Improve type mismatch annotation for lets with block-wrapped initializers by chenyukang · Pull Request #161730 · rust-lang/rust

chenyukang · 2026-08-25T08:45:11Z

rustbot · 2026-08-25T08:45:17Z

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folkertdev · 2026-08-26T13:39:50Z

+                parent => Some(parent),
+            },
+        ) else {
+            return;


why is this early return correct? Maybe add a comment?

i think it's better to change it to expect here, an expression must have a non-block ancestor.

folkertdev · 2026-08-26T13:40:24Z

-        match (self.tcx.parent_hir_node(expr.hir_id), error) {
+        // Skip nested block find the correct parent node to point at
+        let mut current_hir_id = expr.hir_id;
+        let Some(parent) = self.tcx.hir_parent_iter(expr.hir_id).find_map(


I played around with a labeled block here instead but it's not obviously better.

folkertdev · 2026-08-26T16:30:37Z

CI got stuck somehow. Maybe just rebase on current main and try again?

…zers

rustbot · 2026-08-27T00:46:21Z

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.

folkertdev · 2026-08-27T10:26:05Z

@bors r+ rollup

rust-bors · 2026-08-27T10:26:07Z

📌 Commit ef175bb has been approved by folkertdev

It is now in the queue for this repository.

…-type-mismatch-attribution, r=folkertdev Improve type mismatch annotation for lets with block-wrapped initializers Fixes rust-lang#127048

Rollup of 7 pull requests Successful merges: - #150075 (Implement clamp_to) - #157145 (Codegen Overloaded LLVM intrinsics based on their name) - #161866 (delegation: add tests fixating behavior of delegating to default trait implementations) - #161456 (reduce perf impact of scalar size checks) - #161730 (Improve type mismatch annotation for lets with block-wrapped initializers) - #161828 (Never type after-stabilization cleanup) - #161860 (atomicptr.rs test: remove unused import)

…-type-mismatch-attribution, r=folkertdev Improve type mismatch annotation for lets with block-wrapped initializers Fixes rust-lang#127048

Rollup of 14 pull requests Successful merges: - #150075 (Implement clamp_to) - #159103 (fix(reborrow): recursive implementation) - #160848 (std: avoid aliasing violations when wrapping opaque C types) - #161421 (Include startup crt objects on WASI for more outputs) - #161805 (Prefer ambiguous candidates when deduplicating traits in scope, so `ambiguous_glob_imported_traits` doesn't depend on import order) - #161862 (Put data segment in specified section with link_section on wasm) - #161866 (delegation: add tests fixating behavior of delegating to default trait implementations) - #161456 (reduce perf impact of scalar size checks) - #161666 (Print vendor instructions in `x vendor`) - #161730 (Improve type mismatch annotation for lets with block-wrapped initializers) - #161828 (Never type after-stabilization cleanup) - #161860 (atomicptr.rs test: remove unused import) - #161870 (bind to [::1] instead of 127.0.0.1 in documentation examples for v6 UDP methods) - #161876 (rustdoc: Correctly handle when a macro generates multiple items in `--generate-macro-expansion`)

…-type-mismatch-attribution, r=folkertdev Improve type mismatch annotation for lets with block-wrapped initializers Fixes rust-lang#127048

…uwer Rollup of 21 pull requests Successful merges: - #158609 (Update sccache to 0.16.0) - #150075 (Implement clamp_to) - #159103 (fix(reborrow): recursive implementation) - #160562 (add target feature ABI checks for SPARC) - #160848 (std: avoid aliasing violations when wrapping opaque C types) - #161421 (Include startup crt objects on WASI for more outputs) - #161805 (Prefer ambiguous candidates when deduplicating traits in scope, so `ambiguous_glob_imported_traits` doesn't depend on import order) - #161862 (Put data segment in specified section with link_section on wasm) - #161866 (delegation: add tests fixating behavior of delegating to default trait implementations) - #161456 (reduce perf impact of scalar size checks) - #161528 (Add regression test to ensure optimal compilation) - #161666 (Print vendor instructions in `x vendor`) - #161730 (Improve type mismatch annotation for lets with block-wrapped initializers) - #161828 (Never type after-stabilization cleanup) - #161859 (Do not optimize MIR for comptime ConstFns) - #161860 (atomicptr.rs test: remove unused import) - #161870 (bind to [::1] instead of 127.0.0.1 in documentation examples for v6 UDP methods) - #161876 (rustdoc: Correctly handle when a macro generates multiple items in `--generate-macro-expansion`) - #161889 (Add link to ownership section in ptr::read docs) - #161890 (rustdoc: some clarifying comments) - #161891 (Mark `extern_item_impls` feature as incomplete) Failed merges: - #161702 (Use `drop_guard` in some places in {core,alloc,std})

