"Uncaught SyntaxError: Identifier '__ddcInitCode' has already been declared"

[parlough]

When loading an embedded DartPad (for example on https://docs.flutter.dev/cookbook/lists/long-lists), which passes the code to the iframe and automatically runs the sample, I get this error in the console.

Uncaught SyntaxError: Identifier '__ddcInitCode' has already been declared, error: SyntaxError: Identifier '__ddcInitCode' has already been declared

\cc @biggs0125

[biggs0125]

I've confirmed that the SyntaxError no longer occurs when visiting the above page.

Thanks for raising this @parlough!