error[E0277]: the size for values of type `dyn std::iter::Iterator<Item = &'a mut u8>` cannot be known at compilation time
  --> $DIR/issue-20605.rs:2:17
   |
LL |     for item in *things { *item = 0 }
   |                 ^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `dyn std::iter::Iterator<Item = &'a mut u8>`
   = note: required by `std::iter::IntoIterator::into_iter`

error: aborting due to previous error

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