error[E0308]: mismatched types
  --> $DIR/issue-71676-2.rs:41:22
   |
LL |     let _: *mut u8 = &a;
   |            -------   ^^ types differ in mutability
   |            |
   |            expected due to this
   |
   = note: expected raw pointer `*mut u8`
                found reference `&Emm`
help: consider dereferencing
   |
LL |     let _: *mut u8 = &mut ***a;
   |                       ^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.