Theme_My_Login_Form::get_fields()

public function get_fields() {
    $priorities    = array();
    $sorted_fields = array();

    // Prioritize the fields
    foreach ( $this->fields as $field ) {
        $priority = $field->get_priority();
        if ( ! isset( $priorities[ $priority ] ) ) {
            $priorities[ $priority ] = array();
        }
        $priorities[ $priority ][] = $field;
    }

    ksort( $priorities );

    // Sort the fields
    foreach ( $priorities as $priority => $fields ) {
        foreach ( $fields as $field ) {
            $sorted_fields[] = $field;
        }
    }
    unset( $priorities );

    return $sorted_fields;
}

View src/includes/class-theme-my-login-form.php, line 317 on GitHub