* [Concatenating strings with `format!`](idioms/concat-format.md)
* private field to indicate extensibility
* trait to separate visibility of methods from visibility of data (https://github.com/sfackler/rust-postgres/blob/master/src/lib.rs#L1400)
* Deref on Vec/String to treat like a smart pointer/borrowed view of such data
* leak amplification ("Vec::drain sets the Vec's len to 0 prematurely so that mem::forgetting Drain "only" mem::forgets more stuff. instead of exposing uninitialized memory or having to update the len on every iteration")
* newtype (can be used to restrict functionality, make by-move rather than by-copy, abstraction, e.g., https://github.com/rust-lang/rust/blob/master/src/libcore/str/mod.rs#L366-L372)