Description:
------------
Since PHP 5.4 a closure can be bound to a object of a class to work like a method.
Since PHP 5.5 class name can be fetched with special syntax SomeClass::class, like a pseudo-constant with name 'class'.

This second feature does not work in a lambda, writen outside of a class. It cause syntax error.

Test script in a sandbox: http://3v4l.org/XO0bZ

May be, related with #66622 ?

Test script:
---------------
<?php
class A {
    const BAZ = 37;

    public static function f() {
        return static function () {
            var_dump(static::BAZ);
            var_dump(static::class);
        };
    }
}

$f = A::f();
$f();

$g = $f->bindTo(null, A::class);
$g();

$foo = static function () {
    var_dump(static::BAZ);
    var_dump(static::class);    // line 21 is here
};

$bar = $foo->bindTo(null, A::class);
$bar();

Expected result:
----------------
int(37)
string(1) "A"
int(37)
string(1) "A"
int(37)
string(1) "A"


Actual result:
--------------
Fatal error: Cannot access static::class when no class scope is active in ... on line 21