Trait syllogism::IsNot

pub trait IsNot<T> { }

A trait to inform the compiler that two data types are distinct.

This allows you to use specialization up to some extend. See the crate level documentation for more info.

A data type should never implement IsNot<Self>.

Implementing IsNot correctly for each pair of data types at hand can be error prone. E.g. if there are three data types at play, T1, T2, T3. If you want to allow specialization for any of these data types, giving the other two the “default” treatment, then you need six implementations of the IsNot trait:

use syllogism::IsNot;

impl IsNot<T2> for T1 {}
impl IsNot<T3> for T1 {}
impl IsNot<T1> for T2 {}
impl IsNot<T3> for T2 {}
impl IsNot<T1> for T3 {}
impl IsNot<T2> for T3 {}

The syllogism-macro crate provides procedural macros to generate these impls for you, and also offers some techniques that allow extending the set of data types across crate boundaries. We refer to the documentation of the syllogism-macro crate for more information.

Implementors