the trait `Copy` may not be implemented for this type when implement in rust

When I added copy in the rust struct like this:

fn main() {

}

#[derive(Debug, Default, Copy)]
pub struct BillRecord {
    pub id: Option<i64>,
    pub remark: Option<String>
}

shows error info when compile:

➜  rust-learn git:(group-by) ✗ cargo build
   Compiling rust-learn v0.1.0 (/Users/xiaoqiangjiang/source/reddwarf/backend/rust-learn)
error[E0204]: the trait `Copy` may not be implemented for this type
  --> src/main.rs:7:26
   |
7  | #[derive(Debug, Default, Copy)]
   |                          ^^^^
...
10 |     pub remark: Option<String>
   |     -------------------------- this field does not implement `Copy`
   |
note: the `Copy` impl for `std::option::Option<std::string::String>` requires that `std::string::String: Copy`
  --> src/main.rs:10:5
   |
10 |     pub remark: Option<String>
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0204`.
error: could not compile `rust-learn` due to previous error

what should I do to implement the Copy? I just want to implement the Copy trait, did not want to implement the Clone trait. this code block need to implement the Copy trait:

fn main() {
    let source = &BillRecord{ id: None, remark: None };
    let a = BillRecordResponse{ id: source.id, remark: source.remark };
}

#[derive(Debug, Serialize, Default, Clone)]
pub struct BillRecord {
    pub id: Option<i64>,
    pub remark: Option<String>
}

use serde::Serialize;

#[derive(Debug, Serialize, Default)]
pub struct BillRecordResponse {
    pub id: Option<i64>,
    pub remark: Option<String>
}

when I compile this code block, shows error:

error[E0507]: cannot move out of `source.remark` which is behind a shared reference
 --> src/main.rs:5:56
  |
5 |     let a = BillRecordResponse{ id: source.id, remark: source.remark };
  |                                                        ^^^^^^^^^^^^^ move occurs because `source.remark` has type `std::option::Option<std::string::String>`, which does not implement the `Copy` trait
  |
help: consider borrowing the `Option`'s content
  |
5 |     let a = BillRecordResponse{ id: source.id, remark: source.remark.as_ref() };
  |                                                                     +++++++++

For more information about this error, try `rustc --explain E0507`.
warning: `rust-learn` (bin "rust-learn") generated 1 warning
error: could not compile `rust-learn` due to previous error; 1 warning emitted

>Solution :

The error message is saying that String does not implement Copy (so Option<String> does not either), so therefore Copy cannot be derived for your struct (which contains an Option<String>).

As Copy signifies cheap copyability, and a String may contain a lot of characters (making it not cheaply copyable), String should not implement Copy. Therefore you should not try to implement Copy, but instead implement Clone and use clone() where necessary:

fn main() {
    let source = &BillRecord{ id: None, remark: None };
    let a = BillRecordResponse{ id: source.id, remark: source.remark.clone() };
}

#[derive(Debug, Serialize, Default, Clone)]
pub struct BillRecord {
    pub id: Option<i64>,
    pub remark: Option<String>
}

use serde::Serialize;

#[derive(Debug, Serialize, Default, Clone)]
pub struct BillRecordResponse {
    pub id: Option<i64>,
    pub remark: Option<String>
}