Tracking Issue for per-package-target

[Ekleog]

Summary

Feature gate: per_package_target
Discussion: https://internals.rust-lang.org/t/proposal-move-some-cargo-config-settings-to-cargo-toml/13336
Implementation: #9030
Documentation: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#per-package-target
Issues: Z-per-package-target Nightly: per-package-target

Unresolved issues

• The interaction with proposals like RFC 3028 does not work well. Selection for targets to build happens at the workspace level instead of at a level where the full compile graph is known. This affects selected packages (target-specific dependencies) and feature resolution as well. There's also some possible confusion, as the per-package-target settings are ignored in dependencies.
• The exact interaction with feature resolution is a bit up in the air. This may not be super well-tested where in theory each target artifact should get an independently resolved feature graph (ish). Related to: per-package-target unifies features which can conflict with other targets #9521
• Interaction with -Zbuild-std

[MarkSwanson]

#9521
I'm not sure if I should place this here. Just trying to help with keeping track...

[FrankvdStam]

See #9537

[Airtz]

Another issue is the interaction with -Zmultitarget #8176

IMO we should be able to do the following:

[package]
forced-target = ["x86_64-pc-windows-msvc", "i686-pc-windows-msvc"]