Compilation End diagnostics not displayed correctly

[bjornhellander]

Version Used: Compiled against Roslyn 4.12.0. Running in Visual Studio 17.12.3.

Steps to Reproduce:

I am having problems with an analyzer we are developing, I created a simpler solution from the analyzer template to illustrate the problems, with this analyzer in it:
https://github.com/bjornhellander/CompilationEndAnalyzerProblem1/blob/master/CompilationEndAnalyzerProblem1/CompilationEndAnalyzerProblem1/CompilationEndAnalyzerProblem1Analyzer.cs

If I build the nuget package from this solution and reference it from another project, I expect a warning for each named type symbol.

1. I see the warnings consistently in the Output window.
2. I see the warnings (most of the time?) in the Error List after a complete rebuild.
3. If I build again (just "Build Solution") without making any changes, the warnings are gone from the Error List, regardless of if I select Build Only or e.g. Build + Intellisense.
4. If I instead make a change and build, then I see the warnings from the project being compiled, with warnings from any other projects gone again.
5. I never see the warnings as squigglies in the code.
   I would appreciate any help you can offer on what's going on and if I should do things in another way. This is working really badly for me.

[CyrusNajmabadi]

We don't live run CompilationEnd analyzers in the ide because of the high cost of them. They are only run when you build, and then show up in the "build" section of the error list.

[bjornhellander]

Thanks for the reply!

I buy that you don't live run them. But are the reported diagnostics supposed to disappear in VS after another build? For example points 3 & 4: If I build again and only one project is actually built during that build, all diagnostics for the other projects are in my mind still relevant, but they are no longer displayed in VS. Is that intentional?

And regarding point 5: Are VS squigglies only based on "live" compilation, even for analyzers that are intentionally not run live? Is that why I never see them?