Your requirements could not be resolved to an installable set of packages. Problem 1 - vimeo/psalm[5.4.0, ..., 5.7.7] require nikic/php-parser ^4.13 -> found nikic/php-parser[v4.13.0, ..., v4.18.0] but it conflicts with your root composer.json require (^5.0.2). - vimeo/psalm[5.8.0, ..., 5.13.1] require nikic/php-parser ^4.14 -> found nikic/php-parser[v4.14.0, ..., v4.18.0] but it conflicts with your root composer.json require (^5.0.2). - vimeo/psalm[5.14.0, ..., 5.23.1] require nikic/php-parser ^4.16 -> found nikic/php-parser[v4.16.0, v4.17.0, v4.17.1, v4.18.0] but it conflicts with your root composer.json require (^5.0.2). - Root composer.json requires vimeo/psalm ^5.4.0 -> satisfiable by vimeo/psalm[5.4.0, ..., 5.23.1]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.