refactor the normalization in `coerce_shared_info` by adwinwhite · Pull Request #158659 · rust-lang/rust

adwinwhite · 2026-07-01T13:27:17Z

This is pre-requisite of removing eq_structurally_relating_aliases which is part of #155345.

coerce_shared_info is only used in the unstable feature reborrow which provides a CoerceShared trait indicating a mutable borrow can be converted into a shared borrow.

I think using deeply_normalize is more suitable for these identity instantiated types.
No reason to allow ambiguous normalization and use infer vars as normalization result here.

r? lcnr

lcnr · 2026-07-02T08:16:20Z

-            let ty = f.ty(tcx, args).skip_norm_wip();
-            if ty.is_phantom_data() {
+            let ty = f.ty(tcx, args);
+            if ty.skip_normalization().is_phantom_data() {


can you keep that as skip_norm_wip? I am not confident we don't want to allow <PhantomData as Id>::This here or some free type alias that normalizes to PhantomData

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maybe even a FIXME(whatever-feature)

lcnr · 2026-07-02T08:17:00Z

@@ -0,0 +1,45 @@
+//@ check-pass
+


can you add a comment explaining what this does :>

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lcnr

nits, then r=me

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adwinwhite · 2026-07-03T06:29:12Z

@bors r=lcnr rollup

rust-bors · 2026-07-03T06:29:15Z

📌 Commit 23e6ca0 has been approved by lcnr

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 10. This pull request will be tested once the tree is reopened.

…, r=lcnr refactor the normalization in `coerce_shared_info` This is pre-requisite of removing `eq_structurally_relating_aliases` which is part of rust-lang#155345. `coerce_shared_info` is only used in the unstable feature `reborrow` which provides a `CoerceShared` trait indicating a mutable borrow can be converted into a shared borrow. I think using `deeply_normalize` is more suitable for these identity instantiated types. No reason to allow ambiguous normalization and use infer vars as normalization result here. r? lcnr

Rollup of 18 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #152860 (Port the `without_debuginfo` test from `backtrace-rs` to the testsuite) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #158377 (add `-Zforce-intrinsic-fallback` flag) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

…, r=lcnr refactor the normalization in `coerce_shared_info` This is pre-requisite of removing `eq_structurally_relating_aliases` which is part of rust-lang#155345. `coerce_shared_info` is only used in the unstable feature `reborrow` which provides a `CoerceShared` trait indicating a mutable borrow can be converted into a shared borrow. I think using `deeply_normalize` is more suitable for these identity instantiated types. No reason to allow ambiguous normalization and use infer vars as normalization result here. r? lcnr

…uwer Rollup of 20 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #155989 (Update `transmute_copy` to ub_checks and `?Sized`) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #157857 (Stabilize `#[my_macro] mod foo;` (part of `proc_macro_hygiene`)) - #158377 (add `-Zforce-intrinsic-fallback` flag) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158751 (rustdoc: Fix crash when trying to inline foreign item which cannot have attributes) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

…uwer Rollup of 19 pull requests Successful merges: - #158692 (Add release notes for 1.96.1) - #134021 (Implement `IntoIterator` for `[&[mut]] Box<[T; N], A>`) - #155932 (MIR Call terminator: evaluate destination place before arguments) - #155989 (Update `transmute_copy` to ub_checks and `?Sized`) - #156777 (Add -Zautodiff_post_passes flag to limit which llvm passes to run after enzyme to make autodiff tests more robust) - #157151 (JSON target specs: remove 'x86-softfloat' compatibility alias) - #157835 (expand free alias types in the auto-trait orphan check) - #157857 (Stabilize `#[my_macro] mod foo;` (part of `proc_macro_hygiene`)) - #158434 (delegation: refactor AST -> HIR lowering) - #158552 (make some tidy errors around python easier to understand) - #158624 (borrowck: Introduce BlameConstraint::to_obligation_cause_from_path()) - #158704 (Optimize `ArrayChunks::try_rfold` with `DoubleEndedIterator::next_chunk_back`) - #158711 (library: Comment on libtest's dicey internal soundness) - #158751 (rustdoc: Fix crash when trying to inline foreign item which cannot have attributes) - #158539 (Move `SizeHint` and `IoHandle` to `core::io`) - #158659 (refactor the normalization in `coerce_shared_info`) - #158689 (resolver: don't use `Finalize` when resolving visibilities during AST expansion) - #158698 (Update TypeVisitable implementation) - #158706 (Tweaks to MIR building scope API)

Rollup merge of #158659 - adwinwhite:coerce-shared-info-norm, r=lcnr refactor the normalization in `coerce_shared_info` This is pre-requisite of removing `eq_structurally_relating_aliases` which is part of #155345. `coerce_shared_info` is only used in the unstable feature `reborrow` which provides a `CoerceShared` trait indicating a mutable borrow can be converted into a shared borrow. I think using `deeply_normalize` is more suitable for these identity instantiated types. No reason to allow ambiguous normalization and use infer vars as normalization result here. r? lcnr

rustbot assigned lcnr Jul 1, 2026

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 Jul 1, 2026

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lcnr reviewed Jul 1, 2026

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Comment thread compiler/rustc_hir_analysis/src/coherence/builtin.rs

adwinwhite force-pushed the coerce-shared-info-norm branch 2 times, most recently from e230f7e to 3d7f010 Compare July 2, 2026 06:48

lcnr reviewed Jul 2, 2026

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refactor normalization in coerce_shared_info

23e6ca0

adwinwhite force-pushed the coerce-shared-info-norm branch from 3d7f010 to 23e6ca0 Compare July 3, 2026 03:37

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 3, 2026

jhpratt mentioned this pull request Jul 3, 2026

Rollup of 18 pull requests #158753

Closed

JonathanBrouwer mentioned this pull request Jul 5, 2026

Rollup of 20 pull requests #158798

Closed

JonathanBrouwer mentioned this pull request Jul 5, 2026

Rollup of 19 pull requests #158811

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rust-bors Bot merged commit b820b48 into rust-lang:main Jul 5, 2026
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rustbot added this to the 1.98.0 milestone Jul 5, 2026

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refactor the normalization in `coerce_shared_info`#158659

refactor the normalization in `coerce_shared_info`#158659
rust-bors[bot] merged 1 commit into
rust-lang:mainfrom
adwinwhite:coerce-shared-info-norm

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