What happens if we declare [Flags] enum in order?

Question

I have came across this question: What does the [Flags] Enum Attribute mean in C#?

And one thing I have been wondering, using the accepted answer's example, what will happen if I declare:

[Flags]
public enum MyColors
{
    Yellow = 1,
    Green = 2,
    Red = 3,
    Blue = 4
}

Will the following steps in that example resulting an error? If no, how can I get to MyColors.Red?

Answer 1

It will result in unexpected results. Common practice to make uniqueness is just to mark enum values with power of 2.

For instance Yellow bitwise or Green will result in Red and so on.

MyColors colors = MyColors.Yellow | MyColors.Green;
if (colors == MyColors.Red)
{
    Console.WriteLine("Oops!")
}

Also note Flags attribute does nothing here, it gives the impression that you can use bitwise or.