public static ImmutableList<Accessors.BoundAccess> asBoundAccess(Iterable<?> iterable) {
    for (Object object : iterable) {
      checkArgument(object instanceof Accessors.BoundAccess);
    }
    return FluentIterable.from(iterable)
        .filter(Accessors.BoundAccess.class)
        .toList();
  }
Resolve accesors and types on {@link SimpleAccessExpression}, turning it into
{@link BoundAccessExpression}
generator-processor/src/org/immutables/generator/processor/TypeResolver.java