src/test/ui/transmute/transmute-imut-to-mut.rs

   1 // Tests that transmuting from &T to &mut T is Undefined Behavior.
   2
   3 use std::mem::transmute;
   4
   5 fn main() {
   6     let _a: &mut u8 = unsafe { transmute(&1u8) };
   7     //~^ ERROR transmuting &T to &mut T is undefined behavior, even if the reference is unused, consider instead using an UnsafeCell
   8 }