Rollup merge of #62514 - stephaneyfx:box-ffi, r=nikomatsakis

[rust.git] / src / librustc_error_codes / error_codes / E0648.md

`export_name` attributes may not contain null characters (`\0`).

```compile_fail,E0648
#[export_name="\0foo"] // error: `export_name` may not contain null characters
pub fn bar() {}
```