php - Why can I use a string literal as a class in php7?

itemprop="text">

Consider the following
code:

class foo {

            static $bar =
            'baz';
}
var_dump('foo'::$bar);

/>

It throws an error in PHP5 (as
expected):

Parse error: syntax error, unexpected '::'
(T_PAAMAYIM_NEKUDOTAYIM) in [...][...] on line
4

/>

But it works without an issue in PHP7 and
outputs:

string(3)
            "baz"

/>

Is that intentional or a bug?

Answer

I think it's because they rewrote stuff
regarding evaluation.

like the
following is not possible in PHP5 but in PHP
7:

echo (new
            X)->toString();

Same
would go for

echo
            ('X')::$bar

See
href="http://php.net/manual/de/migration70.incompatible.php#migration70.incompatible.variable-handling.indirect"
rel="nofollow noreferrer">Changes to the handling of indirect variables, properties,
and methods

This is mainly about the
left-to-right evaluation but it also affects the evaluation in
general.

More information can be found on href="https://wiki.php.net/rfc/uniform_variable_syntax" rel="nofollow noreferrer">PHP
RFC: Uniform Variable Syntax (Status: implemented) - Thanks to href="https://stackoverflow.com/questions/38468161/why-can-i-use-a-string-literal-as-a-class-in-php7/38468719#comment64343727_38468161">Nikic:

This RFC proposes the introduction of an internally consistent and

complete variable syntax. To achieve this goal the semantics of some
rarely
used variable-variable constructions need to be
changed.