Change assert into if statement

[Nashenas88]

Fixes #63765

I'm not sure if this is actually what should be done. It's not clear to me why the output of the Paren expression would be modified and why that would make sense.

If this does make sense, I'd like to add comments explaining what's actually occurring here so it's clear for the next person who has to update this area.

[Nashenas88]

This should also have a test associated with it. Not sure on the exact code in polonius-engine that causes this case to come up. I was only able to narrow it down to the Func generic param in:

    fn filter_with<'leap, Tuple: Ord, Func: Fn(&Tuple) -> (Key, Val)>(
        &'leap self,
        key_func: Func,
    ) -> filter_with::FilterWith<'leap, Key, Val, Tuple, Func>
    where
        Key: 'leap,
        Val: 'leap;

(from datafrog)

[Nashenas88]

This now works in the nightly compiler without my change. Going to close this PR.

[Nashenas88]

@GuillaumeGomez @Mark-Simulacrum can this be reopened? I shouldn't have closed this.

[Mark-Simulacrum]

You'll need to open a new PR I believe - GitHub doesn't allow reopening pull requests where the underlying branch changed in-between.

[GuillaumeGomez]

@Mark-Simulacrum TIL haha