warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/specialization-trait-item-not-implemented.rs:3:12
   |
LL | #![feature(specialization)]
   |            ^^^^^^^^^^^^^^
   |
   = note: `#[warn(incomplete_features)]` on by default
   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
   = help: consider using `min_specialization` instead, which is more stable and complete

error[E0046]: not all trait items implemented, missing: `foo_two`
  --> $DIR/specialization-trait-item-not-implemented.rs:18:1
   |
LL |     fn foo_two(&self) -> &'static str;
   |     ---------------------------------- `foo_two` from trait
...
LL | impl Foo for MyStruct {}
   | ^^^^^^^^^^^^^^^^^^^^^ missing `foo_two` in implementation

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0046`.