Attribute Macro explainable 

#[explainable]

Annotate an operation trait to generate the full explaining scaffolding for every method in that trait.

Receiver-type handling

• self (consuming) — uses std::mem::replace to move the value out safely.
• &self / &mut self returning Self or Result<Self, E> — calls directly.
• &mut self returning () or Result<(), E> — calls for side-effect only.

Associated-type propagation

Method parameters that reference Self::X (associated types from a supertrait) are handled by declaring type X; in the generated FooExt trait and setting type X = T::X; in the blanket impl. No substitution of method signatures is needed.

#[cfg(…)] propagation

#[cfg(…)] attributes on individual trait methods are forwarded to all generated items.