@ ProgramNode (location: (1,0)-(1,9))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,9))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ InstanceVariableWriteNode (location: (1,0)-(1,9))
            ├── flags: newline
            ├── name: :@var
            ├── name_loc: (1,0)-(1,4) = "@var"
            ├── value:
            │   @ IntegerNode (location: (1,7)-(1,9))
            │   ├── flags: static_literal, decimal
            │   └── value: 10
            └── operator_loc: (1,5)-(1,6) = "="
