@ ProgramNode (location: (1,0)-(1,17))
├── flags: ∅
├── locals: [:a]
└── statements:
    @ StatementsNode (location: (1,0)-(1,17))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ LocalVariableWriteNode (location: (1,0)-(1,17))
            ├── flags: newline
            ├── name: :a
            ├── depth: 0
            ├── name_loc: (1,0)-(1,1) = "a"
            ├── value:
            │   @ IfNode (location: (1,2)-(1,17))
            │   ├── flags: newline
            │   ├── if_keyword_loc: ∅
            │   ├── predicate:
            │   │   @ CallNode (location: (1,2)-(1,3))
            │   │   ├── flags: variable_call, ignore_visibility
            │   │   ├── receiver: ∅
            │   │   ├── call_operator_loc: ∅
            │   │   ├── name: :b
            │   │   ├── message_loc: (1,2)-(1,3) = "b"
            │   │   ├── opening_loc: ∅
            │   │   ├── arguments: ∅
            │   │   ├── closing_loc: ∅
            │   │   └── block: ∅
            │   ├── then_keyword_loc: (1,4)-(1,5) = "?"
            │   ├── statements:
            │   │   @ StatementsNode (location: (1,6)-(1,10))
            │   │   ├── flags: ∅
            │   │   └── body: (length: 1)
            │   │       └── @ TrueNode (location: (1,6)-(1,10))
            │   │           └── flags: newline, static_literal
            │   ├── subsequent:
            │   │   @ ElseNode (location: (1,10)-(1,17))
            │   │   ├── flags: ∅
            │   │   ├── else_keyword_loc: (1,10)-(1,11) = ":"
            │   │   ├── statements:
            │   │   │   @ StatementsNode (location: (1,12)-(1,17))
            │   │   │   ├── flags: ∅
            │   │   │   └── body: (length: 1)
            │   │   │       └── @ FalseNode (location: (1,12)-(1,17))
            │   │   │           └── flags: newline, static_literal
            │   │   └── end_keyword_loc: ∅
            │   └── end_keyword_loc: ∅
            └── operator_loc: (1,1)-(1,2) = "="
