@ ProgramNode (location: (0...38))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...38))
    └── body: (length: 4)
        ├── @ SourceEncodingNode (location: (0...12))
        ├── @ SourceFileNode (location: (13...21))
        │   └── filepath: "unparser/corpus/literal/pragma.txt"
        ├── @ SourceLineNode (location: (22...30))
        └── @ CallNode (location: (31...38))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (31...38) = "__dir__"
            ├── opening_loc: ∅
            ├── arguments: ∅
            ├── closing_loc: ∅
            ├── block: ∅
            ├── flags: variable_call
            └── name: "__dir__"
