That sounds like M-x dabbrev-expand which is bound to M-/ by default (and yeah, I love it). Though I do like the context sensitive completions that lsp pr

That sounds like M-x dabbrev-expand which is bound to M-/ by default (and yeah, I love it). Though I do like the context sensitive completions that lsp provides as well. They are particularly good for showing you structure members (since the language server knows the types).