More robustly deal with relaxed bounds and improve their diagnostics by fmease · Pull Request #142693 · rust-lang/rust

fmease · 2025-06-18T20:23:53Z

Scaffolding for #135229 (CC #135331)

Fixes #136944 (6th commit).
Fixes #142718 (8th commit).

fmease · 2025-06-20T21:20:38Z

@bors2 try @rust-timer queue

rust-bors · 2025-06-20T21:20:42Z

⌛ Trying commit 04dad4e with merge bfa10de…

To cancel the try build, run the command @bors2 try cancel.

More robustly deal with relaxed bounds and improve their diagnostics Scaffolding for #135229 (CC #135331) Fixes #136944. Fixes #142718.

rust-bors · 2025-06-20T23:49:40Z

☀️ Try build successful (CI)
Build commit: bfa10de (bfa10de6407128926b18c60d51c9f19df73e336c, parent: 9c4ff566babe632af5e30281a822d1ae9972873b)

rust-timer · 2025-06-21T02:22:46Z

Finished benchmarking commit (bfa10de): comparison URL.

Overall result: ❌ regressions - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	3.0%	[3.0%, 3.0%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.0%	[3.0%, 3.0%]	1

Max RSS (memory usage)

Results (secondary -2.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.5%	[-5.8%, -1.8%]	6
All ❌✅ (primary)	-	-	0

Cycles

Results (primary 2.9%, secondary 4.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.9%	[2.9%, 2.9%]	1
Regressions ❌ (secondary)	4.4%	[2.8%, 7.6%]	10
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.9%	[2.9%, 2.9%]	1

Binary size

Results (primary 1.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.1%	[1.1%, 1.1%]	1

Bootstrap: 692.606s -> 692.191s (-0.06%)
Artifact size: 372.01 MiB -> 371.99 MiB (-0.01%)

bors · 2025-06-27T20:17:23Z

☔ The latest upstream changes (presumably #143091) made this pull request unmergeable. Please resolve the merge conflicts.

fmease · 2025-06-27T22:56:30Z

#142693 (comment)

Looks spurious?

fmease · 2025-07-18T10:32:02Z

@bors rollup- alleviate pressure

…er-errors More robustly deal with relaxed bounds and improve their diagnostics Scaffolding for rust-lang#135229 (CC rust-lang#135331) Fixes rust-lang#136944 (6th commit). Fixes rust-lang#142718 (8th commit).

Rollup of 9 pull requests Successful merges: - #138554 (Distinguish delim kind to decide whether to emit unexpected closing delimiter) - #142673 (Show the offset, length and memory of uninit read errors) - #142693 (More robustly deal with relaxed bounds and improve their diagnostics) - #143382 (stabilize `const_slice_reverse`) - #143928 (opt-dist: make llvm builds optional) - #143961 (Correct which exploit mitigations are enabled by default) - #144050 (Fix encoding of link_section and no_mangle cross crate) - #144059 (Refactor `CrateLoader` into the `CStore`) - #144123 (Generalize `unsize` and `unsize_into` destinations) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #142693 - fmease:unbound-bettering, r=compiler-errors More robustly deal with relaxed bounds and improve their diagnostics Scaffolding for #135229 (CC #135331) Fixes #136944 (6th commit). Fixes #142718 (8th commit).

Rollup of 9 pull requests Successful merges: - rust-lang/rust#138554 (Distinguish delim kind to decide whether to emit unexpected closing delimiter) - rust-lang/rust#142673 (Show the offset, length and memory of uninit read errors) - rust-lang/rust#142693 (More robustly deal with relaxed bounds and improve their diagnostics) - rust-lang/rust#143382 (stabilize `const_slice_reverse`) - rust-lang/rust#143928 (opt-dist: make llvm builds optional) - rust-lang/rust#143961 (Correct which exploit mitigations are enabled by default) - rust-lang/rust#144050 (Fix encoding of link_section and no_mangle cross crate) - rust-lang/rust#144059 (Refactor `CrateLoader` into the `CStore`) - rust-lang/rust#144123 (Generalize `unsize` and `unsize_into` destinations) r? `@ghost` `@rustbot` modify labels: rollup

…er-errors More robustly deal with relaxed bounds and improve their diagnostics Scaffolding for rust-lang#135229 (CC rust-lang#135331) Fixes rust-lang#136944 (6th commit). Fixes rust-lang#142718 (8th commit).

