So I have no idea about rust, but in c++ a big feature of templated code is that you can make type appropriate specializations, is that not possible in Rust or did its standard library maintainers just sleep on the job?
But it would also be uncommon in C++ to specialize to pass by value. Generic code normally just passes T by reference, ex. max, push_back. Since this is transparent to the caller in C++ though, you don't have to write the &s.
Last I checked (a month or two ago), the specialization feature warning even included a bit about how it can crash the compiler (the crashes were the reason I gave up on specialization two years ago)
Edit: Turns out theres been some progress since I used it last! Feature `min_specialization` seems to not be a non-crashing subset of specialization [1]