ices/93622.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#93622

#![feature(unsized_fn_params)]

pub enum Tree {
    Node(Box<Tree>, Box<Tree>),
    Leaf,
}

pub type Cont<'a> = dyn Fn(u64) -> u64 + 'a;

pub fn height_cps<'a>(x : &'a Tree, k : Cont<'a>) -> u64 {
    match x {
        Tree::Leaf => k(0),
        Tree::Node(l, r) => {
            //                                          v-- causes crash
            height_cps(l, {let k : Box<Cont> = Box::new(move |lh| {
                height_cps(r, {let k : Box<Cont> = Box::new(|lr| { k(1 + lh.max(lr)) }); *k})
            }); *k})
        }
    }
}

fn main () {
    height_cps(&Tree::Leaf, *(Box::new(|i| {i}) as Box<Cont>));
}

=== stdout ===
=== stderr ===
error[E0277]: the size for values of type `(dyn Fn(u64) -> u64 + 'a)` cannot be known at compilation time
  --> /home/runner/work/glacier/glacier/ices/93622.rs:16:68
   |
15 |             height_cps(l, {let k : Box<Cont> = Box::new(move |lh| {
   |                                                              ---- this closure captures all values by move
16 |                 height_cps(r, {let k : Box<Cont> = Box::new(|lr| { k(1 + lh.max(lr)) }); *k})
   |                                                                    ^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `(dyn Fn(u64) -> u64 + 'a)`
   = 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`.
==============