@Contract("null -> null")
  @Nullable
  private static PsiReferenceExpression getAppendedExpression(PsiExpression expression) {
    PsiElement parent = expression;
    while (parent instanceof PsiParenthesizedExpression || parent instanceof PsiPolyadicExpression) {
      parent = parent.getParent();
    }
    if (!(parent instanceof PsiAssignmentExpression)) return null;
    return ObjectUtils.tryCast(PsiUtil.skipParenthesizedExprDown(((PsiAssignmentExpression)parent).getLExpression()),
                               PsiReferenceExpression.class);
  }
@Contract("null -> null")
  @Nullable
  private static PsiReferenceExpression getAppendedExpression(PsiExpression expression)