new TypeToken<SingleGenericExtendsBase<String>>() {};
    assertTrue(subtype.isSubtypeOf(supertype));
    ParameterizedType actualSubtype =
        (ParameterizedType) supertype.getSubtype(subtype.getRawType()).getType();
    assertEquals(SingleGenericExtendsBase.class, actualSubtype.getRawType());
    assertTrue(TypeToken.of(actualSubtype).isSubtypeOf(supertype));
  }

        new TypeToken<SingleGenericExtendsBase<String>>() {};
    assertTrue(subtype.isSubtypeOf(supertype));
    ParameterizedType actualSubtype =
        (ParameterizedType) supertype.getSubtype(subtype.getRawType()).getType();
    assertEquals(SingleGenericExtendsBase.class, actualSubtype.getRawType());
    assertTrue(TypeToken.of(actualSubtype).isSubtypeOf(supertype));
  }

    Type paramType = getOnlyParameterType();
    TestSubtype spec = method.getAnnotation(TestSubtype.class);
    assertWithMessage("%s is subtype of %s", paramType, returnType)
        .that(TypeToken.of(paramType).isSubtypeOf(returnType))
        .isTrue();
    assertWithMessage("%s is supertype of %s", returnType, paramType)
        .that(TypeToken.of(returnType).isSupertypeOf(paramType))
        .isTrue();
    if (!spec.suppressGetSubtype()) {

          // may generate something like <capture#1-of ? extends Foo&SubFoo>.
          // Checking subtype between declared and actual type bounds
          // adds recursive isSubtypeOf() call and feels complicated.
          // There is no contract one way or another as long as isSubtypeOf() works as expected.
          combined.addAll(asList(typeParam.getBounds()));
          if (combined.size() > 1) { // Object is implicit and only useful if it's the only bound.

          // may generate something like <capture#1-of ? extends Foo&SubFoo>.
          // Checking subtype between declared and actual type bounds
          // adds recursive isSubtypeOf() call and feels complicated.
          // There is no contract one way or another as long as isSubtypeOf() works as expected.
          combined.addAll(asList(typeParam.getBounds()));
          if (combined.size() > 1) { // Object is implicit and only useful if it's the only bound.