Project with serde cannot compile

Question

When I try to run the example from the serde repository:

#![feature(proc_macro)]

#[macro_use]
extern crate serde_derive;

extern crate serde_json;

#[derive(Serialize, Deserialize, Debug)]
struct Point {
    x: i32,
    y: i32,
}

fn main() {
    let point = Point { x: 1, y: 2 };

    // Convert the Point to a JSON string.
    let serialized = serde_json::to_string(&point).unwrap();

    // Prints serialized = {"x":1,"y":2}
    println!("serialized = {}", serialized);

    // Convert the JSON string back to a Point.
    let deserialized: Point = serde_json::from_str(&serialized).unwrap();

    // Prints deserialized = Point { x: 1, y: 2 }
    println!("deserialized = {:?}", deserialized);
}

I get an error:

error: failed to run rustc to learn about target-specific information

Caused by: process didn't exit successfully: rustc - --crate-name _ --print=file-names --crate-type bin --crate-type proc-macro --crate-type rlib --target x86_64-unknown-linux-gnu (exit code: 101) --- stderr error: unknown crate type: proc-macro

My Rust version is 1.13.0 and my Cargo.toml has these dependencies:

[dependencies]
serde = "*"
serde_derive = "*"

Should I use other dependencies or extra configuration?

Answer 1

The #![feature(...)] attribute indicates code that uses Rust features which have not been stabilized yet. At the time the question was asked, the proc_macro feature was not yet stable. Serde needs this feature for its #[derive(Serialize, Deserialize)] macros.

Custom derives have been stabilized as of Rust 1.15 so the code in the question (with the feature attribute removed) should work on any Rust compiler since that version.