Androidstudio 运行 mod.rs文件一直报这个错误

[winnxiegang]

C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\private\ser.rs:294:9
|
294 | try!(state.serialize_field(self.tag, self.variant_name));
| -------------------------------------------------------- in this macro invocation
|
= note: this error originates in the macro try (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0425]: cannot find function, tuple struct or tuple variant Some in this scope
--> C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\private\ser.rs:319:56
|
319 | let mut map = try!(self.delegate.serialize_map(Some(2)));
| ^^^^ not found in this scope
|
help: consider importing one of these items
|
1 + use __private::de::Content::Some;
|
1 + use __private::ser::Content::Some;
|

error[E0531]: cannot find tuple struct or tuple variant Ok in this scope
--> C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\lib.rs:280:13
|
280 | Ok(val) => val,
| ^^ not found in this scope
|
::: C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\private\ser.rs:319:23
|
319 | let mut map = try!(self.delegate.serialize_map(Some(2)));
| ------------------------------------------ in this macro invocation
|
= note: this error originates in the macro try (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0531]: cannot find tuple struct or tuple variant Err in this scope
--> C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\lib.rs:281:13
|
281 | Err(err) => return Err(err),
| ^^^ not found in this scope
|
::: C:\Users\hp.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\serde-1.0.152\src\private\ser.rs:319:23
|
319 | let mut map = try!(self.delegate.serialize_map(Some(2)));
| -------