At the moment, `forall` is a keyword at the type level but an identifier at the term level: ```haskell forall = undefined -- accepted by GHC today ``` GHC Proposal [#281](https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0281-visible-forall.rst) makes `forall` a keyword at both levels. Since this is a breaking change, the first step was to add a warning (see #20609). This was done in dfc4093c. ``` Main.hs:5:1: warning: [-Wforall-identifier] The use of ‘forall’ as an identifier will become an error in a future GHC release. Suggested fix: Consider using another name, such as ‘forAll’, ‘for_all’, or ‘forall_’. ``` The warning `-Wforall-identifier` has been available for three releases (GHC 9.4, 9.6, and the soon-to-be-released 9.8), meaning we can complete the transition in GHC 9.10. Now `forall` can become a proper keyword and the warning should become a deprecated no-op.