Various FFI run-pass tests probably should be using `repr(C)` as lint is instructing.

[pnkfelix]

The following run-pass tests cause the improper_ctypes lint to fire. It would probably be fine (and trivial) to add #[repr(C)] to them.

rust/src/test/run-pass/extern-pass-TwoU16s.rs

Line 17 in c2afca3

pub struct TwoU16s {

rust/src/test/run-pass/extern-pass-TwoU32s.rs

Line 17 in c2afca3

pub struct TwoU32s {

rust/src/test/run-pass/extern-pass-TwoU64s.rs

Line 17 in c2afca3

pub struct TwoU64s {

rust/src/test/run-pass/extern-pass-TwoU8s.rs

Line 17 in c2afca3

pub struct TwoU8s {

rust/src/test/run-pass/extern-return-TwoU16s.rs

Line 13 in c2afca3

pub struct TwoU16s {

rust/src/test/run-pass/extern-return-TwoU32s.rs

Line 13 in c2afca3

pub struct TwoU32s {

rust/src/test/run-pass/extern-return-TwoU64s.rs

Line 13 in c2afca3

pub struct TwoU64s {

rust/src/test/run-pass/extern-return-TwoU8s.rs

Line 13 in c2afca3

pub struct TwoU8s {

rust/src/test/run-pass/foreign-fn-with-byval.rs

Line 14 in c2afca3

pub struct S {

rust/src/test/run-pass/issue-3656.rs

Line 23 in c2afca3

pub struct KEYGEN {

rust/src/test/run-pass/issue-5754.rs

Line 13 in c2afca3

struct TwoDoubles {

rust/src/test/run-pass/issue-6470.rs

Line 14 in c2afca3

pub struct Foo {

(I'm just filing this ticket so I have something to point at from a PR for #53764.)

[asquared31415]

@rustbot claim

[asquared31415]

@rustbot release-assignment