Re: queryId constant squashing does not support prepared statements

> > On Thu, May 22, 2025 at 10:23:31PM GMT, Sami Imseih wrote:
> > > This does not get squashed:
> > > Q: select where 2 in (1, 4) and
> > > 1 in (5, cast(7 as int), 6, (cast(8 as int)), 9, 10, (cast(8 as text))::int);
> > > R: select where $1 in ($2 /*, ... */) and
> > > $3 in ($4, cast($5 as int), $6, (cast($7 as int)), $8, $9, (cast($10 as text))::int)
> >
> > This is interesting actually. This is the behavior on HEAD, and I don't get why
> > the first list with the casts does not get squashed, while the second one does.
> > I will check IsSquashableConst tomorrow unless Dmitry gets to it first.
>
> IsSquashableConst has intentionally a limited set of test for
> "constantness", in particular it does not recurse. The case above
>
>     (cast(8 as text))::int
>
> features two CoerceViaIO expressions one inside another, hence
> IsSquashableConst returns false.


Should we be doing something like this? to unwrap RelabelType or
CoerceViaIO until we have a different type of node to check
for later on. We can guard the loop and break out after x amount
of times as well. At minimum, we should try to unwrap at least
2 times for some of the common real-world scenarios.

What do you think?

```
while (IsA(element, RelabelType) || IsA(element, CoerceViaIO))
{
       if (IsA(element, RelabelType))
           element = (Node *) ((RelabelType *) element)->arg;
       else if (IsA(element, CoerceViaIO))
            element = (Node *) ((CoerceViaIO *) element)->arg;
}
```

--
Sami