interface IObject {
    foo()
}

struct Foo {}

fn (f Foo) foo() {
}

struct Array {
mut:
    array []IObject
}

fn (a Array) contains(x IObject) bool {
    for element in a.array {
        if element == x {
            return true
        }
    }
    return false
}

fn test_array_of_interfaces_equality() {
    foo := Foo{}
    mut ary := Array{}
    ary.array << foo
    ret := ary.contains(foo)
    println(ret)
    assert ret
}