From 6eb6ff62f78560720f6902421dcd482cb70482ed Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <spastorino@gmail.com>
Date: Fri, 14 Feb 2025 18:35:43 -0300
Subject: [PATCH] Allow to mutate use captures

---
 compiler/rustc_borrowck/src/lib.rs            | 20 ++++++++++++-------
 tests/ui/ergonomic-clones/closure/mutation.rs | 11 ++++++++++
 2 files changed, 24 insertions(+), 7 deletions(-)
 create mode 100644 tests/ui/ergonomic-clones/closure/mutation.rs

diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 68e0ab0933e6..64a533e05ffd 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -1490,14 +1490,20 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, '_, 'tcx> {
                         let stmt = &bbd.statements[loc.statement_index];
                         debug!("temporary assigned in: stmt={:?}", stmt);
 
-                        if let StatementKind::Assign(box (_, Rvalue::Ref(_, _, source))) = stmt.kind
-                        {
-                            propagate_closure_used_mut_place(self, source);
-                        } else {
-                            bug!(
-                                "closures should only capture user variables \
+                        match stmt.kind {
+                            StatementKind::Assign(box (
+                                _,
+                                Rvalue::Ref(_, _, source)
+                                | Rvalue::Use(Operand::Copy(source) | Operand::Move(source)),
+                            )) => {
+                                propagate_closure_used_mut_place(self, source);
+                            }
+                            _ => {
+                                bug!(
+                                    "closures should only capture user variables \
                                  or references to user variables"
-                            );
+                                );
+                            }
                         }
                     }
                     _ => propagate_closure_used_mut_place(self, place),
diff --git a/tests/ui/ergonomic-clones/closure/mutation.rs b/tests/ui/ergonomic-clones/closure/mutation.rs
new file mode 100644
index 000000000000..2e2f0dddf80a
--- /dev/null
+++ b/tests/ui/ergonomic-clones/closure/mutation.rs
@@ -0,0 +1,11 @@
+//@ check-pass
+
+#![feature(ergonomic_clones)]
+
+fn main() {
+    let mut my_var = false;
+    let mut callback = use || {
+        my_var = true;
+    };
+    callback();
+}