javac emits duplicate entries in the constant pool and PermittedSubclasses attribute for the following example.

I don't think the JVMS disallows this, but the duplication is surprising to me and looks accidental.

This only reproduces with -Xdoclint:html,syntax

public class T {
  private enum E {
    INSTANCE {
      /** foo {@link E} */
      void f() {}
    };

    void f() {}
  }
}

javac -fullversion
javac full version "25-ea+8-843"

javac -Xdoclint:html,syntax T.java && javap -v -p 'T$E'
...
PermittedSubclasses:
  T$E$1
  T$E$1
InnerClasses:
  private static #52= #1 of #47; // E=class T$E of class T
  final #26; // class T$E$1
  final #50; // class T$E$1