@ ProgramNode (location: (0...16))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...16))
    └── body: (length: 1)
        └── @ CallOrWriteNode (location: (0...16))
            ├── 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: ∅
            ├── message_loc: (1...5) = "[:b]"
            ├── opening_loc: (1...2) = "["
            ├── arguments:
            │   @ ArgumentsNode (location: (2...4))
            │   └── arguments: (length: 1)
            │       └── @ SymbolNode (location: (2...4))
            │           ├── opening_loc: (2...3) = ":"
            │           ├── value_loc: (3...4) = "b"
            │           ├── closing_loc: ∅
            │           └── unescaped: "b"
            ├── closing_loc: (4...5) = "]"
            ├── flags: ∅
            ├── read_name: "[]"
            ├── write_name: "[]="
            ├── operator_loc: (6...9) = "||="
            └── value:
                @ CallNode (location: (10...16))
                ├── receiver: ∅
                ├── call_operator_loc: ∅
                ├── message_loc: (10...11) = "c"
                ├── opening_loc: ∅
                ├── arguments:
                │   @ ArgumentsNode (location: (12...16))
                │   └── arguments: (length: 2)
                │       ├── @ IntegerNode (location: (12...13))
                │       │   └── flags: decimal
                │       └── @ IntegerNode (location: (15...16))
                │           └── flags: decimal
                ├── closing_loc: ∅
                ├── block: ∅
                ├── flags: ∅
                └── name: "c"
