I have the following correct code.

abstract class T
{
    protected abstract int Q { get; }
}
class T1 : T
{
    protected override int Q
    {
        get { throw new System.NotImplementedException(); }
    }
}

Now I type

set { }

to the second property. The error is underlined with BLUE. As soon as I change the text inside setter (even if I undo the changes afterwards) the error highlighting has regular red color.

Issue was closed