Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires ghostwriter/coding-standard dev-main -> satisfiable by ghostwriter/coding-standard[dev-main]. - ghostwriter/coding-standard dev-main requires vimeo/psalm ^6.0 || dev-master as 6.0.999 -> found vimeo/psalm[dev-master, 6.x-dev (alias of dev-master)] but it does not match your minimum-stability. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.