@ ProgramNode (location: (0...18))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...18))
    └── body: (length: 1)
        └── @ IfNode (location: (0...18))
            ├── if_keyword_loc: (0...2) = "if"
            ├── predicate:
            │   @ ParenthesesNode (location: (3...8))
            │   ├── body:
            │   │   @ StatementsNode (location: (4...7))
            │   │   └── body: (length: 1)
            │   │       └── @ CallNode (location: (4...7))
            │   │           ├── receiver: ∅
            │   │           ├── call_operator_loc: ∅
            │   │           ├── message_loc: (4...7) = "bar"
            │   │           ├── opening_loc: ∅
            │   │           ├── arguments: ∅
            │   │           ├── closing_loc: ∅
            │   │           ├── block: ∅
            │   │           ├── flags: variable_call
            │   │           └── name: "bar"
            │   ├── opening_loc: (3...4) = "("
            │   └── closing_loc: (7...8) = ")"
            ├── statements:
            │   @ StatementsNode (location: (10...13))
            │   └── body: (length: 1)
            │       └── @ CallNode (location: (10...13))
            │           ├── receiver: ∅
            │           ├── call_operator_loc: ∅
            │           ├── message_loc: (10...13) = "foo"
            │           ├── opening_loc: ∅
            │           ├── arguments: ∅
            │           ├── closing_loc: ∅
            │           ├── block: ∅
            │           ├── flags: variable_call
            │           └── name: "foo"
            ├── consequent: ∅
            └── end_keyword_loc: (15...18) = "end"