@ ProgramNode (location: (1,0)-(1,12))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,12))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,12))
            ├── flags: ∅
            ├── receiver:
            │   @ CallNode (location: (1,0)-(1,1))
            │   ├── flags: variable_call
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── name: :a
            │   ├── message_loc: (1,0)-(1,1) = "a"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   └── block: ∅
            ├── call_operator_loc: (1,1)-(1,3) = "::"
            ├── name: :b
            ├── message_loc: (1,3)-(1,4) = "b"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,5)-(1,8))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ ParenthesesNode (location: (1,5)-(1,8))
            │           ├── body:
            │           │   @ StatementsNode (location: (1,6)-(1,7))
            │           │   └── body: (length: 1)
            │           │       └── @ IntegerNode (location: (1,6)-(1,7))
            │           │           └── flags: decimal
            │           ├── opening_loc: (1,5)-(1,6) = "("
            │           └── closing_loc: (1,7)-(1,8) = ")"
            ├── closing_loc: ∅
            └── block:
                @ BlockNode (location: (1,9)-(1,12))
                ├── locals: []
                ├── locals_body_index: 0
                ├── parameters: ∅
                ├── body:
                │   @ StatementsNode (location: (1,10)-(1,11))
                │   └── body: (length: 1)
                │       └── @ CallNode (location: (1,10)-(1,11))
                │           ├── flags: variable_call
                │           ├── receiver: ∅
                │           ├── call_operator_loc: ∅
                │           ├── name: :c
                │           ├── message_loc: (1,10)-(1,11) = "c"
                │           ├── opening_loc: ∅
                │           ├── arguments: ∅
                │           ├── closing_loc: ∅
                │           └── block: ∅
                ├── opening_loc: (1,9)-(1,10) = "{"
                └── closing_loc: (1,11)-(1,12) = "}"
