Expression block - Gen<Expr> - 10 - (0:0,0)
    MetaCode span - Gen<None> - [(] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        CSharpTokenType.LeftParenthesis;[(];
    Code span - Gen<Expr> - [foo barLF] - SpanEditHandler;Accepts:Any - (1:0,1) - Tokens:4
        CSharpTokenType.Identifier;[foo];
        CSharpTokenType.WhiteSpace;[ ];
        CSharpTokenType.Identifier;[bar];
        CSharpTokenType.NewLine;[LF];
