@ ProgramNode (location: (0...12))
├── locals: [:a, :b]
└── statements:
    @ StatementsNode (location: (0...12))
    └── body: (length: 1)
        └── @ MultiWriteNode (location: (0...12))
            ├── targets: (length: 2)
            │   ├── @ LocalVariableTargetNode (location: (1...2))
            │   │   ├── name: :a
            │   │   └── depth: 0
            │   └── @ LocalVariableTargetNode (location: (4...5))
            │       ├── name: :b
            │       └── depth: 0
            ├── lparen_loc: (0...1) = "("
            ├── rparen_loc: (5...6) = ")"
            ├── operator_loc: (7...8) = "="
            └── value:
                @ CallNode (location: (9...12))
                ├── receiver:
                │   @ CallNode (location: (9...10))
                │   ├── receiver: ∅
                │   ├── call_operator_loc: ∅
                │   ├── message_loc: (9...10) = "c"
                │   ├── opening_loc: ∅
                │   ├── arguments: ∅
                │   ├── closing_loc: ∅
                │   ├── block: ∅
                │   ├── flags: variable_call
                │   └── name: "c"
                ├── call_operator_loc: (10...11) = "."
                ├── message_loc: (11...12) = "d"
                ├── opening_loc: ∅
                ├── arguments: ∅
                ├── closing_loc: ∅
                ├── block: ∅
                ├── flags: ∅
                └── name: "d"
