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Sized Hierarchy #137944

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Sized Hierarchy #137944

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@davidtwco davidtwco commented Mar 3, 2025 •
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This patch implements rust-lang/rfcs#3729. It introduces two new traits to the standard library, MetaSized and PointeeSized, and makes MetaSized and Sized into const traits (relying on unstable feature(const_trait_impl)). See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.

These traits are unstable (as is their constness), so users cannot refer to them without opting-in to feature(sized_hierarchy). These traits are not behind cfgs as this would make implementation unfeasible, there would simply be too many cfgs required to add the necessary bounds everywhere. So, like Sized, these traits are automatically implemented by the compiler.

RFC 3729 describes migrations which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:

  • On the current edition, Sized is rewritten as const Sized
    • If the sized_hierarchy feature is enabled, then an edition migration lint to rewrite the bound to const Sized will be emitted.
    • On the next edition, non-const Sized will resume being the default bound.
  • On the current edition, ?Sized is rewritten as const MetaSized
    • If the sized_hierarchy feature is enabled, then an edition migration lint to rewrite the bound to const MetaSized will be emitted.
    • On the next edition, writing ?Sized will be prohibited.
  • On the current edition, const MetaSized is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.
    • If the sized_hierarchy feature is enabled, then an edition migration lint to add an explicit const MetaSized supertrait will be emitted.
    • On the next edition, there is no default const MetaSized supertrait.

Each of these migrations is not conditional on whether the item being migrated needs the migration to the stricter bound - this would be preferable but is not yet implemented (if it is possible to implement). All diagnostic output should remain the same (showing ?Sized even if the compiler sees const MetaSized) unless the sized_hierarchy feature is enabled.

Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax Deref::Target (this will be investigated separately).

It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Only once sized_hierarchy is stabilised would edition migration lints start to be emitted and diagnostic output show the "real" sizedness traits behind-the-scenes, rather than ?Sized. Some details might leak through due to the standard library relaxations, but this has not been observed in test output.

Notes:

  • Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
  • This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
    • Each commit has a short description describing its purpose.
    • This patch is large but it's primarily in the test suite (library: +573/-184, compiler: +1268/-310, tests: +3720/-452).
  • It is expected that this will have performance regressions initially and I'll aim to resolve those prior to merging if possible.
    • I'd appreciate feedback on how best to go about this from those familiar with the type system.
  • On my local machine, this passes all of the test suites, a stage two build and a tidy check.
  • PointeeSized is a different name from the RFC just to make it more obvious that it is different from std::ptr::Pointee but all the names are yet to be bikeshed anyway.

Fixes #79409.

r? @ghost (I'll discuss this with relevant teams to find a reviewer)

@rustbot rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) A-run-make Area: port run-make Makefiles to rmake.rs A-rustdoc-json Area: Rustdoc JSON backend A-rustdoc-search Area: Rustdoc's search feature PG-exploit-mitigations Project group: Exploit mitigations 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. T-libs Relevant to the library team, which will review and decide on the PR/issue. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. T-rustdoc-frontend Relevant to the rustdoc-frontend team, which will review and decide on the web UI/UX output. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Mar 3, 2025
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davidtwco commented Mar 3, 2025 •
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I can reproduce this locally but I have no idea why it would be related to this patch. Clippy needed adjusting.

@rustbot rustbot added the T-bootstrap Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap) label Mar 3, 2025
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@traviscross traviscross added the T-lang Relevant to the language team, which will review and decide on the PR/issue. label Mar 4, 2025
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cc @rust-lang/lang

@fee1-dead fee1-dead self-assigned this Mar 4, 2025
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tmiasko commented Mar 4, 2025

Does this perhaps fix #127336 by rejecting it?

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Does this perhaps fix #127336 by rejecting it?

It doesn't currently.

