// issue: rust-lang/rust#80125 //@ check-pass type ExternCallback = extern "C" fn(*const u8, u32, str); //~^ WARN `extern` fn uses type `str`, which is not FFI-safe pub struct Struct(ExternCallback); #[no_mangle] pub extern "C" fn register_something(bind: ExternCallback) -> Struct { //~^ WARN `extern` fn uses type `str`, which is not FFI-safe //~^^ WARN `extern` fn uses type `Struct`, which is not FFI-safe Struct(bind) } fn main() {}