do not suggest precise capturing when the opaque span is in a macro expansion by Albab-Hasan · Pull Request #163581 · rust-lang/rust

Albab-Hasan · 2026-10-01T04:21:47Z

impl_trait_overcapture_suggestion anchored every suggestion on tcx.def_span(opaque_def_id) with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the MachineApplicable suggestion produces:

error: expected item after attributes

the obvious patch of calling can_be_used_for_suggestions() directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps DesugaringKind::OpaqueTy onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making from_expansion() unconditionally true (SyntaxContext::in_external_macro already lists this kind for the same reason). the fix calls parent_callsite() to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span.

notes. a function written inside a macro_rules! body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no .fixed file: run-rustfix requires exit 0 but this change removes a suggestion rather than correcting one.

no existing baseline was re-blessed.

fixes #139567

r? @oli-obk

oli-obk · 2026-10-01T05:47:32Z

pull this to the start of this function and reuse it in both sites

View changes since the review

the test records what the compiler emits today: impl_trait_overcapture_suggestion anchors its suggestion on the opaque def span, which for an opaque inside an attribute macro expansion is the attribute itself, not a type position. the suggestion is machine-applicable, so edition migration applies it and produces error: expected item after attributes

…ro expansion impl_trait_overcapture_suggestion anchored every suggestion on tcx.def_span(opaque_def_id) with no expansion check. for an opaque created inside an attribute macro expansion that span is the attribute, which is not a type position, so applying the machine-applicable suggestion breaks the file the obvious patch of calling can_be_used_for_suggestions() on that span directly suppresses all suggestions including for ordinary code, because ast lowering stamps DesugaringKind::OpaqueTy onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making from_expansion() unconditionally true. the fix calls parent_callsite() to peel that single desugaring layer and asks can_be_used_for_suggestions() about the span underneath the guard sits at function entry rather than beside the rpit_span push because the apit rename and the generics-list insertion are anchored on the same span, so one check covers all three fixes rust-lang#139567

rustbot · 2026-10-01T06:19:15Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

oli-obk

@bors r+ rollup

View changes since this review

rust-bors · 2026-10-01T07:02:39Z

📌 Commit 057e810 has been tentatively approved by oli-obk

It will be put into the queue for this repository once PR CI succeeds.

@oli-obk

…n-in-macro, r=oli-obk do not suggest precise capturing when the opaque span is in a macro expansion `impl_trait_overcapture_suggestion` anchored every suggestion on `tcx.def_span(opaque_def_id)` with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the `MachineApplicable` suggestion produces: ``` error: expected item after attributes ``` the obvious patch of calling `can_be_used_for_suggestions()` directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps `DesugaringKind::OpaqueTy` onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making `from_expansion()` unconditionally true (`SyntaxContext::in_external_macro` already lists this kind for the same reason). the fix calls `parent_callsite()` to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span. notes. a function written inside a `macro_rules!` body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no `.fixed` file: `run-rustfix` requires exit 0 but this change removes a suggestion rather than correcting one. no existing baseline was re-blessed. fixes rust-lang#139567 r? @oli-obk

…uwer Rollup of 9 pull requests Successful merges: - #163483 (Bump bootstrap compiler to 1.100.0 beta) - #161380 (only rerun const eval in next-solver if the const actually references opaques) - #162900 (Some refactorings around metadata encoding) - #163580 (Provide better doc code example for `UnixDatagram::bind_addr` and `UnixListener::bind_addr`) - #163584 ([triagebot] Ping me for debugger visualizer changes) - #162782 (Fix rustdoc ICE caused by mishandling of ambiguity errors) - #163314 (move `#[macro_export]` on declarative macro check to `rustc_attr_parsing`) - #163405 (Remove some #[linkage] options) - #163581 (do not suggest precise capturing when the opaque span is in a macro expansion)

@oli-obk

…n-in-macro, r=oli-obk do not suggest precise capturing when the opaque span is in a macro expansion `impl_trait_overcapture_suggestion` anchored every suggestion on `tcx.def_span(opaque_def_id)` with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the `MachineApplicable` suggestion produces: ``` error: expected item after attributes ``` the obvious patch of calling `can_be_used_for_suggestions()` directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps `DesugaringKind::OpaqueTy` onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making `from_expansion()` unconditionally true (`SyntaxContext::in_external_macro` already lists this kind for the same reason). the fix calls `parent_callsite()` to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span. notes. a function written inside a `macro_rules!` body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no `.fixed` file: `run-rustfix` requires exit 0 but this change removes a suggestion rather than correcting one. no existing baseline was re-blessed. fixes rust-lang#139567 r? @oli-obk

