Hamzeh,

Hamzeh Nasajpour 写道：
> As you can see, the `rust` path is available in the `PATH`. I 
> get the list of this path:
> ```
> $ ls 
> /gnu/store/axjq514q8gqk90hi7r7wpfbba3id6h18-rust-1.39.0/bin/
> rustc  rustdoc  rust-gdb  rust-gdbgui  rust-lldb
> ```
>
> I couldn't see the `cargo`. I also couldn't find any package for 
> installing the `cargo`.

You're missing the rust:cargo output that provides ‘cargo’:

  ~ λ guix build rust
  ...
  /gnu/store/a5dmqx64mg8jq5s9ffrp4vwhmw3wjjdg-rust-1.46.0-cargo
  /gnu/store/4szzm4wlbrpspc7xi8vqx4hckazqn78i-rust-1.46.0-doc
  /gnu/store/hq4ni80kwx1cj6vyx35ljzr092xgvxca-rust-1.46.0

I.e.:

  (native-inputs
   `(...
     ("rust:cargo" ,rust "cargo")
     ...))

Kind regards,

T G-R