pub static ORDER_DEPENDENT_TRAIT_OBJECTS: &Lint
Expand description
The order_dependent_trait_objects
lint detects a trait coherency
violation that would allow creating two trait impls for the same
dynamic trait object involving marker traits.
§Example
ⓘ
pub trait Trait {}
impl Trait for dyn Send + Sync { }
impl Trait for dyn Sync + Send { }
{{produces}}
§Explanation
A previous bug caused the compiler to interpret traits with different
orders (such as Send + Sync
and Sync + Send
) as distinct types
when they were intended to be treated the same. This allowed code to
define separate trait implementations when there should be a coherence
error. This is a future-incompatible lint to transition this to a
hard error in the future. See issue #56484 for more details.