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Undrafting now that CI passes

davidtwco added 25 commits March 8, 2025 22:52
@davidtwco
feature/passes: add rustc_non_const_sized
6bee501 
While there are no non-`const Sized` types in the language, this testing
attribute will make it possible to force this for testing purposes.
@davidtwco
library/trait_sel: make {Meta,}Sized const
34e697b 
Makes `{Meta,}Sized` into const traits and implements them in the trait
solvers so everything is `Sized` except ADTs with the
`rustc_non_const_sized` attribute.
@davidtwco
aux: add const {Meta,}Sized to minicore
cc66f3c 
Now that `MetaSized` and `Sized` are const traits, this must be reflected
in minicore.
@davidtwco
tests: const {Meta,}Sized in non-minicore
078c2a0 
Now that `MetaSized` and `Sized` are const traits, this must be reflected
in tests without minicore which define these language items.
@davidtwco
hir_analysis: change {Meta,}Sized bounds to const
2fa2e6d 
With const sizedness traits, the correct migration is from `Sized`
to `const Sized` and from `?Sized` to `const MetaSized`.
@davidtwco
hir_analysis: specialisation w/ host effect preds
0ac9754 
There are some uses of `min_specialization` in the standard library which
now see `HostEffectPredicate` - this shouldn't prevent specialization
for the sizedness marker traits that are now const.
@davidtwco
next_trait_solver: merge trivial builtin impls
c8b18b8 
Some of the host effect predicates end up with
`TraitGoalProvenVia::ParamEnv` combined with
`CandidateSource::BuiltinImpl` and are discarded as a consequence.

This commit special-cases `BuiltinImplSource::Trivial` to avoid this -
that might not be precisely the correct fix but it is unclear what that
would be.

Without this, the following tests fail:

- tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.rs#next
- tests/ui/associated-types/defaults-suitability.rs#next
- tests/ui/associated-types/defaults-unsound-62211-1.rs#next
- tests/ui/associated-types/defaults-unsound-62211-2.rs#next
- tests/ui/associated-types/imply-relevant-nested-item-bounds.rs#next
- tests/ui/associated-types/imply-relevant-nested-item-bounds-2.rs#next
- tests/ui/associated-types/issue-63593.rs#next
- tests/ui/associated-types/issue-54108.rs#next
- tests/ui/async-await/async-closures/constrained-but-no-upvars-yet.rs#next
- tests/ui/async-await/async-closures/is-not-fn.rs#next
- tests/ui/async-await/async-closures/is-fn.rs#next
- tests/ui/async-await/async-closures/once.rs#next
- tests/ui/async-await/async-closures/signature-inference-from-two-part-bound.rs#next
- tests/ui/async-await/async-fn/higher-ranked-async-fn.rs#next
- tests/ui/async-await/async-fn/project.rs#next
- tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.rs#next
- tests/ui/async-await/send-bound-async-closure.rs#next
- tests/ui/borrowck/implied-bound-from-impl-header.rs#next
- tests/ui/borrowck/implied-bound-from-normalized-arg.rs#next
- tests/ui/borrowck/issue-103095.rs#next
- tests/ui/closures/deduce-signature/deduce-from-opaque-type-after-norm.rs#next
- tests/ui/closures/deduce-signature/infer-higher-ranked-signature.rs#next
- tests/ui/closures/deduce-signature/infer-signature-from-impl.rs#next
- tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.rs#next
- tests/ui/closures/deduce-signature/supertrait-signature-inference-issue-23012.rs#next
- tests/ui/closures/supertrait-hint-references-assoc-ty.rs#next
- tests/ui/coherence/coherence-overlap-negate-use-feature-gate.rs
- tests/ui/coherence/occurs-check/opaques.rs#next
- tests/ui/coherence/occurs-check/associated-type.rs#next
- tests/ui/coherence/orphan-check-alias.rs#next
- tests/ui/coherence/orphan-check-projections-nested.rs#next
- tests/ui/coherence/orphan-check-projections-not-covering-ambiguity.rs#next
- tests/ui/coherence/orphan-check-projections-not-covering.rs#next
- tests/ui/coroutine/gen_block_iterate.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/nested.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/simple.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/stacked.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs#next
- tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.rs#next
- tests/ui/generic-associated-types/ambig-hr-projection-issue-93340.rs#next
- tests/ui/generic-associated-types/assume-gat-normalization-for-nested-goals.rs#next
- tests/ui/generic-associated-types/issue-74816.rs#next
- tests/ui/generic-associated-types/issue-74824.rs#next
- tests/ui/generic-associated-types/issue-91883.rs#next
- tests/ui/generic-associated-types/rigid-hr-projection-issue-93340.rs#next
- tests/ui/generic-const-items/const-trait-impl.rs
- tests/ui/higher-ranked/builtin-closure-like-bounds.rs#next
- tests/ui/higher-ranked/closure-bound-codegen-ice.rs#next
- tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-1.rs#next
- tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-2.rs#next
- tests/ui/higher-ranked/leak-check/candidate-from-env-universe-err-project.rs#next
- tests/ui/higher-ranked/leak-check/leak-check-in-selection-2.rs#next
- tests/ui/higher-ranked/leak-check/leak-check-in-selection-3.rs#next
- tests/ui/higher-ranked/leak-check/leak-check-in-selection-4-hr-nested.rs#next
- tests/ui/higher-ranked/leak-check/leak-check-in-selection-5-ambig.rs#next
- tests/ui/higher-ranked/leak-check/leak-check-in-selection-6-ambig-unify.rs#next
- tests/ui/higher-ranked/trait-bounds/future.rs#next
- tests/ui/higher-ranked/trait-bounds/rigid-equate-projections-in-higher-ranked-fn-signature.rs#next
