//@ compile-flags:-Ztranslate-lang=en_US #![feature(negative_impls)] #![feature(marker_trait_attr)] #[marker] trait MyTrait {} struct TestType(::std::marker::PhantomData); unsafe impl Send for TestType {} impl !Send for TestType {} //~ ERROR found both positive and negative implementation unsafe impl Send for TestType {} //~ ERROR conflicting implementations impl !Send for TestType {} fn main() {}