The new implementation port from [esbuild](df815ac27b/internal/js_parser/js_parser_lower.go (L355-L467)), before from `Babel`.
Babel's transform implementation for the async method is incorrect because the async method should return a rejecting promise when it throws an error. Everything is good if the errors are thrown in the async method body, but the following case will throw an error in the parameters which causes the whole program crushed not a rejecting promise. So we should move the parameters to the inner generator function when the parameters could throw an error.
Input:
```js
class Cls {
// ReferenceError: Cannot access 'b' before initialization
async method(a = b, b = 0) {}
}
```
Before output
```js
class Cls {
method(a = b, b = 0) {
return babelHelpers.asyncToGenerator(function* () {})();
}
}
```
After output:
```js
class Cls {
method() {
// ReferenceError: Cannot access 'b' before initialization
return babelHelpers.asyncToGenerator(function* (a = b, b = 0) {}).apply(this, arguments);
}
}
```
No override tests because Babel doesn't cover this case.
06ccb51fae