@ ProgramNode (location: (0...46))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...46))
    └── body: (length: 4)
        ├── @ CallNode (location: (0...11))
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── message_loc: (0...1) = "f"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (2...11))
        │   │   └── arguments: (length: 1)
        │   │       └── @ LambdaNode (location: (2...11))
        │   │           ├── locals: []
        │   │           ├── operator_loc: (2...4) = "->"
        │   │           ├── opening_loc: (5...7) = "do"
        │   │           ├── closing_loc: (8...11) = "end"
        │   │           ├── parameters: ∅
        │   │           └── body: ∅
        │   ├── closing_loc: ∅
        │   ├── block: ∅
        │   ├── flags: ∅
        │   └── name: "f"
        ├── @ CallNode (location: (13...20))
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── message_loc: (13...14) = "f"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (15...20))
        │   │   └── arguments: (length: 1)
        │   │       └── @ LambdaNode (location: (15...20))
        │   │           ├── locals: []
        │   │           ├── operator_loc: (15...17) = "->"
        │   │           ├── opening_loc: (18...19) = "{"
        │   │           ├── closing_loc: (19...20) = "}"
        │   │           ├── parameters: ∅
        │   │           └── body: ∅
        │   ├── closing_loc: ∅
        │   ├── block: ∅
        │   ├── flags: ∅
        │   └── name: "f"
        ├── @ CallNode (location: (22...35))
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── message_loc: (22...23) = "f"
        │   ├── opening_loc: ∅
        │   ├── arguments:
        │   │   @ ArgumentsNode (location: (24...35))
        │   │   └── arguments: (length: 1)
        │   │       └── @ LambdaNode (location: (24...35))
        │   │           ├── locals: []
        │   │           ├── operator_loc: (24...26) = "->"
        │   │           ├── opening_loc: (29...31) = "do"
        │   │           ├── closing_loc: (32...35) = "end"
        │   │           ├── parameters:
        │   │           │   @ BlockParametersNode (location: (26...28))
        │   │           │   ├── parameters: ∅
        │   │           │   ├── locals: (length: 0)
        │   │           │   ├── opening_loc: (26...27) = "("
        │   │           │   └── closing_loc: (27...28) = ")"
        │   │           └── body: ∅
        │   ├── closing_loc: ∅
        │   ├── block: ∅
        │   ├── flags: ∅
        │   └── name: "f"
        └── @ CallNode (location: (37...46))
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── message_loc: (37...38) = "f"
            ├── opening_loc: ∅
            ├── arguments:
            │   @ ArgumentsNode (location: (39...46))
            │   └── arguments: (length: 1)
            │       └── @ LambdaNode (location: (39...46))
            │           ├── locals: []
            │           ├── operator_loc: (39...41) = "->"
            │           ├── opening_loc: (44...45) = "{"
            │           ├── closing_loc: (45...46) = "}"
            │           ├── parameters:
            │           │   @ BlockParametersNode (location: (41...43))
            │           │   ├── parameters: ∅
            │           │   ├── locals: (length: 0)
            │           │   ├── opening_loc: (41...42) = "("
            │           │   └── closing_loc: (42...43) = ")"
            │           └── body: ∅
            ├── closing_loc: ∅
            ├── block: ∅
            ├── flags: ∅
            └── name: "f"
