Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires vimeo/psalm ^5.26.1 -> satisfiable by vimeo/psalm[5.26.1, 5.x-dev]. - Root composer.json requires infection/infection ^0.29.8 -> satisfiable by infection/infection[0.29.8, 0.29.x-dev]. - Conclusion: don't install nikic/php-parser v5.3.1 (conflict analysis result) - phpunit/phpunit[9.6.21, ..., 9.6.x-dev] require phpunit/php-code-coverage ^9.2.32 -> satisfiable by phpunit/php-code-coverage[9.2.32, 9.2.x-dev]. - Conclusion: don't install phpunit/php-code-coverage[9.2.32] | install nikic/php-parser[v5.3.1] (conflict analysis result) - Root composer.json requires phpunit/phpunit ^9.6.21 -> satisfiable by phpunit/phpunit[9.6.21, 9.6.x-dev]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.