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:
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 --edition --features foo
Similarly, other cfg expressions like platform-specific
code will need to pass --target to fix code for the given target.
cargo fix --edition --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>
--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.
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.
--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.
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.
The feature flags allow you to control the enabled features for
the "current" package. The "current" package is the
package in the current directory, or the one specified in
--manifest-path. If running in the root of a virtual workspace, then
the default features are selected for all workspace members, or all features
if --all-features is specified.
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. 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 current
directory’s package.
--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 <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.
--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.
--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.
-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
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 <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.
•short: Emit shorter, human-readable text
messages.
•json: Emit JSON messages to stdout. See
the reference
<https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages>
for more details.
•json-diagnostic-short: Ensure the
rendered field of JSON messages contains the "short"
rendering from rustc.
•json-diagnostic-rendered-ansi: Ensure the
rendered field of JSON messages contains embedded ANSI color codes for
respecting rustc’s default color scheme.
•json-render-diagnostics: Instruct Cargo to
not include rustc diagnostics in 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.
--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>.
+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://github.com/rust-lang/rustup/> for
more information about how toolchain overrides work.
-h, --help
Prints help information.
-Z FLAG...
Unstable (nightly-only) flags to Cargo. Run cargo -Z
help for details.
-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 CPUs.