@ ProgramNode (location: (1,0)-(2,14))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(2,14))
    ├── flags: ∅
    └── body: (length: 2)
        ├── @ UndefNode (location: (1,0)-(1,9))
        │   ├── flags: newline
        │   ├── names: (length: 1)
        │   │   └── @ SymbolNode (location: (1,6)-(1,9))
        │   │       ├── flags: static_literal, forced_us_ascii_encoding
        │   │       ├── opening_loc: ∅
        │   │       ├── value_loc: (1,6)-(1,9) = "foo"
        │   │       ├── closing_loc: ∅
        │   │       └── unescaped: "foo"
        │   └── keyword_loc: (1,0)-(1,5) = "undef"
        └── @ UndefNode (location: (2,0)-(2,14))
            ├── flags: newline
            ├── names: (length: 2)
            │   ├── @ SymbolNode (location: (2,6)-(2,9))
            │   │   ├── flags: static_literal, forced_us_ascii_encoding
            │   │   ├── opening_loc: ∅
            │   │   ├── value_loc: (2,6)-(2,9) = "foo"
            │   │   ├── closing_loc: ∅
            │   │   └── unescaped: "foo"
            │   └── @ SymbolNode (location: (2,11)-(2,14))
            │       ├── flags: static_literal, forced_us_ascii_encoding
            │       ├── opening_loc: ∅
            │       ├── value_loc: (2,11)-(2,14) = "bar"
            │       ├── closing_loc: ∅
            │       └── unescaped: "bar"
            └── keyword_loc: (2,0)-(2,5) = "undef"
