CSharpCodeBlock - [0..9)::9 - [@val?[-1]]
    CSharpImplicitExpression - [0..9)::9
        CSharpTransition - [0..1)::1 - Gen<None> - SpanEditHandler;Accepts:None
            Transition;[@];
        CSharpImplicitExpressionBody - [1..9)::8
            CSharpCodeBlock - [1..9)::8
                CSharpExpressionLiteral - [1..9)::8 - [val?[-1]] - Gen<Expr> - ImplicitExpressionEditHandler;Accepts:NonWhitespace;ImplicitExpression[RTD];K14
                    Identifier;[val];
                    QuestionMark;[?];
                    LeftBracket;[[];
                    Minus;[-];
                    IntegerLiteral;[1];
                    RightBracket;[]];
