pub trait TypeFinder {
// Required method
fn find_types(&self, types: &mut HashSet<TypeRef>);
// Provided method
fn all_types(&self) -> HashSet<TypeRef> { ... }
}
pub trait TypeFinder {
// Required method
fn find_types(&self, types: &mut HashSet<TypeRef>);
// Provided method
fn all_types(&self) -> HashSet<TypeRef> { ... }
}