You made a bad argument, hide your ego in your pocket and admit it instead of writing such a nonsense. Both clang and Rust compiler are based on LLVM and they both can target only those platforms that LLVM target. If you can't use clang today then you can't use Rust also. We are not talking about "hypothetical" situations or alternative worlds because in those situations i can say whatever I want about clang also...
You didn't even reply to what I wrote? We are talking about Rust and Clang compilers and platforms they target and this was the context. It started when you tried to belittle Clang because it shows warnings and then you tried to make argument about hypothetical Rust compiler that can target OS that Clang can't, again trying to show Rust > C++. Even if you can't show superiority of Rust over C++ you are inventing hypothetical compilers that you think will work as your argument. If anyone will read your comments then he can see you are obviously biased and your ego just magnifies that effect. Think about it, objectively, get some air, there is world besides HN also.
Just because the only existing Rust compiler uses LLVM, it doesn't mean another implementations will not surface.
So hypothetical the OS not targeted by clang, can still have a Rust compiler on the OS SDK, offering all safety guarantees from Rust.
For example, there are OSes and hardware architectures not supported by clang that have Ada and even Java AOT compilers.