Most of the time, I let my IDE check the code with rls, rust-analyzer or cargo check which invokes the rust-compiler without doing the costly code generation part with LLVM, so it is usually fast enough checking huge projects while writing or at least when saving.

cargo doesn't do a terribly good job of caching dependencies.

Might be better than whatever C++ does though.

Currently C++ is still a better experience, because using binary dependencies is quite common, so you don't compile the whole world, rather just your own application.

Then most organizations have staging areas where you can share binaries across the company.

And the two package managers that have been growing community support, conan and vcpkg, support caching and distribution of binary dependencies.

No doubt cargo will eventually get something similar, it just isn't there today.

You can do this with a build script.

So goodbye declarative builds.

I thought I cared about declarativeness, turns out I don't.

Experience has taught me to always care about it, except when working on throw away hobby projects with teams of one, turns out not using it doesn't scale across organisations and makes for very unhappy DevOps teams.