error[E0277]: the size for values of type `[u8]` cannot be known at compilation time --> $DIR/cannot-call-unsized-via-ptr.rs:5:24 | LL | let f: fn([u8]) = |_result| {}; | ^^^^^^^ 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 error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0277`.