Oh, and I should probably say that I don’t know which HLS version was the one that worked, because although I have '(lsp-haskell-server-path "haskell-language-server-wrapper-2.4.0.0") in my .emacs configuration file, lsp-mode doesn’t actually seem to honor that. It just seems to load whatever version of HLS has been set as default in ghcup. I’ve also tried 2.5 and 2.6 and neither of them seem to support the missing features either. It’s possible that when they worked I was using a really old version of HLS, like 1.7, but I’ve deleted it now to free up disk space for the newer ones, so I can’t confirm …