Missing lifetime error?

[kornel]

You're running into the dangerous mix of unsafe pointers and automatic destruction:

CString/.as_ptr() is incredibly unsafe

I knew that CString::new().as_ptr() is dangerous, so I consciously avoided that convenient construct, and still, I got a use-after-free. I needed a nullable string for a C function, so I wrote: let option = Some("foo"); // Explicitly bind CString to a variable to keep it alive let c_option = option.and_then(|s| CString::new(s).ok()); // And it's not alive! This causes use-after-free, and Rust is doesn't say a word about it let p = c_option.map(|c| c.as_ptr()).unwrap_or(ptr::null()); // And…