- tests/ui/higher-ranked/trait-bounds/normalize-under-binder/norm-before-method-resolution-opaque-type.rs#next
- tests/ui/impl-trait/auto-trait-selection-freeze.rs#next
- tests/ui/impl-trait/auto-trait-selection.rs#next
- tests/ui/impl-trait/call_method_on_inherent_impl.rs#next
- tests/ui/impl-trait/call_method_ambiguous.rs#next
- tests/ui/impl-trait/dyn-trait-elided-two-inputs-ref-assoc.rs#next
- tests/ui/impl-trait/hidden-type-is-opaque-2.rs#next
- tests/ui/impl-trait/in-trait/alias-bounds-when-not-wf.rs
- tests/ui/impl-trait/in-trait/default-body-with-rpit.rs#next
- tests/ui/impl-trait/in-trait/dyn-compatibility-sized.rs#next
- tests/ui/impl-trait/in-trait/false-positive-predicate-entailment-error.rs#next
- tests/ui/impl-trait/in-trait/refine-normalize.rs#next
- tests/ui/impl-trait/issue-103181-1.rs#next
- tests/ui/impl-trait/method-resolution2.rs#next
- tests/ui/impl-trait/recursive-bound-eval.rs#next
- tests/ui/impl-trait/unsized_coercion.rs#next
- tests/ui/issues/issue-15734.rs#next
- tests/ui/methods/fulfillment-disqualifies-method.rs#next
- tests/ui/methods/leak-check-disquality.rs#next
- tests/ui/nll/check-normalized-sig-for-wf.rs#next
- tests/ui/panics/abort-on-panic.rs#next
- tests/ui/specialization/source-impl-requires-constraining-predicates.rs#next
- tests/ui/specialization/source-impl-requires-constraining-predicates-ambig.rs#next
- tests/ui/specialization/specialization-default-items-drop-coherence.rs#next
- tests/ui/traits/const-traits/assoc-type-const-bound-usage-0.rs#next
- tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail-2.rs#next
- tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail.rs#next
- tests/ui/traits/const-traits/assoc-type.rs#next
- tests/ui/traits/const-traits/call-const-in-tilde-const.rs
- tests/ui/traits/const-traits/call-generic-method-dup-bound.rs
- tests/ui/traits/const-traits/call-generic-method-nonconst.rs
- tests/ui/traits/const-traits/const-bound-in-host.rs
- tests/ui/traits/const-traits/const-bound-on-not-const-associated-fn.rs
- tests/ui/traits/const-traits/const-cond-for-rpitit.rs
- tests/ui/traits/const-traits/const-drop-fail.rs#new_precise
- tests/ui/traits/const-traits/const-drop-fail.rs#new_stock
- tests/ui/traits/const-traits/const-drop.rs#precise
- tests/ui/traits/const-traits/const-drop.rs#stock
- tests/ui/traits/const-traits/const-in-closure.rs
- tests/ui/traits/const-traits/const-opaque.rs#no
- tests/ui/traits/const-traits/const-impl-trait.rs
- tests/ui/traits/const-traits/const-opaque.rs#yes
- tests/ui/traits/const-traits/dont-ice-on-const-pred-for-bounds.rs
- tests/ui/traits/const-traits/infer-fallback.rs
- tests/ui/traits/const-traits/issue-92230-wf-super-trait-env.rs
- tests/ui/traits/const-traits/item-bound-entailment-fails.rs
- tests/ui/traits/const-traits/item-bound-entailment.rs
- tests/ui/traits/const-traits/minicore-drop-without-feature-gate.rs#no
- tests/ui/traits/const-traits/minicore-deref-fail.rs
- tests/ui/traits/const-traits/minicore-const-fn-early-bound.rs
- tests/ui/traits/const-traits/minicore-drop-fail.rs
- tests/ui/traits/const-traits/minicore-drop-without-feature-gate.rs#yes
- tests/ui/traits/const-traits/minicore-fn-fail.rs
- tests/ui/traits/const-traits/minicore-works.rs
- tests/ui/traits/const-traits/predicate-entailment-passes.rs
- tests/ui/traits/const-traits/predicate-entailment-fails.rs
- tests/ui/traits/const-traits/super-traits-fail-2.rs#nn
- tests/ui/traits/const-traits/super-traits-fail-2.rs#ny
- tests/ui/traits/const-traits/staged-api.rs
- tests/ui/traits/const-traits/super-traits-fail-3.rs#nnn
- tests/ui/traits/const-traits/super-traits-fail-2.rs#yn
- tests/ui/traits/const-traits/super-traits-fail-2.rs#yy
- tests/ui/traits/const-traits/super-traits-fail-3.rs#nny
