I doubt that would help, since generic code is implicitly inline.
Heck with explicit template instantiation the generic code may not even be in the same translation unit as the calling code. At that point it'd require link time optimization to inline it.
Maybe I’m misunderstanding you.
> This is true in monomorphized languages like Rust
It's not necessarily true for monomorphized code. Inlining is enabled by monomorphization, but is not required.
You can see it with templates in C++: function template instantiations aren't always inlined. They are instantiated in every TU separately, if they are defined in headers, but then they may be called in this TU just like any other function without inlining. This requires the linker to deduplicate the instantiations later. In another scenario you may declare a function template in a header without the implementation, putting the implementation in a CPP file along with explicit instantiation. In that case the compiler is not able to inline this function in another TU (without LTO).
As for Rust, Rust is not universally monomorphized. The user of generic code in Rust gets to decide whether they want to use monomorphization or vtables, regardless of the ideas of the author of said generic code.
this thread is about function call inlining.