Normalize capture place `ty`s to prevent ICE by JohnTitor · Pull Request #152165 · rust-lang/rust

JohnTitor · 2026-02-05T12:16:16Z

Fixes #151579
Fixes #120811
r? @lcnr

lcnr · 2026-02-08T20:05:09Z

compiler/rustc_middle/src/ty/closure.rs

+        HirPlaceBase::Upvar(upvar_id) => {
+            ty::TypingEnv::post_analysis(tcx, upvar_id.closure_expr_id)
+        }
+        _ => ty::TypingEnv::fully_monomorphized(),


This is hacky and subtly wrong in two ways.

even if the type is not from an upvar, we still need the right param_env to normalize

we use this during MIR build, so it should probably use TypingMode::Borrowck or whatever

see https://rustc-dev-guide.rust-lang.org/typing-parameter-envs.html

Ah I see, I've switched to use try_structurally_resolve_ty as mentioned in the issue: 176bf7d (this PR)
This way, we can avoid deep normalization here, right?

lcnr

ah, I didn't see we always get these types from the typeck_results. We should deeply normalize them in writeback and then assume that they are normalized afterwards

View changes since this review

lcnr · 2026-02-12T11:21:45Z

compiler/rustc_hir_typeck/src/upvar.rs

    }

+    fn try_structurally_resolve_place_ty(&self, span: Span, place: &mut Place<'tcx>) {
+        place.base_ty = self.try_structurally_resolve_type(span, place.base_ty);


use deeply_normalize here. We deeply normalize types in the writeback results, so I think we should do the same here

Just replacing didn't work so I had to do something like this instead: 750cd53

Is this what you meant for?

can you use at.deeply_normalize with both solvers?

I've tried but had to construct TraitEngine there which seems an unusual way (I haven't seen such a way in other places).
Instead, I guess using ObligationCtxt might be better here, other places do this way and it shoudl call at.deeply_normalize internally: a7ea420
How about this?

lcnr · 2026-02-13T13:59:05Z

compiler/rustc_hir_typeck/src/upvar.rs

                    UpvarMigrationInfo::CapturingPrecise {
                        source_expr: capture.info.path_expr_id,
-                        var_name: capture.to_string(self.tcx),
+                        var_name: self.place_to_string_for_migration(capture),


can we move this normalization even further up so that catpure.place is already deeply normalized and we don't have to do so here?

Moved: c22ffdb
I wonder if we should reduce scope by if next_solver as we now normalize stuff more generally, i.e. other than emitting lint rust_2021_incompatible_closure_captures and it would bring unnecessary cost for most cases 🤔

lcnr · 2026-02-14T18:33:02Z

compiler/rustc_hir_typeck/src/upvar.rs

        }
    }

+    fn try_structurally_resolve_place_ty(&self, span: Span, place: &mut Place<'tcx>) {


deeply_normalize should normalize arbitrary TypeFoldable things. Is Place type foldable?

Also, change this function name :>

Ah, you're right, it's TypeFoldable. Addressed: 7def3bc
And I noticed we have another win, it would fix #120811 (N.B. crashes/120911 is a dup of 120811, so I removed it).

lcnr · 2026-02-15T12:30:46Z

I messed up by reviewing your commit directly yesterday, see c22ffdb#r177216090

JohnTitor · 2026-02-16T12:29:33Z

@lcnr Sorry, I missed it 🙏
I think I addressed your comments: ecdea2c
I need to call normalize_capture_place before capture_information.push to prevent ICEs.

compiler/rustc_hir_typeck/src/upvar.rs

rustbot · 2026-02-17T11:32:37Z

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.

JohnTitor · 2026-02-17T11:33:19Z

(rebase mistake, sorry for pinging)

lcnr · 2026-02-26T17:37:31Z

compiler/rustc_hir_typeck/src/upvar.rs

+            let at = self.at(&cause, self.param_env);
+            match solve::deeply_normalize_with_skipped_universes_and_ambiguous_coroutine_goals(
+                at,
+                place.clone(),


i guess to return some place in the error case?

lcnr · 2026-02-26T17:39:09Z

@bors try @rust-timer queue

Normalize capture place `ty`s to prevent ICE

rust-bors · 2026-02-26T19:48:43Z

☀️ Try build successful (CI)
Build commit: 00ebd52 (00ebd52fd0610fe0a77b0caf7ebfb506b3be5e2e, parent: bb779a91568ac1ee0b8a9dcb6b69219ef30b18a3)

rust-timer · 2026-02-26T20:44:08Z

Finished benchmarking commit (00ebd52): comparison URL.