…iaskrgr Rollup of 9 pull requests Successful merges: - rust-lang#138554 (Distinguish delim kind to decide whether to emit unexpected closing delimiter) - rust-lang#142673 (Show the offset, length and memory of uninit read errors) - rust-lang#142693 (More robustly deal with relaxed bounds and improve their diagnostics) - rust-lang#143382 (stabilize `const_slice_reverse`) - rust-lang#143928 (opt-dist: make llvm builds optional) - rust-lang#143961 (Correct which exploit mitigations are enabled by default) - rust-lang#144050 (Fix encoding of link_section and no_mangle cross crate) - rust-lang#144059 (Refactor `CrateLoader` into the `CStore`) - rust-lang#144123 (Generalize `unsize` and `unsize_into` destinations) r? `@ghost` `@rustbot` modify labels: rollup

Further tighten up relaxed bounds Follow-up to #142693, #135331 and #135841. Fixes #143122. * Reject relaxed bounds `?Trait` in the bounds of trait aliases. Just like `trait Trait {}` doesn't mean `trait Trait: Sized {}` and we therefore reject `trait Trait: ?Sized {}`, `trait Trait =;` (sic!) doesn't mean `trait Trait = Sized;` (never did!) and as a logical consequence `trait Trait = ?Sized;` is meaningless and should be forbidden. * Don't permit `?Sized` in more places (e.g., supertrait bounds, trait object types) if feature `more_maybe_bounds` is enabled. That internal feature is only meant to allow the user to define & use *new* default traits (that have fewer rules to follow for now to ease experimentation). * Unconditionally check that the `Trait` in `?Trait` is a default trait. Previously, we would only perform this check in selected places which was very brittle and led to bugs slipping through. * Slightly improve diagnostics.

Further tighten up relaxed bounds Follow-up to rust-lang#142693, rust-lang#135331 and rust-lang#135841. Fixes rust-lang#143122. * Reject relaxed bounds `?Trait` in the bounds of trait aliases. Just like `trait Trait {}` doesn't mean `trait Trait: Sized {}` and we therefore reject `trait Trait: ?Sized {}`, `trait Trait =;` (sic!) doesn't mean `trait Trait = Sized;` (never did!) and as a logical consequence `trait Trait = ?Sized;` is meaningless and should be forbidden. * Don't permit `?Sized` in more places (e.g., supertrait bounds, trait object types) if feature `more_maybe_bounds` is enabled. That internal feature is only meant to allow the user to define & use *new* default traits (that have fewer rules to follow for now to ease experimentation). * Unconditionally check that the `Trait` in `?Trait` is a default trait. Previously, we would only perform this check in selected places which was very brittle and led to bugs slipping through. * Slightly improve diagnostics.

Rollup merge of #147734 - fmease:tighten-relaxed, r=lcnr Further tighten up relaxed bounds Follow-up to #142693, #135331 and #135841. Fixes #143122. * Reject relaxed bounds `?Trait` in the bounds of trait aliases. Just like `trait Trait {}` doesn't mean `trait Trait: Sized {}` and we therefore reject `trait Trait: ?Sized {}`, `trait Trait =;` (sic!) doesn't mean `trait Trait = Sized;` (never did!) and as a logical consequence `trait Trait = ?Sized;` is meaningless and should be forbidden. * Don't permit `?Sized` in more places (e.g., supertrait bounds, trait object types) if feature `more_maybe_bounds` is enabled. That internal feature is only meant to allow the user to define & use *new* default traits (that have fewer rules to follow for now to ease experimentation). * Unconditionally check that the `Trait` in `?Trait` is a default trait. Previously, we would only perform this check in selected places which was very brittle and led to bugs slipping through. * Slightly improve diagnostics.

Further tighten up relaxed bounds Follow-up to rust-lang/rust#142693, rust-lang/rust#135331 and rust-lang/rust#135841. Fixes rust-lang/rust#143122. * Reject relaxed bounds `?Trait` in the bounds of trait aliases. Just like `trait Trait {}` doesn't mean `trait Trait: Sized {}` and we therefore reject `trait Trait: ?Sized {}`, `trait Trait =;` (sic!) doesn't mean `trait Trait = Sized;` (never did!) and as a logical consequence `trait Trait = ?Sized;` is meaningless and should be forbidden. * Don't permit `?Sized` in more places (e.g., supertrait bounds, trait object types) if feature `more_maybe_bounds` is enabled. That internal feature is only meant to allow the user to define & use *new* default traits (that have fewer rules to follow for now to ease experimentation). * Unconditionally check that the `Trait` in `?Trait` is a default trait. Previously, we would only perform this check in selected places which was very brittle and led to bugs slipping through. * Slightly improve diagnostics.

