<string>: ASan annotations do not prevent writing to allocated but uninitialized `basic_string` memory

[davidmrdavid]

Describe the bug

ASan does not fire when writing to uninitialized memory in a basic_string, unlike with vector.

Command-line test case

C:\Temp>type repro.cpp
#include <vector>
#include <string>

int main()
{
    // This crashes (expectedly)
    //std::vector<int> vec;
    //vec.reserve(100);
    //vec.data()[50] = 1;

    // This does not crash (it should crash, like `vector`)
    std::basic_string<char> myString;
    myString.reserve(100);
    char* data = &myString[0];
    data[50] = 'A';

}

C:\Temp>cl /EHsc /Zi /fsanitize=address .\repro.cpp

Microsoft (R) C/C++ Optimizing Compiler Version 19.43.34618 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

repro.cpp
Microsoft (R) Incremental Linker Version 14.43.34618.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:repro.exe
/debug
/InferAsanLibs
repro.obj

C:\Temp>.\repro.exe
<no ASan failure thrown>

Expected behavior

ASan should throw a container-overflow-type error due to a WRITE on an uninitialized section of container memory.

STL version

Microsoft Visual Studio Enterprise 2022
Version 17.13.0 Preview 2.1

Additional context

This bug was discovered while developing the basic_string test case for #5241, and has already been discussed internally.