我不明白这个警告：不应为方法或函数提供显式类型参数

Question

我有这个代码：

type BSCReply =
    {
        status:  int
        message: string
        result:  string
    }

let private decodeResult<'a> (result: IRestResponse) =
    let deserialize content =
        try
            Ok (JsonConvert.DeserializeObject<'b> content)
        with ex ->
            Error (HttpStatusCode.InternalServerError, ex.Humanize())

    match result.IsSuccessful with
    | true  ->  match deserialize<BSCReply> result.Content with
                | Ok r    -> deserialize<'a> r.result
                | Error e -> Error e
    | false ->  Error(result.StatusCode, result.ErrorMessage)

但是在编译时，我得到这个错误：

[FS0686] The method or function 'deserialize' should not be given explicit type argument(s) because it does not declare its type parameters explicitly

警告出现两次，每次使用 'deserialize'

我不明白这个错误，谁能解释一下？

Answer 1

我认为这里的问题是 deserialize 指的是您未在任何地方定义的类型 'b。要解决此问题，您应该将 deserialize 移到顶层并明确声明 'b。像这样：

let private deserialize<'b> content =
    try
        Ok (JsonConvert.DeserializeObject<'b> content)
    with ex ->
        Error (HttpStatusCode.InternalServerError, ex.Humanize())

let private decodeResult<'a> (result: IRestResponse) =
    match result.IsSuccessful with
    | true  ->  match deserialize<BSCReply> result.Content with
                | Ok r    -> deserialize<'a> r.result
                | Error e -> Error e
    | false ->  Error(result.StatusCode, result.ErrorMessage)

我不明白这个警告：不应为方法或函数提供显式类型参数

I do not understand this warning: The method or function should not be given explicit type argument(s)

f#