New rule: Forbid nesting scope functions

[BraisGabin]

Expected Behavior of the rule

non-compilant:

a?.let {
  a.also {
    // ...
  }
}

A rule to forbid nesting scope functions.

Context

Extracted from Kotlin Scope functions (emphasis mine):

Although the scope functions are a way of making the code more concise, avoid overusing them: it can decrease your code readability and lead to errors. Avoid nesting scope functions and be careful when chaining them: it's easy to get confused about the current context object and the value of this or it.

[marschwar]

I like it but this will be very controversial and hard to turn on in any code base.
Maybe We should already think about config parameters such as depth of nesting and allowing functions references.

[BraisGabin]

It should not be that controversial. The official documentation say that.

And about adopting the rule, I don't think it should be hard. You enable it, you recreate the baseline and you are good to go. Any new nesting scope function will be reported. How to handle the ones in the baseline is another thing.

I would vote to launch the rule without any nesting paramater. If there are complains and good reasons to add it we can add it later. But, right now, I can't think a good reason to allow 2 nesting scope functions and forbid 3.

[atulgpt]

Hi @BraisGabin IG NestedScopeFunctions does the same. It was fixed by #4780

[cortinico]

Yup closing #4788