Yes we had this already in 2017: https://help.nextcloud.com/t/php-error-narrowing-occurred-during-type-inference/24010/17
cd /var/cache/pacman/pkg #hopefully you ve not cleaned your pkg cache!!!
pacman -U php-fpm-7.3.12-1-x86_64.pkg.tar.xz php-7.3.12-1-x86_64.pkg.tar.xz php-gd-7.3.12-1-x86_64.pkg.tar.xz php-intl-7.3.12-1-x86_64.pkg.tar.xz php-imagick-3.4.4-4-x86_64.pkg.tar.xz php-imap-7.3.12-1-x86_64.pkg.tar.xz php-memcached-3.1.4-1-x86_64.pkg.tar.xz php-apache-7.3.12-1-x86_64.pkg.tar.xz php-apcu-5.1.18-1-x86_64.pkg.tar.xz