PHP closure bindings... yeah, I know...

binding-test.php

<?php

// Require composer autoloader after installing superclosure 2.0.
require '/vendor/autoload.php';

class ClosureCreator
{
    public function getClosures()
    {
        $f1 = function () {};
        $f2 = static function () {};
        $f3 = function () {}; $f3 = $f3->bindTo(null);
        $f4 = function () {}; $f4 = $f4->bindTo(null, null);

        return [$f1, $f2, $f3, $f4];
    }
}

// Set up array of closure tests cases.
$closures = (new ClosureCreator)->getClosures();
$f0 = function () {};
array_unshift($closures, $f0);

// Analyze each closure for their binding, scope, and staticness.
$analyzer = new \SuperClosure\Analyzer\AstAnalyzer();
foreach ($closures as $i => $closure) {
    $data = $analyzer->analyze($closure);
    echo "f{$i}:\n";
    echo "\tBinding: " . (is_object($data['binding']) ? get_class($data['binding']) : 'NULL') . "\n";
    echo "\tScope: " . ($data['scope'] ?: 'NULL') . "\n";
    echo "\tStatic: " . ($data['isStatic'] ? 'YES' : 'NO') . "\n";
}

output.txt

f0:
        Binding: NULL
        Scope: NULL
        Static: NO
f1:
        Binding: ClosureCreator
        Scope: ClosureCreator
        Static: NO
f2:
        Binding: NULL
        Scope: ClosureCreator
        Static: YES
f3:
        Binding: NULL
        Scope: ClosureCreator
        Static: YES
f4:
        Binding: NULL
        Scope: NULL
        Static: NO