Tracking ownership doesn't make the Rust compiler slow. Compiling Rust is already faster in general than compiling C++ (where the lack of a module system and code explosion from templates is absolutely killer), with the caveat that the Rust compiler hasn't yet implemented incremental recompilation and so subsequent compilations can be slower than subsequent compilations in C++ if your C++ build system is reusing artifacts intelligently. Incremental compilation in Rust is slated for after the middle-end overhaul which is currently ongoing.

Hmm ok, this has probably increased a lot since I last dabbled with Rust. This was about a year ago, and the speed reminded me of a C++ static analyzer, which kinda made sense to me :)

Even in C++ land there are massive differences in compiler speed Clang on Linux/OSX is easily 10x faster than the Visual Studio compiler without advanced tweaks (however, for some reason, clang on Windows is also very slow).

Yes, when I talk about C++ compiler speed I generally mean Clang, since it's a widely-available high-quality implementation with compiler speed as an explicit priority. In the context of Rust it's doubly relevant since they both use LLVM. Compiler speed wasn't an explicit priority for the Rust developers in the run-up to 1.0, but these days it's essentially top priority (hence the aforementioned middle end overhaul, though it has more benefits than just incremental recompilation), and the speed of the compiler has already more than doubled since 1.0.