error[E0277]: the size for values of type `(dyn std::fmt::Display + 'static)` cannot be known at compilation time --> $DIR/capture-unsized-by-move.rs:7:9 | LL | let k2 = move || { | -- this closure captures all values by move LL | k.to_string(); | ^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `(dyn std::fmt::Display + 'static)` = note: all values captured by value by a closure must have a statically known size error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.