You're thinking about rust the wrong way. When you want to write in that exploratory way you should use a language that supports it, like Python, Javascript, or Lisp. These are all memory–safe languages that trade run–time speed for developer productivity. You can implement new features in them extremely quickly, and later if performance becomes an issue you can reimplement in Rust with the benefit of already knowing what you are writing.
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You're thinking about rust the wrong way. When you want to write in that exploratory way you should use a language that supports it, like Python, Javascript, or Lisp. These are all memory–safe languages that trade run–time speed for developer productivity. You can implement new features in them extremely quickly, and later if performance becomes an issue you can reimplement in Rust with the benefit of already knowing what you are writing.