"macro undefined" error while compiling hyper 0.9.17

Question

I'm trying to build a web service with Iron using this source as a tutorial, but I'm getting errors during compilation of hyper:

Compiling hyper v0.9.17
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:62:23: 62:30 error: macro undefined: 'langtag!'
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:62                 qitem(langtag!(en;;;US)),
                                                                                                                                 ^~~~~~~
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:63:34: 63:41 error: macro undefined: 'langtag!'
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:63                 QualityItem::new(langtag!(en), Quality(500)),
                                                                                                                                            ^~~~~~~
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:64:23: 64:30 error: macro undefined: 'langtag!'
/root/.cargo/registry/src/github.com-88ac128001ac3a9a/hyper-0.9.17/src/header/common/accept_language.rs:64                 qitem(langtag!(fr)),
                                                                                                                                 ^~~~~~~

Versions I'm using:

cargo 0.8.0 (built 2016-03-22)
rustc 1.7.0

Cargo.toml

[package]
name = "hello"
version = "0.1.0"
authors = ["root"]

[dependencies]
language-tags = "0.2.2"
iron = "0.4.0"

main.rs:

extern crate iron;

use iron::prelude::*;
use iron::status;
use iron::mime::Mime;

fn main() {
  Iron::new(|_: &mut Request| {
  let content_type = "application/json".parse::<Mime>().unwrap();

  Ok(Response::with((content_type, status::Ok, "{ respone: \"Hello world!\" }")))
 }).http("localhost:3009").unwrap();
}

I only added the language-tags in the Cargo.toml because I thought it would be solve my problem. Additional changes were not made.

Why did you choose to use Rust 1.7? That's about 11 months old at this point. — Shepmaster, Jan 28 '17 at 23:15

score 1 · Accepted Answer · edited Jan 29 '17 at 14:19

An old version of Rust was causing the problem. Today's stable version of Rust is 1.14.0, but on my Digital Ocean VM, Rust 1.7 was preinstalled. Even after running the official installer, the version was still 1.7:

curl https://sh.rustup.rs -sSf | sh

After the installation it says:

Welcome to Rust!

This will download and install the official compiler for the Rust programming language, and its package manager, Cargo.

It will add the cargo, rustc, rustup and other commands to Cargo's bin directory, located at:
/root/.cargo/bin
This path will then be added to your PATH environment variable by modifying the profile file located at:
/root/.profile

I use zsh which doesn't use ~/.profile. So the PATH environment variable wasn't changed for me and therefor the command cargo run pointed to the preinstalled old version in /usr/bin/cargo and not to ~/.cargo/bin.

You can find out where the executables are located with the command which cargo or which rustc.

The solution was to use ~/.cargo/bin/cargo run. For zsh, you can also add the folder ~/.cargo/binto your PATH environment variable by adding

export PATH="~/.cargo/bin:$PATH"

to your .zshrc

I'm pretty sure if you kept reading the installation text, [you would have seen](https://github.com/rust-lang-nursery/rustup.rs/blob/dcacbf6ed229ce96a86894011c11f28838df0979/src/rustup-cli/self_update.rs#L115-L119): *Next time you log in this will be done automatically. **To configure your current shell** run `source {cargo_home}/env`*. — Shepmaster, Jan 29 '17 at 14:22

"macro undefined" error while compiling hyper 0.9.17

1 Answers1