@ ProgramNode (location: (1,0)-(1,30))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,30))
    └── body: (length: 1)
        └── @ CaseNode (location: (1,0)-(1,30))
            ├── predicate:
            │   @ CallNode (location: (1,5)-(1,8))
            │   ├── flags: variable_call
            │   ├── receiver: ∅
            │   ├── call_operator_loc: ∅
            │   ├── name: :foo
            │   ├── message_loc: (1,5)-(1,8) = "foo"
            │   ├── opening_loc: ∅
            │   ├── arguments: ∅
            │   ├── closing_loc: ∅
            │   └── block: ∅
            ├── conditions: (length: 1)
            │   └── @ WhenNode (location: (1,10)-(1,25))
            │       ├── keyword_loc: (1,10)-(1,14) = "when"
            │       ├── conditions: (length: 1)
            │       │   └── @ StringNode (location: (1,15)-(1,20))
            │       │       ├── flags: ∅
            │       │       ├── opening_loc: (1,15)-(1,16) = "'"
            │       │       ├── content_loc: (1,16)-(1,19) = "bar"
            │       │       ├── closing_loc: (1,19)-(1,20) = "'"
            │       │       └── unescaped: "bar"
            │       └── statements:
            │           @ StatementsNode (location: (1,22)-(1,25))
            │           └── body: (length: 1)
            │               └── @ CallNode (location: (1,22)-(1,25))
            │                   ├── flags: variable_call
            │                   ├── receiver: ∅
            │                   ├── call_operator_loc: ∅
            │                   ├── name: :bar
            │                   ├── message_loc: (1,22)-(1,25) = "bar"
            │                   ├── opening_loc: ∅
            │                   ├── arguments: ∅
            │                   ├── closing_loc: ∅
            │                   └── block: ∅
            ├── consequent: ∅
            ├── case_keyword_loc: (1,0)-(1,4) = "case"
            └── end_keyword_loc: (1,27)-(1,30) = "end"
