error: `extern` fn uses type `[u32]`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:73:33
   |
LL | pub extern "C" fn slice_type(p: &[u32]) { }
   |                                 ^^^^^^ not FFI-safe
   |
   = help: consider using a raw pointer instead
   = note: slices have no C equivalent
note: the lint level is defined here
  --> $DIR/lint-ctypes-fn.rs:4:9
   |
LL | #![deny(improper_ctypes_definitions)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: `extern` fn uses type `str`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:76:31
   |
LL | pub extern "C" fn str_type(p: &str) { }
   |                               ^^^^ not FFI-safe
   |
   = help: consider using `*const u8` and a length instead
   = note: string slices have no C equivalent

error: `extern` fn uses type `Box<[u8]>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:83:34
   |
LL | pub extern "C" fn boxed_slice(p: Box<[u8]>) { }
   |                                  ^^^^^^^^^ not FFI-safe
   |
   = note: box cannot be represented as a single pointer

error: `extern` fn uses type `Box<str>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:86:35
   |
LL | pub extern "C" fn boxed_string(p: Box<str>) { }
   |                                   ^^^^^^^^ not FFI-safe
   |
   = note: box cannot be represented as a single pointer

error: `extern` fn uses type `Box<dyn Trait>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:89:34
   |
LL | pub extern "C" fn boxed_trait(p: Box<dyn Trait>) { }
   |                                  ^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: box cannot be represented as a single pointer

error: `extern` fn uses type `char`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:92:32
   |
LL | pub extern "C" fn char_type(p: char) { }
   |                                ^^^^ not FFI-safe
   |
   = help: consider using `u32` or `libc::wchar_t` instead
   = note: the `char` type has no C equivalent

error: `extern` fn uses type `i128`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:95:32
   |
LL | pub extern "C" fn i128_type(p: i128) { }
   |                                ^^^^ not FFI-safe
   |
   = note: 128-bit integers don't currently have a known stable ABI

error: `extern` fn uses type `u128`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:98:32
   |
LL | pub extern "C" fn u128_type(p: u128) { }
   |                                ^^^^ not FFI-safe
   |
   = note: 128-bit integers don't currently have a known stable ABI

error: `extern` fn uses type `(i32, i32)`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:101:33
   |
LL | pub extern "C" fn tuple_type(p: (i32, i32)) { }
   |                                 ^^^^^^^^^^ not FFI-safe
   |
   = help: consider using a struct instead
   = note: tuples have unspecified layout

error: `extern` fn uses type `(i32, i32)`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:104:34
   |
LL | pub extern "C" fn tuple_type2(p: I32Pair) { }
   |                                  ^^^^^^^ not FFI-safe
   |
   = help: consider using a struct instead
   = note: tuples have unspecified layout

error: `extern` fn uses type `ZeroSize`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:107:32
   |
LL | pub extern "C" fn zero_size(p: ZeroSize) { }
   |                                ^^^^^^^^ not FFI-safe
   |
   = help: consider adding a member to this struct
   = note: this struct has no fields
note: the type is defined here
  --> $DIR/lint-ctypes-fn.rs:28:1
   |
LL | pub struct ZeroSize;
   | ^^^^^^^^^^^^^^^^^^^

error: `extern` fn uses type `ZeroSizeWithPhantomData`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:110:40
   |
LL | pub extern "C" fn zero_size_phantom(p: ZeroSizeWithPhantomData) { }
   |                                        ^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: composed only of `PhantomData`
note: the type is defined here
  --> $DIR/lint-ctypes-fn.rs:63:1
   |
LL | pub struct ZeroSizeWithPhantomData(PhantomData<i32>);
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: `extern` fn uses type `PhantomData<bool>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:113:51
   |
LL | pub extern "C" fn zero_size_phantom_toplevel() -> PhantomData<bool> {
   |                                                   ^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: composed only of `PhantomData`

error: `extern` fn uses type `fn()`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:118:30
   |
LL | pub extern "C" fn fn_type(p: RustFn) { }
   |                              ^^^^^^ not FFI-safe
   |
   = help: consider using an `extern fn(...) -> ...` function pointer instead
   = note: this function pointer has Rust-specific calling convention

error: `extern` fn uses type `fn()`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:121:31
   |
LL | pub extern "C" fn fn_type2(p: fn()) { }
   |                               ^^^^ not FFI-safe
   |
   = help: consider using an `extern fn(...) -> ...` function pointer instead
   = note: this function pointer has Rust-specific calling convention

error: `extern` fn uses type `i128`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:126:39
   |
LL | pub extern "C" fn transparent_i128(p: TransparentI128) { }
   |                                       ^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: 128-bit integers don't currently have a known stable ABI

error: `extern` fn uses type `str`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:129:38
   |
LL | pub extern "C" fn transparent_str(p: TransparentStr) { }
   |                                      ^^^^^^^^^^^^^^ not FFI-safe
   |
   = help: consider using `*const u8` and a length instead
   = note: string slices have no C equivalent

error: `extern` fn uses type `PhantomData<bool>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:175:43
   |
LL | pub extern "C" fn unused_generic2<T>() -> PhantomData<bool> {
   |                                           ^^^^^^^^^^^^^^^^^ not FFI-safe
   |
   = note: composed only of `PhantomData`

error: `extern` fn uses type `Vec<T>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:188:39
   |
LL | pub extern "C" fn used_generic4<T>(x: Vec<T>) { }
   |                                       ^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
   = note: this struct has unspecified layout

error: `extern` fn uses type `Vec<T>`, which is not FFI-safe
  --> $DIR/lint-ctypes-fn.rs:191:41
   |
LL | pub extern "C" fn used_generic5<T>() -> Vec<T> {
   |                                         ^^^^^^ not FFI-safe
   |
   = help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
   = note: this struct has unspecified layout

error: aborting due to 20 previous errors