[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?

Start with the linked CodeQL query-performance troubleshooting documentation and the provided predicate expression. No source file or test is named, so inspect how negation and exists are evaluated in this query context. Done means providing a supported explanation or documentation guidance for avoiding the reported cartesian-product cost.

Rédigé par le modèle d'indexation à partir du texte de l'issue.