error[E0658]: arbitrary expressions in key-value attributes are unstable

[flavv]

$ cargo install rust-script
Updating crates.io index
[...]
[...]
Compiling env_logger v0.9.0
Compiling clap_derive v3.0.0-beta.5
Compiling clap v3.0.0-beta.5
error[E0658]: arbitrary expressions in key-value attributes are unstable
--> /home/flav/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-3.0.0-beta.5/src/lib.rs:8:10
|
8 | #![doc = include_str!("../README.md")]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #78835 rust-lang/rust#78835 for more information

error: aborting due to previous error

For more information about this error, try rustc --explain E0658.
error: could not compile clap

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: failed to compile rust-script v0.18.0, intermediate artifacts can be found at /tmp/cargo-installAqSpQJ

Caused by:
build failed

[fornwall]

Hm, seems to be that the latest clap 3 beta requires rust 1.54 (due to extended_key_value_attributes becoming stable there) - see clap-rs/clap#2741.

I'm thinking we need to state and bump our MSRV (Minimum Supported Rust Version) to 1.54 - will that be a problem for you, @flavv, or will you be able to update? If possible, using rustup should make updating smooth.

[fornwall]

Let's go for 1.54 as minimum supported rust version (MSRV) - I've added that information in the README now.

[flavv]

$ rustc --version
rustc 1.57.0 (f1edd0429 2021-11-29)

$ echo 'println!("Hello, World!");' > hello.rs
$ rust-script hello.rs
Hello, World!

it works fine !