Serde: cannot find derive macro `Serialize` in this scope (depend on importing format)

[dmitryvakulenko]

I don't know why but if I import Serialize like this use serde::ser::Serialize; I get error

error: cannot find derive macro `Serialize` in this scope
  --> src/requester/mod.rs:14:10
   |
14 | #[derive(Serialize)]
   |        

But if I import like use serde::Serialize; everything Ok.

[songroom2016]

i have same question also."cannot find derive macro Serialize in this scope"
my code:

#![feature(proc_macro_hygiene,decl_macro)]
#[macro_use] extern crate rocket;
use serde::{Serialize, Deserialize};
 #[derive(Serialize, Deserialize, Debug)]
 struct Point{
        x: Vec<f64>,
        y: Vec<i32>,
        z:Vec<String>,
 }
#[get("/<code>/<startdate>/<enddate>")]
fn get_price(code: String, startdate: String,enddate:String) -> String {
        let point = Point { x: vec![1.0f64,2.0,3.0], y: vec![2_i32,3,4,5],z:vec!["a".into(),"b".into(),"c".into(),"d".into()] };
        let json_string = serde_json::to_string(&point).unwrap();
        json_string
}
fn main() {
    rocket::ignite().mount("/get_price", routes![get_price]).launch();
}

error:

error: cannot find derive macro `Serialize` in this scope
 --> src\main.rs:5:11
  |
5 |  #[derive(Serialize, Deserialize, Debug)]
  |           ^^^^^^^^^

error: cannot find derive macro `Deserialize` in this scope
 --> src\main.rs:5:22
  |
5 |  #[derive(Serialize, Deserialize, Debug)]
  |                      ^^^^^^^^^^^

warning: unused imports: `Deserialize`, `Serialize`
 --> src\main.rs:4:13
  |
4 | use serde::{Serialize, Deserialize};
  |             ^^^^^^^^^  ^^^^^^^^^^^
  |= note: `#[warn(unused_imports)]` on by default

error[E0277]: the trait bound `Point: serde::ser::Serialize` is not satisfied
  --> src\main.rs:14:27
   |
14 |         let json_string = serde_json::to_string(&point).unwrap();
   |                           ^^^^^^^^^^^^^^^^^^^^^ the trait `serde::ser::Serialize` is not implemented for `Point`
   |
   = note: required by `serde_json::ser::to_string`

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0277`.
error: Could not compile `rust_plot`.

Caused by:
  process didn't exit successfully: `rustc --edition=2018 --crate-name rust_plot src\main.rs --color never --crate-type bin --emit=dep-info,link -C opt-
level=3 -C metadata=2fc579e68a7bb85b -C extra-filename=-2fc579e68a7bb85b --out-dir D:\rust_plot\target\release\deps -L dependency=D:\rust_plot\target\re
lease\deps --extern rocket=D:\rust_plot\target\release\deps\librocket-4ca9dd94486d7b84.rlib --extern rocket_contrib=D:\rust_plot\target\release\deps\lib
rocket_contrib-90137ffd80943fbe.rlib --extern serde=D:\rust_plot\target\release\deps\libserde-b09781ea79315232.rlib --extern serde_derive=D:\rust_plot\t
arget\release\deps\serde_derive-419b0f41938cb2c4.dll --extern serde_json=D:\rust_plot\target\release\deps\libserde_json-6da4c838b62aa43c.rlib -L native=
D:\rust_plot\target\release\build\ring-a35e82e2d3ca382a\out` (exit code: 1)

---

toml:

[dependencies]
rocket = { path = "D:/Rocket-master/Rocket-master/core/lib" }#"0.4.1"
serde = "1.0"
serde_json = "1.0"
serde_derive = "1.0"
#hdf5 = "0.5"
rocket_contrib = { path = "D:/Rocket-master/Rocket-master/contrib/lib"}

D:\rust_plot>cargo tree
rust_plot v0.1.0 (D:\rust_plot)
├── serde v1.0.92
├── serde_derive v1.0.100
│ ├── proc-macro2 v1.0.3
│ │ └── unicode-xid v0.2.0
│ ├── quote v1.0.2
│ │ └── proc-macro2 v1.0.3 ()
│ └── syn v1.0.5
│ ├── proc-macro2 v1.0.3 ()
│ ├── quote v1.0.2 ()
│ └── unicode-xid v0.2.0 ()
└── serde_json v1.0.39
├── itoa v0.4.4
├── ryu v0.2.8
└── serde v1.0.92 (*)

other:

1.39 nightly +win10

thanks

[ghost]

@dmitryvakulenko

The serde::ser::Serialize is a trait, so you cannot use it in attributes as in #[derive(...)].

The serde::Serialize is _also_ a trait, but re-exported from the serde::ser path.

https://github.com/serde-rs/serde/blob/d1ade378270ecf85dfab0df6fce816cab7971c14/serde/src/lib.rs#L244

The serde::Serialize is _also_ a macro, but re-exported from the serde_derive crate. You _must_ enable the derive feature for the serde dependency in your manifest file for this to work.

https://github.com/serde-rs/serde/blob/d1ade378270ecf85dfab0df6fce816cab7971c14/serde/src/lib.rs#L257-L268

---

@songroom2016

I think you should either use serde_derive when importing Serialize and Deserialize macros or enable the derive feature in your manifest file.

---

@dmitryvakulenko @songroom2016

For further clarification: https://serde.rs/derive.html.

[songroom2016]

it works.
use serde::{Serialize, Deserialize};
=>
use serde_derive::{Serialize, Deserialize};
thanks

[dmitryvakulenko]

@rustka, thank you for explanation!

[ralpha]

This worked for me:

[dependencies]
serde = { version = "1.0", features = ["derive"] }

Found here: https://stackoverflow.com/questions/49113368/how-do-i-fix-cannot-find-derive-macro-in-this-scope