error[E0046]: not all trait items implemented, missing: `foo` --> $DIR/trivial_impl2.rs:10:1 | LL | / fn foo() LL | | where LL | | Self: Foo<()>; | |______________________- `foo` from trait ... LL | impl Foo for () {} | ^^^^^^^^^^^^^^^^^^^^ missing `foo` in implementation error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0046`.