@ ProgramNode (location: (0...80))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...80))
    └── body: (length: 6)
        ├── @ CallNode (location: (0...10))
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── message_loc: (0...6) = "lambda"
        │   ├── opening_loc: ∅
        │   ├── arguments: ∅
        │   ├── closing_loc: ∅
        │   ├── block:
        │   │   @ BlockNode (location: (7...10))
        │   │   ├── locals: []
        │   │   ├── parameters: ∅
        │   │   ├── body: ∅
        │   │   ├── opening_loc: (7...8) = "{"
        │   │   └── closing_loc: (9...10) = "}"
        │   ├── flags: ∅
        │   └── name: "lambda"
        ├── @ CallNode (location: (11...32))
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── message_loc: (11...17) = "lambda"
        │   ├── opening_loc: ∅
        │   ├── arguments: ∅
        │   ├── closing_loc: ∅
        │   ├── block:
        │   │   @ BlockNode (location: (18...32))
        │   │   ├── locals: [:a, :b]
        │   │   ├── parameters:
        │   │   │   @ BlockParametersNode (location: (20...26))
        │   │   │   ├── parameters:
        │   │   │   │   @ ParametersNode (location: (21...25))
        │   │   │   │   ├── requireds: (length: 2)
        │   │   │   │   │   ├── @ RequiredParameterNode (location: (21...22))
        │   │   │   │   │   │   └── name: :a
        │   │   │   │   │   └── @ RequiredParameterNode (location: (24...25))
        │   │   │   │   │       └── name: :b
        │   │   │   │   ├── optionals: (length: 0)
        │   │   │   │   ├── rest: ∅
        │   │   │   │   ├── posts: (length: 0)
        │   │   │   │   ├── keywords: (length: 0)
        │   │   │   │   ├── keyword_rest: ∅
        │   │   │   │   └── block: ∅
        │   │   │   ├── locals: (length: 0)
        │   │   │   ├── opening_loc: (20...21) = "|"
        │   │   │   └── closing_loc: (25...26) = "|"
        │   │   ├── body:
        │   │   │   @ StatementsNode (location: (29...30))
        │   │   │   └── body: (length: 1)
        │   │   │       └── @ LocalVariableReadNode (location: (29...30))
        │   │   │           ├── name: :a
        │   │   │           └── depth: 0
        │   │   ├── opening_loc: (18...19) = "{"
        │   │   └── closing_loc: (31...32) = "}"
        │   ├── flags: ∅
        │   └── name: "lambda"
        ├── @ LambdaNode (location: (33...41))
        │   ├── locals: []
        │   ├── operator_loc: (33...35) = "->"
        │   ├── opening_loc: (38...39) = "{"
        │   ├── closing_loc: (40...41) = "}"
        │   ├── parameters:
        │   │   @ BlockParametersNode (location: (35...37))
        │   │   ├── parameters: ∅
        │   │   ├── locals: (length: 0)
        │   │   ├── opening_loc: (35...36) = "("
        │   │   └── closing_loc: (36...37) = ")"
        │   └── body: ∅
        ├── @ LambdaNode (location: (42...51))
        │   ├── locals: [:a]
        │   ├── operator_loc: (42...44) = "->"
        │   ├── opening_loc: (48...49) = "{"
        │   ├── closing_loc: (50...51) = "}"
        │   ├── parameters:
        │   │   @ BlockParametersNode (location: (44...47))
        │   │   ├── parameters:
        │   │   │   @ ParametersNode (location: (45...46))
        │   │   │   ├── requireds: (length: 1)
        │   │   │   │   └── @ RequiredParameterNode (location: (45...46))
        │   │   │   │       └── name: :a
        │   │   │   ├── optionals: (length: 0)
        │   │   │   ├── rest: ∅
        │   │   │   ├── posts: (length: 0)
        │   │   │   ├── keywords: (length: 0)
        │   │   │   ├── keyword_rest: ∅
        │   │   │   └── block: ∅
        │   │   ├── locals: (length: 0)
        │   │   ├── opening_loc: (44...45) = "("
        │   │   └── closing_loc: (46...47) = ")"
        │   └── body: ∅
        ├── @ LambdaNode (location: (52...64))
        │   ├── locals: [:a, :b]
        │   ├── operator_loc: (52...54) = "->"
        │   ├── opening_loc: (61...62) = "{"
        │   ├── closing_loc: (63...64) = "}"
        │   ├── parameters:
        │   │   @ BlockParametersNode (location: (54...60))
        │   │   ├── parameters:
        │   │   │   @ ParametersNode (location: (55...59))
        │   │   │   ├── requireds: (length: 2)
        │   │   │   │   ├── @ RequiredParameterNode (location: (55...56))
        │   │   │   │   │   └── name: :a
        │   │   │   │   └── @ RequiredParameterNode (location: (58...59))
        │   │   │   │       └── name: :b
        │   │   │   ├── optionals: (length: 0)
        │   │   │   ├── rest: ∅
        │   │   │   ├── posts: (length: 0)
        │   │   │   ├── keywords: (length: 0)
        │   │   │   ├── keyword_rest: ∅
        │   │   │   └── block: ∅
        │   │   ├── locals: (length: 0)
        │   │   ├── opening_loc: (54...55) = "("
        │   │   └── closing_loc: (59...60) = ")"
        │   └── body: ∅
        └── @ LambdaNode (location: (65...80))
            ├── locals: [:a, :b, :c]
            ├── operator_loc: (65...67) = "->"
            ├── opening_loc: (77...78) = "{"
            ├── closing_loc: (79...80) = "}"
            ├── parameters:
            │   @ BlockParametersNode (location: (67...76))
            │   ├── parameters:
            │   │   @ ParametersNode (location: (68...72))
            │   │   ├── requireds: (length: 2)
            │   │   │   ├── @ RequiredParameterNode (location: (68...69))
            │   │   │   │   └── name: :a
            │   │   │   └── @ RequiredParameterNode (location: (71...72))
            │   │   │       └── name: :b
            │   │   ├── optionals: (length: 0)
            │   │   ├── rest: ∅
            │   │   ├── posts: (length: 0)
            │   │   ├── keywords: (length: 0)
            │   │   ├── keyword_rest: ∅
            │   │   └── block: ∅
            │   ├── locals: (length: 1)
            │   │   └── @ BlockLocalVariableNode (location: (74...75))
            │   │       └── name: :c
            │   ├── opening_loc: (67...68) = "("
            │   └── closing_loc: (75...76) = ")"
            └── body: ∅
