Debugger visualizers in Visual Sudio 11 Developer Preview

Visual Studio 11 Developer Preview introduces new style debugger visualizers. The autoexp.dat definition of templates in previous versions of the Visual Studio debugger is being replaced with new style definitions based on XML and stored in defaultvis.natvis file.

Microsoft explains the motivation behind redesigning the native type visualization mechanism is to give better diagnostic reporting (visualizer expressions can be now evaluated and displayed in the output window to help debugging .natvis file), provide XSD schema defining type definition, support of multiple files for type definition: system-wide in %ProgramFiles%\Microsoft Visual Studio 11.0\Common7\Packages\Debugger\Visualizers\defaultvis.natvis and user-defined in %USERPROFILE%\My Documents\Visual Studio Dev11\Visualizers\xxx.natvis.

It sounds really good and has a great usability potential for programmers who uses C++ generative programming capabilities, defines complex C++ types, heavily uses C++ Standard Library and Boost C++ Libraries.

Here is example of new style visualizer defined in XML copied from the defaultvis.natvis:

  <!--std::unique_ptr from <memory>-->
  <Type Name="std::unique_ptr<*>">
    <DisplayString Condition="_Myptr == 0">empty</DisplayString>
    <DisplayString>unique_ptr {*_Myptr}</DisplayString>
    <Expand>
      <Item Name="[ptr]" Condition="_Myptr != 0">_Myptr</Item>
    </Expand>
  </Type>

For most types from C++ Standard Library and Windows SDK, the new visualizers work very well. However, the currently available Visual Studio 11 Developer Preview (Version 11.0.40825.2 PREREL) is shipped with incorrect definitions in the defaultvis.natvis. The C++TR1 definitions introduced in Visual Studio 2008 are only forwarded (aliased) from std:tr1:: to std:: in Visual Studio 2010. In Visual Studio 11, they have completely moved from std::tr1:: to std:: to align with C++11 standard. But, the new visualizers in defaultvis.natvis define templates are still referring to the C++11 types in std::tr1:: namespace.

This prevents the correct visualization for types like std::shared_ptr:

There is an easy workaround possible:

1. Make private copy of defaultvis.natvis in %USERPROFILE%\My Documents\Visual Studio Dev11\Visualizers\xxx.natvis where xxx is your preferred name.

2. Open xxx.natvis in a text editor.

3. Find std::tr1:: and replace with std::.

4. Save the changes and relaunch the Visual Studio 11.

5. You should see objects of the C++11 types correctly visualized.

I have reported this issue to Microsoft Connect in Incorrect Type Name references in defaultvis.natvis visualizers for standard library ticket.