Can't build package from crates.io registry

[jkopanski]

I've prepared minimal repository

nix build fails with building the dependency cairo-lang-casm, in a code that is behind an enabled feature flag, with a message:

error: Could not find `parity-scale-codec` in `dependencies` or `dev-dependencies` in `/home/nat/famisoft/cargo2nix-issue/debug/cairo-lang-casm-2.6.3/Cargo.toml`!
  --> src/hints/mod.rs:24:12
   |
24 |     derive(parity_scale_codec::Encode, parity_scale_codec::De...
   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |

You can see the failed build in the github CI run here.

I don't know how cargo2nix should work, but I've followed this guide to take a peek what's going on. Very neat feature, btw. I didn't know this. Indeed cairo2nix overwrites Cargo.toml to

[package]
edition = "2021"
name = "cairo-lang-casm"
version = "2.6.3"
description = "Cairo assembly encoding."
license-file = "LICENSE"
repository = "https://github.com/starkware-libs/cairo/"

[features]
default = []
parity-scale-codec = []
serde = []
std = []

[profile]

which indeed doesn't have dependencies section. I guess cargo2nix uses compiler flags to pass them instead. However cairo-lang-casm entry from Cargo.nix seems to list proper dependency.

cargo build builds successfully when executed from the nix shell.

I don't know if this is some sort of bug, or perhaps I am doing something wrong here? Please advise.