Can't compile in no std environment

[samuel-schuepbach]

I tried using the graphlib on a embedded project I'm working on, but failed to compile it due to dependencies to the std crate.

For reproducibility, I set up the environment the same as described in the embedded rust book: https://docs.rust-embedded.org/book/start/qemu.html

The std features should be disabled:

[dependencies]
graphlib = {version = "0.6.1", features = ["no_std"]}

When compiled with:

cargo +nightly build --target thumbv7m-none-eabi

I got the following error:

   Compiling lazy_static v1.4.0
   Compiling hex v0.4.2
   Compiling num_cpus v1.12.0
   Compiling ahash v0.2.18
error[E0463]: can't find crate for `std`
  |
  = note: the `thumbv7m-none-eabi` target may not be installed

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error[E0463]: can't find crate for `std`
  |
  = note: the `thumbv7m-none-eabi` target may not be installed

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error: could not compile `hex`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: could not compile `num_cpus`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error[E0463]: can't find crate for `std`
 --> /Users/schuepbs/.cargo/registry/src/github.com-1ecc6299db9ec823/lazy_static-1.4.0/src/inline_lazy.rs:9:1
  |
9 | extern crate std;
  | ^^^^^^^^^^^^^^^^^ can't find crate
  |
  = note: the `thumbv7m-none-eabi` target may not be installed

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error: could not compile `lazy_static`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

I believe that this is due to a dependency in the hashbrow crate.
Do you know anything about this?

[samuel-schuepbach]

Update

This problem has been discussed in the hashbrown issue page: rust-lang/hashbrown#124

[octavonce]

@rockresu Thank you for opening this! This should be fixed by simply updating the hashbrown crate. I will do this in the next few days.

[octavonce]

@samuel-schuepbach I have just published a new release which fixes this issue.

[samuel-schuepbach]

@octavonce Great! Thank you for the quick fix!