[question?] counterintuitive class method behaviour

When I write a query like this:
```codeql
class Meow extends Struct {
Field f;
Meow() {
f.getDeclaringType() = this
}
Field getField() { result = f }
}

from Meow m
select m, m.getField(), m.getField()
```
My mental model of this is: "`Meow` is essentially a (struct, struct's field) tuple. `from Meow m` will select all of those tuples. For each of those , `select m, m.getField(), m.getField()` will print their contents."

But that is actually not what happens, because you get results like this:
```
| m | col1 | col2 |
+-----------------------------------+-----------------------------------------------------+-----------------------------------------------------+
// [snip]
| port_io_ops | f_inb | f_outb |
// [snip]
```
Which means that the first `m.getField()` and the second `m.getField()` are operating on different `Meow` objects.

I've been debugging a bug in my query for hours now only to realize that this is what happens. Is this really intended? I read through a non-trivial amount of documentation and did not realize this, I feel like my whole mental model of how codeql works is shattering :S

(If it is really intended, could the documentation be updated to point this out more clearly?)

Commencez par la requête et la sortie CodeQL présentées dans l’issue, puis consultez la documentation consacrée aux méthodes de classe et à l’évaluation des prédicats. Confirmez le comportement attendu et identifiez la section pertinente de la documentation ; le travail est terminé lorsque le comportement est expliqué assez clairement pour combler la lacune signalée dans le modèle mental.

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