- tests/ui/traits/const-traits/super-traits-fail-3.rs#nyy
- tests/ui/traits/const-traits/super-traits-fail-3.rs#nyn
- tests/ui/traits/const-traits/super-traits-fail-3.rs#yyy
- tests/ui/traits/const-traits/super-traits-fail-3.rs#ynn
- tests/ui/traits/const-traits/super-traits-fail-3.rs#yyn
- tests/ui/traits/const-traits/super-traits-fail-3.rs#yny
- tests/ui/traits/const-traits/super-traits.rs
- tests/ui/traits/const-traits/tilde-const-assoc-fn-in-trait-impl.rs
- tests/ui/traits/const-traits/tilde-const-inherent-assoc-const-fn.rs
- tests/ui/traits/const-traits/tilde-const-in-struct-args.rs
- tests/ui/traits/const-traits/trait-where-clause-self-referential.rs
- tests/ui/traits/const-traits/trait-where-clause-const.rs
- tests/ui/traits/const-traits/unsatisfied-const-trait-bound.rs
- tests/ui/traits/negative-bounds/opaque-type-unsatisfied-bound.rs
- tests/ui/traits/negative-impls/negative-impl-normalizes-to.rs#next
- tests/ui/traits/next-solver/alias-bound-preference.rs#next
- tests/ui/traits/next-solver/alias-relate/alias_eq_cant_be_furthur_normalized.rs
- tests/ui/traits/next-solver/alias-eq-in-canonical-response.rs
- tests/ui/traits/next-solver/alias-bound-unsound.rs
- tests/ui/traits/next-solver/alias-relate/alias_eq_simple.rs
- tests/ui/traits/next-solver/alias-relate/opaque-hidden-ty-is-rigid-alias.rs
- tests/ui/traits/next-solver/alias-sub.rs
- tests/ui/traits/next-solver/alias-relate/deeply-nested-no-hang.rs
- tests/ui/traits/next-solver/assembly/ambig-projection-self-is-ambig.rs
- tests/ui/traits/next-solver/assembly/assemble-normalizing-self-ty-impl-ambiguity.rs
- tests/ui/traits/next-solver/assembly/candidates-equal-modulo-norm-1.rs
- tests/ui/traits/next-solver/async.rs#fail
- tests/ui/traits/next-solver/assembly/candidates-equal-modulo-norm-2.rs
- tests/ui/traits/next-solver/async.rs#pass
- tests/ui/traits/next-solver/assembly/param-env-alias-bound-conflict.rs
- tests/ui/traits/next-solver/auto-with-drop_tracking_mir.rs#pass
- tests/ui/traits/next-solver/assembly/runaway-impl-candidate-selection.rs
- tests/ui/traits/next-solver/auto-with-drop_tracking_mir.rs#fail
- tests/ui/traits/next-solver/canonical/effect-var.rs
- tests/ui/traits/next-solver/canonical/int-var-eq-in-response.rs
- tests/ui/traits/next-solver/builtin-fn-must-return-sized.rs
- tests/ui/traits/next-solver/closure-inference-guidance.rs
- tests/ui/traits/next-solver/closure-signature-inference-2.rs
- tests/ui/traits/next-solver/closure-signature-inference-hr-ambig-alias-naming-self.rs#next
- tests/ui/traits/next-solver/coerce-ambig-alias-to-rigid-alias.rs
- tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-norm-overflow.rs
- tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-1.rs
- tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-3.rs
- tests/ui/traits/next-solver/coherence/trait_ref_is_knowable-normalization-2.rs
- tests/ui/traits/next-solver/const-param-placeholder.rs#pass
- tests/ui/traits/next-solver/const-param-placeholder.rs#fail
- tests/ui/traits/next-solver/constrain-alias-goals-in-unsize.rs
- tests/ui/traits/next-solver/coroutine.rs#pass
- tests/ui/traits/next-solver/coroutine.rs#fail
- tests/ui/traits/next-solver/cycles/coinduction/fixpoint-exponential-growth.rs
- tests/ui/traits/next-solver/cycles/double-cycle-inductive-coinductive.rs
- tests/ui/traits/next-solver/cycles/inductive-cycle-but-err.rs
- tests/ui/traits/next-solver/cycles/inductive-cycle-but-ok.rs
- tests/ui/traits/next-solver/cycles/inductive-fixpoint-hang.rs
- tests/ui/traits/next-solver/cycles/leak-check-coinductive-cycle.rs
- tests/ui/traits/next-solver/cycles/inductive-not-on-stack.rs
- tests/ui/traits/next-solver/cycles/mixed-cycles-1.rs
- tests/ui/traits/next-solver/cycles/mixed-cycles-2.rs
