IllegalAccessError when accessing a Java protected member via a self-type

[scabug]

This is with Scala 2.8.0.RC3

Steps to reproduce:

in p/Base.java

package p;
public class Base {
  protected void test() { }
}

in test.scala

trait Ext {
  this: p.Base =>
  def run = test // Access Java protected member here
}

object Test {
  def main(args: Array[String]) {
    val s = new p.Base with Ext
    s.run
  }
}

compile & run

$$ javac p/Base.java
$$ scalac test.scala
$$ scala Test
java.lang.IllegalAccessError: tried to access method p.Base.test()V from class Ext$$class
	at Ext$$class.run(test.scala:3)
	at Test$$$$anon$$1.run(test.scala:8)
	at Test$$.main(test.scala:9)
	at Test.main(test.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at scala.tools.nsc.util.ScalaClassLoader$$$$anonfun$$run$$1.apply(ScalaClassLoader.scala:81)
	at scala.tools.nsc.util.ScalaClassLoader$$class.asContext(ScalaClassLoader.scala:24)
	at scala.tools.nsc.util.ScalaClassLoader$$URLClassLoader.asContext(ScalaClassLoader.scala:86)
	at scala.tools.nsc.util.ScalaClassLoader$$class.run(ScalaClassLoader.scala:81)
	at scala.tools.nsc.util.ScalaClassLoader$$URLClassLoader.run(ScalaClassLoader.scala:86)
	at scala.tools.nsc.MainGenericRunner$$.main(MainGenericRunner.scala:78)
	at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

If the base class is written in Scala, this doesn't happen (because the protected method is compiled as public).

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-3564?orig=1
Reporter: Ben Lings (lings)

[scabug]

@paulp said:
Duplicate of #2296.

[SethTisue]

this is broken in 2.11.11 and 2.12.2 (thx @RomanIakovlev for calling attention to it)

[unkarjedy]

caught the error at runtime in 2.12.7

[unkarjedy]

Ok, I managed to prepare a minimal reproducible example even with scala 2.13.3
(example project: illegal_access_to_protected_member.zip)

It looks like there is no any error when both scala class and base java classes are in the same scope main (run Main.scala).
But the error arises if you place scala classes in test scope and.

Exception in thread "main" java.lang.IllegalAccessError: class test_package.MyTrait tried to access protected field main_package.BaseJavaClass.baseField (test_package.MyTrait and main_package.BaseJavaClass are in unnamed module of loader 'app')
	at test_package.MyTrait.bar(MainFromTests.scala:18)
	at test_package.MyTrait.bar$(MainFromTests.scala:18)
	at test_package.MyClass.bar(MainFromTests.scala:8)
	at test_package.MyClass.foo(MainFromTests.scala:12)
	at test_package.MainFromTests$.main(MainFromTests.scala:5)
	at test_package.MainFromTests.main(MainFromTests.scala)

[unkarjedy]

Encountered it once again with 2.13.2.
This time base class was from a library jar

[som-snytt]

Possibly related to #12249