Expression block - Gen<Expr> - 3 - (0:0,0)
    Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        CSharpTokenType.Transition;[@];
    MetaCode span - Gen<None> - [(] - SpanEditHandler;Accepts:None - (1:0,1) - Tokens:1
        CSharpTokenType.LeftParenthesis;[(];
    Code span - Gen<Expr> - [] - SpanEditHandler;Accepts:Any - (2:0,2) - Tokens:1
        CSharpTokenType.Unknown;[];
    MetaCode span - Gen<None> - [)] - SpanEditHandler;Accepts:None - (2:0,2) - Tokens:1
        CSharpTokenType.RightParenthesis;[)];
