Ubuntu Manpage: cargo-fix — Automatically fix lint warnings reported by rustc

Provided by: cargo_1.75.0+dfsg0ubuntu1~bpo0-0ubuntu0.20.04_amd64

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!

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 apply all fixes
to the current package, you can run:

cargo fix

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

cargo fix is only capable of fixing code that is normally compiled with cargo check. If
code is conditionally enabled with optional features, you will need to enable those
features for that code to be analyzed:

cargo fix --features foo

Similarly, other cfg expressions like platform-specific code will need to pass --target to
fix code for the given target.

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

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>.

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. The general procedure is:

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 of the caveats mentioned above that 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 this may
require manual changes after building with the new edition.

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 next edition. This will not update the
edition in the Cargo.toml manifest, which must be updated 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.

--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 workspaces 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.

--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 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 and supports
common Unix glob patterns.

--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
The feature flags allow you to 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/guide/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.

--ignore-rust-version
Fix the target even if the selected Rust compiler is older than the required Rust
version as configured in the project’s rust-version field.

--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
-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
<https://doc.rust-lang.org/cargo/reference/config.html>.

-q, --quiet
Do not print cargo log messages. May also be specified with the term.quiet config
value <https://doc.rust-lang.org/cargo/reference/config.html>.

--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
<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
--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.

--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.

--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 that 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>.

Common Options
+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.

-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
<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.

EXIT STATUS

       •  0: Cargo succeeded.

       •  101: Cargo failed to complete.

EXAMPLES

        1. Apply compiler suggestions to the local package:

               cargo fix

        2. Update a package to prepare it for the next edition:

               cargo fix --edition

        3. Apply suggested idioms for the current edition:

               cargo fix --edition-idioms