How to fix String field does not implement `Copy`? [duplicate]

Question

I am building a simple command-line todo app in Rust. If I don't implement the copy trait I get this error: "move occurs because 'todo' has type 'todo::Todo', which does not implement the 'Copy' trait". When I try to implement the Copy trait for my Todo struct, I receive the following error: "field text: String does not implement the Copy trait". How do I fix this error? My code is below:

pub type todo_type = Vec<Todo>;

#[derive(Copy)]
pub struct Todo {
    id: usize,
    text: String,
    completed: bool,
}

impl Todo {
    pub fn new(text: String, id: usize) -> Todo {
        Todo {
            text,
            id,
            completed: false,
        }
    }
}

pub struct Todos {
    todos: todo_type,
}

impl Todos {
    pub fn new(todos: todo_type) -> Todos {
        Todos { todos }
    }

    pub fn get_all_todos(self) -> todo_type {
        self.todos
    }

    pub fn get_single_todo(self, todo_index: usize) -> Todo {
        unimplemented!()
    }

    pub fn add_todo(self, text: String) -> Todo {
        let id: usize = 1;

        if self.todos.len() == 0 {
            let id = 1;
        } else {
            let last_todo = match self.todos.len() {
                0 => None,
                n => Some(&self.todos[n - 1]),
            };
            let id = last_todo.unwrap().id;
        }

        let todo = Todo::new(text, id);
        self.todos.push(todo);

        todo
    }

    pub fn remove_todo(self, todo_index: usize) -> bool {
        self.todos.remove(todo_index);

        true
    }
}

Answer 1

Here you need the Clone trait instead of Copy trait. The Copy trait indicates that the variable can be copied bit-for-bit exactly as is, and that the variables of such type do not underly to move semantics.

Some limitations apply to implementations of Copy trait. It is so, that structs can implement the Copy trait only if none of their components implements the Drop trait. Since String implements the Drop trait, your struct can not implement the Copy.

If you are looking to be making copies of your struct, then you need Clone trait.