Expression block - Gen<Expr> - 12 - (0:0,0)
    Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        CSharpTokenType.Transition;[@];
    Code span - Gen<Expr> - [foo.bar.baz] - ImplicitExpressionEditHandler;Accepts:NonWhiteSpace;ImplicitExpression[RTD];K14 - (1:0,1) - Tokens:5
        CSharpTokenType.Identifier;[foo];
        CSharpTokenType.Dot;[.];
        CSharpTokenType.Identifier;[bar];
        CSharpTokenType.Dot;[.];
        CSharpTokenType.Identifier;[baz];
