cargo-fix(1)
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 to the next. The general procedure is:
- Run
cargo fix --edition
. Consider also using the--all-features
flag if your project has multiple features. You may also want to runcargo fix --edition
multiple times with different--target
flags if your project has platform-specific code gated bycfg
attributes. - Modify
Cargo.toml
to set the edition field to the new edition. - 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 aftercargo 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 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 thetest
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 thebench
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 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>
. Runrustc --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.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 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 thetest
cfg option. See rustc tests for more detail.See the reference 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 filecargo-timing.html
to thetarget/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 thebuild.target-dir
config value. Defaults totarget
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
- Do not print cargo log messages.
May also be specified with the
term.quiet
config value. --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. Can be specified multiple times
and consists of comma-separated values. Valid values:
human
(default): Display in a human-readable text format. Conflicts withshort
andjson
.short
: Emit shorter, human-readable text messages. Conflicts withhuman
andjson
.json
: Emit JSON messages to stdout. See the reference for more details. Conflicts withhuman
andshort
.json-diagnostic-short
: Ensure therendered
field of JSON messages contains the “short” rendering from rustc. Cannot be used withhuman
orshort
.json-diagnostic-rendered-ansi
: Ensure therendered
field of JSON messages contains embedded ANSI color codes for respecting rustc’s default color scheme. Cannot be used withhuman
orshort
.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 withhuman
orshort
.
Manifest Options
--manifest-path
path- Path to the
Cargo.toml
file. By default, Cargo searches for theCargo.toml
file in the current directory or any parent directory. --ignore-rust-version
- Ignore
rust-version
specification in packages. --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 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. --frozen
- Equivalent to specifying both
--locked
and--offline
. --lockfile-path
PATH- Changes the path of the lockfile from the default (
<workspace_root>/Cargo.lock
) to PATH. PATH must end withCargo.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 and requires the
-Z unstable-options
flag to enable (see #14421).
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 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 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 examplecargo -C path/to/my-project build
.This option is only available on the nightly channel and requires the
-Z unstable-options
flag to enable (see #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. 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 stringdefault
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
andworks
, 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), whereascargo fix -j1 --keep-going
would definitely run both builds, even if the one run first fails.
ENVIRONMENT
See the reference for details on environment variables that Cargo reads.
EXIT STATUS
0
: Cargo succeeded.101
: Cargo failed to complete.
EXAMPLES
-
Apply compiler suggestions to the local package:
cargo fix
-
Update a package to prepare it for the next edition:
cargo fix --edition
-
Apply suggested idioms for the current edition:
cargo fix --edition-idioms