Analyzer

Diagnostic ID: CA2012: Use ValueTasks correctly

Analyzer source

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

Version: SDK 8.0.101

Describe the bug

The following generates CA2012

if (x?.SomeActionReturningValueTaskAsync()) is ValueTask vt)
	await vt;

Steps To Reproduce

Put the following code in any .cs file in Visual Studio

public class Foo
{
	public ValueTask FrobAsync() => default;
	public static async ValueTask FrobFooAsync(Foo? foo)
	{
		if (foo?.FrobAsync() is ValueTask vt)
			await vt;
	}
}

Expected behavior

CA2012 should not be emitted as long as the ValueTask is only consumed once and not otherwise escapes.

Actual behavior

CA2012 is emitted at the "." of foo?.FrobAsync()