@ ProgramNode (location: (1,0)-(7,9))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(7,9))
    └── body: (length: 4)
        ├── @ NextNode (location: (1,0)-(1,4))
        │   ├── arguments: ∅
        │   └── keyword_loc: (1,0)-(1,4) = "next"
        ├── @ NextNode (location: (3,0)-(3,8))
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (3,5)-(3,8))
        │   │   ├── arguments: (length: 1)
        │   │   │   └── @ CallNode (location: (3,5)-(3,8))
        │   │   │       ├── receiver: ∅
        │   │   │       ├── call_operator_loc: ∅
        │   │   │       ├── message_loc: (3,5)-(3,8) = "foo"
        │   │   │       ├── opening_loc: ∅
        │   │   │       ├── arguments: ∅
        │   │   │       ├── closing_loc: ∅
        │   │   │       ├── block: ∅
        │   │   │       ├── flags: variable_call
        │   │   │       └── name: :foo
        │   │   └── flags: ∅
        │   └── keyword_loc: (3,0)-(3,4) = "next"
        ├── @ NextNode (location: (5,0)-(5,6))
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (5,4)-(5,6))
        │   │   ├── arguments: (length: 1)
        │   │   │   └── @ ParenthesesNode (location: (5,4)-(5,6))
        │   │   │       ├── body: ∅
        │   │   │       ├── opening_loc: (5,4)-(5,5) = "("
        │   │   │       └── closing_loc: (5,5)-(5,6) = ")"
        │   │   └── flags: ∅
        │   └── keyword_loc: (5,0)-(5,4) = "next"
        └── @ NextNode (location: (7,0)-(7,9))
            ├── arguments:
            │   @ ArgumentsNode (location: (7,4)-(7,9))
            │   ├── arguments: (length: 1)
            │   │   └── @ ParenthesesNode (location: (7,4)-(7,9))
            │   │       ├── body:
            │   │       │   @ StatementsNode (location: (7,5)-(7,8))
            │   │       │   └── body: (length: 1)
            │   │       │       └── @ CallNode (location: (7,5)-(7,8))
            │   │       │           ├── receiver: ∅
            │   │       │           ├── call_operator_loc: ∅
            │   │       │           ├── message_loc: (7,5)-(7,8) = "foo"
            │   │       │           ├── opening_loc: ∅
            │   │       │           ├── arguments: ∅
            │   │       │           ├── closing_loc: ∅
            │   │       │           ├── block: ∅
            │   │       │           ├── flags: variable_call
            │   │       │           └── name: :foo
            │   │       ├── opening_loc: (7,4)-(7,5) = "("
            │   │       └── closing_loc: (7,8)-(7,9) = ")"
            │   └── flags: ∅
            └── keyword_loc: (7,0)-(7,4) = "next"
