Nim is built like this. The gc is opt-in by type and manual memory management is simple. All other types are stack allocated by default.

The new gc is pretty much compiler assisted scope managed smart pointers as well. Also when using the gc you can build your own types with custom create/free/copy/move operators to do what you want without worrying about a stop the world gc.

Using the arc gc pretty much compiles down to what you'd do manually. For cycles you can use the orc gc, again it's all opt in.

I find this a great balance of productivity and performance, where it's easy to have high control when you want it, and still get good performance when you're not bothered.