使用通用生命周期时，借用的价值寿命不够长？

Question

使用通用生命周期\xe3\x80\x82时借用的值没有足够长的寿命

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fn get<'a, T>(&self, key: &[u8]) -> Result<Option<T>>\nwhere\n    T: Deserialize<'a>,\n{\n    match self.db.get(key)? {\n        Some(dbv) => {\n            let v = serde_json::from_slice(&*dbv)?;\n            Ok(Some(v))\n        }\n        None => Ok(None),\n    }\n}\n

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函数 db.get 声明：

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pub fn get(&self, key: &[u8]) -> Result<Option<DBVector>, String>\n

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函数 serde_json::from_slice 声明：

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pub fn from_slice<'a, T>(v: &'a [u8]) -> Result<T>\nwhere\n    T: de::Deserialize<'a>\n

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错误消息：

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error[E0597]: `dbv` does not live long enough\n   --> libs/block-db/src/index.rs:106:50\n    |\n100 |     fn get<'a, T>(&self, key: &[u8]) -> Result<Option<T>>\n    |            -- lifetime `'a` defined here\n...\n106 |                 let v = serde_json::from_slice(&*dbv)?;\n    |                         -------------------------^^^-\n    |                         |                        |\n    |                         |                        borrowed value does not live long enough\n    |                         argument requires that `dbv` is borrowed for `'a`\n...\n109 |             None => Ok(None),\n    |                - `dbv` dropped here while still borrowed\n\nerror: aborting due to previous erro\n

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Answer 1

fn get<T>(&self, key: &[u8]) -> Result<Option<T>>
where
    T: DeserializeOwned,
{
    match self.db.get(key)? {
        Some(ref dbv) => {
            let v = serde_json::from_slice(dbv)?;
            Ok(Some(v))
        }
        None => Ok(None),
    }
}