- tests/ui/traits/next-solver/cycles/provisional-cache-impacts-behavior.rs
- tests/ui/traits/next-solver/cycles/provisional-result-done.rs
- tests/ui/traits/next-solver/cycles/cycle-modulo-ambig-aliases.rs
- tests/ui/traits/next-solver/destruct.rs
- tests/ui/traits/next-solver/diagnostics/alias_relate_error_uses_structurally_normalize.rs
- tests/ui/traits/next-solver/diagnostics/deeply-normalize-type-expectation.rs
- tests/ui/traits/next-solver/diagnostics/coerce-in-may-coerce.rs
- tests/ui/traits/next-solver/diagnostics/point-at-failing-nested.rs
- tests/ui/traits/next-solver/diagnostics/projection-trait-ref.rs
- tests/ui/traits/next-solver/diagnostics/dont-pick-fnptr-bound-as-leaf.rs#next
- tests/ui/traits/next-solver/dont-loop-fulfill-on-region-constraints.rs
- tests/ui/traits/next-solver/elaborate-item-bounds.rs
- tests/ui/traits/next-solver/dont-normalize-proj-with-error.rs
- tests/ui/traits/next-solver/dyn-incompatibility.rs
- tests/ui/traits/next-solver/fn-trait-closure.rs
- tests/ui/traits/next-solver/fn-trait.rs
- tests/ui/traits/next-solver/generalize/bivariant-alias.rs#next
- tests/ui/traits/next-solver/generalize/equating-projection-cyclically.rs
- tests/ui/traits/next-solver/generalize/hr-alias-non-hr-alias-self-ty-1.rs#next
- tests/ui/traits/next-solver/generalize/hr-alias-universe-lowering-ambiguity.rs
- tests/ui/traits/next-solver/generalize/occurs-check-nested-alias.rs#next
- tests/ui/traits/next-solver/generalize/instantiate-canonical-occurs-check-failure.rs
- tests/ui/traits/next-solver/generalize/hr-alias-non-hr-alias-self-ty-2.rs#next
- tests/ui/traits/next-solver/higher-ranked-dyn-bounds.rs
- tests/ui/traits/next-solver/issue-118950-root-region.rs
- tests/ui/traits/next-solver/iter-filter-projection.rs
- tests/ui/traits/next-solver/lazy-nested-obligations-2.rs
- tests/ui/traits/next-solver/lazy-nested-obligations-3.rs
- tests/ui/traits/next-solver/nested-obligations-with-bound-vars-gat.rs
- tests/ui/traits/next-solver/nested-alias-bound.rs
- tests/ui/traits/next-solver/method/path_lookup_wf_constraints.rs
- tests/ui/traits/next-solver/non-wf-ret.rs
- tests/ui/traits/next-solver/normalization-shadowing/alias-bound-shadowed-by-env.rs
- tests/ui/traits/next-solver/normalization-shadowing/discard-impls-shadowed-by-env-1.rs
- tests/ui/traits/next-solver/normalization-shadowing/discard-impls-shadowed-by-env-3.rs
- tests/ui/traits/next-solver/normalization-shadowing/discard-impls-shadowed-by-env-2.rs#next
- tests/ui/traits/next-solver/normalization-shadowing/param-env-impl-conflict.rs
- tests/ui/traits/next-solver/normalization-shadowing/normalizes_to_ignores_unnormalizable_candidate.rs
- tests/ui/traits/next-solver/normalization-shadowing/param-candidate-shadows-project.rs
- tests/ui/traits/next-solver/normalize-in-implied_outlives_bounds.rs
- tests/ui/traits/next-solver/normalize/normalize-param-env-3.rs
- tests/ui/traits/next-solver/normalize/normalize-param-env-1.rs
- tests/ui/traits/next-solver/normalize/normalize-async-closure-in-trait.rs
- tests/ui/traits/next-solver/normalize/normalize-param-env-2.rs
- tests/ui/traits/next-solver/normalize/normalize-param-env-4.rs#next
- tests/ui/traits/next-solver/normalize/normalize-rcvr-for-inherent.rs
- tests/ui/traits/next-solver/normalize/normalize-path-for-method.rs
- tests/ui/traits/next-solver/normalize/normalize-region-obligations.rs#hrtb
- tests/ui/traits/next-solver/normalize/normalize-region-obligations.rs#normalize_obligation
- tests/ui/traits/next-solver/normalize/normalize-region-obligations.rs#normalize_param_env
- tests/ui/traits/next-solver/normalize/normalize-type-outlives-in-param-env.rs
- tests/ui/traits/next-solver/normalize/ambig-goal-infer-in-type-oulives.rs
- tests/ui/traits/next-solver/normalize/param-env-trait-candidate-2.rs
