Visual C++ 2013 std::string memory leak - c++

Question

During development of proprietary app. I have noticed memory leak, related to std::string in a MS Visual C++ 2013, Update 4.
Take a look at the following (basic) code prototype which causes memory leak:
static std::string MemoryLeakTest()
{
static size_t const test_size = 2002;
std::unique_ptr<char[]> result1(new char[test_size]);
std::string result2(result1.get(), test_size);
return result2;
}
calling it by:
std::string const testML = MemoryLeakTest();
std::cout << testML << std::endl;
Am I doing something wrong, or is it a memory leak in a Visual C++ STL?
P.S. this is DebugView output showing mem leak detected by VLD:
[11140] WARNING: Visual Leak Detector detected memory leaks!
[11140] ---------- Block 3 at 0x00A95620: 2002 bytes ----------
[11140] Leak Hash: 0x1DA884B6, Count: 1, Total 2002 bytes
[11140] Call Stack (TID 9568):
[11140] 0x0FF5C260 (File and line number not available): MSVCR120D.dll!operator new
[11140] f:\dd\vctools\crt\crtw32\stdcpp\newaop.cpp (6): TestCpp.exe!operator new[] + 0x9 bytes
[11140] c:\work\testcpp\testcpp.cpp (307): TestCpp.exe!MemoryLeakTest + 0xA bytes
[11140] c:\work\testcpp\testcpp.cpp (401): TestCpp.exe!wmain + 0x9 bytes
[11140] f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c (623): TestCpp.exe!__tmainCRTStartup + 0x19 bytes
[11140] f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c (466): TestCpp.exe!wmainCRTStartup
[11140] 0x75557C04 (File and line number not available): KERNEL32.DLL!BaseThreadInitThunk + 0x24 bytes
[11140] 0x77C4B54F (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0x8F bytes
[11140] 0x77C4B51A (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0x5A bytes
[11140] Data:

Answer 1

Tried your code with Deleaker and it couldn't find any leak.
Then tried this code:
while (true)
{
std::string const testML = MemoryLeakTest();
std::cout << testML << std::endl;
}
Task Manager shows that memory usage remains the same: no leaks.
I think this is a bug in VLD, you can find that std::unique_ptr really frees the memory, just step into during debugging, look:
~unique_ptr() _NOEXCEPT
{ // destroy the object
_Delete();
}
Go further:
void _Delete()
{ // delete the pointer
if (this->_Myptr != pointer())
this->get_deleter()(this->_Myptr);
}
};
Go further:
void operator()(_Ty *_Ptr) const _NOEXCEPT
{ // delete a pointer
static_assert(0 < sizeof (_Ty),
"can't delete an incomplete type");
delete[] _Ptr;
}
};
Aha, delete[] is called!

Answer 2

The call
std::unique_ptr<char[]> result1(new char[test_size]);
is correct. The tricky part is NOT to write std::unique_ptr<char>, which also compiles and can cause a memory leak (unique_ptr calls delete to release resource. When initialized with new[], we need to instruct unique_ptr to call the correct delete[]).
The std::string constructor call is also OK and it's very unlikely there's a memory leak. The std::string can be initialized from a C-style pointer in the same way.
I don't see any memory leak in your code snippet. How do you know it's a memory leak?