@oli-obk

…n-in-macro, r=oli-obk do not suggest precise capturing when the opaque span is in a macro expansion `impl_trait_overcapture_suggestion` anchored every suggestion on `tcx.def_span(opaque_def_id)` with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the `MachineApplicable` suggestion produces: ``` error: expected item after attributes ``` the obvious patch of calling `can_be_used_for_suggestions()` directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps `DesugaringKind::OpaqueTy` onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making `from_expansion()` unconditionally true (`SyntaxContext::in_external_macro` already lists this kind for the same reason). the fix calls `parent_callsite()` to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span. notes. a function written inside a `macro_rules!` body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no `.fixed` file: `run-rustfix` requires exit 0 but this change removes a suggestion rather than correcting one. no existing baseline was re-blessed. fixes rust-lang#139567 r? @oli-obk

@oli-obk

…n-in-macro, r=oli-obk do not suggest precise capturing when the opaque span is in a macro expansion `impl_trait_overcapture_suggestion` anchored every suggestion on `tcx.def_span(opaque_def_id)` with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the `MachineApplicable` suggestion produces: ``` error: expected item after attributes ``` the obvious patch of calling `can_be_used_for_suggestions()` directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps `DesugaringKind::OpaqueTy` onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making `from_expansion()` unconditionally true (`SyntaxContext::in_external_macro` already lists this kind for the same reason). the fix calls `parent_callsite()` to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span. notes. a function written inside a `macro_rules!` body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no `.fixed` file: `run-rustfix` requires exit 0 but this change removes a suggestion rather than correcting one. no existing baseline was re-blessed. fixes rust-lang#139567 r? @oli-obk

Albab-Hasan · 2026-10-01T12:06:16Z

thanks!

Rollup of 11 pull requests Successful merges: - #163483 (Bump bootstrap compiler to 1.100.0 beta) - #161380 (only rerun const eval in next-solver if the const actually references opaques) - #162900 (Some refactorings around metadata encoding) - #163580 (Provide better doc code example for `UnixDatagram::bind_addr` and `UnixListener::bind_addr`) - #163584 ([triagebot] Ping me for debugger visualizer changes) - #162904 (Fix ICE for ambiguous candidates on method probing) - #163281 (Add `f16` inline ASM support to `spirv.rs`) - #163314 (move `#[macro_export]` on declarative macro check to `rustc_attr_parsing`) - #163405 (Remove some #[linkage] options) - #163530 (`const impl PartialEq` for `f16b`) - #163581 (do not suggest precise capturing when the opaque span is in a macro expansion)

…uwer Rollup of 20 pull requests Successful merges: - #163483 (Bump bootstrap compiler to 1.100.0 beta) - #161380 (only rerun const eval in next-solver if the const actually references opaques) - #162900 (Some refactorings around metadata encoding) - #163461 (Improve diagnostic deduplication) - #163580 (Provide better doc code example for `UnixDatagram::bind_addr` and `UnixListener::bind_addr`) - #163584 ([triagebot] Ping me for debugger visualizer changes) - #159021 (windows-gnu: enable native TLS) - #161467 (wfcheck: name the item that discards an unused type parameter) - #162618 (trait_selection: Preserve eager normalization failures) - #162904 (Fix ICE for ambiguous candidates on method probing) - #163064 (Avoid computing overflowed goal chains for crate dependencies) - #163281 (Add `f16` inline ASM support to `spirv.rs`) - #163314 (move `#[macro_export]` on declarative macro check to `rustc_attr_parsing`) - #163360 ([rustdoc] Correctly handle rustc_allow_incoherent_impl on primitive methods) - #163385 (GVN transmutes of Immediate::Uninit to Immediate::Uninit) - #163405 (Remove some #[linkage] options) - #163530 (`const impl PartialEq` for `f16b`) - #163581 (do not suggest precise capturing when the opaque span is in a macro expansion) - #163590 (Make `AllocatorNightly` less clever) - #163599 (Add union pattern reference change to relnotes)

