The following code:

public class CyclicScoping {
  class Inner1 extends Inner2 {}
  class Inner2 {
    class Inner3 extends Inner1 {}
  }
}

causes

java.lang.ClassCastException: sun.tools.tree.LocalField
        at sun.tools.javac.SourceField.createArgumentFields(SourceField.java)
        at sun.tools.javac.SourceField.resolveTypeStructure(SourceField.java)
        at sun.tools.javac.SourceClass.resolveTypeStructure(SourceClass.java)
        at sun.tools.javac.SourceField.resolveTypeStructure(SourceField.java)
        at sun.tools.javac.SourceClass.resolveTypeStructure(SourceClass.java)
        at sun.tools.javac.SourceClass.basicCheck(SourceClass.java)
        at sun.tools.java.ClassDefinition.basicCheck(ClassDefinition.java)
        at sun.tools.javac.SourceClass.basicCheck(SourceClass.java)
        at sun.tools.java.ClassDeclaration.getClassDefinition(ClassDeclaration.java)
        at sun.tools.javac.Main.compile(Main.java)
        at sun.tools.javac.Main.main(Main.java)
error: An exception has occurred in the compiler; please file a bug report (###@###.###).
1 error