遇到一些问题

[beckbikang]

error[E0658]: use of unstable library feature 'inner_deref': newly added
--> /Users/macy/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/lettre-0.9.3/src/smtp/commands.rs:248:61
|
248 | Some(mechanism.response(&credentials, challenge.as_deref())?)
| ^^^^^^^^
|
= note: for more information, see rust-lang/rust#50264

error: aborting due to previous error

For more information about this error, try rustc --explain E0658.

[danloh]

what's your rustc version? it is OK here on 1.46