@ ProgramNode (location: (0...8))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...8))
    └── body: (length: 1)
        └── @ CallNode (location: (0...8))
            ├── 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: (7...8))
            │   └── arguments: (length: 1)
            │       └── @ IntegerNode (location: (7...8))
            │           └── flags: decimal
            ├── closing_loc: ∅
            ├── block: ∅
            ├── flags: safe_navigation
            └── name: "b="
