rust/tests/ui/derives/deriving-with-repr-packed-2.rs
2023-01-31 20:28:11 +01:00

21 lines
687 B
Rust

// Check that deriving certain builtin traits on certain packed structs cause
// errors. To avoid potentially misaligned references, field copies must be
// used, which involves adding `T: Copy` bounds.
#[derive(Copy, Clone, Default, PartialEq, Eq)]
#[repr(packed)]
pub struct Foo<T>(T, T, T);
struct NonCopy;
fn main() {
// This one is fine because `u32` impls `Copy`.
let x: Foo<u32> = Foo(1, 2, 3);
_ = x.clone();
// This one is an error because `NonCopy` doesn't impl `Copy`.
let x: Foo<NonCopy> = Foo(NonCopy, NonCopy, NonCopy);
_ = x.clone();
//~^ ERROR the method `clone` exists for struct `Foo<NonCopy>`, but its trait bounds were not satisfied
}