Custom matcher properties not printed correctly in error messages

[stakx]

Consider this test code:

public interface IChild
{
    void PlayWith(Toy toy);
}

public class Toy
{
    public string Color { get; set; }

    public static Toy ThatIsRed => Match.Create((Toy toy) => toy.Color == "red");
}

[Fact] // does not pass
public void Custom_matcher_property_appears_by_name_in_verification_error_message()
{
    var child = new Mock<IChild>();
    child.Setup(c => c.PlayWith(Toy.ThatIsRed)).Verifiable();

    var ex = Assert.Throws<MockException>(() => child.Verify());

    Assert.Contains(".PlayWith(Toy.ThatIsRed)", ex.Message);
}

The test fails with:

Message: Assert.Contains() Failure
Not found: .PlayWith(Toy.ThatIsRed)
In value:  The following setups were not matched:
IChild c => c.PlayWith(null)

The error message contains "null" instead of the matcher property's name.