cargo-report

cargo report type [options]

cargo report generates diagnostic reports about the project. Currently its primary subcommand is `future-incompatibilities`, which displays warnings about code patterns in dependencies that will be rejected in future Rust versions.When Cargo detects future-incompatible warnings during a build, it stores a report and displays a notification with instructions to view the full details. These warnings indicate patterns that may exhibit undefined behavior, are scheduled for removal, or lack well-defined semantics. Reviewing these reports helps maintainers proactively update their dependencies before breaking changes land.

--id id

Report ID from previous build

Package to report on

Verbose output

Suppress output

.cargo/config.toml

Controls report frequency via `[future-incompat-report]` section (e.g., `frequency = "always"`).

future-incompatibilities

Display future incompatibility report

Cargo checks dependencies for patterns that:- May exhibit undefined behavior- Are scheduled for removal from Rust- Do not have well-defined semanticsWhen detected, a warning appears after build with instructions to view the full report.

1. Update dependencies to versions with fixes2. Work with dependency maintainers3. Consider alternatives if unmaintained

Report is not a lint and doesn't interact with -Dwarnings. These warnings don't fail builds but indicate future breakage.

cargo(1), cargo-build(1)

Source code · Documentation