Silence redundant failed obligations on the same statement by estebank · Pull Request #163913 · rust-lang/rust

estebank · 2026-10-07T02:39:58Z

On multiple unment obligations in the same method chain, only emit one. On unmet Sized obligations on a binding, its type and its init expression, only emit one.

rustbot · 2026-10-07T02:40:02Z

changes to the core type system

cc @lcnr

rustbot · 2026-10-07T02:40:05Z

r? @oli-obk

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estebank · 2026-10-07T05:25:46Z

Easier to review per-comit: first add mild mechanic changes to have more tracking to be used later, added the tests that I wanted to tackle, and finally the actual logic change that affects the emitted errors.

oli-obk · 2026-10-07T11:16:07Z

                                field_ty,
                                expr.span,
-                                ObligationCauseCode::Misc,
+                                ObligationCauseCode::WellFormed(WellFormedLoc::None),


may be worth figuring out a WellFormedLoc for, as this is the only use of None that won't be removed when the old solver gets nuked Soon ™️

View changes since the review

Using the HirId of the expr doesn't change anything today (because it is the offset_of! macro which already points at the whole expr), but might in the future. Changed in the last commit.

rustbot · 2026-10-07T11:23:00Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

oli-obk · 2026-10-08T10:26:39Z

@bors r+

rust-bors · 2026-10-08T10:26:57Z

📌 Commit 9d0888f has been approved by oli-obk

It is now in the queue for this repository.

Silence redundant failed obligations on the same statement Fix rust-lang#84346, fix rust-lang#105753. On multiple unment obligations in the same method chain, only emit one. On unmet `Sized` obligations on a binding, its type and its init expression, only emit one.

JonathanBrouwer · 2026-10-08T12:41:19Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #163984 (comment)

rust-bors · 2026-10-08T12:41:27Z

This pull request was unapproved.

This PR was contained in a rollup (#163984), which was unapproved.

View changes since this unapproval

Carry more information for well-formed obligations coming from expressions.

fix fmt

Reduces the number of errors being emitted by a single unmet `Sized` (or other) bound in method call chains.

…code

rustbot · 2026-10-08T16:10:24Z

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.

estebank · 2026-10-08T17:54:33Z

@bors r=oli-obk

rust-bors · 2026-10-08T17:54:37Z

📌 Commit 83bd0e0 has been approved by oli-obk

It is now in the queue for this repository.

…uwer Rollup of 19 pull requests Successful merges: - #156112 (Distinguish `repr(C)` ZSTs from others in ABI computation) - #157941 (Deny partial `-Z stack-protector` by default in all editions) - #163462 (Fix COFF renaming of decorated (stdcall/fastcall/vectorcall) exports) - #163855 (Include enclosing item's context on const errors) - #163861 (Run LLDB debuginfo tests on `x86_64-mingw`) - #163913 ( Silence redundant failed obligations on the same statement) - #161201 (Speed up tidy again) - #163380 (Tweak "name not found" resolution error when it happens from within a derive expansion) - #163538 (Add `rustc::missing_generic_type_visitable` lint) - #163617 (mips: make `Complex<T>` ABI match GCC) - #163772 (comptime fn error: suggest wrapping in const block) - #163813 (use pre-borrowck typing env for early MIR validation) - #163924 (replace instances of NonNull::new(&mut x).expect("...") with NonNull::from_mut) - #163958 (only make `RustaceansAreAwesome` satisfy trait clauses) - #163960 (vexos: clear .bss from assembly) - #163974 (Condense AdtDef lang item checks into one match) - #163979 (Add `bf16` to arm features) - #163989 (Revert "compiletest: stream output of executor process when --no-capture is set") - #163995 (m68k-unknown-none-elf: Remove code model) Failed merges: - #163832 (reject non-async coroutine closures as async callables) - #163972 (const-eval: ICE when we hit a non-const fn)

Rollup merge of #163913 - estebank:wellformedloc, r=oli-obk Silence redundant failed obligations on the same statement Fix #84346, fix #105753. On multiple unment obligations in the same method chain, only emit one. On unmet `Sized` obligations on a binding, its type and its init expression, only emit one.

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. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Oct 7, 2026

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estebank force-pushed the wellformedloc branch from 5aa46fd to 1151b3e Compare October 7, 2026 05:24

oli-obk changed the title ~~Silence redudant failed obligations on the same statement~~ Silence redundant failed obligations on the same statement Oct 7, 2026

oli-obk requested changes Oct 7, 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 Oct 7, 2026

estebank force-pushed the wellformedloc branch from 1151b3e to 55d1925 Compare October 7, 2026 15:17

estebank added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Oct 7, 2026

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 8, 2026

oli-obk approved these changes Oct 8, 2026

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JonathanBrouwer mentioned this pull request Oct 8, 2026

Rollup of 8 pull requests #163984

Closed

rust-bors Bot 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Oct 8, 2026

estebank added 2 commits October 8, 2026 16:05

Tweak WellFormedLoc

afe9fa8

Carry more information for well-formed obligations coming from expressions.

Add tests for 84346 and 105753

6360772

fix fmt

estebank added 3 commits October 8, 2026 16:05

Silence redundant failed obligations on the same statement

7328f11

Reduces the number of errors being emitted by a single unmet `Sized` (or other) bound in method call chains.

Use WellFormedLoc::HirId for offset_of! Sized obligation cause …

98cd354

…code

Update test output

83bd0e0

estebank force-pushed the wellformedloc branch from 9d0888f to 83bd0e0 Compare October 8, 2026 16:10

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 Oct 8, 2026

JonathanBrouwer mentioned this pull request Oct 8, 2026

Rollup of 19 pull requests #164005

Merged

rust-bors Bot merged commit 41dce4c into rust-lang:main Oct 8, 2026
14 checks passed

rustbot added this to the 1.101.0 milestone Oct 8, 2026

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