#cargo #no-std #nono #subcommand

no-std app cargo-nono

Detect (possible) no_std compatibility of your crate and dependencies

10 releases

0.1.9 Sep 27, 2020
0.1.8 Jan 8, 2020
0.1.6 Sep 10, 2019
0.1.5 Jun 29, 2019
0.1.2 Nov 16, 2018

#325 in Cargo plugins

Download history 28/week @ 2023-10-28 2/week @ 2023-11-04 16/week @ 2023-11-11 81/week @ 2023-11-18 97/week @ 2023-11-25 32/week @ 2023-12-02 57/week @ 2023-12-09 12/week @ 2023-12-16 24/week @ 2023-12-23 15/week @ 2023-12-30 3/week @ 2024-01-06 4/week @ 2024-01-13 17/week @ 2024-01-20 46/week @ 2024-01-27 10/week @ 2024-02-03 40/week @ 2024-02-10

115 downloads per month



Contains (Mach-o exe, 1.5MB) crate_itself_fixed_no_std-2702d7a9e7ab9d0b, (Mach-o exe, 590KB) crate_itself_fixed_no_std, (Mach-o exe, 1MB) verify_dependency_with_std-8cdf0632c65e0c89, (Mach-o exe, 1MB) verify_dependency_with_std-8cdf0632c65e0c89, (Mach-o exe, 285KB) detect_explicit_use_std, (rust library, 295KB) libverify_dependency_with_std-9585336dd8a289b9.rlib and 77 more.

cargo nono - Detect (possible) no_std compatibility of your crate and dependencies


From embedded programming, over smart contracts in Rust, to general cross-platform portable crates, #![no_std] crates are becoming more and more widespread. However it is currently a very cumbersome process to find out if and why (not) a crate is compatible with no_std usage, and often requires a lengthy trial and error process, and digging through the source of all your dependencies.

cargo nono tries to aid you in navigating the current minefield that is no_std usage, and it's biggest "no no"s.


Prebuilt binaries

cargo-nono also comes as prebuilt binaries (useful for CI):

curl -LSfs https://japaric.github.io/trust/install.sh | \
    sh -s -- --git hobofan/cargo-nono

From crates.io

cargo install cargo-nono
# For warnings with more informative messages install like this
RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-nono




Run in the crate directory you want to check:

cargo nono check

The cargo nono check subcommand also understands the --no-default-features and --features <FEATURES> flags to help in conditional no_std setups.


  • Tries to infer no_std compatibility in dependencies by looking for a #![no_std] attribute or the often used conditional #![cfg_attr(not(feature = "std"), no_std)]
  • Helps in pinpointing which dependencies and feature flags activate std feature flags
  • Warn of use std:: statements in code

Planned features

  • Warn of [build-dependencies] features bleeding over: cargo#5730


Licensed under either of

at your option.


~113K SLoC