@Contract("null -> false")
      private static boolean isSupportedQualifier(PsiExpression qualifier) {
        if (qualifier instanceof PsiQualifiedExpression) return true;
        if (qualifier instanceof PsiReferenceExpression) {
          PsiExpression subQualifier = ((PsiReferenceExpression)qualifier).getQualifierExpression();
          return subQualifier == null || isSupportedQualifier(subQualifier);
        }
        return false;
      }
@Contract("null -> false")
      private static boolean isSupportedQualifier(PsiExpression qualifier)