I'm trying to assemble a hierarchy that looks something like:

mixin BottomMI {
  abstract internal Obj[] objs
}

mixin MiddleMI : BottomMI {
  Obj addObj(Obj obj) {
    objs.add(obj)
    return obj
  }
}

abstract class MiddleCL : MiddleMI {
  override internal Obj[] objs := [,]
  abstract Void doSomething()
}

class TopCL : MiddleCL {
  override Void doSomething() {
    echo("Doing something")
  }
}

However, when I try to use these classes (built into a pod by the standard build::BuildPod class - not that this seems to matter as putting all of the code listed here into a single file and running it behaves much the same, as does fansh) using code such as:

using bugquestionmark
class Test {
  Void main() {
    tc := TopCL()
    tc.doSomething()
    tc.addObj("ASD")
  }
}

I get the following:

~/bugquestionmark$ fan Test.fan 
Doing something
sys::Err: java.lang.IllegalAccessError: fan.bugquestionmark.TopCL.objs()Lfan/sys/List;
  bugquestionmark::MiddleMI$.addObj (Unknown:3)
  bugquestionmark::MiddleCL.addObj (MiddleClass.fan)
  Test_0::Test.main (/Users/martin/bugquestionmark/Test.fan:6)
  java.lang.reflect.Method.invoke (Method.java:597)
  fan.sys.Method.invoke (Method.java:536)
  fan.sys.Method$MethodFunc.callOn (Method.java:214)
  fan.sys.Method.callOn (Method.java:148)
  fanx.tools.Fan.callMain (Fan.java:137)
  fanx.tools.Fan.executeFile (Fan.java:88)
  fanx.tools.Fan.execute (Fan.java:34)
  fanx.tools.Fan.run (Fan.java:241)
  fanx.tools.Fan.main (Fan.java:279)

The error is obviously around visibility of the declared Obj[] (internal) but my understanding of internal is that other classes within the same pod should be able to see but not outside of the pod - criteria which are met by this sample.

Thoughts?

Martin

Promoted to ticket #949 and assigned to brian

Its definitely a bug somewhere in how the class is overriding the mixin field.

Renamed from Bug or PEBKAC? to IllegalAccess in mixin field override

I narrowed down the problem a little more. It's an issue with making the objs slot internal. Remove the internal keyword from the slot and its override, and the code works normally.

mixin Collection 
{
  abstract internal Obj[] objs
  Obj add(Obj obj) 
  {
    objs.add(obj)
    return obj
  }
}

class ListCollection : Collection
{
  override internal Obj[] objs := [,]
}

class Main 
{
  Void main() 
  {
    list := ListCollection()
    list.add("ASD")
  }
}