Expression block - Gen<Expr> - 29 - (0:0,0)
    Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        SyntaxKind.Transition;[@];
    Code span - Gen<Expr> - [val?.more(null ?? true)?.abc] - ImplicitExpressionEditHandler;Accepts:NonWhitespace;ImplicitExpression[RTD];K14 - (1:0,1) - Tokens:14
        SyntaxKind.Identifier;[val];
        SyntaxKind.QuestionMark;[?];
        SyntaxKind.Dot;[.];
        SyntaxKind.Identifier;[more];
        SyntaxKind.LeftParenthesis;[(];
        SyntaxKind.Keyword;[null];
        SyntaxKind.Whitespace;[ ];
        SyntaxKind.NullCoalesce;[??];
        SyntaxKind.Whitespace;[ ];
        SyntaxKind.Keyword;[true];
        SyntaxKind.RightParenthesis;[)];
        SyntaxKind.QuestionMark;[?];
        SyntaxKind.Dot;[.];
        SyntaxKind.Identifier;[abc];
