EventKeywords enum in checked-in netstandard.dll/2.0.3 IL source is missing long base type

[mthalman]

When running GenAPI on NuGet.Common.6.8.1, it produces the following snippet in the NuGetEventSource.Keywords nested class:

public const System.Diagnostics.Tracing.EventKeywords Common = 1L;
public const System.Diagnostics.Tracing.EventKeywords Configuration = 2L;
public const System.Diagnostics.Tracing.EventKeywords Logging = 4L;
public const System.Diagnostics.Tracing.EventKeywords Performance = 8L;
public const System.Diagnostics.Tracing.EventKeywords SdkResolver = 16L;

This fails to compile:

error CS0266: Cannot implicitly convert type 'long' to 'System.Diagnostics.Tracing.EventKeywords'. An explicit conversion exists (are you missing a cast?)

This is fixed by explicitly casting to the enum type:

public const System.Diagnostics.Tracing.EventKeywords Common = (System.Diagnostics.Tracing.EventKeywords)1L;
public const System.Diagnostics.Tracing.EventKeywords Configuration =(System.Diagnostics.Tracing.EventKeywords) 2L;
public const System.Diagnostics.Tracing.EventKeywords Logging = (System.Diagnostics.Tracing.EventKeywords)4L;
public const System.Diagnostics.Tracing.EventKeywords Performance = (System.Diagnostics.Tracing.EventKeywords)8L;
public const System.Diagnostics.Tracing.EventKeywords SdkResolver = (System.Diagnostics.Tracing.EventKeywords)16L;

See dotnet/source-build-reference-packages@008bdd5 from dotnet/source-build-reference-packages#896 for an example of this occurrence.

[ViktorHofer]

@mthalman this isn't related to GenAPI but to the checked-in IL source in SBRP.

Here's the source code in netstandard.dll/2.0.3 for the EventKeywords enum: https://github.com/dotnet/standard/blob/908070fe0491d2b20761c32ebc375829c6c8c0cf/src/netstandard/ref/System.Diagnostics.Tracing.cs#L104

When you look at the checked-in IL source in SBRP, you can see that the enum is missing the long base type: https://github.com/dotnet/source-build-reference-packages/blob/main/src/targetPacks/ILsrc/netstandard.library/2.0.3/build/netstandard2.0/ref/netstandard.il -> L333394

Would you know how that IL source got generated? ILDasm? Moving this issue to source-build.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[MichaelSimons]

It was generated by some internal tooling located here(Microsoft internal link) The tooling is ildasm based. The current version of the tooling may be newer than this was originally generated from. I would first try regenerating to see if the problem is resolved. Also make sure the latest ildasm is used as noted in the readme

[MichaelSimons]

FWIW, I regenerated netstandard.library 2.0.3 with the 9.0.0 IlDasm and the resulting IL didn't change. Possibly another reason to invest in using GenAPI on the targeting packs.