Productivity, for me, does not mean "lines of code per day" or any similar measurement. (The fastest code is the code you don't have to write, and all that...)
Productivity is about refactoring. Getting the code "just right"; fixing bugs, adding necessary features, removing unnecessary ones. And Rust makes refactoring amazingly good. This is probably one of the most underrated features of the language.
In many cases, it is possible to completely rearchitect the underlying code while leaving the public API as-is, and without introducing new bugs. I've literally never had such a liberating experience with refactoring until Rust.
In other words, I have never been so productive in any other language. Dynamic languages like JavaScript and Python are the least productive by far. Code runs, tests pass, put it into production and... uncaught exception! Time to rollback and redo that whole dance AGAIN. With Rust, we take care of all of that crap while actually writing the code the first time. No more surprise 3am wake up calls. That is productivity.