Error code E0600
An unary operator was used on a type which doesn't implement it.
Erroneous code example:
#![allow(unused)] fn main() { enum Question { Yes, No, } !Question::Yes; // error: cannot apply unary operator `!` to type `Question` }
In this case, Question
would need to implement the std::ops::Not
trait in
order to be able to use !
on it. Let's implement it:
#![allow(unused)] fn main() { use std::ops::Not; enum Question { Yes, No, } // We implement the `Not` trait on the enum. impl Not for Question { type Output = bool; fn not(self) -> bool { match self { Question::Yes => false, // If the `Answer` is `Yes`, then it // returns false. Question::No => true, // And here we do the opposite. } } } assert_eq!(!Question::Yes, false); assert_eq!(!Question::No, true); }