IDE0306: Collection initialization can be simplified

[bart-vmware]

This new warning appears during a command-line build and it appears after a full solution build in the VS Error List. After a double-click on the target file, it opens and the warning disappears from the Error List.

Also, the analyzer link https://learn.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/ide0306 returns a 404.

Version Used:
.NET SDK 9.0.200, Visual Studio 2022 v17.12.5

Steps to Reproduce:

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

public class ActuatorMetadataProvider
{
    protected string DefaultContentType { get; }

    public ActuatorMetadataProvider(string defaultContentType)
    {
        ArgumentNullException.ThrowIfNull(defaultContentType);

        DefaultContentType = defaultContentType;
    }

    public virtual EndpointMetadataCollection GetMetadata(string httpMethod)
    {
        ArgumentException.ThrowIfNullOrEmpty(httpMethod);

        List<object> metadata = [];

        if (httpMethod is "DELETE" or "POST" or "PUT" or "PATCH")
        {
            metadata.Add(new ConsumesAttribute(DefaultContentType));
        }

        if (httpMethod != "OPTIONS")
        {
            metadata.Add(new ProducesAttribute(DefaultContentType));
        }

        return new EndpointMetadataCollection(metadata); // <-- warning reported here
    }
}

Full source at: https://github.com/SteeltoeOSS/Steeltoe

I don't understand why a warning is reported, or how to fix it. EndpointMetadataCollection implements IReadOnlyList<object>, IReadOnlyCollection<object> and IEnumerable<object> and has no Add method.

Diagnostic Id:

IDE0306: Collection initialization can be simplified

Expected Behavior:
No warning.

Actual Behavior:
Warning, which disappears after opening the file.

[martincostello]

Similar false positive issue I've encountered myself with Queue<T>.

Given the following code with the .NET 9.0.200 SDK:

class Container(IEnumerable<long> items)
{
    public Queue<long> Items { get; } = new(items);
}

The following diagnostic is emitted:

IDE0306: Collection initialization can be simplified

Applying the code fixer changes the code to:

class Container(IEnumerable<long> items)
{
-   public Queue<long> Items { get; } = new(items);
+   public Queue<long> Items { get; } = [.. items];
}

This then fails to compile with the following error:

CS9215: Collection expression type 'Queue<long>' must have an instance or extension method 'Add' that can be called with a single argument.

[CyrusNajmabadi]

Dupe of #76683