no_std is broken

[MarkSwanson]

My Cargo.toml has:
num-traits = { version = ">=0.2.0", default-features = false }

My crate fails to compile when I build it like this:
cargo --verbose build --target thumbv7m-none-eabi

(What confuses me in the output is this --> --cfg 'feature="default"' --cfg 'feature="std"')
(Why is Cargo ignoring: default-features = false ?)

Compiling num-traits v0.2.8
Running rustc --crate-name num_traits /home/mswanson/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/num-traits-0.2.8/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="std"' -C metadata=616873d37e025f24 -C extra-filename=-616873d37e025f24 --out-dir '/mnt/sdb2/@home/mswanson/src/stm32/rust-compression/target/thumbv7m-none-eabi/debug/deps' --target thumbv7m-none-eabi -L 'dependency=/mnt/sdb2/@home/mswanson/src/stm32/rust-compression/target/thumbv7m-none-eabi/debug/deps' -L 'dependency=/mnt/sdb2/@home/mswanson/src/stm32/rust-compression/target/debug/deps' --cap-lints allow --cfg has_i128
error[E0463]: can't find crate for std
--> /home/mswanson/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/num-traits-0.2.8/src/lib.rs:21:1

[CryZe]

It's probably a dev dependency that is using num-traits as well.

[cuviper]

Yes, I think it's an instance of rust-lang/cargo#2589. You could use cargo tree to see where crates are used in your dependency tree, especially inverted like cargo tree -i -p num-traits.

[Sympatron]

This is probably fixed by now. The new resolver should do a better job of resolving things like that and it hasn't come up again for 4 years.