IllegalArgumentException.class, () -> map.getInstance(this.<Number>anyIterableType()));
  }

  public void testPut_containsTypeVariable() {
    ImmutableTypeToInstanceMap.Builder<Iterable<Integer>> builder =
        ImmutableTypeToInstanceMap.builder();
    assertThrows(
        IllegalArgumentException.class,
        () -> builder.put(this.<Integer>anyIterableType(), ImmutableList.of(1)));
  }

        IllegalArgumentException.class, () -> map.getInstance(this.<Number>anyIterableType()));
  }

  public void testPutInstance_withTypeVariable() {
    assertThrows(
        IllegalArgumentException.class,
        () -> map.putInstance(this.<Integer>anyIterableType(), ImmutableList.of(1)));
  }

  private <T> TypeToken<Iterable<T>> anyIterableType() {
    return new TypeToken<Iterable<T>>() {};
  }