error[E0308]: mismatched types
  --> $DIR/unsize_tuple.rs:8:28
   |
LL | fn hello() -> ([impl Sized; 2],) {
   |                 ---------- the found opaque type
...
LL |         let _: &([i32],) = &x;
   |                ---------   ^^ expected `&([i32],)`, found `&([impl Sized; 2],)`
   |                |
   |                expected due to this
   |
   = note: expected reference `&([i32],)`
              found reference `&([impl Sized; 2],)`

error: aborting due to 1 previous error

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