cargo check in the workspace discards crate-specific configurations; such as --target

[WildCryptoFox]

Problem

Running cargo check --all in the root of a workspace discards the per-crate cargo configuration. In my case this results in the [build] target = "xxx" being ignored.

Steps

1. Setup a workspace containing a crate with its own .cargo/config
2. Run cargo check inside that crate's dir. It successfully uses the config.
3. Run cargo check --all from the root of the workspace. It fails to use the config.

Possible Solution(s)

Always use the crate's cargo configuration if it exists.

Notes

Output of cargo version:

I think this is a digression but I haven't verified any older versions worked.

cargo 1.40.0-nightly (5da4b4d47 2019-10-28)

[ehuss]

Thanks for the report! This is a duplicate of #2930, so closing in favor of that. Cargo currently only looks at the current directory and up. It indeed can be surprising, but it is a bit difficult to nail down different rules, and can be tricky with backwards compatibility.