无法将类型隐式转换为ActionResult <t>

Question

我在Mvc Core 2中有一些基本代码试图利用T和ActionResult<T>之间的隐式转换。

    public ActionResult<IEnumerable<FrequentlyAskedQuestion>> Test()
    {
        IEnumerable<FrequentlyAskedQuestion> x = new FrequentlyAskedQuestion[0];
        return x;
    }

我收到此错误

2>Controllers\FaqsController.cs(57,20,57,21): error CS0029: Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<Models.FrequentlyAskedQuestion>' to 'Microsoft.AspNetCore.Mvc.ActionResult<System.Collections.Generic.IEnumerable<Models.FrequentlyAskedQuestion>>'

如果我允许它保留为数组，那就可以了。

    public ActionResult<IEnumerable<FrequentlyAskedQuestion>> Test()
    {
        var x = new FrequentlyAskedQuestion[0];
        return x;
    }

我可以看到AspNetCore的代码有这个静态隐式运算符，这对于它来说很好用

    public static implicit operator ActionResult<TValue>(TValue value)
    {
        return new ActionResult<TValue>(value);
    }