| Feature attributes are only allowed on the nightly release channel. Stable or | |
| beta compilers will not comply. | |
| Erroneous code example: | |
| ```ignore (depends on release channel) | |
| #![feature(lang_items)] // error: `#![feature]` may not be used on the | |
| // stable release channel | |
| ``` | |
| If you need the feature, make sure to use a nightly release of the compiler | |
| (but be warned that the feature may be removed or altered in the future). |