fix: Fixes destructuring signal with await bug

[ngtr6788]

Fixes #9686 and #9312 and #9982. Because I can't find a place to determine if an expression is asynchronous, and I can't find a builder for async/await, I ended up building it. Hopefully it's good enough, but comments and feedback and advice is most certainly welcome, because I could be wrong :)

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[dummdidumm]

Could you briefly explain why there are multiple test cases for this? Can't they be handled in one test case?

Apart from that, I think this is the most sensible solution, can't think of other good approaches. One thing we possibly could do as a performance optimization is to traverse upwards to the closest function boundary first and check whether or not it's async. Not sure if the additional code is worth the possibly tiny savings we get from it.

[ngtr6788]

Could you briefly explain why there are multiple test cases for this? Can't they be handled in one test case?

Come to think of it now, you're right. I can just put it in one test case

One thing we possibly could do as a performance optimization is to traverse upwards to the closest function boundary first and check whether or not it's async. Not sure if the additional code is worth the possibly tiny savings we get from it.

Can you elaborate on what you mean by "closest function boundary"? I didn't quite get it :(

[dummdidumm]

Can you elaborate on what you mean by "closest function boundary"?

await can only be used in functions marked with the async keyword, so we could first traverse upwards to the closest function boundary and check if it has the async keyword. If not, then we know that there can't be an await inside the expression.

function x() { // the closest function boundary; no async modifier -> can't have await inside expression
  let { .. } = { .. }; // the expression we're checking
}

[dummdidumm]

Thank you!