From 3a736e2726dcd4cb534eaf64b25196fa45a26a03 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 28 May 2025 12:17:18 +0000
Subject: [PATCH] Handle e2021 precise capturing of unsafe binder

---
 compiler/rustc_middle/src/ty/closure.rs               | 4 ++++
 compiler/rustc_mir_build/src/builder/expr/as_place.rs | 4 ++--
 tests/ui/unsafe-binders/cat-projection.rs             | 3 +++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/closure.rs b/compiler/rustc_middle/src/ty/closure.rs
index ff9096695d4db..df67bb505a689 100644
--- a/compiler/rustc_middle/src/ty/closure.rs
+++ b/compiler/rustc_middle/src/ty/closure.rs
@@ -117,6 +117,10 @@ impl<'tcx> CapturedPlace<'tcx> {
                     }
                 },
 
+                HirProjectionKind::UnwrapUnsafeBinder => {
+                    write!(&mut symbol, "__unwrap").unwrap();
+                }
+
                 // Ignore derefs for now, as they are likely caused by
                 // autoderefs that don't appear in the original code.
                 HirProjectionKind::Deref => {}
diff --git a/compiler/rustc_mir_build/src/builder/expr/as_place.rs b/compiler/rustc_mir_build/src/builder/expr/as_place.rs
index 830a129c58542..f8c64d7d13ed5 100644
--- a/compiler/rustc_mir_build/src/builder/expr/as_place.rs
+++ b/compiler/rustc_mir_build/src/builder/expr/as_place.rs
@@ -101,12 +101,12 @@ fn convert_to_hir_projections_and_truncate_for_capture(
                 variant = Some(*idx);
                 continue;
             }
+            ProjectionElem::UnwrapUnsafeBinder(_) => HirProjectionKind::UnwrapUnsafeBinder,
             // These do not affect anything, they just make sure we know the right type.
             ProjectionElem::OpaqueCast(_) | ProjectionElem::Subtype(..) => continue,
             ProjectionElem::Index(..)
             | ProjectionElem::ConstantIndex { .. }
-            | ProjectionElem::Subslice { .. }
-            | ProjectionElem::UnwrapUnsafeBinder(_) => {
+            | ProjectionElem::Subslice { .. } => {
                 // We don't capture array-access projections.
                 // We can stop here as arrays are captured completely.
                 break;
diff --git a/tests/ui/unsafe-binders/cat-projection.rs b/tests/ui/unsafe-binders/cat-projection.rs
index dd7a78d59b364..0ce8579a68827 100644
--- a/tests/ui/unsafe-binders/cat-projection.rs
+++ b/tests/ui/unsafe-binders/cat-projection.rs
@@ -1,3 +1,6 @@
+//@ revisions: e2015 e2021
+//@[e2015] edition: 2015
+//@[e2021] edition: 2021
 //@ check-pass
 
 #![feature(unsafe_binders)]