On: Why Dart Types Are Optional and Unsound

[jashkenas]

    > Correctness is easier to achieve for a VM that doesn't
    > rely on static soundness guarantees, because you don't
    > need the complexity of bytecode verification.

I don't follow. You only need to verify bytecode if a), you have bytecode in the first place, and b), you assume the existence of a hostile compiler or other external bytecode source. Neither of these apply to Dart.

[roestava → jashkenas]

Maybe with static typing and bytecodes the author was meaning lower level and hence riskier stuff. Not that Dart was lower level.

By being higher level Dart can work from a subset, keeping the surface area smaller as a result.