@ ProgramNode (location: (1,0)-(1,7))
├── locals: [:n]
└── statements:
    @ StatementsNode (location: (1,0)-(1,7))
    └── body: (length: 1)
        └── @ MatchRequiredNode (location: (1,0)-(1,7))
            ├── value:
            │   @ IntegerNode (location: (1,0)-(1,2))
            │   ├── flags: decimal
            │   └── value: 42
            ├── pattern:
            │   @ LocalVariableTargetNode (location: (1,6)-(1,7))
            │   ├── name: :n
            │   └── depth: 0
            └── operator_loc: (1,3)-(1,5) = "=>"