Why isn't the Copy trait implemented for String?

[Cr0a3]

Why isn't the Copy trait implemented for the type String?

I tried this code:

#[derive(Copy, Clone)]
enum MyEnum {
  abc(String),
}

But i got following error:

error[E0204]: the trait `Copy` cannot be implemented for this type
 --> src\test.rs:1:17
  |
1 | #[derive(Clone, Copy)]
  |                 ^^^^
...
w |     Abc(String),
  |           ------ this field does not implement `Copy`
  |
  = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)

[workingjubilee]

@Toni-Graphics Hello, is your question answered by consulting the String docs or Copy docs?

[workingjubilee]

Hm. It seems it takes quite a while for the String docs to even imply that the value might be heap-allocated and thus not possible to trivially Copy... "btw this allocates" should probably be one of the first things on it (not in detail, that's covered in Representation).

[JaniM]

@rustbot claim
First rustc contribution, so not sure of the protocol here.
I'll add a disclaimer to the documentation.