1error[E0038]: the trait `StreamingIterator` cannot be made into an object 2 --> $DIR/trait-objects.rs:10:21 3 | 4LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize { 5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `StreamingIterator` cannot be made into an object 6 | 7note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> 8 --> $DIR/trait-objects.rs:4:10 9 | 10LL | trait StreamingIterator { 11 | ----------------- this trait cannot be made into an object... 12LL | type Item<'a> where Self: 'a; 13 | ^^^^ ...because it contains the generic associated type `Item` 14 = help: consider moving `Item` to another trait 15 16error: aborting due to previous error 17 18For more information about this error, try `rustc --explain E0038`. 19