@ ProgramNode (location: (1,0)-(1,5))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,5))
    └── body: (length: 1)
        └── @ InterpolatedStringNode (location: (1,0)-(1,5))
            ├── flags: ∅
            ├── opening_loc: (1,0)-(1,5) = "<<EOS"
            ├── parts: (length: 3)
            │   ├── @ StringNode (location: (2,0)-(2,5))
            │   │   ├── flags: frozen
            │   │   ├── opening_loc: ∅
            │   │   ├── content_loc: (2,0)-(2,5) = "foo\\r"
            │   │   ├── closing_loc: ∅
            │   │   └── unescaped: "foo\r"
            │   ├── @ EmbeddedVariableNode (location: (2,5)-(2,10))
            │   │   ├── operator_loc: (2,5)-(2,6) = "#"
            │   │   └── variable:
            │   │       @ InstanceVariableReadNode (location: (2,6)-(2,10))
            │   │       └── name: :@bar
            │   └── @ StringNode (location: (2,10)-(3,0))
            │       ├── flags: frozen
            │       ├── opening_loc: ∅
            │       ├── content_loc: (2,10)-(3,0) = "\n"
            │       ├── closing_loc: ∅
            │       └── unescaped: "\n"
            └── closing_loc: (3,0)-(4,0) = "EOS\n"