Trait Ref 

pub trait Ref:
    Eq
    + Hash
    + Debug
    + Default
    + Display
    + Clone { }

The Ref trait represents the type of references that can be used in the conditions. It must implement Eq, Hash, Debug, Default, Display, and Clone.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors