view-types: HIR lowering by scrabsha · Pull Request #158739 · rust-lang/rust

scrabsha · 2026-07-03T15:11:40Z

This PR implements the AST -> HIR lowering of view types and a few checks.

Tracking issue: #155938.

r? oli-obk

rustbot · 2026-07-03T15:11:44Z

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

clippy is developed in its own repository. If possible, consider making this change to rust-lang/rust-clippy instead.

cc @rust-lang/clippy

HIR ty lowering was modified

cc @fmease

rustfmt is developed in its own repository. If possible, consider making this change to rust-lang/rustfmt instead.

cc @rust-lang/rustfmt

rustbot · 2026-07-08T07:52:55Z

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.

scrabsha · 2026-07-08T07:57:51Z

^ rebase over latest main now that #156016 has been merged. the commits have not been edited.

rustbot · 2026-07-08T15:53:43Z

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

scrabsha · 2026-07-09T08:55:17Z

@rustbot ready

oli-obk

@bors r+ rollup

View changes since this review

…, r=oli-obk view-types: HIR lowering

…uwer Rollup of 17 pull requests Successful merges: - #158510 (Enable `static_position_independent_executables` on all gnu and musl targets) - #158541 (Move `std::io::Write` to `core::io`) - #158899 (Fix `unaligned_volatile_store` by removing `MemFlags::UNALIGNED`) - #155429 (Support `u128`/`i128` c-variadic arguments) - #156370 (Reject linked dylib EII default overrides) - #157153 (allow `Allocator`s to be used as `#[global_allocator]`s) - #158535 (Support `#[track_caller]` on EII declarations) - #158617 (allow mGCA const arguments to fall back to anon consts) - #158645 (Fix splat ICEs and ban it in closures) - #158988 (Redo `TokenStreamIter`) - #158347 (Improve generic parameters handling for #[diagnostic::on_const]) - #158722 (delegation: do not always inherit `ConstArgHasType` predicates) - #158739 (view-types: HIR lowering) - #158883 (tests: fix enum-match.rs to handle LLVM 23) - #158886 (Add documentation for the `no_std` attribute) - #158951 (Merge three `MaxUniverse`s into one) - #158961 (Reapply "LLVM 23: Run AssignGUIDPass in some places")

…, r=oli-obk view-types: HIR lowering

…uwer Rollup of 21 pull requests Successful merges: - #150946 (intrinsics: Add a fallback for non-const libm float functions) - #158510 (Enable `static_position_independent_executables` on all gnu and musl targets) - #158541 (Move `std::io::Write` to `core::io`) - #158899 (Fix `unaligned_volatile_store` by removing `MemFlags::UNALIGNED`) - #155429 (Support `u128`/`i128` c-variadic arguments) - #156370 (Reject linked dylib EII default overrides) - #156508 (Infer all anonymous lifetimes in assoc consts as `'static`) - #158617 (allow mGCA const arguments to fall back to anon consts) - #158645 (Fix splat ICEs and ban it in closures) - #158859 (Improve `-Zls` diagnostic message on `.rs` files) - #158988 (Redo `TokenStreamIter`) - #158347 (Improve generic parameters handling for #[diagnostic::on_const]) - #158722 (delegation: do not always inherit `ConstArgHasType` predicates) - #158739 (view-types: HIR lowering) - #158883 (tests: fix enum-match.rs to handle LLVM 23) - #158886 (Add documentation for the `no_std` attribute) - #158940 (Implement feature `char_to_u32`) - #158951 (Merge three `MaxUniverse`s into one) - #158961 (Reapply "LLVM 23: Run AssignGUIDPass in some places") - #158996 ([compiler] Implement `PartialOrd` via `Ord` for `Span` and newtype_indexes) - #159005 (Use `as_lang_item` instead of repeatedly matching)

