我正在try 编写一个通用代码，将一个json文件读入一个对象.但似乎我在这里遗漏了一些东西.

use serde::Deserialize;
use std::{error::Error, fs::File, io::Read};

pub fn from_file<'a, T>(filename: String) -> Result<T, Box<dyn Error>>
where
    T: Deserialize<'a>,
{
    let mut file = File::open(filename)?;
    let mut content: String = String::new();
    file.read_to_string(&mut content)?;
    Ok(serde_json::from_str::<T>(&content)?)
}

我收到以下错误

error[E0597]: `content` does not live long enough
  --> src\util\file.rs:11:34
   |
4  | pub fn from_file<'a, T>(filename: String) -> Result<T, Box<dyn Error>>
   |                  -- lifetime `'a` defined here
...
11 |     Ok(serde_json::from_str::<T>(&content)?)
   |        --------------------------^^^^^^^^-
   |        |                         |
   |        |                         borrowed value does not live long enough
   |        argument requires that `content` is borrowed for `'a`
12 | }
   | - `content` dropped here while still borrowed

For more information about this error, try `rustc --explain E0597`.
error: could not compile `flavour` due to previous error

我所理解的是，我必须绑定T，谢谢这SO question.但我不确定要增加哪些界限.

以及如何推断这类问题所需的界限.我试着读了from_str页，发现只需要T: de::Deserialize<'a>页.