error[E0277]: the size for values of type `[{integer}]` cannot be known at compilation time --> $DIR/issue-17651.rs:5:18 | LL | (|| Box::new(*(&[0][..])))(); | -------- ^^^^^^^^^^^ doesn't have a size known at compile-time | | | required by a bound introduced by this call | = help: the trait `Sized` is not implemented for `[{integer}]` note: required by a bound in `Box::::new` --> $SRC_DIR/alloc/src/boxed.rs:LL:COL help: references are always `Sized`, even if they point to unsized data; consider not dereferencing the expression | LL - (|| Box::new(*(&[0][..])))(); LL + (|| Box::new((&[0][..])))(); | error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0277`.