@ ProgramNode (location: (1,0)-(3,11))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(3,11))
    └── body: (length: 2)
        ├── @ CallNode (location: (1,0)-(1,18))
        │   ├── flags: ignore_visibility
        │   ├── receiver: ∅
        │   ├── call_operator_loc: ∅
        │   ├── name: :m
        │   ├── message_loc: (1,0)-(1,1) = "m"
        │   ├── opening_loc: ∅
        │   ├── arguments: ∅
        │   ├── closing_loc: ∅
        │   └── block:
        │       @ BlockNode (location: (1,2)-(1,18))
        │       ├── locals: [:foo, :bar]
        │       ├── parameters:
        │       │   @ BlockParametersNode (location: (1,4)-(1,16))
        │       │   ├── parameters:
        │       │   │   @ ParametersNode (location: (1,5)-(1,15))
        │       │   │   ├── requireds: (length: 1)
        │       │   │   │   └── @ MultiTargetNode (location: (1,5)-(1,15))
        │       │   │   │       ├── lefts: (length: 2)
        │       │   │   │       │   ├── @ RequiredParameterNode (location: (1,6)-(1,9))
        │       │   │   │       │   │   ├── flags: ∅
        │       │   │   │       │   │   └── name: :foo
        │       │   │   │       │   └── @ RequiredParameterNode (location: (1,11)-(1,14))
        │       │   │   │       │       ├── flags: ∅
        │       │   │   │       │       └── name: :bar
        │       │   │   │       ├── rest: ∅
        │       │   │   │       ├── rights: (length: 0)
        │       │   │   │       ├── lparen_loc: (1,5)-(1,6) = "("
        │       │   │   │       └── rparen_loc: (1,14)-(1,15) = ")"
        │       │   │   ├── optionals: (length: 0)
        │       │   │   ├── rest: ∅
        │       │   │   ├── posts: (length: 0)
        │       │   │   ├── keywords: (length: 0)
        │       │   │   ├── keyword_rest: ∅
        │       │   │   └── block: ∅
        │       │   ├── locals: (length: 0)
        │       │   ├── opening_loc: (1,4)-(1,5) = "|"
        │       │   └── closing_loc: (1,15)-(1,16) = "|"
        │       ├── body: ∅
        │       ├── opening_loc: (1,2)-(1,3) = "{"
        │       └── closing_loc: (1,17)-(1,18) = "}"
        └── @ CallNode (location: (3,0)-(3,11))
            ├── flags: ignore_visibility
            ├── receiver: ∅
            ├── call_operator_loc: ∅
            ├── name: :m
            ├── message_loc: (3,0)-(3,1) = "m"
            ├── opening_loc: ∅
            ├── arguments: ∅
            ├── closing_loc: ∅
            └── block:
                @ BlockNode (location: (3,2)-(3,11))
                ├── locals: [:foo]
                ├── parameters:
                │   @ BlockParametersNode (location: (3,4)-(3,9))
                │   ├── parameters:
                │   │   @ ParametersNode (location: (3,5)-(3,8))
                │   │   ├── requireds: (length: 1)
                │   │   │   └── @ RequiredParameterNode (location: (3,5)-(3,8))
                │   │   │       ├── flags: ∅
                │   │   │       └── name: :foo
                │   │   ├── optionals: (length: 0)
                │   │   ├── rest: ∅
                │   │   ├── posts: (length: 0)
                │   │   ├── keywords: (length: 0)
                │   │   ├── keyword_rest: ∅
                │   │   └── block: ∅
                │   ├── locals: (length: 0)
                │   ├── opening_loc: (3,4)-(3,5) = "|"
                │   └── closing_loc: (3,8)-(3,9) = "|"
                ├── body: ∅
                ├── opening_loc: (3,2)-(3,3) = "{"
                └── closing_loc: (3,10)-(3,11) = "}"
