E4046

A public definition cannot depend on private entities.

Erroneous Example

priv trait I { m(Self) }
pub impl I for Int with m(self) {}

The above example tries to implement a private trait I for the type Int, but the implementation itself is public, which is not allowed. This gives the following error on line 2:

A public definition cannot depend on private trait

Suggestion

Adjust the visibility of the trait or the implementation to match:

trait I { m(Self) -> Unit }
pub impl I for Int with m(self) {}

... or:

priv trait I { m(Self) -> Unit }
impl I for Int with m(self) {}