@ ProgramNode (location: (1,0)-(1,17))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,17))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,17))
            ├── flags: ∅
            ├── receiver:
            │   @ CallNode (location: (1,0)-(1,11))
            │   ├── flags: ignore_visibility
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── name: :a
            │   ├── message_loc: (1,0)-(1,1) = "a"
            │   ├── opening_loc: ∅
            │   ├── 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: ∅
            │   └── block:
            │       @ BlockNode (location: (1,5)-(1,11))
            │       ├── locals: []
            │       ├── parameters: ∅
            │       ├── body: ∅
            │       ├── opening_loc: (1,5)-(1,7) = "do"
            │       └── closing_loc: (1,8)-(1,11) = "end"
            ├── call_operator_loc: (1,11)-(1,13) = "::"
            ├── name: :c
            ├── message_loc: (1,13)-(1,14) = "c"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,15)-(1,17))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ SymbolNode (location: (1,15)-(1,17))
            │           ├── flags: forced_us_ascii_encoding
            │           ├── opening_loc: (1,15)-(1,16) = ":"
            │           ├── value_loc: (1,16)-(1,17) = "d"
            │           ├── closing_loc: ∅
            │           └── unescaped: "d"
            ├── closing_loc: ∅
            └── block: ∅