@ ProgramNode (location: (1,0)-(3,34))
├── flags: ∅
├── locals: [:a]
└── statements:
    @ StatementsNode (location: (1,0)-(3,34))
    ├── flags: ∅
    └── body: (length: 3)
        ├── @ LocalVariableWriteNode (location: (1,0)-(1,5))
        │   ├── flags: newline
        │   ├── name: :a
        │   ├── depth: 0
        │   ├── name_loc: (1,0)-(1,1) = "a"
        │   ├── value:
        │   │   @ IntegerNode (location: (1,4)-(1,5))
        │   │   ├── flags: static_literal, decimal
        │   │   └── value: 1
        │   └── operator_loc: (1,2)-(1,3) = "="
        ├── @ CallNode (location: (1,7)-(1,13))
        │   ├── flags: newline, ignore_visibility
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── name: :a
        │   ├── message_loc: (1,7)-(1,8) = "a"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (1,9)-(1,13))
        │   │   ├── flags: contains_keywords
        │   │   └── arguments: (length: 1)
        │   │       └── @ KeywordHashNode (location: (1,9)-(1,13))
        │   │           ├── flags: symbol_keys
        │   │           └── elements: (length: 1)
        │   │               └── @ AssocNode (location: (1,9)-(1,13))
        │   │                   ├── flags: static_literal
        │   │                   ├── key:
        │   │                   │   @ SymbolNode (location: (1,9)-(1,11))
        │   │                   │   ├── flags: static_literal, forced_us_ascii_encoding
        │   │                   │   ├── opening_loc: ∅
        │   │                   │   ├── value_loc: (1,9)-(1,10) = "b"
        │   │                   │   ├── closing_loc: (1,10)-(1,11) = ":"
        │   │                   │   └── unescaped: "b"
        │   │                   ├── value:
        │   │                   │   @ IntegerNode (location: (1,12)-(1,13))
        │   │                   │   ├── flags: static_literal, decimal
        │   │                   │   └── value: 1
        │   │                   └── operator_loc: ∅
        │   ├── closing_loc: ∅
        │   └── block: ∅
        └── @ DefNode (location: (3,0)-(3,34))
            ├── flags: newline
            ├── name: :foo
            ├── name_loc: (3,4)-(3,7) = "foo"
            ├── receiver: ∅
            ├── parameters:
            │   @ ParametersNode (location: (3,8)-(3,13))
            │   ├── flags: ∅
            │   ├── requireds: (length: 1)
            │   │   └── @ RequiredParameterNode (location: (3,8)-(3,13))
            │   │       ├── flags: ∅
            │   │       └── name: :raise
            │   ├── optionals: (length: 0)
            │   ├── rest: ∅
            │   ├── posts: (length: 0)
            │   ├── keywords: (length: 0)
            │   ├── keyword_rest: ∅
            │   └── block: ∅
            ├── body:
            │   @ StatementsNode (location: (3,15)-(3,29))
            │   ├── flags: ∅
            │   └── body: (length: 1)
            │       └── @ CallNode (location: (3,15)-(3,29))
            │           ├── flags: newline, ignore_visibility
            │           ├── receiver: ∅
            │           ├── call_operator_loc: ∅
            │           ├── name: :raise
            │           ├── message_loc: (3,15)-(3,20) = "raise"
            │           ├── opening_loc: ∅
            │           ├── arguments:
            │           │   @ ArgumentsNode (location: (3,21)-(3,29))
            │           │   ├── flags: ∅
            │           │   └── arguments: (length: 2)
            │           │       ├── @ ConstantPathNode (location: (3,21)-(3,25))
            │           │       │   ├── flags: ∅
            │           │       │   ├── parent:
            │           │       │   │   @ ConstantReadNode (location: (3,21)-(3,22))
            │           │       │   │   ├── flags: ∅
            │           │       │   │   └── name: :A
            │           │       │   ├── name: :B
            │           │       │   ├── delimiter_loc: (3,22)-(3,24) = "::"
            │           │       │   └── name_loc: (3,24)-(3,25) = "B"
            │           │       └── @ StringNode (location: (3,27)-(3,29))
            │           │           ├── flags: ∅
            │           │           ├── opening_loc: (3,27)-(3,28) = "'"
            │           │           ├── content_loc: (3,28)-(3,28) = ""
            │           │           ├── closing_loc: (3,28)-(3,29) = "'"
            │           │           └── unescaped: ""
            │           ├── closing_loc: ∅
            │           └── block: ∅
            ├── locals: [:raise]
            ├── def_keyword_loc: (3,0)-(3,3) = "def"
            ├── operator_loc: ∅
            ├── lparen_loc: ∅
            ├── rparen_loc: ∅
            ├── equal_loc: ∅
            └── end_keyword_loc: (3,31)-(3,34) = "end"
