CARGO-FIX(1)

📦 version 1.88.0, in ubuntu questing

💖 CARGO-FIX(1) 💖

okay bestie you just opened the General Commands Manual and landed on CARGO-FIX(1) — congrats, you're in exactly the right place 💅 let's get into it

🌸 NAME 🌸

cargo-fix — automatically fix lint warnings reported by rustc ✨

🌸 SYNOPSIS 🌸

cargo fix [options]

🌸 DESCRIPTION 🌸

okay so the whole vibe here: this Cargo subcommand grabs rustc's suggestions straight out of diagnostics like warnings and just applies them to your source code for you 🫶 it exists to automate the stuff rustc already knows how to tell you to fix — no cap, it literally does the homework the compiler was already assigning.

When you run cargo fix, under the hood it runs cargo-check(1). Every warning that applies to your crate gets fixed automatically (if it can be fixed), and all the warnings that are still hanging around get shown to you once the check process finishes. So like, if you wanna apply every fix to the current package, you just run:

cargo fix

which behaves the same as cargo check --all-targets.

Important caveat time, bestie: cargo fix is only capable of fixing code that is normally compiled with cargo check. So if some code is conditionally enabled with optional features, you need to turn those features on for that code to even get analyzed:

cargo fix --features foo

Same energy for other cfg expressions — like platform-specific code — you'll need to pass --target to fix code for the given target:

cargo fix --target x86_64-pc-windows-gnu

And if you hit any problems with cargo fix, or you've got questions, or feature requests — please don't hesitate to file an issue at <https://github.com/rust-lang/cargo> 💌

🧚 Edition migration 🧚

the cargo fix subcommand can also be used to migrate a package from one edition <https://doc.rust-lang.org/edition-guide/editions/transitioning-an-existing-project-to-a-new-edition.html> to the next one. The general procedure goes like this:

  1. Run cargo fix --edition. Consider also using the --all-features flag if your project has multiple features. You may also want to run cargo fix --edition multiple times with different --target flags if your project has platform-specific code gated by cfg attributes.
  2. Modify Cargo.toml to set the edition field <https://doc.rust-lang.org/cargo/reference/manifest.html#the-edition-field> to the new edition.
  3. Run your project tests to verify that everything still works. If new warnings are issued, you may want to consider running cargo fix again (without the --edition flag) to apply any suggestions given by the compiler.

And hopefully that's it! 🎉 Just keep in mind those caveats from above — cargo fix cannot update code for inactive features or cfg expressions. Also, in some rare cases the compiler is unable to automatically migrate all code to the new edition, and that may require manual changes after building with the new edition. Not a bug, just the way it is, fr fr.

✨ OPTIONS ✨

🔧 Fix options 🔧

  • --broken-code — Fix code even if it already has compiler errors. This is useful if cargo fix fails to apply the changes. It will apply the changes and leave the broken code in the working directory for you to inspect and manually fix. (yes it's literally leaving broken code behind on purpose, go look at it 👀)
  • --edition — Apply changes that will update the code to the next edition. This will not update the edition in the Cargo.toml manifest — that you have to update manually after cargo fix --edition has finished. 💅
  • --edition-idioms — Apply suggestions that will update code to the preferred style for the current edition.
  • --allow-no-vcs — Fix code even if a VCS was not detected.
  • --allow-dirty — Fix code even if the working directory has changes (including staged changes).
  • --allow-staged — Fix code even if the working directory has staged changes.

📦 Package Selection 📦

By default, when no package selection options are given, the packages selected depend on the selected manifest file (based on the current working directory if --manifest-path is not given). If the manifest is the root of a workspace then the workspace's default members are selected, otherwise only the package defined by the manifest will be selected.

The default members of a workspace can be set explicitly with the workspace.default-members key in the root manifest. If this is not set, a virtual workspace will include all workspace members (equivalent to passing --workspace), and a non-virtual workspace will include only the root crate itself.

  • -p *spec*…, --package *spec*… — Fix only the specified packages. See cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and []. However, to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each pattern. (quote your globs, bestie, the shell is feral 🙈)
  • --workspace — Fix all members in the workspace.
  • --all — Deprecated alias for --workspace.
  • --exclude *SPEC*… — Exclude the specified packages. Must be used in conjunction with the --workspace flag. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and []. However, to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each pattern.

🎯 Target Selection 🎯

When no target selection options are given, cargo fix will fix all targets (--all-targets implied). Binaries are skipped if they have required-features that are missing.

Passing target selection flags will fix only the specified targets.

Note that --bin, --example, --test and --bench flags also support common Unix glob patterns like *, ? and []. However, to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each glob pattern.

