error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/rust-call.rs:10:7
   |
LL |     f(*slice);
   |       ^^^^^^ doesn't have a size known at compile-time
   |
   = help: within `([u8],)`, the trait `Sized` is not implemented for `[u8]`
   = note: required because it appears within the type `([u8],)`
   = note: argument required to be sized due to `extern "rust-call"` ABI

error: aborting due to 1 previous error

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