CA1861 false positive in method attribute

[koenigst]

Analyzer

Diagnostic ID: CA1861: Avoid constant arrays as arguments

Analyzer source

Version: SDK 8.0.100

Describe the bug

A constant array in an attribute initializer produces diagnostic CA1861 but extracting the array into a static field is not possible due to language constraints.

Steps To Reproduce

1. Enable all analyzers.

    <EnableNETAnalyzers>true</EnableNETAnalyzers>
    <AnalysisMode>All</AnalysisMode>

2. Add attribute with array.

public class Test
{
    [Xunit.Theory]
    [Xunit.InlineData("a", new[] { "b" })]
    public void Method(string a, string[] b) { }
}

Expected Behavior:
The array new[] { "b" } has no compiler warnings.

Actual Behavior:
The array new[] { "b" } has a CA1861 warning but the code cannot be changed because no field is allowed in attribute syntax.

[JeppeSN]

Happens for other attributes, like NUnit.Framework.TestCaseAttribute where it would be:

[TestCase("a", new[] { "b" })]   // false CA1861

A hillarious workaround is to write:

[Xunit.InlineData("a", (string[])["b"])]

where the cast (string[]) is needed only if the attribute class constructor in question takes a very general argument, like object. If the receiver already wants a concrete array, ["b"] without cast is sufficient.

[DoctorKrolic]

@mavasani How roslyn analyzers are updated for users? Are they bound to version of VS or .NET SDK or what? This issue if fixed sor quite some time, but I still have this bug (VS 17.9P5, latest .NET 8 SDK). Very annoying...