cargo build failed on non-related platform dependency

[cathay4t]

Problem

The cargo vendor will include all dependency regardless platform. After removed the windows dependency,
the cargo build will fail on missing dependency even compiling on unix.

Steps

cargo new bug_test
cd bug_test
mkdir .cargo
echo '[source.crates-io]
replace-with = "vendored-sources"

[source.vendored-sources]
directory = "vendor"' > .cargo/config

echo '[target."cfg(windows)".dependencies.winapi]
version = "0.3"' >> Cargo.toml
cargo build

Possible Solution(s)

No idea

Notes

Output of cargo version: cargo 1.47.0 (f3c7e06 2020-08-28)

[cathay4t]

This might related to #7058 where people are requesting cargo vendor --platform unix.

[ehuss]

Yea, I'm going to close this as a duplicate of #7058 (and related to #5133). The resolver needs all dependencies regardless of platform, so it is expected that it will fail.