rust-lang/rust — pull request #18629 by stepancheg (2014-11-04 21:34:56+00:00)
Title: Clarify Error description and detail should be single line

When description and detail are known to be single line, they can
be used like this, and programmer can be sure that message is
formatted nicely.

```
println!("could not download file: {}, trying again in 5s", e.description());
```