{"id":306,"hash":"ca1745d0f922d8aef8d5dc0633e5974e16f9052a2c3c8f38de98ebcec24df5b2","pattern":"error[E0554]: #![feature] may not be used on the stable release channel Couldn't install racer using cargo","full_message":"I'm trying to install racer using cargo, so I executed the command cargo install racer in the terminal and  it resulted in the error:\n\nerror[E0554]: #![feature] may not be used on the stable release channel\n--> /home/rajkumar/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:47:34\n|\n47 | #![cfg_attr(feature = \"nightly\", feature(macro_vis_matcher))]\n|                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\nerror[E0554]: #![feature] may not be used on the stable release channel\n--> /home/rajkumar/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:48:34\n|\n48 | #![cfg_attr(feature = \"nightly\", feature(allow_internal_unstable))]\n|                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\nerror: aborting due to 2 previous errors\n\nFor more information about this error, try `rustc --explain E0554`.\nerror: failed to compile `racer v2.1.10`, intermediate artifacts can be found at `/tmp/cargo-install5YWPWW`\n\nCaused by:\nCould not compile `scoped-tls`.\n\nTo learn more, run the command again with --verbose.\n\nBelow are my Rust details:\n\n$rustc --version\nrustc 1.30.0 (da5f414c2 2018-10-24)\n\n> rustup --version \nrustup 1.14.0 (1e51b07cc 2018-10-04)\n\n> cargo --version \ncargo 1.30.0 (36d96825d 2018-10-24)\n\nBelow is my opensuse version details:\n\n> cat /usr/lib/os-release \nNAME=\"openSUSE Tumbleweed\"\n# VERSION=\"20181029\"\nID=\"opensuse-tumbleweed\"\nID_LIKE=\"opensuse suse\"\nVERSION_ID=\"20181029\"\nPRETTY_NAME=\"openSUSE Tumbleweed\"\nANSI_COLOR=\"0;32\"\nCPE_NAME=\"cpe:/o:opensuse:tumbleweed:20181029\"\nBUG_REPORT_URL=\"https://bugs.opensuse.org\"\nHOME_URL=\"https://www.opensuse.org/\"\n\nWhy am I not able to install racer using cargo? Am I missing anything?","ecosystem":"cargo","package_name":"rust-cargo","package_version":null,"solution":"As the error message states, you cannot compile that code with stable Rust. You need to install nightly Rust and then use it to compile the program:\n\nrustup install nightly\ncargo +nightly install racer\n\nSee also:\n\nHow to execute cargo test using the nightly channel?\nIs it possible to have multiple coexisting Rust installations?\nRocket requires a minimum version of Rust nightly, but a higher stable version is already installed","confidence":0.95,"source":"stackoverflow","source_url":"https://stackoverflow.com/questions/53136717/errore0554-feature-may-not-be-used-on-the-stable-release-channel-couldnt","votes":117,"created_at":"2026-04-19T04:41:50.434057+00:00","updated_at":"2026-04-19T04:52:30.363891+00:00"}