cargo no-std-check is a wrapper for cargo check, which ensures that your
library does not link against libstd.
cargo no-std-check can be built with any stable version of rust, but its
operation requires a nightly compiler.
$ cargo install cargo-no-std-check
Run this command on a crate to build it's lib target without access to std.
Attempts to use std in the final library's dependency hierarchy will produce a
build error.
$ cargo no-std-check --manifest-path nostd/Cargo.toml
Creating #![no_std] sysroot
Copying [============================================================] 154/154: done
Sysroot x86_64-unknown-linux-gnu (/tmp/nostd_sysroot.YhFkabJ2tXeK)
Finished dev [unoptimized + debuginfo] target(s) in 0.01s
``
$ cargo no-std-check --manifest-path withstd/Cargo.toml
Creating #![no_std] sysroot
Copying [============================================================] 154/154: done
Sysroot x86_64-unknown-linux-gnu (/tmp/nostd_sysroot.uYDnxo4ZNOLs)
Checking withstd v0.1.0 (/crates/withstd)
error[E0463]: can't find crate forstd`
error: aborting due to previous error
For more information about this error, try rustc --explain E0463.
error: could not compile withstd.
To learn more, run the command again with --verbose. ```