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-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0204.md | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0204.md b/compiler/rustc_error_codes/src/error_codes/E0204.md new file mode 100644 index 000000000..96e44758b --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0204.md @@ -0,0 +1,28 @@ +The `Copy` trait was implemented on a type which contains a field that doesn't +implement the `Copy` trait. + +Erroneous code example: + +```compile_fail,E0204 +struct Foo { + foo: Vec<u32>, +} + +impl Copy for Foo { } // error! +``` + +The `Copy` trait is implemented by default only on primitive types. If your +type only contains primitive types, you'll be able to implement `Copy` on it. +Otherwise, it won't be possible. + +Here's another example that will fail: + +```compile_fail,E0204 +#[derive(Copy)] // error! +struct Foo<'a> { + ty: &'a mut bool, +} +``` + +This fails because `&mut T` is not `Copy`, even when `T` is `Copy` (this +differs from the behavior for `&T`, which is always `Copy`). |