Cannot build basic.rs about examples HOT 2 CLOSED

For anyone who runs into this issue, you need to add an explicit dependency on gio to your Cargo.toml, and import gio::prelude::*. The extern crate statements are no longer required in this case when using Rust 2018 edition.

gtk already depends on gio, however it doesn't re-export the crate so it's unavailable unless you explicitly add a dependency in Cargo.toml. The connect_activate() used in the examples is defined in gio::ApplicationExt, and similarly run() is in gio::ApplicationExtManual, which is why this is needed. As noted in https://gtk-rs.org/docs-src/tutorial/gnome_and_rust you need to explicitly import the traits containing various methods you wish to use, which is why this is needed.

It might be a good idea to re-export dependent crates (like gio, gdk, atk, etc) from gtk to avoid having to explicitly specify these libraries in Cargo.toml. rust-qt apparently does this: "Each crate re-exports its dependencies, so, for example, you can access qt_core as qt_widgets::qt_core without adding an explicit dependency." (https://rust-qt.github.io/qt/getting_started/). This would then allow importing gtk::gio::prelude::* in this example without needing the explicit gio dependency in Cargo.toml. In general unless you're writing library code for one of these layers directly I don't think importing them via gtk would really be an issue.

from examples.

Yeah that would happen if @LucasZanella didn't just get rid of the two extern crate but also the use gio::prelude::*. That one is required for this to work.

Thanks @sagara- !

from examples.