Scala 3.8 macros using `Option.orNull` cannot be consumed on Scala 3.9

[WojciechMazur]

Based on the OpenCB failure in sangria-graphql/sangria - build logs

Compiler version

3.9.0-RC4

Most likely caused by #25733

Minimized code

// macro.scala
//> using scala 3.8.4

package sangria

import scala.quoted.*

object Macros:
  inline def useOrNull[T](inline o: Option[T]): T =
    ${ useOrNullImpl('o) }

  def useOrNullImpl[T: Type](o: Expr[Option[T]])(using Quotes): Expr[T] =
    '{ $o.orNull.asInstanceOf[T] }

// test.scala 
//> using jar sangria-macros.jar
//> using scala 3.9.0-RC4

object AstVisitor:
  def visit(o: Option[String]): String = sangria.Macros.useOrNull(o)

Reproduction steps:

scala package macro.scala --library -o sangria-macros.jar -f
scala compile test.scala 

Output

Compiling project (Scala 3.9.0-RC4, JVM (25))
[error] ./sangria.scala:5:42
[error] illegal access to protected method orNull in class Option from object AstVisitor
[error]   def visit(o: Option[String]): String = sangria.Macros.useOrNull(o)
[error]                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^

Expectation

Macro produced with older version of Scala should still be valid when used on newer compiler due to backward compatibility guarantees

[Gedochao]

cc @olhotak

[SethTisue]

Should this be milestoned...?

[olhotak]

The following comment from @sjrd says that the change to protected preserves TASTy compatibility:
#25733 (comment)

Since macros process TASTy, does that mean that macros should not check accessibility (at least in cases like this one)?

[sjrd]

I guess I was wrong, then. We should probably use an @binaryAPI private anyway wouldn't we?