error[E0046]: not all trait items implemented, missing: `foo` --> $DIR/trivial_impl4.rs:18:1 | LL | / fn foo() LL | | where LL | | Self: trivial4::Trait; | |______________________________- `foo` from trait ... LL | impl Foo for u8 {} | ^^^^^^^^^^^^^^^ missing `foo` in implementation error: aborting due to previous error For more information about this error, try `rustc --explain E0046`.