[Question] How to eliminate cartesian product for negation

Hello,

I have the following code :
```
class Foo extends Class {
Foo() {
not isAbstract()
and exists(Bar i | extendsOrImplements(i))
}
```

My understanding from the documentation (https://codeql.github.com/docs/writing-codeql-queries/troubleshooting-query-performance/#eliminate-cartesian-products) is that can lead to computing the cartesian product of the two sets, is it possible to improve the performance of this class?