Address

import nxt.nullable_traits : hasNullValue, isNullable;
import nxt.open_hashmap : OpenHashMap;

static assert(hasNullValue!Address);
static assert(isNullable!Address);

OpenHashMap!(Address, Address) m;

static assert(m.sizeof == 3*size_t.sizeof); // assure that hole bitmap is not used

foreach (const address; 1 .. 0x1000)
{
    const key = address;
    const value = 2*address;

    assert(Address(key) !in m);

    m[Address(key)] = Address(value);

    assert(m[Address(key)] == Address(value));
    assert(Address(key) in m);
}