@ ProgramNode (location: (1,0)-(1,16))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,16))
    └── body: (length: 1)
        └── @ IndexOrWriteNode (location: (1,0)-(1,16))
            ├── flags: ∅
            ├── receiver:
            │   @ CallNode (location: (1,0)-(1,1))
            │   ├── flags: variable_call, ignore_visibility
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── name: :a
            │   ├── message_loc: (1,0)-(1,1) = "a"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   └── block: ∅
            ├── call_operator_loc: ∅
            ├── opening_loc: (1,1)-(1,2) = "["
            ├── arguments:
            │   @ ArgumentsNode (location: (1,2)-(1,4))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ SymbolNode (location: (1,2)-(1,4))
            │           ├── flags: forced_us_ascii_encoding
            │           ├── opening_loc: (1,2)-(1,3) = ":"
            │           ├── value_loc: (1,3)-(1,4) = "b"
            │           ├── closing_loc: ∅
            │           └── unescaped: "b"
            ├── closing_loc: (1,4)-(1,5) = "]"
            ├── block: ∅
            ├── operator_loc: (1,6)-(1,9) = "||="
            └── value:
                @ CallNode (location: (1,10)-(1,16))
                ├── flags: ignore_visibility
                ├── receiver: ∅
                ├── call_operator_loc: ∅
                ├── name: :c
                ├── message_loc: (1,10)-(1,11) = "c"
                ├── opening_loc: ∅
                ├── arguments:
                │   @ ArgumentsNode (location: (1,12)-(1,16))
                │   ├── flags: ∅
                │   └── arguments: (length: 2)
                │       ├── @ IntegerNode (location: (1,12)-(1,13))
                │       │   ├── flags: decimal
                │       │   └── value: 1
                │       └── @ IntegerNode (location: (1,15)-(1,16))
                │           ├── flags: decimal
                │           └── value: 2
                ├── closing_loc: ∅
                └── block: ∅