E0184 - Error codes index
Description: Book listing all Rust error codes

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# Error code E0184

The `Copy` trait was implemented on a type with a `Drop` implementation.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    #[derive(Copy)]
    struct Foo; // error!

    impl Drop for Foo {
        fn drop(&mut self) {
        }
    }
    }

Explicitly implementing both `Drop` and `Copy` trait on a type is currently disallowed. This feature can make some sense in theory, but the current implementation is incorrect and can lead to memory unsafety (see issue #20126), so it has been disabled for now.