[php] How do I correct this Illegal String Offset?

I am receiving this error "Warning: Illegal string offset 'type' in /home/mysite/public_html/wp-content/themes/evento/lib/php/extra.class.php on line 32"

and I realized this section of code in the file is wrong, however I'm not that great in PHP yet and I am wondering if someone can help me re-write this section to eliminate the error. Thanks! (the error starts on line 32 which is the beginning of the if statement below)

Here is the code:

/* new version */
    function get_attachment_struct( $inputs ){
        $attach = array();

    if( $inputs['type'] == 'attach' ){ 
            $name = $inputs['name'];
            $attach = array(
                0 => array(
                    'name' => $name,
                    'type' => 'text',
                    'label' =>  'Attachment URL',
                    'lvisible' => false,
                    'upload' => true,
                ),
                1 => array(
                    'name' => $name .'_id',
                    'type' => 'hidden',
                    'upload' => true
                ),
            );

            if( isset( $inputs[ 'classes' ] ) ){
                $attach[0]['classes'] = $inputs[ 'classes' ];
                $attach[1]['classes'] = $inputs[ 'classes' ] . '_id';
            }
        }
        return $attach;
    }

    /* new version */

I get the same error in WP when I use php ver 7.1.6 - just take your php version back to 7.0.20 and the error will disappear.

if(isset($rule["type"]) && ($rule["type"] == "radio") || ($rule["type"] == "checkbox") )
{
    if(!isset($data[$field]))
        $data[$field]="";
}