#![feature(negative_impls)] #![feature(specialization)] //~ WARN the feature `specialization` is incomplete trait MyTrait {} struct TestType(::std::marker::PhantomData); unsafe impl Send for TestType {} impl !Send for TestType {} //~^ ERROR found both positive and negative implementation of trait `Send` for type `TestType<_>` //~| ERROR `!Send` impl requires `T: MyTrait` but the struct it is implemented for does not fn main() {}