Good...but why does the author think modern compilers / language servers DON'T do caching? Or in another way: why does the author think caching mechanism in modern compiler / language server is insufficient? I think the author is proposing a caching mechanism that has finer granularity and design the whole system around this idea from day one. But first, at least many components in LLVM have been doing caching for a long time (e.g. OrcJIT has a pretty decent caching layer and libTooling also supports incremental parsing with AST caches). Second, what is the memory overhead of this (fine grain caching) design when it's facing some larger input program in real world (e.g. OS kernel)? Does it scale well?

I know it's refurbished from an old post so I probably shouldn't be so harsh. But it will be better to compare some old ideas against state-of art works and found some insights rather than doing pure archaeology