Don't get offered usings/spell checker etc inside the method body of an abstract method

Was doing refactoring where I wanted to convert an abstract method -> virtual method, I added a body to the abstract method and while I got normal intellisense, I did not offered usings or spelling check code actions, etc until I removed the "abstract".

This feels strange to be me, because other invalid constructs such as unrecognized modifiers don't stop me from getting offered these.

    class Program
    {
        internal abstract void Method()
        {
            String foo; 
        }
    }

1. CTRL+. on String

Expected: To get offered to add "using System;" Actual: Nothing.