@ ProgramNode (location: (0...12))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...12))
    └── body: (length: 1)
        └── @ CallNode (location: (0...12))
            ├── receiver:
            │   @ CallNode (location: (0...1))
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── message_loc: (0...1) = "a"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   ├── block: ∅
            │   ├── flags: variable_call
            │   └── name: "a"
            ├── call_operator_loc: (1...3) = "::"
            ├── message_loc: (3...4) = "b"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (5...8))
            │   └── arguments: (length: 1)
            │       └── @ ParenthesesNode (location: (5...8))
            │           ├── body:
            │           │   @ StatementsNode (location: (6...7))
            │           │   └── body: (length: 1)
            │           │       └── @ IntegerNode (location: (6...7))
            │           │           └── flags: decimal
            │           ├── opening_loc: (5...6) = "("
            │           └── closing_loc: (7...8) = ")"
            ├── closing_loc: ∅
            ├── block:
            │   @ BlockNode (location: (9...12))
            │   ├── locals: []
            │   ├── parameters: ∅
            │   ├── body:
            │   │   @ StatementsNode (location: (10...11))
            │   │   └── body: (length: 1)
            │   │       └── @ CallNode (location: (10...11))
            │   │           ├── receiver: ∅
            │   │           ├── call_operator_loc: ∅
            │   │           ├── message_loc: (10...11) = "c"
            │   │           ├── opening_loc: ∅
            │   │           ├── arguments: ∅
            │   │           ├── closing_loc: ∅
            │   │           ├── block: ∅
            │   │           ├── flags: variable_call
            │   │           └── name: "c"
            │   ├── opening_loc: (9...10) = "{"
            │   └── closing_loc: (11...12) = "}"
            ├── flags: ∅
            └── name: "b"
