对我来说，这发生在一个类函数中。

在PHP 5.3及以上版本中，$this::$默认值工作正常;当我把代码交换到一个服务器上时，不管出于什么原因，这个服务器的版本号更低，它抛出了这个错误。

解决方案，在我的情况下，是使用关键字self而不是$this:

Self::$defaults工作得很好。

它是双冒号操作符::(参见解析器令牌列表)。

从维基百科:

In PHP, the scope resolution operator is also called Paamayim Nekudotayim (Hebrew: פעמיים נקודתיים‎), which means “double colon” in Hebrew. The name "Paamayim Nekudotayim" was introduced in the Israeli-developed Zend Engine 0.5 used in PHP 3. Although it has been confusing to many developers who do not speak Hebrew, it is still being used in PHP 5, as in this sample error message: $ php -r :: Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM As of PHP 5.4, error messages concerning the scope resolution operator still include this name, but have clarified its meaning somewhat: $ php -r :: Parse error: syntax error, unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM)

来自PHP官方文档:

The Scope Resolution Operator (also called Paamayim Nekudotayim) or in simpler terms, the double colon, is a token that allows access to static, constant, and overridden properties or methods of a class. When referencing these items from outside the class definition, use the name of the class. As of PHP 5.3.0, it's possible to reference the class using a variable. The variable's value can not be a keyword (e.g. self, parent and static). Paamayim Nekudotayim would, at first, seem like a strange choice for naming a double-colon. However, while writing the Zend Engine 0.5 (which powers PHP 3), that's what the Zend team decided to call it. It actually does mean double-colon - in Hebrew!

对我来说，这发生在一个类函数中。

在PHP 5.3及以上版本中，$this::$默认值工作正常;当我把代码交换到一个服务器上时，不管出于什么原因，这个服务器的版本号更低，它抛出了这个错误。

解决方案，在我的情况下，是使用关键字self而不是$this:

Self::$defaults工作得很好。

希伯来语是"双冒号"的意思。

当你在PHP中对empty()函数应用常量时，也会出现这种情况:

if (!empty(SOME_CONSTANT)) {

}

那是我的案子。我用这个方法解决了这个问题:

$string = SOME_CONSTANT;
if (!empty($string)) {

}