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    <h3>Editing: TraversableContainsOnly.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);
/*
 * This file is part of PHPUnit.
 *
 * (c) Sebastian Bergmann &lt;sebastian@phpunit.de&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace PHPUnit\Framework\Constraint;

use PHPUnit\Framework\Exception;
use PHPUnit\Framework\ExpectationFailedException;
use SebastianBergmann\RecursionContext\InvalidArgumentException;
use Traversable;

/**
 * @no-named-arguments Parameter names are not covered by the backward compatibility promise for PHPUnit
 */
final class TraversableContainsOnly extends Constraint
{
    /**
     * @var Constraint
     */
    private $constraint;

    /**
     * @var string
     */
    private $type;

    /**
     * @throws Exception
     */
    public function __construct(string $type, bool $isNativeType = true)
    {
        if ($isNativeType) {
            $this-&gt;constraint = new IsType($type);
        } else {
            $this-&gt;constraint = new IsInstanceOf(
                $type,
            );
        }

        $this-&gt;type = $type;
    }

    /**
     * Evaluates the constraint for parameter $other.
     *
     * If $returnResult is set to false (the default), an exception is thrown
     * in case of a failure. null is returned otherwise.
     *
     * If $returnResult is true, the result of the evaluation is returned as
     * a boolean value instead: true in case of success, false in case of a
     * failure.
     *
     * @param mixed|Traversable $other
     *
     * @throws ExpectationFailedException
     * @throws InvalidArgumentException
     */
    public function evaluate($other, string $description = '', bool $returnResult = false): ?bool
    {
        $success = true;

        foreach ($other as $item) {
            if (!$this-&gt;constraint-&gt;evaluate($item, '', true)) {
                $success = false;

                break;
            }
        }

        if ($returnResult) {
            return $success;
        }

        if (!$success) {
            $this-&gt;fail($other, $description);
        }

        return null;
    }

    /**
     * Returns a string representation of the constraint.
     */
    public function toString(): string
    {
        return 'contains only values of type &quot;' . $this-&gt;type . '&quot;';
    }
}
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