@ ProgramNode (location: (0...10))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...10))
    └── body: (length: 1)
        └── @ IfNode (location: (0...10))
            ├── if_keyword_loc: (0...2) = "if"
            ├── predicate:
            │   @ IntegerNode (location: (3...5))
            │   └── flags: decimal
            ├── statements: ∅
            ├── consequent: ∅
            └── end_keyword_loc: (7...10) = "end"
