When was the binding property pattern { } introduced?

[The-Futurist]

As in:

if (await datasetsRepository.GetUserData(userId) is { } userFromDatabase)
{
    retrievedUsers.TryAdd(userId, userFromDatabase);
    return true;
}

[333fred]

It's the empty property pattern. There's no real reason to add a specific error for using it.

[jnm2]

C# version 8.0. This feature was called recursive patterns but as more recursive patterns were added later, is now called the property pattern.

[The-Futurist]

Fascinating I never noticed it before even though I scoured the docs back then.