how to convert from AccountInfo to UncheckedAccount?

Question

use anchor_lang::prelude::*;
use anchor_spl::token::TokenAccount;

#[derive(Accounts, Clone)]
pub struct InstructionTest<'info> {
    pub account: Account<'info, TokenAccount>,
}

pub fn test(ctx: Context<InstructionTest>) {
    let account_info = ctx.accounts.account.to_account_info();
    let unchecked_account = UncheckedAccount::try_from(&account_info); // report error
}

account_info does not live long enough

Answer 1

Let me see if I can explain it correctly. According to anchor_lang doc, below is definition of UncheckedAccount

#[derive(Debug, Clone)]
pub struct UncheckedAccount<'info>(&'info AccountInfo<'info>);

So according to this, the lifetime of param passed (AccountInfo) should match the lifetime of object UncheckedAccount.

Lets see the below code

pub fn test(ctx: Context<InstructionTest>) {
  let account_info = ctx.accounts.account.to_account_info();
  let unchecked_account = UncheckedAccount::try_from(&account_info);//report error
}

The lifetime of account_info is the lifetime of function which calls test function. So we can assume lifetime of ctx is longer than the test function at the minimum. The variable unchecked_account will die at the end of the function test, so unchecked_account and account_info lifetimes do not match

But according to the definition of UncheckedAccount the lifetime of inner param should match the lifetime of UncheckedAccount, so this gives an error