You've lost most of the semantics by the time you're at LLVM bitcode, since the high-level abstractions have been lowered into a basic for. Rust's type system

You've lost most of the semantics by the time you're at LLVM bitcode, since the high-level abstractions have been lowered into a basic for. Rust's type system provides memory and race safety, but those details are lost at a lower level. It's very hard to analyze data races at the assembly level!