@ ProgramNode (location: (0...30))
├── locals: [:_]
└── statements:
    @ StatementsNode (location: (0...30))
    └── body: (length: 1)
        └── @ CaseNode (location: (0...30))
            ├── predicate:
            │   @ SymbolNode (location: (5...7))
            │   ├── opening_loc: (5...6) = ":"
            │   ├── value_loc: (6...7) = "a"
            │   ├── closing_loc: ∅
            │   └── unescaped: "a"
            ├── conditions: (length: 1)
            │   └── @ InNode (location: (8...26))
            │       ├── pattern:
            │       │   @ ArrayPatternNode (location: (11...17))
            │       │   ├── constant: ∅
            │       │   ├── requireds: (length: 1)
            │       │   │   └── @ SymbolNode (location: (11...13))
            │       │   │       ├── opening_loc: (11...12) = ":"
            │       │   │       ├── value_loc: (12...13) = "b"
            │       │   │       ├── closing_loc: ∅
            │       │   │       └── unescaped: "b"
            │       │   ├── rest:
            │       │   │   @ SplatNode (location: (15...17))
            │       │   │   ├── operator_loc: (15...16) = "*"
            │       │   │   └── expression:
            │       │   │       @ LocalVariableTargetNode (location: (16...17))
            │       │   │       ├── name: :_
            │       │   │       └── depth: 0
            │       │   ├── posts: (length: 0)
            │       │   ├── opening_loc: ∅
            │       │   └── closing_loc: ∅
            │       ├── statements:
            │       │   @ StatementsNode (location: (23...26))
            │       │   └── body: (length: 1)
            │       │       └── @ NilNode (location: (23...26))
            │       ├── in_loc: (8...10) = "in"
            │       └── then_loc: (18...22) = "then"
            ├── consequent: ∅
            ├── case_keyword_loc: (0...4) = "case"
            └── end_keyword_loc: (27...30) = "end"