private static @Nullable PsiElement resolveExpression(@NotNull PsiElement expr, @NotNull PsiAssignmentExpression parentExpr) {
    PsiElement result = null;
    if (expr instanceof PsiReferenceExpression) {
      result = ((PsiReferenceExpression)expr).resolve();
    } else {
      final PsiExpression lExpr = PsiUtil.deparenthesizeExpression(parentExpr.getLExpression());
      if (lExpr instanceof PsiReferenceExpression) {
        result = ((PsiReferenceExpression)lExpr).resolve();
      }
    }
    return result;
  }
private static @Nullable PsiElement resolveExpression(@NotNull PsiElement expr, @NotNull PsiAssignmentExpression parentExpr)