如何取消引用切片引用

问：

我需要取消引用切片，然后使用变量 a。

    let mut a: [i8; 10] = [42; 10];
    a[5] = 0;
    let mut s = &mut a[2..4];
    s[0] = 100;
    let mut aa = &mut *s;
    aa[1] = 23;
    let release = *aa;
    println!(" s:{:#?}   a:{:#?}",  s, a);

我收到有关未知大小的编译时错误

error[E0277]: the size for values of type `[i8]` cannot be known at compilation time
 let release = *aa;
   ^^^^^^^ doesn't have a size known at compile-time

取消引用切片引用