IncompatibleClassChangeError on getDeclaringClass

[scabug]

Executing this simple snippet of code:

object Test {
  def main(args: Array[String]): Unit = {
    val outter = new MyTest {
      val inner = new MyTest {
      }
    }
  }
}

class MyTest {
  println(s"${getClass.getName} - ${getClass.getDeclaringClass}")
}

Results in:

java.lang.IncompatibleClassChangeError: Test$ and Test$$anon$1$$anon$2 disagree on InnerClasses attribute
java.lang.IncompatibleClassChangeError: Test$ and Test$$anon$1$$anon$2 disagree on InnerClasses attribute
	at java.lang.Class.getDeclaringClass0(Native Method)
	at java.lang.Class.getDeclaringClass(Class.java:1101)

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-7994?orig=1
Reporter: Matt Hicks (darkfrog)
Affected Versions: 2.10.3
Attachments:

• Test2.scala (created on Nov 22, 2013 2:12:28 PM UTC, 220 bytes)

[scabug]

Matt Hicks (darkfrog) said:
How long does it take to get anyone to verify this bug?

[scabug]

@som-snytt said:
I can verify that I get the same result. So, about 32 minutes. I guess for pizza, that means it's free.

[scabug]

Matt Hicks (darkfrog) said:
I appreciate the follow-up but it's been nearly two weeks since I first reported it, so that's a pretty stale pizza. ;)

[SethTisue]

closing backend tickets which are likely stale; comment and/or reopen if you have evidence this is still applicable

[lrytz]

Fixed, the 2.12 backend got an onvehaul of InnerClass attribute computation. Let's verify the result is correct and add a regression test to https://github.com/scala/scala/tree/v2.13.0-M3/test/files/jvm/innerClassAttribute

[adriaanm]

@lrytz did this end up getting verified as fixed?

[adriaanm]

It doesn't crash, at least. I'll leave it open in case null was not the expected result for the declaring class..

scala-2.12.7-bin-f2129b9/bin/scala ~/Library/Preferences/IdeaIC2018.2/scratches/scratch_7.scala
Main$$anon$1 - null
Main$$anon$1$$anon$2 - null

[jxnu-liguobin]

Empty seems wrong? I am ready to look at the issue, where are the relevant codes or files? thanks

[lrytz]

https://docs.oracle.com/en/java/javase/16/docs/api/java.base/java/lang/Class.html#getDeclaringClass() says

If the class or interface represented by this Class object is a member of another class, returns the Class object representing the class in which it was declared

The two anonymous classes are both not "member" classes, so null is the correct value.

https://github.com/scala/scala/blob/8a2cf63ee5bad8c8c054f76464de0e10226516a0/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala#L352-L353

@jxnu-liguobin you could add a test case, that would be welcome.

Just tested with Java, it does the same:

public class Test {
  public static void main(String[] args) {
    Object o = new MyTest() {
      Object i = new MyTest() { };
    };
  }
}

class MyTest {
  public MyTest() {
    System.out.println(this.getClass().getName());
    System.out.println(this.getClass().getDeclaringClass());
  }
}

Test$1
null
Test$1$1
null

[jxnu-liguobin]

@lrytz
ok, https://github.com/scala/scala/pull/9553/files, i have added scala test case