IssueTracker

There is a corner case in VirtualDispatchMethodArgumentPropagator.shouldActivateMethodStateGuardedByBounds() method.
In R8 4.0.54, the method is as follows:
    private boolean shouldActivateMethodStateGuardedByBounds(
        ClassTypeElement upperBound, DexProgramClass currentClass, DexProgramClass superClass) {
      ClassTypeElement classType =
          TypeElement.fromDexType(currentClass.getType(), maybeNull(), appView).asClassType();
      // When propagating argument information for interface methods downwards from an interface to
      // a non-interface we need to account for the parent classes of the current class.
      if (superClass.isInterface()
          && !currentClass.isInterface()
          && currentClass.getSuperType() != appView.dexItemFactory().objectType) {
        return classType.lessThanOrEqualUpToNullability(upperBound, appView);
      }
      return classType.equalUpToNullability(upperBound);
    }
But there is a corner case, i.e upperBound and classType point to the same class, while classType.equalUpToNullability(upperBound); return false. And the reason is that upperBound has more interfaces than classType because of some vertical optimization.
As a result, some virtual method will be thought not reachable and put into throw null in method's body.