[kokada]

Author here.

I think you misundertood how this feature works.

If you have a `go.mod` that sets a `go` directive with a version bigger than the version your Go toolchain is currently running, it will download the binary automatically and pass the commands to the new binary. However this doesn't replace your `go` binary in say, PATH, the new toolchain will be downloaded at `GOPATH`, the same as it does with your modules. This is why there is nothing to backup here, nothing is deleted.

Also, keep in mind that if Go is downloading a new toolchain, it means your project will not work with the current toolchain: because if you set `go 1.23` in your `go.mod`, and your current `go` is version 1.22, it would fail regardless until you either fix your `go.mod` or upgrade your `go` toolchain. What Go is doing here is the later, automatically for you.