Fix #3031: emit sequence points for expression-bodied properties and indexers

[KirillOsenkov]

Need to visit properties and indexers in SequencePointBuilder to account for ExpressionBody.

Adds a failing test for all kinds of members. Currently failing with an unrelated duplicate sequence points for a local function body.

[siegfriedpammer]

Thank you for the proposed fix. If I remember correctly, SequencePointBuilder should only handle statements and expressions, so everything inside a method, ctor, property, indexer, etc. The correct place to fix this would be DebugInfoGenerator which maps the generated sequence points to MethodDefinitions in the assembly. See my proposed fix in https://github.com/icsharpcode/ILSpy/tree/pdbgen-fixes...

There is one more nut I need to crack regarding local functions, but I might be able to get to that this week.

Note that we intentionally do not use expression-bodied members for single accessors, but only for getter-only properties/indexers. Also note that my branch mentioned above fixes another issue in the getter-only transform.

Thanks for creating a test case. I hope we'll be able to solve the PDB gen unit testing problem soon!

[siegfriedpammer]

I think I will be basing the fix on the changes in my branch and use as much as possible from this PR. There is no need for you to invest any more time. However, I would very grateful, if you could take my final solution for a test ride. Thank you very much!

[siegfriedpammer]

Thank you for the proposed fix. If I remember correctly, SequencePointBuilder should only handle statements and expressions, so everything inside a method, ctor, property, indexer, etc. The correct place to fix this would be DebugInfoGenerator which maps the generated sequence points to MethodDefinitions in the assembly. See my proposed fix in pdbgen-fixes...

I have to retract this previous statement: the changes to SequencePointBuilder are equally necessary. Sorry for the confusion on my end. :) It's been a long time since I touched that part of the decompiler...

[siegfriedpammer]

@KirillOsenkov I have pushed my changes. I have cleaned up the PR a bit. Could you try and test the generated PDB on your end? It seems to work fine with VS 17.6.4. Thanks a lot!

[KirillOsenkov]

Sorry, I should have clarified, I don't work on the Visual Studio debugger team and I am not using the pdb generation logic at all. I'm not using the DebugInfoGenerator for my purposes, I only use the SequencePointBuilder to get the raw sequence points. The changes in my PR are sufficient for my needs, however the VS debugger team is likely to need both your and my changes (I'm guessing).

[KirillOsenkov]

Other than the potential duplicate ILFunction annotations in CopyAnnotationsFrom, it looks good as far as I can see. Thanks!

[KirillOsenkov]

Looks great as far as I can see. Thanks so much! 👍🏻

[siegfriedpammer]

Thank you for your help with this!