@ ProgramNode (location: (1,0)-(3,13))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(3,13))
    └── body: (length: 2)
        ├── @ CallNode (location: (1,0)-(1,6))
        │   ├── flags: ∅
        │   ├── receiver:
        │   │   @ MatchLastLineNode (location: (1,1)-(1,6))
        │   │   ├── flags: forced_us_ascii_encoding
        │   │   ├── opening_loc: (1,1)-(1,2) = "/"
        │   │   ├── content_loc: (1,2)-(1,5) = "wat"
        │   │   ├── closing_loc: (1,5)-(1,6) = "/"
        │   │   └── unescaped: "wat"
        │   ├── call_operator_loc: ∅
        │   ├── name: :!
        │   ├── message_loc: (1,0)-(1,1) = "!"
        │   ├── opening_loc: ∅
        │   ├── arguments: ∅
        │   ├── closing_loc: ∅
        │   └── block: ∅
        └── @ IfNode (location: (3,0)-(3,13))
            ├── if_keyword_loc: (3,0)-(3,2) = "if"
            ├── predicate:
            │   @ MatchLastLineNode (location: (3,3)-(3,8))
            │   ├── flags: forced_us_ascii_encoding
            │   ├── opening_loc: (3,3)-(3,4) = "/"
            │   ├── content_loc: (3,4)-(3,7) = "wat"
            │   ├── closing_loc: (3,7)-(3,8) = "/"
            │   └── unescaped: "wat"
            ├── then_keyword_loc: ∅
            ├── statements: ∅
            ├── consequent: ∅
            └── end_keyword_loc: (3,10)-(3,13) = "end"