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# Error code E0740

A `union` was declared with fields with destructors.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    union Test {
        a: A, // error!
    }

    #[derive(Debug)]
    struct A(i32);

    impl Drop for A {
        fn drop(&mut self) { println!("A"); }
    }
    }

A `union` cannot have fields with destructors.