[TestCaseSource] CA1812 suppression #999

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1. manfred-brands commented on Jun 26, 2026

   

   manfred-brands

   on Jun 26, 2026

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   @uladz-zubrycki Could you add an minimal example please?

   Are you using nameof(source) for the TestCaseSource. That would be a usage of the member which then should be a usage of the type.
2. uladz-zubrycki commented on Jun 26, 2026

   

   uladz-zubrycki

   on Jun 26, 2026

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   @manfred-brands, Sure.

   dotnet_diagnostic.CA1812.severity = warning
   

   <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   

   internal sealed class FooSource: IEnumerable
   {
   	public IEnumerator GetEnumerator() => throw new NotImplementedException();
   }
   
   [TestFixture]
   internal sealed class FooFixture
   {
   	[TestCaseSource(typeof(FooSource))]
   	public void Foo() { }
   }
   

   Produces

   Error CA1812 : 'FooSource' is an internal class that is apparently never instantiated. If so, remove the code from the assembly. If this class is intended to contain only static members, make it 'static' (Module in Visual Basic). (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1812)
   

   That would be a usage of the member which then should be a usage of the type.

   CA1812 is detecting types that are never instantiated, not unused types.
3. manfred-brands commented on Jul 3, 2026

   

   manfred-brands

   on Jul 3, 2026

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   @uladz-zubrycki This one is problematic.

   The analyzer reports the 'uninstantiated' class at its declaration location, which could be in a different file all together.
   It could be referenced multiple times anywhere.

   I have found one way where I search all sources that are part of the compilation for the text: Source(typeof(XXX) where XXX is the class reported to be uninstantiated.
   This detects all 3 NUnit attributes: TestCaseSource, ValueSource and TestFixtureSource.

   👍React with 👍1Reacted by Uladz Zubrycki
4. manfred-brands

   closed this as completedin #1012on Sep 10, 2026
5. mikkelbu

   added this to the Release 4.15 milestone on Sep 12, 2026