs_to_cell stabilization #1590

const_eval: update for const_mut_refs and const_refs_to_cell stabilization #1590

RalfJung commented Aug 27, 2024 •

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const_eval: update for const_mut_refs and const_refs_to_cell stabilization #1590

const_eval: update for const_mut_refs and const_refs_to_cell stabilization #1590

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