error[E0308]: mismatched types
  --> $DIR/issue-32122-1.rs:16:24
   |
LL |     let _: *const u8 = &a;
   |            ---------   ^^
   |            |           |
   |            |           expected `u8`, found struct `Foo`
   |            |           help: consider dereferencing: `&*a`
   |            expected due to this
   |
   = note: expected raw pointer `*const u8`
                found reference `&Foo`

error: aborting due to previous error

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