@oli-obk

Rollup merge of #163581 - Albab-Hasan:no-use-bound-suggestion-in-macro, r=oli-obk do not suggest precise capturing when the opaque span is in a macro expansion `impl_trait_overcapture_suggestion` anchored every suggestion on `tcx.def_span(opaque_def_id)` with no expansion check. for an opaque inside an attribute macro expansion that span is the attribute itself, so applying the `MachineApplicable` suggestion produces: ``` error: expected item after attributes ``` the obvious patch of calling `can_be_used_for_suggestions()` directly on that span suppresses all suggestions including for ordinary code, because AST lowering stamps `DesugaringKind::OpaqueTy` onto the opaque span at compiler/rustc_ast_lowering/src/lib.rs:1825, making `from_expansion()` unconditionally true (`SyntaxContext::in_external_macro` already lists this kind for the same reason). the fix calls `parent_callsite()` to peel that layer first. the guard sits at function entry because the APIT rename and generics-list insertion share the same span. notes. a function written inside a `macro_rules!` body also loses its suggestion under this guard even though the edit would be valid in the macro definition; a token passed as an argument keeps its suggestion because it retains the callers syntax context. and there is no `.fixed` file: `run-rustfix` requires exit 0 but this change removes a suggestion rather than correcting one. no existing baseline was re-blessed. fixes #139567 r? @oli-obk

…uwer Rollup of 20 pull requests Successful merges: - rust-lang/rust#163483 (Bump bootstrap compiler to 1.100.0 beta) - rust-lang/rust#161380 (only rerun const eval in next-solver if the const actually references opaques) - rust-lang/rust#162900 (Some refactorings around metadata encoding) - rust-lang/rust#163461 (Improve diagnostic deduplication) - rust-lang/rust#163580 (Provide better doc code example for `UnixDatagram::bind_addr` and `UnixListener::bind_addr`) - rust-lang/rust#163584 ([triagebot] Ping me for debugger visualizer changes) - rust-lang/rust#159021 (windows-gnu: enable native TLS) - rust-lang/rust#161467 (wfcheck: name the item that discards an unused type parameter) - rust-lang/rust#162618 (trait_selection: Preserve eager normalization failures) - rust-lang/rust#162904 (Fix ICE for ambiguous candidates on method probing) - rust-lang/rust#163064 (Avoid computing overflowed goal chains for crate dependencies) - rust-lang/rust#163281 (Add `f16` inline ASM support to `spirv.rs`) - rust-lang/rust#163314 (move `#[macro_export]` on declarative macro check to `rustc_attr_parsing`) - rust-lang/rust#163360 ([rustdoc] Correctly handle rustc_allow_incoherent_impl on primitive methods) - rust-lang/rust#163385 (GVN transmutes of Immediate::Uninit to Immediate::Uninit) - rust-lang/rust#163405 (Remove some #[linkage] options) - rust-lang/rust#163530 (`const impl PartialEq` for `f16b`) - rust-lang/rust#163581 (do not suggest precise capturing when the opaque span is in a macro expansion) - rust-lang/rust#163590 (Make `AllocatorNightly` less clever) - rust-lang/rust#163599 (Add union pattern reference change to relnotes)

rustbot assigned oli-obk Oct 1, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Oct 1, 2026

Albab-Hasan changed the title ~~No use bound suggestion in macro~~ do not suggest precise capturing when the opaque span is in a macro expansion Oct 1, 2026

oli-obk reviewed Oct 1, 2026

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Albab-Hasan added 2 commits October 1, 2026 12:07

Albab-Hasan force-pushed the no-use-bound-suggestion-in-macro branch from fc8a360 to 057e810 Compare October 1, 2026 06:19

Albab-Hasan requested a review from oli-obk October 1, 2026 06:22

oli-obk approved these changes Oct 1, 2026

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rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 1, 2026

JonathanBrouwer mentioned this pull request Oct 1, 2026

Rollup of 9 pull requests #163595

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Rollup of 9 pull requests #163596

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Rollup of 10 pull requests #163600

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Rollup of 11 pull requests #163601

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JonathanBrouwer mentioned this pull request Oct 1, 2026

Rollup of 20 pull requests #163609

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rust-bors Bot merged commit 2dfd15d into rust-lang:main Oct 2, 2026
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rustbot added this to the 1.101.0 milestone Oct 2, 2026

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do not suggest precise capturing when the opaque span is in a macro expansion - #163581

do not suggest precise capturing when the opaque span is in a macro expansion#163581
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