@ ProgramNode (location: (1,0)-(9,25))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(9,25))
    └── body: (length: 5)
        ├── @ ConstantPathOperatorWriteNode (location: (1,0)-(1,8))
        │   ├── target:
        │   │   @ ConstantPathNode (location: (1,0)-(1,3))
        │   │   ├── parent: ∅
        │   │   ├── child:
        │   │   │   @ ConstantReadNode (location: (1,2)-(1,3))
        │   │   │   └── name: :A
        │   │   └── delimiter_loc: (1,0)-(1,2) = "::"
        │   ├── operator_loc: (1,4)-(1,6) = "+="
        │   ├── value:
        │   │   @ IntegerNode (location: (1,7)-(1,8))
        │   │   ├── flags: decimal
        │   │   └── value: 1
        │   └── operator: :+
        ├── @ ConstantOperatorWriteNode (location: (3,0)-(3,6))
        │   ├── name: :A
        │   ├── name_loc: (3,0)-(3,1) = "A"
        │   ├── operator_loc: (3,2)-(3,4) = "+="
        │   ├── value:
        │   │   @ IntegerNode (location: (3,5)-(3,6))
        │   │   ├── flags: decimal
        │   │   └── value: 1
        │   └── operator: :+
        ├── @ ConstantPathOperatorWriteNode (location: (5,0)-(5,9))
        │   ├── target:
        │   │   @ ConstantPathNode (location: (5,0)-(5,4))
        │   │   ├── parent:
        │   │   │   @ ConstantReadNode (location: (5,0)-(5,1))
        │   │   │   └── name: :B
        │   │   ├── child:
        │   │   │   @ ConstantReadNode (location: (5,3)-(5,4))
        │   │   │   └── name: :A
        │   │   └── delimiter_loc: (5,1)-(5,3) = "::"
        │   ├── operator_loc: (5,5)-(5,7) = "+="
        │   ├── value:
        │   │   @ IntegerNode (location: (5,8)-(5,9))
        │   │   ├── flags: decimal
        │   │   └── value: 1
        │   └── operator: :+
        ├── @ DefNode (location: (7,0)-(7,21))
        │   ├── name: :x
        │   ├── name_loc: (7,4)-(7,5) = "x"
        │   ├── receiver: ∅
        │   ├── parameters: ∅
        │   ├── body:
        │   │   @ StatementsNode (location: (7,7)-(7,16))
        │   │   └── body: (length: 1)
        │   │       └── @ ConstantPathOrWriteNode (location: (7,7)-(7,16))
        │   │           ├── target:
        │   │           │   @ ConstantPathNode (location: (7,7)-(7,10))
        │   │           │   ├── parent: ∅
        │   │           │   ├── child:
        │   │           │   │   @ ConstantReadNode (location: (7,9)-(7,10))
        │   │           │   │   └── name: :A
        │   │           │   └── delimiter_loc: (7,7)-(7,9) = "::"
        │   │           ├── operator_loc: (7,11)-(7,14) = "||="
        │   │           └── value:
        │   │               @ IntegerNode (location: (7,15)-(7,16))
        │   │               ├── flags: decimal
        │   │               └── value: 1
        │   ├── locals: []
        │   ├── def_keyword_loc: (7,0)-(7,3) = "def"
        │   ├── operator_loc: ∅
        │   ├── lparen_loc: ∅
        │   ├── rparen_loc: ∅
        │   ├── equal_loc: ∅
        │   └── end_keyword_loc: (7,18)-(7,21) = "end"
        └── @ DefNode (location: (9,0)-(9,25))
            ├── name: :x
            ├── name_loc: (9,4)-(9,5) = "x"
            ├── receiver: ∅
            ├── parameters: ∅
            ├── body:
            │   @ StatementsNode (location: (9,7)-(9,20))
            │   └── body: (length: 1)
            │       └── @ ConstantPathOrWriteNode (location: (9,7)-(9,20))
            │           ├── target:
            │           │   @ ConstantPathNode (location: (9,7)-(9,14))
            │           │   ├── parent:
            │           │   │   @ SelfNode (location: (9,7)-(9,11))
            │           │   ├── child:
            │           │   │   @ ConstantReadNode (location: (9,13)-(9,14))
            │           │   │   └── name: :A
            │           │   └── delimiter_loc: (9,11)-(9,13) = "::"
            │           ├── operator_loc: (9,15)-(9,18) = "||="
            │           └── value:
            │               @ IntegerNode (location: (9,19)-(9,20))
            │               ├── flags: decimal
            │               └── value: 1
            ├── locals: []
            ├── def_keyword_loc: (9,0)-(9,3) = "def"
            ├── operator_loc: ∅
            ├── lparen_loc: ∅
            ├── rparen_loc: ∅
            ├── equal_loc: ∅
            └── end_keyword_loc: (9,22)-(9,25) = "end"