Directive block - Gen<Directive:{custom;SingleLine;Unrestricted}> - 29 - (0:0,0)
    Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        SyntaxKind.Transition;[@];
    MetaCode span - Gen<None> - [custom] - SpanEditHandler;Accepts:None - (1:0,1) - Tokens:1
        SyntaxKind.Identifier;[custom];
    Code span - Gen<None> - [ ] - SpanEditHandler;Accepts:Whitespace - (7:0,7) - Tokens:1
        SyntaxKind.Whitespace;[ ];
    Code span - Gen<DirectiveToken {;Namespace;Opt:False}> - [BaseNamespace.Foo.Bar] - DirectiveTokenEditHandler;Accepts:NonWhitespace - (8:0,8) - Tokens:5
        SyntaxKind.Identifier;[BaseNamespace];
        SyntaxKind.Dot;[.];
        SyntaxKind.Identifier;[Foo];
        SyntaxKind.Dot;[.];
        SyntaxKind.Identifier;[Bar];
