| A trait method was declared const. | |
| Erroneous code example: | |
| ```compile_fail,E0379 | |
| trait Foo { | |
| const fn bar() -> u32; // error! | |
| } | |
| ``` | |
| Trait methods cannot be declared `const` by design. For more information, see | |
| [RFC 911]. | |
| [RFC 911]: https://github.com/rust-lang/rfcs/pull/911 |