@ ProgramNode (location: (0...11))
├── locals: [:a, :b]
└── statements:
    @ StatementsNode (location: (0...11))
    └── body: (length: 1)
        └── @ LocalVariableWriteNode (location: (0...11))
            ├── name: :a
            ├── depth: 0
            ├── name_loc: (0...1) = "a"
            ├── value:
            │   @ LocalVariableWriteNode (location: (4...11))
            │   ├── name: :b
            │   ├── depth: 0
            │   ├── name_loc: (4...5) = "b"
            │   ├── value:
            │   │   @ CallNode (location: (8...11))
            │   │   ├── receiver: ∅
            │   │   ├── call_operator_loc: ∅
            │   │   ├── message_loc: (8...9) = "c"
            │   │   ├── opening_loc: ∅
            │   │   ├── arguments:
            │   │   │   @ ArgumentsNode (location: (10...11))
            │   │   │   └── arguments: (length: 1)
            │   │   │       └── @ IntegerNode (location: (10...11))
            │   │   │           └── flags: decimal
            │   │   ├── closing_loc: ∅
            │   │   ├── block: ∅
            │   │   ├── flags: ∅
            │   │   └── name: "c"
            │   └── operator_loc: (6...7) = "="
            └── operator_loc: (2...3) = "="
