Suppose you want implement Display
and Debug
traits for your struct, but the output is the same. Instead of copy & paste the implementation, you can delegate the implementation by casting the Self
type to the trait type:
impl std::fmt::Debug for MyStruct { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "MyStruct"); } } impl std::fmt::Display for HRESULT { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { <Self as std::fmt::Debug>::fmt(self, f) // delegate } }
As a reminder, the Self
casting can be useful in other situations.
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