I don't know Dart (yet...I am familiar with its spiritual ancestor GWT) but if it's possible to expose functions to javascript, couldn't the compiler reason abo

I don't know Dart (yet...I am familiar with its spiritual ancestor GWT) but if it's possible to expose functions to javascript, couldn't the compiler reason about those interfaces, treating incoming values as "dirty" (potentially null), and omit null checks if no external functions are exposed? For example, GWT lightly-abuses the 'native' keyword in Java to mark a method as using the FFI to raw javascript. That's a piece of information the compiler can leverage.