- tests/ui/traits/next-solver/normalize/two-projection-param-candidates-are-ambiguous.rs
- tests/ui/traits/next-solver/opaques/dont-remap-tait-substs.rs
- tests/ui/traits/next-solver/opaques/select-alias-bound-as-param.rs
- tests/ui/traits/next-solver/opportunistic-region-resolve.rs
- tests/ui/traits/next-solver/opaques/no-define-in-wf-check.rs#next
- tests/ui/traits/next-solver/overflow/exponential-trait-goals.rs
- tests/ui/traits/next-solver/normalize/param-env-trait-candidate-1.rs
- tests/ui/traits/next-solver/overflow/global-cache.rs
- tests/ui/traits/next-solver/overflow/nalgebra-hang.rs#next
- tests/ui/traits/next-solver/overflow/recursive-self-normalization.rs
- tests/ui/traits/next-solver/overflow/recursive-self-normalization-2.rs
- tests/ui/traits/next-solver/pointee.rs
- tests/ui/traits/next-solver/pointer-like.rs
- tests/ui/traits/next-solver/prefer-candidate-no-constraints.rs
- tests/ui/traits/next-solver/prefer-param-env-on-ambiguity.rs
- tests/ui/traits/next-solver/projection-discr-kind.rs
- tests/ui/traits/next-solver/specialization-unconstrained.rs
- tests/ui/traits/next-solver/specialization-transmute.rs
- tests/ui/traits/next-solver/typeck/guide-ctors.rs
- tests/ui/traits/next-solver/try-example.rs
- tests/ui/traits/next-solver/typeck/normalize-in-upvar-collection.rs
- tests/ui/traits/next-solver/typeck/resolve-before-checking-builtin-ptr.rs
- tests/ui/traits/next-solver/typeck/resolve-before-checking-never.rs
- tests/ui/traits/next-solver/typeck/structurally-resolve-in-probe_adt.rs
- tests/ui/traits/next-solver/typeck/resolve-expectations.rs
- tests/ui/traits/next-solver/winnow-specializing-impls.rs
- tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.rs#next
- tests/ui/traits/normalize-supertrait.rs#next
- tests/ui/traits/pointee-normalize-equate.rs#next
- tests/ui/traits/reservation-impl/non-lattice-ok.rs#next
- tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs#next
- tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs#next
- tests/ui/traits/trait-upcasting/normalization.rs#next
- tests/ui/traits/trait-upcasting/prefer-lower-candidates.rs#next
- tests/ui/traits/winnowing/global-non-global-env-1.rs#next
- tests/ui/traits/winnowing/global-non-global-env-3.rs#next
- tests/ui/traits/winnowing/global-non-global-env-2.rs#next
- tests/ui/traits/winnowing/global-non-global-env-4.rs#next
- tests/ui/transmutability/primitives/bool.rs#next
- tests/ui/transmutability/primitives/unit.rs#next
- tests/ui/type-alias-impl-trait/assoc-type-const.rs#next
- tests/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.rs#next
- tests/ui/type-alias-impl-trait/issue-78450.rs#next
- tests/ui/type-alias-impl-trait/issue-84660-unsoundness.rs#next
- tests/ui/type-alias-impl-trait/method_resolution3.rs#next
- tests/ui/type-alias-impl-trait/method_resolution4.rs#next
- tests/ui/type-alias-impl-trait/nested_inference_failure.rs#next
- tests/ui/type-alias-impl-trait/normalize-hidden-types.rs#next
- tests/ui/type-alias-impl-trait/rpit_tait_equality_in_canonical_query.rs#next
- tests/ui/typeck/bad-index-due-to-nested.rs#next
- tests/ui/typeck/issue-116864.rs
- tests/ui/unsized/issue-75899.rs#next
- tests/ui/transmutability/primitives/numbers.rs#next
- tests/ui/wf/wf-in-where-clause-static.rs#next
@davidtwco
trait_sel: re-order host effect evaluations
aabd806 
When evaluating a host effect predicate on an opaque in `addr2line`,
running `evaluate_host_effect_from_bounds` first would create an opaque
type which wouldn't be removed from opaque type storage and that would
cause a delayed bug - creating a small reproduction of this has been
tricky but if `builtin_impls` checking is moved below
`evaluate_host_effect_from_item_bounds` then it will trigger.

