!7

sclass BetterThreadLocal<A> {
  Map<Thread, A> map = newWeakHashMap();
  
  A get() {
    ret map.get(currentThread());
  }
  
  void set(A a) {
    mapPutOrRemove(map, currentThread(), a);
  }
}

static new BetterThreadLocal<S> tl;

p {
  assertNull(tl!);
  tl.set("hello");
  assertEq("hello", tl!);
  thread {
    assertNull(tl!);
  }
  sleepSeconds(1);
  tl.set(null);
  assertNull(tl!);
}