gfx

I was actually thinking about this precise issue this morning (due to this GitHub issue[1]). I think a valuable middleground would be to include this kind of check even without the ?Leave stuff. In essence, the compiler could just give an error if it would have needed to issue a Drop call anywhere for the type. This ability is pretty useful when dealing with destructors that need context that you don't want to always wrap with the given type (sometimes for performance reasons). [1]: https://github.com/gfx-rs/gfx/issues/1216

In accordance with federal law (http://n-gate.com/), I'm obligated to point out this Rust library, which does exactly this! https://github.com/gfx-rs/gfx. I worked on the second version of the API in 2014 and it's only gotten better since. The major thing this particular abstraction still doesn't solve is shaders: you need to write a shader per backend you support. Shader portability is a bit of a sticky problem.