An interesting point. But this could be mitigated in a fairly obvious way by requiring an equivalent of "await" that is basically an identity transform for future-returning function calls (i.e. if a call is returning a future, you must always either explicitly indicate that you're awaiting it, or else explicitly indicate that you want the raw future - a naked call is an error).

That wouldn't solve the problem at all--at best I'm getting a marginally clearer error message. It doesn't help me (the programmer) remember (before runtime) that my expression is evaluating to an async function and not a sync function. Whether I get the runtime error, "invalid call to async function" or "future has no property 'status_code'" is of little consequence.