Add quick fix to add .nn

[SuperCl4sh]

An extension to #23461 that adds a quick fix to add a .nn. For example, if the code were

val t: String | Null = ???
val s: String = t

the quick fix would transform the code to

val t: String | Null = ???
val s: String = t.nn

The code is WIP (I've put some ugly workarounds to get it to work). Right now, it adds brackets whenever the root node is an Apply. This is needed for infix functions (both those with ApplyKind InfixTuple and those that are written as such in the source code, such as + which is desugared to an ApplyKind Regular I think), but there may be other edge cases where brackets are needed. I've discussed these edges cases a bit with @olhotak and @HarrisL2, but it's possible that we've missed some (or I've forgotten to add them).

[HarrisL2]

cc @noti0na1

[SuperCl4sh]

All the issues should be resolved now.

[noti0na1]

I was on vocation in last few weeks. I will review it soon.

[noti0na1]

LGTM

[tgodzik]

Tried backposting the PR, but got:

[info] compiling 92 Scala sources and 25 Java sources to /Users/tgodzik/Documents/scala3/out/bootstrap/scala3-library-bootstrapped/scala-3.3.8-RC1-bin-SNAPSHOT-nonbootstrapped/classes ...
[error] -- Error: /Users/tgodzik/Documents/scala3/library/src/scala/IArray.scala:259:85 
[error] 259 |    def ++[U >: T: ClassTag](suffix: IArray[U]): IArray[U] = genericArrayOps(arr) ++ suffix.toSeq
[error]     |                                                                                     ^
[error]     |?{ toSeq: <?> } is not a value type, cannot be used in union ?{ toSeq: <?> } | Null
[error] -- Error: /Users/tgodzik/Documents/scala3/library/src/scala/IArray.scala:272:77 
[error] 272 |    def diff[U >: T](that: IArray[U]): IArray[T] = genericArrayOps(arr).diff(that.toSeq)
[error]     |                                                                             ^
[error]     |?{ toSeq: <?> } is not a value type, cannot be used in union ?{ toSeq: <?> } | Null
[error] -- Error: /Users/tgodzik/Documents/scala3/library/src/scala/IArray.scala:298:77 
[error] 298 |    def search[U >: T](elem: U)(using Ordering[U]): Searching.SearchResult = arr.toSeq.search(elem)
[error]     |                                                                             ^
[error]     |?{ toSeq: <?> } is not a value type, cannot be used in union ?{ toSeq: <?> } | Null
[error] -- Error: /Users/tgodzik/Documents/scala3/library/src/scala/IArray.scala:299:97 
[error] 299 |    def search[U >: T](elem: U, from: Int, to: Int)(using Ordering[U]): Searching.SearchResult = arr.toSeq.search(elem, from, to)

Most likely due to some other changes that were not backported. With experimental stuff like this we should be fine.

[SuperCl4sh]

That's quite weird. We had that issue before pushing 6c2147d, but it shouldn't be an issue anymore because we only OrNull a type when we know it's a value type (https://github.com/scala/scala3/pull/23598/files#diff-e054695755ff26925ae51361df0f7cd4940bc1fd7ceb658023d0dc38c18178c3R305-R306).
Can you send the git log (via a text file or pastebin) so I can take a closer look at the commits? (or you can push your code and send the link, whichever is easier for you)

[tgodzik]

ach, that might be it. I didn't realize it was a temporary issue. Ideally we would squash in those situations. I will try and backport it again next week.