@marchelzo pointed out on IRC that this doesn't have docs, so, let's
change that.
/// If parsing succeeds, return the value inside `Ok`, otherwise
/// when the string is ill-formatted return an error specific to the
/// inside `Err`. The error type is specific to implementation of the trait.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage with [`i32`][ithirtytwo], a type that implements `FromStr`:
+ ///
+ /// [ithirtytwo]: ../primitive.i32.html
+ ///
+ /// ```
+ /// use std::str::FromStr;
+ ///
+ /// let s = "5";
+ /// let x = i32::from_str(s).unwrap();
+ ///
+ /// assert_eq!(5, x);
+ /// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn from_str(s: &str) -> Result<Self, Self::Err>;
}