static ImmutableSet<Parameter> forParameterList(
      List<? extends VariableElement> variables, Types types, InjectApi injectApi) {
    List<TypeMirror> variableTypes = Lists.newArrayListWithExpectedSize(variables.size());
    for (VariableElement var : variables) {
      variableTypes.add(var.asType());
    }
    return forParameterList(variables, variableTypes, types, injectApi);
  }
Annotations on the parameter (not its type).
factory/src/main/java/com/google/auto/factory/processor/Parameter.java