error[E0308]: mismatched types
  --> $DIR/issue-71676-2.rs:42:22
   |
LL |     let _: *mut u8 = &a;
   |            -------   ^^
   |            |         |
   |            |         types differ in mutability
   |            |         help: consider dereferencing: `&mut ***a`
   |            expected due to this
   |
   = note: expected raw pointer `*mut u8`
                found reference `&Emm`

error: aborting due to previous error

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