1 files changed, 24 insertions, 0 deletions
diff --git a/src/test/ui/return/issue-82612-return-mutable-reference.rs b/src/test/ui/return/issue-82612-return-mutable-reference.rs
new file mode 100644
index 000000000..db0d08ddb
--- /dev/null
+++ b/src/test/ui/return/issue-82612-return-mutable-reference.rs
@@ -0,0 +1,24 @@
+// Regression test for #82612.
+
+use std::marker::PhantomData;
+
+pub trait SparseSetIndex {
+    fn sparse_set_index(&self) -> usize;
+}
+pub struct SparseArray<I, V = I> {
+    values: Vec<Option<V>>,
+    marker: PhantomData<I>,
+}
+
+impl<I: SparseSetIndex, V> SparseArray<I, V> {
+    pub fn get_or_insert_with(&mut self, index: I, func: impl FnOnce() -> V) -> &mut V {
+        let index = index.sparse_set_index();
+        if index < self.values.len() {
+            let value = unsafe { self.values.get_unchecked_mut(index) };
+            value.get_or_insert_with(func) //~ ERROR mismatched types
+        }
+        unsafe { self.values.get_unchecked_mut(index).as_mut().unwrap() }
+    }
+}
+
+fn main() {}