…uwer Rollup of 21 pull requests Successful merges: - #150075 (Implement clamp_to) - #159103 (fix(reborrow): recursive implementation) - #160562 (add target feature ABI checks for SPARC) - #160848 (std: avoid aliasing violations when wrapping opaque C types) - #161421 (Include startup crt objects on WASI for more outputs) - #161805 (Prefer ambiguous candidates when deduplicating traits in scope, so `ambiguous_glob_imported_traits` doesn't depend on import order) - #161862 (Put data segment in specified section with link_section on wasm) - #161866 (delegation: add tests fixating behavior of delegating to default trait implementations) - #157218 (Track items behind `cfg_select` in the same way we do for `cfg`) - #161456 (reduce perf impact of scalar size checks) - #161528 (Add regression test to ensure optimal compilation) - #161666 (Print vendor instructions in `x vendor`) - #161730 (Improve type mismatch annotation for lets with block-wrapped initializers) - #161828 (Never type after-stabilization cleanup) - #161859 (Do not optimize MIR for comptime ConstFns) - #161860 (atomicptr.rs test: remove unused import) - #161870 (bind to [::1] instead of 127.0.0.1 in documentation examples for v6 UDP methods) - #161876 (rustdoc: Correctly handle when a macro generates multiple items in `--generate-macro-expansion`) - #161889 (Add link to ownership section in ptr::read docs) - #161890 (rustdoc: some clarifying comments) - #161891 (Mark `extern_item_impls` feature as incomplete) Failed merges: - #161702 (Use `drop_guard` in some places in {core,alloc,std})

Rollup merge of #161730 - chenyukang:yukang-fix-127048-local-type-mismatch-attribution, r=folkertdev Improve type mismatch annotation for lets with block-wrapped initializers Fixes #127048

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 Aug 25, 2026

rustbot assigned folkertdev Aug 25, 2026

folkertdev reviewed Aug 26, 2026

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 26, 2026

chenyukang force-pushed the yukang-fix-127048-local-type-mismatch-attribution branch 2 times, most recently from ca30e20 to a83939a Compare August 26, 2026 15:25

chenyukang added 2 commits August 27, 2026 08:45

Add regression test for nested initializer mismatch attribution

17db56c

Improve type mismatch annotation for lets with block-wrapped initiali…

ef175bb

…zers

chenyukang force-pushed the yukang-fix-127048-local-type-mismatch-attribution branch from a83939a to ef175bb Compare August 27, 2026 00:46

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 27, 2026

matthiaskrgr mentioned this pull request Aug 27, 2026

Rollup of 4 pull requests #161863

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matthiaskrgr mentioned this pull request Aug 27, 2026

Rollup of 5 pull requests #161869

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matthiaskrgr mentioned this pull request Aug 27, 2026

Rollup of 7 pull requests #161871

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matthiaskrgr mentioned this pull request Aug 27, 2026

Rollup of 12 pull requests #161874

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JonathanBrouwer mentioned this pull request Aug 27, 2026

Rollup of 11 pull requests #161875

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JonathanBrouwer mentioned this pull request Aug 27, 2026

Rollup of 11 pull requests #161878

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GuillaumeGomez mentioned this pull request Aug 27, 2026

Rollup of 14 pull requests #161884

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JonathanBrouwer mentioned this pull request Aug 28, 2026

Rollup of 18 pull requests #161901

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JonathanBrouwer mentioned this pull request Aug 28, 2026

Rollup of 21 pull requests #161905

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JonathanBrouwer mentioned this pull request Aug 28, 2026

Rollup of 21 pull requests #161906

Merged

rust-bors Bot merged commit 8d6bd02 into rust-lang:main Aug 28, 2026
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rustbot added this to the 1.100.0 milestone Aug 28, 2026

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Improve type mismatch annotation for lets with block-wrapped initializers - #161730

Improve type mismatch annotation for lets with block-wrapped initializers#161730
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chenyukang:yukang-fix-127048-local-type-mismatch-attribution

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