fnis_copy<T: Copy>() {}fntypes_impl_copy_trait() { is_copy::<bool>(); is_copy::<char>();// all iXX and uXX, usize/isize, fXX implement Copy trait is_copy::<i8>(); is_copy::(); is_copy::(); is_copy::<usize>();// function (actually a pointer) ...
types_impl_copy_trait里的类型都是实现了Copy trait的。 fn is_copy<T: Copy>() {} fn types_impl_copy_trait() { is_copy::<bool>(); is_copy::<char>(); // all iXX and uXX, usize/isize, fXX implement Copy trait is_copy::<i8>(); is_copy::(); is_copy::(); is_copy::<...
Clone Trait:尽管 Clone trait 通常包含一个方法,即 clone 方法,但它在某种意义上也可以看作是一个 marker trait,因为 Clone 通常与 Copy 一起使用来指示一个类型可以通过 .clone() 方法进行显式的复制。 Default Trait:Default trait 同样包含一个方法来创建类型的默认值,但仍可认为是一个语义特指的 marker t...
types_impl_copy_trait里的类型都是实现了Copy trait的。 代码语言:javascript 复制 fn is_copy<T:Copy>(){}fntypes_impl_copy_trait(){is_copy::<bool>();is_copy::<char>();// all iXX and uXX, usize/isize, fXX implement Copy traitis_copy::<i8>();is_copy::();is_copy::();is_cop...
但是要使 #[derive(Copy, Clone)] 起作用,struct 或 enum 的所有成员必须可以 Copy。例如,下面代码就不起作用: // error:the trait `Copy` may not be implemented for this type// because its nums field does not implement `Copy`#[derive(Copy,Clone)]struct Numbers{nums:Vec<i32>} ...
| -- move occurs because `s1` has type `String`, which does not implement the `Copy` trait 4 | let s2 = s1; | -- value moved here 5 | 6 | println!("{}, world!", s1); | ^^ value borrowed here after move | = note: this error originates in the macro `$crate::format_...
/// | -- move occurs because `s1` has type `String`, which does not implement the `Copy` trait /// 3 | let s2 = s1; /// | -- value moved here /// 4 | /// 5 | println!("{}, world!", s1); /// | ^^ value borrowed here after move ...
-- move occurs because `s1` hastype`String`, which does not implement the `Copy` trait 3 | let s2 = s1; -- value moved here 4 | 5 | println!("{}, world!", s1); ^^ value borrowed here after move For more information about thiserror, try `rustc --explain E0382`. ...
| -- move occurs because `s1` hastype`String`,whichdoes not implement the `Copy` trait 4 |lets2 = s1; | -- value moved here 5 | 6 | println!("{}, world!", s1); | ^^ value borrowed here after move | = note: this error originatesinthe macro `$crate::format_args_nl` (in...
结构可以是Copy,而i32是Copy,因此Point有资格成为Copy。相比之下,考虑 structPointList{points: Vec<Point>, } 结构PointList无法实现Copy,因为Vec<T>不是Copy。如果我们尝试派生Copy实现,我们会得到一个错误: the trait `Copy` maynotbe implementedforthistype; field `points` doesnotimplement `Copy` ...