private String typeParamsString() {
    return TypeSimplifier.actualTypeParametersString(autoValueClass);
  }
Returns a set of all abstract methods in the given TypeElement or inherited from ancestors. If
any of the abstract methods has a return type or parameter type that is not currently defined
then this method will throw an exception that will cause us to defer processing of the current
class until a later annotation-processing round.
value/src/main/java/com/google/auto/value/processor/BuilderSpec.java