error: `extern` block uses type `U`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:60:13
   |
LL |    fn uf(x: U);
   |             ^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint
note: the type is defined here
  --> $DIR/lint-ctypes-enum.rs:9:1
   |
LL | enum U {
   | ^^^^^^
note: the lint level is defined here
  --> $DIR/lint-ctypes-enum.rs:3:9
   |
LL | #![deny(improper_ctypes)]
   |         ^^^^^^^^^^^^^^^

error: `extern` block uses type `B`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:61:13
   |
LL |    fn bf(x: B);
   |             ^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint
note: the type is defined here
  --> $DIR/lint-ctypes-enum.rs:12:1
   |
LL | enum B {
   | ^^^^^^

error: `extern` block uses type `T`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:62:13
   |
LL |    fn tf(x: T);
   |             ^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint
note: the type is defined here
  --> $DIR/lint-ctypes-enum.rs:16:1
   |
LL | enum T {
   | ^^^^^^

error: `extern` block uses type `u128`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:74:23
   |
LL |    fn nonzero_u128(x: Option<num::NonZeroU128>);
   |                       ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: 128-bit integers don't currently have a known stable ABI

error: `extern` block uses type `i128`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:81:23
   |
LL |    fn nonzero_i128(x: Option<num::NonZeroI128>);
   |                       ^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: 128-bit integers don't currently have a known stable ABI

error: `extern` block uses type `Option<TransparentUnion<NonZeroU8>>`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:86:28
   |
LL |    fn transparent_union(x: Option<TransparentUnion<num::NonZeroU8>>);
   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint

error: `extern` block uses type `Option<Rust<NonZeroU8>>`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:88:20
   |
LL |    fn repr_rust(x: Option<Rust<num::NonZeroU8>>);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint

error: `extern` block uses type `Result<(), NonZeroI32>`, which is not FFI-safe
  --> $DIR/lint-ctypes-enum.rs:89:20
   |
LL |    fn no_result(x: Result<(), num::NonZeroI32>);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]`, `#[repr(transparent)]`, or integer `#[repr(...)]` attribute to this enum
   = note: enum has no representation hint

error: aborting due to 8 previous errors