@ ProgramNode (location: (1,0)-(1,10))
├── flags: ∅
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,10))
    ├── flags: ∅
    └── body: (length: 1)
        └── @ RegularExpressionNode (location: (1,0)-(1,10))
            ├── flags: newline, static_literal, ignore_case, multi_line, forced_us_ascii_encoding
            ├── opening_loc: (1,0)-(1,1) = "/"
            ├── content_loc: (1,1)-(1,7) = "source"
            ├── closing_loc: (1,7)-(1,10) = "/im"
            └── unescaped: "source"
