Without this:
error: failed to select a version for `serde_test_suite`.
... required by package `serde_test_suite-tests v0.0.0`
versions that meet the requirements `= 0.0.0` are: 0.0.0
the package `serde_test_suite-tests` depends on `serde_test_suite`, with features: `serde` but `serde_test_suite` does not have these features.
failed to select a version for `serde_test_suite` which could resolve this conflict
Seems like a Cargo bug -- I will minimize and report.
1e9ae88f53