redu fails to build using "cargo install" with default stable toolchain

[eugenesan]

I just tried updating redu using cargo install redu and it fails.

Compiling redu v0.2.12
error[E0554]: `#![feature]` may not be used on the stable release channel
--> /home/eugenesan/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/redu-0.2.12/src/lib.rs:1:1
|
1 | #![feature(exit_status_error)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0554]: `#![feature]` may not be used on the stable release channel
--> /home/eugenesan/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/redu-0.2.12/src/lib.rs:2:1
|
2 | #![feature(step_trait)]
| ^^^^^^^^^^^^^^^^^^^^^^^

error[E0554]: `#![feature]` may not be used on the stable release channel
--> /home/eugenesan/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/redu-0.2.12/src/lib.rs:3:1
|
3 | #![feature(try_blocks)]
| ^^^^^^^^^^^^^^^^^^^^^^^

error[E0554]: `#![feature]` may not be used on the stable release channel
--> /home/eugenesan/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/redu-0.2.12/src/lib.rs:4:1
|
4 | #![feature(iter_intersperse)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For more information about this error, try `rustc --explain E0554`.
error: could not compile `redu` (lib) due to 4 previous errors

Manually switching to nightly toolchain rustup default nightly works but I can't recall doing the switch in the past and I can swear cargo would even pull nightly toolchain if I didn't have one.

Building from source works regardless of which toolchain is the default.
Did recent versions of cargo start to ignore rust-toolchain.toml?

I have the following freshly updated toolchains:

stable-x86_64-unknown-linux-gnu unchanged - rustc 1.86.0 (05f9846f8 2025-03-31)
nightly-x86_64-unknown-linux-gnu updated - rustc 1.88.0-nightly (092a284ba 2025-04-13) (from rustc 1.88.0-nightly (d5b4c2e4f 2025-04-02))

[drdo]

Hello, I've pushed some changes into main (#91) which should allow building with stable Rust. This should get included in the next release.

Thank you for the report :)

[drdo]

Hey, v0.2.13 was just published, could you try upgrading and checking if the problem is gone?

[eugenesan]

@drdo
The new release installs with default stable toolchain without any issues.
Thanks!