Rust has another advantage in the language itself- generic code can be type-checked and (partially) optimized before being instantiated. When you export a gene

Rust has another advantage in the language itself- generic code can be type-checked and (partially) optimized before being instantiated. When you export a generic function in C++, every file that pulls it in has to re-parse it, and every instantiation has to re-type-check it. C++20 modules should help with the first part, but they can't help with the second (and neither can concepts). Further, separate translation units can wind up duplicating the same instantiations, which the linker has to deduplicate. When you export a generic function in Rust, by the time it gets pulled in somewhere else, it takes the form of pre-parsed, pre-type-checked MIR. It can also be pre-optimized, so type-independent optimization work is shared between instantiations. The compiler can also tell, before instantiation, which type parameters a function does not actually depend on, and essentially erase them ("polymorphization"). Further, Rust's compilation model reduces the redundant duplicate instantiations C++ does, both by using larger translation units and by automatically sharing any instantiations in dependencies with their dependents (though you can do this by hand in C++). (Incidentally, these differences also apply to inline functions- in C++ you wind up putting their definitions in headers and recompiling them from scratch over and over; in Rust they are shared MIR form.)