Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires psalm/plugin-phpunit ^0.19.0 -> satisfiable by psalm/plugin-phpunit[0.19.0]. - Conclusion: don't install nikic/php-parser v4.17.1 (conflict analysis result) - Conclusion: don't install nikic/php-parser v4.16.0 (conflict analysis result) - vimeo/psalm[5.14.1, ..., 5.21.1] require sebastian/diff ^4.0 || ^5.0 -> satisfiable by sebastian/diff[4.0.0, ..., 4.0.6, 5.0.0, ..., 5.1.1]. - You can only install one version of a package, so only one of these can be installed: sebastian/diff[4.0.0, ..., 4.0.6, 5.0.0, ..., 5.1.1, 6.0.0, 6.0.1, 6.0.2]. - Conclusion: don't install one of sebastian/diff[6.0.2], vimeo/psalm[5.14.0] (conflict analysis result) - Conclusion: install sebastian/diff 6.0.2 (conflict analysis result) - sebastian/diff[4.0.0, ..., 4.0.1] require php ^7.3 -> your php version (8.3.12) does not satisfy that requirement. - vimeo/psalm[5.0.0, ..., 5.13.1] require php ^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 -> your php version (8.3.12) does not satisfy that requirement. - Root composer.json requires phpunit/phpunit ^11.0.0 -> satisfiable by phpunit/phpunit[11.0.0, ..., 11.4.4]. - vimeo/psalm[5.22.1, ..., 5.26.1] conflict with nikic/php-parser v4.17.0. - Conclusion: install one of vimeo/psalm[5.14.0, ..., 5.22.0], nikic/php-parser[v4.16.0, v4.17.0, v4.17.1, v4.19.0] (conflict analysis result) - Conclusion: don't install vimeo/psalm[5.22.0] | install one of nikic/php-parser[v4.16.0, v4.17.1, v4.19.0] (conflict analysis result) - Conclusion: don't install nikic/php-parser v4.19.0 (conflict analysis result) - Root composer.json requires vimeo/psalm ^5.0.0 -> satisfiable by vimeo/psalm[5.0.0, ..., 5.26.1]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.