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Specialization should allow for delegation to default trait method implementation #68309
Description
Given the following trait:
trait Trait {
fn test(&self) { println!("default implementation"); }
}To provide a default specialization on Trait::test, test must be redefined;
impl<T> Trait for T {
default fn test(&self) { println!("default implementation"); }
}However this violates the DRY principle. The solution here would be to provide a way to delegate the implementation of test to the already existing default implementation found in the trait definition.
Proposed syntax to allow for this delegation:
impl<T> Trait for T {
default fn test(&self);
}Reacted by Ellen Emilia Anna Zscheile and Jeriel Baptista Verissimo
Activity
jazzfool commentedon Jan 17, 2020
cc @Centril
Centril commentedon Jan 17, 2020
I believe this is intentional fallout from #64564 (cc @jonas-schievink).
Having some sort of forwarding syntax to recover DRY seems reasonable and
default fn test(&self);isn't a bad one.jonas-schievink commentedon Jan 17, 2020
Yup, sounds reasonable to me. I noticed the amount of repetition when working on that PR too:
Centril commentedon Jan 17, 2020
Syntactic support for
default fn test(&self);in animplshould already be there after #67131. To support it semantically we would need changes in lowering and beyond.