Overall result: no relevant changes - no action needed

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.

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

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	mean	range	count
Regressions ❌ (primary)	3.1%	[3.1%, 3.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.1%	[3.1%, 3.1%]	1

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	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
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Improvements ✅ (secondary)	-3.9%	[-3.9%, -3.9%]	2
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Bootstrap: 480.119s -> 482.867s (0.57%)
Artifact size: 395.65 MiB -> 397.67 MiB (0.51%)

lcnr · 2026-02-27T15:31:29Z

@bors r+ rollup

rust-bors · 2026-02-27T15:31:33Z

📌 Commit dddbf96 has been approved by lcnr

It is now in the queue for this repository.

@lcnr

Normalize capture place `ty`s to prevent ICE Fixes rust-lang#151579 Fixes rust-lang#120811 r? @lcnr

@lcnr

Normalize capture place `ty`s to prevent ICE Fixes rust-lang#151579 Fixes rust-lang#120811 r? @lcnr

…uwer Rollup of 12 pull requests Successful merges: - #153211 (`rust-analyzer` subtree update) - #149027 (Improve cross-crate trait impl param mismatch suggestions ) - #152730 (add field representing types) - #153136 (Correctly handle `#[doc(alias = "...")]` attribute on inlined reexports) - #152165 (Normalize capture place `ty`s to prevent ICE) - #152615 (refactor 'valid for read/write' definition: exclude null) - #153109 (Fix LegacyKeyValueFormat report from docker build: aarch64-gnu-debug) - #153172 (Fix comment about placeholders) - #153187 (Fix ICE when macro-expanded extern crate shadows std) - #153190 (Don't allow subdiagnostic to use variables from their parent) - #153200 (Remove redundant clone) - #153216 (mark two polonius tests as known-bug)

@lcnr

Rollup merge of #152165 - JohnTitor:issue-151579, r=lcnr Normalize capture place `ty`s to prevent ICE Fixes #151579 Fixes #120811 r? @lcnr

rustbot assigned lcnr Feb 5, 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. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Feb 5, 2026

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theemathas mentioned this pull request Feb 6, 2026

ICE : internal error: entered unreachable code #152205

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JohnTitor force-pushed the issue-151579 branch from 88036b0 to 7def3bc Compare February 15, 2026 04:11

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compiler/rustc_hir_typeck/src/upvar.rs Outdated Show resolved Hide resolved

JohnTitor added 4 commits February 17, 2026 20:32

Normalize the whole Place

82b09a1

deeply normalize only on next solver

a4e7e0c

Remove comment about ExprUseVisitor

d79fe52

simplify normalize_capture_place

dddbf96

JohnTitor force-pushed the issue-151579 branch from 5e5de59 to dddbf96 Compare February 17, 2026 11:32

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rust-bors bot pushed a commit that referenced this pull request Feb 26, 2026

Auto merge of #152165 - JohnTitor:issue-151579, r=<try>

00ebd52

Normalize capture place `ty`s to prevent ICE

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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 Feb 27, 2026

JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Feb 28, 2026

Rollup merge of rust-lang#152165 - JohnTitor:issue-151579, r=lcnr

a2f6273

Normalize capture place `ty`s to prevent ICE Fixes rust-lang#151579 Fixes rust-lang#120811 r? @lcnr

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Rollup of 9 pull requests #153208

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JonathanBrouwer added a commit to JonathanBrouwer/rust that referenced this pull request Feb 28, 2026

Rollup merge of rust-lang#152165 - JohnTitor:issue-151579, r=lcnr

42fd093

Normalize capture place `ty`s to prevent ICE Fixes rust-lang#151579 Fixes rust-lang#120811 r? @lcnr

This was referenced Feb 28, 2026

Rollup of 11 pull requests #153212

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Rollup of 12 pull requests #153217

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rust-bors bot merged commit 0381e24 into rust-lang:main Feb 28, 2026
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Unrolled build for #152165

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Rollup merge of #152165 - JohnTitor:issue-151579, r=lcnr Normalize capture place `ty`s to prevent ICE Fixes #151579 Fixes #120811 r? @lcnr

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