const Derp = opaque {};
const Wat = opaque {};

extern fn bar(d: *Derp) void;
fn foo(w: *Wat) callconv(.c) void {
    bar(w);
}

test "call foo" {
    foo(undefined);
}

// test_error=expected type '*test_opaque.Derp', found '*test_opaque.Wat'
