}


  public void testWeak_afterGC() throws InterruptedException {
    MyInt canonical = new MyInt(5);
    MyInt not = new MyInt(5);

    Interner<MyInt> pool = Interners.newWeakInterner();
    assertThat(pool.intern(canonical)).isSameInstanceAs(canonical);

    WeakReference<MyInt> signal = new WeakReference<>(canonical);
    canonical = null; // Hint to the JIT that canonical is unreachable

  }


  public void testWeak_afterGC() throws InterruptedException {
    MyInt canonical = new MyInt(5);
    MyInt not = new MyInt(5);

    Interner<MyInt> pool = Interners.newWeakInterner();
    assertThat(pool.intern(canonical)).isSameInstanceAs(canonical);

    WeakReference<MyInt> signal = new WeakReference<>(canonical);
    canonical = null; // Hint to the JIT that canonical is unreachable

must be itself, and <code>T</code> cannot be an interface.
</p>

<pre>
type MyInt int

interface {
	~[]byte  // the underlying type of []byte is itself
	~MyInt   // illegal: the underlying type of MyInt is not MyInt
	~error   // illegal: error is an interface
}
</pre>

<p>
Union elements denote unions of type sets:
</p>

<pre>