@ ProgramNode (location: (1,0)-(1,33))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,33))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,33))
            ├── flags: newline, ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :bar
            ├── message_loc: (1,0)-(1,3) = "bar"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (1,4)-(1,33))
            │   ├── flags: ∅
            │   └── arguments: (length: 1)
            │       └── @ DefNode (location: (1,4)-(1,33))
            │           ├── flags: ∅
            │           ├── name: :foo
            │           ├── name_loc: (1,8)-(1,11) = "foo"
            │           ├── receiver: ∅
            │           ├── parameters: ∅
            │           ├── body:
            │           │   @ StatementsNode (location: (1,13)-(1,29))
            │           │   ├── flags: ∅
            │           │   └── body: (length: 1)
            │           │       └── @ CallNode (location: (1,13)-(1,29))
            │           │           ├── flags: newline, ignore_visibility
            │           │           ├── receiver:
            │           │           │   @ SelfNode (location: (1,13)-(1,17))
            │           │           │   └── flags: ∅
            │           │           ├── call_operator_loc: (1,17)-(1,18) = "."
            │           │           ├── name: :each
            │           │           ├── message_loc: (1,18)-(1,22) = "each"
            │           │           ├── opening_loc: ∅
            │           │           ├── arguments: ∅
            │           │           ├── closing_loc: ∅
            │           │           └── block:
            │           │               @ BlockNode (location: (1,23)-(1,29))
            │           │               ├── flags: ∅
            │           │               ├── locals: []
            │           │               ├── parameters: ∅
            │           │               ├── body: ∅
            │           │               ├── opening_loc: (1,23)-(1,25) = "do"
            │           │               └── closing_loc: (1,26)-(1,29) = "end"
            │           ├── locals: []
            │           ├── def_keyword_loc: (1,4)-(1,7) = "def"
            │           ├── operator_loc: ∅
            │           ├── lparen_loc: ∅
            │           ├── rparen_loc: ∅
            │           ├── equal_loc: ∅
            │           └── end_keyword_loc: (1,30)-(1,33) = "end"
            ├── closing_loc: ∅
            └── block: ∅