  • --lib — Fix the package's library.
  • --bin *name*… — Fix the specified binary. This flag may be specified multiple times and supports common Unix glob patterns.
  • --bins — Fix all binary targets.
  • --example *name*… — Fix the specified example. This flag may be specified multiple times and supports common Unix glob patterns.
  • --examples — Fix all example targets.
  • --test *name*… — Fix the specified integration test. This flag may be specified multiple times and supports common Unix glob patterns.
  • --tests — Fix all targets that have the test = true manifest flag set. By default this includes the library and binaries built as unittests, and integration tests. Be aware that this will also build any required dependencies, so the lib target may be built twice (once as a unittest, and once as a dependency for binaries, integration tests, etc.). Targets may be enabled or disabled by setting the test flag in the manifest settings for the target.
  • --bench *name*… — Fix the specified benchmark. This flag may be specified multiple times and supports common Unix glob patterns.
  • --benches — Fix all targets that have the bench = true manifest flag set. By default this includes the library and binaries built as benchmarks, and bench targets. Be aware that this will also build any required dependencies, so the lib target may be built twice (once as a benchmark, and once as a dependency for binaries, benchmarks, etc.). Targets may be enabled or disabled by setting the bench flag in the manifest settings for the target.
  • --all-targets — Fix all targets. This is equivalent to specifying --lib --bins --tests --benches --examples.

🌈 Feature Selection 🌈

The feature flags let you control which features are enabled. When no feature options are given, the default feature is activated for every selected package.

See the features documentation <https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options> for more details.

  • -F features, --features features — Space or comma separated list of features to activate. Features of workspace members may be enabled with package-name/feature-name syntax. This flag may be specified multiple times, which enables all specified features.
  • --all-features — Activate all available features of all selected packages.
  • --no-default-features — Do not activate the default feature of the selected packages.

⚙️ Compilation Options ⚙️

  • --target triple — Fix for the given architecture. The default is the host architecture. The general format of the triple is <arch><sub>-<vendor>-<sys>-<abi>. Run rustc --print target-list for a list of supported targets. This flag may be specified multiple times.

This may also be specified with the build.target config value <https://doc.rust-lang.org/cargo/reference/config.html>.

Note that specifying this flag makes Cargo run in a different mode where the target artifacts are placed in a separate directory. See the build cache <https://doc.rust-lang.org/cargo/reference/build-cache.html> documentation for more details.

  • -r, --release — Fix optimized artifacts with the release profile. See also the --profile option for choosing a specific profile by name.
  • --profile name — Fix with the given profile.

As a special case, specifying the test profile will also enable checking in test mode which will enable checking tests and enable the test cfg option. See rustc tests <https://doc.rust-lang.org/rustc/tests/index.html> for more detail.

See the reference <https://doc.rust-lang.org/cargo/reference/profiles.html> for more details on profiles.

  • --timings=fmts — Output information how long each compilation takes, and track concurrency information over time. Accepts an optional comma-separated list of output formats; --timings without an argument will default to --timings=html. Specifying an output format (rather than the default) is unstable and requires -Zunstable-options. Valid output formats:
    • html (unstable, requires -Zunstable-options): Write a human-readable file cargo-timing.html to the target/cargo-timings directory with a report of the compilation. Also write a report to the same directory with a timestamp in the filename if you want to look at older runs. HTML output is suitable for human consumption only, and does not provide machine-readable timing data.
    • json (unstable, requires -Zunstable-options): Emit machine-readable JSON information about timing information.

📁 Output Options 📁

  • --target-dir directory — Directory for all generated artifacts and intermediate files. May also be specified with the CARGO_TARGET_DIR environment variable, or the build.target-dir config value <https://doc.rust-lang.org/cargo/reference/config.html>. Defaults to target in the root of the workspace.

✨ Display Options ✨

okay bestie, these control what Cargo yells at you and how cute it looks doing it 💅

  • -v, --verbose — Spill the tea, Cargo. Use verbose output. You can say it twice for “very verbose” output, which includes extra stuff like dependency warnings and build script output. May also be set with the term.verbose config value (https://doc.rust-lang.org/cargo/reference/config.html).
  • -q, --quiet — Shhh, no thoughts, just vibes. Do not print cargo log messages. May also be set with the term.quiet config value (https://doc.rust-lang.org/cargo/reference/config.html).
  • --color when — Controls when colored output is used. Valid values are giving:
    • auto (default): Automatically detect if color support is available on the terminal.
    • always: Always display colors.
    • never: Never display colors.

May also be set with the term.color config value (https://doc.rust-lang.org/cargo/reference/config.html).

  • --message-format fmt — The output format for diagnostic messages. Can be specified multiple times and consists of comma-separated values. Valid values:
    • human (default): Display in a human-readable text format. Conflicts with short and json.
    • short: Emit shorter, human-readable text messages. Conflicts with human and json.
    • json: Emit JSON messages to stdout. See the reference (https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages) for more details. Conflicts with human and short.
    • json-diagnostic-short: Ensure the rendered field of JSON messages contains the “short” rendering from rustc. Cannot be used with human or short.
    • json-diagnostic-rendered-ansi: Ensure the rendered field of JSON messages contains embedded ANSI color codes for respecting rustc’s default color scheme. Cannot be used with human or short.
    • json-render-diagnostics: Instruct Cargo to not include rustc diagnostics in JSON messages printed, but instead Cargo itself should render the JSON diagnostics coming from rustc. Cargo’s own JSON diagnostics and others coming from rustc are still emitted. Cannot be used with human or short.

