@ ProgramNode (location: (1,0)-(1,16))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,16))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,16))
            ├── flags: newline, ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :a
            ├── message_loc: (1,0)-(1,1) = "a"
            ├── opening_loc: (1,1)-(1,2) = "("
            ├── arguments:
            │   @ ArgumentsNode (location: (1,2)-(1,15))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ ArrayNode (location: (1,2)-(1,15))
            │           ├── flags: ∅
            │           ├── elements: (length: 2)
            │           │   ├── @ SymbolNode (location: (1,3)-(1,5))
            │           │   │   ├── flags: static_literal, forced_us_ascii_encoding
            │           │   │   ├── opening_loc: (1,3)-(1,4) = ":"
            │           │   │   ├── value_loc: (1,4)-(1,5) = "b"
            │           │   │   ├── closing_loc: ∅
            │           │   │   └── unescaped: "b"
            │           │   └── @ KeywordHashNode (location: (1,7)-(1,14))
            │           │       ├── flags: symbol_keys
            │           │       └── elements: (length: 1)
            │           │           └── @ AssocNode (location: (1,7)-(1,14))
            │           │               ├── flags: static_literal
            │           │               ├── key:
            │           │               │   @ SymbolNode (location: (1,7)-(1,9))
            │           │               │   ├── flags: static_literal, forced_us_ascii_encoding
            │           │               │   ├── opening_loc: (1,7)-(1,8) = ":"
            │           │               │   ├── value_loc: (1,8)-(1,9) = "c"
            │           │               │   ├── closing_loc: ∅
            │           │               │   └── unescaped: "c"
            │           │               ├── value:
            │           │               │   @ IntegerNode (location: (1,13)-(1,14))
            │           │               │   ├── flags: static_literal, decimal
            │           │               │   └── value: 1
            │           │               └── operator_loc: (1,10)-(1,12) = "=>"
            │           ├── opening_loc: (1,2)-(1,3) = "["
            │           └── closing_loc: (1,14)-(1,15) = "]"
            ├── closing_loc: (1,15)-(1,16) = ")"
            └── block: ∅
