CARGO-CHECK(1)

🎀 cargo-check(1) — General Commands Manual 🎀

NAME

cargo-check — Check the current package 💖

SYNOPSIS

cargo check [options]

DESCRIPTION

Okay bestie, listen up: this checks a local package and all of its dependencies for errors. The way it does that is it basically compiles everything but skips the final code-generation step, which means it's faster than running cargo build. The compiler still saves metadata files to disk, so future runs reuse them if the source hasn't been modified. But heads up: some diagnostics and errors only show up during code generation, so they inherently won't be reported with cargo check. No cap. 🫶

OPTIONS

Package Selection

By default, when you don't pass any package selection options, the packages selected depend on the selected manifest file (based on the current working directory if --manifest-path isn't given). If the manifest is the root of a workspace, then the workspace's 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 that's 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*… — Check 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 — Check all members in the workspace. 👑
• --all — Deprecated alias for --workspace. (It still works, but it's giving old news. Use --workspace instead, bestie.) 💀
• --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 check will check all binary and library targets of the selected packages. Binaries are skipped if they have required-features that are missing.

Passing target selection flags will check 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 — Check the package's library. 📚
• --bin *name*… — Check the specified binary. This flag may be specified multiple times and supports common Unix glob patterns. 🔥
• --bins — Check all binary targets. ✨
• --example *name*… — Check the specified example. This flag may be specified multiple times and supports common Unix glob patterns. 🌸
• --examples — Check all example targets. 💖
• --test *name*… — Check the specified integration test. This flag may be specified multiple times and supports common Unix glob patterns. 🧚
• --tests — Check 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*… — Check the specified benchmark. This flag may be specified multiple times and supports common Unix glob patterns. ⭐
• --benches — Check 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 — Check all targets. This is equivalent to specifying --lib --bins --tests --benches --examples. Periodt. 💅

Feature Selection

The feature flags let you control which features are enabled. When no feature options are given, the default feature is activated for every selected package.

See the features documentation at 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 — Check 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:

• Any supported target in rustc --print target-list. 🔍
• "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). 💅
• A path to a custom target specification. See Custom Target Lookup Path at 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 at 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 documentation at https://doc.rust-lang.org/cargo/reference/build-cache.html for more details. 🫶

• -r, --release — Check optimized artifacts with the release profile. See also the --profile option for choosing a specific profile by name. 🔥
• --profile name — Check 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 at https://doc.rust-lang.org/rustc/tests/index.html for more detail.

See the reference at 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 at 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 at 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 at 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 at 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 at 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. 📄
• --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.

so yeah bestie, that's the other half of the --locked tea. you'd reach for it in environments where you want deterministic builds — like, say, CI pipelines. 🌈

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• --offline — no network, no problem, we ball 🦋

this one straight up stops Cargo from touching the network for literally any reason. without the flag, Cargo will just stop with an error if it needs the network and the network isn't there. with the flag, Cargo will attempt to proceed without the network if possible. ✨

⚠️ beware, bestie: 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, iykyk.

may also be specified with the net.offline config value (https://doc.rust-lang.org/cargo/reference/config.html).

• --frozen — the two-for-one special 🎀 equivalent to specifying both --locked and --offline.

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✨ Common Options ✨

• +toolchain — the rustup bestie entrance 💅

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 — override the config, main character energy 👑

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 — teleport to a different directory 🧚

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.

🙈 heads up: 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. that's it, that's the whole vibe. 💖
• -Z flag — the forbidden nightly stuff 🔥 unstable (nightly-only) flags to Cargo. run cargo -Z help for details.

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🌸 Miscellaneous Options 🌸

• -j N, --jobs N — how many jobs we running in parallel, babe 🏃‍♀️

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 — don't give up after the first L 💪

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 check -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 check -j1 --keep-going would definitely run both builds, even if the one run first fails. 😤

• --future-incompat-report — a lil peek into your future problems, bestie 🔮

displays a future-incompat report for any future-incompatible warnings produced during execution of this command.

see cargo-report(1).

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🌈 ENVIRONMENT 🌈

see the reference (https://doc.rust-lang.org/cargo/reference/environment-variables.html) for details on environment variables that Cargo reads. yes, Cargo is nosy like that. 👀

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💀 EXIT STATUS 💀

• 0: Cargo succeeded. we ate. 🎉
• 101: Cargo failed to complete. it's giving tragedy. 😭

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⭐ EXAMPLES ⭐

1. check the local package for errors:

cargo check

2. check all targets, including unit tests:

cargo check --all-targets --profile=test

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🫶 SEE ALSO 🫶

cargo(1), cargo-build(1)

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and that's a wrap on CARGO-CHECK(1) 💖 go forth and cargo check, bestie — this was your girl CARGO-CHECK(1), signing off, no cap. ✨🎀