Add mention to RFC 940 in the Rust Reference.
It also keeps mentions to RFCs consistent with the format "RFC XXX"
@@ -853,6 +853,20 @@ extern crate std; // equivalent to: extern crate std as std;
extern crate std as ruststd; // linking to 'std' under another name
```
+When naming Rust crates, hyphens are disallowed. However, Cargo packages may
+make use of them. In such case, when `cargo.toml` doesn't specify a crate name,
+Cargo will transparently replace `-` with `_` (Refer to [RFC 940] for more
+details).
+
+Here is an example:
+
+```{.ignore}
+// Importing the Cargo package hello-world/
+extern crate hello_world; // The crate name replaced the hyphen
+```
+
+[RFC 940]: https://github.com/rust-lang/rfcs/blob/master/text/0940-hyphens-considered-harmful.md
+
#### Use declarations
A _use declaration_ creates one or more local name bindings synonymous with
