Would you maybe if there's any source discussing how this is solved in different languages and performance consequences of it?
* In many languages, monomorphization is impractical. Eg, in C it requires macros or external code generators. Java and Go don't even have macros. So it's rarely done. Instead, stuff uses type erasure, dynamic dispatch, more heap allocations, and tables like the ones described in that dave.cheney.net link. Maybe some JITs or even some ahead-of-time compilers do monomorphization internally in some cases, but I'm speculating rather than speaking from knowledge.
* In C++ and Rust, monomorphization is easy. You don't have to do it, but it's easy, so many people do. The containers in the standard library are monomorphized. This code can perform very well in any particular case, but in aggregate it's large enough that I have doubts about whether it's always worth it for the whole program.
I suspect for this reason it'd be better in Rust to use a Go-like hash map implementation [1] that keeps all the key/value information (size, Hash and Eq implementations) in a vtable-like form rather than be monomorphized, except in really hot inner loops where the specialization is worth it. There was an interesting article and discussion on reddit relating to this [2] where someone made a toy type-erased map (though not as nice as Go's) to measure the difference in compilation times. Maybe some day I'll make a more production-ready attempt...
[1] https://dave.cheney.net/2018/05/29/how-the-go-runtime-implem...
[2] https://www.reddit.com/r/rust/comments/g1skz4/an_experiment_...