@ ProgramNode (location: (1,0)-(5,22))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(5,22))
    └── body: (length: 3)
        ├── @ DefNode (location: (1,0)-(1,11))
        │   ├── name: :foo
        │   ├── name_loc: (1,4)-(1,7) = "foo"
        │   ├── receiver: ∅
        │   ├── parameters: ∅
        │   ├── body:
        │   │   @ StatementsNode (location: (1,10)-(1,11))
        │   │   └── body: (length: 1)
        │   │       └── @ IntegerNode (location: (1,10)-(1,11))
        │   │           └── flags: decimal
        │   ├── locals: []
        │   ├── def_keyword_loc: (1,0)-(1,3) = "def"
        │   ├── operator_loc: ∅
        │   ├── lparen_loc: ∅
        │   ├── rparen_loc: ∅
        │   ├── equal_loc: (1,8)-(1,9) = "="
        │   └── end_keyword_loc: ∅
        ├── @ DefNode (location: (3,0)-(3,14))
        │   ├── name: :bar
        │   ├── name_loc: (3,4)-(3,7) = "bar"
        │   ├── receiver: ∅
        │   ├── parameters: ∅
        │   ├── body:
        │   │   @ StatementsNode (location: (3,10)-(3,14))
        │   │   └── body: (length: 1)
        │   │       └── @ CallNode (location: (3,10)-(3,14))
        │   │           ├── receiver: ∅
        │   │           ├── call_operator_loc: ∅
        │   │           ├── message_loc: (3,10)-(3,11) = "A"
        │   │           ├── opening_loc: ∅
        │   │           ├── arguments:
        │   │           │   @ ArgumentsNode (location: (3,12)-(3,14))
        │   │           │   ├── arguments: (length: 1)
        │   │           │   │   └── @ StringNode (location: (3,12)-(3,14))
        │   │           │   │       ├── flags: ∅
        │   │           │   │       ├── opening_loc: (3,12)-(3,13) = "\""
        │   │           │   │       ├── content_loc: (3,13)-(3,13) = ""
        │   │           │   │       ├── closing_loc: (3,13)-(3,14) = "\""
        │   │           │   │       └── unescaped: ""
        │   │           │   └── flags: ∅
        │   │           ├── closing_loc: ∅
        │   │           ├── block: ∅
        │   │           ├── flags: ∅
        │   │           └── name: :A
        │   ├── locals: []
        │   ├── def_keyword_loc: (3,0)-(3,3) = "def"
        │   ├── operator_loc: ∅
        │   ├── lparen_loc: ∅
        │   ├── rparen_loc: ∅
        │   ├── equal_loc: (3,8)-(3,9) = "="
        │   └── end_keyword_loc: ∅
        └── @ DefNode (location: (5,0)-(5,22))
            ├── name: :method
            ├── name_loc: (5,4)-(5,10) = "method"
            ├── receiver: ∅
            ├── parameters: ∅
            ├── body:
            │   @ StatementsNode (location: (5,13)-(5,22))
            │   └── body: (length: 1)
            │       └── @ CallNode (location: (5,13)-(5,22))
            │           ├── receiver:
            │           │   @ CallNode (location: (5,13)-(5,18))
            │           │   ├── receiver:
            │           │   │   @ IntegerNode (location: (5,13)-(5,14))
            │           │   │   └── flags: decimal
            │           │   ├── call_operator_loc: ∅
            │           │   ├── message_loc: (5,15)-(5,16) = "+"
            │           │   ├── opening_loc: ∅
            │           │   ├── arguments:
            │           │   │   @ ArgumentsNode (location: (5,17)-(5,18))
            │           │   │   ├── arguments: (length: 1)
            │           │   │   │   └── @ IntegerNode (location: (5,17)-(5,18))
            │           │   │   │       └── flags: decimal
            │           │   │   └── flags: ∅
            │           │   ├── closing_loc: ∅
            │           │   ├── block: ∅
            │           │   ├── flags: ∅
            │           │   └── name: :+
            │           ├── call_operator_loc: ∅
            │           ├── message_loc: (5,19)-(5,20) = "+"
            │           ├── opening_loc: ∅
            │           ├── arguments:
            │           │   @ ArgumentsNode (location: (5,21)-(5,22))
            │           │   ├── arguments: (length: 1)
            │           │   │   └── @ IntegerNode (location: (5,21)-(5,22))
            │           │   │       └── flags: decimal
            │           │   └── flags: ∅
            │           ├── closing_loc: ∅
            │           ├── block: ∅
            │           ├── flags: ∅
            │           └── name: :+
            ├── locals: []
            ├── def_keyword_loc: (5,0)-(5,3) = "def"
            ├── operator_loc: ∅
            ├── lparen_loc: ∅
            ├── rparen_loc: ∅
            ├── equal_loc: (5,11)-(5,12) = "="
            └── end_keyword_loc: ∅
