@ ProgramNode (location: (1,0)-(3,3))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(3,3))
    └── body: (length: 1)
        └── @ ClassNode (location: (1,0)-(3,3))
            ├── locals: []
            ├── class_keyword_loc: (1,0)-(1,5) = "class"
            ├── constant_path:
            │   @ ConstantReadNode (location: (1,6)-(1,7))
            │   └── name: :X
            ├── inheritance_operator_loc: ∅
            ├── superclass: ∅
            ├── body:
            │   @ StatementsNode (location: (2,2)-(2,21))
            │   └── body: (length: 1)
            │       └── @ DefNode (location: (2,2)-(2,21))
            │           ├── name: :==
            │           ├── name_loc: (2,11)-(2,13) = "=="
            │           ├── receiver:
            │           │   @ SelfNode (location: (2,6)-(2,10))
            │           ├── parameters:
            │           │   @ ParametersNode (location: (2,14)-(2,15))
            │           │   ├── requireds: (length: 1)
            │           │   │   └── @ RequiredParameterNode (location: (2,14)-(2,15))
            │           │   │       └── name: :o
            │           │   ├── optionals: (length: 0)
            │           │   ├── rest: ∅
            │           │   ├── posts: (length: 0)
            │           │   ├── keywords: (length: 0)
            │           │   ├── keyword_rest: ∅
            │           │   └── block: ∅
            │           ├── body:
            │           │   @ StatementsNode (location: (2,19)-(2,21))
            │           │   └── body: (length: 1)
            │           │       └── @ IntegerNode (location: (2,19)-(2,21))
            │           │           └── flags: decimal
            │           ├── locals: [:o]
            │           ├── locals_body_index: 1
            │           ├── def_keyword_loc: (2,2)-(2,5) = "def"
            │           ├── operator_loc: (2,10)-(2,11) = "."
            │           ├── lparen_loc: (2,13)-(2,14) = "("
            │           ├── rparen_loc: (2,15)-(2,16) = ")"
            │           ├── equal_loc: (2,17)-(2,18) = "="
            │           └── end_keyword_loc: ∅
            ├── end_keyword_loc: (3,0)-(3,3) = "end"
            └── name: :X
