`@unroll` should work on `final class`es without needing a `final` on each method

[lihaoyi]

Compiler version

3.7.0-RC1

Minimized code

final class Foo{
  def bar(@scala.annotation.unroll x: Int = 0) = x + 1
}

Output

[44] [error] -- [E207] Declaration Error: /Users/lihaoyi/test/src/test.scala:2:35 -----------
[44] [error] 2 |  def bar(@scala.annotation.unroll x: Int = 0) = x + 1
[44] [error]   |                                   ^
[44] [error]   |                   Cannot unroll parameters of method bar: it is not final
[44] [error] one error found

Expectation

@unroll should be able to see that the enclosing Foo is a final class, and thus allow us to elide final modifiers on the def bar. It already recognizes enclosing objects as final, so recognizing enclosing final class and final case classes is a straightforward extension

[mbovel]

This issue was picked for the Scala Issue Spree of Monday, April 7th. @hamzaremmal, @jan-pieter and @olhotak will be working on it. If you have any insight into the issue or guidance on how to fix it, please leave it here.