Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires psalm/plugin-phpunit ^0.19 -> satisfiable by psalm/plugin-phpunit[0.19.0]. - Conclusion: don't install phpunit/php-code-coverage 11.0.5 (conflict analysis result) - Conclusion: don't install phpunit/php-code-coverage 11.0.0 (conflict analysis result) - vimeo/psalm 5.26.1 conflicts with nikic/php-parser v4.17.0. - psalm/plugin-phpunit 0.19.0 requires vimeo/psalm dev-master || ^5@beta || ^5.0 -> satisfiable by vimeo/psalm[5.25.0, 5.26.0, 5.26.1]. - Conclusion: don't install vimeo/psalm 5.26.0 (conflict analysis result) - Conclusion: don't install vimeo/psalm 5.25.0 (conflict analysis result) - Root composer.json requires phpunit/phpunit ^11.0 -> satisfiable by phpunit/phpunit[11.0.0, ..., 11.3.6]. - vimeo/psalm 5.26.1 requires nikic/php-parser ^4.17 -> satisfiable by nikic/php-parser[v4.17.0, ..., v4.19.2]. - You can only install one version of a package, so only one of these can be installed: nikic/php-parser[v4.16.0, ..., v4.19.2, v5.0.0, ..., v5.2.0]. - phpunit/php-code-coverage 11.0.6 requires nikic/php-parser ^5.1.0 -> satisfiable by nikic/php-parser[v5.1.0, v5.2.0]. - Conclusion: install one of phpunit/php-code-coverage[11.0.0, 11.0.5, 11.0.6] (conflict analysis result) Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.