…, r=oli-obk view-types: HIR lowering

…uwer Rollup of 24 pull requests Successful merges: - #150946 (intrinsics: Add a fallback for non-const libm float functions) - #158510 (Enable `static_position_independent_executables` on all gnu and musl targets) - #158541 (Move `std::io::Write` to `core::io`) - #158899 (Fix `unaligned_volatile_store` by removing `MemFlags::UNALIGNED`) - #156027 (Consider captured regions for opaque type region liveness.) - #156370 (Reject linked dylib EII default overrides) - #156508 (Infer all anonymous lifetimes in assoc consts as `'static`) - #157561 (rustdoc: do not include extra stuff in span) - #158617 (allow mGCA const arguments to fall back to anon consts) - #158645 (Fix splat ICEs and ban it in closures) - #158859 (Improve `-Zls` diagnostic message on `.rs` files) - #158988 (Redo `TokenStreamIter`) - #158347 (Improve generic parameters handling for #[diagnostic::on_const]) - #158384 (Allow BackwardIncompatibleDropHint in polonius legacy) - #158722 (delegation: do not always inherit `ConstArgHasType` predicates) - #158739 (view-types: HIR lowering) - #158877 (borrowck: Keep returned `path` from `best_blame_constraint()` consistent) - #158883 (tests: fix enum-match.rs to handle LLVM 23) - #158886 (Add documentation for the `no_std` attribute) - #158940 (Implement feature `char_to_u32`) - #158951 (Merge three `MaxUniverse`s into one) - #158961 (Reapply "LLVM 23: Run AssignGUIDPass in some places") - #158995 (Use REST API in linkchecker script) - #158996 ([compiler] Implement `PartialOrd` via `Ord` for `Span` and newtype_indexes)

…, r=oli-obk view-types: HIR lowering

Rollup of 24 pull requests Successful merges: - #150946 (intrinsics: Add a fallback for non-const libm float functions) - #158541 (Move `std::io::Write` to `core::io`) - #156027 (Consider captured regions for opaque type region liveness.) - #156370 (Reject linked dylib EII default overrides) - #156508 (Infer all anonymous lifetimes in assoc consts as `'static`) - #157561 (rustdoc: do not include extra stuff in span) - #158617 (allow mGCA const arguments to fall back to anon consts) - #158645 (Fix splat ICEs and ban it in closures) - #158859 (Improve `-Zls` diagnostic message on `.rs` files) - #158988 (Redo `TokenStreamIter`) - #158347 (Improve generic parameters handling for #[diagnostic::on_const]) - #158384 (Allow BackwardIncompatibleDropHint in polonius legacy) - #158722 (delegation: do not always inherit `ConstArgHasType` predicates) - #158739 (view-types: HIR lowering) - #158877 (borrowck: Keep returned `path` from `best_blame_constraint()` consistent) - #158883 (tests: fix enum-match.rs to handle LLVM 23) - #158886 (Add documentation for the `no_std` attribute) - #158940 (Implement feature `char_to_u32`) - #158951 (Merge three `MaxUniverse`s into one) - #158960 (Fix bootstrap submodule path prefix matching) - #158961 (Reapply "LLVM 23: Run AssignGUIDPass in some places") - #158995 (Use REST API in linkchecker script) - #158996 ([compiler] Implement `PartialOrd` via `Ord` for `Span` and newtype_indexes) - #159036 (bootstrap: expand '@argfile' arguments to rustc shim)

Rollup merge of #158739 - scrabsha:view-types/resolve-fields, r=oli-obk view-types: HIR lowering

JonathanBrouwer · 2026-07-12T07:44:39Z

@rust-timer build 6f0da80

rust-timer · 2026-07-12T11:00:03Z

Finished benchmarking commit (6f0da80): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@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)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	7
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.0%	[-0.1%, -0.0%]	3
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.6%, secondary 0.6%)

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

	mean	range	count
Regressions ❌ (primary)	1.8%	[1.2%, 2.4%]	3
Regressions ❌ (secondary)	2.4%	[1.5%, 4.6%]	9
Improvements ✅ (primary)	-3.1%	[-3.1%, -3.1%]	1
Improvements ✅ (secondary)	-2.2%	[-3.1%, -1.0%]	6
All ❌✅ (primary)	0.6%	[-3.1%, 2.4%]	4

Cycles

Results (secondary -1.0%)

