code: private static ImmutableList<Rule> initRules(
        AbstractCompiler compiler, ImmutableList<ConformanceConfig> configs) {
      ImmutableList.Builder<Rule> builder = ImmutableList.builder();
      List<Requirement> requirements = mergeRequirements(compiler, configs);
      for (Requirement requirement : requirements) {
        Rule rule = initRule(compiler, requirement);
        if (rule != null) {
          builder.add(rule);
        }
      }
      return builder.build();
    }
docs: Build the data structures need by this pass from the provided
  configurations.