Implement pinned drop sugar by P8L1 · Pull Request #156452 · rust-lang/rust

P8L1 · 2026-05-11T12:56:22Z

Implements fn drop(&pin mut self) as sugar for Drop::pin_drop.

The resolver recognizes fn drop(&pin mut self) syntactically in trait impls and performs lookup using the effective pin_drop name. AST lowering independently rechecks the syntactic sugar, validates that the resolved item belongs to the actual Drop lang trait, and emits HIR with ident pin_drop for accepted sugar. Existing type checking, Drop validation, drop glue, and direct-call checks remain unchanged.

Drop identity is checked during AST lowering through tcx.lang_items().drop_trait(), after resolver has performed the effective pin_drop lookup. The resolver does not need to know whether the trait is the actual Drop lang item, and it no longer passes marked impl item IDs to lowering.

This intentionally preserves the base pinned-drop behavior where #[pin_v2] types must use pin_drop, while non-#[pin_v2] types may still implement pin_drop.

r? @petrochenkov

Moved the syntactic fn drop(&pin mut self) predicate onto ast::Fn as is_pin_drop_sugar, so it is shared by resolver and AST lowering.
Updated rustc_resolve to call the shared ast::Fn helper instead of keeping a resolver-local predicate.
Moved the common get_partial_res(i.id) / trait-item def-id lookup into resolve_pin_drop_sugar_impl_item.
Simplified resolve_pin_drop_sugar_impl_item so it always returns (Ident, Result<DefId, ErrorGuaranteed>); the def-id lookup and effective-ident choice are now separated.
Kept the existing behavior: syntactic resolver rewrite to effective pin_drop, later validation against real Drop::pin_drop, targeted custom-trait diagnostic, and normal E0407 behavior.

@rustbot ready

P8L1 · 2026-05-14T14:49:18Z

Thanks for the review, I addressed your concerns

@rustbot ready

petrochenkov · 2026-05-14T15:50:09Z

@bors r+

rust-bors · 2026-05-14T15:50:12Z

📌 Commit 282ec28 has been approved by petrochenkov

It is now in the queue for this repository.

@petrochenkov

…ream, r=petrochenkov Implement pinned drop sugar Implements `fn drop(&pin mut self)` as sugar for `Drop::pin_drop`. The resolver recognizes `fn drop(&pin mut self)` syntactically in trait impls and performs lookup using the effective `pin_drop` name. AST lowering independently rechecks the syntactic sugar, validates that the resolved item belongs to the actual `Drop` lang trait, and emits HIR with ident `pin_drop` for accepted sugar. Existing type checking, Drop validation, drop glue, and direct-call checks remain unchanged. Drop identity is checked during AST lowering through `tcx.lang_items().drop_trait()`, after resolver has performed the effective `pin_drop` lookup. The resolver does not need to know whether the trait is the actual `Drop` lang item, and it no longer passes marked impl item IDs to lowering. This intentionally preserves the base pinned-drop behavior where `#[pin_v2]` types must use `pin_drop`, while non-`#[pin_v2]` types may still implement `pin_drop`. r? @petrochenkov ## Related rust-lang#144537 rust-lang#130494

…uwer Rollup of 4 pull requests Successful merges: - #156452 (Implement pinned drop sugar) - #156571 (Disable `main_needs_argc_argv` for Wasm) - #156565 (delegation: emit error when self type is not specified and accessed) - #156570 (tests: extend remap-path-prefix-std to all stdlib rlibs)

@petrochenkov

…rochenkov Implement pinned drop sugar Implements `fn drop(&pin mut self)` as sugar for `Drop::pin_drop`. The resolver recognizes `fn drop(&pin mut self)` syntactically in trait impls and performs lookup using the effective `pin_drop` name. AST lowering independently rechecks the syntactic sugar, validates that the resolved item belongs to the actual `Drop` lang trait, and emits HIR with ident `pin_drop` for accepted sugar. Existing type checking, Drop validation, drop glue, and direct-call checks remain unchanged. Drop identity is checked during AST lowering through `tcx.lang_items().drop_trait()`, after resolver has performed the effective `pin_drop` lookup. The resolver does not need to know whether the trait is the actual `Drop` lang item, and it no longer passes marked impl item IDs to lowering. This intentionally preserves the base pinned-drop behavior where `#[pin_v2]` types must use `pin_drop`, while non-`#[pin_v2]` types may still implement `pin_drop`. r? @petrochenkov ## Related #144537 #130494

rust-bors · 2026-05-15T04:14:28Z

💔 Test for 5af63f6 failed: CI. Failed job:

auto - i686-msvc-1 (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-05-15T04:14:31Z

The job i686-msvc-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

P8L1 · 2026-05-15T10:45:48Z

@petrochenkov

CI seems to have failed due to transient infra rather than this PR:

'The hosted runner lost communication with the server. Anything in your workflow that terminates the runner process, starves it for CPU/Memory, or blocks its network access can cause this error.'

