@ ProgramNode (location: (1,0)-(2,3))
├── locals: [:a]
└── statements:
    @ StatementsNode (location: (1,0)-(2,3))
    └── body: (length: 2)
        ├── @ LocalVariableWriteNode (location: (1,0)-(1,6))
        │   ├── name: :a
        │   ├── depth: 0
        │   ├── name_loc: (1,0)-(1,1) = "a"
        │   ├── value:
        │   │   @ IntegerNode (location: (1,4)-(1,6))
        │   │   └── flags: decimal
        │   └── operator_loc: (1,2)-(1,3) = "="
        └── @ CallNode (location: (2,0)-(2,3))
            ├── flags: ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :p
            ├── message_loc: (2,0)-(2,1) = "p"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (2,2)-(2,3))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ LocalVariableReadNode (location: (2,2)-(2,3))
            │           ├── name: :a
            │           └── depth: 0
            ├── closing_loc: ∅
            └── block: ∅
