fix - The Cargo Book

# cargo fix

## NAME

cargo-fix - Automatically fix lint warnings reported by rustc

## SYNOPSIS

`cargo fix [OPTIONS]`

## DESCRIPTION

This Cargo subcommand will automatically take rustc’s suggestions from diagnostics like warnings and apply them to your source code. This is intended to help automate tasks that rustc itself already knows how to tell you to fix! The `cargo fix` subcommand is also being developed for the Rust 2018 edition to provide code the ability to easily opt-in to the new edition without having to worry about any breakage.

Executing `cargo fix` will under the hood execute cargo-check(1). Any warnings applicable to your crate will be automatically fixed (if possible) and all remaining warnings will be displayed when the check process is finished. For example if you’d like to prepare for the 2018 edition, you can do so by executing:

    cargo fix --edition

which behaves the same as `cargo check --all-targets`. Similarly if you’d like to fix code for different platforms you can do:

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

or if your crate has optional features:

    cargo fix --edition --no-default-features --features foo

If you encounter any problems with `cargo fix` or otherwise have any questions or feature requests please don’t hesitate to file an issue at https://github.com/rust-lang/cargo

## 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.

--edition

  Apply changes that will update the code to the latest edition. This will not update the edition in the `Cargo.toml` manifest, which must be updated manually.

--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.

--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 current working directory. In the root of a virtual workspace, all workspace members are selected (`--all` is implied). Otherwise, only the package in the current directory will be selected. The default packages may be overridden with the `workspace.default-members` key in the root `Cargo.toml` manifest.

-p SPEC…​
--package SPEC…​

  Fix only the specified packages. See cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times.

--all

  Fix all members in the workspace.

--exclude SPEC…​

  Exclude the specified packages. Must be used in conjunction with the `--all` flag. This flag may be specified multiple times.

### 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.

--lib

  Fix the package’s library.

--bin NAME…​

  Fix the specified binary. This flag may be specified multiple times.

--bins

  Fix all binary targets.

--example NAME…​

  Fix the specified example. This flag may be specified multiple times.

--examples

  Fix all example targets.

--test NAME…​

  Fix the specified integration test. This flag may be specified multiple times.

--tests

  Fix all targets in test mode 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.

--benches

  Fix all targets in benchmark mode 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

When no feature options are given, the `default` feature is activated for every selected package.

--features FEATURES

  Space or comma separated list of features to activate. These features only apply to the current directory’s package. Features of direct dependencies may be enabled with `<dep-name>/<feature-name>` syntax.

--all-features

  Activate all available features of all selected packages.

--no-default-features

  Do not activate the `default` feature of the current directory’s package.

### 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 may also be specified with the `build.target` config value.

--release

  Fix optimized artifacts with the `release` profile. See the PROFILES section for details on how this affects profile selection.

--profile NAME

  Changes fix behavior. Currently only `test` is supported, which will fix with the `#[cfg(test)]` attribute enabled. This is useful to have it fix unit tests which are usually excluded via the `cfg` attribute. This does not change the actual profile used.

### 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. Defaults to `target` in the root of the workspace.

### Display Options

-v
--verbose

  Use verbose output. May be specified twice for "very verbose" output which includes extra output such as dependency warnings and build script output. May also be specified with the `term.verbose` config value.

-q
--quiet

  No output printed to stdout.

--color WHEN

  Control when colored output is used. Valid values:

  - `auto` (default): Automatically detect if color support is available on the terminal.

  - `always`: Always display colors.

  - `never`: Never display colors.

  May also be specified with the `term.color` config value.

--message-format FMT

  The output format for diagnostic messages. Valid values:

  - `human` (default): Display in a human-readable text format.

  - `json`: Emit JSON messages to stdout.

  - `short`: Emit shorter, human-readable text messages.

### Manifest Options

--manifest-path PATH

  Path to the `Cargo.toml` file. By default, Cargo searches in the current directory or any parent directory for the `Cargo.toml` file.

--frozen
--locked

  Either of these flags requires that the `Cargo.lock` file is up-to-date. If the lock file is missing, or it needs to be updated, Cargo will exit with an error. The `--frozen` flag also prevents Cargo from attempting to access the network to determine if it is out-of-date.

  These may be used in environments where you want to assert that the `Cargo.lock` file is up-to-date (such as a CI build) or want to avoid network access.

### Common Options

-h
--help

  Prints help information.

-Z FLAG…​

  Unstable (nightly-only) flags to Cargo. Run `cargo -Z help` for details.

### Miscellaneous Options

-j N
--jobs N

  Number of parallel jobs to run. May also be specified with the `build.jobs` config value. Defaults to the number of CPUs.

## PROFILES

Profiles may be used to configure compiler options such as optimization levels and debug settings. See the reference for more details.

Profile selection depends on the target and crate being built. By default the `dev` or `test` profiles are used. If the `--release` flag is given, then the `release` or `bench` profiles are used.

Target | Default Profile | `--release` Profile
--- | --- | ---
lib, bin, example | `dev` | `release`
test, bench, or any target in "test" or "bench" mode | `test` | `bench`

Dependencies use the `dev`/`release` profiles.

## ENVIRONMENT

See the reference for details on environment variables that Cargo reads.

## Exit Status

0

  Cargo succeeded.

101

  Cargo failed to complete.

## EXAMPLES

1. Apply compiler suggestions to the local package:

       cargo fix

2. Convert a 2015 edition to 2018:

       cargo fix --edition

3. Apply suggested idioms for the current edition:

       cargo fix --edition-idioms

## SEE ALSO

cargo(1), cargo-check(1)