interface Y {}

  static class A implements X, Y {}

  static class B implements X, Y {}

  /**
   * This test passes if the {@code concat(…).filter(…).filter(…)} statement at the end compiles.
   * That statement compiles only if {@link FluentIterable#concat concat(aIterable, bIterable)}
   * returns a {@link FluentIterable} of elements of an anonymous type whose supertypes are the <a

                .collect(Collectors.toList());
    }

    private Map<String, Lifecycle> lookupLifecycles() {
        // TODO: Remove the following code when maven-compat is gone
        // This code is here to ensure maven-compat's EmptyLifecycleExecutor keeps on working.
        if (lookup == null) {
            return customLifecycles != null ? customLifecycles : new HashMap<>();
        }

        ImmutableList.copyOf(
            Iterables.concat(
                Iterables.transform(POSITIVE_INTEGER_CANDIDATES, NEGATE_INT),
                ImmutableList.of(Integer.MIN_VALUE)));
    NONZERO_INTEGER_CANDIDATES =
        ImmutableList.copyOf(
            Iterables.concat(POSITIVE_INTEGER_CANDIDATES, NEGATIVE_INTEGER_CANDIDATES));
    ALL_INTEGER_CANDIDATES = Iterables.concat(NONZERO_INTEGER_CANDIDATES, ImmutableList.of(0));
  }

        ImmutableList.copyOf(
            Iterables.concat(
                Iterables.transform(POSITIVE_INTEGER_CANDIDATES, NEGATE_INT),
                ImmutableList.of(Integer.MIN_VALUE)));
    NONZERO_INTEGER_CANDIDATES =
        ImmutableList.copyOf(
            Iterables.concat(POSITIVE_INTEGER_CANDIDATES, NEGATIVE_INTEGER_CANDIDATES));
    ALL_INTEGER_CANDIDATES = Iterables.concat(NONZERO_INTEGER_CANDIDATES, ImmutableList.of(0));
  }

      Short[] prefix = {Short.MIN_VALUE, Short.MAX_VALUE};
      Short[] suffix = {(short) 86, (short) 99};
      Short[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Short[] concat(Short[] left, Short[] right) {
    Short[] result = new Short[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

      Character[] prefix = {Character.MIN_VALUE, Character.MAX_VALUE};
      Character[] suffix = {(char) 86, (char) 99};
      Character[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Character[] concat(Character[] left, Character[] right) {
    Character[] result = new Character[left.length + right.length];

      Short[] prefix = {Short.MIN_VALUE, Short.MAX_VALUE};
      Short[] suffix = {(short) 86, (short) 99};
      Short[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Short[] concat(Short[] left, Short[] right) {
    Short[] result = new Short[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

      Long[] prefix = {Long.MIN_VALUE, Long.MAX_VALUE};
      Long[] suffix = {(long) 86, (long) 99};
      Long[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Long[] concat(Long[] left, Long[] right) {
    Long[] result = new Long[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

    assertThat(Bytes.concat()).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Bytes.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1, ARRAY1, ARRAY1))

              public void close() throws IOException {
                super.close();
                counter[0]--;
              }
            };
          }
        };
    Reader joinedReader = CharSource.concat(reader, reader, reader).openStream();
    String result = CharStreams.toString(joinedReader);
    assertEquals(testString.length() * 3, result.length());
  }

  public void testReady() throws Exception {