| A negative impl was added on a trait implementation. | |
| Erroneous code example: | |
| ```compile_fail,E0192 | |
| trait Trait { | |
| type Bar; | |
| } | |
| struct Foo; | |
| impl !Trait for Foo { } //~ ERROR E0192 | |
| fn main() {} | |
| ``` | |
| Negative impls are only allowed for auto traits. For more | |
| information see the [opt-in builtin traits RFC][RFC 19]. | |
| [RFC 19]: https://github.com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md |