private List<PsiClass> calculateInterfacesSupported() {
    final List<PsiClass> out = new ArrayList<>();
    final PsiClass[] supers = sourceClass.getSupers();
    for (PsiClass superClass : supers) {
      if (!superClass.isInterface()) {
        continue;
      }
      final PsiMethod[] superclassMethods = superClass.getMethods();
      if (superclassMethods.length == 0) {
        continue;
      }
      boolean allMethodsCovered = true;

      for (PsiMethod method : superclassMethods) {
        boolean isCovered = false;
        for (PsiMethod movedMethod : methods) {
          if (isSuperMethod(method, movedMethod)) {
            isCovered = true;
            break;
          }
        }
        if (!isCovered) {
          allMethodsCovered = false;
          break;
        }
      }
      if (allMethodsCovered) {
        out.add(superClass);
      }
    }
    final Project project = sourceClass.getProject();
    final PsiManager manager = sourceClass.getManager();
    final GlobalSearchScope scope = GlobalSearchScope.allScope(project);
    if (usesDefaultSerialization(sourceClass)) {
      final PsiClass serializable = JavaPsiFacade.getInstance(manager.getProject()).findClass("java.io.Serializable", scope);
      out.add(serializable);
    }
    if (usesDefaultClone(sourceClass)) {
      final PsiClass cloneable = JavaPsiFacade.getInstance(manager.getProject()).findClass("java.lang.Cloneable", scope);
      out.add(cloneable);
    }
    return out;
  }
private List<PsiClass> calculateInterfacesSupported()