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)	4.5%	[2.2%, 8.6%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.4%	[-9.2%, -1.6%]	9
All ❌✅ (primary)	-	-	0

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 490.768s -> 490.143s (-0.13%)
Artifact size: 389.74 MiB -> 389.19 MiB (-0.14%)

oli-obk · 2026-07-12T11:17:13Z

Just the normal bivariance of the include blob test

JonathanBrouwer · 2026-07-12T20:18:53Z

@rustbot label: +perf-regression-triaged

rustbot assigned oli-obk Jul 3, 2026

scrabsha mentioned this pull request Jul 3, 2026

Tracking Issue for view types #155938

Open

13 tasks

scrabsha changed the title ~~View types/resolve fields~~ view-types: HIR lowering Jul 3, 2026

mejrs reviewed Jul 3, 2026

View reviewed changes

Comment thread compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs Outdated

scrabsha force-pushed the view-types/resolve-fields branch 2 times, most recently from 7d2a7b1 to 9e14883 Compare July 8, 2026 07:52

oli-obk requested changes Jul 8, 2026

View reviewed changes

Comment thread compiler/rustc_hir/src/hir.rs Outdated

Comment thread compiler/rustc_ast_lowering/src/lib.rs

Comment thread compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs Outdated

Comment thread compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

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 Jul 8, 2026

scrabsha added 5 commits July 9, 2026 10:22

view-types: add a bunch of tests

5e4558e

view-types: lower view types to HIR

9ee193e

view-types: error when viewing the same field twice

09b43e4

view-types: error when used on non-struct types

55ab4c7

view-types: resolve viewed fields

1390f89

scrabsha force-pushed the view-types/resolve-fields branch from 9e14883 to 1390f89 Compare July 9, 2026 08:50

rustbot 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 Jul 9, 2026

scrabsha requested a review from oli-obk July 9, 2026 08:55

oli-obk approved these changes Jul 9, 2026

View reviewed changes

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 Jul 9, 2026

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

3c8a057

…, r=oli-obk view-types: HIR lowering

JonathanBrouwer mentioned this pull request Jul 9, 2026

Rollup of 17 pull requests #159007

Closed

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

a06ecb4

…, r=oli-obk view-types: HIR lowering

JonathanBrouwer mentioned this pull request Jul 9, 2026

Rollup of 18 pull requests #159013

Closed

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

9d55c88

…, r=oli-obk view-types: HIR lowering

JonathanBrouwer mentioned this pull request Jul 9, 2026

Rollup of 21 pull requests #159020

Closed

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

5829ca1

…, r=oli-obk view-types: HIR lowering

JonathanBrouwer mentioned this pull request Jul 9, 2026

Rollup of 21 pull requests #159024

Closed

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

602df68

…, r=oli-obk view-types: HIR lowering

JonathanBrouwer mentioned this pull request Jul 9, 2026

Rollup of 24 pull requests #159037

Closed

jhpratt added a commit to jhpratt/rust that referenced this pull request Jul 9, 2026

Rollup merge of rust-lang#158739 - scrabsha:view-types/resolve-fields…

24fe733

…, r=oli-obk view-types: HIR lowering

This was referenced Jul 9, 2026

Rollup of 25 pull requests #159045

Closed

Rollup of 24 pull requests #159046

Merged

rust-bors Bot merged commit 54c75a6 into rust-lang:main Jul 10, 2026
13 checks passed

rustbot added this to the 1.99.0 milestone Jul 10, 2026

scrabsha deleted the view-types/resolve-fields branch July 10, 2026 05:17

rust-timer added a commit that referenced this pull request Jul 10, 2026

Unrolled build for #158739

6f0da80

Rollup merge of #158739 - scrabsha:view-types/resolve-fields, r=oli-obk view-types: HIR lowering

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rustbot added the perf-regression Performance regression. label Jul 12, 2026

rustbot added the perf-regression-triaged The performance regression has been triaged. label Jul 12, 2026

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rust-timer commented Jul 12, 2026

Overall result: ❌✅ regressions and improvements - please read:

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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