1 files changed, 29 insertions, 0 deletions
diff --git a/absl/container/btree_test.cc b/absl/container/btree_test.cc
index 0c5f9368..43704206 100644
--- a/absl/container/btree_test.cc
+++ b/absl/container/btree_test.cc
@@ -2551,6 +2551,35 @@ TEST(Btree, HeterogeneousInsertOrAssign) {
 }
 #endif
 
+// This test requires std::launder for mutable key access in node handles.
+#if defined(__cpp_lib_launder) && __cpp_lib_launder >= 201606
+TEST(Btree, NodeHandleMutableKeyAccess) {
+  {
+    absl::btree_map<std::string, std::string> map;
+
+    map["key1"] = "mapped";
+
+    auto nh = map.extract(map.begin());
+    nh.key().resize(3);
+    map.insert(std::move(nh));
+
+    EXPECT_THAT(map, ElementsAre(Pair("key", "mapped")));
+  }
+  // Also for multimap.
+  {
+    absl::btree_multimap<std::string, std::string> map;
+
+    map.emplace("key1", "mapped");
+
+    auto nh = map.extract(map.begin());
+    nh.key().resize(3);
+    map.insert(std::move(nh));
+
+    EXPECT_THAT(map, ElementsAre(Pair("key", "mapped")));
+  }
+}
+#endif
+
 }  // namespace
 }  // namespace container_internal
 ABSL_NAMESPACE_END