dillon1000/react

[typer] Be more conservative with function type inference

It's not safe to infer types of arguments and return values because Javascript 
is so polymorphic. Instead just infer the type of the callee for non methods. 

Interestingly, even this is not conservative enough for JavaScript because Proxy 
can also be callable. But I think for our use cases we will treat Proxy and 
Functions similarly (they're all just objects) so it's ok.