@ ProgramNode (location: (1,0)-(1,30))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,30))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,30))
            ├── flags: ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :p
            ├── message_loc: (1,0)-(1,1) = "p"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,2)-(1,30))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ DefNode (location: (1,2)-(1,30))
            │           ├── name: :b
            │           ├── name_loc: (1,11)-(1,12) = "b"
            │           ├── receiver:
            │           │   @ SelfNode (location: (1,6)-(1,10))
            │           ├── parameters: ∅
            │           ├── body:
            │           │   @ StatementsNode (location: (1,14)-(1,25))
            │           │   └── body: (length: 1)
            │           │       └── @ CallNode (location: (1,14)-(1,25))
            │           │           ├── flags: ∅
            │           │           ├── receiver:
            │           │           │   @ CallNode (location: (1,14)-(1,15))
            │           │           │   ├── flags: variable_call, ignore_visibility
            │           │           │   ├── receiver: ∅
            │           │           │   ├── call_operator_loc: ∅
            │           │           │   ├── name: :x
            │           │           │   ├── message_loc: (1,14)-(1,15) = "x"
            │           │           │   ├── opening_loc: ∅
            │           │           │   ├── arguments: ∅
            │           │           │   ├── closing_loc: ∅
            │           │           │   └── block: ∅
            │           │           ├── call_operator_loc: (1,15)-(1,16) = "."
            │           │           ├── name: :y
            │           │           ├── message_loc: (1,16)-(1,17) = "y"
            │           │           ├── opening_loc: ∅
            │           │           ├── arguments: ∅
            │           │           ├── closing_loc: ∅
            │           │           └── block:
            │           │               @ BlockNode (location: (1,18)-(1,25))
            │           │               ├── locals: []
            │           │               ├── parameters: ∅
            │           │               ├── body: ∅
            │           │               ├── opening_loc: (1,18)-(1,20) = "do"
            │           │               └── closing_loc: (1,22)-(1,25) = "end"
            │           ├── locals: []
            │           ├── def_keyword_loc: (1,2)-(1,5) = "def"
            │           ├── operator_loc: (1,10)-(1,11) = "."
            │           ├── lparen_loc: ∅
            │           ├── rparen_loc: ∅
            │           ├── equal_loc: ∅
            │           └── end_keyword_loc: (1,27)-(1,30) = "end"
            ├── closing_loc: ∅
            └── block: ∅