🌸 Manifest Options 🌸

these are the "where is my Cargo.toml" and "lock it down" options, periodt.

  • --manifest-path path — Path to the Cargo.toml file. By default, Cargo searches for the Cargo.toml file in the current directory or any parent directory.
  • --ignore-rust-version — Ignore rust-version specification in packages. Not me ignoring the version like it's an ex's text.
  • --locked — Asserts that the exact same dependencies and versions are used as when the existing Cargo.lock file was originally generated. Cargo will exit with an error when either of the following scenarios arises:
    • The lock file is missing.
    • Cargo attempted to change the lock file due to a different dependency resolution.

It may be used in environments where deterministic builds are desired, such as in CI pipelines.

  • --offline — Prevents Cargo from accessing the network for any reason. Without this flag, Cargo will stop with an error if it needs to access the network and the network is not available. With this flag, Cargo will attempt to proceed without the network if possible.
Beware bestie: this may result in different dependency resolution than online mode. Cargo will restrict itself to crates that are downloaded locally, even if there might be a newer version as indicated in the local copy of the index. See the cargo-fetch(1) command to download dependencies before going offline.

May also be specified with the net.offline config value (https://doc.rust-lang.org/cargo/reference/config.html).

  • --frozen — Equivalent to specifying both --locked and --offline. Two-for-one slay.
  • --lockfile-path PATH — Changes the path of the lockfile from the default (<workspace_root>/Cargo.lock) to PATH. PATH must end with Cargo.lock (e.g. --lockfile-path /tmp/temporary-lockfile/Cargo.lock). Note that providing --lockfile-path will ignore existing lockfile at the default path, and instead will either use the lockfile from PATH, or write a new lockfile into the provided PATH if it doesn’t exist. This flag can be used to run most commands in read-only directories, writing lockfile into the provided PATH.
This option is only available on the nightly channel (https://doc.rust-lang.org/book/appendix-07-nightly-rust.html) and requires the -Z unstable-options flag to enable (see #14421 https://github.com/rust-lang/cargo/issues/14421).

🦋 Common Options 🦋

the everyday besties that show up to every cargo command.

  • +toolchain — If Cargo has been installed with rustup, and the first argument to cargo begins with +, it will be interpreted as a rustup toolchain name (such as +stable or +nightly). See the rustup documentation (https://rust-lang.github.io/rustup/overrides.html) for more information about how toolchain overrides work.
  • --config KEY=VALUE or PATH — Overrides a Cargo configuration value. The argument should be in TOML syntax of KEY=VALUE, or provided as a path to an extra configuration file. This flag may be specified multiple times. See the command-line overrides section (https://doc.rust-lang.org/cargo/reference/config.html#command-line-overrides) for more information.
  • -C PATH — Changes the current working directory before executing any specified operations. This affects things like where cargo looks by default for the project manifest (Cargo.toml), as well as the directories searched for discovering .cargo/config.toml, for example. This option must appear before the command name, for example cargo -C path/to/my-project build.
This option is only available on the nightly channel (https://doc.rust-lang.org/book/appendix-07-nightly-rust.html) and requires the -Z unstable-options flag to enable (see #10098 https://github.com/rust-lang/cargo/issues/10098).
  • -h, --help — Prints help information. When in doubt, ask for help. Iconic.
  • -Z flag — Unstable (nightly-only) flags to Cargo. Run cargo -Z help for details. Nightly only, bestie — not for the faint of heart.

💖 Miscellaneous Options 💖

  • -j N, --jobs N — Number of parallel jobs to run. May also be specified with the build.jobs config value (https://doc.rust-lang.org/cargo/reference/config.html). Defaults to the number of logical CPUs. If negative, it sets the maximum number of parallel jobs to the number of logical CPUs plus provided value. If a string default is provided, it sets the value back to defaults. Should not be 0.
  • --keep-going — Build as many crates in the dependency graph as possible, rather than aborting the build on the first one that fails to build.

For example if the current package depends on dependencies fails and works, one of which fails to build, cargo fix -j1 may or may not build the one that succeeds (depending on which one of the two builds Cargo picked to run first), whereas cargo fix -j1 --keep-going would definitely run both builds, even if the one run first fails.

🌈 ENVIRONMENT 🌈

See the reference (https://doc.rust-lang.org/cargo/reference/environment-variables.html) for details on environment variables that Cargo reads. Yes, Cargo reads env vars. Yes, it's that kind of relationship.

✨ EXIT STATUS ✨

  • 0: Cargo succeeded. We love a success story.
  • 101: Cargo failed to complete. Oop. Not the 101.

🎀 EXAMPLES 🎀

  1. Apply compiler suggestions to the local package:
cargo fix
  1. Update a package to prepare it for the next edition:
cargo fix --edition
  1. Apply suggested idioms for the current edition:
cargo fix --edition-idioms

💅 SEE ALSO 💅

cargo(1), cargo-check(1)

That's the whole CARGO-FIX(1) page, bestie — go fix ur code with main character energy fr fr. 💖✨

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