This just seems to illustrate the complexity of compiler authorship. I am very sure c compilers are wble to address this issue any better in the general case.
Keep in mind Rust is using the same backend as one of the main C compilers, LLVM. So if it is handling it any better that means the Clang developers handle it before it even reaches the shared LLVM backend. Well, or there is something about the way Clang structures the code that catches a pattern in the backend the Rust developers do not know about.