Error after "prefer IsEmpty over Count" refactoring when original code uses pattern matching syntax

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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[severity:It bothers me. A fix would be nice]
Hi,

in the current version of VS 2026 18.1.0 there seems to be a little bug when trying to apply the “prefer IsEmpty over Count” refactoring on a ConcurrentDictionary. It seems that this is only an issue if the original code uses pattern matching syntax

if (test. Count is > 0) // ... but the refactoring works as expected for: if (test. Count > 0)
  

same for

            if (test. Count is 0)
            {
                test. TryAdd("d", 2);
            }
  

after refactoring its:

            if (IsEmpty)
            {
                test. TryAdd("d", 2);
            }
  

Please see the attached gif video.
Incorrect_IsEmpty_Refactorying.gif

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Original Comments

Feedback Bot on 12/17/2025, 08:50 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

[deepakrathore33]

public static void Main()
{
    System.Collections.Concurrent.ConcurrentDictionary<string, object> test = new ();
    if(test.Count is > 0)
    {
        Console.WriteLine("Dictionary is not empty");
    }
}

[JoeRobich]

Looks like the fixer is https://github.com/dotnet/sdk/blob/main/src/Microsoft.CodeAnalysis.NetAnalyzers/src/Microsoft.CodeAnalysis.NetAnalyzers/Microsoft.NetCore.Analyzers/Performance/PreferIsEmptyOverCount.Fixer.cs