From 56b741627c6d8ecbc5ca5773fcc8d1aa18d27dd4 Mon Sep 17 00:00:00 2001
From: Chayim Refael Friedman <chayimfr@gmail.com>
Date: Fri, 8 May 2026 05:18:48 +0300
Subject: [PATCH] Do not replace closure capture place types with errors if
 they fail to normalize

This prevents panics, and we need to get rid of this normalization anyway, see https://github.com/rust-lang/rust/pull/155767.
---
 crates/hir-ty/src/infer/closure/analysis.rs     | 13 +++++--------
 .../infer/closure/analysis/expr_use_visitor.rs  |  1 -
 crates/hir-ty/src/infer/unify.rs                |  2 +-
 crates/hir-ty/src/tests/closure_captures.rs     | 17 +++++++++++++++++
 4 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/crates/hir-ty/src/infer/closure/analysis.rs b/crates/hir-ty/src/infer/closure/analysis.rs
index 82ace17ac0a7..5ea43bc03ca8 100644
--- a/crates/hir-ty/src/infer/closure/analysis.rs
+++ b/crates/hir-ty/src/infer/closure/analysis.rs
@@ -920,8 +920,8 @@ impl<'a, 'db> InferenceContext<'a, 'db> {
         self.result.closures_data.insert(closure_def_id, closure_data);
     }
 
-    fn normalize_capture_place(&self, span: Span, place: Place) -> Place {
-        let mut place = self.infcx().resolve_vars_if_possible(place);
+    fn normalize_capture_place(&mut self, span: Span, place: Place) -> Place {
+        let place = self.infcx().resolve_vars_if_possible(place);
 
         // In the new solver, types in HIR `Place`s can contain unnormalized aliases,
         // which can ICE later (e.g. when projecting fields for diagnostics).
@@ -945,11 +945,8 @@ impl<'a, 'db> InferenceContext<'a, 'db> {
                 }
                 normalized
             }
-            Err(_errors) => {
-                place.base_ty = self.types.types.error.store();
-                for proj in &mut place.projections {
-                    proj.ty = self.types.types.error.store();
-                }
+            Err(errors) => {
+                self.table.trait_errors.extend(errors);
                 place
             }
         }
@@ -1002,7 +999,7 @@ impl<'a, 'db> InferenceContext<'a, 'db> {
         }
     }
 
-    fn place_for_root_variable(&self, closure_def_id: ExprId, var_hir_id: BindingId) -> Place {
+    fn place_for_root_variable(&mut self, closure_def_id: ExprId, var_hir_id: BindingId) -> Place {
         let place = Place {
             base_ty: self.result.binding_ty(var_hir_id).store(),
             base: PlaceBase::Upvar { closure: closure_def_id, var_id: var_hir_id },
diff --git a/crates/hir-ty/src/infer/closure/analysis/expr_use_visitor.rs b/crates/hir-ty/src/infer/closure/analysis/expr_use_visitor.rs
index f76e99aa7831..deafff6b43e0 100644
--- a/crates/hir-ty/src/infer/closure/analysis/expr_use_visitor.rs
+++ b/crates/hir-ty/src/infer/closure/analysis/expr_use_visitor.rs
@@ -475,7 +475,6 @@ impl<'a, 'b, 'db, D: Delegate<'db>> ExprUseVisitor<'a, 'b, 'db, D> {
         Ok(())
     }
 
-    // FIXME: It's suspicious that this is public; clippy should probably use `walk_expr`.
     #[instrument(skip(self), level = "debug")]
     pub(crate) fn consume_expr(&mut self, expr: ExprId) -> Result {
         let place_with_id = self.cat_expr(expr)?;
diff --git a/crates/hir-ty/src/infer/unify.rs b/crates/hir-ty/src/infer/unify.rs
index 33311412bf25..8527b42d785c 100644
--- a/crates/hir-ty/src/infer/unify.rs
+++ b/crates/hir-ty/src/infer/unify.rs
@@ -134,7 +134,7 @@ pub(crate) struct InferenceTable<'db> {
     pub(crate) infer_ctxt: InferCtxt<'db>,
     pub(super) fulfillment_cx: FulfillmentCtxt<'db>,
     pub(super) diverging_type_vars: FxHashSet<Ty<'db>>,
-    trait_errors: Vec<NextSolverError<'db>>,
+    pub(super) trait_errors: Vec<NextSolverError<'db>>,
 }
 
 impl<'db> InferenceTable<'db> {
diff --git a/crates/hir-ty/src/tests/closure_captures.rs b/crates/hir-ty/src/tests/closure_captures.rs
index b01f44acbc55..d60cf839099f 100644
--- a/crates/hir-ty/src/tests/closure_captures.rs
+++ b/crates/hir-ty/src/tests/closure_captures.rs
@@ -600,3 +600,20 @@ fn f() {
         expect!["77..110;46..47;96..97 ByRef(Immutable) b &'<erased> i32"],
     );
 }
+
+#[test]
+fn fail_to_normalize_place() {
+    check_closure_captures(
+        r#"
+//- minicore: index, slice
+const FAIL_CONST: usize = loop {};
+struct Foo {
+    arr: [i32; FAIL_CONST],
+}
+fn foo(foo: &Foo) {
+    || { return foo.arr[0] };
+}
+    "#,
+        expect!["102..126;85..88;114..117 ByRef(Immutable) *foo &'<erased> Foo"],
+    );
+}