CoreLib's coverage measurement is broken

After figuring out why CoreLib doesn’t write the result file when being instrumented by coverlet and working around the issue, I noticed that the WriteLog and WriteHits methods in the ModuleTrackerTemplate throw:

  Unhandled exception. System.TypeLoadException: Could not load type 'System.Diagnostics.Process' from assembly 'System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'.
     at Coverlet.Core.Instrumentation.Tracker.System.Private.CoreLib_19e73ecb-b988-441a-913d-54373b41abc8.WriteLog(String)
     at Coverlet.Core.Instrumentation.Tracker.System.Private.CoreLib_19e73ecb-b988-441a-913d-54373b41abc8.UnloadModule(Object, EventArgs)
     at System.AppContext.OnProcessExit() in C:\git\runtime3\src\libraries\System.Private.CoreLib\src\System\AppContext.cs:line 88

• https://github.com/coverlet-coverage/coverlet/blob/df968b862687aeb9ac86ae47938da04d95c10452/src/coverlet.core/Instrumentation/ModuleTrackerTemplate.cs#L176
• https://github.com/coverlet-coverage/coverlet/blob/df968b862687aeb9ac86ae47938da04d95c10452/src/coverlet.core/Instrumentation/ModuleTrackerTemplate.cs#L200

That’s because CoreLib doesn’t have access to the Process type and even though those code paths aren’t running by default, they are in the IL and hence the types are tried to be resolved. To unblock dotnet/runtime it would be great if these code paths that rely on Process could be changed to not include the process id.

cc @stephentoub

[stephentoub]

Thank you for working on the fixes, @MarcoRossignoli.

[MarcoRossignoli]

We’ll ship nightly build at midnight, would be great is someone tomorrow give it a try to check if this first issue is solved https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/ConsumeNightlyBuild.md