@ ProgramNode (location: (0...8))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...8))
    └── body: (length: 1)
        └── @ ConstantWriteNode (location: (0...8))
            ├── name: :Foo
            ├── name_loc: (0...3) = "Foo"
            ├── value:
            │   @ IntegerNode (location: (6...8))
            │   └── flags: decimal
            └── operator_loc: (4...5) = "="