Can we please retry the failed CI run?

petrochenkov · 2026-05-15T12:01:46Z

@bors retry

@petrochenkov

…ream, r=petrochenkov Implement pinned drop sugar Implements `fn drop(&pin mut self)` as sugar for `Drop::pin_drop`. The resolver recognizes `fn drop(&pin mut self)` syntactically in trait impls and performs lookup using the effective `pin_drop` name. AST lowering independently rechecks the syntactic sugar, validates that the resolved item belongs to the actual `Drop` lang trait, and emits HIR with ident `pin_drop` for accepted sugar. Existing type checking, Drop validation, drop glue, and direct-call checks remain unchanged. Drop identity is checked during AST lowering through `tcx.lang_items().drop_trait()`, after resolver has performed the effective `pin_drop` lookup. The resolver does not need to know whether the trait is the actual `Drop` lang item, and it no longer passes marked impl item IDs to lowering. This intentionally preserves the base pinned-drop behavior where `#[pin_v2]` types must use `pin_drop`, while non-`#[pin_v2]` types may still implement `pin_drop`. r? @petrochenkov ## Related rust-lang#144537 rust-lang#130494

…uwer Rollup of 8 pull requests Successful merges: - #156493 (actually run the temp_dir doctest) - #156452 (Implement pinned drop sugar) - #156600 (Make const param default test reproduce original ICE) - #156556 (Require UTF-8 in `Utf8Pattern::StringPattern`) - #156565 (delegation: emit error when self type is not specified and accessed) - #156577 (Test EII UI tests with prefer-dynamic) - #156586 (Use DropCtxt::new_block and new_block_with_statements systematically.) - #156587 (Correctly handle associated items in rustdoc macro expansion)

@petrochenkov

…ream, r=petrochenkov Implement pinned drop sugar Implements `fn drop(&pin mut self)` as sugar for `Drop::pin_drop`. The resolver recognizes `fn drop(&pin mut self)` syntactically in trait impls and performs lookup using the effective `pin_drop` name. AST lowering independently rechecks the syntactic sugar, validates that the resolved item belongs to the actual `Drop` lang trait, and emits HIR with ident `pin_drop` for accepted sugar. Existing type checking, Drop validation, drop glue, and direct-call checks remain unchanged. Drop identity is checked during AST lowering through `tcx.lang_items().drop_trait()`, after resolver has performed the effective `pin_drop` lookup. The resolver does not need to know whether the trait is the actual `Drop` lang item, and it no longer passes marked impl item IDs to lowering. This intentionally preserves the base pinned-drop behavior where `#[pin_v2]` types must use `pin_drop`, while non-`#[pin_v2]` types may still implement `pin_drop`. r? @petrochenkov ## Related rust-lang#144537 rust-lang#130494

Rollup of 11 pull requests Successful merges: - #148788 (Unconstrained parameter fix) - #153238 (debuginfo: slices are DW_TAG_array_type's) - #155521 (Add lint againts invalid runtime symbol definitions) - #156319 (Require EIIs to be defined when we compile a rust dylib) - #156452 (Implement pinned drop sugar) - #156600 (Make const param default test reproduce original ICE) - #156493 (actually run the temp_dir doctest) - #156556 (Require UTF-8 in `Utf8Pattern::StringPattern`) - #156565 (delegation: emit error when self type is not specified and accessed) - #156586 (Use DropCtxt::new_block and new_block_with_statements systematically.) - #156587 (Correctly handle associated items in rustdoc macro expansion)

rustbot assigned petrochenkov May 11, 2026

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P8L1 force-pushed the implement-pin-drop-sugar-upstream branch from 9c61b5e to 9913270 Compare May 13, 2026 11:43

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Implement pinned drop sugar

282ec28

P8L1 force-pushed the implement-pin-drop-sugar-upstream branch from 51db9cb to 282ec28 Compare May 14, 2026 14:55

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JonathanBrouwer mentioned this pull request May 14, 2026

Rollup of 4 pull requests #156584

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Rollup of 8 pull requests #156605

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Zalathar mentioned this pull request May 15, 2026

Rollup of 11 pull requests #156610

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