// revisions: old re #![cfg_attr(re, feature(re_rebalance_coherence))] #![feature(optin_builtin_traits)] auto trait MySafeTrait {} struct Foo; unsafe impl MySafeTrait for Foo {} //[old]~^ ERROR implementing the trait `MySafeTrait` is not unsafe //[re]~^^ ERROR E0199 unsafe auto trait MyUnsafeTrait {} impl MyUnsafeTrait for Foo {} //[old]~^ ERROR the trait `MyUnsafeTrait` requires an `unsafe impl` declaration //[re]~^^ ERROR E0200 fn main() {}