Rollup of 9 pull requests Successful merges: - rust-lang/rust#138554 (Distinguish delim kind to decide whether to emit unexpected closing delimiter) - rust-lang/rust#142673 (Show the offset, length and memory of uninit read errors) - rust-lang/rust#142693 (More robustly deal with relaxed bounds and improve their diagnostics) - rust-lang/rust#143382 (stabilize `const_slice_reverse`) - rust-lang/rust#143928 (opt-dist: make llvm builds optional) - rust-lang/rust#143961 (Correct which exploit mitigations are enabled by default) - rust-lang/rust#144050 (Fix encoding of link_section and no_mangle cross crate) - rust-lang/rust#144059 (Refactor `CrateLoader` into the `CStore`) - rust-lang/rust#144123 (Generalize `unsize` and `unsize_into` destinations) r? `@ghost` `@rustbot` modify labels: rollup

@davidtwco

…ease Eagerly decide whether relaxed bounds are allowed or not r? @davidtwco or @fmease Previously introduced in rust-lang#142693 by @fmease I am trying to resolve https://github.com/rust-lang/rust/blob/d7986943e496ccb07987f4ad83c6f7033d725861/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs#L196, but then got into a rabbit hole somehwere. I think this PR further unblocks resolving that FIXME, because it makes it easier to reason about whether we should be reporting an error about duplicate bounds or about relaxed bounds in general

@davidtwco

Rollup merge of #157305 - oli-obk:relaxed-bounds-maybe, r=fmease Eagerly decide whether relaxed bounds are allowed or not r? @davidtwco or @fmease Previously introduced in #142693 by @fmease I am trying to resolve https://github.com/rust-lang/rust/blob/d7986943e496ccb07987f4ad83c6f7033d725861/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs#L196, but then got into a rabbit hole somehwere. I think this PR further unblocks resolving that FIXME, because it makes it easier to reason about whether we should be reporting an error about duplicate bounds or about relaxed bounds in general

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 18, 2025

fmease force-pushed the unbound-bettering branch from 8d31700 to 4634541 Compare June 18, 2025 20:27

fmease changed the title ~~[WIP] unbound bettering (refactoring)~~ [WIP] unbound bettering Jun 18, 2025

fmease force-pushed the unbound-bettering branch 2 times, most recently from 69e237d to 03d01fa Compare June 19, 2025 02:46

fmease added the rla-silenced Silences rust-log-analyzer postings to the PR it's added on. label Jun 19, 2025

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fmease mentioned this pull request Jun 19, 2025

Sized hierarchy: PointeeSized bounds aren't fully validated during HIR ty lowering #142718

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fmease force-pushed the unbound-bettering branch 3 times, most recently from 8a6f65d to 04dad4e Compare June 20, 2025 21:17

fmease changed the title ~~[WIP] unbound bettering~~ More robustly deal with relaxed bounds and improve their diagnostics Jun 20, 2025

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rust-bors Bot added a commit that referenced this pull request Jun 20, 2025

Auto merge of #142693 - fmease:unbound-bettering, r=<try>

bfa10de

More robustly deal with relaxed bounds and improve their diagnostics Scaffolding for #135229 (CC #135331) Fixes #136944. Fixes #142718.

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 20, 2025

fmease mentioned this pull request Jun 20, 2025

Rehome tests in tests/ui/ to accurate subdirectories #142808

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Jun 21, 2025

bors added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Jun 27, 2025

fmease mentioned this pull request Jun 27, 2025

We don't fully validate relaxed trait bounds on the RHS of trait aliases (should we actually reject them outright?) #143122

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bors 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 Jul 18, 2025

fmease mentioned this pull request Jul 18, 2025

Reject relaxed bounds inside associated type bounds (ATB) #135331

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fmease removed the rla-silenced Silences rust-log-analyzer postings to the PR it's added on. label Jul 18, 2025

This was referenced Jul 18, 2025

Rollup of 10 pull requests #144138

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Rollup of 9 pull requests #144145

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bors merged commit f38891e into rust-lang:master Jul 19, 2025
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rustbot added this to the 1.90.0 milestone Jul 19, 2025

fmease deleted the unbound-bettering branch July 19, 2025 10:07

matthiaskrgr mentioned this pull request Jul 21, 2025

ICE: dyn !Sized #144241

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davidtwco mentioned this pull request Jul 24, 2025

Tracking Issue for Sized Hierarchy #144404

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fmease mentioned this pull request Aug 26, 2025

default auto traits: use default supertraits instead of Self: Trait bounds on associated items #145879

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fmease mentioned this pull request Oct 15, 2025

Further tighten up relaxed bounds #147734

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oli-obk mentioned this pull request Jun 2, 2026

Eagerly decide whether relaxed bounds are allowed or not #157305

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More robustly deal with relaxed bounds and improve their diagnostics#142693

More robustly deal with relaxed bounds and improve their diagnostics#142693
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rust-timer commented Jun 21, 2025

Overall result: ❌ regressions - please read the text below

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