@ ProgramNode (location: (1,0)-(10,17))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(10,17))
    └── body: (length: 10)
        ├── @ 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: ∅
        ├── @ InstanceVariableReadNode (location: (2,0)-(2,2))
        │   └── name: :@a
        ├── @ ClassVariableReadNode (location: (3,0)-(3,3))
        │   └── name: :@@a
        ├── @ GlobalVariableReadNode (location: (4,0)-(4,2))
        │   └── name: :$a
        ├── @ NumberedReferenceReadNode (location: (5,0)-(5,2))
        │   └── number: 1
        ├── @ BackReferenceReadNode (location: (6,0)-(6,2))
        │   └── name: :$`
        ├── @ ConstantReadNode (location: (7,0)-(7,5))
        │   └── name: :CONST
        ├── @ ConstantPathNode (location: (8,0)-(8,13))
        │   ├── parent:
        │   │   @ ConstantReadNode (location: (8,0)-(8,6))
        │   │   └── name: :SCOPED
        │   ├── name: :CONST
        │   ├── delimiter_loc: (8,6)-(8,8) = "::"
        │   └── name_loc: (8,8)-(8,13) = "CONST"
        ├── @ ConstantPathNode (location: (9,0)-(9,10))
        │   ├── parent: ∅
        │   ├── name: :TOPLEVEL
        │   ├── delimiter_loc: (9,0)-(9,2) = "::"
        │   └── name_loc: (9,2)-(9,10) = "TOPLEVEL"
        └── @ ConstantPathNode (location: (10,0)-(10,17))
            ├── parent:
            │   @ ConstantPathNode (location: (10,0)-(10,10))
            │   ├── parent: ∅
            │   ├── name: :TOPLEVEL
            │   ├── delimiter_loc: (10,0)-(10,2) = "::"
            │   └── name_loc: (10,2)-(10,10) = "TOPLEVEL"
            ├── name: :CONST
            ├── delimiter_loc: (10,10)-(10,12) = "::"
            └── name_loc: (10,12)-(10,17) = "CONST"