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 1 previous error

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