error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/issue-30355.rs:5:8
   |
LL |     &X(*Y)
   |        ^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `[u8]`
   = note: all function arguments must have a statically known size
   = help: unsized fn params are gated as an unstable feature

error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/issue-30355.rs:5:6
   |
LL |     &X(*Y)
   |      ^ doesn't have a size known at compile-time
   |
   = help: within `X`, the trait `Sized` is not implemented for `[u8]`
note: required because it appears within the type `X`
  --> $DIR/issue-30355.rs:1:12
   |
LL | pub struct X([u8]);
   |            ^
   = note: the return type of a function must have a statically known size

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.