I thought this level of entitlement was restricted to open source users, not devs. AFAIK Rust never promised anything re: the compile-time performance of its

I thought this level of entitlement was restricted to open source users, not devs. AFAIK Rust never promised anything re: the compile-time performance of its standard library, and I know of no 3rd party library that does. You link in a 3rd party library, then that's your code now for better or for worse.