Loss of debug info in async methods

Hi,

there seems to be a problem with debug info in async methods: local variables disappear (this is visible in the provided sample) and it seems that the trace (step over from debugger) is also broken (but this is not visible from the sample).

Here is how to reproduce the problem using the attached solution:

• first of all, if you run the debugger on the project DnlibAsync, when you trace into the method named Async(), you can see that the local variable is visible, and correctly set.
• now, run the LoadSaveAssembly project: it will load DnlibAsync.exe and DnlibAsync.pdb from obj directory using dnlib and simply write them to bin.
• when you start the debugger in the project DnlibAsync, now the local variable in Async() method has disappeared (the method works, the generated code has not changed, so this must be the debug info which has changed).

I tried used both symbol loaders (PdbImplType.Managed an PdbImplType.MicrosoftCOM) and get the same result.

Since the example is dumb as hell, I don’t see a point I could have missed in my implementation (which of course, doesn’t mean I 100% sure I made everything right 😎). So, do you think this is a bug?

DnlibAsync.zip

[0xd4d]

@picrap I’ll have a look at it this month, I don’t know how long it will take. There’s a lot of undocumented things, but source code (i.e., Roslyn, Pdb2Xml) exist.

[picrap]

@0xd4d any schedule for this? I am quite stuck with this (and my projects are also impacted).