//@ check-pass
//@ run-rustfix

extern "C" {
    fn test();
}

fn a() {}

extern "C" fn c() {}

extern "C" fn args(_a: i32) -> i32 { 0 }

#[derive(PartialEq, Eq)]
struct A {
    f: fn(),
}

fn main() {
    let f: fn() = a;
    let g: fn() = f;

    let a1 = A { f };
    let a2 = A { f };

    let _ = std::ptr::fn_addr_eq(f, a as fn());
    //~^ WARN function pointer comparisons
    let _ = !std::ptr::fn_addr_eq(f, a as fn());
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(f, g);
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(f, f);
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(g, g);
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(g, g);
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(g, g);
    //~^ WARN function pointer comparisons
    let _ = std::ptr::fn_addr_eq(a as fn(), g);
    //~^ WARN function pointer comparisons

    let cfn: extern "C" fn() = c;
    let _ = std::ptr::fn_addr_eq(cfn, c as extern "C" fn());
    //~^ WARN function pointer comparisons

    let argsfn: extern "C" fn(i32) -> i32 = args;
    let _ = std::ptr::fn_addr_eq(argsfn, args as extern "C" fn(i32) -> i32);
    //~^ WARN function pointer comparisons

    let t: unsafe extern "C" fn() = test;
    let _ = std::ptr::fn_addr_eq(t, test as unsafe extern "C" fn());
    //~^ WARN function pointer comparisons

    let _ = a1 == a2; // should not warn
    let _ = std::ptr::fn_addr_eq(a1.f, a2.f);
    //~^ WARN function pointer comparisons
}