Visual Studio 2017 – Why can’t I see the local and auto variables during UWP app debugging?

I’d like to share my short episode regarding UWP app debugging which happened today. Recent days I’ve developed a WinRT dynamic library which is based on cppwinrt. Most of time, I tested it with an unittest project and everything went fine. However, when I used the WinRT dll from actual .exe UWP application then very strange problem showed up.

As you see the below screenshots, the Visual Studio 2017 debugger shows nothing about local variables, auto and even watch window variables during the UWP app debugging.

Moreover, if I tried to type specific variables into Watch window or immediate window, the debugger shows ‘Internal error in the C# compiler‘ error message!

Later I noticed that the strange problem starts just right after the following output messages come up from Output window.

‘Example.exe’ (CoreCLR: CoreCLR_UWP_Domain): Loaded ‘Anonymously Hosted DynamicMethods Assembly’.

‘Example.exe’ (Win32): Loaded ‘C:\src\Example\build\Win32\Debug\AppX\Example.winmd’. Module was built without symbols.

‘Example.exe’ (CoreCLR: CoreCLR_UWP_Domain): Loaded ‘C:\src\Example\build\Win32\Debug\AppX\Example.winmd’. Module was built without symbols.

How just loading .winmd file could affect the weird debugger problem? Then I realized I used the same name(‘Example’) for the application and the WinRT module both. Which means I created the WinRT dll component as ‘Example.DLL’ and along with ‘Example.winmd’ as its descriptive winmd file name, of course. But I also named the target UWP application as ‘Example’.

So while debugging, the debugger tried to load the winmd file for it’s target WinRT component which was being debugged and suddenly the namespace seemed clashed within between the app and debugee DLL.

So, I changed the name of the WinRT component as ‘Example.Library.dll’ and problem solved!

Thanks,

Heejune

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