If you open up simdjson.h (I tried with two version of it) with didOpen+didClose, clangd will eat memory until crash. I tried with an editor in beta and in vscode, both act the same. All you need to do is open the file, close it, wait ~5min for clangd to eat 32GB of ram. I’m on linux 6.6.8 using clangd 16.0.6
https://raw.githubusercontent.com/simdjson/simdjson/master/singleheader/simdjson.h
I’m fairly sure this is the same issue as clangd uses up all the memory (~90GB) for miniaudio.h · Issue #70945 · llvm/llvm-project · GitHub and related issues. I posted a fix recently at [clang-format] Limit how much work guessLanguage() can do by HighCommander4 · Pull Request #78925 · llvm/llvm-project · GitHub.
That appears to be the issue
This has been an issue for me too. I was able to reproduce it by opening cpp source files from a different project in VSCode while I was in one project. This caused clangd to start consuming all my systems memory as well.
Could it be that you also opened the simdjson file from another project folder?