Roslyn: CS8019 doesn't work during compilation

[davidrea-MS]

Version Used: VS 2017 15.3.5

Steps to Reproduce:

1. Create new Class Library (.NET Framework) project.
2. Edit Active Rule Set and make CS8019 (Unnecessary using directive) an 'Error'.
3. Compile project.

Expected Behavior:
Given that the project starts with a Class1.cs file containing unused using directives, compilation should fail.

Actual Behavior:
Compilation succeeds. The VS UI does show the IntelliSense error, however.

Attached repro project.
AnalyzerTest.zip

[jcouv]

Confirmed. Working on a fix.
This warning is reported separately from the other ones and wasn't undergoing the filtering that applies the diagnostic options.

Note to self: branch ruleset-bug

[jcouv]

From discussion with @sharwell this should be handled in the IDE layer rather than the compiler layer, as this diagnostic is more of a code style. Thanks

[sharwell]

Closing in favor of #28773

[mkamoski]

This is still a bug in Visual Studio 2019 16.4.2 as of now.

[sharwell]

@mkamoski I am not aware of a bug currently in this space. If you are experiencing an issue with this diagnostic, can you file a new issue with the details so we can investigate it?

[yohny]

I'm still experiencing this issue too (exactly as described in original bug report), VS2019 16.4.3
The CS8019 error is reported by IntelliSense, yet the build finishes without error.

[sharwell]

@yohny can you file a new issue so we can investigate?

[msallin]

Here we go: https://github.com/dotnet/roslyn/issues/41391