Return reference from TCompactVector::emplace_back

Fixup rXXXXXX
commit_hash:775dffda71dd0a6ad0e91ca361b27ba4f15a0039

2 files changed, 7 insertions, 5 deletions

diff --git a/library/cpp/containers/compact_vector/compact_vector.h b/library/cpp/containers/compact_vector/compact_vector.h
index cff5345ee2..c055bd49da 100644
--- a/library/cpp/containers/compact_vector/compact_vector.h
+++ b/library/cpp/containers/compact_vector/compact_vector.h
@@ -234,15 +234,16 @@ public:
     }
 
     template <class... Args>
-    void EmplaceBack(Args&&... args) {
+    T& EmplaceBack(Args&&... args) {
         Reserve(Size() + 1);
-        new (Ptr + Size()) T(std::forward<Args>(args)...);
+        auto* t = new (Ptr + Size()) T(std::forward<Args>(args)...);
         ++(Header()->Size);
+        return *t;
     }
 
     template <class... Args>
-    void emplace_back(Args&&... args) {
-        EmplaceBack(std::forward<Args>(args)...);
+    T& emplace_back(Args&&... args) {
+        return EmplaceBack(std::forward<Args>(args)...);
     }
 
     T& Back() {
diff --git a/library/cpp/containers/compact_vector/compact_vector_ut.cpp b/library/cpp/containers/compact_vector/compact_vector_ut.cpp
index 5aac5303f3..e576ac3a95 100644
--- a/library/cpp/containers/compact_vector/compact_vector_ut.cpp
+++ b/library/cpp/containers/compact_vector/compact_vector_ut.cpp
@@ -62,7 +62,8 @@ Y_UNIT_TEST_SUITE(TCompactVectorTest) {
         };
 
         TCompactVector<TFoo> vector;
-        vector.emplace_back(123);
+        auto& x = vector.emplace_back(123);
+        UNIT_ASSERT_VALUES_EQUAL(&x, &vector.back());
         UNIT_ASSERT_VALUES_EQUAL(vector.back().ConstructedFrom, "int");
         vector.emplace_back('c');
         UNIT_ASSERT_VALUES_EQUAL(vector.back().ConstructedFrom, "char");