The correct fix is probably to work out why the opaque type is created
and then not used, but this was particularly tricky. Given that this root
cause wasn't identified, writing a test case proved difficult.
@davidtwco
trait_sel: const {Meta,}Sized in impl headers
bc1679b 
Now that sizedness traits have been made const, pretty printing of impl
headers should print the constness of the sizedness trait.
@davidtwco
middle: const {Meta,Pointee}Sized in opaques
d9ccc87 
These traits are now const and that needs to be reflected in their
printing in opaques.
@davidtwco
trait_sel: remove intercrate mode assertion
3b765b8 
This causes a bunch of tests to fail and everything appears to work
without it:

- tests/ui/coherence/orphan-check-opaque-types-not-covering.rs
- tests/ui/coherence/orphan-check-projections-covering.rs
- tests/ui/coherence/orphan-check-projections-unsat-bounds.rs#classic
- tests/ui/coherence/orphan-check-weak-aliases-not-covering.rs
- tests/ui/coherence/orphan-check-weak-aliases-covering.rs#classic
- tests/ui/specialization/issue-43037.rs#negative
- tests/ui/specialization/issue-43037.rs#current
- tests/ui/type-alias-impl-trait/coherence.rs#classic
@davidtwco
tests: bless remaining tests
57ace42 
These tests just need blessing, they don't have any interesting behaviour
changes.
@davidtwco
library: add {Pointee,Meta}Sized to next prelude
969a4c1 
Its strange to have to import sizedness traits, so add them to the
prelude in the next edition.
@davidtwco
hir_analysis: edition migration
d695686 
Implement the edition migration required by these changes - `?Sized`
becoming `const MetaSized`, `Sized` becoming `const Sized` and a
`const MetaSized` supertrait.
@davidtwco
lint-docs: add future edition group
a75ecf3 
This should have been included in rust-lang#137606.
@davidtwco
tests: move crashes/79409.rs to ui suite
913b330 
This test no longer crashes the compiler as `Box` no longer accepts
`PointeeSized`-types. It eventually could, but not because of
`Deref::Target` currently, so this doesn't fail anymore and there wasn't
an obvious to add new types to make it continue to fail because `Deref`
is special.
@davidtwco
rustdoc: update no_core tests w/ new traits
92914c1 
Some rustdoc tests are `no_core` and need to have `MetaSized` and
`PointeeSized` added to them. One or two tests used extern types and
needed further relaxations to work as before.
@davidtwco
rustdoc: skip MetaSized bounds
0c74815 
These should never be shown to users at the moment.
@davidtwco
clippy: update no_core tests w/ new traits
133691e 
One clippy test is `no_core` and needs to have `MetaSized` and
`PointeeSized` added to it.
@davidtwco
clippy: add MetaSized conditions
fd80683 
Existing lints that had special-casing for `Sized` predicates ought
to have these same special cases applied to `MetaSized` predicates.
@davidtwco
bootstrap: address lint failures
6eb24e3 
Unexpected Clippy lint triggering is fixed in previous commits but
is necessary for `cfg(bootstrap)`.
@davidtwco
miri: fix build
9682cc0 
It's unclear why this change in miri is necessary.
@davidtwco
miri: bless tests
e90a5a2 
These error messages include lines of the standard library which have
changed and so need updated.
@davidtwco
passes: propagate unstability for traits
d2286ca 
Unstability is propagated when staged API is not used and
`-Zforce-unstable-if-unmarked` is, but this only happened for const
functions not const traits, which ends up being an issue for some of the
minicore tests of codegen backends when introducing the sizedness traits.
@davidtwco
cranelift/gcc: add sizedness traits to minicore
94f4c5d 
As in many previous commits, adding the new traits and constness to
the minicore.
@rust-log-analyzer

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rustbot commented Mar 10, 2025

This PR changes a file inside tests/crashes. If a crash was fixed, please move into the corresponding ui subdir and add 'Fixes #' to the PR description to autoclose the issue upon merge.

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Thanks for the initial review @fee1-dead, addressed all of those comments now.

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ICE with unsizing an extern type
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