| #### Note: this error code is no longer emitted by the compiler. | |
| A `#[coverage(off|on)]` attribute was found in a position where it is not | |
| allowed. | |
| Coverage attributes can be applied to: | |
| - Function and method declarations that have a body, including trait methods | |
| that have a default implementation. | |
| - Closure expressions, in situations where attributes can be applied to | |
| expressions. | |
| - `impl` blocks (inherent or trait), and modules. | |
| Example of erroneous code: | |
| ```ignore (no longer emitted) | |
| unsafe extern "C" { | |
| #[coverage(off)] | |
| fn foreign_fn(); | |
| } | |
| ``` | |
| When using the `-C instrument-coverage` flag, coverage attributes act as a | |
| hint to the compiler that it should instrument or not instrument the | |
| corresponding function or enclosed functions. The precise effect of applying | |
| a coverage attribute is not guaranteed and may change in future compiler | |
| versions. |