The Rust formatting macros depend on string literals because the macro expansion necessarily happens at compile-time, which means that it's not possible to over

The Rust formatting macros depend on string literals because the macro expansion necessarily happens at compile-time, which means that it's not possible to override the actual format string at runtime, nor is recursive resolution possible. It's obviously still possible to implement the Display trait for a type in a way which makes it susceptible to code execution attacks, but that doesn't really have anything to do with string formatting.