CA2213 false positive on explicit IAsyncDisposable interface implementation

[wiciok]

Analyzer

Diagnostic ID: CA2213: Disposable fields should be disposed

Analyzer source

SDK: Built-in CA analyzers in .NET 5 SDK or later

Version: 6.0.302

Describe the bug

CA2213 doesn't recognize Dispose / DisposeAsync calls made in explicitly implemented IAsyncDisposable.DisposeAsync method, resulting in false-positive. This happens only when both IAsyncDisposable and IDisposable interfaces are implemented.

Steps To Reproduce

Run analyzers on following code sample:

namespace IAsyncDisposableBug
{
    public sealed class Test : IAsyncDisposable, IDisposable
    {
        private readonly HttpClient client;
        private readonly FileStream stream;

        public Test()
        {
            client = new HttpClient();
            stream = new FileStream("C://some-path", FileMode.CreateNew);
        }

        public void Dispose()
        {
            client.Dispose();
        }

        async ValueTask IAsyncDisposable.DisposeAsync()
        {
            await stream.DisposeAsync();
        }
    }
}

Expected behavior

Dispose/DisposeAsync calls are properly recognized regardless of how DisposeAsync() is implemented

Actual behavior

Dispose/DisposeAsync calls are not properly recognized when made from explicitly implemented IAsyncDisposable.DisposeAsync()

[mavasani]

Interesting, it seems we already have tests for a similar scenario, but it only tests Dispose call within DisposeAsync, not DisposeAsync call within DisposeAsync:

roslyn-analyzers/src/NetAnalyzers/UnitTests/Microsoft.NetCore.Analyzers/Runtime/DisposableFieldsShouldBeDisposedTests.cs

Lines 522 to 552 in bd2c586

	[Fact, WorkItem(3042, "https://github.com/dotnet/roslyn-analyzers/issues/3042")]
	public async Task DisposableAllocationInAsyncDisposableConstructor_AssignedDirectly_Disposed_NoDiagnosticAsync()
	{
	await new VerifyCS.Test
	{
	ReferenceAssemblies = AdditionalMetadataReferences.DefaultWithAsyncInterfaces,
	TestCode = @"
	using System;
	using System.Threading.Tasks;
	class A : IDisposable
	{
	public void Dispose()
	{
	}
	}
	class B : IAsyncDisposable
	{
	private readonly A a;
	public B()
	{
	a = new A();
	}
	public ValueTask DisposeAsync()
	{
	a.Dispose();
	return default(ValueTask);
	}
	}

[mavasani]

#3098 addressed dispose tracking with IAsyncDisposable, but seems it missed out on analyzing await DisposeAsync call within DisposeAsync method.

[mavasani]

This happens only when both IAsyncDisposable and IDisposable interfaces are implemented.

I am wondering if this is another reason for the analysis to break down. Needs investigation.

[wiciok]

It does not matter if it is Dispose, or DisposeAsync that is called from DisposeAsync, it happens in both cases:

This happens only when both IAsyncDisposable and IDisposable interfaces are implemented.

I am wondering if this is another reason for the analysis to break down. Needs investigation.

Yes, IDisposable implementation is definitely required to reproduce this issue. Without it, everything works fine: