Ben, Matthew I believe that 'master' fails validate. See Trac #16346. The question is: how did it get past CI? The bug would only show up if -dcore-lint was on for libraries. Simon -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20190221/df8ed3f2/attachment.html>