Remove unused `rustc_trait_selection` dependencies Found using `cargo-machete`. The `bitflags` and `derivative` crates were added for the new trait solver, but weren't removed when the next trait solver code was uplifted to a separate crate.
Remove unused `rustc_trait_selection` dependencies Found using `cargo-machete`. The `bitflags` and `derivative` crates were added for the new trait solver, but weren't removed when the next trait solver code was uplifted to a separate crate.