@ ProgramNode (location: (1,0)-(1,11))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,11))
    └── body: (length: 1)
        └── @ CallNode (location: (1,0)-(1,11))
            ├── flags: safe_navigation
            ├── receiver:
            │   @ CallNode (location: (1,0)-(1,3))
            │   ├── flags: variable_call
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── name: :foo
            │   ├── message_loc: (1,0)-(1,3) = "foo"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   └── block: ∅
            ├── call_operator_loc: (1,3)-(1,5) = "&."
            ├── name: :bar
            ├── message_loc: (1,5)-(1,8) = "bar"
            ├── opening_loc: ∅
            ├── arguments: ∅
            ├── closing_loc: ∅
            └── block:
                @ BlockNode (location: (1,9)-(1,11))
                ├── locals: []
                ├── locals_body_index: 0
                ├── parameters: ∅
                ├── body: ∅
                ├── opening_loc: (1,9)-(1,10) = "{"
                └── closing_loc: (1,10)-(1,11) = "}"
