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
<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 (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 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 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 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 specified target architecture. Flag may be specified
multiple times. The default is the host architecture. The general
format of the triple is <arch><sub>-<vendor>-<sys>-<abi>.
Possible values:
o Any supported target in rustc --print target-list.
o "host-tuple", which will internally be substituted by the
host’s target. This can be particularly useful if you’re
cross-compiling some crates, and don’t want to specify your
host’s machine as a target (for instance, an xtask in a shared
project that may be worked on by many hosts).
o A path to a custom target specification. See Custom Target Lookup
Path
<https://doc.rust-lang.org/rustc/targets/custom.html#custom-target-lookup-path>
for more information.
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
Output information how long each compilation takes, and track
concurrency information over time.
A file cargo-timing.html will be written to the target/cargo-timings
directory at the end of the build. An additional report with a
timestamp in its filename is also written if you want to look at a
previous run. These reports are suitable for human consumption only,
and do not provide machine-readable timing data.
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:
o auto (default): Automatically detect if color support is
available on the terminal.
o always: Always display colors.
o 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:
o human (default): Display in a human-readable text format.
Conflicts with short and json.
o short: Emit shorter, human-readable text messages. Conflicts with
human and json.
o 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.
o json-diagnostic-short: Ensure the rendered field of JSON messages
contains the “short” rendering from rustc. Cannot be used
with human or short.
o 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.
o 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.
--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:
o The lock file is missing.
o 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
<https://doc.rust-lang.org/cargo/reference/config.html>.
--frozen
Equivalent to specifying both --locked and --offline.
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
o 0: Cargo succeeded.
o 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
SEE ALSO
cargo(1), cargo-check(1)