Analyzer

Diagnostic ID: CA1508: Avoid dead conditional code

Analyzer source

NuGet Package: Microsoft.CodeAnalysis.NetAnalyzers

Version: 8.0.0-preview.23364.2 (Latest)

Describe the bug

When variable checked to have one of two values and next checked to have one of those values specifically, CA1508 generated.
For specific code it is possible to workaround (with less code as a bonus) by inverting condition to check value doesn't have remaining possible values.

Steps To Reproduce

public class Test
{
	public static void Method(string parameter)
	{
		var flag = GetFlag();

		// triggers CA1508 below
		if (flag == null || flag == false)
		// workaround: works
		//if (flag != true)
		{
			// CA1508  'flag == false' is always 'false'.Remove or refactor the condition(s) to avoid dead code.
			if (flag == false)
			{
			}
		}
	}

	public static bool? GetFlag() => false;
}

Expected behavior

No errors reported

Actual behavior

Error reported

Additional context