Conditional compilation with Rust Analyzer in VSCode

I use a feature to control conditional compilation. Unfortunately, switching from one feature to another is inconvenient. I have a bunch of tasks in my tasks.json for checking, building, and running, each of which takes the feature. In addition, I use check-on-save, so I also have to change settings.json. I tried using VSCode environment settings, but I couldn't get that to work. Is there a simpler way to switch features?