How do I use clap 4.0.0-rc.3?

help
1

https://crates.io/crates/clap/versions lists 4.0.0.-rc.3 as the latest version of clap, but when I add clap = "4.0.0-rc.3" to the [dependencies] section of Cargo.toml and run cargo build, it says:

$ cargo build
    Updating crates.io index
error: failed to select a version for the requirement `clap = "^4.0.0-rc.3"`
candidate versions found which didn't match: 3.2.22, 3.2.21, 3.2.20, ...
location searched: crates.io index

How can I use this version?

2

You must update Rust to 1.60 or later. Run rustup update. If you got your Rust from a Linux distribution, uninstall it, and install from https://rustup.rs.

Older versions of Rust won't "see" versions of crates that use new dependency syntax added in 1.60.

4 Likes
3

I am using

clap = { version = "4.0.0-rc.1", features = ["derive"] }
4

Weird. I copied and pasted that in my Cargo.toml, but I still see a similar error:

$ cargo build
    Updating crates.io index
error: failed to select a version for the requirement `clap = "^4.0.0-rc.1"`
candidate versions found which didn't match: 3.2.22, 3.2.21, 3.2.20, ...
location searched: crates.io index

I'm using cargo 1.57.0. Which version are you using?

5

Ah, thank you both for your help. I'll try to upgrade Rust.

6

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