clippy::non_std_lazy_statics: Lints when once_cell::sync::Lazy or lazy_static! are used to define a static variable, and suggests replacing such cases with std::sync::LazyLock instead. Note: This lint will not trigger in crate with no_std context, or with MSRV < 1.80.0

lazy_static! {
    static ref FOO: String = "foo".to_uppercase();
}
static BAR: once_cell::sync::Lazy<String> = once_cell::sync::Lazy::new(|| "BAR".to_lowercase());

static FOO: std::sync::LazyLock<String> = std::sync::LazyLock::new(|| "FOO".to_lowercase());
static BAR: std::sync::LazyLock<String> = std::sync::LazyLock::new(|| "BAR".to_lowercase());

[lints.clippy]
non_std_lazy_statics = "warn"

#![warn(clippy::non_std_lazy_statics)]

cargo clippy -- -W clippy::non-std-lazy-statics

Clippy's own documentation

What it does

Lints when once_cell::sync::Lazy or lazy_static! are used to define a static variable, and suggests replacing such cases with std::sync::LazyLock instead.

Note: This lint will not trigger in crate with no_std context, or with MSRV < 1.80.0. It also will not trigger on once_cell::sync::Lazy usage in crates which use other types from once_cell, such as once_cell::race::OnceBox.

Why restrict this?

• Reduces the need for an extra dependency
• Enforce convention of using standard library types when possible

Example

lazy_static! {
    static ref FOO: String = "foo".to_uppercase();
}
static BAR: once_cell::sync::Lazy<String> = once_cell::sync::Lazy::new(|| "BAR".to_lowercase());

Use instead:

static FOO: std::sync::LazyLock<String> = std::sync::LazyLock::new(|| "FOO".to_lowercase());
static BAR: std::sync::LazyLock<String> = std::sync::LazyLock::new(|| "BAR".to_lowercase());

Configuration

• msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

  (default: current version)

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

Related lints

• too_many_linesChecks for functions with a large amount of lines
• missing_errors_docChecks the doc comments of publicly visible functions that return a Result type and warns if there is no # Errors section
• must_use_candidateChecks for public functions that have no #[must_use] attribute, but return something not already marked must-use, have no mutable arg and mutate no statics
• needless_raw_string_hashesunnecessary hashes around raw string literal
• no_effect_underscore_bindingbinding to `_` prefixed variable with no side-effect
• no_mangle_with_rust_abi`#[no_mangle]` set on a function with the default (`Rust`) ABI
• nonminimal_boolChecks for boolean expressions that can be written more concisely
• option_as_ref_clonedcloning an `Option<_>` using `.as_ref().cloned()`
• option_optionuse of `Option<Option<T>>`

All 847 Clippy lints · Rust compiler errors · Cargo.toml checker