public boolean isAlwaysNull(boolean ignoreAssertions) {
      PsiExpression expression = PsiUtil.skipParenthesizedExprDown(getDereferencedExpression());
      return expression != null &&
             (ExpressionUtils.isNullLiteral(expression) || CommonDataflow.getDfType(expression, ignoreAssertions) == DfTypes.NULL);
    }
public boolean isAlwaysNull(boolean ignoreAssertions)