error[E0495]: cannot infer an appropriate lifetime for autoref due to conflicting requirements
  --> $DIR/dyn-trait-underscore.rs:8:20
   |
LL |     Box::new(items.iter())
   |                    ^^^^
   |
note: first, the lifetime cannot outlive the anonymous lifetime #1 defined on the function body at 6:1...
  --> $DIR/dyn-trait-underscore.rs:6:1
   |
LL | / fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
LL | |     //                      ^^^^^^^^^^^^^^^^^^^^^ bound *here* defaults to `'static`
LL | |     Box::new(items.iter())
LL | | }
   | |_^
note: ...so that reference does not outlive borrowed content
  --> $DIR/dyn-trait-underscore.rs:8:14
   |
LL |     Box::new(items.iter())
   |              ^^^^^
   = note: but, the lifetime must be valid for the static lifetime...
note: ...so that the expression is assignable
  --> $DIR/dyn-trait-underscore.rs:8:5
   |
LL |     Box::new(items.iter())
   |     ^^^^^^^^^^^^^^^^^^^^^^
   = note: expected  `std::boxed::Box<(dyn std::iter::Iterator<Item = &T> + 'static)>`
              found  `std::boxed::Box<dyn std::iter::Iterator<Item = &T>>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0495`.