File: deriving-with-repr-packed-2.rs

package info (click to toggle)
rustc-web 1.70.0%2Bdfsg1-7~deb11u1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 1,517,036 kB
  • sloc: xml: 147,962; javascript: 10,210; sh: 8,590; python: 8,220; ansic: 5,901; cpp: 4,635; makefile: 4,006; asm: 2,856
file content (20 lines) | stat: -rw-r--r-- 687 bytes parent folder | download | duplicates (9)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
// 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
}