ghc 8.10.4 was not found in the cache. It will be downloaded. If this is unexpected, please check if version 8.10.4 is pre-installed. The list of pre-installed versions is available here: https://help.github.com/en/actions/reference/software-installed-on-github-hosted-runners The above list follows a common haskell convention that the three latest major releases of ghc are commonly supported. If the list is outdated, please file an issue here: https://github.com/actions/virtual-environments by using the appropriate tool request template: https://github.com/actions/virtual-environments/issues/new/choose