rust/tests/compile-fail/function_calls/exported_symbol_abi_mismatch.rs

// revisions: no_cache cache fn_ptr

#[no_mangle]
fn foo() {}

fn main() {
    #[cfg(any(cache, fn_ptr))]
    extern "Rust" {
        fn foo();
    }

    #[cfg(fn_ptr)]
    unsafe { std::mem::transmute::<unsafe fn(), unsafe extern "C" fn()>(foo)() }
    //[fn_ptr]~^ ERROR calling a function with calling convention Rust using calling convention C

    // `Instance` caching should not suppress ABI check.
    #[cfg(cache)]
    unsafe { foo() }

    {
        #[cfg_attr(any(cache, fn_ptr), allow(clashing_extern_declarations))]
        extern "C" {
            fn foo();
        }
        unsafe { foo() }
        //[no_cache]~^ ERROR calling a function with calling convention Rust using calling convention C
        //[cache]~^^ ERROR calling a function with calling convention Rust using calling convention C
    }
}