[patch] in config.toml triggers unhelpful warnings #11782
Description
Problem
#9269 introduced [patch] in .cargo/config.toml. If dependencies patched in this way are used in some workspaces but not others, unnecessary warnings are emitted:
warning: Patch `headless_chrome v0.9.0 (https://github.com/alecmocatta/rust-headless-chrome#db63e48b)` was not used in the crate graph.
Patch `optional_struct v0.2.0 (https://github.com/alecmocatta/OptionalStruct#58d1f03a)` was not used in the crate graph.
Patch `tokio-tar v0.3.0 (https://github.com/alecmocatta/tokio-tar#01af794b)` was not used in the crate graph.
Check that the patched package version and available features are compatible
with the dependency requirements. If the patch has a different version from
what is locked in the Cargo.lock file, run `cargo update` to use the new
version. This may also occur with an optional dependency that is not enabled.
We use the xtask pattern, with workspaces for different targets.
Possible Solution(s)
Silence warnings about unused patches that come from config.tomls
Version
cargo 1.65.0-nightly (efd4ca3dc 2022-08-12)